Academic literature on the topic 'Fluting paper'

<p>Neutralsulfitkokning av björk möjliggör ett högt utbyte av hemicellulosa, vilket bidrar positivt till flutingens egenskaper och minskar vedkostnaden. Neutralsulfitkoket ska avbrytas när delignifieringen nått tillräckligt långt för att veden ska kunna defibreras skonsamt med en rimlig energiinsats, men innan nedbrytningen av hemicellulosa hunnit accelerera. Syftet med detta examensarbete var att undersöka utbytets och malningens inverkan på NSSC-massans egenskaper.</p><p>En laboratoriestudie genomfördes där massan kokades till olika utbyten och maldes vid olika insatser. Resultatet av den studien användes sedan för att ställa om kokaren och raffinörerna på lämpligt sätt vid fabriksförsöken. Massaprover togs ut efter det andra kvarnsteget och skickades för analys. De mest väsentliga egenskaperna för fluting testades genom CCT (Corrugated Crush Test), CMT (Concora Medium Test) och SCT (Short Span Compression test) men övriga konventionella egenskaper testades likväl. En avgörande egenskap för fluting är också dess krypstyvhet som undersöktes på laboratorie genom isokrona kryptester. För att få en djupare förståelse för NSSC-massans egenskaper samt kokningens och malningens inverkan på dessa utfördes även fiberkaraktärisering.</p><p>Resultatet visar att styrkan på NSSC-massan kan påverkas genom att variera både utbytet och effekten i raffinörerna. För att åstadkomma en signifikant styrkeökning krävs ett lågt utbyte tillsammans med en hög effekt i raffinörerna. Kraftiga ändringar av dessa parametrar leder dessvärre till att papperets egenskaper förändras i den grad att körbarheten på maskin kan påverkas. Studien visar även att fluting som uppfyller dagens riktvärden kan framställas kostnadseffektivt genom ett högt utbyte i kokaren och en hög insats i raffinörerna. Samtidigt erhålls då en ljusare massa, vilket kan vara betydande i vissa fall. Krypmätningarna visar samtidigt att malningen i positiv bemärkelse påverkar krypstyvheten medan utbytets inverkan är mer svårtolkat. Ett allt för högt utbyte verkar dock vara negativt ur krypstyvhetssynpunkt.</p><br><p>Neutral sulphite cooking of birch enables a high yield of hemicelluloses. This contributes positively to the properties of the flute, reduces the amount of wood needed and hence the cost. The neutral sulphite cook is to be terminated when the delignification has gone sufficiently far so that the wood can be refined mercifully with a reasonable energy input, but before the delignification has gone so far that the degradation of hemicelluloses has started to accelerate. The objective with this thesis was to examine how yield and refining affects the properties of the NSSC pulp.</p><p>A laboratory study was performed where the pulp was cooked to different yields and then beaten with different energy inputs. The results from this study were then used to determine how to set the boiler and the refiners appropriately in the paper mill trials. Pulp samples were collected after the second refiner and were then sent for analysis. The most important properties for flute were tested through CCT (Corrugated Crush Test), CMT (Concora Medium Test) and SCT (Short Span Compression test). More conventional properties were tested as well. Another important property for flute, the creep resistance, was tested in the laboratory through isochronous creep tests. To get a deeper understanding of the properties of NSSC-pulp, along with the effects of cooking and refining, fiber characterization was also performed.The results indicate that it is possible to affect the strength properties on the NSSC pulp by varying both the yield and the energy input in the refiners. To accomplish a large increase in strength, a relatively low yield is needed, along with increased refining. Large changes of those parameters may unfortunately lead to changes in paper properties in such a way that the runability on the paper machine is affected.</p><p>The results also indicate that it is possible to manufacture flute in a more cost efficient way by lowering the H-factor in the boiler while increasing the degree of refining, still keeping the strength properties above the critical values.A pulp with a higher brightness is also acquired when running the mill this way, which can be important in some aspects. The creep studies indicate that increased refining has a positive effect on the creep resistance. It is harder to make conclusions about the impact of yield, but it seems as though all too high yields affects the creep resistance negatively.</p>

