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Particulate matter (PM 2.5 ) concentrations are a serious human health concern and global models are the common methods for PM 2.5 particle estimation disregarding the local changes and factors. In this study, a polynomial model for PM 2.5 particles prediction was proposed to examine the correlations among PM 2.5 , PM 10 , and meteorological parameters. The study was carried out in the north of Iraq including two provinces; Kirkuk and Sulaymaniyah. The data gathered from different sources. Two datasets have been used, collected during July 2019 and February 2020. To test our methodology, the model was applied on a small subset of the study area (5.6 km 2 ) inside the Kirkuk province. Datasets (observation and ground truth) were utilized to examine the model. Based on the July 2019 dataset, the mean local R 2 values were estimated at 0.98 and 0.97 in the north part of Iraq, and inside the Kirkuk province (the small subset), respectively. While based on the February 2020 dataset, the mean local R 2 values were estimated at 0.98 inside the Kirkuk province. High values of prediction accuracies were obtained by 82% and 96% in July and February, respectively. Moreover, our findings highlighted that the health impacts and air quality varied from moderate to unhealthy in the region.

Due to the upsurge of awareness of the depletion of fossil fuel feedstock and environmental issues, biodiesel has become a more attractive choice. Biodiesel's productivity is deemed a fruitful and significant research field since its relevance obtains from the increased oil prices and environmental benefits. This paper presents a study of Alfa waste cooking oil used to produce biodiesel oil via the transesterification process. The investigation includes various variables such as transesterification time, catalyst ratio, temperature, and biodiesel yield. Two catalysts (NaOH and KOH) have been utilized in this study. The engine test was carried out at constant load with increasing speed to compare different fuels' performance relative to mineral diesel. The produced biodiesel was categorized according to ASTM D6751. The highest conversion and yield of biodiesel in the transesterification method were scrutinized using the KOH catalyst compared to the NaOH catalyst. The maximum conversion and yield of biodiesel are 97.76 and 94.4%, respectively, with optimum operating conditions of 60 o C reaction temperature, 3 hours reaction time, and KOH catalyst at 4% weight. Consequently, the engine test outcomes revealed similar biodiesels trends compared to diesel in terms of engine brake power and brake specific fuel consumption with increasing engine speed.

Nowadays, one of the major problems that can face humankind is the water pollution. In this regard, making this natural resource a fresh and unpolluted is a major social and economic concern. However, a great attention has been given for the removal of organic pollutants discharged within wastewater by using advanced oxidation processes (AOPs) based on generation hydroxyl radicals. Among these, Ozone-Fenton (O3/H2O2/Fe2+) process used in this study as AOPs to remove chemical oxygen demand (COD) from Disperse Blue 79 (DB 79) dye in wastewater. Also, the effect of various experimental parameters such as ozone mass flow rate, mole ratio (mole H2O2/mole Fe2+), and reaction time on the COD removal efficiency of DB 79 were studied with constant initial concentration 60 mg/L of DB 79. Based on the results obtained in this study, the maximum COD removal efficiency was 85% achieved at optimum operating parameters are 288 mg/L. h ozone mass flow rate, 33.53 mole ratio (150 mg/L H2O2, 20 mg/L Fe2+), and 60 min reaction time. All Ozone-Fenton experiments were performed using Jar test apparatus at room temperature (23°C ∓ 2) and atmospheric pressure (1 atm). Finally, Ozone-Fenton offered an effective solution as AOPs for degrading pollutant especially DB 79 discharged within wastewater from various industrial processes.

This experimental study explores the effect of using compound technique (passive techniques (packing the shell side with small cylindrical aluminium pieces) and active techniques (air injection or bubble generation) were securitized. It is conducted for both configurations (parallel and counter) flow with applying both techniques (compound) at the same conditions in a double pipe heat exchanger. The main objective of this study is to indicate the effect of employing the two techniques simultaneously and compare the outcomes without and with the passive (packing) method under the same conditions. The heat transfer of heat exchanger in terms of cost and size has been. For this purpose, the test rig is prepared by designing and making a suitable heat exchanger equipped with flow meters and thermocouples for measuring flow rates and temperatures (Tin and Tout) of both fluids (hot and cold). The hot fluid is heated in a small tank by electrical heater with temperature controller from (TEquipment). The results show that the performance parameters of the heat exchanger enhanced about (15%) for case of applying the both techniques together and (25) % for case of using active method only.