CO2 Emission Values Research Articles

Design and Techno-Economic Analysis of Hybrid Power Systems for Rural Areas: A Case Study of Bingöl

Today, many factors, especially the increasing world population and developing technology, increase the energy needs of people and societies day by day. The fact that fossil resources are both in danger of depletion and have negative environmental impacts has directed countries to new resources. The study focuses on the effective use of renewable energy sources (RES) and the evaluation of waste to meet the electricity and heat energy needs of Yiğit Harman Village, located in the Solhan district of Bingöl Province. For this purpose, a renewable-energy-based combined heat and power system (CHP) was designed using HOMER Pro software (version 3.14.2, Homer Energy LLC, Boulder, CO, USA). Solar, wind, biomass, and hydrogen energy sources were used, considering the resources of the region. Using the designed model, the entire electricity energy requirement and half of the heat energy were completely met by the region’s available RESs. In addition to the technical analysis, economic and environmental analyses were also conducted, and LCOE, NPC, and CO2 emission values were obtained as 0.271 USD/kWh, USD 739,772, and 37,958 kg/yr, respectively. These results indicate that with an investment of approximately USD 7000 per household, the electrical and thermal energy needs for 25 years can be met.

A comprehensive assessment of mechanical and environmental properties of waste basalt powder-modified high strength mortars exposed to high temperature

Waste Basalt Powder (BT) is a stone cutting workshop waste. The BT was recycled in the high strength mortars by Portland cement (PC). High temperature performance of the mortars were determined up to 800 ºC by in terms of weight and strength losses. The global warming potential (GWP) and Primary Energy (PE) of the mortars were calculated by Life Cycle Assessment (LCA) for the mortars and their environmental impacts were evaluated. GWP and PE decreased up to 23.9 % and 22.4 % in BT-containing mortars compared to the control group, respectively. Lower CO2 emission and PE values were determined in all the BT-containing mortars compared to the control group. Mortars containing 15 % BT had 9.92 % higher compressive strength than the control group with 14.35 % and 13.44 % lower GWP and PE values, respectively. The optimum BT content is 15 % in terms of strength, high temperature resistance and environmental impact. As a result, it is possible to successfully recycle BT material in the production of high-strength mortar that is more resistant to high temperatures.

Employ Mathematical Modeling to Summarize, Analyze, And Predict the Relationship Between Carbon Dioxide and Temperature, Location, And Other Factors.

Fluctuations in the amount of greenhouse gases (GHGs) are affected by a variety of factors, both natural and artificial. Natural factors, such as volcanic eruptions and changes in the intensity of solar radiation, can cause fluctuations in greenhouse gases. However, in recent years, human activities have surpassed natural factors and have become a major driver of climate change. During the industrial revolution, the widespread use of fossil fuels, large-scale deforestation and emissions from factories caused irreversible damage to ecosystems. Rising global temperatures are destroying natural ecosystems around the world and are a potential threat to human survival. In this paper, we systematically examine and analyze the main sources of greenhouse gas emissions, explore the factors contributing to air pollution, and evaluate the specific impacts of these changes on global warming. We analyze the relationship between global warming and different factors (economic development, clean energy, and CO2 emissions) by using both one-way linear regression models and multiple linear regression models. A quadratic linear regression model shows that solar energy is the most promising renewable energy source. Meanwhile, using the global GDP as a criterion, we have shown that economic growth contributes to CO2 emissions. However, due to the governments having valued economic development more, the upward growth trend of the economic development curve is intensified, while the downward growth trend of the global average temperature is slowed down. Finally, we developed a multivariate linear regression model to evaluate whether using new energy sources could help mitigate global warming. Based on the previous analysis, we focus on the factor of CO2 emission. By using the linear regression model, we obtained the projected values of CO2 emissions, clean energy usage and global GDP in 2050, and the CO2 emissions in 2050 are 36.59439 billion tons, which meet the goal of carbon neutrality.