Fluting-paper produced to meet the same technical specifications at three of the company’s mills, is viewed as unsatisfactory and inconsistent by some customers. This study investigated whether the company’s fluting-paper met the customers’ needs and investigated the reasons for the customer’s differing perceptions and claims of inconsistent quality. The hypothesis, investigated is therefore “the company produces fluting-paper consistently according to technical specifications that meet the customer needs”. The four objectives of this study investigated customer complaints, related the customer needs to the technical specifications, related the process measure of quality, cull, to the technical specifications and determined the reasons for the customers’ claims of inconsistent quality. The customer complaints investigation revealed differences at the mills and that fifty three percent of customer complaints were technical. The technical category was investigated to reveal “out of specification” paper, moisture, cracking, glueability and winding operations as the biggest problems that contribute to complaints. A customer survey conducted determined the customer needs and the importance of each customer need. The most important customer needs determined were consistent moisture, consistent weight and strength. The most important technical characteristics were determined using a team of technical experts and QFD principles, to be grammage, moisture and porosity. QFD also revealed that there were technical characteristics to describe the customer needs and there were specifications on all technical characteristics, except one new customer need. In the investigation of the process, cull, was consecutively compared to the technical specifications, customer needs and customer complaints using QFD. These investigations showed that tensile strength, tear and porosity were technical specifications for which paper was not culled and some mills cull paper for nontechnical reasons which are not standardized across mills. These disparities are envisaged to realize into the customers claims of inconsistent quality. The results from these four objectives therefore point out that the company does not always produce fluting-paper consistently according to technical specifications that meet the customer needs, and this hypothesis is therefore rejected

Geometrically non-linear, large scale post-buckling analyses were carried out to investigate the influence of different parameters on residual waviness (fluting) after printing in a heat set web offset printing press. Mixed implicit-explicit finite element techniques were used in the analyses. The numerical procedure was verified by experimentally acquired data. Results show that when the paper web is perfectly flat before printing, fluting patterns after drying and moisture recovery generally have higher wavelength than those typically observed in fluted samples. Initial cockles of unprinted sheets were found to have impacts on the fluting patterns and amplitudes. Among the factors investigated, ink thickness and hygroexpansivity had significant influences on fluting: increasing these factors increased fluting amplitudes.

The effects of preconditioning, moisture content and relative humidity during adsorption and desorption on the compression strength of paper were evaluated for a kraft liner and an NSSC-fluting over a range of moisture content from 1-23%. The method used was the STFI Short Span test. In general, the results show that compression strength decreases with increasing moisture content. More specifically, if compression strength is evaluated as a function of moisture content, the data points fall on a single curve for both adsorption and desorption . This result is independent of the moisture history of preconditioning of the sample. If compression strength is evaluated as a function of the relative humidity of the test environment, the moisture history and preconditioning both exert a large influence on the test result. This indicates that samples of unknown moisture history should be preconditioned in much drier atmospheres than previously recommended.

The moisture sensitivity of compression and tensile strength is compared for a range of packaging papers. It is shown that compression strength falls off more rapidly with increasing moisture content than tensile strength. This is especially true in the range up to 10% moisture content, where there is little effect of tensile strength. Results were obtained using the STFI short span compression test and tensile test carried out in silicone oil. Also included are Concora Medium Tests (CMT) for fluting. Concora Liner Tests (CLT) for liner and Ring Crush Tests (RCT) for compression. This difference in moisture sensitivity is also very evident for papers which have been given different wet strengthening treatments. For example, after 60 min. of water immersion, such wet strength papers can retain a wet tensile strength which amounts to 30 – 40% of the 50% RH value. The corresponding wet compression strength retention is only 15% to 25%. It is also shown that the tensile stiffness is more moisture sensitive than the tensile strength. The results are discussed with reference to the glass transition that cellulose and hemicelluloses at 20 degrees C pass through at a given moisture content corresponding to about 10% moisture content for a kraft paper. This transition particularly affects the moduli of the paper, while for tensile strength thermal softening apparently also has some positive effect, by reducing stress concentration.

