The tribological behavior of analogue mudrock interfaces in dry, water-immersed and guar-gum solution states

2021 ◽  
pp. 107281
Author(s):  
J. Ren ◽  
F. Wang ◽  
H. He ◽  
K. Senetakis
2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Jing Ren ◽  
Siyue Li ◽  
Huan He ◽  
Kostas Senetakis

TAPPI Journal ◽  
2016 ◽  
Vol 15 (11) ◽  
pp. 731-738 ◽  
Author(s):  
KARITA KINNUNEN-RAUDASKOSKI ◽  
KRISTIAN SALMINEN ◽  
JANI LEHMONEN ◽  
TUOMO HJELT

Production cost savings by lowering basis weight has been a trend in papermaking. The strategy has been to decrease the amount of softwood kraft pulp and increase use of fillers and recycled fibers. These changes have a tendency to lower strength properties of both the wet and dry web. To compensate for the strength loss in the paper, a greater quantity of strength additives is often required, either dosed at the wet end or applied to the wet web by spray. In this pilot-scale study, it was shown how strength additives can be effectively applied with foam-based application technology. The technology can simultaneously increase dryness after wet pressing and enhance dry and wet web strength properties. Foam application of polyvinyl alcohol (PVA), ethylene vinyl alcohol (EVOH), carboxymethyl cellulose (CMC), guar gum, starch, and cellulose microfibrils (CMF) increased web dryness after wet pressing up to 5.2%-units compared to the reference sample. The enhanced dewatering with starch, guar gum, and CMF was detected with a bulk increase. Additionally, a significant increase in z-directional tensile strength of dry web and and in-plane tensile strength properties of wet web was obtained. Based on the results, foam application technology can be a very useful technology for several applications in the paper industry.


Author(s):  
Surender Verma ◽  
S. Singh ◽  
D. Mishra ◽  
Atul Gupta ◽  
Rakesh Sharma

The objective of present study was to develop colon targeted drug delivery using bacterially triggered approach through oral route. Valdecoxib (COX-2 inhibitor) was chosen as a model drug in order to target it to colon which may prove useful in inflammatory bowel disease and related disorders. Matrix tablets of Valdecoxib were prepared by wet granulation technique utilizing different ratio of Guar gum and Sodium starch glycholate. The prepared matrix tablets were evaluated for uniformity of weight, uniformity of content, hardness and in vitro dissolution study in simulated gastric and intestinal fluid (Phosphate Buffer pH-1.2, pH-6.8 and pH-7.4), followed by Dissolution study in bio-relevant dissolution media Phosphate Buffer (pH-6.8) containing rat caecal content. The results revealed that the formulated batch had released lesser quantity of drug at pH 1.2 and pH 7.4 in 2 hors whereas in biorelevent dissolution media containing rat caecal content it released significantly higher amount of drug which was also significantly higher than the dissolution media of same pH without caecal content (microflora) and it was concluded that guar gum can be used as a potential carrier for targeting drugs to colon.


2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Sharma Pankaj ◽  
Tailang Mukul

The aim of present work was to prepare colon specific delivery system of Ornidazole using different ratio of shellac, zein and guar gum. From study of various literature it revealed that shellac, zein and guar gum released drug from dosage form at the pH of 6.9, 11.5, 7-9 respectively. The main problem associated with colon targeted drug delivery system is degradation of drug in the acidic environment of stomach to circumvent the present problem different combinations of shellac, zein and guar gum were employed in the formulation of colon targeted tablet. Several preformulation parameters were determined such as melting point, FTIR spectroscopy, preparation of calibration curve, determination of λmax and partition coefficient. After the preformulation studies, next steps were preparation of core tablets, evaluation of core of tablets and coating of tablets. The data obtained from preformulation study seven formulations were developed and evaluated for various parameters. Based on evaluated parameter such as weight variation, friability, dissolution study, invitro drug release etc. the F7 formulation show better results colon targeted tablets. Drug content in F7 formulation was 95% and drug release after 6 hrs was 96%. Formulation containing combination of shellac, zein and guar gum released least amount of drug in the acidic environment of stomach and released most of the drug in colon. It is evide


Author(s):  
Audinarayana N ◽  
Anala Srinivasulu ◽  
Vellore Sruthikumari ◽  
Likitha ◽  
Ananda Deepak V

The principle in this present research is to formulate Mesalamine containing colon targeted tablets by using different polymers and evaluate the effect of different polymers in drug release pattern. The matrix tablets of Mesalamine are formulated by polysaccharides based polymers like Cellulose acetate phthalate (CAP), Ethyl cellulose (EC), Guar gum (GG) and Xanthan gum (XG) which protects the drug to release in Stomach and Small Intestine. The invitro drug dissolution investigation of F2 (GG and XG) Matrix tablet was controlled by swelling into a viscous gel in colonic pH, which have been accomplished as the best tablet. The optimized tablet F2 was found to be stable in stability study (short term) with reproducible evaluation data, which also shows the highest swelling index, increased viscosity in colonic pH. The drug release pattern from the F2 formulation follows swelling and erosion behavior. From the data it show that F2 tablets suitable for providing colon targeted drug delivery.


