Effect of Compression Ratio on LNG Exchanger for Single Mixed Refrigerant Plant

2014 ◽  
Vol 1 (1) ◽  
pp. 015-020
Author(s):  
Tuka Kuru ◽  
Keyword(s):  
Author(s):  
Serhii Kovalov

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.


2017 ◽  
Vol 13 (10) ◽  
pp. 6552-6557
Author(s):  
E.Wiselin Kiruba ◽  
Ramar K.

Amalgamation of compression and security is indispensable in the field of multimedia applications. A novel approach to enhance security with compression is discussed in this  research paper. In secure arithmetic coder (SAC), security is provided by input and output permutation methods and compression is done by interval splitting arithmetic coding. Permutation in SAC is susceptible to attacks. Encryption issues associated with SAC is dealt in this research method. The aim of this proposed method is to encrypt the data first by Table Substitution Box (T-box) and then to compress by Interval Splitting Arithmetic Coder (ISAC). This method incorporates dynamic T-box in order to provide better security. T-box is a method, constituting elements based on the random output of Pseudo Random Generator (PRNG), which gets the input from Secure Hash Algorithm-256 (SHA-256) message digest. The current scheme is created, based on the key, which is known to the encoder and decoder. Further, T-boxes are created by using the previous message digest as a key.  Existing interval splitting arithmetic coding of SAC is applied for compression of text data. Interval splitting finds a relative position to split the intervals and this in turn brings out compression. The result divulges that permutation replaced by T-box method provides enhanced security than SAC. Data is not revealed when permutation is replaced by T-box method. Security exploration reveals that the data remains secure to cipher text attacks, known plain text attacks and chosen plain text attacks. This approach results in increased security to Interval ISAC. Additionally the compression ratio  is compared by transferring the outcome of T-box  to traditional  arithmetic coding. The comparison proved that there is a minor reduction in compression ratio in ISAC than arithmetic coding. However the security provided by ISAC overcomes the issues of compression ratio in  arithmetic coding. 


Author(s):  
M. A. Danilov ◽  
◽  
M. V. Drobysh ◽  
A. N. Dubovitsky ◽  
F. G. Markov ◽  
...  

Restrictions of emissions for civil aircraft engines, on the one hand, and the need in increasing the engine efficiency, on the other hand, cause difficulties during development of low-emission combustors for such engines.


Author(s):  
Hikka Sartika ◽  
Taronisokhi Zebua

Storage space required by an application is one of the problems on smartphones. This problem can result in a waste of storage space because not all smartphones have a very large storage capacity. One application that has a large file size is the RPUL application and this application is widely accessed by students and the general public. Large file size is what often causes this application can not run effectively on smartphones. One solution that can be used to solve this problem is to compress the application file, so that the size of the storage space needed in the smartphone is much smaller. This study describes how the application of the elias gamma code algorithm as one of the compression technique algorithms to compress the RPUL application database file. This is done so that the RPUL application can run effectively on a smartphone after it is installed. Based on trials conducted on 64 bit of text as samples in this research it was found that compression based on the elias gamma code algorithm is able to compress text from a database file with a ratio of compression is 2 bits, compression ratio is 50% with a redundancy is 50%. Keywords: Compression, RPUL, Smartphone, Elias Gamma Code


Author(s):  
Winda Winda ◽  
Taronisokhi Zebua

The size of the data that is owned by an application today is very influential on the amount of space in the memory needed one of which is a mobile-based application. One mobile application that is widely used by students and the public at this time is the Complete Natural Knowledge Summary (Rangkuman Pengetahuan Alam Lengkap or RPAL) application. The RPAL application requires a large amount of material storage space in the mobile memory after it has been installed, so it can cause this application to be ineffective (slow). Compression of data can be used as a solution to reduce the size of the data so as to minimize the need for space in memory. The levestein algorithm is a compression technique algorithm that can be used to compress material stored in the RPAL application database, so that the database size is small. This study describes how to compress the RPAL application database records, so as to minimize the space needed on memory. Based on tests conducted on 128 characters of data (200 bits), the compression results obtained of 136 bits (17 characters) with a compression ratio is 68% and redundancy is 32%.Keywords: compression, levestein, aplication, RPAL, text, database, mobile


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hüseyin Pelit ◽  
Fatih Emiroglu

AbstractIn this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.


Author(s):  
Dibo Pan ◽  
Haijun Xu ◽  
Bolong Liu ◽  
Congnan Yang

The sealing characteristics of an annular power cylinder based on the Twin-rotor piston engine are studied, which provides a theoretical foundation for the sealing design of a new high-power density piston engine. In this paper, the basis thermodynamic realization process of an annular power cylinder is presented. The Runge Kutta equation is used to establish the coupled leakage model of adjacent working chambers under annular piston seal. And the sealing performance of the annular power cylinder is analyzed in detail. Moreover, the influence of rotor speed and compression ratio on the sealing characteristics and leakage is studied. Finally, some tests are carried out to verify the sealing principle and simulation results, which verifies the theoretical basis of simulation analysis. Results show that there are double pressure peaks in the leakage chamber between two working chambers, which is beneficial to reduce the leakage rate. Besides, increasing the speed and decreasing the compression ratio can help to reduce gas leakage. Furthermore, the effects of speed variation on the leakage are only significant when rotating at low speed. Changing the compression ratio has a greater effect on the slope of the leakage curve at a low compression ratio, and the lower the compression ratio, the better the sealing effect.


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