ANALISA LINEAR SUPERPOSITION DALAM KELOLA GETARAN TANAH HASIL PELEDAKAN PADA PERTAMBANGAN BATUBARA

ABSTRAK Getaran tanah merupakan getaran yang ditimbulkan akibat dari proses peledakan tambang. Selama ini getaran tanah dianggap sebagai waste energy yang dapat merusak dan menjadi isu terhadap lingkungan di sekitar area tambang. PT. Multi Nitrotama Kimia sebagai perusahaan jasa peledakan dan penjualan bahan peledak di Indonesia memiliki kustomer dengan isu demikian, salah satunya adalah PT Adaro Indonesia. Guna menanggulangi isu tersebut, maka dilakukan rekayasa teknik terhadap getaran tanah yang dihasilkan dengan merubah waste energy menjadi work energy dengan prinsip linear superposition menggunakan metode signature hole analysis (SHA) dan dioptimalkan dengan aplikasi inter-deck delay pada lubang double-deck untuk meminimalisir getaran tanah yang ditimbulkan. Penelitian dan percobaan dilakukan menggunakan metode Signature Hole Analisys (SHA) untuk merekam perambatan gelombang di setiap range blok – strip tertentu terhadap area konsen. Gelombang yang telah terekam selanjutnya dianalisis dengan fitur Linear Superposition untuk mendapatkan rekomendasi waktu tunda beserta prediksi getaran yang ditimbulkan. Rekomendasi waktu tunda yang didapat adalah waktu tunda pada inter-hole, inter-row, dan inter-deck yang mana akan diterapkan untuk peledakan selanjutnya. Berdasarkan analisis menggunakan metode Signature Hole Analysis, rekomendasi waktu tunda yang diberikan dapat diterapkan untuk mengakomodir prinsip linear superposition gelombang. Penerapannya dapat dioptimalkan menggunakan inter-deck delay sehingga meminimalisir getaran tanah yang dihasilkan. Dibuktikan oleh getaran tanah yang dihasilkan menggunakan rekomendasi tersebut selalu di bawah standar yang ditetapkan (PVS = < 2.00 mm/s). Kaca Kunci : Getaran Tanah, Signature Hole Analysis, Linear Superposition ABSTRACT One of the blasting process effect is ground vibration. Ground vibration currently consider as waste energy which it can infere and be an issue to the environment. PT. Multi Nitrotama Kimia as blasting service company and explosives sales in Indonesia has customers dealing with that issues, one of them is PT Adaro Indonesia. To overcome the issue, engineering approach is done to the ground vibration by changing waste energy into work energy with the principle of linear superposition using the signature hole analysis (SHA) method and optimized with the application of inter-deck delay on the double-deck hole to minimize the ground vibration. Researches and experiments are carried out using the Signature Hole Analysis (SHA) method to record wave propagation in each range of certain blocks - strips to the concern area. The recorded waves are analyzed with the Linear Superposition feature to obtain delay time recommendation along with the predicted vibration. The recommended delay time obtained is the delay time on inter-hole, inter-row, and inter-deck which will be applied for next blasting. Based on the Signature Hole Analysis method, the recommended delay time given can be applied to accommodate the linear superposition wave principle. Its application can be optimized using inter-deck delay to minimize ground vibration produced. Its proven by ground vibrations produced using the recommendations always below the specified standard (PVS = <2.00 mm / s). Keywords: Ground Vibration, Signature Hole Analysis, Linear Superposition

Linier Superposition Analysis on Managing Blasting Ground Vibration in Coal Mining

One of the blasting process effect is ground vibration. Ground vibration currently consider as waste energy which it can infere and be an issue to the environment. PT. Multi Nitrotama Kimia as blasting service and explosives sales in Indonesia has customers dealing with that issues, one of them is PT Adaro Indonesia. To overcome the issue, engineering approach is done to the ground vibration by changing waste energy into work energy with the principle of linear superposition using the signature hole analysis (SHA) method to minimize the ground vibration. Researches and experiments are carried out using the Signature Hole Analysis (SHA) method to record wave propagation in each range of certain blocks - strips to the concern area. The recorded waves are analyzed with the Linear Superposition feature to obtain delay time recommendation along with the predicted vibration. The recommended delay time obtained is the delay time on inter-hole and inter-row which will be applied for next blasting.Based on the Signature Hole Analysis method, the recommended delay time given can be applied to accommodate the linear superposition wave principle. Its application can be optimized using inter-deck delay to minimize ground vibration produced. Its proven by ground vibrations produced using the recommendations always below the specified standard (PVS = &#60;2.00 mm / s).

Failure Analysis for a Low Pressure Aeroengine Turbine Vane

Background & Objective In this work, a thermo-mechanical fatigue application related to a fracture process simulation in a turbine vane is implemented, using a submodelling approach based on the principle of linear superposition. Method The proposed crack propagation approach leverages on a combined use of FEM and DBEM methodologies: the global analysis is solved by using FEM whereas the fracture problem is demanded to DBEM. In particular, a DBEM submodel is extracted from a global uncracked FE model and, in the new proposed formulation, boundary conditions are applied just on crack faces rather than loading subdomain boundaries with displacements/tractions and temperatures, as in the classical approach. Results & Conclusion The adopted approach solves the fracture problem by using simpler pure stress analyses rather than by thermal-stress analyses, as requested by the classical approach. Boundary conditions applied on the submodel crack faces come from the solution of a FE uncracked global model. The computational advantages of such alternative approach are highlighted and, in addition, a fatigue assessment is provided for a turbine vane, considering as initial crack the maximum design defect dictated by GE-Avio regulations for such kind of components.

