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Given a family of null hypotheses H 1 , ... , H s , we are interested in the hypothesis H s γ that at most γ − 1 of these null hypotheses are false. Assuming that the corresponding p-values are independent, we are investigating combined p-values that are valid for testing H s γ . In various settings in which H s γ is false, we determine which combined p-value works well in which setting. Via simulations, we find that the Stouffer method works well if the null p-values are uniformly distributed and the signal strength is low, and the Fisher method works better if the null p-values are conservative, i.e. stochastically larger than the uniform distribution. The minimum method works well if the evidence for the rejection of H s γ is focused on only a few non-null p-values, especially if the null p-values are conservative. Methods that incorporate the combination of e-values work well if the null hypotheses H 1 , ... , H s are simple. Finally, we also consider nonparametric permutation-based combination methods. They are useful for addressing the conservativity of parametric p-values which are computed under least favourable parameter configurations. [ABSTRACT FROM AUTHOR]

Among the effective solutions for the reduction of environmental pollution, the use of fuels with limited-sulphur content or bio-based fuel has been paid much attention due to their advantages. In this experimental work, the ultra-low-sulphur fuel (ULSD) was mixed with biodiesel extracted from Jatropha oil (JOB) after being processed with ultrasonic assistance. There were eight samples used for mixture preparation of ULSD and JOB based on the correlation of viscosity aiming to find the optimal mixing rate for ULSD and JOB. As a result, the stability of the ULSD–JOB emulsion reached 98.5% after 17 min of the ultrasonic treatment with a mixing rate of 50%(ULSD): 50%(JOB) in the case of a distance of ultrasound horn tip to the bottom of vessel of 90 mm. In addition, the similarity of spray characteristics, being penetration length and cone angle, for the ULSD–JOB emulsion compared to a type of diesel oil was reported. The ULSD–JOB emulsion produced by ultrasound delivered a fuel with the ultra-low-sulphur content and increased oxygen content. The above-mentioned emulsion has well satisfied the increasingly stricter requirements of IMO regulations, as well as meeting the recommendations of engine manufactures regarding the fuels used in marine diesel engines. [ABSTRACT FROM AUTHOR]

In recent years, 2,5-dimethylfuran (DMF) has been seen as a potential chemical substance in replacing the traditional petroleum because their physicochemical properties have many similarities with gasoline and diesel, and they have some outstanding advantages compare to other biofuels. Due to those properties, there have been many studies conducted on the combustion behavior and emission characteristics of engines fueled with DMF and its blends. However, DMF was found to have a great tendency to generate soot precursors from the combustion process due to its ring structure, showing that further investigations of the formation tendency for particulate matter (PM) and soot when using DMF as an alternative fuel on internal combustion engines are extremely necessary. Therefore, in the current work, the formation mechanism of PM and soot from the DMF-based fuel combustion was thoroughly analyzed. More importantly, the relationship between the oxidation/pyrolysis reactions and the routes of PM formation and soot tendency in spark and compression ignition engines were discussed in detail. Based on obtained results, DMF was concluded to be a promising alternative fuel after blending with gasoline or diesel fuel rather than using pure mode. However, the other comprehensive assessments on engine performance characteristics, the impacts of DMF on the engine and fuel system durability, and the economic and environmental criteria should be carried out in the future. [ABSTRACT FROM AUTHOR]

The rapid depletion of fossil fuels and the strengthening of emission regulations have been considered as the primary issues in the global energy and environment field, suggesting that the increase in the percentage of alternative fuels in the transport sector is believed to be a prospective pathway. Among the renewable biofuels that have attracted great interest, 2,5-dimethylfuran (DMF) is found to offer several attractive combustion features, of which the ignition behavior is known as a global parameter. Therefore, several experimental studies and prediction models have been used to determine the ignition behavior of DMF. However, the ignition behavior of DMF in comparison with other fuels, which is important for further model development and engine applications, has not been completely understood as well as the relationship between the reaction mechanism of DMF and its ignition behavior. Moreover, the predictions of existing models of DMF still need improvement with respect to chemical kinetic modeling. In this review paper, ignition behavior for DMF was thoroughly analyzed in cases of changing the initial parameters. More importantly, ignition delay times of DMF were determined and compared with other promising fuels, suggesting that DMF could become potential fuel for spark-ignition engines. However, the studies on the use of DMF for the engine should be completely conducted and thoroughly detailed to have a comprehensive look into the applicability of DMF as a green and alternative fuel in the future. [ABSTRACT FROM AUTHOR]

