Environmental effects of heavy metal pollution are considered as a widespread problem throughout the world, as it jeopardizes human health and also reduces the sustainability of a cleaner environment. Removal of such noxious pollutants from wastewater is pivotal because it provides a propitious solution for a cleaner environment and water scarcity. Adsorption treatment plays a significant role in water remediation due to its potent treatment and low cost of adsorbents. In the last two decades, researchers have been highly focused on the modification of adsorption treatment by functionalized and surface-modified nanomaterials which has spurred intense research. The characteristics of nano adsorbents attract global scientists as it is also economically viable. This review shines its light on the functionalized nanomaterials application for heavy metals removal from wastewater and also highlights the importance of regeneration of nanomaterials in the view of visualizing the economic aspects along with a cleaner environment. The review also focused on the proper disposal of nanomaterials with crucial issues that persist in the adsorption process and also emphasize future research modification at a large-scale application in industries.

Pressure on alternative fuels and strict environmental regulations are driving a strategic shift in the efficient use of renewable biofuels. One of the promising biofuel candidates recently interested by scholars is a biological or organic additive that is added into diesel or biodiesel fuel to improve engine performance and reduce pollutant emissions. With efforts to improve efficiency and combustion quality in cylinders, combustion characteristics, flame structure and emission formation mechanism in compression ignition (CI) engines using blended fuel with organic additives have been studied on the effect of additive properties on the combustion behaviour. In this review, the physicochemical properties of typical organic additives such as ethers compounds and their effects on engine performance and emission characteristics have been discussed and evaluated based on conclusions of recent relevant literature. The results of the analysis revealed the prospect of using ether additives to improve combustion in cylinders and reduce pollutant emissions from CI engines. Obviously, the presence of higher oxygen content, lower viscosity and density, and higher cetane number resulted in a positive change in the combustion dynamics as well as a chain of mechanisms for the formation of pollutant precursors in the cylinder. Therefore, ether additives have a significant contribution to the sustainable energy strategy of the transportation sector in the next period when internal combustion engines still dominate in the competition for energy system choices equipped on vehicles.

Pressure on alternative fuels and strict environmental regulations are driving a strategic shift in the efficient use of renewable biofuels. One of the promising biofuel candidates recently interested by scholars is a biological or organic additive that is added into diesel or biodiesel fuel to improve engine performance and reduce pollutant emissions. With efforts to improve efficiency and combustion quality in cylinders, combustion characteristics, flame structure and emission formation mechanism in compression ignition (CI) engines using blended fuel with organic additives have been studied on the effect of additive properties on the combustion behaviour. In this review, the physicochemical properties of typical organic additives such as ethers compounds and their effects on engine performance and emission characteristics have been discussed and evaluated based on conclusions of recent relevant literature. The results of the analysis revealed the prospect of using ether additives to improve combustion in cylinders and reduce pollutant emissions from CI engines. Obviously, the presence of higher oxygen content, lower viscosity and density, and higher cetane number resulted in a positive change in the combustion dynamics as well as a chain of mechanisms for the formation of pollutant precursors in the cylinder. Therefore, ether additives have a significant contribution to the sustainable energy strategy of the transportation sector in the next period when internal combustion engines still dominate in the competition for energy system choices equipped on vehicles.

Marine diesel engines are one of the main sources of air pollution. Exhaust gases of diesel engines have many different harmful components, especially nitrogen oxides with the general formula NOx. Currently, there are many methods and research directions to limit NOx emissions in diesel engine exhaust, each method has its own strengths and limitations. In order to obtain the efficient energy development with less polluted environment with existing marine diesel engines, continuous efforts have gone into research and development of wet technologies, which have the potential to reduce nitric oxides (NOx) and particulate matter (PM) emissions simultaneously with improved performance level. The main objective of this review is to shed light on the role of typical water addition technologies such as water-in-fuel emulsion, intake air humidification – humid air motor and direct water injection in reducing NOx and PM emissions in marine engines. We have made a comparison of the effectiveness of different methods used to reduce the emission of nitrogen oxides. Advantages and disadvantages of supplying water into the combustion chambers of diesel engines have been shown together with the comparison of the range of changes in their construction.

