Developing a GMDH-type neural network model for spatial prediction of NOx : A case study of Çerkezköy, Tekirdağ

Air pollution-induced issues involve public health, environmental, agricultural and socio-economic aspects. Therefore, decision-makers need low-cost, efficient tools with high spatiotemporal representation for monitoring air pollutants around urban areas and sensitive regions. Air pollution forecasting models with different time steps and forecast lengths are used as an alternative and support to traditional air quality monitoring stations (AQMS). In recent decades, given their eligibility to reconcile the relationship between parameters of complex systems, artificial neural networks have acquired the utmost importance in the field of air pollution forecasting. In this study, different machine learning regression methods are used to establish a mathematical relationship between air pollutants and meteorological factors from four AQMS (A-D) located between Çerkezköy and Süleymanpaşa, Tekirdağ. The model input variables included air pollutants and meteorological parameters. All developed models were used with the intent to provide instantaneous prediction of the air pollutant parameter NOx within the AQMS and across different stations. In the GMDH (group method of data handling)-type neural network method (namely the self-organizing deep learning approach), a five hidden layer structure consisting of a maximum of five neurons was preferred and, choice of layers and neurons were made in a way to minimize the error. In all models developed, the data were divided into a training (%80) and a testing set (%20). Based on R2, RMSE, and MAE values of all developed models, GMDH provided superior results regarding the NOx prediction within AQMS (reaching 0.94, 10.95, and 6.65, respectively for station A) and between different AQMS. The GMDH model yielded NOx prediction of station B by using station A input variables (without using NOx data as model input) with R2, RMSE and MAE values 0.80, 10.88, 7.31 respectively. The GMDH model is found suitable for being employed to fill in the gaps of air pollution records within and across-AQMS

Effects of surface preparation with sodium hypochlorite on shear bond strength and residual adhesive of orthodontic brackets on primary and permanent teeth

Objective: To investigate the effects of surface preparation with sodium hypochlorite (NaOCl) on bracket shear bond strength and amount of residual adhesive on primary and permanent teeth. Materials and Methods: 24 permanent premolars, 12 in each group (groups I and III), and 24 primary molars, 12 in each group (groups II and IV) were included. In group I and II, 37% phosphoric acid was applied to the tooth surfaces, without using any other agent. In Group III and IV, 5.25% NaOCl was first applied. Following washing and drying, surface roughening was performed with phosphoric acid. The shear bond strengths (SBS) of the brackets bonded to the tooth surfaces was measured. After debonding, the base of each bracket was examined for adhesive remnant index (ARI) scores. Results: There were no statistically significant differences in SBS values between primary and permanent teeth with and without preparation with NaOCl(P>0.05). Mean SBS(18.55±14.98 MPa) was higher in permanent premolars subjected to surface deproteinization with NaOCl (group III) when compared with other groups, but the difference was not significant. There was no significant difference in ARI scores between the groups. Conclusions: The bond strength of orthodontic brackets or the distribution of ARI scores were similar between groups with and without NaOCl pretreatment. Hence, it can be concluded that conventional bonding procedures applied without any additional preparation to primary teeth are sufficient and the debonding of brackets didn’t cause any harm to enamel surfaces

Improvement of the Wastewater Biodegradability by Means of Photocatalytic and Wet Oxidation Processes in the Presence of Hydrogen Peroxide

In this study, the effectiveness of photocatalytic oxidation (PO) and wet oxidation (WO) processes as a pre-treatment step on improvement of biodegradability and colour removal of mixture of raw domestic and pre-treated industrial wastewaters, have been evaluated. More oxygen was obtained by H2O2 (as an oxidant in WO and PO processes) than stoichiometric demand. PO of the wastewater was carried out by illumination of the wastewater with UV lamp (at room temperature, atmospheric pressure, 16.5 h reaction time) and WO of the wastewater was carried out by means of thermal oxidation at autoclave conditions (at 118–120 oC, 1.9–2 bar, 3 h reaction time). 1 g L–1 TiO2 in PO process and 0.2 mg L–1 Cu++ in WO process were used as catalyst. The results obtained from experiments were not compared with each other due to the difference between the quality and quantity of the used catalyst and the consumed energy. Colour removal efficiency was 33 % for WO process and 77.6 % for PO process. By applying WO process, 72.7 % increase in the reaction rate coefficient describing the degradability of organic compounds in wastewater was obtained, but this value was 34.5 % in PO process

