Experimental study on the ability of different biogas level dual fuel spark ignition engine: Emission mitigation, performance, and combustion analysis

The major aim of the research is to investigate the ability of biogas as an alternative fuel for gasoline-powered Spark Ignition (SI) engine. In this study, biogas/gasoline fuel mixtures containing different ratios of biogas, gasoline, and biogas were tested in an SI engine with an increased compression ratio at different engine loads and constant engine speed. According to the comparison with gasoline, the utilization of biogas generally decreased the Brake Thermal Efficiency (BTE), while the Brake Specific Fuel Consumption (BSFC) rose. The lowest BTE and the highest BSFC were obtained with 100% biogas. Compared to gasoline, a decrease of 16.04% and an increase of 75.52% were observed, respectively. On the other hand, the use of biogas has improved all emissions. The best emission values were obtained with 100% biogas. Compared to gasoline, Carbon monOxide (CO), HydroCarbon (HC), and Nitrogen Oxide (NOx) emissions decreased by 56.42%, 63%, and 48.96%, respectively. Finally, according to the results of the combustion analysis, the peak pressures were reduced with the utilization of biogas, and the position of the peak pressure shifted by 2 degrees to 3 degrees Crank Angle (CA). Compared to gasoline, the lowest pressure was obtained with 100% biogas, resulting in a reduction of approximately 24.69%

Response surface methodology-based parameter optimization of single-cylinder diesel engine fueled with graphene oxide dosed sesame oil/diesel fuel blend

In this study, an experimental study was carried out to determine the effects of adding different amounts of graphene oxide (GO) on engine characteristics to a single-cylinder diesel engine operating with 30% sesame oil (SO) + 70% diesel fuel mixture. After that, an optimization was carried out with response surface methodology (RSM) to determine optimum operating conditions at different engine loads. Experimental results showed that GO nanoparticle is a good addition for diesel–biodiesel blends to enhance the performance and reduce emissions. The most appropriate amount of GO is between 75 ppm and 100 ppm for the performance characteristics. The optimal amount of GO for power is 75 ppm, while for brake-specific fuel consumption (BSFC) and exhaust gas temperature (EGT) it is 100 ppm. In addition, the maximum GO amount of 100 ppm is the most suitable for carbon monoxide (CO) and hydrocarbon (HC), and 75 ppm GO amount is the most appropriate for nitrogen oxides (NOx). On the other hand, optimization results revealed that 100 ppm GO at 1950 W load was optimum conditions for all responses. The responses that emerged under optimum conditions were 1746.77 W, 968.73 g/kWh, 259.8 ?C, 0.0603%, 23.13 ppm and 185.61 ppm for power, BSFC, EGT, CO, HC, and NOx, respectively. According to the validation study, the error between the optimum and experimental results is 4.69% maximum. According to the findings of study, it can be concluded that the RSM model can successfully model a single-cylinder diesel engine and thus save time, and money. © 2022No financial support was received from any institution or organization for this study

The study of 5-11 year-old children’s language development levels who are attending special education ınstitution with mental retardation diagnosis