Kecukupan Ruang Terbuka Hijau (RTH) Publik dalam Menyerap Emisi Karbondioksida (CO2) dari Kegiatan Transportasi di Kecamatan Bukit Raya Pekanbaru

Green Open Space (GOS) is one of the efforts to deal with increasing GHG emissions because it has the ability to absorb CO2 emissions. Development Area IV Pekanbaru is one of the Development Areas that has the potential to produce carbon dioxide (CO2) emissions, specifically in Bukit Raya Pekanbaru District. This research was conducted to determine the number of motorized vehicles and the value of CO2 emissions produced each day, as well as the value of the capacity of GOS to absorb CO2 emissions from transportation activities in Bukit Raya Pekanbaru District. The method used is recording traffic activities to calculate the amount of CO2 emissions and calculating all public green open spaces with vegetation cover in the form of grasslands and trees with a diameter of ≥ 20 cm, as well as calculating the percentage of green open space absorption capacity. The research results obtained were that the value of CO2 emissions from transportation in Bukit Raya Pekanbaru District was 67,007,898 tons of CO2/year. Meanwhile, the capacity to absorb CO2 by public green open spaces is only 1,992.32 tons of CO2/year. The results show that public green open space in Bukit Raya Pekanbaru District in terms of absorbing CO2 emissions from transportation is still insufficient with a percentage of only 2.97%.

Effect of recycled polyethylene catalyst for Mediterranean pine seed shell biomass pyrolysis on hydrogen and methane production

ABSTRACT The present study exhibits the potential of hydrogen and methane gases production from the Mediterranean pine tree seed shell biomass over recycled polyethylene wastes as catalyst. In the study, firstly, the viscosity and density of polyethylene materials and degassing point were determined. The pyrolysis was carried out at a rate of 50 °C/min at 600°C temperature. The obtained gases were analyzed with gas chromatography device. At the last step of the experiments, solid residues were observed under an optical microscope, and their microstructures were also examined. The results showed that Mediterranean pine seed shell biomass and its mixture with low-density polyethylene may produce methane and hydrogen gases. M8 catalyst, which has one of the lowest viscosity values (0.45 gr/10 min.) and highest density values (0.950 gr/cm3) produced the highest methane and hydrogen gas yields. In the pyrolysis experiments, 38.44% CH4, 19.50% CO2 and 42.06% H2 gases were obtained from Mediterranean pine seed shell biomass. Moreover, CO2 emission values of biomass were calculated and compared with DEFRA values. The study demonstrated that, since hydrogen and methane can be obtained through the pyrolysis process, Mediterranean pine tree seed shell can be classified as a new biomass source and has potential to alternative fuel to fossil-based fuels for internal combustion engines.

Nexus between carbon stock, biomass, and CO2 emission of woody species composition: evidence from Ise-Ekiti Forest Reserve, Southwestern Nigeria

The carbon stock, biomass, and CO2 emissions in woody species play crucial roles in understanding and managing ecosystems. Understanding these aspects is crucial for sustainable forest management, conservation, and mitigating the impact of woody species on global carbon dynamics and climate change. This study examined the nexus between carbon stock, biomass, and CO2 emission of woody plant composition in disturbed and undisturbed areas in Southwestern Nigeria. The study involved the random establishment of plots in the disturbed and undisturbed areas and, in each plot, the woody plants were enumerated and identified to the species level. The results showed that total biomass (102.645 Mg ha-1), total carbon stock (51.323 Mg C ha-1), and total CO2 emission (188.354 Mg C ha-1) values of tree species in undisturbed plots were higher than the values of total biomass (70.768 Mg ha-1), total carbon stock (35.384 Mg C ha-1), and total CO2 emission (129.859 Mg C ha-1) recorded in disturbed plots. The results also revealed that total biomass (0.123 Mg ha-1), total carbon stock (0.061 Mg C ha-1), and total CO2 emission (0.225 Mg C ha-1 ) values of shrub species recorded in disturbed plots were higher than values of total biomass (0.067 Mg ha-1), total carbon stock (0.034 Mg C ha-1) and total CO2 content (0.124 Mg C ha-1) recorded in undisturbed plots, respectively. The findings showed that in undisturbed and disturbed plots of shrubs, biomass, carbon and CO2 emissions have a strong positive correlation of 1.000**. While biomass, carbon, and CO2 emission have a very strong positive correlation (0.999**) in undisturbed plots of trees, the biomass, carbon, and CO2 emission have moderate to strong positive correlations (0.458** to 0.974**) in disturbed plots of the tree. The study concluded that while biomass, carbon stock, and CO2 emission values of tree species were higher in undisturbed plots than in disturbed plots, the biomass, carbon stock, and CO2 emission values of shrub species were lower in undisturbed plots than in disturbed plots. It also concluded that the main purpose of establishing reserve forests is not totally achieved as human activities occurring in reserve forests still contribute to the increment of climate change.

