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Acid Number (acid + number)
Kinds of Acid Number Selected AbstractsEffects of additives on oxidation characteristics of palm oil-based trimethylolpropane ester in hydraulics applicationsEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 4 2009Nor Halaliza Alias Abstract Hydraulic fluids represent one of the most important groups of industrial lubricants. Increasing attention to environmental issues drives the lubricant industry to choose vegetable-based hydraulic fluids which are biodegradable as compared to mineral-based fluids. However, the lubricating properties of vegetable oil, such as poor oxidative stability and high pour point, have hindered their use. In this study, trimethylolpropane ester, which was derived from palm-based methyl ester, was used as the base hydraulic fluid. The purpose of the study was to determine the optimum formulation for palm oil-based synthetic lubricants by using suitable additives that can improve the oxidative stability and viscosity in accordance with the standard regulations for hydraulic fluid applications. The oxidative stability of the oil was evaluated by total acid number (TAN) and viscosity tests. In general, base oil without additive began to degrade after 200,h. The formulated oil, on the other hand, was quite stable even after 800,h of operation. The best formulation was obtained using 1.0% of either additive,A or additive,B. Both TAN and viscosity values were found to increase with increasing heating temperature. Meanwhile, the results have also shown that additive,A performs better than additive,B. After 800,h of exposure, the final TAN value for the formulated oil was only at 0.32 as compared to 4.88,mg KOH/g for the oil without additive. However, the kinematic viscosity of the oil at 40 and 100,°C was almost unchanged as compared to the oil without additive. [source] Effect of egg proteins on the quality and refrigerated storage life of chicken patties made with broiler-spent hen meat and by-products,INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2007A. Kalaikannan Summary The effects of whole egg powder (WEP), dried albumen (DA), dried yolk (DY) at a 1% level and liquid egg (LE) at a 3.7% level on the quality characteristics and refrigerated storage (4 ± 1 °C) stability of chicken patties made with meat and by-products of broiler-spent hens were evaluated. The addition of egg powders significantly enhanced the emulsion stability (ES) and product yield compared with control and LE. There was a marked increase in moisture content and sensory attributes by the addition of egg powders. During the refrigerated storage (4 ± 1 °C), thio-barbituric acid number (TBARS), aerobic plate count (APC) and psychrophilic count increased in all samples. Incorporation of DA and DY significantly reduced the TBARS number and APC during the storage over control. The addition of DA, DY and WEP significantly lowered the psychrophilic counts. Treated and control patties packaged in LDPE (low-density polyethylene) pouches were acceptable for 20 days and 15 days, respectively. [source] Structure investigation of Maltacine C1a, C1b, C2a and C2b,cyclic peptide lactones of the Maltacine complex from Bacillus subtilisJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2005Gunnar Hagelin Abstract A new complex of cyclic peptide lactone antibiotics from Bacillus subtilis, which we named Maltacines, has recently been described. The structure elucidation of four of them is reported in this paper. The amino acid sequences and structures of the peptides were found by MSn of the ring-opened linear peptides, which gave uninterrupted sequences of Bn and Y,n ions. The identities of three unknown residues in the sequences were solved by a combination of derivatisation with phenylisothiocyanate (PITC), high-resolution mass spectrometry and H/D exchange. The nature and position of the cyclic structure was disclosed by a chemo-selective ring opening with Na18OH and was found to be a lactone formed between a hydroxyl of residue number 4 and the C -terminal amino acid number 12. For verification of the structure of the B2+ ion, peptides with different combinations of P/Q and P/K at the N -terminus were synthesised. The structure of the four peptides were found to be: C1a and C2a: cyclo-4,12(P-Q-Y-Adip-V-E-T-Y-Orn-103-Y-I-OH) and C1b/C2b: cyclo-4,12(P-Q-Y-Adip-V-E-T-Y-K-103-Y-I-OH). Adip = aminodihydroxy pentanoic acid. Copyright © 2005 John Wiley & Sons, Ltd. [source] Structure investigation of Maltacine D1a, D1b and D1c,cyclic peptide lactones of the Maltacine complex from Bacillus subtilisJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 10 2005Gunnar Hagelin Abstract A new complex of cyclic peptide lactone antibiotics from Bacillus subtilis, which we named Maltacines has recently been described. The structure elucidation of three of them is reported in this