Kapal Selam Antiradar Rp 1,77 Triliun

Oleh Eric Pfeiffer, The Sideshow

Salah satu direktorat di Kementerian Pertahanan Amerika Serikat akan melelang kapal selam siluman terkenalnya Sea Shadow. Kapal selam antiradar ini sudah menghabiskan dana $195 juta (Rp 1,77 triliun) dalam pengembangannya. Meski pelelangannya dibuka pada harga $50 ribu (Rp 455,3 juta) dan butuh uang muka $10 ribu (Rp 91 juta).

The Courier Mail melaporkan bahwa kapal itu jadi populer setelah menginspirasi rumah penjahat James Bond di film “Tomorrow Never Dies”.

Kapal selam antiradar senilai $195 juta. (Kementerian Pertahanan AS)

Lelang Kementerian Pertahanan AS dijadwalkan berakhir Kamis ini. Saat ini harga tertinggi untuk kapal selam ini adalah $100 ribu (Rp 910,7 juta)

Sayangnya, sebelum Anda menjadi penjahat James Bond dengan memiliki kapal selam ini, ada satu hal yang harus Anda perhatikan: Kapal selam ini akan dipreteli dan dihancurkan sebelum diberikan ke pemenang lelang.

“Kapal selam bekas Sea Shadow akan dipreteli sepenuhnya dan dihancurkan dalam wilayah Amerika Serikat,” tulis penjelasan di situs direktorat Kementerian Pertahanan tersebut. “Dipreteli berarti mengurangi volume properti tersebut sampai tidak memiliki nilai selain materinya.”

Kapal selam uji coba sepanjang 49,9 meter ini pertama dibangun pada 1983 oleh Lockheed untuk Angkatan Laut AS. Kapal ini memiliki teknologi antiradar atau siluman yang sama seperti pesawat siluman AS. Meski terlihat ringkih, kapal selam ini memiliki dua pemecah ombak di bawah laut dan dirancang khusus agar tahan menghadapi ombak yang mencapai tinggi 5,4 meter.

Bagaimana Bila ada Pembangunan Jembatan Selat sunda?

Liputan6.com, Jakarta: Menko Polhukam menggelar rapat koordinasi dengan sejumlah kementerian dan lembaga pemerintah terkait pembangunan Jembatan Selat Sunda, Senin (9/1). Dari pembahasan awal itu, semua peserta rapat menyetujui proyek pembangunan jembatan tersebut. Read the rest of this entry »

Sifat – Sifat air

Air sering disebut sebagai sumber kehidupan.  Sebuah ungkapan yang tidak berlebihan, karena kita ketahui bahwa semua makhluk hidup memiliki ketergantungan terhadap air. Sebenarnya, apa yang membuat air begitu spesial? Berikut beberapa sifat air yang penting bagi kehidupan.

 

water1Air mempunyai tiga fase: cair, gas, dan padatan. Dapat dengan mudah berubah fase dalam dalam rentang temperature yang ada di permukaan bumi. Siklus air global didasarkan pada tiga fase air tersebut.

Read the rest of this entry »

finite volume method (FVM)

The finite volume method is a method for representing and evaluating partial differential equations in the form of algebraic equations [LeVeque, 2002; Toro, 1999]. Similar to the finite difference method or finite element method, values are calculated at discrete places on a meshed geometry. “Finite volume” refers to the small volume surrounding each node point on a mesh. In the finite volume method, volume integrals in a partial differential equation that contain a divergence term are converted to surface integrals, using the divergence theorem. These terms are then evaluated as fluxes at the surfaces of each finite volume. Because the flux entering a given volume is identical to that leaving the adjacent volume, these methods are conservative. Another advantage of the finite volume method is that it is easily formulated to allow for unstructured meshes. The method is used in many computational fluid dynamics packages.

