scholarly journals A STUDY OF THE PHYSICO-MECHANICAL PROPERTIES IN SHORT BLEACHING SEQUENCES

2018 ◽  
Vol 42 (5) ◽  
Author(s):  
Ana Paula Almeida Ferraz ◽  
Gustavo Ventorim
Keyword(s):  
Mechanical Properties ◽  
Paper Industry ◽  
Compression Index ◽  
Total Cost ◽  
Elemental Chlorine ◽  
Lower Total Cost ◽  
Tear Index ◽  
Brightness Reversion ◽  
Reference Sequences ◽  
Cellulosic Pulp

ABSTRACT The kraft pulp of Eucalyptus spp. is relatively easy to be bleached. Therefore, studies have been carried out to reduce the number of stages of bleaching in the plant and minimize process costs. The present work aimed to evaluate the use of two short bleaching sequences in the physico-mechanical properties of cellulosic pulp as well as to compare these values to the ones obtained by usual bleaching sequences. The four bleaching sequences were ECF (elemental chlorine free), D0(E+P)D1P, AHTD0(E+P)D1P, and AHTDP and AHTD (PO). For each bleaching sequence the brightness, brightness reversion and total cost of reagents were evaluated. Physical and mechanical analyses were performed according to the methodologies of the Technical Association of the Pulp and Paper Industry (TAPPI, 2002). The AHTD (PO) sequence showed higher brightness, less brightness reversion, lower total cost and better smoothness compared to the reference sequences. However, it had a lower tear index and a lower compression index. The AHTDP sequence did not reach target brightness, however, it presented brightness reversion and lower total cost than the reference sequences. The AHTDP sequences showed high compression and smoothness, but presented a low compression index.

Structural, electronic, and mechanical properties of anatase titanium dioxide

2019 ◽  
Vol 15 (2) ◽  
pp. 306-316 ◽  
Author(s):  
Debashish Dash ◽  
Chandan Kumar Pandey ◽  
Saurabh Chaudhary ◽  
Susanta Kumar Tripathy
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Electronic Properties ◽  
Density Functional ◽  
Paper Industry ◽  
Ground Level ◽  
Basis Set ◽  
Indirect Transition ◽  
Content Type ◽  
Valence Region

PurposeThe purpose of this paper is to analyze various properties of anatase titanium dioxide (TiO2) nanoparticles. Further, it proposes to implement Linear Combinations of Atomic Orbitals (LCAO) basis set under the framework of density functional theory and outline how LCAO is able to provide improved results in terms of various mechanical properties rather than plane wave and other theoretical results.Design/methodology/approachThis paper provides an exploratory study on anatase TiO2by implementing OLCAO–DFT–LDA–LBFGS–EOS–PZ algorithms to find out various ground-level properties. The data so obtained are complemented by various analysis using mathematical expressions, description of internal processes occurred and comparison to others’ analytical results.FindingsThe paper provides some empirical insights on how mechanical properties of anatase TiO2improved by implementing LCAO methodology. From the analysis of electronic properties, it is seen that the anatase TiO2supports the inter band indirect transition from O-2p in valence region to Ti-3d in the conduction region.Research limitations/implicationsMost of the electronic properties are underestimated because a single exchange-correlation potential is not continuous across the gap. This gap can be enhanced by implementing Green’s function in place of DFT and the other way is to implement self-interaction correction.Practical implicationsThe use of anatase TiO2is primarily used for catalytic applications. This is also used to enhance the quality of paper in the paper industry. Additionally, this is used as a prime ingredient in cosmetic industry.Originality/valueThis paper fulfills an identified need to study how LCAO, another basis set, plays an important role in improving material properties.

Brightness stability of eucalyptus-dissolving pulps: effect of the bleaching sequence

Holzforschung ◽  
2017 ◽  
Vol 71 (7-8) ◽  
pp. 625-631 ◽  
Author(s):  
Jordan Perrin ◽  
Dominique Lachenal ◽  
Christine Chirat
Keyword(s):  
Heat Exposure ◽  
Dissolving Pulp ◽  
Paramagnetic Resonance ◽  
Bleached Pulp ◽  
Alkaline Peroxide ◽  
Elemental Chlorine ◽  
Brightness Reversion ◽  
Dissolving Pulps ◽  
Ultraviolet Resonance Raman

Abstract The factors governing the brightness reversion (BR) of dissolving pulps under heat exposure are investigated. Carbonyl (CO) groups were artificially introduced on fully bleached pulp by sodium hypochlorite (NaClO) oxidation. It was demonstrated that the CO groups are responsible for loss of brightness stability (BS). These groups were partly eliminated by an alkaline extraction stage (E), which improved BS. However, an alkaline peroxide stage (P) was more efficient than E to improve BS, but without any additional CO loss. Moreover, an unbleached dissolving pulp was bleached in the laboratory by elemental chlorine free (ECF) and totally chlorine free (TCF) [ozone-based] sequences to the same brightness. The very low CO content was about the same in both cases. The ECF-bleached pulp showed substantially lower BS than the TCF pulp. These results are interpreted such that the chemistry of chromophores in the unbleached pulp also governs BS. In situ detection of phenolic and quinone chromophores in bleached dissolving pulp was performed by electron paramagnetic resonance (EPR) spectroscopy and ultraviolet resonance Raman (UVRR) spectroscopy. The content of these groups was bleaching-sequence-dependent, which may be related to the BS differences.