Ondokuz Mayıs University drinking water treatment plant carbon footprint: emission sources and strategies for sustainability

In this study, it was aimed to calculate the carbon footprint of the drinking water treatment facility within Samsun Ondokuz Mayıs University and to determine the greenhouse gas emission sources within the facility. The total daily CO2 emission of the drinking water treatment plant is calculated as 85.05 kg CO2e/d. The analyses show that off-site CO2 emissions are higher than on-site CO2 emission values. It has been determined that the primary source of off-site emissions arises from the electrical energy consumption used in the units, constituting approximately 86.4% of the total CO2 emissions. The second important contribution parameter arises from the reaction of coagulants in mechanical mixing processes. This study emphasizes the importance of taking measures that support greener and sustainable production to reduce the current greenhouse gas emissions of the facility. In addition, calculating the carbon emissions of the drinking water treatment plant is important in informing the relevant institutions in the European Union’s efforts to achieve the goal of zeroing carbon emissions by 2050.

Post-fire soil greenhouse gas fluxes in boreal Scots pine forests–Are they affected by surface fires with different severities?

Although forest fires are one of the main natural disturbance types in boreal forests, there is limited information regarding surface fires (dominant in Northern Europe), and how surface fires of different severities could affect post-fire soil greenhouse gas emissions. The results of our study show that fire severity, time since fire and post-fire changes in soil temperature were the main factors driving soil carbon dioxide (CO2) flux (forest floor ecosystem respiration) from burned boreal forest soils. Approximately two hours after the fire, soil CO2 emissions from burned areas were significantly higher compared to pre-fire conditions, and areas with high-severity fires had significantly higher soil CO2 emissions compared to those with low-severity fires. Later (days, months) after the fire, the unburned control areas always had higher soil CO2 emission values compared to burned areas. In the case of methane (CH4), time since fire and post-fire changes in soil temperatures were the main factors driving soil CH4 fluxes. Unburned study areas were sinks of CH4 through the entire measurement period, while immediately after the fire, the burned areas turned from CH4 sink to CH4 source. For nitrous oxide (N2O) measurements, time since fire was the only factor that significantly affected soil N2O fluxes. Shortly after the fire, N2O emissions increased significantly from both low- and high-intensity study plots. Two days after the fire, post-fire soil C and N content decreased in the O-horizon and increased within the first 5 cm of the soil mineral layer, and the trend was visible both in low- and high-severity fire plots. Samples collected four months after the fire, showed similar total soil C and N content as there was before the fire.

Utilization Of Soil Ameliorant To Control Emission In Oil Palm Plantation On Tropical Peat Soil

Development of oil palm plantation areas today is increasingly leading to marginal areas, particularly on peatlands. However, development of peatland as agricultural land or as oil palm plantation has the potential to cause peatland to change from a carbon sink into a source of carbon emission. This objective of this research to determine the effect of utilization soil ameliorant to oil palm yield production and in controlling carbon emission and its impact to soil peat chemical properties. The research was conducted in Rokan Hilir district, Riau. The study was carried out in a randomized block design with three replications and three levels of soil ameliorant. The results show that application of high rate soil ameliorant significantly increase FFB yield relatively from control plot. Based on observational data for two months after first application of boiler ash, the CO2 emission was tends to decrease in plot that get the application of soil ameliorant compared to the control plot. Application of 1.5 tonne/ha/yr of ameliorant give the lowest CO2 emission value. Improvement of soil peat chemical properties by application of boiler ash as soil ameliorant also observed in this study, where the high rate of soil ameliorant significantly improves soil pH and also tends to increase total Potassium and Cation Exchange Capacity (CEC).