(source : wikipedia)

finite element method (FEM)

The finite element method (FEM) (its practical application often known as finite element analysis (FEA)) is a numerical technique for finding approximate solutions of partial differential equations (PDE) as well as of integral equations. The solution approach is based either on eliminating the differential equation completely (steady state problems), or rendering the PDE into an approximating system of ordinary differential equations, which are then numerically integrated using standard techniques such as Euler’s method, Runge-Kutta, etc.

In solving partial differential equations, the primary challenge is to create an equation that approximates the equation to be studied, but is numerically stable, meaning that errors in the input and intermediate calculations do not accumulate and cause the resulting output to be meaningless. There are many ways of doing this, all with advantages and disadvantages. The Finite Element Method is a good choice for solving partial differential equations over complicated domains (like cars and oil pipelines), when the domain changes (as during a solid state reaction with a moving boundary), when the desired precision varies over the entire domain, or when the solution lacks smoothness. For instance, in a frontal crash simulation it is possible to increase prediction accuracy in “important” areas like the front of the car and reduce it in its rear (thus reducing cost of the simulation). Another example would be in Numerical weather prediction, where it is more important to have accurate predictions over developing highly-nonlinear phenomena (such as tropical cyclones in the atmosphere, or eddies in the ocean) rather than relatively calm areas.

(source : wikipedia)

Sejarah Kapal TITANIC

Sejarah Kapal Titanic – Semua orang pasti tahu dan pernah nonton Titanic, menarik bukan? Aslinya, Titanic sendiri merupakan kapal penumpang milik White Star Line, dibangun di galangan kapal Harland and Wolff di Belfast, Irlandia Utara, didisain untuk menyaingi Lusitania dan Mauretania milik Cunard Line. Titanic, bersama kapal saudara kembarnya Olympic, Olympic dan yang akan dibuat Britannic (pada awalnya dinamakan Gigantic, bertujuan menjadi kapal paling mewah dan terbesar yang pernah dibuat. Read the rest of this entry »

Refrensi Perkapalan

Beberapa Buku Refrensi Design Kapal :

1. RAWSON, K. J. (2001). Basic Ship Theory 1.

2. RAWSON, K. J. (2001). Basic Ship Theory 2.

3. Practical Ship Hydrodynamics

4. Intro_to_Naval_Architecture_3E

Apa Itu CFD?

Imagine that you are an aeronautical engineer in the later 1950s. You have been
given the task of designing an atmospheric entry vehicle—in those days it would
have been an intercontinental ballistic missile. (Later, in the early 1960s, interest
also focused on manned atmospheric entry vehicles for orbital and lunar return missions.)
You are well aware of the fact that such vehicles will enter the earth’s atmosphere
at very high velocities, about 7.9 km/s for entry from earth orbit and about
11.2 km/s for entry after returning from a lunar mission. At these extreme hypersonic
speeds, aerodynamic heating of the entry vehicle becomes very severe, and is
the dominant concern in the design of such vehicles.

DAPAT DIDOWNLOAD DISINI.

FINITE DIFFERENCE, FINITE ELEMENT AND FINITE VOLUME METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS

There are three important steps in the computational modelling of any
physical process: (i) problem definition, (ii) mathematical model, and
(iii) computer simulation.
The first natural step is to define an idealization of our problem of
interest in terms of a set of relevant quantities which we would like to measure.
In defining this idealization we expect to obtain a well-posed problem,
this is one that has a unique solution for a given set of parameters. It might not
always be possible to guarantee the fidelity of the idealization since, in some
instances, the physical process is not totally understood. An example is the
complex environment within a nuclear reactor where obtaining measurements
is difficult.

DAPAT DI DOWLOAD DISINI.

Catamaran Concepts : Vessel Stability

If the definition required only that an object float for it to be considered a “boat”, things would be a lot easier for the boat designer. Observe to what lengths he must go to in fact before he can claim enough proficiency in the field to be published.

Producing an attractive bow wave is the first thing he should always consider, then the flag halyard. Once these requirements have been satisfied, he can progress with confidence to considering the vessel’s stability, or its inclination to stay floating right side up. (Presenting a sober and thoughtful visage is essential at all times to reassure your backers.) Read the rest of this entry »

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