331 research outputs found
An investigation on renewable energy education at the university level in Turkey
No full textIn the present study, to discover how teaching of renewable energy sources in Turkey is carried out at the
university level, a questionnaire was developed and applied at different universities in Turkey. The
analyses conducted on the data obtained from the questionnaire revealed that education about
geothermal, solar and wind energy is given at master’s level, other renewable energy sources are taught
at the undergraduate level within the curriculum of some engineering courses. The teaching performed
about renewable energy sources is in Turkish and at encyclopedic level. As preparing and obtaining the
required materials are costly, some problems are encountered in the teaching of renewable sources. In
Turkish universities, no degree about renewable energy sources is granted. Hence, the country must
make use of the people having engineering degree to capitalize on its renewable energy sources. As there
is no program specializing on providing training about the renewable energy sources, it seems to be
difficult to find experts about this issue. The current state of renewable energy sources education seems
to be inadequate and it should be expanded and strengthened
The effect of personality traits on organisational stress: A study about nurses
No full textİnsanların benzer olaylara birbirinden farklı tepkiler sergilediği; benzer durumlar hakkında birbirlerinden farklı düşündükleri, aynı amaca ulaşabilmek için farklı yolları tercih ettikleri görülebilmektedir. Stres kaynaklarından etkilenme stres düzeylerinin bireyden bireye farklılık göstermesi, aynı iş ortamında çalışan kişilerin stres yaratan olaylar karşısında aynı tepkiyi vermesi beklenemez. Bireyin stresten etkilenme düzeyi ve stresi toleransı kişilik özelliklerine göre farklılıklar gösterir. Kısacası stres oluşumunda kişilik özelliklerinden kaynaklanan farklılıklar önemli bir olgudur. Bu çalışma, Antalya ili merkez Atatürk Devlet Hastanesinde çalışan hemşirelerin kişilik özellikleri ve örgütsel stres üzerine etkileri arasındaki ilişkiyi ortaya koyma amacını taşımaktadır. Çalışmanın birinci bölümünde kişilik özellikleri, ikinci bölümünde örgütsel stres ve üçüncü bölümünde ise konuya ilişkin olarak yapılan anket çalışmasının sonuçları değerlendirilmiştir. Bu anket çalışması SPSS yardımıyla analiz edilmiştir. Araştırmanın sonucunda; Hemşirelerin kişilik özellikleri ile örgütsel stres arasında anlamlı ilişkiler bulgulamıştır.It can be seen that human beings react differently to the same events, have different views about the same phenomena, and use different ways in order to achieve the same purpose. As a result of the different influences of stress sources and having different levels of stress individuals to individuals, the employees who have the same job are not able to react to the same events. The level of being affected by stress and the toleration of stress show differences because of depending on personality traits. In brief, the differences which are based on personality traits are important about the formation of stress. The study aim to shed light on the relationship between the personality traits of the nurses, who work in Atatürk State Hospital in Antalya, and organisational stress. In the first part of the study personality traits, secondly, organisational stress and lastly the results of questionnaire about the topic are evaluated. The questionnaire was analysed by utilising SPSS. As a conclusion of the study, it can be said that there are significant relations between personality traits of the nurses and organisational stress
Seismic Modeling and Imaging for Detection of Clandestine Tunnels
No full textCovert subterranean tunnels have especially been used for drug smuggling and illegal trading across country boarders such as the United States – Mexico, Egypt – Israel and so on over the years. Conventional border security measures and intel activities of border security agencies remain insufficient in stopping these illegal underground passageways. During the 2016 U.S. presidential election, arguments were particularly focused on constructing a wall that contains sensors to locate possible existing and future clandestine tunnels between the U.S. and Mexico. The reliability of a specific scientific method that can detect tunnel locations accurately has not been established yet. Among many proposed methods, seismic method is a promising technique for imaging those tunnels, despite its many potential drawbacks, such as low signal-to-noise ratio (S/N), scattering, absorption, and heterogeneity of complex subsurface structures. Instead, by assigning proper parameters into numerical modeling and projecting, the modeled results derived from these forward numerical model examples may allow us to