Search
Use the search bar or filters below to find any TAPPI product or publication.
Filters
Content Type
Publications
Level of Knowledge
Committees
Collections
Journal articles
Magazine articles
The evolution of reel statistical methods, TAPPI Journal June 2019
ABSTRACT: Multiple statistical methods for calculating the variance partition analysis (VPA) of reel data have existed for decades. In the paper industry, VPA is also commonly known as reel statistics. VPA commonly consists of total variance (TOT) that is then divided into three components: cross direction (CD), machine direction (MD), and residual (RES). A common mathematical procedure is referred to as ANOVA (analysis of variance). TAPPI Standard Test Method T 545 “Cross-machine grammage profile measurement (gravimetric method)” addresses paper testing and includes the ANOVA equations that have also been used to analyze scanning data.In the 1990s, TAPPI published TIP 1101-01 “Calculation and partitioning of variance using paper machine scanning sensor measurements,” which contained simple formulas that were easy to implement and could be used by a nov-ice to generate statistics on a spreadsheet. All involved quality control system (QCS) suppliers agreed to support this common method in their QCS. TIP 1101 was recently revised, and this paper concerns the analysis of data collected from a scanning sensor in a QCS and the creation of a common method for the calculation of reel statistics by TAPPI’s Process Control Division.
Journal articles
Magazine articles
Evaluating hardness and the S-test, TAPPI Journal March 2019
ABSTRACT: The corrugated industry typically quantifies crush resistance using the Concora corrugated medium test (CMT) on fluted medium or flat crush on combined board. These tests compress the materials until the point of complete failure of the flutes. Combined board elastically resists crushing forces until a certain point, the hardness of the structure, while additional load causes permanent damage and deformation. This study investigates how hardness can be measured directly from a load curve collected during CMT (or flat crush) testing and how it varies throughout the North American paper supply. It also explores how hardness corre-lates with the values obtained from the newly developed S-test. This new test method deserves further study as a potentially more appropriate specification for crush resistance of corrugated medium.
Journal articles
Magazine articles
Controllable anisotropic properties of wet-laid hydroentangled nonwovens, TAPPI Journal March 2019
ABSTRACT: For nonwovens, fiber orientation distribution is an important structural characteristic that directly influences the anisotropic properties of the materials. Different Vslurry/Vbelt ratios were adopted to fabricate nonwovens during the wet-laid process. The results indicated that fiber orientation distribution of nonwovens can be regulated by adopting different Vslurry/Vbelt ratios owing to the web-forming principle of wet-laid techniques. Mechanical tests showed that both wet and dry tensile strength of nonwovens in different angle directions present anisotropy under different Vslurry/Vbelt ratio parameters. A liquid spreading distribution experiment proved that liquid spreading length and area of nonwovens could be manipulated using different Vslurry/Vbelt ratios in the fabrication process. Therefore, specific anisotropic properties of wet-laid hydroentangled nonwovens can be realized by controlling the process parameters for particular end-use applications.
Journal articles
Magazine articles
Size distribution analysis of microstickies treated by enzyme mixtures in papermaking whitewater, TAPPI Journal March 2019
ABSTRACT: Microstickies present a formidable challenge for papermakers. Many strategies have been explored o control them. Enzyme treatment is a promising technology, but the mechanism of its action has not been determined, thus inhibiting further application of this new technology. This study investigated characteristics and size distributions of microstickies treated by esterase-cellulase mixtures. Determination of particle size and number was accomplished using a modified flow cytometer, which combined streaming capillary flow, laser-based particle size analysis and fluorescent dye tracing. The results showed that treatment of samples with enzyme mixtures induced size reduction of the larger microstickies. This effect was most dramatic for 1:1 ratios of esterase to cellulase. The treated particles were more stable than untreated ones. The smaller microstickies treated with some ratios of esterase and cellulase tended to aggregate over time.
Journal articles
Magazine articles
Editorial: Nanocellulose: What's next?
Many of the researchers in this field in the late 1990s and early 2000s were challenged in terms of translation research issues due to the limited production capacity of nanocellulosics on a global stage. To address this call, several pilot-plant production plants have been developed and can now deliver NC on multikilo/ton scale as these issues are gradually being resolved.