Biodiesel has been considering as promising fuel in the situation of ever-depleting fossil fuels and serious environment pollution. Beside clearly known advantages, high viscosity and density, and high surface tension are the acute disadvantages that need to be improved to use directly for an unmodified diesel engine. In this work, 24 samples of biodiesel–diesel fuel blends created by mixing respectively 5%, 10%, 20%, 40%, 50%, 60%, 75% and 100% of fractions of Coconut oil biodiesel (COB), Jatropha oil biodiesel (JOB), Waste oil biodiesel (WOB) in diesel fuel were used for experimental purposes. In the first stage, the effects of biodiesel fractions and temperature on kinematic viscosity and density were developed. In the second stage, the effects of kinematic viscosity and density on fuel supply system, fuel pump network, fuel filters, and spray characteristics (including penetration length (Lb) and Sauter Mean Diameter (SMD)) were investigated. Obtained results of this study based on experimental correlation and mathematical equation showed over 95% of the confident level from a regression correlation equation regarding kinematic viscosity and density. [ABSTRACT FROM AUTHOR]

The extremely serious effects of the marine environment pollution due to oil spill, oil slick and toxic heavy metals on the human, ecosystem, and society are clearly seen. Findings of absorbent materials with high absorption capacity and high usage efficiency are being much interested by several researchers. In this work, four samples of absorbent material fabricated after adding, respectively, 5%, 25% of rice straw mass percentage along with 0.5 and 3 mm of rice straw size, four oil types including crude oil, fuel oil (FO), diesel oil (DO), kerosene, and a solution containing toxic heavy metals such as Cd2+, Pb2+, Hg2+ are used for the experimental purposes related to the evaluation of the oil absorption capacity (OAC) and toxic heavy metal, and the oil removal efficiency (ORE) during 120–150 min. As a result, the as-used sample with 25% of rice straw mass and 0.5 mm of rice straw size shows the highest absorption capacity. In addition, the influence of capillary pressure on the OAC and ORE is analysed, the assistance of Scanning Electron Microscope (SEM) for observation of porous structure of rice straw, pristine PU, and the as-fabricated absorbent are also conducted and presented in this study. [ABSTRACT FROM AUTHOR]

The solar still utilizes solar energy to produce potable water from brackish water, which may support agricultural and industrial sectors as well as the life of humans and animals. A conventional solar still normally distills an average freshwater of 2 L/m2/day which is not sufficient to meet individual daily demand. As a motivation for productivity enhancement, a new model of solar water distiller has been experimented with under Thailand climatic conditions. Its structure is not like a typical solar still, the low-temperature brackish water was supplied from the water tank to the condenser tubes for condensation rate improvement. After making a turn, the brackish water was heated up in blackened receiver tubes by absorbing solar radiation, which leads to a temperature growth of the feed water. The high temperature of outlet water in the receiver tubes plays a role as an additional heat for brackish water in the basin, which will enhance the temperature of basin water along with the evaporation rate. Various water feed rates and a variety of water depths were studied for their effect on the performance of the proposed solar still. The experimental conditions consisted of 0.5 cm, 1 cm, and 2 cm of water levels and 0.5 L/h and 1 L/h of mass flow rates. As the water level decreased from 2 cm to 0.5 cm, the daily productivity was improved by 34%. Additionally, there is a 28% growth in output as the mass flow rate of feed water declined from 1 L/h to 0.5 L/h. Further remarkably, in comparison with a conventional solar still under the same level of water depth, the daily distillate yield of the proposed model improved double and 58.5% at a water depth of 0.5 cm and 1 cm, respectively. [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, lockdowns at city-to-nation levels were enforced in many places in the world aiming to restrict the spread rate of COVID-19. Due to the forced restrictions, many human activities were considerably slowed down just within a few days, leading to drastic reductions in NO2 levels across the world. As reported, the nations and regions contributing to the huge NO2 emissions in the world such as China, United States, and Europe have seen a remarkable decline in NO2 during the lockdown period as compared to the same time of 2019, resulting in the estimation of reducing 20% of NO2 emissions in 2020 globally. This review paper has provided detailed information relating to the NO2 concentrations across most regions and countries in the world. Moreover, the effects of the behavior of countries during the lockdown as well as the main sources emitting NO2 emissions were also thoroughly analyzed. In general, this study is believed to supply useful information to the regulatory bodies for the strategies of the pollution source control. More importantly, controlling such temporary NO2 pollution source in a reasonable interval may be considered as a useful and effective measure to heal the environment and to reduce the pain of “the earth mother”. [ABSTRACT FROM AUTHOR]