İlk yıllar, çocuk gelişiminin hızlı ve kritik olduğu yıllardır. Bu dönemde temeli atılan gelişimlerden biri de dil gelişimidir. Dil gelişimindeki gecikme ve sorunlar çocukların ileriki dönemde akademik başarılarını ve toplumsal uyumunu oldukça etkilemektedir. Bu nedenle çocukların dil gelişim düzeylerinin belirlenip gerekli müdahalelerin zamanında yapılması önemlidir. Zihinsel engelli çocuklar için erken müdahale ve diğer gelişimlerini etkileyen dil gelişim düzeylerinin belirlenip eğitim programlarının bu doğrultuda hazırlanması elzemdir. Bu araştırmanın temel amacı, özel eğitim kurumuna devam eden 5-11 yaş grubu zihinsel engelli çocukların kelime dağarcığını incelemek ve çocukların kelime dağarcıklarının gelişimine yaş ve cinsiyetin etkisini belirlemektir. Tarama modelinde olan araştırmanın çalışma grubunu 2009-2010 eğitim-öğretim yılında, Konya il merkezindeki özel eğitim kurumlarında öğrenim gören 5-11 yaş grubu 80 çocuk oluşturmaktadır. Araştırmada çocukların ifade yeteneği ve kelime dağarcığının zenginliğini ölçmek için hazırlanmış olan Limbosh ve Wolf’un “Lügatçe ve Dil Testi” kullanılmıştır. Verilerin analizinde betimsel istatistiklerin yanı sıra Mann Whitney U ve Kruskall Wallis H Testleri kullanılmıştır. Araştırma bulgularına göre zihinsel engelli çocukların Lügatçe ve Dil Testi’nde yer alan nesne ve canlı resimlerinden en fazla oranda balık, ev, makas, bıçak, el, kaşık, çatal, top, çiçek, şemsiye kelimelerini; en az oranda ise kaktüs, raf, büzgü, borazan, lokomotif, yelken, tıpa, dümen, sümüklü böcek, saksı kelimelerini bildikleri gözlenmiştir. Çocukların kelime dağarcıklarında yaşa göre anlamlı bir farklılaşma gözlenirken cinsiyete göre bir farklılaşma gözlenememiştir.Children’s development in the early years is very fast and critic and language development is founded during these first years. Language delays and problems in development affect children's academic achievement and social adaptation in the following years. For this reason, it is important to determine children's language development levels and interfere in the necessary interventions on time. Early intervention and identification of their language development levels affecting other development fields and preparing training programs accordingly are extremely important for children with mental disabilities. The main purpose of the present study is, to examine the vocabulary of 5-11 year-old children with mental disabilities who are attending special education institutions and to determine the effect of age and sex on children’s vocabulary development. The study, which is in screening model, formed with a sample consisting of 80 children that are 5-11 year-old and studying in private educational institutions in the city center of Konya during the academic year 2009-2010. "Vocabulary and Language Test" which was designed by Limbosh and Wolf is used in the study to examine children’s ability to express themselves, and to assess the richness of their vocabulary. In addition to descriptive statistics, Mann-Whitney U and Kruskal-Wallis H tests were used in the analysis of the data. According to research findings, it is observed that mentally retarded children knew the words fish, home, scissors, knife, hand, spoon, fork, ball, flower, umbrella more likely at most rate; and cactus, shelf, pucker, trumpet, locomotive, sailing, stopple, steer, slug, and pot more likely at the least rate regarding the objects and pictures within the Vocabulary and Language Test. While children’s vocabulary differ significantly in terms of age, no significant difference was seen regarding gender variable

AC elektro-ozmatik akış tabanlı mikro tellerle sağlanan mikro akışkan karıştırıcının incelenmesi

Cataloged from PDF version of article.Thesis (M.S.): Bilkent University, Department of Mechanical, İhsan Doğramacı Bilkent University, 2018.Includes bibliographical references (leaves 55-61).AC electrokinetics (ACEK) is useful technique for providing species manipulation and liquid transportation. This method is applicable to many fields like cell separation, synthesis, pumping, mixing in microfluidics technologies. Mixing in micro-scale is very problematic issue due to the domination of surface forces over inertial forces. For acquiring complete mixing, extended channels or longer time is needed. To accelerate mixing, active and passive micromixers are presented in the literature. Among active micromixer types, ACEK-based micromixers are preferred techniques due to their advances in preventing electrochemical reactions and electrolysis. In this thesis, micromixer based on AC electroosmosis (ACEO) around micro rods is introduced. In this study, mixer performance is evaluated according to variable rod configurations, two different surface material and ow rates. Both computational modeling and experimentation are handled. Easy and cheap fabrication with commercially available metal wires is adopted. By introducing 3D electrode pairs, 3D vortex profile is presented and the most in uential configuration is discovered.by Hatice Dilara Uslu.M.S

Improving the combustion process by determining the optimum percentage of liquefied petroleum gas (LPG) via response surface methodology (RSM) in a spark ignition (SI) engine running on gasoline-LPG blends

In the current research, it is aimed to determine the optimum ratio of liquefied petroleum gas (LPG) to be used efficiently in terms of performance and emissions in a spark-ignition (SI) engine running on gasoline-LPG blends with response surface methodology (RSM). To create the RSM model, LPG and engine load were selected as input variables, while performance and emission responses affected by input variables were selected as brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), carbon monoxide (CO), carbon dioxide (CO2), and hydrocarbon (HC). Analysis of variance (ANOVA) supported RSM analysis was performed according to the selected factors and responses, it was found that LPG had a significant effect on all responses. Moreover, it was concluded that BSFC and BTE are the most affected responses to LPG ratio change. Also, according to the optimization results, the optimum factor levels were determined as 35% and 2400 W for LPG and engine load, respectively. According to the verification study, the maximum error between the experimental results and the optimization results was found as 3.75%. As a result, it is concluded that the SI engine fueled with LPG can be successfully modeled with low error rates by using RSM. © 2021 Elsevier B.V.No financial support was received from any institution or organization for this study