Visual mining of science citation data for benchmarking scientific and technological competitiveness of world countries

In this paper we present a study where we visually analyzed science citation data to investigate the competitiveness of world countries in selected categories of science. The dataset that we worked on in our study includes the number of papers published and the number of citations made in the ESI (Essential Science Indicators) database in 2004. The dataset lists these values for practically every country in the world. In analyzing the data, we employ methods and software tools developed and used in the data mining and information visualization fields of the Computer Science. Some of the questions for which we look for answers in this study are the following: (a) Which countries are most competitive in the selected categories of science? (i.e. Engineering, Computer Science, Economics & Business) (b) What type of correlations exist between different categories of science? For example, do countries with many published papers in the field of Engineering science also have many papers published on Computer Science or Economics & Business? (c) Which countries produce the most influential papers? This analysis is needed since a country may have many papers published but these papers may be cited very rarely. (d) Can we gain useful and actionable insights by combining science citation data with socioeconomic and geographical data

Vertrauen in Online-Bewertungen

In dieser Studie gehe ich aus kommunikationswissenschaftlicher Perspektive der Frage nach, wie sich Vertrauen in Online-Bewertungen gestaltet. Um diese Frage zu beantworten, führe ich zunächst eine umfangreiche Literaturstudie zu den bisherigen empirischen Befunden zu Vertrauen in Online-Bewertungen durch. Mithilfe einer disziplinäre und methodologische Grenzen überschreitenden integrativen Literaturübersicht identifiziere ich zunächst unzählige Faktoren, die mit dem Vertrauen in Online-Bewertungen zusammenhängen. Dabei wird deutlich, dass diese Faktoren theoretisch wenig integriert sind und sich Befunde häufig widersprechen. Auf Basis einer Theorie zu Vertrauen in Journalismus (Kohring, 2004) entwickle ich daher anschließend ein theoretisches Modell zu Vertrauen in Online-Bewertungen. Mit diesem Modell können die theoretischen Lücken gefüllt und manche Befunde der bisherigen Forschung erklärt werden. Um die weiter bestehenden empirischen Unklarheiten aufzulösen und die umfassende Belastbarkeit des theoretischen Modells zu demonstrieren, führe ich abschließend eine empirische Studie durch: Mithilfe von Think Aloud und Problemzentrierten Interviews untersuche ich Vertrauen am Beispiel von Arztbewertungen

Designing of a New Type Air-Water Cooled Photovoltaic Collector

The importance of photovoltaic-thermal (PV / T) collector systems in renewable energy technologies is increasing for combined hybrid electrical heat applications. The efficiency of photovoltaic (PV) systems varies between 5-20%. On average, 15% of the solar radiation coming to the PV panel surface is converted to electrical energy and the remainder is lost. In this study, a PV/T collector was designed using two different fluids simultaneously and its efficiency was calculated numerically. PV/T collector systems are specifically designed for agricultural production and their advantages are discussed. In this study, numerical calculations of PV/T collector with a different design have been made. The results were compared with reference to another experimental study. Two different working fluids (air and water) were used in the calculations. The system where air is used as working fluid is called Mode 1 and the system where water is used is called Mode 2. It is aimed to achieve high heat transfer by using water pipes, air ducts and fins placed under PV panels. In this way, it is aimed to produce a more stable hot air and water. In addition, in order to investigate the effect of flow on the yield, different flow rates were calculated. As a result of the theoretical analyses and calculations made in consideration of literature, the total efficiencies of air flow mode (Mode 1) were calculated as 43.2%, 46,2% and 48.7% at 0.0067 kg/s, 0.0072 kg/s and 0.0077 kg/s mass flow rates, respectively. For water flow mode (Mode 2), these values computed as 52.81%, 53.83% and 55.04% at 0.023 kg/s, 0.036 kg/s and 0.054 kg/s mass flow rates, respectively. It was found that PV / T collector efficiency increased with increasing end flow. Designed collector system is preferable in terms of effective use of energy and it can be easily applicable in processes such as hot air-water preparation, drying and greenhouse heating

