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"Estuaries, which are rich in nutrient, act as a habitat to some aquatic lives, including mangroves. Human-induced activities such as dredging and shoreline development influence estuarine dynamics which includes mixing process. This will further affect estuarine salinity and adversely affect the aquatic life. A laboratory investigation was conducted in a flume to observe the mixing in a salt-wedge estuary. Three conditions were studied, i.e. mixing in ordinary estuary, mixing in an estuary with a presence of smaller deep channel and mixing in an estuary with a presence of resisting structures along the channel banks. Freshwater was run from one end of the channel, overflowing a weir at the other end, while salt water was introduced at the base of the weir and intruded upstream as gravity current. Mixing in open channel occurs in longitudinal, vertical and transverse directions. The spatial and temporal salt-water intrusions were studied where the mixing patterns were visualized using red dye tracer. To have better understanding on the mixing process, salinity patterns are studied through the plotted isohalines. The spatial and temporal salinity profiles in the flume are also studied through plotted graphs. The results show that salinity differences occurred due to the interfacial mixing between saline and freshwater"

"This book about more than just distances from electron density studies, modeling and analysis of hydrogen atoms, charge density methods in hydrogen bond studies. some main group chemical perceptions in the light of experimental charge density investigations. electronic structure and chemical properties of lithium organics seen through the glasses of charge density. bond orders in metal–metal interactions through electron density analysis, and on the nature of β-agostic interactions : a comparison between the molecular orbital and charge density picture."

"ABSTRACTThe combination of the coupled mode and normal mode theories has been used to formulaic the theoretical performance represented by the coupling length and crosstalk parameters of the X-cut APE-LN SDC fabricated using the benzoic acid as the proton source, where in this case the matrix effective refractive index (MERI) method is applied for solving the symmetric and antisymmetric propagation constants of the normal modes propagating in this device. The corresponding near field method has been used to experimentally determine its crosstalk. The actual performance of this device is characterized by comparing the theoretically calculated with the experimentally determined crosstalk parameters. A software computer program has been developed in order to numerically characterize the entire characteristic and performance of the SDC under study. For the SDC under study, the best crosstalk obtained at the operating wavelength lamda =1.3 micrometer is ~0.21 dB for the interaction length L = 6 mm and the gap separation g = 5 mm. Its coupling length is ~ 1.33 mm. The propagation constant of the corresponding individual single-mode X-cut APE-LN channel waveguide making up this SDC is beta = 10.37901 micrometer, and thereby its effective refractive index is N cπ= 2.14743330. It has been shown that the fabricated SDC is very lossy. It has been deduced that its bad performance predominantly caused by the side diffusion effect, corresponding to the fabrication problem, where in this case the substrate sample has been not coated first with the buffer layer when the deposition of substrate sample with the aluminum mask was to be performed in the fabrication stages. Moreover, in this case only the simple annealing has been performed. The successive annealing process in order to reduce the coupling loss has been not applied yet. Under the assumption that the fabrication tolerances are such that the practical devices with coupling loss below 0.25 dB are feasible, the fabricated SDC under study is a 3 dB coupler. "

"Balok pracetak berongga atau hollow core beam (HCB) merupakan pengembangan atau inovasi dari Hollow-Core Slab (HCS). Balok pracetak berongga bukanlah produk baru dalam dunia konstruksi, karena sudah digunakan untuk girder pada jembatan dan balok pada bangunan-bangunan tinggi. Rongga pada balok ditujukan untuk mengurangi berat balok untuk kemudahan mobilisasi pelaksanaan konstruksi di lapangan, namun pada akhirnya rongga tersebut dicor setelah ditempatkan, hanya karena pertimbangan kemudahan pelaksanaan. Perlu dilakukan penelitian untuk mencari metode pelaksanaan yang mudah agar rongga tersebut tetap dipertahankan sehingga menghemat volume beton yang digunakan di proyek konstruksi.Studi eksperimental untuk mencari metode pelaksanaan yang mudah serta mempelajari pengaruh rongga pada balok pracetak terhadap kekuatan lentur telah dilakukan dengan enam (6) benda uji berukuran 200 x 400 x 3850 mm, serta menggunakan dua mutu beton yang berbeda, yaitu K-300 dan K-400. Four point loading test dipilih untuk melihat perilaku balok. Tiga (3) spesimen balok beton bertulang K-400 solid dengan ukuran yang sama juga dites sebagai balok pembanding. Hasil pengujian dianalisa berdasarkan grafik hubungan antara beban – lendutan, grafik hubungan antara momen - putaran sudut di tengah bentang, serta pola retak yang terjadi pada masing-masing spesimen.Hasil pengujian menunjukkan balok berongga K-400 memiliki kekuatan lentur 0.98 kali kekuatan lentur balok solid dengan mutu beton yang sama. Balok berongga K-300, memiliki kekuatan lentur 0.965 kali kekuatan lentur balok berongga dengan mutu beton K-400. Penelitian ini juga memberikan gambaran proses pembuatan balok berongga cast in site (cor setempat) yang dapat diterapkan dilapangan.

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Precast Hollow-Core Beam (HCB) is an innovation of Hollow-Core Slab, and not a new product in the construction. It has been used as girders of bridge and beams in high-rise buildings. The hollow is intended to reduce beam weight for ease of mobilization. Unfortunately, due to easiness of construction method, that hollow is casted after being placed. Research has been done to find an easy method of construction to maintain that hollow so that concrete volume can be reduced.

Experimental studies have been conducted. There are six (6) reinforced concrete beams of 200 x 400 x 3850 mm with two different concrete quality of K-300 and K-400 have been tested. Three (3) of those specimens are solid reinforced concrete beams with concrete quality of K-400 is used as benchmark beam. Four point loading test was chosen to investigate flexural behavior of the beams. The test results were analyzed based on graphical relationship between load – displacement, moment - rotation at beam midspan, and the crack pattern of each specimen.

The results showed that flexural strength of HCB K-400 is 0.98 times of solid beam with similar concrete quality. HCB K-300 has flexural strength of 0.965 compared to HCB K-400. The research gives an overview of the making process of cast in site HCB that can be applied in construction site."