investigate the seismic detection capability under optimal conditions and various data acquisition geometries. The experience acquired from the numerical modeling and imaging may lead us to locate the clandestine tunnels under realistic conditions. In our modeling, we use the elastic full-wave finite-element method to simulate seismic wave interaction with subsurface tunnels. We test different frequencies and observational geometries including surface and borehole sources and receivers. We then used the modeled seismic data to implement the Kirchhoff migration. We have investigated various types of soils and boundary conditions. The modeling and imaging can help us define the optimal seismic data acquisition scheme for detecting subsurface voids and tunnels.Earth and Atmospheric Sciences, Department o
Designing preservation. Integrating the architectural project to UNESCO tools to tackle territorial fragility: the Tivoli case as a pilot experience
No full textThe research investigates the potential contribution of a design-based approach to the current institutional UNESCO safeguard tools concerning the relation core/territory, challenging the conservative role of buffer zones that lead to stalemate situations in terms of territorial development, especially in the Italian context. Through the analysis of case studies, a methodological approach is developed that focuses on the one hand on the use of design tools for the assessment of heritage-related territories (cognitive framework), and on the other hand on the use of design actions in the management strategies for valorisation (interpretation framework). These tools are tested on the relevant experimental case of Tivoli, seat of two major World Heritage sites, as a pilot experience of integration of design tools in safeguard and management strategies for the solution of territorial fragility in complex heritage-related contexts
Analysis of Failed SSH Attempts for Intrusion Detection
No full textSSH brute force attacks remain among the most common attack types in computer systems. Recent threat analysis reports consistently highlight their prevalence as a top web security vulnerability. Various passive and active methodologies have been developed to deal with this problem, each with its unique set of advantages and disadvantages. Amongst all, analysis of monitoring logs is important to understand the root cause of the problem and implementing necessary countermeasures. Hence, this thesis focus on implementing automated intrusion detection solutions by analyzing historical failed SSH attempts. The data is captured between March 2022 and June 2022 from a server located at University of Nevada, Reno (UNR) campus. We first present thorough analysis of the dataset understand common patterns in the dataset such as origin of IP addresses, usernames, and time of SSH attempts. We identified various types of attack patterns, including slow, steady, and stealthy ones. Since the logs contain both benign and malicious attempts, we utilized external databases (e.g., IPWHOIS and ABUSEIPDB) to classify them as malicious or not, which served as a training data for machine learning models. We developed several machine learning models to categorize SSH attempts as malicious or benign. The models relied on several features including username, time difference of the attacks, the number of previous attempts, and similarity of IP addresses. We trained Random Forest, Decision Tree, XGBoost, SVM, and Logistic Regression models to evaluate their performance. The Decision Tree model exhibited the best performance, achieving 100% precision and a recall rate of 97.9%. In comparison, the best performed rule-based formulation failed to identify 1.5% malicious IPs whereas the Decision Tree model only missed 0.01%. We also validated the results against the public datasets. We noticed that the proposed model detected five malicious IP addresses before they appear in public databases such as ABUSEIPDB, which is a promising result for the proposed model
Sodyum iyon pil uygulamaları için fosfor/karbon kompozitlerinin sentezi ve elektrokimyasal karakterizasyonu