Journal articles
Magazine articles
Prehydrolysis kraft pulping of jute cutting and caddis mixture for rayon production
ABSTRACT: Jute cutting, jute caddis, and cutting-caddis mixtures were prehydrolyzed by varying time and temperature to get about 90% prehydrolyzed yield. At the conditions of 170°C for 60 min of prehydrolysis, the yield for 100% jute cutting was 76.3%, while the same for jute caddis was only 67.9%. But with prehydrolysis at 150°C for 60 min, the yield was 90% for jute cutting, where 49.94% of original pentosan was dissolved and prehydrolysis of jute caddis at 140°C in 60 min yielded 86.4% solid residue. Jute cutting-caddis mixed prehydrolysis was done at 140°C for 30 min and yielded 92% solid residue for 50:50 cutting-caddis mixtures, where pentosan dissolution was only 29%. Prehydrolyzed jute cutting, jute caddis, and cutting-caddis mixtures were subsequently kraft cooked. Pulp yield was only 40.9% for 100% jute cutting prehydrolyzed at 170°C for 60 min, which was 10.9% lower than the prehydrolysis at 140°C. For jute cutting-caddis mixed prehydrolysis at 140°C for 45 min followed by kraft cooking, pulp yield decreased by 3.3% from the 100% cutting to 50% caddis in the mixture, but 75% caddis in the mixture decreased pulp yield by 6.7%. The kappa number 50:50 cutting-caddis mixture was only 11.3. Pulp bleachability improved with increasing jute cutting proportion in the cutting-caddis mixture pulp.
Journal articles
Magazine articles
Sources, collection, and handling of noncondensible gases in modern kraft pulp mills
ABSTRACT: This work describes and discusses sources of noncondensible gases (NCG) in modern kraft pulp mills and modern NCG collection from process units where odor emissions can occur if these gases are released to the surroundings. A mill-wide overview of NCG sources and collection in modern pulp mills is provided. Using modern practices, malodorous gases can be collected to the extent that a pulp mill is essentially odor free. The key to limiting complaint-causing odors is prevention of these emissions during process disturbances, equipment malfunctions, operator errors, and other unforeseen occurrences.
Journal articles
Magazine articles
Research needs for nanocellulose commercialization and applications
INTRODUCTION: This short review deals with some applications and research needs for nanocellulosic (NC) materials; primarily cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC). Whereas CNC and BC materials are fairly homogenous, CNF materials represent a wide sector of different materials, often with a high heterogeneity. This is due to different pretreatment methods (mechanical, chemical, enzymatic), woodbased or agricultural-based materials, delignification and bleaching procedures, etc. The purpose of this comprehensive review is not to discuss the various production methods, for which the reader may consult with a selected number of reviews [1-6]; thus, the focus is on practical applications. Practical applications and potential markets were also discussed some years ago by other investigators [7-8]. Upscaling and choice of pretreatment methods, as well as economic considerations and different business models, have also been discussed, along with: œ Toxicity and environmental issues [9-10] œ The complex characterization of cellulose nanomaterials [4] The reader should also be aware of new contenders to the three classic groups of cellulosic nanomaterials, which are already in a commercial phase. These include cellulose filaments [11-12] and materials from mechanical grinding processes [13], and these materials may be nanostructures or not, depending on our classification. Finally, as indicated by the editorial on p. 275, scientists are currently taking a deep dive into the fundamental features of nanocellulosic materials [14-15].
Journal articles
Magazine articles
Effects of preincubation on the gelatinization of cassava and corn starch suspensions containing sodium hydroxide as a main component of corrugating adhesives
ABSTRACT: Effects of the preincubation temperature and the caustic-ratio, the molar ratio of sodium hydroxide to starch glucose residue, on the gelatinization of cassava starch and corn starch suspensions were studied using differential scanning calorimetry in view of utilization for corrugating adhesives. The gelatinization temperature and enthalpy change of cassava starch suspensions after the preincubation at 30°C decreased as the caustic-ratio increased, similar to those of corn starch ones: The gelatinization starting temperature (Ts) decreased considerably more than the peak temperature and the conclusion temperature (Tc). Although Ts lowered and the width of gelatinization temperature expanded, compared with those of corn starch suspensions, the two starch suspensions with the same half gelatinization transition temperature showed similar gelatinization characteristics of almost the same Ts and Tc. During 1 h-preincubations at 30°C•50°C, the starch granules with Ts that were lowered considerably below each preincubation temperature by sodium hydroxide showed limited gelatinization. The gelatinization transition did not rapidly spread over the whole suspension, but progressed stepwise in response to the increase of the causticratio and the rise of the preincubation temperature. In a prolonged preincubation at a constant temperature, Ts gradually rose at higher caustic-ratios in which stepwise gelatinization commenced. Although the starch gelatinization was irreversible and not in a stable equilibrium state for a long time, we concluded that such stepwise gelatinization progress controlled the practical preparation and use of corrugating adhesives.
Journal articles
Magazine articles
Editorial: Celebrating Wayne Carr
Editorial: Celebrating Wayne Carr: A true recycling visionary, TAPPI JOURNAL November 2017