Abstract Corrugated packages are widely used for the distribution and storage of consumer goods. These containers experience high compressive forces in stacking, and the boxes fail due to buckling and creasing in the panels. Crease lines increase the consumer product rejections as the product is thought to be damaged with the package. With increased online shopping, these problems result in higher monetary losses for the companies and increased material waste. Lattice modeling, a method to represent continuums using beams or springs, provides new opportunities to describe post-buckling creases via beam joint stiffness reduction. This may be accomplished by inducing moment releases at the lattice joints upon failure. Lattice modeling has been used to model orthotropic material properties, but not to model nonlinear orthotropic behavior or creasing. The goal is to develop a modeling method to predict the creasing failure modes and the applied force magnitudes at the onset of creasing damage for corrugated paper packages with nonlinear orthotropic properties. This manuscript modifies the analytical beam-lattice models from literature to describe nonlinear (bi-linear) orthotropic paper, and analyze corrugated board lattices via classical lamination theory. The research employs an adjusted transformed cross-section method to represent the liners and homogenized fluting. To model failure, the computational framework replaces the original rotational constraints between beams with rigid connector elements, and reduces the lattice joint rotational stiffness to zero based on a pre-defined critical connector moment or critical stress criteria. The critical stress for failure is obtained by capturing crease line formation during non-standard edge compression tests (ECTs) in the container’s loading direction. The model is then validated via box compression tests (BCTs) of regular slotted containers (RSCs). The lattice model predicts the crease lines origin and progression as well as an accurate peak BCT load. The proposed framework may be used to alter corrugated box design to reduce failures and hence the consumer rejections. This will help lower the related financial losses and address sustainability concerns.

Permanent magnet motors (PMM) have been around for two decades in the electrical submersible pumps (ESP) industry. PMM are shorter-lighter-higher power density in design and offer more than just energy savings with reduced carbon footprint; it is a technology enabler to achieve asset optimization and yet is underutilized. This paper discusses the early reporting on the first company organic PMM safely installed in a Permian Basin unconventional resource well to extract more reservoir production. The benefit to the reader is stronger confidence to apply this green technology in their wells safely and economically. To achieve sustainable first use of PMM, the ESP design and safety implications required collaboration of disciplines involving teams of Instrumentation &amp; Electrical, Production and Completion engineers, the ESP Center of Excellence, the Technical Center, Health-Safety-Environmental, and a variety of vendors over a 2-year period. Pump design and drawdown scenarios were examined while multiple safety trainings were conducted, including live demonstrations with PPE, proving the safe mitigation of hazardous voltage through proper shunting, grounding, and isolating standard operating procedures. Additionally, multiple safety devices were added (surface and subsurface) to manage the safety aspects of this technology. A final risk assessment was conducted and approved to clear the way for PMM installation. Compared to the conventional induction motor, the PMM enabled nearly 50% more power downhole for equal fluid density, comparable production and water cut without a change in pump design. Energy savings and carbon footprint reduction is 19%. Since installation, the ESP system has reduced head pressure more than 300 psi and continues to see increased production. Standard operating procedures for PMM were executed successfully and safely without incident using the free hub second source power mitigator. Four electrical technologies are included in this paper for safety of personnel and the asset as PMM bring the risk of electrical shock due to two sources of power: planned power from the grid and unplanned power from the well; the latter case the PMM is a generator and this risk is mitigated with the use of both completion and production tools such as the free hub. Additionally, the non-intrusive power measurement technology at the surface keeps personnel safe from arc-flash and electrical shock without the use of cumbersome CAT-2 PPE, a health risk in hot climates. A contactor switch at the surface helps to protect life and asset. Lastly, a common mode filter was run for carrier frequencies less than 4000 Hz to reduce or eliminate high frequency induced failures such as bearing fluting.