Inter-laboratory comparisons of hexenuronic acid measurements in kraft eucalyptus pulps using a UV-Vis spectroscopic method

TAPPI Journal ◽  
2014 ◽  
Vol 13 (1) ◽  
pp. 57-61 ◽  
Author(s):  
J.Y. ZHU ◽  
H.F. ZHOU ◽  
X.S. CHAI ◽  
DONNA JOHANNES ◽  
RICHARD POPE ◽  
...  
Keyword(s):  
Acid Content ◽  
Spectroscopic Method ◽  
The Other ◽  
Kraft Pulps ◽  
Chemical Pulp ◽  
Three Samples ◽  
Hexenuronic Acid ◽  
Replicate Measurements ◽  
The Comparative Study ◽  
Measurement Repeatability

An inter-laboratory comparison of a UV-Vis spectroscopic method (TAPPI T 282 om-13 “Hexeneuronic acid content of chemical pulp”) for hexeneuronic acid measurements was conducted using three eucalyptus kraft pulps. The pulp samples were produced in a laboratory at kappa numbers of approximately 14, 20, and 35. The hexeneuronic acid contents of the three pulps were approximately 55–65 μmol/g, or with a variation of approximately 15%. Five laboratories from four different countries participated in this round-robin study as part of the evaluation of the TAPPI provisional method for upgrading to a TAPPI standard method. The comparative study showed that the orders of hexeneuronic acid content from low to high among the three pulp samples produced by four laboratories were in agreement. Replicate measurements were not conducted at the laboratory that produced an inconsistent order of hexeneuronic acid among the three pulp samples compared with the other four laboratories. The differences in hexeneuronic acid contents from different laboratories were systematic and consistent; that is, some laboratories consistently produced high values of hexeneuronic acid for all three samples. The comparative data of three pulp samples concluded that the measurement repeatability (within a laboratory) was less than 3% and reproducibility (among laboratories) was less than 16%.

Voltammetric analysis of the bleachability of softwood kraft pulps

Holzforschung ◽  
2004 ◽  
Vol 58 (6) ◽  
pp. 581-587 ◽  
Author(s):  
Robert Bourbonnais ◽  
Loredana Valeanu ◽  
Michael G. Paice
Keyword(s):  
Chlorine Dioxide ◽  
Acid Content ◽  
Black Spruce ◽  
Kappa Number ◽  
Western Hemlock ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Redox Mediators ◽  
Voltammetric Analysis ◽  
Hexenuronic Acid

Abstract Kraft and oxygen delignified pulps with various kappa numbers were prepared from black spruce and western hemlock chips. The bleachability (ratio of kappa number decrease to chlorine dioxide applied) of the different pulps at the same kappa number varied with both wood furnish and delignification process. Thus, unbleached kappa number alone is not a reliable indicator of bleachability for these pulps. This may be due in part to the variable hexenuronic acid content of the pulps; those with higher ratio of hexenuronic acid content to kappa number (HexA/kappa) are harder to bleach. Voltammetric analysis of the same kraft pulps in the presence of redox mediators was found to measure both the content and reactivity of residual lignin. Peak current ratios of redox mediators correlated with pulp bleachability for all pulps. These ratios may therefore provide a more accurate prediction of bleachability than unbleached kappa number.

scholarly journals Catalytic Conversion of n-C7 Asphaltenes and Resins II into Hydrogen Using CeO2-Based Nanocatalysts

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1301
Author(s):  
Oscar E. Medina ◽  
Jaime Gallego ◽  
Sócrates Acevedo ◽  
Masoud Riazi ◽  
Raúl Ocampo-Pérez ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Low Temperatures ◽  
Gaseous Mixture ◽  
H2 Production ◽  
The Other ◽  
Hydrogen Release ◽  
Catalytic Gasification ◽  
Three Samples ◽  
Main Decomposition ◽  
Catalytic Capacity