Several researchers and manufacturers are paying attention to technologies of waste heat recovery due to its effectiveness in the conversion of the energy from exhaust gas into electric power. Therefore, the analysis of the effects of thermoelectric generator (TEG) design on the power generation characteristics is an essential issue to develop its applications to waste heat recovery technologies aiming at pollution environment reduction and improvement of efficiency for energy use. In this study, a TEG based on the thermoelectric module (TEM) with fishbone-shaped fins was built for experimental purposes. The comparison of power generation characteristics including voltage and power output, conversion efficiency, and pressure drop for the fabricated TEM-based TEG with fishbone-shaped fins and TEM-based TEG without fins under conditions of the hot inlet gas temperatures from 200-500°C along with the changes in mass flow rate of hot inlet gas was conducted. The results indicated that TEM with fishbone-shaped fins had a maximum increase by 30.7 V of voltage output, 17.54 W of power output, 3.68% of conversion efficiency compared to the case of TEM without fishbone-shaped fins. However, the average pressure drop for TEM with fishbone-shaped fins was 3.65 Pa higher than that of TEM without fishbone-shaped fins. The experimental study showed that TEM-based TEG system had achieved high conversion efficiency by attaching the fishbone-shaped fins to the surface of the hot side in the TEG structure. [ABSTRACT FROM AUTHOR]

Operation control combined with the optimization of the structure for thermoelectric generators (TEGs) based on thermoelectric modules (TEMs) is an effective method to improve the power generation characteristics of TEGs. The present study is intended to experimentally investigate the power generation characteristics including voltage and power output, and conversion efficiency of a TEM-based TEG, which is added fishbone-fins aiming to enhance heat exchange of hot inlet air to the hot side of TEG. The effects of mass flow rate (MFR) of cooling water on the power generation characteristics of TEGs are analyzed in the case of the hot inlet air temperatures of 200–500°C and a constant MFR of hot inlet air. Compared to TEM-based TEG without fishbone-shaped fins, TEM-based TEG with fishbone-shaped fins has a maximum increase by 31.37 V of voltage output and 16.49 W of power output. Conversion efficiency of TEM-based TEG with fishbone-shaped fins is determined through the temperatures of hot side and cold side as well as figure-of-merit (ZT). As a result, an average increase of 2.93% of the conversion efficiency for TEM-based TEG with fishbone-shaped fins compared to the case of TEM without fishbone-shaped fins is found. In addition, the outlet temperature of cooling water is also practically measured to evaluate the influences of fishbone-shaped fins on the heat flux transferred from hot side to cold side of TEM. [ABSTRACT FROM AUTHOR]

The year 2020 has witnessed the extraordinary impact of the coronavirus (COVID-19) outbreak. Across the globe, countries and cities took drastic measures in the attempt to halt the spread of the virus that led to the sudden cease of major economic and transportation activities. As a result, the temporary lockdown periods prompted sharp declines in daily global CO2 emissions. Moreover, the positive impacts on the local environment were evident from reduced production and movements among cities and regions around the world. While there is a much greater sense of urgency in addressing the fallout of the COVID-19 pandemic, the efforts in curbing global carbon emissions and mitigating the potential irreversible consequences of climate change are as equally important in these times of uncertainty. Taking advantage of the COVID-19 recovery schemes to concurrently boost the climate agenda is regarded as a strategic opportunity to ensure a sustainable path for a post-pandemic world. As governments still grapple with the fallout of the pandemic, implications on future climate change policy remain a subject of further investigation. This review aims to examine the effects of COVID-19-related lockdowns on global CO2 emissions while highlighting the need for synchronized solutions to tackle the double threat caused by the current COVID-19 pandemic and climate change crisis. [ABSTRACT FROM AUTHOR]

Biodiesel is the most promising bio-based alternative to the large quantity of fossil diesel fuel used in the transportation sectors. However, its corrosive behavior when in contact with the diesel engine and fuel system components is of serious concern. The present work comprehensively reviews the impacts of biodiesel on the corrosion behavior of metal-based parts in diesel engines such as copper and copper-based alloys, aluminum and aluminum-based alloys, cast iron, carbon steel, and stainless steel. The corrosion mechanisms of the mentioned metals in biodiesel are also presented and discussed in detail. Methods applied to study the corrosion phenomenon and its level are also presented. The reasons leading to the higher corrosiveness of biodiesel vs. diesel fuel, including its higher hygroscopicity, higher electrical conductivity, higher polarity, higher solvency, the presence of water and oxygen in biodiesel promoting microbial growth, and finally, its auto-oxidation resulting in the generation of corrosive agents, i.e., monocarboxylic acids, are also detailed. Finally, the use of corrosion inhibitors in biodiesel to enhance metals/alloys resistance to corrosion is reviewed. Future research needs to further expand biodiesel utilization worldwide are also envisioned. [ABSTRACT FROM AUTHOR]