No full text06.03.2018 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.Rüzgar ve güneş gibi yenilenebilir enerji kaynakları, fosil yakıtların tükenmesi ve çevresel kaygılar nedeniyle önemleri gün geçtikçe artmaktadır. Mevcut hali ile yer kabuğunda az bulunan lityum kaynaklarının gün geçtikçe azalması ve maliyetlerinin artması bir takım yüksek ölçekli enerji depolama uygun aday olamamasını sağlamaktadır. Ancak, sodyumun yer kabuğunda bol bulunması ve ve ucuz olmasının yanı sıra lityum ile benzer kimyasal özellikler sergilemesi enerji depolama hususunda önemini gün geçtik artmaktadır. Bu nedenle, son yıllarda sodyum iyon pillerin üzerine gidilerek daha fazla araştırma yapılmaktadır. Bu tez çalışmasında, sodyum iyon pillerde anot elektrodu olarak umut vaat eden kırmızı fosfor seçilmiştir. Ancak söz konusu anot elektrotlarının çevrim performansları henüz tatmin edici seviyede değildir. Deneysel çalışmalar yoluyla partikül boyutları küçültülmüş ve yüzeylerinde iletken karbon tabaka oluşturularak, P/karbon nanotüp ve P/grafen nanokompozitleri sentezlenmiştir. Bunun yanı sıra mekanik alaşımlama yöntemi ile farklı sürelerde fosforun tane boyutları önemli ölçüde küçültülmüştür. Ayrıca, bu elektrot malzemelerinin morfolojisinin ve sodyum depolama mekanizmasının etkileri, alan emisyon taramalı elektron mikroskopisi ve X-ışını toz difraksiyonu de dahil olmak üzere çeşitli karakterizasyon teknikleri kullanılarak araştırılmıştır. P/KNT kompozitleri, sadece mikro boyutlu kırmızı fosforun KNT'lerle bilyalı değirmende öğütülerek karıştırılmasıyla hazırlanmıştır. Bu şekilde hazırlanan P/KNT kompoziti, beklenmedik bir şekilde, oldukça tersinir sodyum depolamaya sahip olduğu gözlenmiştir. Kötü elektron iletkenliğinin ve kırmızı P'nin muazzam hacim genişlemesinin, kırmızı P'nin geri dönüşümünü ve döngü kararlılığını engelleyen başlıca engeller olduğu sonucuna varılmıştır. Bu problemleri engellemek için Bölüm 2'de bazı yöntemlerden bahsedilmiştir. Bunlardan biri bilyali öğütme yöntemiyle (P/Grafen) kompozitleri hazırlamak için P, grafen nanoyaprakları ile kombine edilmiştir. Böylece P'nin parçacık boyutu azaltılıp grafen nano yaprakları arasına eklenmiştir. Buna ek olarak P/Grafen kompozitinde, fosforokarbon bağları oluşturulmuştur. Bu sonuçlar ışığında P/C kompoziti 100 mA g-1 akım yoğunluğunda 1550 mA g-1'lık tersinir kapasite değeri sağlamış ve 10 çevrim sonunda kapasitesinin %82,5'ini koruyarak mükemmel çevrim kararlılığı göstermiştir.Renewable energy sources, such as wind and sun, have attracted ever-growing attention due to exhaustion of fossil fuels and environmental concerns. In some applications, lithium ion batteries are not suitable candidates because of the low abundance of lithium resources and their high cost. In comparison, sodium is abundant and cheap, and also has similar physical and chemical properties to lithium. Thus, more and more investigations on sodium ion batteries have been emerging in recent years. In this thesis work, promising red phosphorus was chosen as the objects of study, although their cycling performance is not yet satisfactory. Through reducing the particle size and forming composites with conductive carbon, P/carbonnanotube (CNT) and P/graphene nanoplate composites were synthesized. Therefore P samples amorphization different times. Moreover, the influences of the morphology and the sodium storage mechanism of these electrode materials were investigated through various characterization techniques, including field emission scanning electron microscopy, X-ray powder diffraction. P/CNT composite was prepared just by simply mixing microsized red phosphorus with CNTs by ball milling. The thus-prepared P/CNT composite unexpectedly exhibited highly reversible sodium storage. It is concluded that the poor electronic conductivity and huge volume expansion of red P is the main obstacles which inhibit the reversibility and cycling stability of red P. Consequently, we propose some strategies to dissolve these problems in chapter 2. One of them is combination with graphene nanoplate to prepare (P/GnP) composite by the ball-milling method. The particle size was reduced and incorporated in graphene nanoplates, in addition, the phosphoruscarbon bonds were formed in the P/GnPs composite. This chemical bond improves the electrical connectivity between the P particles and the graphene nanoplates, consequently stabilizing the structure of the composite to achieve high cycling performance and rate capability. As a result, the red phosphorus and graphene nanoplate composite delivered high reversible capacity of 1146 mAh g-1 at the current density of 100 mA g-1 and excellent cycling stability for 200 cycles with 92.5% capacity retention
On the relations between subgroups of a group and submodules of modules over group rings
No full textLet R be a commutative ring and G a finite group. In [1], using a structure on an R module M to make it an RG module, we find some relations between RG submodules and a subgroups. We also prove that for each normal subgroup H of G with an invertible IHI in R, there is a direct summand RG submodule of M
Gillnet selectivity for non target fish species caught by red mullet gillnets north Aegean Sea
