A simple fraction-collecting machine for chromatographic analysis

1949 ◽  
Vol 68 (7) ◽  
pp. 208-209 ◽  
Author(s):  
F. W. Cuckow ◽  
H. J. C. Harris ◽  
F. E. Speed
Keyword(s):  
Chromatographic Analysis ◽  
Simple Fraction

UPAYA MENINGKATKAN HASIL BELAJAR MATEMATIKA PADA MATERI PECAHAN SEDERHANA MELALUI MEDIA KARTU PECAHAN DI KELAS VI SD NEGERI 011 DESA BARU KECAMATAN SIAK HULU

2019 ◽  
Vol 3 (1) ◽  
pp. 213
Author(s):  
Maimun Maimun
Keyword(s):  
Action Research ◽  
Learning Outcomes ◽  
Mathematics Learning ◽  
Simple Fraction ◽  
Average Value ◽  
The Subject ◽  
Classroom Action Research

The background of this study is the low mathematics learning outcomes of class VI students at SD Negeri 011 Desa Baru, to overcome this problem a classroom action research was conducted by applying fraction card media. This research was conducted in SD Negeri 011 Desa Baru, the subject of this study was class VI students with a total of 24 students. The results of this study show that mathematics learning outcomes have increased in pre-cycle average value obtained is 59.8, in the first cycle obtained an average value of 68.3. And in the second cycle obtained an average value of 82.9. Based on the results of this study, it can be concluded that the mathematics learning outcomes in simple fraction material increase after the fraction card media are applied.

On the effect of the periodicity of diagnostic measurements on improving the reliability of high-voltage transformers

2019 ◽  
Vol 12 (1) ◽  
pp. 18-21
Author(s):  
V. A. Tikhonov
Keyword(s):  
Service Life ◽  
High Voltage ◽  
Chromatographic Analysis ◽  
Aluminum Industry ◽  
Early Stage ◽  
Diagnostic Methods ◽  
Transformer Oil ◽  
Operating Voltage ◽  
Dissolved Gases ◽  
The Aluminum Industry

The influence of the periodicity of diagnostic measurements on the operational state of high-voltage transformers is considered. Examples of defects of switching devices of converter transformers and methods for their detection are given. The rationale for the importance of recognition of defects at an early stage of their occurrence is given. The influence of the multiplicity of overvoltages on the service life of converter transformers in the aluminum industry is investigated. Based on the analysis of the service life of converter transformers of one of the powerful aluminum plants, where 83% of converter transformers have exhausted their standard service life, it is shown that in 40% of cases it would be possible to avoid their failures, with timely detection and elimination of emerging defects. Examples of defects of OLR (on-load regulators) of converter transformers and methods for their detection are given. The importance of recognition of defects at an early stage of their occurrence is substantiated. A method for chromatographic analysis of dissolved gases in transformer oil has been developed for the qualitative determination of defects and ways to eliminate them. Examples of diagnostics of converter transformers at operating voltage and working load are given, providing the best quality operational characteristics of converter transformers. The periodicity of diagnostic measurements and the reduction of defects and failures has been substantiated. The question of diagnosing the state of the converter transformer TDNP-40000/10 at an enterprise of the aluminum industry is investigated. Currently, diagnostic methods are being developed based on chromatographic analysis of dissolved gases in transformer oil. The presented method of evaluating the operating parameters of transformers allows for the safe operation of high-voltage transformers and enables to increase the reliability of the power supply scheme of aluminum industry plants.

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