Preparation and characterization of inorganic membranes by using sol-gel techniques

Thesis (Master)--Izmir Institute of Technology, Materials Science and Engineering, Izmir, 2000Includes bibliographical references (leaves: 138-143)Text in English; Abstract: Turkish and Englishxiii, 143 leavesIn this research the preparation of ceramIC membranes for gas separation applications by using sol-gel techniques were investigated. The effects of water/alkoxide ratio, H+/alkoxide ratio on the catalysis of the hydrolysis-condensation reactions and the peptization process were investigated by using N2 adsorptiondesorption isotherms, thermogravimetric analysis and FfIR (Fourier Transform Infra Red). The performance and the potential use of these materials in gas separation applications depend mainly on the ability in controlling-designing the microstructurepore network in these materials.The alumina and silica sols were prepared by using aluminium isopropoxide and tetraethylorthosilicate. Sols with different H+/ AI+3 and H20 / AI+3 ratios were prepared.These peptized clear boehmite sols were used for the preparation of unsupported Ah03 membranes at 600°C. The similar ratios were varied for the preparation of clear silica sols and these sols were further dried and heat treated at 400 C.The thermogravimetric analjsis has shown that the weights of the unsupported membranes were stable at the above temperatures. The boehmite was observed to decompose to the y-Alz03 phase at about 425°C. The FfIR analysis have proved the formation of boehmite in the sols and all the organic solvent peaks disappeared upon heat treatment.The y-Alz03 membranes all displayed Type IV isothems typical of mesoporous materials. Hysteresis loops were present in all these isotherms and fast desorption took place in the 0.4-0.6 PlPo range. The BJH pore size distributions were sharp for all the samples.The desorption pore size distributions were found to become wider at an intermediate acid content membrane which also had the lowest BET surface area. The BET particle sizes of these membranes were estimated to be in the 70-100 A0 range.The throat and pore cavity sizes of monosize sphere packings for this particle size range were observed to be in close agreement with the experimentallly determined adsorptiondesorption pore sizes.The silica samples all displayed Type I isotherms with no hysteresis typical of microporous materials. The HK (Horvoath Kawazoe) pore sizes were in the 4-5 AO range. An effect of the water content of these acid-catalyzed sols on the pore size were also detected

Estimation of the surface charge distribution of solids in liquids by using atomic force microscopy

Thesis (Doctoral)--Izmir Institute of Technology, Chemical Engineering, Izmir, 2011Includes bibliographical references (leaves: 131-139)Text in English; Abstract: Turkish and Englishxxi, 152 leavesColloidal systems are widely encountered in minerals, ceramics, environment, biology, pharmaceuticals and cosmetics industries. These systems consist of micronsized particulates dispersed in a solvent. Homogeneity, dispersibility, stability of colloidal systems determines the economy and success of the final product in these applications. Control and manipulation of these properties depend on detailed analysis of the interactions among the particles. Electrophoretic potential measurements or colloidal titration methods are widely employed to characterize the charging of colloidal systems. However these methods only yield average charging information, not the charge distribution on the surface. Atomic Force Microscope (AFM) allows topographic surface analysis at nanometer level resolutions. Though it is widely used to obtain derived information AFM directly measures the forces between the tip and the surface atoms. The objective of the present work is to assess the applicability of AFM to surface charge mapping, i.e., the detection of positive or negative charged regions on metal oxide surfaces. Hence, well defined tips were prepared and allowed to interact with well defined oxide surfaces under different pH conditions. The influence of solution ion concentration and pH on the forces measured was also investigated. These measured force-distance curves were analyzed using a new solution of the one dimensional Poisson-Boltzmann equation to isolate the electrical double layer force, hence the surface charge on each measurement point. The new solution in question provides analytical expressions for all charging conditions which are amenable to such analysis.Repetitive force measurements on a predefined grid on the solid surface ultimately yield the charge distribution of the surface. Such an analysis procedure is new and advances the charge measurements on solids in solution to a new level