Author(s):  
Renan Magnol ◽  
Marciano Macedo ◽  
Marcelo de Macêdo ◽  
Cherlio Scandian

2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Purwantiningsih Sugita ◽  
Bambang Srijanto ◽  
Budi Arifin ◽  
Fithri Amelia ◽  
Mahdi Mubarok

Chitosan, a modification of shrimp-shell waste, has been utilized as microcapsule. However, it’s fragile gel property needs to be strengthened by adding glutaraldehyde (glu) and natural hydrocolloid guar gum (gg). This research’s purposes were to study dissolution behaviour of ketoprofen and infar through optimum chitosan-guar gum microcapsule. Into 228.6 mL of 1.75% (w/v) chitosan solution in 1% (v/v) acetic acid,38.1 mL of gg solution was added with concentration variation of 0.35, 0.55, and 0.75% (w/v) for ketoprofen microcapsules and 0.05, 0.19, and 0.33% (w/v) for infar microcapsules, and stirred with magnetic stirrer until homogenous. Afterwards, 7.62mL of glu was added slowly under stirring, with concentrations varied: 3, 3.5, and 4% (v/v) for ketoprofen microcapsules, and 4, 4.5, and 5% (v/v) for infar microcapsules. All mixtures were shaked for 20 minutes for homogenization. All mixtures wereshaked for 20 minutes for homogenization. Into each  microcapsule mixture for ketoprofen, a solution of 2 g of ketoprofen in 250 mL of 96% ethanol was added, whereas solution of 100 mg of in 250 mL of 96% ethanol was added into each microcapsule mixture for infar. Every mixture was then added with 5 mL of 2% Tween-80 and stirred with magnetic stirrer for an hour at room temperature. Everymixture was then added with 5 mL of 2% Tween-80 and stirred with magnetic stirrer for an hour at room temperature. Conversion of suspension into fine powders/granules (microcapsules) was done by using spray dryer. The data of [gg], [glu], and medicine’s content from each microcapsule were treated with Minitab 14 software to obtain optimum [gg] and [glu] for microencapsulation. The dissolution behaviour of optimum ketoprofen and infar microcapsules were investigated. The result of optimization by using Minitab Release 14 software showed that among the microcapsule compositions of [gg] and [glu] were 0.35% (w/v) and 3.75% (v/v), respectively, optimum to coat ketoprofen, whereas [gg] and [glu] of 0.05% (w/v) and4.00% (v/v), respectively, optimum to coat infar, at constant chitosan concentration (1.75% [w/v]). In vitro dissolution profile showed that chitosan-guar gum gel microcapsule was more resistant in intestinal pH condition (rather basic) compared with that in gastric pH (very acidic).


2020 ◽  
Vol 2020 (9) ◽  
pp. 13-17
Author(s):  
Yuriy Ryzhov ◽  
Svetlana Abramova

There is carried out a number of experiments with the purpose of analyzing SOTS impact upon both finishing productivity, and physical-chemical state and tribological behavior of surfaces machined, and also a possibility for creation according to the results of the investigations carried out a relatively universal micro-emulsion SOTS based on existing in the Ukraine the line of oils, PAV, corrosion inhibitors, alloying additives etc. As SOTS samples there were used both well-known compouds, for example, Camix, Nope Right (USA), and carbamide having in its structure boron, boron-phosphorus-containing additive, water-solvable phosphate, tributyl phosphate (oil-solvable), concentrate SOTS tribol, having in its structure compounds of boron, nitrogen and phosphorous; ethylic ether of fatty acids; methyl ether of colza oil; Sarkozyl-O having in its structure easily-decomposable chlorine compounds. From the results obtained it is possible to draw a conclusion that during finishing in the environment of water-compatible SOTS an important role in the formation of the properties of the surface worked is played by hydrocarbon components and additives which contribute to the formation of the thinnest surface layers modified with carbon and oxygen.


2020 ◽  
Vol 62 (12) ◽  
pp. 1243-1250
Author(s):  
Fahri Vatansever ◽  
Alpay Tamer Erturk ◽  
Erol Feyzullahoglu

2019 ◽  
Vol 61 (6) ◽  
pp. 543-548
Author(s):  
Aslı Gunay Bulutsuz ◽  
Mehmet Emin Yurci ◽  
Kadir Ozaltin ◽  
Witold Chrominski ◽  
Malgorzata Lewandowska

Sign in / Sign up

Export Citation Format

Share Document