This study investigates the dynamics and properties of non-premixed methane/air flames under three swirl numbers by segmenting flame images using the Otsu thresholding technique. Under three operating conditions, the lean blow out (LBO) and flame length, lift-off height, maximum width, flame angle, and flame pulsing displacements in terms of flame center of gravity, length, and width are measured and compared. A high-speed camera is used to record video of flames, and the image processing of frames collected from a high-speed video was accomplished by using the intermittency distribution method to quantitatively compare flame attributes. The findings show that increasing the swirl number from 0.5 to 0.7 generally has an unfavorable effect on the LBO at given fuel flow rates, and the LBO of flames under 35° (0.6 swirl number) and 40° (0.7 swirl number) swirlers has decreased up to about 15% and 40%, respectively when compared with a 30° swirler (0.5 swirl number). Additionally, observations indicate that the flame length (𝐿) and lift-off height (𝐿𝑂) drop as the swirl number rises, although the flame width (𝑊) and angle (𝛼) show an ascending tendency. Besides, flame lift-off reveals an increasing-decreasing trend with an increment in the airflow, and flame length decreases as the airflow rate increases. It was also observed that flame pulsating displacements in terms of center of gravity (𝛿𝐶𝐺), length (𝛿𝐿), and width (𝛿𝑊) increases with an increase in the fuel flow rate, and as the swirl number is increased, 𝛿𝐶𝐺 and 𝛿𝐿 lessens, while 𝛿𝑊 increases.

Among the types of renewable energy, solar energy has received more attention due to its ability to convert directly into electricity and heat, its ease of use, its possibility of storage, and its endlessness, so in recent decades, a lot of research has been done on solar energy systems in the world and in Iran. Considering Iran's potential in the field of solar energy and the country's need for this type of energy, it is necessary to locate and identify suitable sites for the use of solar energy. In this research, the potential of generating power from solar energy on the ocean coasts of south-eastern Iran has been investigated. The geographical data of the solar radiation map of Iran was used to estimate the power of electrical energy from spatial limiting criteria for the feasibility of installing photovoltaic panels at the power plant scale. Finally, the total power of electricity that can be extracted from suitable places in the region was calculated; results showed that 37.5% of the Makran area is exploitable as solar farms. With a conversion efficiency of 15% and an area factor of 70%, annual electricity production for the exploitable area is roughly 17200 GWh, which can be a driving force for the industrial, economic and social development of Makran region.

The consumption of hydrogen as an automotive fuel has been growing since the 1980s. It can be used both as a gasoline blend and as a pure fuel. All human activities involve the use of energy. Some examples are: fuels for transport and heating, electricity for various purposes, among others. It is a basic element for the production and commercialization of any goods or services and represents one of the main expenses of families. Thus, projected future trajectories for energy prices are of obvious interest to consumers and producers. The use of hydrogen generation and storage technology is an energy generation option to replace current fossil fuels, as it offers the opportunity to obtain energy with reduced environmental impacts and which does not pollute the environment. In this work, TiO2 fibers were obtained by the electrospinning technique and used as catalysts in the photodecomposition of water-ethanol mixtures for the production of hydrogen. The X-ray diffraction technique (XRD) was used to characterize the synthesized catalysts, the BET method provided measurements of the specific area, and scanning electron microscopy (SEM) analyzed the morphology of the samples. The results indicate that the fibers that contain the anatase phase in greater proportion have a high surface area and were the most effective in the production of hydrogen.

The world is searching to find alternatives to fossil fuels. The main criteria for an ideal future fuel are cleanliness, inexhaustibility, and independence from foreign control. Hydrogen fuel has indicated all these characteristics and is promoted worldwide as an environmentally friendly replacement for fossil fuels in the industrial and transportation sectors.

Sarawak is a state in Malaysia that has many potential sites for hydropower dams as Sarawak houses many hilly areas which are yet to be developed. As a result, many hydropower dams were proposed in Sarawak. This paper reviews the environmental and social impacts of hydropower projects in Sarawak. The murky river waters of Sarawak contributed to a high level of sedimentation in the hydroelectric plant reservoirs which increases the emission of greenhouse gases through mineralization and indirectly affects the lifespan of a hydroelectric plant. The ecosystem is adversely affected by the loss of trees, destruction of habitat for flora and fauna, and the narrowing of rivers due to sedimentation. The construction of hydropower plants forces nearby indigenous communities to relocate, which are given compensation by the Sarawak government. The issues behind the relocation process are explored in this paper with further details. The communities that are affected by the construction of the hydropower dams will have to be displaced from their original lands; thus, the approach by the government to compensate the affected locals in Sarawak is explored in this paper.

