VOLUMES AND ISSUES

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Summary:
This study investigates the spatial and temporal changes in groundwater levels and quality in the Palas Basin, a relatively-pristine semi-arid agricultural basin in Türkiye. Although groundwater is solely used as irrigation and drinking-potable water resource throughout the basin, measurements regarding the dynamics and quality of groundwater were quite rare. The analyses were based on data collected from 12 water quality monitoring wells and 15 groundwater level monitoring wells during June 2019-May 2020. Water samples were analyzed for pH, electrical conductivity, temperature, nitrate, nitrite, ammonium, total nitrogen, total hardness, alkalinity, chloride, sulfate, phosphate, total organic carbon, calcium, magnesium, sodium, potassium, and arsenic. Data analyses included hydrogeochemical analysis and multivariate statistical analysis such as principal component analysis and cluster analyses. Results showed that water quality in the basin is mostly controlled by natural factors, however, anthropogenic impacts from agriculture activities were apparent in some regions. The basin shows significant changes in water levels throughout the year due to irrigation activities. The groundwater quality was classified as either Ca-Mg-HCO3 and Ca-Mg-SO4 type. In the majority of the basin, water quality was suitable for irrigation and drinking water uses, however, a few sampling sites had very high electrical conductivity, sulfate, nitrate, and arsenic levels. The high levels of nitrates were detected in areas, where agriculture is intense, indicating that agricultural activities might be affecting water quality. High sulfate, electrical conductivity, and arsenic levels could be related to the hydrogeological setting of the basin. This study showed that agricultural activities and natural factors were effective on the hydrochemical characteristics of Palas Basin.

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Summary:
In this study, it is aimed to gain good characteristics that can directly affect daily life with more environmentally friendly, economical and performance fuels. For these purposes, acetone has been added to the fuel. Since acetone has a high vapor pressure, it is aimed to increase engine performance by taking advantage of its volatility. It is thought that emissions will also improve with increased engine performance. The experiments were carried out using a heavy-duty engine with a displacement of 11.670 cc. Engine performance and emission values were investigated at 100, 200 and 300 Nm partial loads and at 600 rpm constant engine speed by adding 5% and 10% acetone to diesel fuel. The results were compared with pure diesel fuel. Compared to the pure diesel fuel, the BTE value of A5D95 fuel was observed to be 3.28% and 2.60% better, respectively, under 100 and 200 Nm load, while the BTE value of A10D90 fuel was 0.23% and 0.05% worse. Compared to the pure diesel fuel, the BTE value of A5D95 fuel was observed to be 3.28% and 2.60% better, respectively, under 100 and 200 Nm load, while the BTE value of A10D90 fuel was 0.23% and 0.05% worse. Since there was an unexpected decrease in the BTE value of pure diesel under 300 Nm load, only A5D95 and A10D90 fuels were compared at this load. It was found that the BTE value of A5D95 fuel under 300 Nm load was 0.65% higher than A10D90 fuel. While 10% acetone additive A10D90 fuel could not have a positive effect on efficiency, it was determined that A5D95 fuel with 5% acetone additive was more efficient than other fuel types at all loads. When the emission rates of D100, A5D95 and A10D90 fuels are evaluated according to the power they produce under 100, 200 and 300 Nm loads, the CO emission rate of A5D95 fuel is less than that of pure diesel at other loads except 100 Nm load. However, the NOx ratio was higher at all loads. These results support the higher efficiency of A5D95 fuel compared to pure diesel. Other results are discussed in detail in section 3.

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Summary:
This paper presents an optimizaton study on a heat exchanger tube inserted with circular rings by using numerical analysis results. Pitch length (P), inner diameter (d) and thickness (t) of the rings are considered as factors to be optimized. Water is selected as working fluid and the tube is considered under constant heat flux and turbulent flow condition. k-ε RNG turbulent model is used to simulate the turbulent flow thorugh the tube. L9 design of experiment model is used to reduce the number of numerical runs which is proposed by Taguchi method. The optimization study is conducted as single and multi objective optimization by using Taguchi method and Grey relation analysis. Furthermore, the contribution effects of the considered parameters on the Nu and the f result are revealed by ANOVA. Numerical resutls showed that the Nu and the f increases as the P, the d and the t decreases. It is found that the most effective parameters on both the Nu and the f is inner diameter of the rings. For the single-objective optimization, the highest Nu and the lowest f is obtained with the tube configuration that are found as the P of 50 mm, the d of 10 mm and the t of 5 mm and the P of 200 mm, the d of 15 mm and the t of 3.0 mm, respectively. The P of 50 mm, the d of 15.0 mm and the t of 5.0 mm presents the best thermal and hydraulic performance according to the multi-objective optimization study.