Development of Mass–Energy Balance Model Based on a New Process of RSF with Hy-O-CR

At present, blast furnace (BF) ironmaking is still the main process for producing hot metal in China and around the world. Under the constraint of the global goal of “double carbon”, it is urgent to carry out hydrogen metallurgical innovation for the existing BF ironmaking process with higher carbon emissions. In recent years, BF technology with hydrogen enrichment and pure oxygen has made some progress, effectively reducing carbon emissions of hot metal per tons, but it is still unable to break through the technical bottleneck of emission reduction of more than 30%. In view of this, the authors put forward an ironmaking technology of a reduction smelting furnace (RSF) that is hydrogen-rich and utilizes pure oxygen and carbon recycle (Hy-O-CR), which breaks through the technical defect of traditional BF emission reduction of less than 30% by reshaping the furnace. Firstly, the construction process of the mass and energy balance model for two main unit modules in the new process (RSF with Hy-O-CR and top gas cycle) is introduced, and then the parameter optimization under specific scenario conditions is analyzed, and the influence mechanism of several key variables on the parameters in the furnace is obtained. Finally, the emission of CO2 in the whole process is explored in the case of two typical operating parameters. The results show that after using CCUS technology, the minimum value of direct CO2 emission is 215.93 kg/tHM, which is as high as 84.58% compared with the traditional BF process. Even if the removed CO2 is counted in carbon emissions, the minimum value of direct or indirect carbon emissions is 729.85 kg/tHM, and the proportion of emission reduction can reach 47.87%. The research results show that the reconstruction of Hy-O-CR technology can change the ratio of direct reduction and indirect reduction, which greatly breaks through the emission limit of the traditional BF and provides a new reference for hydrogen metallurgy technology and a basis for further study of the optimization of RSF size.

Optimal design and sizing of a hybrid energy system for water pumping applications

AbstractOne of the ways to increase the participation and penetration of renewable energy resources is to bring down the cost of these abundant resources for easy implementation and affordability. In this paper, a generalized reduced gradient (GRG) non‐linear optimization algorithm is implemented to solve a tri‐objective optimal design and sizing of a low‐cost hybrid mix consisting of a photovoltaic (PV) power plant, biomass power plant (BPP), and battery energy system for water pumping load applications in the University of Johannesburg, South Africa considering four different hybrids of biomass‐battery, PV‐battery, PV‐biomass, and PV‐biomass‐battery. The optimization model considers available energy and battery state of charge while minimizing least cost of energy (LCOE), carbon dioxide emission (tCO2eq), and loss of power supply probability (LPSP) including carbon tax incentive and penalty. The results when compared against particle swarm optimization (PSO) show the superiority of GRG over PSO with an optimal combination of PV‐biomass‐battery mix with optimal size of the PV power plant as 360.50 kW, the BPP 181.08 kW, and the battery size of 6,553.60 kWh giving a minimal optimal LCOE, CO2 emission and LPSP of 0.018 $/kWhr (with carbon tax), and 0.016 $/kWhr (without carbon tax), 28,067.73tCO2eq tCO2eq, and 1.7%, respectively. These values give a competitive advantage compared to the unit cost and values of CO2 emission and LPSP currently in the literature.

Analysis of the Effect of Renewable Energy Consumption and Industrial Production on CO2 Emissions in Turkic Republics by Panel Data Analysis Method

This study aims to analyze the impact of energy consumption and industrial production on CO2 emissions in the Turkic Republics using the Panel Data method for the period 2000-2020. However, Turkmenistan was excluded from the analysis because the relevant data could not be accessed. Data from Kazakhstan, Azerbaijan, Kyrgyzstan, and Uzbekistan were analyzed. CO2 emission creates problems in terms of environment and sustainability and is a parameter that all countries and international organizations carefully monitor and try to reduce. Using panel data regression, this study examined whether renewable energy and industrial production and countries impact CO2 emissions. The findings revealed that as renewable energy consumption increases, CO2 emissions decrease. However, the effect of industrial production on CO2 emissions was not statistically significant. These results demonstrate that the industrial development of selected countries does not pose a CO2 emission problem. A comparison of countries showed that the high CO2 emission value for Kazakhstan was also reflected in the panel data regression findings, and among the four countries, the country effect was positive only for Kazakhstan. This study is noteworthy in revealing the effect of renewable energy consumption on CO2 emissions. To reduce CO2 emissions and gain a better understanding of the impact of renewable energy consumption on CO2 emissions, future studies should include both developing countries and OECD countries, and compare the results obtained from them.

