66. Size-Selective Sampling Using Several Impactors in Parallel

2004 ◽  
Author(s):  
S. Trakumas
Keyword(s):  
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.


2020 ◽  
Vol 22 (39) ◽  
pp. 22289-22301
Author(s):  
Cornelia G. Heid ◽  
Imogen P. Bentham ◽  
Victoria Walpole ◽  
Razvan Gheorghe ◽  
Pablo G. Jambrina ◽  
...  

The ability to orient NO molecules prior to collision with Ar atoms allows selective sampling of different potential energy surface regions and elucidation of the associated collision pathways.


2021 ◽  
Vol 40 (5) ◽  
pp. 9471-9484
Author(s):  
Yilun Jin ◽  
Yanan Liu ◽  
Wenyu Zhang ◽  
Shuai Zhang ◽  
Yu Lou

With the advancement of machine learning, credit scoring can be performed better. As one of the widely recognized machine learning methods, ensemble learning has demonstrated significant improvements in the predictive accuracy over individual machine learning models for credit scoring. This study proposes a novel multi-stage ensemble model with multiple K-means-based selective undersampling for credit scoring. First, a new multiple K-means-based undersampling method is proposed to deal with the imbalanced data. Then, a new selective sampling mechanism is proposed to select the better-performing base classifiers adaptively. Finally, a new feature-enhanced stacking method is proposed to construct an effective ensemble model by composing the shortlisted base classifiers. In the experiments, four datasets with four evaluation indicators are used to evaluate the performance of the proposed model, and the experimental results prove the superiority of the proposed model over other benchmark models.


2021 ◽  
Vol 265 ◽  
pp. 118720
Author(s):  
Jun-Hyung Lim ◽  
Sang Hwan Nam ◽  
Jongwoo Kim ◽  
Nam Hoon Kim ◽  
Gun-Soo Park ◽  
...  

Author(s):  
Jun-Hyung Lim ◽  
Sang Hwan Nam ◽  
Jongwoo Kim ◽  
Nam Hoon Kim ◽  
Gun-Soo Park ◽  
...  

Abstract In this study, a three-stage bioaerosol sampler with a sampling flow rate of 170 L/min was designed and fabricated for sampling the bioaerosols released during human breathing and coughing, and its performance was evaluated. The sampler was constructed using a cyclone separator with a cutoff size of 2.5 µm as a preseparator, a multi-nozzle virtual impactor with a cutoff size of 0.34 µm as an aerosol concentrator, and a BioSampler, which is a commercial product, for collecting bioaerosols in a collection fluid. The collection efficiency of the sampler was evaluated through simulations and experiments. Only particles with sizes of 0.1-4 µm were selectively collected in the collection fluid. Bacteriophage bioaerosols were sampled using the developed sampler and ACD-200 Bobcat sampler, which is a commercial product. The amounts of collected bacteriophages were compared using the polymerase chain reaction (PCR) technique. The sampling performance of the developed sampler was similar to that of the ACD-200 Bobcat sampler. Moreover, the developed sampler showed its ability to sample bioaerosols of a specific size-range and collect them directly in a collection fluid for the PCR analysis. Therefore, the developed sampler is expected to be useful for indoor environmental monitoring by effectively sampling the bioaerosols released indoors during human breathing and coughing.


Urban History ◽  
1983 ◽  
Vol 10 ◽  
pp. 29-38 ◽  
Author(s):  
R. J. Morris

The poll books produced before the Ballot Act of 1872 are a major source for political and social history. Those which have an occupational title for most or all entries have been increasingly used since Vincent's pioneering work. Others have been linked to other sources so that voting can be related to occupation. This is either time-consuming or expensive and often both. The alternative is a very selective sampling tactic guided by the directories. The use of occupational titles has been criticized because of the lack of social homogeneity within the groups designated by such titles. This is slightly unfair but a relevant warning against using such titles to do more analytical work than the meaning of the titles justifies. Those who want a more precise measure of status must link with the rate books and the census manuscripts.


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