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"In this paper, we perform combination methods of semi-empirical research, a theoretical approach, and force-matching to determine the optimum adsorption capacity on an open-ended single-walled carbon nanotube (SWCNT) as a diameter function. Using a semi-empirical study, we can determine the value of monolayer coverage and isosteric heat of adsorption from available thermodynamic data. By completing the semi-empirical study, we carried out quantum mechanical calculations to determine the adsorption energy on the interior and exterior of SWCNTs. Furthermore, monolayer coverage, specific surface area, and maximum adsorption capacity as the main quantity in the adsorption process was estimated using the combination method of force-matching and a classical Lennard-Jones potential model. Hydrogen physisorption was investigated on zig-zag SWCNTs at conditions for a pressure range of 0.1 to 10 MPa at 233 K and 298.15 K temperature. The adsorption of all data can be explained with the Toth model. The results shows the SWCNT exterior physisorption energy range between 1.35 to 1.62 kcal/mol. The interior range from 1.22 to 2.43 kcal/mol. With a wide degree of temperature and pressure variations, we obtained an optimum SWCNT diameter of 8-12 Å . At the optimum diameter maximum adsorption capacity, we achieved 1.75 wt% at 233 K and an operating pressure of 10 MPa."

"ABSTRAKPenelitian ini membandingkan konvergensi elemen pelat lentur triangular yaitu MITC3, DKMT, DST-BL, dan DST-BK. Keempat elemen tersebut sama-sama memiliki 9-derajat kebebasan namun dengan formulasi regangan lentur dan regangan geser yang berbeda. Masing-masing elemen akan diuji pada beberapa kasus homogen isotrop, yaitu kasus pelat bujursangkar, pelat melingkar, pelat Razzaque, dan pelat Morley, dengan berbagai variasi ketebalan dan mesh. Keluaran uji numerik pelat homogen isotrop yang dibandingkan berupa perpindahan, momen arah-x dan momen arah-y, serta energi. Selain kasus homogen isotrop, masing-masing elemen diuji pada kasus komposit, yaitu berupa uji dari Srinivas. Dari keempat elemen yang diuji, elemen MITC3 memiliki tingkat konvergensi yang lebih lambat dibandingkan dengan elemen lainnya. Dari segi waktu komputasi, elemen MITC3 dan DKMT memiliki waktu komputasi yang lebih singkat dibandingkan dengan elemen DST-BL dan DST-BK.

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ABSTRACTThis research compare the convergence of triangular plate bending element MITC3, DKMT, DST BL, and DST BK. These elements has 9 degrees of freedom with different formulation for bending strain and shear strain interpolation. Each element is tested for several benchmark problem of isotropic condition square plate problem, circular plate problem, Razzaque skew plate, and Morley plate. The output of homogen isotropic problem is vertical displacement, moment in x direction, moment in y direction, and energy. For composite condition, numerical test is conducted for Srinivas test. In most benchmark test, MITC3 has slower convergence compared with the other elements. But on the other side, MITC3 and DKMT elements have relatively short computational time compared with DST BL and DST BK. "

"Teori elemen cangkang s T3γ 18merupakan elemen triangular 3-nodal dengan 18 derajat kebebasan yang dikembangkan dari teori elemen pelat dan cangkang Reissner-Mindlin. Pengembangan teori elemen s T3γ 18 dilakukan pada struktur komposit yang memperhitungkan deformasi geser transversal dan energi pengaruh membran-lentur. Tujuan dari penelitian ini adalah mengembangkan elemen s T3γ 18 pada struktur cangkang komposit dan membandingkan terhadap solusi referensi dan elemen DKMT, DKMQ, maupun MITC4. Beberapa kasus uji numerik untuk pelat isotrop antara lain pelat persegi, pelat Morley, pelat Razzaque, pelat melingkar, curved beam. Pada kasus cangkang isotrop yaitu kasus twisted beam, Scordelis-Lo roof, kasus Hook, pinched cylindrical shell, hyperbolic paraboloid shell, hemisphere shell, dan hyperboloid shell. Sedangkan pada kasus komposit uji numerik yang dilakukan adalah kasus pelat persegi dan cylindrical shell.