No full textThe aim of this study is to determine the effects of red mullet gillnets that commonly used in Turkish waters on sustainability of non target fish species. For these purpose, surveys were realized with 18 - 20 - 22 mm nominal bar length red mullet gillnets between December 2008 and May 2010 along the north Aegean Sea coasts (5-30 m). SELECT method was used with five different model (Normal location, normal scale, log-normal, gamma and bi-modal) for evaluating selectivity parameters of non target fish species. Selectivity models were determined as bi-modal for Serranus scriba and Symphodus tinca, log normal for Scorpaena porcus and Spicara maena and gamma for Pagellus acarne. Optimum catch lengths and spread values and selectivity curves were given for 5 species. Results showed that use of a larger mesh size over the 22 mm mesh is important for ensuring stock sustainability of the non target fish species.Tubitak [106Y021]This study supported by Tubitak 106Y021 numbered Project. Results of this study contains a part of Msc thesis of Engin Kocabas. Thanks are extended to Cahit Ceviz and Osman Odabasi
Modeling of plastic deformation due to slip-its implications in characterizing fatigue crack growth thresholds and non-Schmid behavior in transforming alloys
No full textThis study will be divided into two main pillars in interrogating the microstructural barriers prevalent at the nanoscale: (i) the effect of twin and grain boundaries along with their contribution on the irreversibility of the crack-tip emitted slip under cyclic fatigue loading, (ii) the atomistic scale lattice resistance against glide motion of dislocations in a perspective of laying out the dislocation core-crystal structure and applied loading interplay in particular embracing the plastic behavior in ordered shape memory alloys. The primary goal of the current work is to provide physical insight for the implications of the slip-mediated plasticity in fatigue crack growth and non-Schmid behavior on both experimental and theoretical grounds.
In first part of the current study, the near threshold fatigue crack growth behavior of nanocrystalline Ni-2.89% wt. Co (Ni-Co) alloy with nanotwinned microstructure will be characterized in particular based on the contribution of microstructural variables such as the on-going crack-tip emitted dislocation and twin/grain boundary (i.e. of , and types) interactions, the pre-existing dislocation density and the characteristic dimensions of grain size, twin thickness and spacing. In order to accomplish this task, we architectured the microstructure of nanocrystalline Ni-Co alloy by conducting annealing treatments at various temperatures and promoted grain-twin coarsening as well as varying the pre-existing slip density. Furthermore, we conducted experiments on these engineered microstructures under uniaxial tension and cyclic fatigue loading employing Digital Image Correlation technique at different length scales. The monotonic tension experiments enables to characterize the contribution of microstructural variables on the mechanical response of Ni-Co alloy, such as ductility and strength. On the other hand, the cyclic fatigue crack growth experiments help identify the variation of crack growth behavior and threshold levels of Ni-Co alloy along with the architectured microstructures. The experimental measurements show that nanotwins hierarchically embedded in the microstructure of Ni-Co alloy promotes ductility and fatigue threshold in a profound fashion with decreasing characteristic dimensions.
Meanwhile, the primary focus is on nanocrystalline Ni-Co alloy, the current work has been put forward to establish a physical model informed by the multi-scale microstructural parameters which is capable of predicting the fatigue threshold levels of metallic materials devoid of empiricism. To that end, we simulated the interaction of crack-tip emitted slip and the grain/twin boundaries within the framework of Molecular Dynamics and characterized the on-going dislocation reactions as well as the crystalline resistance at the boundary against the glide of dislocations participating in these reactions. Subsequently, the effective threshold stress intensity factor range metric is predicted on theoretical grounds by incorporating physical parameters such as the friction stresses both inside the pristine crystal and at the grain/twin boundaries along with the glide geometry associated with the prevailing dislocation reactions into the continuum scale dislocation motion equations. The modelling efforts for cyclic glide motion of crack-tip emitted dislocations as a function of applied stress factor range , , provided a quantitative basis to determine the microstructure-sensitive crack threshold levels on theoretical grounds. The results indicate that coherent twin boundaries ( type ) impart superior fatigue properties to Ni-Co alloy compared to the less-coincident grain boundaries of and types. As a distinguishing finding of the present study, the increasing frequency of the grain and twin boundaries-linked with the grain size and twin spacing & thickness- are determined to promote the fatigue threshold levels in Ni-Co alloy.