This study focuses on evaluating the volumetric hydrogen content in the gaseous mixture released from the steam catalytic gasification of n-C7 asphaltenes and resins II at low temperatures (<230 °C). For this purpose, four nanocatalysts were selected: CeO2, CeO2 functionalized with Ni-Pd, Fe-Pd, and Co-Pd. The catalytic capacity was measured by non-isothermal (from 100 to 600 °C) and isothermal (220 °C) thermogravimetric analyses. The samples show the main decomposition peak between 200 and 230 °C for bi-elemental nanocatalysts and 300 °C for the CeO2 support, leading to reductions up to 50% in comparison with the samples in the absence of nanoparticles. At 220 °C, the conversion of both fractions increases in the order CeO2 < Fe-Pd < Co-Pd < Ni-Pd. Hydrogen release was quantified for the isothermal tests. The hydrogen production agrees with each material’s catalytic activity for decomposing both fractions at the evaluated conditions. CeNi1Pd1 showed the highest performance among the other three samples and led to the highest hydrogen production in the effluent gas with values of ~44 vol%. When the samples were heated at higher temperatures (i.e., 230 °C), H2 production increased up to 55 vol% during catalyzed n-C7 asphaltene and resin conversion, indicating an increase of up to 70% in comparison with the non-catalyzed systems at the same temperature conditions.

Formation of contracts for the international sale of goods under Korean law and the CISG

2017 ◽  
Vol 21 (3) ◽  
pp. 208-223
Author(s):  
Byung Mun Lee
Keyword(s):  
Comparative Study ◽  
Design Methodology ◽  
Case Law ◽  
The Other ◽  
Basic Question ◽  
Content Type ◽  
International Sale Of Goods ◽  
The Comparative Study ◽  
International Sales ◽  
Insight Into

Purpose The purpose of this paper is to describe and analyze the rules on the formation of contracts under Korean law and the Contracts for the International Sale of Goods (CISG) in a comparative way and introduce the relevant proposed rules under the Amendment Draft of the Korean Civil Code (KCC). In addition, it attempts to compare and evaluate them in light of the discipline of comparative law. Design/methodology/approach In order to achieve the purposes of the study, it executes a comparative study of the rules as to the formation of contracts of the CISG, Korean law and the Amendment Draft of the KCC. The basic question for this comparative study is placed on whether a solution from one jurisdiction is more logical than the others and to what extent each jurisdiction has responded to protect the reasonable expectations of the parties in the rules as to the formation of contracts. Findings The comparative study finds that most of the rules under the CISG are quite plausible and logical and they are more or less well reflected in the proposals advanced by the KCC amendment committee. On the other hand, the other rules under the CISG which have brought criticisms in terms of their complexity and inconsistent case law invite us their revision or consistent interpretation. The drawbacks of the CISG have also been well responded in the Amendment Draft of the KCC. Nevertheless, it is quite unfortunate that the Amendment Draft of the KCC still has a rule that regards any purported performance with non-material alteration of the terms of an offer as an acceptance. Originality/value This study may provide legal and practical advice to both the seller and the buyer when they enter into a contract for international sales of goods. In addition, it may render us an insight into newly developed or developing rules in this area and show us how they interact with each other. Furthermore, it may be particularly useful in Korea where there is an ongoing discussion for revision of the KCC.

Filtration by superficial and deep glomeruli of normovolemic and volume-depleted rats

1986 ◽  
Vol 250 (1) ◽  
pp. F86-F91
Author(s):  
R. V. Pinnick ◽  
V. J. Savin
Keyword(s):  
Basement Membrane ◽  
Maximum Rate ◽  
Rate Of Change ◽  
The Other ◽  
Membrane Area ◽  
Morphometric Analyses ◽  
Three Samples ◽  
Glomerular Size ◽  
Glomerular Ultrafiltration

We measured glomerular ultrafiltration coefficient (Kf) of isolated superficial (S) and deep (D) glomeruli of normovolemic and volume-depleted rats. Filtration was induced in vitro, and Kf was calculated from the maximum rate of change in glomerular size. Basement membrane area (A) for each glomerulus was estimated from morphometric analyses, and glomerular capillary hydraulic conductivity (Lp) was calculated by the formula Lp = Kf/A. Kf of S and D glomeruli of normovolemic rats were 2.98 +/- 0.98 and 4.25 +/- 0.07 nl . min-1 . mmHg-1, respectively. In hypovolemic rats, Kf of S glomeruli fell by approximately 50% to 1.52 +/- 0.14 nl . min-1 . mmHg-1 (P less than 0.001), whereas Kf of D glomeruli remained unchanged at 4.28 +/- 0.10 nl . min-1 . mmHg-1. Lp, calculated using the peripheral capillary area, averaged 1.98 +/- 0.09 and 1.98 +/- 0.06 microliter . min-1 . mmHg-1 . cm-2 in S and D glomeruli of normovolemic rats and 1.89 +/- 0.11 microliter . min-1 . mmHg-1 . cm-2 in D glomeruli of hypovolemic rats. Lp of S glomeruli of volume-depleted rats (0.90 +/- 0.03 microliter . min-1 . mmHg-1 . cm-2) was lower than in any of the other three samples. Mild hypovolemia causes the Kf of S glomeruli to decline, whereas Kf of D glomeruli remains constant. The decrease in Kf occurs without an alteration in capillary area and is most likely due to a decrease in Lp.