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The shell element theory is a 3-node triangular element with 18 degrees of freedom developed based on Reissner-Mindlin theory of plate and shell elements. The development of element theory is carried out on composite structures that determine transverse shear deformation and membrane-bending energy effects. The purpose of this study was to develop elements in the composite shell structure and compare the reference solutions and elements of DKMT, DKMQ, and MITC4. The numerical tests for isotropic plates and shell are square plate, Morley plate, Razzaque plate, circular plate, and curved beam, Scordelis-Lo roof, Hook problem, pinched cylindrical shell, hyperbolic parabolic shell, hemisphere shell, and hyperboloid shell. And the numerical test for composite are square plate and cylindrical shell."

"The book presents homogeneous solutions in static and dynamical problems of anisotropic theory of elasticity, which are constructed for a hollow cylinder. It also offers an asymptotic process for finding frequencies of natural vibrations of a hollow cylinder, and establishes a qualitative study of several applied theories of the boundaries of applicability.Further the authors develop a general theory for a transversally isotropic spherical shell, which includes methods for constructing inhomogeneous and homogeneous solutions that allow the characteristic features of the stress-strain state of an anisotropic spherical shell to be revealed. Lastly, the book introduces an asymptotic method for integrating the equations of anisotropic theory of elasticity in variable thickness plates and shells."

"DKMT adalah elemen pelat triangular dengan 3 DOF pada tiap nodalnya. Elemen ini merupakan elemen dengan pendekatan diskrit yang berdasarkan teori pelat Reissner-Mindlin. Tulisan ini akan mengevaluasi kinerja dari elemen DKMT pada kasus pelat melingkar dengan material isotrop homogen dua metode konvergensi, yaitu konvergensi klasik dan konvergensi r-norm dan hasilnya akan diperbandingkan dengan T3gs.

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DKMT is a triangular plate element with 3 DOF in each nodal. This element is an element with a discrete approach based on Reissner-Mindlin plate theory. This paper will evaluate the performance of DKMT elements in the case of circular plates with homogeneous isotropic materials of two convergence methods, namely classical convergence and r-norm convergence and the results will be compared with T3gs."

"Sambungan kunci geser baja merupakan sambungan dimana kunci geser tersebut terdiri dari dua (2) bagian yaitu key male dan key female. Sambungan ini terdapat pada sambungan jembatan yang menggunakan beton pracetak segmental. Kunci geser ini berfungsi untuk mentransfer kedua gaya baik gaya lateral dan gaya vertikal ke sambungan serta untuk mencegah terjadinya perpindahan vertikal antara elemen-elemen pada sambungan sehingga kunci geser ini menjadi seperti pengunci pada gelagar jembatan. Kajian ini bertujuan untuk mendapatkan gambaran mengenai besar beban potensi retak dengan variasi yang digunakan adalah mutu betonnya, mutu baja lunak, diameter kunci geser, gaya prategang pada beton, serta jumlah kunci geser. Pada permodelan ini menggnakan dua tipe permodelan.Permodelan tipe 1 menggunakan data-dat linear elastis, sedangkan permodelan tipe 2 menggunakan data-data multilinier isotropic hardening.Hasil simulasi menunjukkan bahwa variasi mutu terbesar, dengan diameter 90 mm, dan gaya pratekan sebesar 3,45 MPa yang menghasilkan beban potensi retak terbesar, serta kunci geser dengan jumlah tiga yang menghasilkan beban potensi retak maupun leleh terbesar

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Metal shear key is a joint resembling a key that consist of two parts which are key male and key female. This joint is located as a connection between segmental conceret precast bridge. The function of shear key is to transfer both lateral or vertical forces from the element of bridge to the joint so that shear key could become like a fastener at the girder.

The purpose of the study is to obtain the load related to potential crackfrom the variations of shear key that are quality of the concrete, quality of the mild steel, diameter of shear key, prestress, and the number of shear key. This research uses two type of modelling. The first type using linear elastic data, while the second type uses multilinier isotropic hardening data.

The result of the study shows that the highest quality od concrete and mild steel, with 90 mm diameter, and prestress force is 3,45 MPa producesthe maximumload related to potential crack, and the three shear key also produces both the maximumload related to potential crack and the maximum load related to potential failure for steel."