Theoretical analysis of ultraviolet spectroscopic studies on the feathering of cream in coffee

1989 ◽  
Vol 56 (5) ◽  
pp. 749-754 ◽  
Author(s):  
David A. Pink ◽  
Lucie Hamboyan ◽  
Helen Aboud
Keyword(s):  
Theoretical Analysis ◽  
Chlorogenic Acid ◽  
Linear Combination ◽  
Spectroscopic Studies ◽  
The Other ◽  
Ultraviolet Spectra ◽  
Spectral Bands

SummaryUltraviolet spectra of solutions of instant and filter coffees have been analysed as a linear combination of component Gaussian bands. We show that the ratio, R′, of two of these bands, one at 329 nm due almost entirely to chlorogenic acid, and the other at 272 nm due to a coffee component not appearing in the chlorogenic acid spectrum, is analogous to the ratio R (Hamboyan et al. 1989). The use of R which is easier to measure than R′ has therefore been justified on physical grounds, based on the existence of component spectral bands. Filter coffees appeared to exhibit behaviour similar to that of instant coffees.

Ultraviolet spectroscopic studies on the feathering of cream in instant coffee

1989 ◽  
Vol 56 (5) ◽  
pp. 741-748 ◽  
Author(s):  
Lucie Hamboyan ◽  
David A. Pink* ◽  
Dieter Klapstein ◽  
Lynn MacDonald ◽  
Helen Aboud
Keyword(s):  
Chlorogenic Acid ◽  
Acid Content ◽  
Room Temperature ◽  
Spectroscopic Studies ◽  
Minimum Amount ◽  
Instant Coffee ◽  
Ultraviolet Spectra

SummaryThe extent of cream feathering was observed in samples of six brands of instant coffee at 80 °C and classified on a scale of 0 (non-existent)–3 + (very severe). The hypothesis that it is caused by the amount of chlorogenic acid in the samples was tested. Ultraviolet spectra were recorded between 230 and 486 nm, and the amount of chlorogenic acid was measured from the absorbance at 340 nm. It was found that: (i) u.v. spectra of a given brand of coffee prepared at different concentrations could all be superimposed when concentration and dilution were taken into account, and the spectrum did not change between room temperature and 80 °C; (ii) for a given coffee a minimum amount of chlorogenic acid was needed to cause feathering, but that this amount differed by up to a factor of 10 depending upon the coffee; (iii) only two fundamental shapes of spectra were observed and coffees could be classified by a ratio, R, which lay between two ranges: 0·82 < R < 0·90 or 1·10 < R < 1·27; (iv) a knowledge of the chlorogenic acid content of a sample and the value of R appropriate to that coffee could be used to predict the occurrence of feathering.

scholarly journals Voigt Transform and Umbral Image

2020 ◽  
Vol 25 (3) ◽  
pp. 49
Author(s):  
Silvia Licciardi ◽  
Rosa Maria Pidatella ◽  
Marcello Artioli ◽  
Giuseppe Dattoli
Keyword(s):  
Spectroscopic Studies ◽  
Higher Order ◽  
Point Of View ◽  
The Other ◽  
Pivotal Role ◽  
Umbral Calculus ◽  
Laguerre Functions ◽  
Hermite And Laguerre Functions ◽  
Higher Order Functions ◽  
Voigt Function

In this paper, we show that the use of methods of an operational nature, such as umbral calculus, allows achieving a double target: on one side, the study of the Voigt function, which plays a pivotal role in spectroscopic studies and in other applications, according to a new point of view, and on the other, the introduction of a Voigt transform and its possible use. Furthermore, by the same method, we point out that the Hermite and Laguerre functions, extension of the corresponding polynomials to negative and/or real indices, can be expressed through a definition in a straightforward and unified fashion. It is illustrated how the techniques that we are going to suggest provide an easy derivation of the relevant properties along with generalizations to higher order functions.

scholarly journals On the Recurrence Properties of Narayana’s Cows Sequence

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 149
Author(s):  
Xin Lin
Keyword(s):  
Linear Combination ◽  
The Other ◽  
Other Hand ◽  
Computation Formula ◽  
The One

In this paper, we consider the recurrence properties of two generalized forms of Narayana’s cows sequence. On the one hand, we study Narayana’s cows sequence at negative indices and express it as the linear combination of the sequence at positive indices. On the other hand, we study the convolved Narayana number and obtain a computation formula for it.