Reactions of aromatic structures in brightness reversion of fully-bleached eucalyptus kraft pulps

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Anna-Stiina Jääskeläinen ◽  
Katri Toikka ◽  
Anni Lähdetie ◽  
Tiina Liitiä ◽  
Tapani Vuorinen
Keyword(s):  
Resonance Raman ◽  
Kraft Pulps ◽  
Brightness Reversion ◽  
Vis Spectroscopy ◽  
Uv Resonance Raman ◽  
Hexenuronic Acid

Abstract The role of aromatic structures in brightness reversion of fully bleached pulps was studied by UV resonance Raman (UVRR) and reflectance UV-Vis spectroscopy. The results clearly showed that ageing increased the aromatic band at approximately 1600 cm-1 in the UVRR spectra and the lignin band at approximately 280 nm in the UV-Vis spectra. This increase was probably due to increased conjugation of lignin and it was observed for all pulps regardless of the bleaching sequence. In addition to these lignin reactions, other unsaturated structures, such as hexenuronic acid groups, reacted during ageing.

Writing

1993 ◽  
Author(s):  
Mark Selikowitz
Keyword(s):  
High School ◽  
Standardized Tests ◽  
Comprehensive Assessment ◽  
The Other ◽  
Manual Task ◽  
Three Samples ◽  
Writing Skill ◽  
Form Part ◽  
Significant Impairment ◽  
Reading And Spelling

When David was 12 years old it became apparent that he was having significant difficulty writing. He struggled on, but his writing did not improve and he was regularly having his work returned by teachers because it was illegible. If he tried to write painstakingly slowly he could produce work that was barely legible, but there was not enough time to do this during examinations. David was very intelligent, an avid reader, an excellent debater, and good at sports. He was well coordinated in every manual task except writing, and was physically healthy. No cause for his difficulty could be found. At high school and university, he was given permission to type his examination papers and obtained excellent results. He is now a professor of law. He still cannot write legibly, but has had many papers and a number of books published. He uses a combination of dictation and typing instead of writing. This chapter deals with the mechanics of handwriting, that is, the formation of letters and their arrangement on the page. In contrast with disorders of reading and spelling, such difficulties have received little attention. This is partly because writing is a skill that cannot be easily evaluated by standardized tests, and partly because significant impairment of writing skill seems to be relatively uncommon. Unfortunately, this lack of knowledge means that children with specific writing difficulty are often misunderstood and maligned. Assessment of writing should form part of a comprehensive assessment, as described in Chapter 2. It is impossible to score a sample of writing in a precise way. In practice, samples of writing are usually evaluated by an experienced tester. Three samples of writing are obtained: a passage of free composition on a particular topic, a piece of dictation, and a copy of some printed material. In the case of the free composition, the child is usually given a limited amount of time, such as five minutes. In the other two tests, he is timed to see how long he takes.

Über die quantitative Verteilung der Ascorbinsäure innerhalb der Pflanzenzelle

1964 ◽  
Vol 19 (12) ◽  
pp. 1146-1149 ◽  
Author(s):  
Wolfgang Franke ◽  
Ulrich Heber
Keyword(s):  
Ascorbic Acid ◽  
Acid Content ◽  
Cell Walls ◽  
Direct Evidence ◽  
Ascorbic Acid Content ◽  
The Other ◽  
Leaf Cell ◽  
Unequal Distribution ◽  
Freeze Dried ◽  
High Figure

Leaves, which had been killed in liquid air, were freeze dried and then fractionated by a nonaqueous method. Two fractions were obtained, one consisting of chloroplasts and the other of cytoplasm, vacuolar constituents, cell walls and residual chloroplasts. Calculation of the intracellular distribution of ascorbic acid based on the analysis of the two fractions revealed that 40 to 50% of the total ascorbic acid content of the cells is located within the chloroplasts. Since chloroplasts occupy less than 10% of the total volume of the cells, this high figure is direct evidence of an unequal distribution of ascorbic acid within the leaf cell.