Microbial transformation of soil organic matter under varying agricultural management systems in Ukraine.

This paper presents comparative studies on the content and structure of organic matter (OM) and the activity of microbiological cellulose destruction in three types of Ukrainian soils intensively used in agricultural production. The highest content of humus in the arable layer (4.9%), OM (410 t ha-1), and total carbon (30.9 mg C g-1 soil) was determined in chernic phaeozems, which is 2.2-2.5 times higher than in albic retisols. The soil of natural ecosystems is characterised by a high content of microbial carbon (Cmic) in the carbon fraction of organic soil compounds. In arable soils, the content and reserves of humus and soil organic matter (SOM) have decreased by an average of 1.5-2 times. The most considerable loss of humus reserves in the soil profile was identified in albic retisols (1.96-1.44 times) and the smallest in chernic phaeozems (1.27-1.81 times). During the long-term systematic application of mineral fertilisers, the Corg content decreased by 8-21% in chernic phaeozems, 12-33% in greyzemic phaeozems, and 6-38% in albic retisols. A significant difference of 2.1-8.0 times was determined regarding the number of aerobic cellulolytic microorganisms and 1.3-3.3 times in the potential cellulolytic activity of the studied soils. The high number of cellulose-destroying microorganisms is characteristic of chernic phaeozems with a high content of OM in the soil; the advantage over other types of studied soils was 1.4 times and 7.8 times for greyzemic phaeozems and albic retisols, respectively. Among the studied soil types, high values of CO2 emissions were identified in chernic phaeozems. Intensive agricultural practices in Ukrainian soils have significantly altered the content and composition of organic matter, leading to reduced humus and soil organic matter reserves. The study also underscores the importance of considering the abundance of cellulose-destroying microorganisms and their potential activity in assessing soil health and sustainability.

The impact of different compression ratios on emissions, and combustion characteristics of a biodiesel engine

<p>The current work investigated the combustion efficiency of biodiesel engines under diverse ratios of compression (15.5, 16.5, 17.5, and 18.5) and different biodiesel fuels produced from apricot oil, papaya oil, sunflower oil, and tomato seed oil. The combustion process of the biodiesel fuel inside the engine was simulated utilizing ANSYS Fluent v16 (CFD). On AV1 diesel engines (Kirloskar), numerical simulations were conducted at 1500 rpm. The outcomes of the simulation demonstrated that increasing the compression ratio (CR) led to increased peak temperature and pressures in the combustion chamber, as well as elevated levels of CO<sub>2</sub> and NO mass fractions and decreased CO emission values under the same biodiesel fuel type. Additionally, the findings revealed that the highest cylinder temperature was 1007.32 K and the highest cylinder pressure was 7.3 MPa, achieved by biodiesel derived from apricot oil at an 18.5% compression ratio. Meanwhile, the highest NO and CO<sub>2</sub> mass fraction values were 0.000257524 and 0.040167679, respectively, obtained from biodiesel derived from papaya oil at an 18.5% compression ratio. This study explained that the apricot oil biodiesel engine had the highest combustion efficiency with high emissions at a compression ratio of 18:5. On the other hand, tomato seed oil biodiesel engines had low combustion performance and low emissions of NO and CO<sub>2</sub> at a compression ratio of 15:5. The current study concluded that apricot oil biodiesel may be a suitable alternative to diesel fuel operated at a CR of 18:1.</p>