For centuries, internal combustion engines have played a major role in human society, and an important driving force in the development of transportation. However, along with the socio-economic development, the rapid increase in the number of means of transport and the increasing demand for energy has made human society face great challenges, including the depletion of fossil fuel resources, the threat to energy security, climate change, the rapid increase in environmental pollution and CO2 emission. In this situation, the use of the electric vehicle has been put into consideration and developed in many advanced countries around the world. However, a question is raised whether the demand, infrastructure and policies to support the use of electric vehicles in developing countries, such as Vietnam, are attractive to investors and users and which roadmap for electric vehicles is suitable for Vietnam. In this paper, the prospects for the development of the electric vehicle market in Vietnam have been carefully analyzed for a long-term strategic vision. The roadmap for the use of electric vehicles in Vietnam is illustrated to encourage people to use electric vehicles, to recommend the government to issue reasonable policies, and to attract investors in the field of electric vehicles. In short, the expansion and development of electric vehicles in Vietnam need a long term and specific plan, part of which should be the cooperation of both the community and government in reducing the environmental pollution. [ABSTRACT FROM AUTHOR]

Agricultural and agro-industrial residues are ordinary wastes in the forestry industry and their valorization is an important issue.Cocoa (Theobroma cacao) pods waste was chosen as an activated activated carbon material and studied as active materials for supercapacitor electrodes. The carbon electrode has been made using 0.3 M and 0.4 M Potassium Hydroxide (KOH) activators at 700°C. Physical properties were tested by measuring density, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM), while the electrochemical properties were tested using the Cyclic Voltammetry (CV) method. Activated carbon electrodes were constructed by a combination of chemical activation, and physical activation methods. The technique of making carbon electrodes was started from pre-carbonization, milling, chemical activation, pellet making, carbonization, and physical activation. Analysis of dimensions, density, and specific capacitance in the manufacture of carbon electrodes showed the mass, diameter, thickness, and density of the electrodes decreased with the addition of KOH concentrations from 0.3 M to 0.4 M. While the specific capacitance value of the electrode was directly proportional to the increase of KOH concentration. In XRD measurement data, the values of 2θ in the range of 23.569°–24.747° was obtained for the reflection field 002, and 44.634°–44.781° for the reflection plane 100. X-ray diffraction curve data showed a 0.4 M at 700°C sample having an Lc value and a lattice distance smaller than the sample of 0.3 M at 700°C. Therefore, it could be indicated that the surface area of the sample of 0.4 M at 700°C was greater than the sample of 0.3 M at 700°C. The electrochemical test showed that the method of chemical activation variation of 0.4 M produced electrodes with better performance than 0.3 M. The specific capacitance value obtained at a concentration of 0.3 M was 90.2 F/gr with a density of 0.850 gr/cm3, while at a concentration of 0.4 M was 140.2 F/gr with a density of 0.802 gr/cm3. These results indicate the high potential of agricultural cocoa pods based activated carbon monoliths as supercapacitor electrode. [ABSTRACT FROM AUTHOR]

Stricter regulations on emissions from diesel engines have shifted the conventional combustion to more advanced combustion, aiming to minimize the emissions of NOx and PM. It is believed that it is possible to simultaneously reduce emissions of NOx and PM in diesel engines by applying combustion modes based on either partially premixed compression ignition strategy (PPCI) or premixed charge compression ignition strategy (PCCI). Normally, PCCI/PPCI combustion modes are able to be achieved by employing early injection timing to increase the time available for mixing fuel and air in order to control the combustion phase. Unfortunately, overearly injection timing can lead to the fuel spray missing the piston bowl causing a significant increase in emissions of PM, HC, and CO. The solution given out for early direct injection (EDI) strategy in PCCI combustion condition to overcome high emissions of PM, HC, and CO is the use of narrow-angle direct injection (NADI) to target the fuel spray toward the piston bowl aiming to reduce the wall wetting and fuel spray impingement. Therefore, the main goal of this review work is to evaluate the effects of NADI on the performance, combustion and emission characteristics of diesel engines operated under advanced injection timing-based PCCI combustion mode in comparison to those of conventional combustion. [ABSTRACT FROM AUTHOR]

The development and modernization of the industry are known to bring many benefits for the human life, to diversify the production process and to create the abundant products originated from different materials. Among the above-mentioned products, all kinds of plastic-based commodities have a huge increase in both the quality and quantity due to their large range of applications as well as their versatility in the manufacturing process and the use along with lower cost than other. That is why the Municipal Solid Waste (MSW) from the countries in the world is reported to contain around 12% of plastic. Vietnam is listed as a country among top five importing PW countries from 01/2018 to 11/2018 with about 7.6% total import. Current status shows that Vietnam is a country affected seriously by plastic waste, causing the heavy consequence to environment. In this work, the figures of alarming reality in the use and discharging the plastic waste in Vietnam are exhibited. More importantly, the policy and the scenario for the treatment of the plastic waste in the near future are thoroughly analyzed to find the reasonable solution for reducing the pollution due to plastic waste in Vietnam. In closing, some suggestions for reuse of plastic waste are also given out to recover and treat plastic waste in Vietnamese situation. [ABSTRACT FROM AUTHOR]

