165,808 research outputs found
Orthogonal least squares methods and their application to non-linear system identification
No full textIdentification algorithms based on the well-known linear least squares methods ofgaussian elimination, Cholesky decomposition, classical Gram-Schmidt, modifiedGram-Schmidt, Householder transformation, Givens method, and singular valuedecomposition are reviewed. The classical Gram-Schmidt, modified Gram-Schmidt,and Householder transformation algorithms are then extended to combinestructure determination, or which terms to include in the model, and parameterestimation in a very simple and efficient manner for a class of multivariablediscrete-time non-linear stochastic systems which are linear in the parameters
O pułapce „skojarzeniowej” w humanistyce. (Na marginesie uroszczenia S. Gałkowskiego w jego próbie „logicznej” wykładni Znanieckiego)
Full text linkAutor polemiki we wstępie wskazuje na zjawisko "reductio ad absurdum" koncepcji Znanieckiego w wykładni adresata jego krytyki. Dalej jest zarysowana ogólna perspektywa sprzeciwu wobec podejścia Stanisława Gałkowskiego. Przedstawiono także krytycyzm i pochwały wobec Znanieckiego ze strony autora polemiki. W tekście wskazuje się na pułapkę czytania epistemicznego jako etyczne nadużycie logiki. Wreszcie, zamiast zakończenia, mówi się o traktowaniu tradycji myśli humanistycznej i uczula na błędy interpretacyjne popełnione przez krytykowanego autora. Główny błąd polega na skojarzeniach czytelnika blokujących mu głębszy dostęp do znaczenia czytanej koncepcji.In his introduction the author of this polemic indicates the phenomenon of "reductio ad absurdum" of Znaniecki's conception in the exegesis of the addressee of this criticism. Next there is an outline sketched concerning the general perspective of disagreement against the approach by S. Gałkowski. There is also outlined criticism and appraisal towards Znaniecki by the author of this polemics. The text illustrates the trap of an epistemic reading as an ethical abuse of logics. Finally instead of a conclusion one is discussing the ways of treatement of the tradition of humanistic reflection and it warns against interpretative errors committed by the criticised author. The basic error is perceived as the result of domination of application of harmful associations of the leader blocking the way to deeper sense of the conception
Sebastes ensifer Chen 1971
No full textSebastes ensifer Chen, 1971. Swordspine Rockfish. To 30.5 cm (12 in) TL (Miller and Lea 1972). Oregon (43°56’N) (NWFSC-FRAM) to Banco Ranger (28°25’N, 115°32’W), central Baja California (Chen 1971). Benthic; depth: 50–433 m (164–1,420 ft) (min.: M.L., unpubl. data; max.: Miller and Lea 1972).Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 108, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/557800
INNOVATIVE PILLAR[6]ARENE-BASED STATIONARY PHASES FOR HIGH-RESOLUTION GAS CHROMATOGRAPHIC ANALYSES
No full textIn this work, the synthesis, fabrication, and characterization of new stationary phases based on pillar[6]arene derivative modified by long alkyl chains (P6A-C10) for high-resolution gas chromatographic (GC) analyses are reported. Pillar[n]arenes are a new class of macrocyclic hosts that can accommodate specific guests due to their highly symmetrical and rigid pillar architectures with π-electron rich cavities. Quantum chemistry calculations have been performed, showing a difference in non-covalent interactions with the P6A-C10 pillar framework, which leads to specific selectivity for aromatic compounds. The GC columns prepared with these innovative stationary phases exhibited a medium polarity, and good reproducibility for run-to-run, day-to-day, and column-to-column analyses [1], demonstrating great potential as new stationary phases in separation science. Furthermore, peculiar advantages are achieved if compared with the commercial HP-5, HP-35, DB-17, and PEG-20M columns, showing unmatched resolving capabilities toward chloroaniline, bromoaniline, iodoaniline, toluidine, and xylene isomers [2].
References:
1. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Hu, S., Liu, X., Nardiello, D., & Quinto, M., ACS Appl. Mater. Interfaces 14 (2022) 56132−56142.
2. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Chen, H., Qi, Y., Chen, H., Liu, X., Nardiello, D., & Quinto, M., Anal. Chim. Acta 1251 (2023) 340979
ISOMER SEPARATIONS BY INNOVATIVE GAS CHROMATOGRAPHY STATIONARY PHASES
No full textThe chromatographic separation of aromatic amines and xylenes isomers represents a big issue in chemical and petroleum industries, owing to their high similarity in terms of molecular sizes, polarity, and boiling points: as a result, commercial columns very often do not allow their complete peak separation. For this reason, several typologies of materials with different structures and properties have been developed and proposed as gas chromatography stationary phases in recent years. Macrocycles and ionic liquid-based chain-typed copolymers have emerged, due to their special chromatographic selectivity and separation mechanisms, resulting from their three-dimensional structures and outstanding thermal stability. Very recently, innovative stationary phases based on functionalized calixarene-polyethylene glycol (C4A-mPEG) [1], and amphiphilic triblock copolymer bonded with benzimidazolium ionic liquid (TCP-Bim) [2] were designed, characterized, and used for GC separations of aromatic isomers. The separation features of the C4A-mPEG stationary phase, resulting from multiple molecular recognition processes with analytes, including π-π, H-bonding, dipole-dipole, and van der Waals interactions, allowed to obtain high-resolution performances for a wide range of compounds and their isomers, especially benzaldehydes, phenols, and anilines. Moreover, compared with 4-tertbutyl calix[4]arene (C4A) and polyethylene glycol (PEG) stationary phases, a higher resolving capability was also observed for the separation of toluidine and xylidine isomers. The separation capabilities of the TCP-Bim columns are attributable to different analyte-stationary phase interaction mechanisms, arising from the particular TCP-Bim structure that combines ionic liquid and copolymer peculiarities, showing stronger retention towards aromatic compounds. The high-resolution capabilities of the TCP-Bim column were also tested with different aliphatic cis-/trans-isomers; the excellent separation performances for analytes with very similar properties demonstrated the good potential of these innovative materials as new classes of stationary phases for high-resolution GC separations.
References:
1. Chen, R., Cai, Z., Li, W., Huang, Q., Nardiello, D., Quinto, M., Liu, X., Hu, S., & Sun, T., Chem. Biodiversity 19 (2022) e202200829.
2. Huang, Q., Cai, Z., Chen, R., Zhang, W., Nardiello, D., Quinto, M., Liu, X., Hu, S., & Sun, T., Microchemical Journal 183 (2022) 108084
Simultaneous space charge and conduction current measurements in solid dielectrics under high dc electric field
No full textThe importance of space charge in solid dielectrics has been recognized for many years and various attempts have been made to map the distribution and assess its influence on the electrical performance of solid dielectrics. Significant development in non-destructive measurement techniques emerged two decades ago. Crosslinked polyethylene (XLPE) has been used for ac power cable insulation up to 500 kV for many years. There is a tendency to use XLPE for dc power cable. However, the easy formation of space charge under dc electric field within XLPE is a major concern for such an application. Space charge in insulation can distort electric field distribution, causing electric field increase in one region and reduction in another. The electric field enhancement could lead to degradation and result in premature failure. Electrical treeing in solid dielectrics is a typical example of local field enhancement due to space charge accumulation. In this report several popular non-destructive techniques are briefly reviewed. This is followed by detailed description of a modified pulsed electroacoustic (PEA) technique that allows simultaneous measurement of space charge and conduction current in a solid dielectric subjected to high dc electric fields. Finally, we report the relationship between space charge dynamics and electrical conduction current in XLPE using the modified PEA system. The effect of electrode material on both charge dynamics and current has been investigated using semiconducting material and aluminium. It has been found charge dynamics in the material depend on electrode configuration. More importantly, it has been noticed that the so called space charge limited transient current peaks are closely related to the meetings of negative and positive charge front in the bulk of the sample
Sebastes notius Chen 1971
No full textSebastes notius Chen, 1971. Guadalupe Rockfish or Southern Rockfish. To 21.9 cm (8.6 in) SL (Chen 1971). This species has been collected at two sites: Isla Guadalupe (Chen 1971), central Baja California and in the vicinity of Banco del Tio Sam (Uncle Sam Bank) (25°35’N), southern Baja California (Rocha-Olivares 1998). Benthic; depth: 165–250 m (541–820 ft) (Chen 1971).Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 110, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/557800
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