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Summary:
Air quality measurement is the most important parameter of ambient air as it relates to harmful causes and effects on human health. Street parking causes high levels of air pollution due to the running of vehicle engines. The study presents measurements of CO and NO2 air pollutant levels in on-street parking lots conducted at his two different locations on Somba Opu Street, Nusantara Street, Masjid Raya Street and Jendral Sudirman Street in Makassar city with a different vehicle intensity and different layouts have been linked to occupancy using a simple linear statistical regression test. The results show that the analysis also showed that β = 0.71 (p<0.001). This means that a 1% increase in occupancy increased CO by a standard deviation of 0.71. The effect of occupancy on NO2 is also relatively high (β=0.83, p<0.001). These results indicate that the role of vehicle occupancy on roads causes rapid increases in CO and NO2 in the environment.

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Summary:
The aim of the present work was to the preparation of biodiesel from sunflower oil and methanol by the transesterification reaction in the presence of some ionic liquid catalysts. The yield was 98% using a 1:5 molar ratio of oil to alcohol at 55°C and in the quinoline-based ionic liquid catalyst. Important fuel exploitation properties of B20 and B50 fuel blends had been investigated. Based on the obtained results is noted that the fuel blend B20 and B50 have greater potential for diesel engines than, B100 and fossil diesel. The best result was demonstrated B20 fuel blend among the studied fuels.

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Summary:
Changing precipitation and temperature patterns due to climate change, shift ecological niches which pose a challenge for species. Furthermore, it is still unclear that if climate change faster than the speed of the species to move to more suitable environments. Climate Envelope models are used extensively in this matter to predict species geographical distribution. In this study, climate data and animal movement strategies integrated into the environmental niche model to analyze the successes of the species that have different movement strategies under the changing climate conditions. Four different movement strategies are formulized; lazy knowledge strategy (LKS), lazy no knowledge strategy (LNKS), proactive knowledge (PKS) and proactive no knowledge strategy (PNKS). In this study, mean annual temperature and annual precipitation data gathered for the RCP8.5 scenario from the HadGEM2-ES GCM model at a 10-minute resolution. Results show that the PKS has the highest survival rates which makes it the most successful strategy. Furthermore, the species with knowledge had performed higher survival rates than the species without knowledge due to their skill to find the most suitable cells around them. One-Way Anova test confirmed that there are significant differences between the strategies. Moreover, the analysis suggests that the species with knowledge of their environment have the most successful strategies for facing the climate change

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Summary:
CONTENTS
- Hydrogeochemical Characteristics and Groundwater Quality Assessment of a Relatively- Pristine Agricultural Basin (Palas Basin) (F. D. Çelik, Ö. Karadeniz) (1-11)

- Experimental Investigation of the Effect of Acetone Additive to Diesel Fuel on Engine Performance and Exhaust Emissions at Partial Loads (V. S. Kül, A. D. Coşkun, S. O.) (12-18)

- Numerical and Optimization Study on a Heat Exchanger Tube Inserted with Ring by Taguchi Approach (T. Dağdevir) (19-27)

- Assessment of CO and NO2 Pollutants Concentration in the 28-32 Parking Area and its Relation to the Occupancy Percentage in the City of Makassar, Indonesia (S. Yunus, A. Yasin) (28-32)

- Testing of Some Ionic Liquids at the Synthesis of Biodiesel (I. Mamedov, M. Musazade, H. Rustamova, O. Javadova, N. Azimova) (33-36)

- Climate Change and Animal Movement Integration in the Environmental Niche Model
(H. E. Kışlıoğlu, I. Vera, G. Di Lallo, R. Hissink) (37-41)