In conventional diesel engines (DEs), the auto-ignition and decomposition reactions are considerably dependent on the disintegration of fuel spray and the fuel-air mixing quality. While mixed, localized fuel-rich areas in the combustion chamber also strongly affected the results of the combustion period as well as the emission formation of particulate matters (PM) and nitrogen oxides (NOx). Due to this above-mentioned reason, the combustion of diesel fuel acts as a toxic emission resource released into the environment. It is thus necessary to question that how to use this type of engine with minimizing emissions of PM and NOx without affecting significantly the thermal efficiency of engine. Involving with the use of premixed charge compression ignition (PCCI) mode is considered as an advanced combustion mode for the strategy of NOx and PM emission reduction. In this article, the combination of fuel injection under high pressure applied to PCCI combustion mode was assessed on the basis of the emission characteristics of NOx and PM. The changing trends of NOx and PM emissions were thoroughly analyzed to have a comprehensive overview on the effects of fuel injection pressure (IP) on controlling emissions of NOx and PM when DEs were operated under PCCI combustion conditions. In closing, it is worth mentioning that the increase in fuel IP was demonstrated to improve the engine performance, while the emission control based on PCCI combustion strategy was found to bring several benefits for the control and management of combustion process under lower temperatures compared to conventional DE. [ABSTRACT FROM AUTHOR]

Currently, the rapid rise of population and industrialization has resulted in a release of a large amount of solid waste into the environment and a huge consumption of energy. Therefore, solving these two urgent problems relating to the environment and energy simultaneously needs paying much attention to. Among the solid waste sources, the scrap tire (ST) is considered as the most common in the world, the recovery and utilization of this ST source for the purpose of energy production should be thus believed as a good initiative because this advanced solution has a significant contribution to the partial reduction of the energy crisis and environmental pollution. The scrap tire pyrolysis (STP) technology is known as an effective solution for decomposing rubber materials at high temperatures without the involvement of oxygen. This article focuses on an overview of the pyrolysis technology to produce STP-based products such as gas, char, and liquid fraction. The STP-based products are analyzed and assessed to clarify their valuable properties and to use these products for various applications. As a result, gas fraction with 29.9–42.1 MJ/m3 of calorific value could be used for commercial purpose, while the char fraction is suggested as a potential composition for active carbon production due to carbon fraction higher than 80%. The physicochemical properties of liquid such as approximately 1.5 for H/C ratio and around 40 MJ/kg of calorific value are demonstrated to be suitable and potential fuels for the areas of the industry, the construction, and for diesel engines. [ABSTRACT FROM AUTHOR]

Diesel engines have considered as the popular internal combustion engine used in transport, agriculture-forestry-fishery, and power generator due to their utility. Stringent norms of the environment, increasing demand of energy, and depleted fossil fuel have led to looking for an alternative and renewable energy source. Jatropha oil-based fuels were considered as the appropriate energy source in the future to replace traditional diesel fuel. However, some problems such as coke and deposit formation resulting in the changes in fuel spray characteristics and engine performance were encountered because of high kinematic viscosity and density of straight Jatropha oil when used for diesel engines. The aim of this study is to improve the drawbacks of Jatropha oil by heating before being fueled a 4-stroke–4-cylinder diesel engine. The deposit formation around the injector tips, fuel spray characteristics (including penetration length and cone angle), combustion, and emissions of the above-mentioned diesel engine running on preheated Jatropha oil and diesel fuel after 300 h were practically measured and compared to the first hour (0 h). After completion of the long-term 300 h test, some results of the test engine fueled with preheated Jatropha oil such as a huge amount of deposits around the injectors tips resulting in partly clogging the nozzle holes and increasing penetration length to 10.52%, a decrease of 30.73% for engine power and 7.28% for NOx emissions, an increase in 8.63% of HC and 6.96% of CO emissions were detected; meanwhile, the above parameters for diesel fuel after 300 h of test were insignificantly different from the first hour. Moreover, the element components in deposits were also thoroughly analyzed by EDS, and optical observation was assisted by SEM. [ABSTRACT FROM AUTHOR]