Diesel engines remain the most widely used option to power a wide variety of transport ships. In terms of the maximum installed volume of all shipping vessels, 96% of this energy is generated from diesel engines. Due to the lack of alternative propulsion systems with the same energy density, cost, and fuel efficiency as diesel engines, it is not expected that marine diesel engines will be replaced within an expected 100 years. Modern large diesel engines are about 50% efficient in using the burning thermal energy of the fuel and the rest is lost to the environment as waste heat. The efficient use of waste heat energy can enhance the power system efficiency and reduce emissions, by using a dedicated waste heat recovery system for power generation or heating needs. Technologies that recover waste heat from engines have been around for 30 years, but recovery efficiency, cost of installation, and the ability to take up space in engine room space have caused certain obstacles. This paper conducts a brief review of the techniques and prospects of emerging waste heat recovery technologies from marine diesel engines. The results achieved would be useful suggestions for ship managers and owners in equipping marine fleets with waste heat recovery systems to meet the increasingly stringent IMO requirements for energy efficiency and environmental protection.

: The type of technology used to strengthen the surface structure of machine parts, typically by carbon-permeation, has made a great contribution to the mechanical engineering industry because of its outstanding advantages in corrosion resistance and enhanced mechanical and physical properties. Furthermore, carbon permeation is considered as an optimal method of heat treatment through the diffusion of carbon atoms into the surface of alloy steel. This study presented research results on the thermodynamic calculation and simulation of the carbon permeability process. Applying Fick’s law, the paper calculated the distribution of carbon concentration in the alloy steel after it is absorbed from the surface into the internal of the sample. Using the SYSWELD software, an analysis was performed on the carbon permeability process to determine the distribution of carbon concentrations in 20CrMo steel that was then followed by a detailed analysis of the microstructure of the sample post the carburizing process. According to the calculation results, the surface carbon content was 0.9% and steadily decreased into the core. After 3 hours, the depth of the absorbent layer was measured at 0.5 mm for both the cylindrical and cubic samples. By analyzing the phase, the distribution of martensite phases such as ferrite/pearlite and residual austenite was also determined after the carburizing process.

========================================================== Available online: 31 October 2020 This article has been retracted by International Journal on Advanced Science, Engineering and Information Technology Editorial team, following clear correspondence and confirmation with authors. The paper is retracted from 18 July 2022. ========================================================== Currently, traditional fossil energy is gradually exhausted for sustainable economic development, and environmental protection is an urgent requirement for all countries. Therefore, the issue of saving energy, as well as exploiting renewable energy sources, is being prioritized for development. The braking system collects dynamic energy, also known as the regenerative braking system, which is understood as the brake system; instead of converting kinetic energy into heat, the brake system can collect and store energy. The brake system of the bus in use is usually frictional. During braking, this type of brake system converts the vehicle's kinetic energy into heat, dissipates it into the surrounding environment, and cannot be recovered. Moreover, due to the operational characteristics, the bus has high stopping frequency and high braking capacity, leading to wasted energy, in addition to producing many emissions causing environmental pollution. This study focuses on experimental research for evaluating the dynamic energy acquisition of the mechanical brake system on a school bus as a function of operating parameters such as vehicle speed according to gears, vehicle mass as well as hydraulic pressure parameters. The results are noticed that the highest dynamic energy recovery rate is about 35% in the lowest gear. In the case, from the initial braking velocity of 30km/h to 0 km/h, the initial working pressure of the hydraulic tank is 100bar, the dynamic energy recovery rate is about 25%.

Recently, due to global warming and urbanization, there are many major cities that may face the challenge of day zero next decades. Obviously, water is an indispensable component for maintaining life on the earth. Although portable water is required of the hour, the quantity of available freshwater is impacted significantly by sea-level rise and pollution from industrialization. As a consequence of the global water crisis, different methods for clean water production from brackish water have been studied and developed in practice, however, the solar distillation of water is the most economical and desirable approach due to this method utilize solar energy that is the environmentally friendly and economical resource. Over the last 15 years, the impressive price drop of the photovoltaic solar collector (PV/T) makes them popular and easy to access. As a result, the employment of PV/T in solar stills is emerging as a potential device for water distillation. Therefore, in this paper, an active solar distiller combined with a photovoltaic panel has been reviewed for improvement of the distillate yield and effectiveness of solar photovoltaic. This review work presents a variety of studies on various types of solar still (for example conventional solar still (CSS), double slope solar still (DSSS), stepped solar distiller, and cascade solar still) couples with different solar water collectors (such as flat plate collector (FPC) and evacuated tubes collector (ETC)) and solar photovoltaic modules. It is obtained that the hybrid PV/T active solar still improves the distillate yield, energy efficiency, and exergy efficiency as compared to passive mode. The cooling method enhances the performance of the photovoltaic solar collector as well as the productivity of solar still. Moreover, the environmental economic estimation reveals that the solar still coupled with the PV/T mitigated considerably the amount of CO2. It can be stated that it is suitable to commercialize the hybrid PV/T active solar still for supplying not only electricity but drinking water also. Finally, this review paper also suggests the scope for the research in the future.

