Burner Performance Evaluation Using Test Code

Development of new burner technology is common practice nowadays. Standardized test codes are available to conduct tests to determine operating characteristics and thermal performance of different parts of steam generating units. This paper describes the results of testing performed to evaluate thermal efficiency of a 74.5?kW fire-tube steam generator fired with a new premixed flame burner in comparison to a typical standard-retrofit diffusion flame burner system. Two premixed flame burners sized at 7.6 and 10.1?cm were tested. Testing was performed in accordance with the ASME PTC 4.1 Power Test Code. The evaluation was conducted in the range of small- to mid-sized, natural gas-fired applications, from 1.06?to?2.64×106?kJ/h. The environmental nitrogen oxide (NOx) emissions performance was also compared for both burner technologies. The results of this evaluation indicate that firing the test boiler with the 7.6?cm new burner slightly improves unit thermal efficiency by 4.0–3.3% for a unit load ranging from approximately 1.06?to?1.79×106?kJ/h, respectively. Operation with the 10.1?cm new burner improves the thermal efficiency by approximately 1.6% at 2.32×106?kJ/h. The uncertainty in the measurements used in the efficiency calculations should account for approximately ±1.5% uncertainty in the reported gross efficiency. Reductions in NOx emissions of the order of 10% resulted from operation with the new premixed flame burners.     

Onr-partition designs in hamming spaces

The concept of the combinatorial matrix of an unrestricted code and the notion of anr-partition design admitted by a code are introduced and discussed in detail. The theory includes a characterization of completely regular codes, and a combinatorial interpretation of the fact that the distinct rows of the distance distribution matrix of a code are linearly independent. In general, it is possible to compute the distance distribution matrix of any code admitting a given partition design by solving a well-defined system of linear equations; this is an efficient technique provided the number of classes in the partition is relatively small.     

Future energy goals for Maryland: Greenhouse gas reductions

Legislative requirements in Maryland set very robust goals for the implementation of energy efficiency by utilities. Significant energy savings has been achieved in all customer sectors and efficiency gains have been made over time in equipment and building construction. Looking forward, utilities should implement programs to promote energy efficiency with a greater emphasis on GHG reductions. Feasibility studies need to occur, but flexibility is key given changing codes and standards and market transformation.     

Weight distribution and dual distance

Several results in coding theory (e.g. the Carlitz-Uchiyama bound) show that the weight distributions of certain algebraic codes of lengthn are concentrated aroundn/2 within a range of width n. It is proved in this article that the extreme weights of a linear binary code of sufficiently high dual distance cannot be too close ton/2, the gap being of order n. The tools used involve the Pless identities and the orthogonality properties of Krawtchouk polynomials, as well as estimates on their zeroes. As a by-product upper bounds on the minimum distance of self-dual binary codes are derived.     

联合信源信道算术码研究

介绍联合信源信道算术码添加禁用符号的编码方法,以实例方式引入联合信源信道算术码的检错原理。综述联合信源信道算术码的检错时延分布、几何分布,分析各种解码方法、序列解码方法及其各种改进,研究基于有限状态机的解码方法与其他信道码构成的迭代式联合解码方法,并展望目前联合信源信道算术码研究存在的问题及其前景。     

Turbo码交织矩阵的一种改进设计

Ｔｕｒｂｏ码以其优异的性能而迅速成为近年来信道编码领域研究的热点。在Ｔｕｒｂｏ码的设计中,交织矩阵是影响其整体性能的重要因素。尤其是在采用小规模交织矩阵时,不同的设计产生的结果差别很大,本文提出一种交织矩阵的改进设计方法,它能够使成员码编码器网络在一帧数据编码结束后全部终结归零,从而为译码判决提供了正确的初始条件,与传统的非全归零交织矩阵相比较,分析结果表明本文提出的设计方案性能更优。３１     

Calculation of fuel burnup and radionuclide inventory in the Syrian miniature neutron source reactor using the GETERA code

Calculations of the fuel burnup and radionuclide inventory in the Syrian miniature neutron source reactor (MNSR) after 10 years (the reactor core expected life) of the reactor operation time are presented in this paper using the GETERA code. The code is used to calculate the fuel group constants and the infinite multiplication factor versus the reactor operating time for 10, 20, and 30 kW operating power levels. The amounts of uranium burntup and plutonium produced in the reactor core, the concentrations and radionuclides of the most important fission products and actinide radionuclides accumulated in the reactor core, and the total radioactivity of the reactor core were calculated using the GETERA code as well. It is found that the GETERA code is better than the WIMSD4 code for the fuel burnup calculation in the MNSR reactor since it is newer, has a bigger library of isotopes, and is more accurate.     

缩短卷积码的仿真实验研究

对缩短卷积码及RCPC码基本原理与应用进行了论述，构建了TETRA系统及CDMA正反向信道的缩短卷码的仿真模型进行了不同编码速率，不同打孔方案的仿真实验，并得出了有参考价值的实验结果。     

一种自适应线性分散码方案的性能研究

针对线性分散码复杂度较高的问题,提出一种自适应线性分散码(ALDC),并将其应用于协作通信网络.该码可以根据当前信道状态,自适应地选择不同的调制阶数和分散矩阵,以在不同信噪比下获得最优的误码率性能,同时降低译码复杂度.分析了该码在协作系统中的编码与译码,并在误比特率性能上与传统空时分组码和LDC进行了仿真对比.结果表明,ALDC的误码率性能要优于传统的正交空时分组码和LDC,且译码复杂度较低.