Vegetable oils are always considered as the potential sources since the renewable and alternative fuels have been being paid attention by all countries in the world based on the strategies of the environmental pollution reduction. The aim of this experimental study is to evaluate the effects of as-used fuels on emission characteristics, deposit formation, and lubricating oil (LO) degradation of a 4 stroke-4 cylinder diesel engine running on preheated vegetable oil and diesel oil. All tests were conducted under 2000 rpm of engine speed, and 80hp of power within different periods of time depending on the test purposes. The ICP-MS analyzer was used to measure the LO quality through the parameters of kinematic viscosity, density, and metal concentrations on the basis of ASTM D5185-09 standard after every 25 hours of the test duration. Meanwhile, the emission characteristics were tested by an exhaust analyzer after every 50 hours, and deposit formation on piston crown and piston groove was evaluated by the assistance of Scanning electron microscopy (SEM) after 300 hours of the test. Besides, the thorough analysis related to the relationship between deposit formation, the degradation of the engine LO and emission characteristics were presented. [ABSTRACT FROM AUTHOR]

For the short-term use of diesel engines, biodiesel can provide a comparable engine performance to that of using fossil diesel fuel. However, some arising problems including the reduction of the engine performance, the increase in lacquer deposits, and excessive carbon blacks in the combustion chamber and in the injectors resulting in an increase in the emissions and the damage to the engine have been indicated. Deposits formed inside or outside the injector may have an adverse influence on the engine performance and the fuel injection system. In this study, a review of the formed deposits in the injector of diesel engines fueled with biodiesel was conducted. The physicochemical mechanism of the deposit formation in the injector including injector nozzles, injector holes, and injector tips was mentioned. Moreover, the test-cycles for determining the deposit formation level in the injector were also introduced. Especially, the effects of the key factors such as biodiesel components, temperature, and injector configurations on the formation level of deposits were reviewed, and the utilization of the cativation mechanism in the controlling strategy of the deposits was presented. Besides, the impacts of deposits in the injector on the spray characteristics, combustion, and diesel engine operation process were also referred. [ABSTRACT FROM AUTHOR]

Using vegetable oils as fuel for diesel engines in the long term may cause some extremely serious problems, such as an increase in toxic emission and pollutants, reduction in engine power, and degradation of lubricating oil (LO) due to deposit formation, abrasion, and wear, as well as damaged engines. In this study, the 4 stroke-4 cylinder-Yanmar TF120M diesel engine was tested the endurance during 300 h on diesel fuel (DF) and preheated straight jatropha oil to evaluate the effects of these two fuel types on the degree of deposit formation, LO, brake-specific fuel consumption (BSFC), and emission characteristics. The results showed that, although the properties of straight jatropha oil were improved by preheating at 90°C (SJO90), the degree of deposit formation for SJO90 was observed higher in comparison with DF. Furthermore, scanning electron microscopy (SEM) was used to analyze the deposits. Related to engine performance and emission characteristics, higher BSFC, unburnt hydrocarbons and carbon monoxide emissions, and lower nitrogen oxide emissions for SJO90 compared to DF were presented. About the results of LO analysis, the excessive metal concentrations in LO of test engine for SJO90 were much higher than the case of using DF. Besides, an increase in LO density and a reduction in LO viscosity also showed the degradation of LO for SJO90 in comparison with DF after test time. [ABSTRACT FROM AUTHOR]

Not only marine species, but human and nature environment have been also affected seriously as the marine environment is polluted by oil spill, heavy metal, and others. In this study, a new sorbent fabricated by adding rice straw into polyurethane foams was investigated. Oil types such as crude oil, fuel oil, diesel oil, kerosene and a solution containing Cd2+, Cu2+ metal ion were used to evaluate the absorption capacity of this new sorbent. The experimental result after 150 minutes showed that, the oil absorption capacity of new sorbent added 25% of rice straw mass and 500 μm of size was highest, correspondingly to 15.086 g/g, 13.964 g/g, 12.226 g/g, 10.746 g/g of crude oil, fuel oil, diesel oil, kerosene, respectively. Moreover, Cd2+, Cu2+ metal ion absorption capacity was 212.9 mg/l and 193.6 mg/l. Besides, the relationship between contact angles and pore diameters, oil absorption capacity and oil surface tension, SEM were considered. [ABSTRACT FROM AUTHOR]

Spilled oil has been considering as extremely serious disaster in the maritime field and oil exploration, and its effects lasted for decades, even hundreds of years. Oil spill treatment and recovery were the difficult and complicated issues due to the conditions of nature environment. In this work, rice straw- agricultural residue in Vietnam – with 205 k g/m3of low density was filled in porous polyurethan matrix in fabrication process of absorbent. The experimental results about oil absorption capacity for this new absorbent material showed that, the absorbed oil mass in case of filling 25% of rice straw mass with 0.5 mm of size was highest, equal to 12.012 g oil/ g absorbent material after 120 minutes of treatment. The result of oil absorption capacity was around 3–4 times higher than that of material fabricated by pristine polyurethan or xenlulozo/lignocellulosic. Besides, fabrication process and SEM analysis were also experimentally carried out in this work. [ABSTRACT FROM PUBLISHER]