scholarly journals Chlorogenic acid content in potato tubers with colored flesh as affected by a genotype, location and long-term storage

2019 ◽  
Vol 65 (No. 7) ◽  
pp. 355-360
Author(s):  
Matyáš Orsák ◽  
Karel Hamouz ◽  
Jaromír Lachman ◽  
Pavel Kasal
Keyword(s):  
Chlorogenic Acid ◽  
Acid Content ◽  
Field Experiments ◽  
The Other ◽  
Potato Tubers ◽  
Flesh Color ◽  
Long Term Storage ◽  
And Storage ◽  
Term Storage

In three-year field experiments, the effect of genotype, flesh color, site conditions and storage on chlorogenic acid content (CAC) in tubers of potato cultivars with purple or red flesh was compared to yellow-fleshed cv. Agria. The results confirmed the significant effect of genotype on CAC. The highest CAC was characteristic on a three-year mean for the purple-fleshed cv. Vitelotte (769.5 mg/kg fresh weight (FW)), i.e. 1.19−2.6 times higher than in the other cultivars. In regard to the effect of flesh color, significantly higher mean CAC levels have been shown for the red-fleshed (2.8 times) and purple-fleshed (3.16 times) cultivars in comparison with cv. Agria (148 mg/kg FW). At the Uhříněves location with a warmer climate and frequent dry periods as compared to the second Valečov location, a higher CAC (1.18 times) was found. Cold storage (4°C, 6 months) resulted in a significant CAC increase varying from 33.2% in the Blaue St. Galler cultivar to 210.6% in the Vitelotte cultivar among all eight evaluated color-fleshed cultivars. On the other hand, the effect of storage on CAC was not evident in the yellow-fleshed Agria cultivar (inconclusive difference against CAC after harvest).

scholarly journals A Study of the Micropore Structure of Carbonized Rayon Yarn by Nitrogen Adsorption and Nonane Pre-Adsorption

1985 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
J. N. Bohra ◽  
K. S. W. Sing
Keyword(s):  
External Surface ◽  
Nitrogen Adsorption ◽  
The Other ◽  
Adsorption Method ◽  
Micropore Structure ◽  
Surface Areas ◽  
Three Samples ◽  
Two Samples ◽  
Before And After ◽  
Gain Access

Adsorption isotherms of nitrogen have been determined at 77 K on three samples of carbonized rayon yarn, both before and after the pre-adsorption of n-nonane. In their original state the three samples were all highly microporous. Application of the αs-method of isotherm analysis reveals that their micropore volumes were 0·17–0·19 cm3g−1 and their external surface areas 20–27 m2g−1 (the corresponding BET areas being 427–483 m2g−1). Nonane pre-adsorption resulted in blockage of the entire micropore structure only in the case of one sample: micropore volumes ∼0·1 cm3g−1 were still available for nitrogen adsorption in the other two samples. It appears that nitrogen molecules were able to gain access to some parts of these micropore structures through wider pore entrances which were not completely blocked by the pre-adsorbed nonane. The work has shown that the nonane pre-adsorption method requires further investigation before it can be used with confidence for the assessment of microporosity.

Preferential Marriage: Correlation of the Various Modes among the Bantu Tribes of the Union of South Africa

Africa ◽  
1928 ◽  
Vol 1 (4) ◽  
pp. 413-428 ◽  
Author(s):  
Werner Eiselen
Keyword(s):  
South Africa ◽  
Comparative Study ◽  
Social Organization ◽  
Strong Evidence ◽  
The Other ◽  
Cousin Marriage ◽  
Independent Origin ◽  
The World ◽  
The Comparative Study

The several forms of preferential mating, such as cross-cousin marriage, sororate and levirate, are well known and have been reported from all the ethnographic provinces of the world. Lately Lowie and Rivers have devoted special chapters in their books on social organization to the comparative study of these important institutions. Lowie has pointed out that there is strong evidence for the correlation of sororate and levirate. The later publication of Rivers hardly serves to make these matters any clearer than Lowie's work. Although the latter scholar, with Tylor and others, recognized the close connexion existing between sororate and levirate, the evidence at his disposal did not allow him to arrive at a similar conclusion with regard to the other forms of preferential marriage. Accordingly he had to treat them, for the time being, as institutions of independent origin.

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