Trace element analysis of selected springs in the Virgin River Basin

Spring water from 23 springs in and near the Virgin River Basin (southwestern Utah, northwestern Arizona, and southeastern Nevada) was collected and analyzed for chemical concentrations. Trace elements and major ion chemistry was used to determine the potential for utilizing water chemistry to provide information on spring water source and flow pathways. Principal Component Analysis (PCA), rare earth element (REE) normalization patterns, and mineral equilibrium modeling (PHREEQE) techniques were used to analyze the data set. Four major spring water groups were displayed by the PCA, based on similarities in water chemistry. The analyses suggest that spring water chemistry is a result of interactions with the rocks through which the waters flow. The usefulness of the water chemistry to suggest actual spring source and flow pathways in the Virgin River Basin was limited due to the small number of sampling sites relative to the large areal extent of the basin

Teaching-Learning Process Self-Efficacy Beliefs Scale (TLPSEBS) for Academic Staff: A Scale Development Study

A valid and reliable measurement tool has been developed to measure the teaching-learning process self-efficacy of instructors in higher education institutions. During the scale development stage, the scale form was e-mailed to 305 instructors, who were selected through purposive sampling method, working at the faculties of health, social, science, fine arts and engineering of the randomly determined universities in 7 regions of Turkey. As a result of the explanatory factor analysis, the 8 items were excluded from the scale and the single-factor scale with remaining 40 items explained 58,309% of the total variance. The internal consistency coefficient (Cronbach’s Alpha) of the scale was found to be .98 for the whole scale. It was concluded according to these findings that the scale developed in this study is a valid and reliable measurement tool that can be used to measure the teaching-learning process self-efficacy of the instructors working in higher education institutions

THE EFFECT OF FLIPPED CLASSROOM MODEL APPLICATIONS ON HIGH SCHOOL STUDENTS’ CLASSROOM ENGAGEMENT AND CLASSROOM LIFE PERCEPTIONS IN TEACHING ENGLISH

This study investigated the effect of technology-enhanced flipped classroom model applications on high school students’ classroom engagement and classroom life perceptions in teaching English. In the study, pretest and posttest experiment-control group quasi-experimental design was used. The experimental group was taught using the flipped method and the control group was taught using the current conventional method. The study was conducted with 45 students attending 9th grade for 8 weeks. The data from classroom engagement inventory and classroom life perception scales were collected quantitatively. According to the findings, there was a significant difference in terms of classroom engagement levels. When the classroom engagement inventory sub-dimensions were examined, significant differences were found in the experimental group in terms of cognitive engagement and affective engagement sub-dimensions. However, there was not a significant difference between the two groups in terms of behavioral engagement–compliance, behavioral engagement-effortful classroom participation and disengagement sub-dimensions. On the other hand, there was a significant difference in terms of classroom life perception levels. When the classroom life perception scale sub-dimensions were examined, significant differences were found in the experimental group in terms of student feelings related to the classroom environment and student feelings related to the teacher sub-dimensions. However, there was not a significant difference between the two groups in terms of student feelings related to other students sub-dimension.&nbsp

The Effect of the Web Based Digital Story Applications on the Digital Literacy Levels of Turkish Teacher Candidates

The technological developments that have directed 21st century skills have brought new content and dimension to narrative by integrating story narration, one of the earliest verbal narrative skills of mankind, with digital technology. The purpose of this study is to determine the effect of web-based digital story preparation on the literacy self-efficacy perceptions of Turkish teacher candidates in the digital media using pre-test, posttest, experimental-control group and semi-experimental design. A total of 60 teacher candidates, including 30 experimental groups and 30 control groups attending to the Teaching Principles and Methods Course in Mersin University Education Faculty Turkish Education Department participated in the study in 2016-2017 academic year. The research data were collected by the "Digital Media-Oriented Literacy Self-efficacy Scale" developed by the researchers. As a result of the study, Digital Media-Oriented Literacy Self-efficacy levels were observed to increased in both groups. However, a statistically significant difference was found only between pre-test and post-test scores of the self-efficacy perceptions of the Turkish teacher candidates who prepared a web-based digital story in the cooperative learning approach. It is suggested regarding the results of the study that in other studies, digital storytelling approach can be utilized by taking into consideration the content of both field and cultural courses, and also that researchers can investigate the effects of digital storytelling in terms of various variables

