Experimental investigations on tsunami runup height on permeable beachs

Tsunamiler depremlerle tetiklenebilen zemin hareketleri, heyelanlar, kayma, göçme, çökme gibi olaylar ile oluşabilmektedir. Bu dalgalar kıyı batimetrisindeki değişimle birlikte iç kısımlara doğru ilerleyerek büyük hasarlara neden olurlar. Tsunamiler özellikle kıyı çizgisinde tırmanma bölgesinde daha etkili olduğu için tırmanma yüksekliğinin önceden tahmin edilebilmesi kıyı yapılarının boyutlandırılması açısından önemli olacaktır. Bu çalışmada tsunaminin geçirimli yüzeylerde tırmanma yüksekliği deneysel olarak incelenmiştir. 1:5 eğimde geçirimsiz yüzey pürüzsüz, düz saç levha kullanılarak oluşturulmuştur. Aynı eğimde geçirimli yüzey için dane çapı 0.35 mm ve birim hacim ağırlığı 2.63 gr/cm3 olan doğal plaj malzemesi kullanılmıştır. Tırmanma yüksekliğine etki eden parametreler dalga yüksekliği, şev eğimi, su derinliği, eğimi oluşturan malzeme özellikleri olarak belirlenmiş geçirimli yüzeyler için ampirik bir  ifade önerilmiştir.Anahtar Kelimeler: Tsunami, tırmanma yüksekliği, geçirimli kıyı, deney,eğimli kıyı, kum.Tsunamis may be generated by earthquake-triggered movement of the sea bottom, landslides and collapses. With the change of nearshore bathymetry these waves progress towards inland and causes large damage. Prediction of runup height will play an important role in dimensioning coastal structure as tsunamis are more effective in the runup area at the shoreline. In the literature research on runup height, tsunami wave is liken to solitary wave and produced by horizontal movement of a vertical plate, which is a proposed by Goring (1978). In this study, for the simulation of sudden motion of the ocean bottom, tsunami wave generation system is developed by piston attached to an horizontal plate. The piston moves vertically. Experiments were carried out in the glass-side wall wave flume of 22.5 m length, 1 m width, and 0.50 m depth at the Hydraulics Laboratory, Civil Engineering Faculty, Istanbul Technical University. The beach was formed by natural beach sand and had a slope of 1 vertical to 5 horizontal. The specific gravity of sand was 2.63 g/cm3 and the diameter of sand was 0.35 mm. In the experiments it is observed that the waves are not broken. Water surface profiles and velocity values of the waves calculated and generated are compared. Runup height of tsunami waves on permeable beach is analysed and the experimental results, for impermeable slopes are compared with the runup law and it is seen that they are in consistency. Empirical equation are proposed for permeable beach by defining parameters effecting runup height, wave height, slope, water depth, and the characteristics of the material at the slopes. Keywords: Tsunami, run-up height, permeable beach, experiment, slope beach, sand

Portable Lightboard Use in Online Higher Education

The emergency distance education period has led to new instructional experiences and unique practices in higher education. This study focuses on one such practice that included portable lightboards designed as a cost-effective solution to support instructors’ online teaching processes from their homes. Using a case study design, data were collected via using through interviews with eight students and nine instructors who used the lightboard for the first time in order to to explore their perceptions and lived experiences. The findings obtained in this study showed that the instructors could benefit from the writing/drawing feature supported by the dynamic drawing principle of multimedia learning from their homes. Student engagement was enhanced due to offering a sustainable learning environment resembling face-to-face courses with unique limitations. The results offer key aspects of portable lightboards with great potential for future online or blended learning environments

EXPERIMENTAL INVESTIGATION ON REFLECTION AND ENERGY LOSS OF TSUNAMI OVER THE PERMEABLE BEACH

The aim of this study is to investigate the reflection coefficient and the energy loss of tsunami as experimentally. The beach was built as a natural sandy one with grain diameter of 0.35 mm and the specific gravity of 2.63. The slopes of the beach were selected as 1/1.5, 1/5 and 1/8, respectively. As a result of experimental investigations, beach slope, tsunami run-up height, incident and reflecting wave heights, the characteristics of the beach material, and specific gravity of the water were determined as the parameters having the effect on both the reflection coefficient of tsunami and wave energy loss. These parameters are obtained as a dimensionless group via Buckingham’s Pi theorem. In addition, considering regression analysis, the relationship giving as dimensionless wave energy loss was proposed. The additional experiments were performed for different slopes that are 1/2.5, 1/3.5 and 1/6.5, respectively in order to verify the proposed equations derived from the study. Furthermore, the total energy values of the incident and the reflecting waves were calculated from the equation given in Coastal Engineering Manuel (CEM). These results were compared with the results of the proposed equations, and it was shown that there was a good agreement between the results

Karma öğrenme ortamı kullanımı üzerine tasarım tabanlı bir araştırma.