paper. The amino acid sequences and structures of the peptides were found by MSn of the ring-opened linear peptides that gave uninterrupted sequences of Bn and Y,n ions. The identities of four unknown residues in the sequences were solved by a combination of derivatisation with phenylisothiocyanate (PITC), high-resolution mass spectrometry and H/D exchange. The nature and position of the cyclic structure was disclosed by a chemo-selective ring opening with Na18OH and was found to be a lactone formed between a hydroxyl of residue number 4 and the C -terminal amino acid number 12. For verification of the structure of the B2+ ion, peptides with different combinations of P/Q and P/K at the N -terminus were synthesized. The structures of the four peptides is tentatively suggested to be: D1a: cyclo(4,12)-P-Q-Y-Adip-A-E-T-Y-Orn-HGly-Y-I-OH, D1b: cyclo(4,12)-P-Q-Y-Adip-A-E-T-Y-Orn-S-Y-I-OH and D1c: cyclo(4,12)-P-Q-Y-Adip-A-E-T-Y-K-S-Y-I-OH. Adip = aminodihydroxy pentanoic acid and HGly = hydroxyglycine. Copyright © 2005 John Wiley & Sons, Ltd. [source] The impact of detergent chemistry on TBN retentionLUBRICATION SCIENCE, Issue 3 2000W. van Dam Abstract Historically, the characterisation of fresh and used diesel engine lubricants has been based on a limited number of analytical techniques. One of the most important methods of analysis has been total base number (TBN) measurement. Although TBN measurements are informative, easy, and quick, it can be misleading to base the judgement of an oil's performance solely on one criterion. This paper offers some observations from a field test, showing that some detergent types gave unacceptable performance even though the TBNs were at an acceptable level. It is hypothesised that some detergents do not effectively neutralise all acidic species present in the lubricant, thereby reserving their own base, while in fact the oil may no longer provide sufficient protection against bearing corrosion. This hypothesis is supported by bench and engine test data. It is recommended that, at a minimum, total acid number (TAN) measurements be included in any analysis, and where time and cost permit, wear metals content, oxidation, soot content, and viscosity should also be evaluated. [source] Erosion-corrosion of Q235 and 5Cr1/2Mo steels in oil with naphthenic acid and/or sulfur compound at high temperatureMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 8 2005D. R. Qu Abstract The erosion-corrosion behaviors of Q235 steel and 5Cr1/2Mo steel in oil with naphthenic acid and/or sulfur compound at high temperature were studied in a hot oil loop simulating oil refining environments. The effects of impinging flow rate, incidence angle, and total acid number (TAN), and sulfur content on erosion-corrosion behavior were assessed. The eroded surfaces were characterized by scanning electron microscopy (SEM) and XPS. The results showed that both corrosion resistance and hardness of steels play an important role in combating erosion-corrosion. Sulfide films formed on the surface were significant in understanding the erosion-corrosion behavior when both naphthenic acid and sulfur compound were present. Erosion-corrosion regimes were determined on the basis of mechanism analysis of the damage process. [source] Mass spectrometric investigation of Maltacines E1a and E1b,two members of the Maltacine family of peptide antibioticsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2005Gunnar Hagelin We have recently described the discovery of the Maltacines,a new family of cyclic peptide antibiotics from Bacillus subtilis. In this paper the mass spectrometric characterisation of two of the members is reported. A chemoselective ring opening with base to give the linear peptides was necessary before mass spectrometric characterisation could be performed. MSn of the singly and doubly charged protonated molecules gave uninterrupted series of Bn and Y,n ions that allowed determination of the amino acid sequence. By using a combination of derivatisation with phenylisothiocyanate (PITC), high-resolution mass spectrometry and H/D exchange, the identities of three unknown residues were determined. The nature and position of the cyclic structure were disclosed by a chemoselective ring opening with Na18OH and it was found to be a lactone formed between a hydroxyl of residue number 4 and the C-terminal amino acid number 12. Peptides with different combinations of P/Q and P/K at the N-terminus were synthesised to verify the sequence of the N-terminal B2 ion. The structure of the two peptides is proposed to be: E1a: cyclo-4,12(P-Q-Y-Adip-V-E-T-Y-Orn-S-Y-I-OH) and E1b: cyclo-4,12(P-Q-Y-Adip-V-E-T-Y-K-S-Y-I-OH). Adip,=,(2-amino-4,5-dihydroxypentanoic acid). Copyright © 2005 John Wiley & Sons, Ltd. [source] 4265: Inhibitory isoforms of VEGF in uveal melanomaACTA OPHTHALMOLOGICA, Issue 2010SE COUPLAND Purpose Uveal melanoma (UM) affects around 600 new patients