Orta öğretim son sınıf öğrencilerinin üniversite tercihlerini ve meslek seçimini etkileyen faktörler

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Okullarda, öğrencilerin istek, ilgi, beklenti ve yeteneklerini tanıması, eğitimcilerin onlara uygun eğitim ortamlarını hazırlamaları ile mümkün olabilir. Öğrencilerin, kendilerini inceleyen, sağlanan olanakları araştıran ve sonunda doğru seçimler yapabilen bireyler olarak yetişmeleri çağdaş eğitimin önemli hedeflerindendir.Bu araştırmayla meslek seçimi, meslek seçimini etkileyen faktörler, mesleki gelişim evreleri, bireysel niteliklerin meslek seçimindeki önemi, mesleğe yönlendirme, mesleki rehberlik ve mesleki rehberlikte danışma hizmetleri üzerinde durulmuş, kuramsal çerçevesi ile birlikte açıklanmaya çalışılmıştır.Meslek seçimi, bireyin kendisine açık meslekleri, çeşitli yönleri ile değerlendirip, kendi gereksinmeleri açısından, istenilir yönleri çok, istenmeyen yönleri az olan birine yönelmeye karar vermesidir. (Kuzgun, 1982:1).Liselerde okuyan öğrenciler, seçecekleri meslekten, o mesleğin beklentilerinden ve kendi ilgi ve yeteneklerinden habersiz olarak seçim yapmaktadırlar. Bunun sonucunda üniversiteye giren gençlerin büyük bir kısmı girdikleri daldan memnun olmamaktadırlar.Türkiye'de öğrencilerin meslek seçimleri genellikle tesadüflere bağlı olarak oluşmakta ve öğrenciler üniversite sınavına girerlerken yapacakları tercihlerde öncelikle şu unsurları göz önünde bulundurup bunların doğrultusunda tercihlerini yapmaktadırlar. Bunlar ailenin beklentileri, mesleğin maddi getirisi, hayal dünyasındaki meslekler,toplumda ilgi gören meslekler şeklinde ifade edilebilir.Ancak ne var ki bu tercihler doğrultusunda üniversiteye girilse bile çoğu zaman görülen, öğrencilerin ilgi ve yetenekleri ile yukarıda belirtilen unsurlara bağlı olarak yapılan tercihlerin gerektirdiği özelliklerin birbirine uymadığıdır.İdeal bir meslek seçimi, kişinin, mutlu, başarılı ve yararlı bir yaşam sürdürmesine, toplumun insan gücü kaynaklarını en iyi bir şekilde kullanmasına olanak verecektir.Bu tanımlardan da anlaşılıyor ki meslek, kişinin yaşamının ekonomik yönünün temelini oluştururken, psikolojik yönünü de büyük ölçüde şekillendirmektedir. Bu noktada, meslek seçiminin ne kadar önemli olduğu bir kez daha ortaya çıkmaktadır. Zeka özrü bulunmayan her insanın yaşamını sürdürebilmek için yapabileceği bir iş becerisi mutlaka vardır. Ancak, kimi insan bu becerisinin farkına varıp yeteneklerini keşfedebilirken, kimi de yeteneklerini bilmeyip becerilerinin farkına varamamaktadır. Bu kimseler mesleki yaşamlarını tesadüfler sonucu başlatmaktadırlar. Bir kısmı daha sonraki zamanlarda gerçek beceri ve yeteneklerine uyan mesleklere dönerken büyük bir kısmı da aynı mesleği sürdürmeye devam etmektedirler.İnsanların mesleki seçimlerinin onların yetenek ve ilgilerine uygun olarak geliştirilmesi gerekliliği vardır. Burada amaç, öğrencilerin "her hangi alanda olursa olsun üniversite sınavını kazanmalıyım" yaklaşımı ile olur olmaz tercihlerde bulunmalarını önlemek, onların, ilgi ve yeteneklerine uygun alanlarda tercihler yapmasını ve bu tercihlerden birini kazanmasını sağlamaktır.In schools, to recognize students relation, wish, expactation, ability is possible with suitable atmosphere .The contemporary education?s important points are student?s research themselves, explore the provided possibility, and at the end make a true choices to become individual person can do those.Choosing occupation is deciding about favorable jobs, increase with different side and estimate more than intended sides, less than not intended sides by people.High school?s students are made a choice with less information about the job, which they will select in the future and their job?s expactations, their relation and their ability.At the end of this sitation, fifty-two percent of student aren?t glad in the university field.Student?s job choice in Turkey usually be formed with accidently. And students keep in mind that things which they will do before have university exam and make true choice direction at those things.With those directions, students can begin university but lots of time the student?s relations and abilities don?t match with four points.Optimum job choice, make possible to survive happily, successfully and helpfully to use human?s powers perfectly for society.We can realize by these descriptions that jobs create the main economical side of the people is life, and it give form their psychology with huge proportion. At this point appears the importance of choice. Exactly, despite the disabled people, all of the others have a job ability to go on their life. But some of the people can be sensible of their ability but unfortunatelly some of them can?t do that. Those unluck people?s job life begin with fluky.There is necessity that enables the people choose a job according to their ability and relations. Our aim at this point is preventing to choose university without ideals and on the other side, encourage them for the true choice about right field