Influence of Built Orientation on Mechanical Properties in Fused Deposition Modeling

2014 ◽  
Vol 592-594 ◽  
pp. 400-404 ◽  
Author(s):  
Sandeep V. Raut ◽  
Vijaykumar S. Jatti ◽  
T.P. Singh
Keyword(s):  
Mechanical Properties ◽  
Rapid Prototyping ◽  
Fused Deposition Modeling ◽  
Polymer Materials ◽  
Manufacturing Cost ◽  
Layer By Layer ◽  
Total Cost ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Main Material

Fused deposition modeling (FDM) is one of the thirty techniques of rapid prototyping methods that produce prototypes from polymer materials (natural or with different grades). Acrylonitrile butadiene styrene (ABS) is one of the good material among all polymer materials. It is used in the layer by layer manufacturing of the prototype which is in the semi-molten plastic filament form and built up on the platform from bottom to top. In FDM, one of the critical factor is to select the built up orientation of the model since it affects the different areas of the model like main material, support material, built up time, total cost per part and most important the mechanical properties of the part. In view of this, objective of the present study was to investigate the effect of the built-up orientation on the mechanical properties and total cost of the FDM parts. Experiments were carried out on STRATASYS FDM type rapid prototyping machine coupled with CATALYST software and ABS as main material. Tensile and Impact specimens were prepared as per the ASTM standard with different built-up orientation and in three geometrical axes. It can be concluded from the experimental analysis that built orientation has significant affect on the tensile, impact and total cost of the FDM parts. These conclusions will help the design engineers to decide on proper build orientation, so that FDM parts can be fabricated with good mechanical properties at minimum manufacturing cost.

Optimization of Heat Treatment Cycles for Automotive Parts Produced by Rheocasting Process

2006 ◽  
Vol 116-117 ◽  
pp. 505-508 ◽  
Author(s):  
Mario Rosso ◽  
Marco Actis Grande
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Performance ◽  
Treatment Cycle ◽  
Total Cost ◽  
Heat Treatment Cycle ◽  
Dimensional Precision ◽  
Heat Treated ◽  
Automotive Parts ◽  
High Level

This work aims at studying the possibility of optimising the heat treatment cycles of parts produced using the New Rheocasting process in order to reduce the total cost of the operation, attaining good mechanical properties for high performance parts. The mechanical properties and the microstructure features of the considered A 356 alloy and the relative produced parts have been analysed and studied on samples machined both from the as cast and from the heat treated compomnents. The obtained results showed the possibility of successfully modifying the T6 heat treatment cycle with economical benefits, maintaining at the same time comparable high level properties and performances, together with good dimensional precision.

Effect of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst.

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Nasko Terziev ◽  
Geoffrey Daniel ◽  
Ann Marklund
Keyword(s):  
Mechanical Properties ◽  
Picea Abies ◽  
Norway Spruce ◽  
Cell Walls ◽  
Compression Wood ◽  
Morphological Changes ◽  
Mechanical Processing ◽  
Opposite Wood ◽  
Tear Index ◽  
Control Samples

Abstract The aim of the present study was to determine the effect of a variety of abnormal fibres on the mechanical properties of paper made from Norway spruce, Picea abies (L.) Karst. Fibres representing abnormality were obtained from trees treated by irrigation and fertilisation. Moreover, fibres from compression wood and its accompanying opposite wood were isolated. The effect of dislocations on paper quality was studied on four mixtures (20, 40, 60 and 80% fibres with induced dislocations) of untreated/compressed fibres. Two more groups consisting of control untreated samples and samples with 100%-induced dislocations were also included in the test. The mechanical properties of the paper were tested and the results were compared to those of control samples. Abnormal fibres reduced the desired mechanical properties of the final paper concerning tensile strength, modulus of elasticity and tear-tensile index. Irrespective of the type of treatment, all morphological changes introduced in fibre cell walls appear to directly affect changes in the mechanical properties of the paper. Control samples had a tear index of 25 compared to 10 mN m2 g-1 of samples containing 100% dislocations. It is obvious that 20% of dislocations, an amount that is expected to be induced in pulp under mechanical processing and transport, will contribute to a decrease in tear index with an average of 3 mN m2 g-1, i.e., 10% of the total value.

scholarly journals Investigation of the Effect of Built Orientation on Mechanical Properties and Total Cost of FDM Parts

2014 ◽  
Vol 6 ◽  
pp. 1625-1630 ◽  
Author(s):  
Sandeep Raut ◽  
VijayKumar S. Jatti ◽  
Nitin K. Khedkar ◽  
T.P. Singh
Keyword(s):  
Mechanical Properties ◽  
Total Cost

scholarly journals The cost‑effectiveness of hypertonic saline inhalations for infant bronchiolitis.