This paper presents a study of compression ratio in a CNG fuel cylinder engine to form an external mixture, the research results show that changing the compression ratio has improved thermal efficiency not only in manufacturing, large load but also in local download mode. The main reason for improving the thermal efficiency at the local load is to reduce the amount of heat generated by the exhaust gas without changing the heat transfer to the cooling water. But the source of this problem is due to the expansion and more thorough production of the combustion gas in the engine cylinder than the engine with a fixed compression ratio. The limited compression ratio found from this study is epsilon(gh) = 15 when the octane requirement is approximately ON = 130, this limited compression ratio value will be the first basis to design the replacement system. convert compression ratio.

==========================================================Available online: 31 December 2020This article has been retracted by International Journal on Advanced Science, Engineering and Information Technology Editorial team, following clear correspondence and confirmation with authors.The paper is retracted from 29 November 2021.==========================================================With the advantage of reducing the damage of bending stress up to 10%, the straight-toothed bevel gears (STBG) with a shoulder-bearing are being used in many industries automobiles, trains, mining, space, machinery technology and aviation equipment. With the working characteristics of straight-tooth bevel gear, the manufacturing quality assessments are usually conducted through micro-dimensional values, surface gloss, and internal surfaces' contact ability in the transmission. Recently, research and application of gear machining methods on 3-axis CNC milling machines are gradually becoming more popular. Therefore, the study of the affection of technology parameters on the quality of shaping the STBG surface by evaluating the output factors (surface undulation, micro-geometry parameters and trace contact size) in the finishing step is very urgent. First of all, the paper goes into detail in building design solutions to create input data for the machining of STBG on CNC milling machines by profile attachment method. Moreover, the study also built the process of evaluating the machining quality of the STBG utilizing microgeometry and the contact size. The paper focuses on developing experimental equations that show the relationship between technological parameters (S, F, Z) and roughness (Ra), deviation of tooth profile shape (ff), and trace contact size (bc, hc) of the Z11-16 m8 STBG transmission. From that, the optimal technology solution was identified to ensure the contact accuracy when processing the Z16-11 m8 STBG transmission on a 3-axis CNC milling machine.

— Biofuels are mainly composed of bioethanol and biodiesel, biogas. In particular, biodiesel can completely replace diesel fuel based on similar properties of cetane value, specific calorific value ... and its environmental friendliness. Biodiesel is a liquid biofuel with similar properties and can be used as a substitute for conventional diesel oil. Tests using biodiesel (BDF) on internal combustion engines have also been conducted. The results of these tests show that BDF can be used on engines at any rate mixed with diesel fuel without changing engine structure. In addition, using BDF reduces harmful emissions into the environment such as CO, SO2, PM, CxHy .... [9, 10]. Emission factors of engine pollutants, combustion efficiency of fuel and engine power depend on BDF mixing ratio in fuel and engine load. Study to assess engine fuel consumption and ordinary emissions of palm oil biodiesel fuel (BDF palm oil) used on diesel generators. The experiments were performed at no-load and high-load mode with mixing ratios of BDF palm oil and diesel fuel (0%, 5%, 10%, 15%, 20%, 50%, 100% are equivalent to B0, B5, B10, B15, B20, B50, B100). Results showed that specific fuel consumption increased as volume of BDF palm oil increased in fuel. In idle mode, compared to diesel fuel, fuel consumption increased by 1.32%; 1.8%; 2.8%; 3.74%, 5.61%; 6.54% corresponding to B5, B10, B15, B20, B50, B100. In high load mode, fuel consumption increased by 1.51%; 1.86%; 2.18%; 4.78%; 5.36%; 6.76% corresponding to B5, B10, B15, B20, B50, B100 compared to diesel fuel.