CALCULATING THE POSITRON – ELECTRON CORRELATION ENERGY IN ZnO WITH THE MODIFIED SINGLE WAVE FUNCTION FOR POSITRON

The ZnO – positron system is studied and its positron – electron correlation energy is estimated in its ground state. The positron binds with the outer shell electrons of Zinc and Oxigen to form the pseudo ZnO – positron molecule before it anihilates with one of these electrons. In this work, the single wave function for positron is modified according to the principle of linear superposition, and by using Variational Quantum Monte – Carlo method (VQMC) the correlation energy of this system is estimated with the value Ec e-p = - 9.3 ± 1.1 eV. It turns out that the value is closer to results estimated by other methods than the value that we had done before.

INVESTIGATION OF SUITABILITY FOR THE LINEAR SUPERPOSITION MODEL

An aircraft model was tested at the 3-meter low speed wind tunnel as it was oscillated with large amplitude. The unsteady aerodynamic behavior was acquired during the oscillation in yawing, rolling and yawing-rolling. The lateral-directional dynamic derivative was obtained using the mathematic model of unsteady aerodynamics and the dynamic derivative simulation. According to the principle of linear superposition, the unsteady aerodynamic parameters of the model about yaw-roll coupled motion can be obtained by the quasi-steady aerodynamic model and the result was compared with the experimental test. It was found that for the quasi-steady aerodynamic model the unsteady aerodynamic characteristic was in agreement with the test at the middle and large angle of attack (for example α ≤ 45°), but was opposite at the extremely large angle of attack (α > 45°).

Second-Order Directional Seas and Associated Wave Forces

Most methods for wave force computation incorporate either the nonlinearities of the ocean surface for a single fundamental component or the random and/or directional characteristics using superposition of linear wave components. One exception is the intuitive "hybrid" method, which combines elements of linear and nonlinear waves. This paper describes and applies a method correct to the second order in wave height for calculating waves and wave forces caused by a directional wave spectrum on an offshore structure.Starting with a prescribed linear spectrum of directional waves, a set of random phases is generated and the second-order spectrum computed with phases defined by all contributing pairs of first-order components. Thus, with one realization of the spectrum complete up to the second order, the wave profile and water particle kinematics can be profile and water particle kinematics can be simulated in the time domain. The wave forces also are computed in the time domain, taking full account of their nonlinear and directional properties. The resulting wave forces at any level vary in direction and magnitude. The total wave forces summed over all piling of a structure are less than those for a unidirectional train of waves with the same one-dimensional spectrum.Several examples are presented to illustrate reductions in maximum wave forces caused by the directional distribution of waves. We found that for a single piling the maximum force decreases by a factor ranging from 1.0 to 0.61 as the directional spread increases from unidirectional to uniformity over a half plane. For a four-pile group on a square array of 300-ft (91.4-m) spacing, the corresponding decrease in the factor is 1.0 to 0.51 for a Bretschneider spectrum with a peak period of approximately 12 seconds. The results of this complete model are compared with the more intuitive and approximate hybrid method and are found to agree quite well. Force spectra are presented and discussed for the inline and transverse directions. Introduction The nonlinearity, randomness, and directionality of a real sea preclude a simple but realistic determination of wave loading on a single- or multiple-pile group. Presently, there are two essentially different but complementary methods for computing wave loadings. One method represents nonlinearities of a single wave composed of a characteristic fundamental period and its higher harmonics. A number period and its higher harmonics. A number of such theories have been-developed. Dalrymple extended the stream function approach of Dean, to waves on a shear current. Some of these theories adequately account for the nonlinearities; however, they avoid the random and directional characteristics of the sea surface. The second method uses the principle of linear superposition of an infinite principle of linear superposition of an infinite number of waves with given frequencies, amplitudes, and directions of propagation but independent phases; the total energy is distributed over a phases; the total energy is distributed over a continuum of frequencies and directions. In this manner, a three-dimensional Gaussian sea can be represented fully. However, ignoring the nonlinearities makes the random Gaussian model unrealistic - especially for large waves. SPEJ P. 129

Synthesis of Seven-Link Mechanisms

The mechanisms derived from the seven-link chains with five links in their two loops and having two degrees of freedom are examined for six synthesis problems. Using displacement matrices, closed form synthesis equations are derived. It is shown that three synthesis problems may be solved using the principle of linear superposition, and closed form solutions may be obtained. The other three synthesis problems involve highly nonlinear equations and must be solved numerically.

A Study of Midship Bending Moments in Irregular Head Seas

In this article an exploratory study on behalf of the S-3 Panel of The Society of Naval Architects and Marine Engineers is reported, in which the statistical characteristics of model bending moments in irregular head seas have been predicted on the basis of the principle of linear superposition of responses to the component waves. It is shown that for the case of a T2-SEA1 tanker model, agreement between predicted and observed bending moments in irregular waves is reasonably good. The method is then applied to predicting the trend of bending moments with severity of sea and speed of ship.