External-cooling indirect evaporative coolers with different configurations and working air sources are incomprehensively analyzed and compared so far. This paper investigates the mechanism and theory of operation of indirect flat-panel evaporative coolers based on X-analysis. Then, based on the second law of thermodynamics analysis, the entropy production rate of the flat-plate heat exchanger of the cooler is calculated. As a result of this analysis, the optimal energy efficiency-evaporation efficiency and cooling capacity values are presented in terms of effective parameters in the design.

Coronavirus Disease 2019 (COVID-19) has been destructive in various sectors of Malaysia. In the renewable energy sector, Malaysia thrives in harvesting solar energy, biomass energy, and hydro energy, but despite years of development, the impacts of COVID-19 on these fields remain significant. This paper reviewed, analyzed, and summarized the effects of COVID-19 on the renewable energy sector in Malaysia. According to reviews, solar energy projects experience postponements as the import of solar panels is halted. At the same time, biomass saw its productivity reduced as workers were sent home as a measure to curb COVID-19. The same can be seen with the hydroelectric dams, where a single case may form a cluster which, once again, puts the entire project on hold. These are just some examples of the disastrous impact of COVID-19. However, there are positive impacts as well. The reduction in CO2 emission and the investment in the renewable energy sector once fossil fuel drops its price are the same example testimonies. The future of the renewable energy sector after COVID-19 and the lessons learned from the impacts of COVID-19 are reviewed and presented in this paper as well.

Improving perovskite solar cell (PSC) efficiencies would not have been possible without discovering and incorporating novel materials. More significant than materials usage is the compatibility of various material components in the entire device. Charge transport materials have been at the heart of this discussion to decide a PSC's functioning fundamentally. This review highlights various high-efficiency examples using alternate charge transport materials, bringing us one step closer to commercializing this technology. The article also elaborates on recent innovations in Bismuth and Copper-based PSCs. These are possible candidates to replace the conventional materials used in a standard PSC and affirmatively yield favorable results through extensive research.

These days, one of the major threats in the world is climate change. It is already proven by a large number of strong evidence that human activities are responsible for these sudden changes. It is expected that in the future mankind will witness more severe consequences of climate change on the amount of precipitation and temperature levels in different regions of the world, and as a result of that, more both physical and economic water scarcity is anticipated to be seen. Each year food production industry produces a considerable amount of greenhouse gases which are the number one factor for global warming. By fluctuations in the groundwater, surface water, CO2 fertilization, and extreme weather conditions such as floods and droughts, a drastic impact on agricultural practices is expected to occur in Iran if the current trends are not slowed down or reversed. Any disturbance in food security and quality could lead to malnutrition, food-borne illnesses, or even death. Crop cultivation and livestock have their own unique impact on the total emitted GHGs. Given this, in this study, we analyzed the food production (both animal-based and plant-based), consumption, and global warming potential (CO₂e) of 11 main dietary categories in the Iranian food industry from 2010 to 2019. Moreover, the population growth in the decade was included in the study. The results of this article revealed that vegetable consumption faced a downward trend in the decade while animal protein sources remained almost intact and animal-based food items produce a considerably higher amount of greenhouse gases than plant-based dietary options.

Energy is a sector of production of considerable interest. Today's era is particularly dependent on energy. Both continuous technological upgrading and the increase in living standards require ever-greater energy security. Many countries in the world are formulating their policies in order to secure energy resources. Energy security is one of the most important objectives of any country in the international economic system. All countries are trying to secure energy resources whether they are endowed or through trade. However, the main issue that arises is the production of energy. Energy production has a direct and indirect impact on a country's economy. It is therefore essential to properly investigate those factors that determine energy production. What are those factors determining energy production? There are many factors that can determine energy production. This study will attempt to set an analytical framework that can analyze the factors that determine energy production. The methodology applied is the construction of a composite index (CI).