Trace element analysis of selected springs in the Virgin River Basin

Spring water from 23 springs in and near the Virgin River Basin (southwestern Utah, northwestern Arizona, and southeastern Nevada) was collected and analyzed for chemical concentrations. Trace elements and major ion chemistry was used to determine the potential for utilizing water chemistry to provide information on spring water source and flow pathways. Principal Component Analysis (PCA), rare earth element (REE) normalization patterns, and mineral equilibrium modeling (PHREEQE) techniques were used to analyze the data set. Four major spring water groups were displayed by the PCA, based on similarities in water chemistry. The analyses suggest that spring water chemistry is a result of interactions with the rocks through which the waters flow. The usefulness of the water chemistry to suggest actual spring source and flow pathways in the Virgin River Basin was limited due to the small number of sampling sites relative to the large areal extent of the basin

Depositional Environment, Petrology, and Diagenesis of the Laverty-hoover Sandstone in Beaver, Harper, Ellis, and Woodward Counties, Oklahoma and Lipscomb County, Texas

Geolog

Öğretmen Adaylarının Portfolyoları Üzerinde Grup Olarak Yaratıcılık Temelli Materyal Geliştirmenin Etkileri

The aim of this study was to determine the effects of instructional materials development based on “Creativity Activities within a Group” on teacher candidates’ portfolios. This research was carried out with the two classes in the fall of 2007–2008 among 3rd year students enrolled in Faculty of Education’s Department of English Teacher Education. Quasi-experimental method was used and creativity-based material-development activities were applied to the experimental group. In the control group, individual materialdevelopment activities were put into practice. In both groups the teacher candidates prepared portfolios. There was a significant difference between the portfolio marks of the first and second group. The most powerful regressing item that regressed the portfolio marks of the students was the final marks at the end of the stepwise regression. Öğretim materyali geliştirme, öğretmen eğitiminde ders içeriğinin zengin bir boyutta sunulmasının öğrenilmesinde rehber olan süreçlerden birisidir. Bu çalışmanın amacı, öğretim teknolojileri ve materyal geliştirme dersinde grupla yaratıcılık temelli materyal geliş- tirmenin öğretmen adaylarının portfolyoları üzerindeki etkisini ve portfolyolarını yordayan değişkenleri tespit etmektir. Bu araştırma 2007- 2008 güz yarıyılında eğitim fakültesi İngilizce öğretmenliği 3. sınıflar üzerinde yapılmıştır. Yarı deneysel olarak yapılan bu araştırmada deney grubunda yaratıcılık temelli grup olarak materyal geliştirme etkinlikleri, kontrol grubunda ise bireysel materyal geliştirme etkinlikleri yapılmıştır. Araştırma sonucunda, portfolyo puanları arasında deney grubu lehine anlamlı farklar bulunmuştur. Öğrencilerin portfolyolarını yordayan değişkenler, öğrencilerin geçme notu, başarı son test puanları ve deneysel işlem olmuştur. Deney grubundaki öğretmen adayları grup olarak çalışmanın, beyin fırtınası yapmanın ve materyal geliştirmenin yaratıcılıklarını geliştirdiğini vurgulamışlardır