In this study, new and efficient sorbent with density 0.2 g/cm3was fabricated by incorporating rice straw into polyurethane matrix to get an open cell structure material with high oil uptake capacity. The influences of various important factors such as amount of adding rice straw, size of rice straw particles, and adsorption time on oil adsorption capacity of new sorbent material were investigated. The results showed that the oil absorption rate occurred fast in first 15–30 min, then slowed down and reached saturation level after about 2 h of treatment. Oil adsorption capacity of the new sorbent material was relatively high, up to 12.0 g/g. In comparison with pristine polyurethane or lignocellulosic materials, the new sorbents had higher oil adsorption capacity. Some characteristics of the as-obtained sorbent, such as surface shapes and porosity, were also studied by SEM analysis. [ABSTRACT FROM PUBLISHER]

In the present situation of emergencies of energy demand, rising oil cost, exhaustion of nonrenewable energy source assets. Biodiesel as well as producer gas acquired from vegetable oil, that is, waste palm cooking oil and biomass, that is, waste bamboo leaves are likely to be designated as the promising substitute fuel. Therefore, the goal of this research is to access the reduction in global warming gases mostly NOx and smoke associated with the introduction of producer gas along with waste cooking oil biodiesel. The current investigation draws out a test of preparing biodiesel from used waste palm cooking oil at different blending proportions and its application on a dual fuel mode turbocharged direct injection diesel engine, with varying load at a fixed speed of 1500 rpm. From the experimentation, it was seen that exhaust gas temperature and brake thermal efficiency reduced while, brake specific energy consumption increased by 10.81%↓, 14.08%↓, and 46%↑ relative to diesel fuel in single fuel mode. Taking into account the emission characteristics of smoke intensity, nitric oxide lowered by 63.59%↓, 91.71%↓but on the cost of higher hydrocarbon and carbon monoxide value of 40.63%↑ and 65.71%↑ in comparison to diesel mode when loaded to the maximum limit. Hence, it can eventually be concluded that waste palm cooking oil methyl ester blended biodiesel with bamboo leaf generated gaseous fuel can partially substitute existing diesel fuel with few engine alternations. [ABSTRACT FROM AUTHOR]

The oil spillage and maritime pollution due to spilled oil have been affecting human life and the environment in the long term seriously. The methods and techniques presently used to recover oil spills must be carefully considered to avoid creating unexpected secondary pollution as well as time-consuming. Therefore, the application methods for spilled oil recovery should be available, fast responsive, economical, highly absorbing, and nontoxic for the environment. The use of absorbents originated from natural organic byproducts is considered a suitable method for treating spilled oil because of their outstanding physical properties for the sustainable strategies of environmental protection. In this review paper, the factors affecting the oil absorption capacity of the raw cellulose-originated natural organic absorbents such as the nature of absorbent and properties of spilled oil are thoroughly analyzed. Moreover, the suggestion of applications of raw cellulose-absorbents in combination with other methods was also mentioned in detail. In general, the utilization of raw cellulose-based absorbents could absorb the spilled oil with a maximum yield of around 70%, and raw cellulose-based absorbents could be only suitable for near-shore oil spills. In future work, advanced absorbents based on cellulose should be further investigated and developed to increase the efficiency of spilled oil recovery aiming to satisfy the challenges relating to the disaster of oil spills in maritime operation. [ABSTRACT FROM AUTHOR]

In addition to other renewable energy sources being used to minimize the environmental pollution and climate change as well as to satisfy the ever-increasing demands of the society on the energy, biogas is considered abundant resources for energy production. The strategies of using biogas source for internal combustion engines may be a good and potential solution for saving fossil fuel and reducing pollution emission. In this current study, hydroxy (HHO) -enriched biogas under two pathways such as dual injection and blend injection was used to fuel an SI engine aiming to assess the performance (via in-cylinder pressure and indicated cycle work) and emission characteristics (CO and NOx emissions) when the input parameters including HHO/biogas ratios, the position of butterfly valve in the intake manifold, angle of HHO injection were varied. As a result, the dual injection strategy of HHO-enriched biogas produced an advantageous distribution of H2 and CH4 in combustion chamber, which improved combustion efficiency and reduced pollutant emissions. With a fixed HHO injection duration of 2.7 ms, the dual injection led to an increase in HHO concentration at all engine loads, which improved complete combustion in critical operating conditions. Increase of HHO content led to a decrease of optimal advance ignition angle and reduced the range of its variation with engine speed. In closing, HHO addition into biogas was found to improve the engine performance, to reduce CO emission, although it also increases NOx concentration. Biogas enriched by 20% HHO was considered as the best compromise between engine performance and pollution emissions with indicated engine cycle work of 204 J/cyc, CO emission of 0.74%, and NOx emission of 1192 ppm. Moreover, the ignition maps for biogas and HHO were built to point out the optimal range of advance ignition timing for the application purpose to real experiments in the future. [ABSTRACT FROM AUTHOR]