Comparison of CO2 emissions during the operation of autonomous heating systems

The issue of CO2 emissions from heat generators in autonomous heating systems is one of the most important indicators of human technological impact on the Earth's atmosphere. Heat generation is carried out by heat pumps, gas and electric boilers, and systems using solid and liquid hydrocarbon fuels. The purpose of this work is to assess the CO2 emission rate per kilowatt of thermal energy for the specified generators of heating systems based on the actual energy efficiency of heat generators in heating systems with radiator-type heating devices. The study uses official data from Rosstat RF, reports from the Ministry of Energy, the Ministry of Economic Development, current GOST standards, and regulatory documents. CO2 emission values per kilowatt of thermal energy are determined for autonomous water heating systems when generating thermal energy with air-source heat pumps (ASHP), gas condensing and convection boilers, and boilers using solid and liquid fuels. The assessment of CO2 emissions from heat generators of autonomous water heating systems showed a dependency on the structure of electricity production and transportation, climate, and the heating devices used. All these parameters vary across different countries. Analyzing data for specific countries shows that different heating units have the minimal carbon footprint.

Carbon dioxide emission estimation in different zones of the south of Western Siberia

The research was carried out in key areas of fallow land in three natural agricultural zones of the south of Western Siberia in the Omsk Oblast: steppe (Cherlaksky district, v. Preobrazhenka), forest-steppe (Kormilovsky district, v. Sosnovka), subtaiga (Tarsky district, Tara); in each zone there are three sites with fallow land of different ages: 5-10, 10-20 and 20-30 years. When comparing the intensity of carbon dioxide emission from fallow lands depending on the conditions of natural and climatic zones, it can be noted that its highest value was in the subtaiga zone (average for April-September 39.4 CO2/m2 per day), which is higher than the emission in the forest-steppe zone (14.7) and steppe zone (16.6). The maximum intensity of fluxes was observed in the subtaiga zone in August, and in the forest-steppe and steppe zones in July. One of the main reasons for this pattern was the air and soil temperature: the higher it is, the more intensive is the release of carbon dioxide. The influence of the age of fallow land on the level of soil carbon dioxide emission is observed. Younger fallows are characterized by a higher value of CO2 emission compared to older ones, so in the subtaiga zone the average seasonal emission of fallows of 5-10 years is 1.51 times higher than fallows of 20-30 years, in the forest-steppe zone - 1.46 times, steppe zone - 1.48 times.

Investigation of effects on fuel consumption and exhaust emissions by using bioethanol gasoline mixture in an engine with ultrasonic fuel system

This study compared the fuel consumption and exhaust emissions of a spark-ignition engine using a carburetor fuel system, an injection fuel system, and an ultrasonic fuel system. When using gasoline only, the ultrasonic fuel system showed a 31% decrease in fuel consumption compared to the carburetor system and a 15% decrease compared to the injection system. When adding 10% bioethanol to the gasoline, fuel consumption increased in all three systems, with the ultrasonic system showing the largest increase of 10%. Exhaust emissions were also measured, and the ultrasonic system showed a significant decrease in CO, HC, and NOx compared to the carburetor and injection systems, with the largest decrease in CO emissions. The addition of bioethanol to the fuel resulted in reducing exhaust emission values in all three systems, with the ultrasonic system showing the largest decrease in CO and HC emissions compared to the carburetor and injection systems, but with an increase in NOx emissions compared to the injection system. When comparing three fuel systems, it was observed that injection fuel systems have the highest CO2 values. Although the addition of alcohol to the fuel does not cause a significant change in CO2 emission values for injection and ultrasonic fuel systems, an increase is observed in the carburetor fuel system. Overall, the ultrasonic fuel system showed promising results for reducing fuel consumption and improving exhaust emissions.