Group regulation guidance through agile learning strategies: empowering co-regulation, transactive memory, group cohesion, atmosphere, and participation

The main purpose of Computer-Supported Collaborative Learning (CSCL) is to improve academic performance through collaborative systems design. To increase the quantity and quality of interactions in CSCL and to reduce feelings of loneliness and burnout during online learning, learner group regulation should be supported. According to the literature, performance and learning motivation cannot be achieved if group communication and interactions are not adequately supported in collaborative learning. However, studies comparing traditional online teamwork and co-regulation guidance are rare. In this context, the purpose of this study is to determine the effects of experimental application designed using agile project management tools to support students' group regulation in collaborative teamwork in online environments on co-regulation, transactive memory, group cohesion, atmosphere, and participation in web programming education. 91 university students participated in this study, which was carried out in the web programming course. The application lasted 17 weeks. Qualitative and quantitative data were collected in the study, which was designed with the mixed method. As a result of the research, there was a significant difference between the co-regulation, group cohesion, and group participation scores of the students in group regulation guidance practices through agile learning strategies, according to the intervention groups. It was concluded that the experimental application had positive effects on the improvement of group dynamics. This study provides an example of how to develop co-regulation practices in online collaborative contexts

Multi-objective-optimization of process parameters of diesel engine fueled with biodiesel/2-ethylhexyl nitrate by using Taguchi method

In this investigation, the effects of fuel mixtures prepared using different proportions of biodiesel (99.5%, 98.5% & 97.5%) and 2-ethylhexyl nitrate (EHN) (0.5%, 1.5% & 2.5%) on the performance and emission characteristics of diesel engine were investigated at different loads (2000, 2500 & 3000 W). Experiments were designed using Taguchi with L27 orthogonal array (OA), and the load, % blends of EHN and % blends of biodiesel with three levels of each were taken as control parameters. Also, optimization has been performed to obtain the best combination of control parameters to optimize the response characteristics such as brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and smoke. Optimization analysis revealed that biodiesel ratio of 99.2%, EHN ratio of 1.3%, and the load of 2300 W were the optimum results for the best performance and emission values. The optimum responses according to the optimum parameters determined as 25.05%, 781.248 g/kWh, 0.085%, 20.30 ppm, 632.72 ppm, and 0.257% for BTE, BSFC, CO, HC, NOx, and smoke, respectively. The maximum error of 9.42% obtained from the validation between the optimization results and the experimental results reveals that the findings of this investigation are acceptable. © 2021 Elsevier Lt

The relationships between university students' information-seeking strategies, social-media specific epistemological beliefs, information literacy, and personality traits

Due to doubts about the reliability of information in social media environments, and the epistemological beliefs of individuals who use these media, questioning the source of information and the perception of knowledge structure, is an important research topic. A structural model was constructed to explore structures associated with epistemological beliefs (justification for knowing) and online information-seeking strategies. The model included personality traits and information literacy. Data were collected from 190 university students. PLS-SEM was implemented in the analysis of the data. Analysis revealed that there was a significant relationship between epistemological beliefs specific to social media and information-seeking strategies, and information literacy structure has a direct effect on information-seeking strategies. Agreeableness and neuroticism were related with several dimensions of social media-specific beliefs. It was found that the personality trait which has the greatest effect on online information-seeking strategies is conscientiousness

Evaluation of the effect of a new alternative fuel containing boron and hydrogen on gasoline engine performance and emission responses

In this research, the impacts of the use of a new fuel additive called octamix, which is obtained by mixing trioctyl borate as a boron source, ammonia borane as a hydrogen enhancer and ethyl alcohol, on the performance and emission values in a gasoline engine have been investigated experimentally. The experiments were carried out using four different fuel mixtures obtained by mixing octamix with gasoline at 0.5%, 1%, 2% and 3% by volume and pure gasoline at different engine load values in a single cylinder spark ignition engine. While brake thermal efficiency and brake specific fuel consumption were evaluated as performance parameters, carbon monoxide, hydrocarbon, carbon dioxide and nitrogen oxide were taken into consideration as emission responses. Experimental results revealed that using octamix higher than 0.5% was not efficient in terms of performance and emission. With the use of a fuel blend containing 0.5% octamix, overall emission and performance values improved but deteriorated with other octamix-containing fuels. According to the results, it can be said that octamix fuel is more suitable for use as a fuel additive rather than as a stand-alone fuel for gasoline engines and the use of only 0.5% octamix-containing fuel mixture is efficient. Graphic abstract: [Figure not available: see fulltext.] © 2021, Islamic Azad University (IAU)