Energy is the lifeblood of modern economies as the latter is fueled by the energy demand for everyday life production and consumption. Dubbed as the period of “green economic development,” the 21st-century witnesses new development and extraordinary advances in technologies to produce energy generating from endless sources of renewable energy found in the natural environment. Driving by the fossil fuels depletion rate forecast over the next 100 years and the dire warnings on the projected impact of climate change, Vietnam has identified energy security and sustainable energy development as indispensable elements in the country’s strategic path toward sustainability in the coming century. With the issuance and adoption of a strategic orientation for sustainable energy development through 2030 and vision to 2045, the Vietnamese government has demonstrated their commitment on priorities in ensuring national energy security, providing stable, high quality, and affordable energy supply for sustainable socio-economic development, improving livelihoods, and contributing to the protection of the natural environment. Developing in harmony among sub-sectors with synchronous and intelligent infrastructure, the renewable energy industry has reached a new level among regions around the world. The paper presents opportunities, potentials, challenges, and goals of renewable energy development in Vietnam. With comprehensive analysis and review of renewable energy forms in the period of 2020 through 2030, the authors aim to create a basis for proposing policy and economic solutions for timely and effective implementation of national energy policy goals set for 2030 and vision to 2045. [ABSTRACT FROM AUTHOR]

Energy plays an important role in economic growth and environmental protection, is an important input of many manufacturing industries, and one of the essential commodities of households. The process of industrialization and modernization is ever increasing, causing the skyrocket in demand for energy worldwide. Since, the nonrenewable energy sources are increasingly exhausted, there is a serious shortage of energy; therefore, saving and using energy effectively is extremely urgent. The application of the Internet of Things (IoT) has shown an interesting growth in production management, especially, its usage in controlling energy is emerging as an attractive concept in the future. Based on an idea about a framework to save energy in the production process, the discussion of the paper pays attention to analyzing the advantages of incorporating energy data in discrete production for production management decisions, and the approaches that enhance production management practices by this incorporation. The findings suggest that the Internet of Things solutions are state-of-the-art for decision-makers to improve their discrete manufacturing facilities in terms of energy efficiency. A further highlight reveals where practices should be located, and tools and energy data need for implementation and running, simultaneously advanced achievable benefits and related practices are also mentioned in this paper. [ABSTRACT FROM AUTHOR]

COVID-19 was labeled as a global pandemic when it caused a larger number of death cases in the world. Facing the dangerous and serious global pandemic, many countries have issued the nationwide lockdown, resulting in the shutdown in all places of social gatherings, the traffic, and industrial and manufacturing activities, causing negative impacts on the socio-economical activities. However, a noticeable reduction in NO2, CO2, and PM emissions was globally recorded although this reduction was different for each nation. In this paper, an overall picture of global PM pollution was exhibited during the city-to-nation lockdowns in the COVID-19 period. Overall, the obtained results in this current work might provide confidence to the stakeholders associated with the development of policy for air quality control aiming to achieve a significant improvement in air quality when better control strategies for air pollution are strictly executed. [ABSTRACT FROM AUTHOR]

Compressed natural gas is one of the alternative fuels for internal combustion engines as they produce less smoke and greenhouse gas emission. Understanding the combustion characteristics of compressed natural gas engines help experts to come up with better combustion chamber designs for high performance and low emission engines. In this study, three different designs of piston bowl geometry in a retrofitted compressed natural gas engine were investigated in relation to engine performance and its combustion characteristics. Three types of piston-tops including two concentric bowls and one eccentric bowl operated with two different values of compression ratio (11.5:1 and 12.5:1) were the subject of the current research. Based on the results from the experiment and simulation performed in this investigation, while differences in bowl-in-piston design did not have any significant effect on engine performance and combustion characteristics of port injection compressed natural gas engines, the authors observed a significant impact of advance ignition angle and spark plug location relative to bowl’s centerline having on the combustion process and engine performance characteristics. As a result, the application of concentric bowl-in-piston and compression ratio of 11.5:1 was found to yield the lowest brake specific fuel consumption and the highest brake power. The particular outcome presents a potential strategy for the combination of piston-top shape and compression ratio in compressed natural gas engine application to attain high combustion efficiency. [ABSTRACT FROM AUTHOR]