THEORETICAL ANALYSIS AND EXPERIMENT OF A NOVEL DEP CHIP WITH 3-D SILICON ELECTRODES

2005 ◽  
Vol 15 (02) ◽  
pp. 231-236 ◽  
Author(s):  
LIMING YU ◽  
FRANCIS E. H. TAY ◽  
GUOLIN XU ◽  
CIPRIAN ILIESCU ◽  
MARIOARA AVRAM
Keyword(s):  
Theoretical Analysis ◽  
Applied Voltage ◽  
Microfluidic Channel ◽  
The Other ◽  
Yeast Cells ◽  
Applied Potential ◽  
Dielectrophoretic Force ◽  
Joule Effect ◽  
Doped Silicon ◽  
Planar Electrodes

This paper presents a novel dielectrophoresis (DEP) device where the DEP electrodes define the channel walls. This is achieved by fabricating microfluidic channel walls from highly doped silicon so that they can also function as DEP electrodes. Compared with planar electrodes, this device increases the exhibited dielectrophoretic force on the particle, therefore decreases the applied potential and reduces the heating of the solution. A DEP device with triangle electrodes has been designed and fabricated. Compared with the other two configurations, semi-circular and square, triangle electrode presents an increased force, which can decrease the applied voltage and reduce the Joule effect. Yeast cells have been used to for testing the performance of the device.

A modified Runge-Kutta method

SIMULATION ◽  
1968 ◽  
Vol 10 (5) ◽  
pp. 221-223 ◽  
Author(s):  
A.S. Chai
Keyword(s):  
Error Estimate ◽  
Linear Combination ◽  
Experimental Results ◽  
The Other ◽  
New Method ◽  
Kutta Method ◽  
Starting Values ◽  
Runge Kutta Method ◽  
Runge Kutta ◽  
A Minor

It is possible to replace k2 in a 4th-order Runge-Kutta for mula (also Nth-order 3 ≤ N ≤ 5) by a linear combination of k1 and the ki's in the last step, using the same procedure for computing the other ki's and y as in the standard R-K method. The advantages of the new method are: It re quires one less derivative evaluation, provides an error estimate at each step, gives more accurate results, and needs a minor change to switch to the RK to obtain the starting values. Experimental results are shown in verification of the for mula.

Finally, Our Own Brown! (?)

2012 ◽  
Vol 45 (2) ◽  
pp. 267-289 ◽  
Author(s):  
Yifat Bitton
Keyword(s):  
African American ◽  
Theoretical Analysis ◽  
Supreme Court Decision ◽  
The Other ◽  
Court Decision ◽  
High Court ◽  
Court Of Justice ◽  
Us Supreme Court ◽  
Distinctive Group ◽  
Contextual Reality

The decision in Noar Kahalacha, an anti-segregation in education case that was recently delivered by the Israeli High Court of Justice, has been ‘naturally’ celebrated as the ‘Israeli Brown’. But is it? This article points to the differences between the monumental US Supreme Court decision of Brown and the Israeli Brown-equivalent – Noar Kahalacha. It contends that the two cases bear differences that stem from the divergent patterns of discrimination they represent, and that they reflect these differences squarely. The discrimination patterns reflected by the cases differ by virtue of traits that are traditionally overlooked in antidiscrimination theoretical analysis. Comparing the two cases, therefore, allows us an opportunity to revisit the notion of discrimination and its antidote, antidiscrimination. Drawing on the dichotomous concepts of de jure/de facto discrimination and difference/sameness discrimination, the article shows how these dual theoretical notions are determinative in shaping the distinctiveness of each of these cases. While the African American victims in Brown were easily recognised as a distinctive group suffering from de jure discrimination, the Mizrahi victims in Noar Kahalacha – who suffer from de facto discrimination within a Jewish hegemonic society – lacked such clear recognition. Accordingly, the discrimination narrative that Noar Kahalacha provides is very incomplete and carries only limited potential for effective application in future struggles to eliminate discriminatory practices against Mizrahis in Israel. Brown, on the other hand, carries a converse trait. Though criticised, Brown, nevertheless, strongly signifies the recognition by White America of its overarching discriminatory practices, and implies a genuine dedication to break from it. This understanding further illuminates the limitations embedded in the possibility of ‘importing’ highly contextual antidiscrimination jurisprudence from abroad into our system's highly contextual reality of discrimination.