The purpose of this study is to examine and describe student and instructor experiences and perceptions of course design, and identify the critical issues regarding the use of a blended learning environment. A design based research (DBR) framework with qualitative approaches was carried out by collecting data from an undergraduate course offered to sophomores. The primary approach was phenomenology using the lens of heuristic inquiry. Interviews, questionnaires, documents, observation notes, instructor diary, and weekly reflection reports were the main data sources. Data were collected in three periods: preliminary study, pilot study, and actual implementation. The results of instructor experiences revealed that instructor considerations for the analysis period centered on needs and context. The design and development considerations centered v on pedagogical approach, course materials and documents, course organization, interaction, and instructor-student roles. The enablers (benefits and opportunities) of the implementation period included arousing student interest and participation potentially more, having flexibility, saving time, tracking student progress more easily, and increased interaction, collaboration, and communication opportunities. The barriers (challenges and limitations) were increased workload, difficulties related to the course and time management, overlaps, and creating harmony among F2F and online environments. The students mentioned interaction and communication opportunities, increased motivation, opportunity to voice opinions, and reinforcement of learning as enablers of the blended learning environment. The barriers were increased workload, cultural and technical barriers and dependability of environments. The critical issues were found to be context, pedagogical framework, instructor competency, and technical issues. It can be concluded that use of blended learning environments can be regarded as a paramount initiative for the higher education institutions by maximizing the enablers of both environments but also has its unique barriers to consider. The results also implied that it is the decisions on the instructional design approaches for creating balance in the course activities that is critical to blended learning environment designs.Ph.D. - Doctoral Progra

Least Squares Support Vector Mechanics to Predict the Stability Number of Rubble-Mound Breakwaters

In coastal engineering, empirical formulas grounded on experimental works regarding the stability of breakwaters have been developed. In recent years, soft computing tools such as artificial neural networks and fuzzy models have started to be employed to diminish the time and cost spent in these mentioned experimental works. To predict the stability number of rubble-mound breakwaters, the least squares version of support vector machines (LSSVM) method is used because it can be assessed as an alternative one to diverse soft computing techniques. The LSSVM models have been operated through the selected seven parameters, which are determined by Mallows’ Cp approach, that are, namely, breakwater permeability, damage level, wave number, slope angle, water depth, significant wave heights in front of the structure, and peak wave period. The performances of the LSSVM models have shown superior accuracy (correlation coefficients (CC) of 0.997) than that of artificial neural networks (ANN), fuzzy logic (FL), and genetic programming (GP), that are all implemented in the related literature. As a result, it is thought that this study will provide a practical way for readers to estimate the stability number of rubble-mound breakwaters with more accuracy

Design of a blended learning environment: Considerations and implementation issues

This study identified critical issues in the design of a blended learning environment by examining basic design considerations and implementation issues. Following a design-based research approach with the phenomenological tradition of qualitative research, the study investigated instructor experiences relating to the design, development, and implementation processes of a blended course. The results reveal that the design considerations centred on the pedagogical approach, course organization, materials preparation, interactions, and the instructor's and students' roles. The affordances of the implementation included the arousal of the students' interest and participation, flexibility, time conservation, the ability to track student progress, and the improvement of interaction, collaboration, and communication opportunities. The challenges were increased workload, course and time management, overlaps, and the creation of harmony between the face-to-face and online environments. The overall results show that the critical issues involved context, the pedagogical framework, instructor competency, and technical issues in the blended course design

Key instructional design issues in a cellular phone-based mobile learning project

Adding flexibility to the learning process, mobile learning offers great opportunities for education, especially for teenagers, who show great attentiveness to mobile technologies. Thus, the need to focus on design aspects of such learning is growing. This study aims to reveal critical issues in designing mobile learning based on a program for 11th graders and to unfold students' perceptions about reasons for participation, satisfaction, implementation processes, and specific content representation types. Reflections on insights gleaned from the instructional design process of the project and students' perceptions are presented with related recommendations

Numerical and Experimental Analysis of Rapid Delta Formation, Turkish coast

The morphology of river mouths can be completely changed by dramatic flow changes caused by climate changes in catchment basins. Agricultural activities that overexploit water produce changes in sediment discharge that are reflected in sedimentation rates in dams. The basic aim of this study is to assess the causes and effects of rapid delta. formation in Gomec (an important tourism centre on the Aegean Sea coast of Turkey), as a result of river catchment changes between 1998 and 2001. The rapidly developing delta covers an area of approximately 2 km length and 100 m width and was studied using numerical simulation and field studies. Bathymetric measurement, flow velocity and oceanographic parameters were measured. Bottom sediment samples were taken from the river and adjacent sea and sources were determined by mineral analysis. River flows and wave properties (determined from hindcast wind data) were used in the numerical model studies. The development of the delta was predicted for different scenarios. It is concluded that unless remedial action is taken, the delta will continue to develop rapidly and will produce both morphological and ecological impacts