— The development of Vietnamese shipping fleet is quite fragmented, the fleet capacity is low, and the management capacity is poor, so many shipping companies operate inefficiently ... limiting the ability to connect shipping. Moreover, the slow movement of goods between Vietnamese seaports has led to the situation that port enterprises have to rotate the positions of containers in yards or between different ports and ICDs. This increases the cost and reduces the efficiency of port operation, greatly affecting the import and export activities throughout the country. One of the major difficulties of the port area is that the infrastructure connected to the cargo concentration area is still weak. In particular, localities still lack of specialized delivery and service centers. Inadequacies in exploiting and managing the seaport system in Vietnam make import-export enterprises spend a lot of time and costs in exporting goods, reducing the competitiveness of Vietnamese goods. The paper presents inadequacies and weaknesses of the seaport system in Vietnam; on that basis, propose some radical solutions to improve the quality of services at seaports in Vietnam.

In Vietnam, status is mentioned a lot in recent economic and management documents. The scientific basis of the position resources for socio-economic development is still a new issue in our country, and it is not accessible in the world. However, this is a significant direction that the right awareness will create a new perspective on the rational use of resources, spatial organization, and planning of rational and sustainable socio-economic development. Vietnam is particularly crucial in Southeast Asia thanks to a territory stretching over three thousand kilometers on the western edge of the South China Sea and a territorial sea area of over one million square kilometers, three times the area of the territory. The Vietnam Sea is located in a tropical monsoon region, with world-class rivers that the basin covers six countries. The Vietnam Sea plays an essential role in the environment, the ecology of the East Sea and the region, an exclusive transitional zone between the Indian Ocean and the Pacific Ocean in terms of biological and maritime geography. The development of an industrialized and modernized economy must inevitably be linked to the maritime potential of the ocean. This article presents the initial findings on the coastal and coastal status of Vietnam.

— Before the situation of traditional energy reserves on ports decreased, people now focus on researching, exploiting and applying new energy sources. These energy sources are considered clean, renewable energy and they do not pollute the environment. The paper studies the power and exhaust of RT125 diesel engine when using biodiesel. This fuel is made from rubber seed oil with variable mixing ratios B0, B5, B10 and B20, with loading modes of 50%, 80% and 100%. The study was carried out in revolutions of 1600 rpm, 2000 rpm and 2400 rpm. Simulation results by KIVA-3V software show that when changing from diesel (B0) to biodiesel (B5, B10, B20) engine power does not change much, but soot emissions decreased significantly while NOx increased.

— Along with the development of Vietnam's economy, transportation plays an extremely important role in the development process. However, in parallel with this development, transportation development also causes many obstacles in protecting the environment. Although the organization of transport and management of transport means has made great progress, it has not yet met the requirements of reducing congestion in big cities, which are increasingly serious, affecting economic growth and increasing. environmental pollution, reducing the quality of life of people. In line with the current trend of environmental protection, the fact that countries around the world start developing green transportation systems is an indispensable part, Vietnam is not outside this.

In the technical work on low temperature so far lacks a full analysis of the basis of thermodynamic processes using modern methods. Meanwhile, the low temperature conventions widely used in different fields. The purpose of this section is to give readers tools for thermodynamic studies and presents changes in the system on a fairly low temperature, intuitive nature and practices for analysis low-temperature processes related to cold and depth on the basis of using a unified approach. The low temperature process is applied in a number of techniques including basic process repeated. So it is best to preliminary studies the changing characteristics of our energy to then study the overall process.