A Multi-Airspace Model to Investigate Airflow Patterns and Carbon Dioxide Emission Sources in Deep-pit Beef Cattle Finishing Facilities

HighlightsA multi-control volume mass balance approach tested with data from cattle finishing barns.Airflow estimates were highest in the barn airspace, compared to the animal-occupied zone and manure pit headspace.Slurry CO2 emission calculations were sensitive to gas concentration differences between zones and animal numbers.Abstract. An increasing number of cattle finishing barns in the Midwest are naturally ventilated (NV) with slatted floors over deep-pit manure storages. However, there is limited gas emission data currently available for this type of cattle housing and manure storage. Emission rate measurements are particularly challenging in NV barns where there are low gas concentrations and large variations in air velocity and direction. This research explores gas emission estimation using carbon dioxide (CO2) concentrations measured at the north and south wall openings, floor, nose level, and above the manure surface in the storage pit. With these measurements, three control volume mass balances for the barn airspace, animal-occupied zone (AOZ), and manure pit headspace were used to estimate airflows between control volumes and CO2 emissions rates. In this study, the estimated airflow and CO2 emission values for two NV barns were calculated for the summer, fall, and spring seasons. Nominal airflow rates calculated between the three control volumes for each barn were variable using three different solution approaches applied in this study. There was a general pattern where airflow through the barn airspace was larger than airflow between the barn airspace and animal-occupied zone, followed by airflow through the slatted floors. The range of estimated CO2 emissions considering both barns and three solution approaches was -1.16 g/s to 29.3 g/s. Overall, while calculated airflow and CO2 emission results were variable across three solution approaches, this study provides insight on a range of CO2 emissions and airflow rates through deep-pit NV cattle finishing facilities. Further model validation would be needed prior to the use of this model for gas mitigation purposes. Keywords: Airflow, Beef cattle, Carbon dioxide emission, Deep-pit barns, Modeling.

Optimization of reinforced concrete beam using hybrid algorithms with multi-objective function as CO2 emission and cost

In this study, algorithms with two objective functions are defined considering the TS500 (2000) (Reinforced concrete structures design and construction rules) and TBDY (2018) (Turkey Building Earthquake Regulation) standards for rectangular beam design. These objective functions were determined as CO2 emission and cost. Optimizations were performed in MATLAB program using the Hybrid Algorithm of Teaching-Learning Based Optimization and Jaya Algorithm. In the case of using two objective functions, cases were created by multiplying the coefficient values found in the objective function according to the formula with the cost and CO2 emission values at different rates in order to prevent CO2 emission which is one of the biggest problems for the world. In the objective function, each rate used for CO2 and cost is implemented in a manner that increases or diminishes the impact of these values. In this way, comparisons were made between the cross-section dimensions to be formed according to not only impact rates but also the reinforcement area to be used, the CO2 emission and cost values that will arise as a result of these. Impact rates are related to cost and CO2 rate in the objective function, and the total rate is chosen as 1. Impact rates for cost are chosen as 0.1, 0.3 along with 0.5, and comparisons between the results are checked. In addition, recyclable and non-recyclable steel with different properties were used in separate analyses and the values were compared. Since the CO2 rate released by the non-recyclable steel is very high compared to the recyclable steel, the results show that the CO2 emission value is higher and this causes the objective function value to increase.

Formulating Geopolymer Mortars through Construction and Demolition Waste (CDW) Recycling: A Comprehensive Case Study

The overall amount of construction and demolition waste (CDW) is steadily increasing due to urbanization-related phenomena in metropolitan cities. Only a small fraction is recycled to produce new concrete, a practice that would avoid the exploitation of natural aggregates. Furthermore, the Portland cement production process causes the release of high values of CO2 emissions into the atmosphere, increasing the global warming potential. For these reasons, materials alternative to ordinary Portland cement (OPC) are becoming more and more widespread, such as alkali-activated materials, which, when used with recycled aggregates, could become environmentally friendly substitutes for traditional concrete. During this study, various mix designs were formulated for alkali-activated metakaolin mortars containing recycled concrete aggregates. Their properties in the fresh and hardened states were analyzed. The main problem encountered was the presence of the adhered mortar layer on the recycled concrete aggregate. This layer not only caused a detrimental effect deriving from the increase in open porosity but also activated competitive reactions which partially compromised the alkali activation of metakaolin. All these phenomena deteriorated the final compressive strength of the composites containing recycled aggregates, which after 28 days, was around 20 MPa for samples with 12.5% of replacement of natural aggregate and 15 MPa for those with 25% of replacement, corresponding to a reduction of 35% and 50% compared to the standard sample without replacement, respectively.