2020 ◽  
Author(s):  
jefferson buendia ◽  
Ranniery Acuña-Cordero
Keyword(s):  
Cost Effectiveness ◽  
Cost Effective ◽  
Decision Makers ◽  
Hypertonic Solution ◽  
Cost Effectiveness Ratio ◽  
Tropical Country ◽  
Total Cost ◽  
Use Of Resources ◽  
Lower Total Cost ◽  
The Cost

Abstract BackgroundPharmacological treatment for bronchiolitis is primarily supportive because bronchodilators, steroids, and antibiotics, show little benefit. Clinical studies have suggested that nebulized 3% hypertonic solution is useful for infants with bronchiolitis. This study aims to evaluate the cost-effectiveness of the HS inhalations in infant bronchiolitis in a tropical country Methods Decision tree analysis was used to calculate the expected costs and QALYs. All cost and use of resources were collected directly from medical invoices of 193 patient hospitalized with diagnosis of bronchiolitis in tertiary centers, of Rionegro, Colombia. The utility values applied to QALYs calculations were collected from the literature. The economic analysis was carried out from a societal perspective.ResultsThe model showed that nebulized 3% hypertonic solution, was associated with lower total cost than controls (US $200vs US $240 average cost per patient), and higher QALYs ( 0.92 vs 0.91 average per patient); showing dominance. A position of dominance negates the need to calculate an incremental cost-effectiveness ratio.Conclusion The nebulized 3% hypertonic solution was cost-effective in the inpatient treatment of infant bronchiolitis. Our study provides evidence that should be used by decision-makers to improve clinical practice guidelines and should be replicated to validate their results in other tropical countries.

scholarly journals Minimizing the Chlorine Content in Bleached Sulfate Pulp for Sanitary Tissue products and Food Packaging

2021 ◽  
pp. 186-195
Author(s):  
Ekaterina D. Sofronova ◽  
◽  
Vadim А. Lipin ◽  
Vladimir К. Dubovy ◽  
Tatyana А. Sustavova
Keyword(s):  
Food Packaging ◽  
Raw Materials ◽  
Paper Industry ◽  
Chlorine Content ◽  
Pulp Bleaching ◽  
Allowable Limit ◽  
Elemental Chlorine ◽  
Sulfate Pulp ◽  
Pulp Production

The increasing consumption of pulp for chemical processing, including production of sanitary tissue products and other medical products, food packaging, as well as fillers for food products leads to new requirements for the quality of raw materials. The task of improving the characteristics of pulp has become particularly acute in connection with the COVID-19 epidemic: the demand for disposable nonwoven materials in direct contact with the human skin has increased several times over. The elemental chlorine free (ECF) sulfate pulp bleaching process, which uses chlorine dioxide as a bleaching agent, dominates bleached pulp production worldwide. The chlorine-containing compounds formed as a result of bleaching pollute not only waste water, but also the product itself. In the near future, it is expected that paper products made with chlorine-based bleaches may be banned for the production of sanitary tissue products and food packaging. If the products of the pulp and paper industry do not meet international consumer requirements, the pulp market for these purposes may face undesirable results. The most promising direction of modernization the existing bleaching schemes, both in terms of the process consumption parameters and the quality of the produced pulp, is the use of oxygen-alkaline bleaching in the first stage. Determination of total and organically bound chlorine content in pulp materials in accordance with ISO 11480:2017 on the advanced plant has shown, that the introduction of bleaching schemes using oxygen-alkaline agents will ensure the recommended content of chlorine compounds while maintaining the necessary characteristics of pulp for the manufacture of medical and sanitary tissue products, food packaging. However, high quality of finished products that meet consumers’ requirements is possible only if the chlorine content is controlled at all stages of pulp production, since the quantitative indicators of this substance content remain close to the upper allowable limit. For citation: sofronova e.D., Lipin v.A., Dubovy v.K., Sustavova t.A. Minimizing the Chlorine Content in bleached sulfate pulp for sanitary tissue products and food packaging. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 186–195. DOI: 10.37482/0536-1036-2021-3-186-195

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