Benessere tra differenze e disuguaglianze di genere in salute

2012 ◽  
pp. 95-113
Author(s):  
Rita Biancheri
Keyword(s):  
Theoretical Analysis ◽  
Empirical Research ◽  
Personal History ◽  
The Other ◽  
Sex And Gender ◽  
Welfare Systems ◽  
Life Context ◽  
And Gender ◽  
The One ◽  
Sick Individual

Up to now, in the traditional biomedical paradigm the terms "sex" and "gender" have either been used synonymously and the insertion of gender among the determining elements of conditions of wellbeing/disease has been difficult, and obstructed by disciplinary rigidities that retarded the acceptance of an approach which had already been largely found to be valid in other areas of research. The effected simplification demonstrated its limitations in describing the theme of health; but if, on the one hand, there has been a growing awareness of a subject which can in no way be considered "neutral", on the other hand there continues to be insufficient attention, both in theoretical analysis and in empirical research, given to female differences. The article is intended to support that the sick individual is a person, with his/her genetic heritage, his/her own cultural acquisitions and personal history, and own surrounding life context; but these and similar factors have not traditionally been taken into consideration by official medicine and welfare systems, despite a hoped-for socio-health integration.

Comparative Spectroscopic Studies on Luminescence Performance of Er3+ Doped Tellurite Glass Embedded with Different Nanoparticles (Ag Co and Fe) at 0.55 μm Emission

2021 ◽  
Vol 317 ◽  
pp. 81-86
Author(s):  
Syariffah Nurathirah Syed Yaacob ◽  
Md. Rahim Sahar ◽  
Faizani Mohd Noor ◽  
Nur Liyana Amiar Rodin ◽  
Siti Khadijah Mohd Zain ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Ground State ◽  
Tellurite Glass ◽  
Spectroscopic Studies ◽  
The Other ◽  
X Ray Diffraction ◽  
Melt Quenching ◽  
X Ray ◽  
Doped Glass ◽  
Luminescence Performance

The spectroscopic performance of Er3+ doped glass at 0.55 mm emission contain different nanoparticles NPs have been comparatively evaluated. Glass containing 1.0 mol % of Er3+ doped with different NPs (Ag, Co and Fe ) have been prepared using melt quenching technique. X-ray diffraction analysis reveals the all the prepared samples are amorphous. The UV-Vis absorption spectra of all glasses show several prominent peaks at 525 nm, 660 nm, 801nm, 982 nm and 959 nm due to transition from ground state 4I15/2 to different excited of 2H11/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The emission of Er3+ at 0.55 mm for glass contain Ag NP shows significant enhancement about 3 folds up to 0.6 mol%. On the other hand, the emission of Er3+ at 0.55 mm for glass containing Fe NPs and Co NPs intensely quench probably due to the energy-transfer from Er3+ ion to NPs and magnetic contributions.

scholarly journals Relevance and Standardization of In Vitro Antioxidant Assays: ABTS, DPPH, and Folin–Ciocalteu

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Helena Abramovič ◽  
Blaž Grobin ◽  
Nataša Poklar Ulrih ◽  
Blaž Cigić
Keyword(s):  
Ascorbic Acid ◽  
Chlorogenic Acid ◽  
Gallic Acid ◽  
Caffeic Acid ◽  
Sulfonic Acid ◽  
Epigallocatechin Gallate ◽  
The Other ◽  
Oh Groups ◽  
Standard Compound

Trolox, gallic acid, chlorogenic acid, caffeic acid, catechin, epigallocatechin gallate, and ascorbic acid are antioxidants used as standards for reaction with chromogenic radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH⋅) and 2,2′-azino-bis-3-ethylbenzotiazolin-6-sulfonic acid (ABTS⋅+), and Folin–Ciocalteu (FC) reagent. The number of exchanged electrons has been analyzed as function of method and solvent. A majority of compounds exchange more electrons in FC assay than in ABTS and DPPH assays. In reaction with chromogenic radicals, the largest number of electrons was exchanged in buffer (pH 7.4) and the lowest reactivity was in methanol (DPPH) and water (ABTS). At physiological pH, the number of exchanged electrons of polyphenols exceeded the number of OH groups, pointing to the important contribution of partially oxidized antioxidants, formed in the course of reaction, to the antioxidant potential. For Trolox, small impact on the number of exchanged electrons was observed, confirming that it is more suitable as a standard compound than the other antioxidants.

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