Quantification of the modification of cratonic lithospheric mantle by major tectono-magmatic events:A petrological and geochemical study of mantle xenoliths from the Tanzania Craton

Davies, G.R. [Promotor]Koornneef, J.M. [Copromotor

Feedforward backpropagation, genetic algorithm approaches for predicting reference evapotranspiration

Water scarcity is a global concern, as the demand for water is increasing tremendously and poor management of water resources will accelerates dramatically the depletion of available water. The precise prediction of evapotranspiration (ET), that consumes almost 100% of the supplied irrigation water, is one of the goals that should be adopted in order to avoid more squandering of water especially in arid and semiarid regions. The capabilities of feedforward backpropagation neural networks (FFBP) in predicting reference evapotranspiration (ET0) are evaluated in this paper in comparison with the empirical FAO Penman-Monteith (P-M) equation, later a model of FFBP+Genetic Algorithm (GA) is implemented for the same evaluation purpose. The study location is the main station in Iraq, namely Baghdad Station. Records of weather variables from the related meteorological station, including monthly mean records of maximum air temperature (Tmax), minimum air temperature (Tmin), sunshine hours (Rn), relative humidity (Rh) and wind speed (U2), from the related meteorological station are used in the prediction of ET0 values. The performance of both simulation models were evaluated using statistical coefficients such as the root of mean squared error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The results of both models are promising, however the hybrid model shows higher efficiency in predicting ET0 and could be recommended for modeling of ET0 in arid and semiarid regions

Pengembangan Instrumen Penilaian Psikomotor pada Pembelajaran IPA Kelas V SD

Penelitian ini merupakan penelitian pengembangan. Tahap penelitian ini dibatasi sampai pada tahap perbaikan desain. Permasalahan dalam penelitian ini meliputi (1) bagaimanakah kondisi objektif instrumen penilaian psikomotor pada pembelajaran IPA di kelas V SDN 32 Kota Selatan? (2)  bagaimanakah  instrumen penilaian psikomotor pada pembelajaran IPA yang akan dikembangkan di kelas V SDN 32 Kota Selatan? dan (3) bagaimanakah kelayakan insrtuman penilaian psikomotor yang telah dikembangkan  di SDN 32 Kota Selatan?. Objek dalam penelitian ini adalah Instrumen Penilaian Psikomotor pada pembelajaran IPA kelas V di SDN 32 Kota Selatan. Tehnik pengumpulan data yang peneliti gunakan yaitu tehnik wawancara, observasi, dan dokumentasi. Produk yang dihasilkan oleh peneliti dalam penelitian pengembangan ini berupa produk instrumen penilaian psikomotor pada pembelajaran IPA kelas V di SDN 32 Kota Selatan, yang didalamnya memuat sampul buku, kata pengantar, daftar isi, petunjuk Penggunaan, pembatas KD, lembar kerja peserta didik, instrumen penilaian, rubrik penilaian, portofolio dan daftar pustaka. Hasil penelitian pengembangan tersebut divalidasi oleh ahli materi dan memperoleh skor hasil validasi 85,71 dan untuk ahli media memperoleh skor 96,47. Hasil rekapitulasi skor validasi dari 2 validator memperoleh skor keseluruhan 91,09. Berdasarkan hasil penelitian dapat disimpulkan bahwa instrumen penilaian psikomotor pada pembelajaran IPA yang dikembangkan sangat layak digunakan serta dapat dilanjutkan ketahap selanjutnya. &nbsp

Evaluation Techniques for the Corrosion Resistance of Self-Healing Coatings

Self-healing coatings, materials that autonomically repair damage, are a method of extending the life of corrosion prevention coatings. The different types of self-healing coatings are briefly outlined. A review of the evaluation methods of the performance of self-healing coatings using electrochemical, surface and microscopy techniques are provided. Both global and local evaluation techniques are reviewed with emphasis on the most used electrochemical techniques as well as suggestions for alternative electrochemical techniques for self-healing coating evaluation

New electrospun polystyrene/Al2O3 nanocomposite superhydrophobic coatings; Synthesis, characterization, and application

The effect of electrospinning operational parameters on the morphology, surface roughness, and wettability of different compositions of electrospun polystyrene (PS)-aluminum oxide (Al2O3) nanocomposite coatings was investigated using different techniques. For example, a scanning electron microscope (SEM) coupled with an energy dispersive X-ray (EDX) unit, a Fourier transform infrared (FTIR) spectrometer, an atomic force microscope (AFM), and water contact angle (WCA), and contact angle hysteresis (CAH) measurements using the sessile droplet method, were used. The latter used 4 μL of distilled water at room temperature. PS/Al2O3 nanocomposite coatings exhibited different morphologies, such as beaded fibers and microfibers, depending on the concentration ratio between the PS and Al2O3 nanoparticles and the operational parameters of the electrospinning process. The optimum conditions to produce a nanocomposite coating with the highest roughness and superhydrophobic properties (155° ± 1.9° for WCA and 3° ± 4.2° for CAH) are 2.5 and 0.25 wt % of PS and Al2O3, respectively, 25 kV for the applied potential and 1.5 mL·h-1 for the solution flow rate at 35 °C. The corrosion resistance of the as-prepared coatings was investigated using the electrochemical impedance spectroscopy (EIS) technique. The results have revealed that the highly porous superhydrophobic nanocomposite coatings (SHCs) possess a superior corrosion resistance that is higher than the uncoated Al alloy by three orders of magnitude. © 2018 by the authors.Acknowledgments: This publication was supported by Qatar University Internal Grant No. GCC-2017-012. The findings achieved herein are solely the responsibility of the authors. Thanks are also due to Anton Popelka for assistance with the AFM analysis.Scopu