in the UK each year with half of these being treated at the Liverpool Ocular Oncology Centre. UM is an unusual tumour in that gross chromosomal abnormalities are strongly associated with metastatic spread, especially monosomy 3 & chromosome 8q gain. Mechanisms that underlie this remain unclear. Methods Angiogenesis is a requirement for tumour survival & metastasis. Vascular Endothelial Growth Factor (VEGF) is known to be the most potent stimulator of angiogenesis and increased expression of VEGF-A is linked to enhanced metastatic potential in UM. Treatment with bevacizumab (anti-VEGF therapy) suppresses hepatic micrometastasis of ocular melanoma cells in animal models. However, VEGF-A data in UM are variable, with some studies demonstrating no correlation between VEGF-A expression and metastasis or survival. Results VEGF-A was accepted as a single pro-angiogenic family of protein isoforms generated from alternatively spliced mRNA (VEGF189, VEGF165 etc). However, recently a family of sister isoforms named VEGFxxxb, where xxx is the amino acid number and b a different six C-terminus amino acids (VEGF189b, VEGF165b) has been discovered. The VEGFxxxb variants are exactly the same size as pro-angiogenic VEGFxxx, yet are antiangiogenic. VEGF165b is down-regulated in primary cutaneous melanoma that later metastasises, and over-expression of VEGFxxxb isoforms confers a protective anti-tumour effect. Conclusion Immunohistochemical expression of pro- and anti-angiogenic VEGF-A in 19 UM was assessed using pan-VEGF-A and VEGF165b specific antibodies. A statistically significant reduction in expression of VEGF165b was observed in monosomy 3 UM (non-parametric ANOVA; p<0.05). This suggests that VEGF165b expression may be a useful predictor of UM metastasis. [source] Improved methods for carbon adsorption studies for water and wastewater treatmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Wei-chi Ying Abstract An improved method was developed to rank activated carbon in removing organic water pollutants. The simple and standardized evaluation method uses a set of four adsorptive capacity indicators: phenol, iodine, methylene blue, and tannic acid numbers; those four indicator compounds were selected because they cover the molecular size range of most organic water pollutants. An improved microcolumn rapid breakthrough (MCRB) test method was developed from the existing HPMC (high-pressure minicolumn) and RSSCT (rapid small-scale column test) methods by simplifying the experimental procedure and using readily available low-cost pump, sampler, piping, and fittings. This method can be practiced in an ordinary environmental laboratory to select the best carbon, to verify the treatment effectiveness, and to estimate the adsorption treatment cost based on the observed capacity utilization rate for carbon in the adsorber without the problems often encountered with using small and mini traditional columns. The benefits of the four-parameter carbon selection method and the MCRB method were demonstrated by adsorption isotherm and breakthrough data for several indicator compounds and organic water pollutants. These improved methods will enable efficient carbon adsorption studies necessary for more applications of carbon adsorption technology in water and wastewater treatment. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Heat Intensity and Warmed-over Flavor in Precooked Chicken Patties Formulated at 3 Fat Levels and 3 Pepper LevelsJOURNAL OF FOOD SCIENCE, Issue 9 2005Margaret E. Emrick ABSTRACT: Heat intensity and warmed-over flavor (WOF) were evaluated to determine the effects the composition of precooked, chopped, and formed chicken patties would impart on the perception of red pepper heat and the development of oxidation. Patties were formulated at 5%, 7%, and 9% fat with marinade formulated at 0%, 0.2%, and 0.4% pepper. A trained sensory panel assessed the heat intensity over 3 min using time intensity evaluation. Heat and WOF intensities of the patties were measured 5 times over a 9-wk storage period. As fat level increased, total time intensity and time to maximum heat intensity increased. Patties formulated at 7% and 9% fat were perceived to be more intense in heat than the 5% fat patties. Patties formulated at 0.2% and 0.4% pepper had less intense WOF than patties with 0% pepper level. Chemical measurement of oxidation (thiobarbituric acid numbers) indicated that increasing pepper content decreased malonaldehyde content. Incorporation of pepper into a chopped and formed meat product requires a higher pepper content at lower fat levels to impart the same level of heat intensity as in patties of higher fat level. Increasing the pepper content also will aid in decreasing production of malonaldehyde in a precooked meat product, thereby reducing the intensity of warmed-over flavor as perceived by the consumer. [source] | |||||||||||||||||||||||||