CONTROL SYSTEM FOR COMPLETE BURNING IN FURNACE USING LAMBDA PROBE

The objective of this work was to evaluate the biomass burning process in a furnace, using chip as a raw material and an oxygen sensor (lambda probe) to monitor the percentage of oxygen in the gases exhausted during combustion, aiming to maintain the percentage of the coefficient of excess air (α) in the operating range of 1.20 to 1.25%, considered ideal for the biomass (chip) used in the study. Once the excess air is identified at the upper furnace exit, the air entrance in the system will be closed by means of a butterfly valve using a servo motor driven by a Programmable Logic Controller (PLC). The valve was opened or closed according to the oxygen level; when it was lower than 1.20%, the door remained open, and it was closed when the level reached 1.25%, finishing the cycle of the process. The open and closed states of the valve occurred by means of two reed switch magnetic key sensors installed in the air intake system. For the control, monitoring and data acquisition, a supervisory system created using the Elipse SCADA software was used so it was possible to obtain a system database, which will provide important information to maximize the efficiency of the furnace.

Measurement of O2 in the Combustion Chamber of Apulverized Coal Boiler

Operational measurements of the O2 concentration in the combustion chamber of a pulverized coal boiler are not yet common practice. Operators are generally satisfied with measuring the O2 concentration in the second pass of the boiler, usually behind the economizer, where a flue gas sample is extracted for analysis in a classical analyzer. A disadvantage of this approach is that there is a very weak relation between the measured value and the condition in specific locations in the fireplace, e.g. the function of the individual burners and the combustion process as a whole. A new extractionline was developed for measuring the O2 concentration in the combustion chamber. A planar lambda probe is used in this approach. The extraction line is designed to get outputs that can be used directly for diagnosis or management of the combustion in the boiler.

Optimal Combustion Conditions for a Small-scale Biomass Boiler

This paper reports on an attempt to achieve maximum efficiency and lowest possible emissions for a small-scale biomass boiler. This aim can be attained only by changing the control algorithm of the boiler, and in this way not raising the acquisition costs for the boiler. This paper describes the experimental facility, the problems that arose while establishing the facility, and how we have dealt with them. The focus is on discontinuities arising after periodic grate sweeping, and on finding the parameters of the PID control loops. Alongside these methods, which need a lambda probe signal for proper functionality, we inroduce another method, which is able to intercept the optimal combustion working point without the need to use a lambda sensor.

Acquired homozygosity of the rearranged bcr allele during the acute leukemic phase of a patient with Ph-negative chronic myeloid leukemia

A 45-year-old male patient with Ph-negative chronic myeloid leukemia (CML) had rearranged bcr-3′ and bcr-5#x2032; gene regions in Southern blot studies when leukemia was diagnosed. During development of terminal blast crisis, successive blood samples showed a progressive decrease in the amount of germline bcr DNA and its complete loss by full blast crisis. There were also increased amounts of rearranged bcr DNA consistent with acquired homozygosity. A similar result was obtained with an IgV lambda probe and indicated homozygosity of a significant part of chromosome 22. The bcr-abl gene complex behaves as a somatic dominant in CML, and we suggest that its acquired homozygosity is a mechanism of bcr-abl amplification similar to duplication of the Ph chromosome commonly found in the blast crisis of CML.

Acquired homozygosity of the rearranged bcr allele during the acute leukemic phase of a patient with Ph-negative chronic myeloid leukemia

A 45-year-old male patient with Ph-negative chronic myeloid leukemia (CML) had rearranged bcr-3′ and bcr-5#x2032; gene regions in Southern blot studies when leukemia was diagnosed. During development of terminal blast crisis, successive blood samples showed a progressive decrease in the amount of germline bcr DNA and its complete loss by full blast crisis. There were also increased amounts of rearranged bcr DNA consistent with acquired homozygosity. A similar result was obtained with an IgV lambda probe and indicated homozygosity of a significant part of chromosome 22. The bcr-abl gene complex behaves as a somatic dominant in CML, and we suggest that its acquired homozygosity is a mechanism of bcr-abl amplification similar to duplication of the Ph chromosome commonly found in the blast crisis of CML.

A new variable region in mouse immunoglobulin lambda light chains.

A series of lambda+ murine hybridomas were derived from a BALB/c mouse after a single injection of anti-lambda 2 antibodies coupled to LPS. Nine lambda B cell clones (five lambda 2 and four lambda 3) were expected and seven reacted with antibodies specific for the C lambda 2 constant region but showed a particular isoelectric spectrum. Their RNA products did not hybridize with the V lambda probe. The partial DNA sequence of gene segments coding the unexpected light chain of one hybridoma shows that the V gene segment has only 55% homology with the V lambda 2 gene segment sequence and that J lambda 2 and probably C lambda 2 gene segments are used. Taken together, these results demonstrate the existence of a new lambda light chain.