Spor lisesindeki sporcuların stresle başa çıkma düzeylerinin araştırılması

Bu çalışmanın amacı; spor müsabakalarına katılan Rize Spor Lisesindeki sporcuların stresle başa çıkma düzeylerinin farklı değişkenler bakımından incelenmesi ve sonuçlarının ortaya konmasıdır. Çalışma ölçek araştırması deseninde olup, çalışmaya 207 sporcu katılmıştır. Veriler, “Stresle Başa Çıkma Stratejileri Ölçeğinin Türkçe Versiyonu” kullanılarak Google form aracılığıyla online toplanmıştır. Veri analizinde tanımlayıcı istatistiksel yöntemlere ek olarak, Tek Yönlü Varyans Analizi ve Tukey çoklu karşılaştırma testleri kullanılmıştır. Veriler, SPSS 26 lisanslı istatistik programı ile analiz edilmiştir. Sporcuların cinsiyet, yaş, spor dalı ve spor yapma yılı açısından stresle başa çıkma stratejileri ölçeği alt boyut düzeylerinde anlamlı farklar tespit edilmemiştir (p>0,05). Sonuç kullanılan değişkenlerin stresle başa çıkma düzeylerini etkilemediği belirlenmiştir. Sporcuların stresle başa çıkma stratejilerinde en fazla kendine güvensiz yaklaşımı, boyun eğici yaklaşımı ve sosyal destek arama yaklaşımını tercih ettiği görülmüştür. Anlamlı fark olmamasına rağmen ortalamalara bakıldığında sporcuların kendilerine yeteri kadar güvenmediği ve dışardan gelecek bir destek arayışı içerisinde oldukları tespit edilmiştir.The aim of this study is to determine how well student athletes attending Rize Sports High School cope with stress. The study follows a scale research design and was conducted with 207 student athletes. The Turkish version of the Stress Coping Strategies Scales was completed by participants via an online Google form. In addition to descriptive statistical methods, both a One Way Analysis of Variance and Tukey multiple comparison tests were used to analyze data. No significant difference was found in the scale’s sub-dimensions by gender, age, sport branch, and years of participation in sports (p>0.05). The variables examined were found not to affect participants’ abilities to cope with stress. It was observed that the participants mostly exhibited insecurity, submissiveness, and helpseeking. Although no significant difference was found, the averages revealed that participants did not have sufficient levels of confidence in themselves and frequently sought support from a third party

Comparison of the Accuracy of Manual and Digital Cephalometric Prediction Methods in Orthognathic Surgical Planning: A Pilot Study

Objective:To compare and evaluate the reliability of manual and digital cephalometric prediction methods in orthognathic surgical planningMethods:Ten adults (5 females and 5 males) with skeletal class III malocclusion were included. The mean patient age was 21.97 years. Pre- to postoperative changes were evaluated using paired t-test. Manual surgical predictions made by tracing on acetate paper and digital predictions made using computer software were compared with actual postoperative values using intraclass correlation coefficient and root mean square.Results:Statistically significant changes were observed in SNA, SNB, ANB, U1i-FH, and Nperp-A following bimaxillary orthognathic surgery (p<0.001). Postoperative changes in Co-A and Nperp-Pg were statistically significant (p<0.05). Comparison of manual and digital surgical predictions with actual postoperative values revealed that overbite and overjet showed the lowest agreements. Manual predictions were less accurate for points that were difficult to distinguish (Co and U6). Skeletal predictions were more accurate than dental predictions.Conclusion:Parameters with low reproducibility (Co and U6) decrease the reliability of predictions. Dental predictions were inaccurate in both methods due to the effects of intermaxillary elastics, but both methods yielded similar predictions for skeletal parameters. The impact of applying strong elastics for postoperative intermaxillary fixation should be considered when making surgical predictions