In the second part of the study, the mechanisms governing the slip-mediated plasticity of the ordered shape memory alloys, particularly Fe3Al and NiTi, are focused on both experimental grounds (via Digital Image Correlation technique) and employing theoretical atomistic scale dislocation core simulations. The non-Schmid character of the plastic response profoundly governs on the functional performance of this class of alloys imparting tension-compression asymmetries and anisotropic glide resistance as a function of crystal orientation. To accomplish this task, the dislocation core structures are calculated employing Molecular Statics-Dynamics simulations and subsequently the interaction mechanisms of the non-planar dislocation core structure with applied stress tensor components are identified considering the corresponding crystal symmetries involved. The dislocation core shape that is governed by the atomistic scale disregistry distributions under applied loading is demonstrated to play a decisive role on the anisotropic glide resistance which results in deviations from the Schmid law. The theoretical predictions for the anisotropic glide resistance are demonstrated to be in well agreement with the high magnification experiments conducted on single crystals of these alloys. The current methodology followed enables us to build a comprehensive understanding for the non-Schmid glide behavior of dislocations in austenitic phase of Fe3Al and NiTi shape memory alloys considering the effects of both glide and non-glide stress components. Furthermore, generalized yield criteria for these materials are established extending atomistic scale core mechanics to the macro-scale crystal plasticity.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-12-01The student, Sertan Alkan, accepted the attached license on 2017-12-05 at 13:43.The student, Sertan Alkan, submitted this Dissertation for approval on 2017-12-05 at 14:02.This Dissertation was approved for publication on 2017-12-06 at 10:46.DSpace SAF Submission Ingestion Package generated from Vireo submission #11864 on 2018-03-13 at 09:56:57Made available in DSpace on 2018-03-13T15:25:27Z (GMT). No. of bitstreams: 3
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Prospective teachers' views and experiences with e-portfolios
No full textThe use of electronic portfolios (e-portfolios) is a burgeoning area ofresearch, with many teacher education programs utilising as botha product of and a process of reflective practice. This case studyaimed to explore prospective primary teachers’ (students) percep-tions, perspectives and experiences of the use of e-portfolios, focus-ing on the affordances and limitations of using e-portfolios in InitialTeacher Education (ITE). Eleven second-year undergraduate stu-dents from secondary and primary ITE programs were interviewed.A reflexive thematic analysis was conducted on the transcripts, inwhich the module tutors’ experiences were also incorporated.Findings suggest that e-portfolios can be valuable agentic andreflective pedagogical tools that can scaffold learning, althoughwith a number of important caveats for future implementations.This paper speaks to the paucity of research that extends the viewof e-portfolios as simply repositories for content.ARTICLE HISTORYReceived 11 December 2023Accepted 27 August 2024KEYWORDSE-portfolio; reflection; initialteacher education; ScotlandIntroductionThe definition and application of reflection, especially in initial teacher education, is bothcontested and complex. Typically, Dewey’s (1933) book called How We Think and Schön’s(1983) work on becoming a reflective practitioner are regarded as the foundational textsin this area. Dewey defined reflection as ‘an operation in which facts on one side andmeaning on the other are elicited through constant interaction with each other’ (1933,p. 165). Schön (1983) further developed this idea, emphasising the importance of thedevelopment of ‘feeling for practice’ within specific contexts. He highlighted the signifi-cance of uncertainties in his discussion on reflection, noting that ‘it is our capacity to see-as and do-as that allows us to have a feel for problems that do not fit existing rules’ (1983,p.140). Similarly, LaBoskey (1993), who argued that reflection should clearly be an objec-tive for all teachers, stated that ‘reflection begins when an individual is perplexed oruncertain about an idea or situation and ends with a judgement’ (p.10). The process bywhich these judgements are formed and can be documented was further examined byCONTACT Sinem Hizli Alkan [email protected] School of Education, Faculty of Arts, Humanities,Education and Social Sciences, Anglia Ruskin University, Bishop Hall Lane, Chelmsford CM1 1SQ, UKREFLECTIVE PRACTICEhttps://doi.org/10.1080/14623943.2024.2398800© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) orwith their consent.</p
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