The fourth industrial revolution, also known as the digital revolution, has taken place since the beginning of the 21st century. The characteristic of this industrial revolution is the increasing popularity of artificial intelligence and automated machines. chemistry, bringing a combination of virtual systems and reality. This revolution has a strong impact on many fields and many aspects of social life, in which a special human resource of high quality is indispensable; but human resources are the direct object of education – training. Education and training play an important role as a key factor and a driving force for the development of the economy. Not only in Vietnam but also in most other countries in the world, governments consider education as a top national policy. So why is education and training so important to the country's development strategy? The quality of Vietnamese education is really alarming in all aspects. If we don't recognize the true nature of the problem, if we just want to have great achievements, want our students to be rewarded and forget about the problem, the future of education will have a lot of defective products. The future of education is the future of the country, the future of every family. Therefore, each person in different positions but with the sincerity of education to join hands will hope for the change. The content of this article will revolve around the inadequacies of Vietnamese education about the status quo, about the reasons why Vietnamese education has not kept up with international friends, thereby proposing solutions for difficulties. the current challenges of the Vietnamese education industry, and the need for innovative reforms to fulfill the mission of the education sector. Good coordination between the three environments including family, school and society will be the key to solving the problem of improving the quality of education in Vietnam. That is the objective of this paper, as the solution improves the connection and interaction efficiency of the three environments mentioned above.

The South China Sea, including the Vietnam Sea, is witnessing significant changes under the impact of both nature and man. These are the impacts of climate change and ocean change with "extreme" signs such as increasing storms, coastal floods, sea level rise, sea acidification, pollution and environmental incidents, ... occur thicker, more intense and irregular. Especially serious degradation of the environment and biodiversity of the sea, increasing environmental incidents, including oil spills, ... due to human impact. Especially the large-scale destruction of coral reefs, seagrass beds in island clusters off the South China Sea has been happening at a worrying rate. The destructive fishing activities of humans in the South China Sea have caused ecosystem degradation and the extinction of some species, such as sea turtles, some sharks and another species. Other fish, especially the giant mussel, the consequence is a decrease in the natural capital of the sea, leading too prolonged "ecological disturbances". The reserves of seafood in the Spratly region (of Vietnam) and the West Sea in the East Sea have decreased by about 19% compared to before 2017. Therefore, the improvement of marine environment quality, including biodiversity conservation and major marine ecosystems are to preserve marine natural assets, contributing to the implementation of Vietnam's green growth strategy and action plan. This is the path that Vietnam has chosen to both grow marine economy, adapt to climate change, and protect the environment both in the short and long term, towards sustainable development.

It should be determined that the marine engine operation at a low load operation (especially 40% or less) is not conducive to the operation of the engine and related equipment. However, manufacturers accept and allow the engine to operate continuously at such a low load condition. The mode operates at a low load of marine engines that drive the propeller is used quite recently in various reasons. The S46 ME-B8.5 engine concept consists of a hydraulicmechanical system for activation of the fuel injection. The fuel pressure booster consists of a simple plunger powered by a hydraulic piston activated by oil pressure. An electronically controlled proportional valve controls the oil pressure. The exhaust valve is activated by a light camshaft, driven by a chain drive placed in the aft end of the engine. However, at low load operation, the MAN B&W S46ME-B8.5 engines have generated several incidents that greatly affect the operation of the ship including a malfunction on the exhaust valve and troubles of jamming plungers of the high-pressure pump during engine acceleration and start-up. Therefore, it is essential to learn and identify structural and operational characteristics of the S46 ME-B8.5 engines. Moreover, it is necessary to analyze the effects on the process of low-load operation as sailing. The paper focuses on studying the operating characteristics of engines in low load mode, assessing the effects of this mode on engines and related machines. Besides, this study also developed the operation process for S46ME-B8.5 engines. In this paper, the authors propose solutions to effectively operate the S46 ME-B8.5 engines in low load mode when traveling on the sea.

Nowadays, the use of exhaust gas energy seems to be a very promising key to increase the energy efficiency in maritime field by converting the thermal losses of ship into useful energy sources such as exhaust boiler, exhaust turbo charging or mini electrical generator, which ensure the best utilization of the fuel, reduce emission met IMO requirements and reduce the operating costs. Diesel engine exhaust gas energy, certainly the most interesting among the waste heat sources of a ship because of the heat flow and temperature, is always considered to utilize due to the exhaust gas energy is approximately 25-30% of total energy of burned fuels in internal combustion engines. By installing the main propulsion plant with a waste heat recovery system (WHRS), the fuel can be utilized more economically, because energy lost in the exhaust gas flow is less. Moreover, the amount of CO2 emissions related to the mechanical power output of engines may be dropped off. The paper presents the review of utilization of exhaust gas heat in ship and suggests a heating up method for biodiesel or bio-oils which fuel in diesel engine in order to get dual benefit.