Paper Research Institute Research Articles

DEVELOPMENT OF WOOD GRINDING. 6. SIGNIFICANCE OF THE FRICTIONAL COEFFICIENT IN GRINDING OF SPRUCE WOOD

The purpose of this study was to clarify whether the wood grinding model – based on an energy balance for the grinding zone – would improve understanding of wood grinding for pulp. This study relied on previously obtained data by the Finnish Pulp and Paper Research Institute. The frictional coefficient (Pc/Pt) computed and the power-specific groundwood production (Ġw/Pt) were important x- and y- variables, respectively. Fresh spruce wood samples were ground by application of a laboratory grinder, where the stone surface speeds were 30, 15 and 7 m/s, respectively. The power-specific productivities of high- and medium-speed grindings followed one and the same mechanism, since both speeds led to a productivity of 0.99 [(kg/h)/kW]; the low-speed grinding, however, led to a level of 0.66 [(kg/h)/kW] at frictional coefficients closest to 100 mW/kW. The rate of formation of coarse rejects was – at the same frictional coefficient as before – 15.0, 4.3 and 2.3 mg/s for high-, medium- and low-speed grindings, respectively. However, the rate of fines formation determined by McNett apparatus was about ten times higher than that of formation of coarse rejects: 123.0, 42.2 and 23.7 mg/s, respectively. The fines-to-shives ratio (determined by a Somerville shive analyser) was assumed to indicate fiberisation for high-, medium- and low-speed grindings, and the true data, most close to 100 mW/kW, were 56.0, 55.9 and 36.1 units of fines-to-shives, respectively. The curves followed the same trend, but on slightly different levels. As for the important sheet properties, the tensile strengths of high-, medium- and low-speed grindings were low, medium and high, respectively: 37.1, 46.9 and 56.2 Nm/g. The light scattering coefficients of high-, medium- and low-speed grindings were low, medium and high, respectively, or as data being most close to 100 mW/kW: 59.2, 66.0 and 67.5 m2/kg, respectively. Some general conclusions may be drawn from these results. To achieve the best groundwood productivity, the frictional coefficient should be kept on a level close to 100 mW/kW. Generally speaking, it seems that high- and medium-speed grindings appeared to act as following the same mechanism as far as the productivity was concerned, but the rates of shives and fines formation did not follow such a pattern. The groundwood sheets showed lower tensile strength in high-speed grinding than in medium-speed grinding, while the light scattering coefficient was much lower for the high-speed grinding than for the medium-speed grinding. Because of its low productivity, the low-speed grinding does not seem to be useful, although high tensile strength and high light scattering of the sheets would plead for it.

RAIZ’s eucalypt genetic improvement program: The path taken and new challenges

RAIZ is a forest and paper research institute, part of The Navigator Company, a Portuguese pulp and paper company. Its eucalypt genetic improvement program started in the mid-1980s, focused mainly on E. globulus, which is well suited to the local soil and climate conditions and has outstanding wood qualities for pulp and paper production. Initially, main selection criteria were growth, survival to drought conditions, wood density and pulp yield. Cloning was the main form to transfer results into operational plantations and, as a result, rooting ability was also a key trait for successful large-scale nursery plant production. These requirements were maintained for several decades during which the program has achieved substantial gains and the E. globulus clonal forest was a reality. Meanwhile, interspecific hybridization has been tested mainly to achieve higher drought and pest resistance. As a result, the clonal program includes several hybrids. Currently, 11 clones, including three hybrids, are in nursery large-scale production, with operational gains of 30-50% over unimproved stocks, in terms of pulp produced per hectare. In the last decade, more than 250 controlled-crosses were carried out, including 70 interspecific crosses. More than 400 new clones, including 50 hybrids, and approximately 400 seed lots, including 100 hybrids and other species lots, have been tested across over 140 sites. Advanced BLUP analysis techniques are used since mid-1990’s to support strategic planning decisions, including more than 125,000 records for survival, 85,000 records for height and diameter, 57,000 pilodyn and 6,000 NIR records, collected from 219 trials, and covering about 45,000 individual genotypes. Nevertheless, efforts to face climate changes must be intensified, especially to mitigate the effects of drought and pests that currently affect a substantial portion of the forest estate. In the last 3 years, more than 100 new genotypes were selected from hybrids progeny trials involving species such as E. grandis, E. viminalis, E. saligna, E. rudis, E. urophylla, and E. tereticornis. Their multiplication and testing are undergoing, and results are expected within 5 years. In addition, an expanded approach to further diversify and strengthen of eucalypt genetic pool is being implemented, introducing species like E. cladocalyx, E. gomphocephala, E. benthamii, E. melliodora, E. punctata, or E. dunnii, aiming to enhance resilience to environmental challenges and ensuring the sustainability of Portugal's eucalyptus forests.

Larry Allen

Larry Allen, 79, died Sept. 14 in Pointe-Claire, Quebec. “Larry was an intelligent, thoughtful, adventurous, and hard-working man, devoted to family. He was a committed researcher in the field of colloid chemistry in the pulp and paper industry. He worked for the Pulp and Paper Research Institute of Canada (later FPInnovations) for 37 years. He was a leader in pulp and paper chemistry research and coedited the first book on wood resin. He coauthored over 100 publications and several patents. He was particularly proud to be able to save pulp and paper mills amounts often more than $10 million per annum in increased productivity and product quality.”—Sandy Allen, daughter Most recent title: Principal scientist, FPInnovations Education: BSc, physical chemistry, Carleton University, 1965; PhD, physical chemistry, Clarkson University, 1970 Survivors: Wife, Lee; children, Sandy, Mike, Jamie, and Dave; 11 grandchildren To recognize your late loved one or colleague, submit obituary information

Economics of advanced technologies for wastewater treatment: Evidence from pulp and paper industry

Paper mills generate large quantities of wastewater and sludge waste depending on the type of paper making processes employed. This poses several problems regarding wastewater treatment, discharge, and sludge disposal. Whenever wastewater is generated, it should be treated in wastewater treatment plants prior to being released to the environment since it can be polluting and dangerous. A study was conducted at Star Paper Mills Ltd. Saharanpur, UP to demonstrate the existing and advanced technologies for wastewater treatment. The mill uses woody raw materials such as eucalyptus, poplar, and veener chips to manufacture a wide range of industrial and cultural grade papers, such as absorbent kraft, maplitho, azure lay, and copier. We observed that the most common excess back water is from paper machines, bleach plant effluent, floor cleaning, and other sources of wastewater. High chemical oxygen demand (COD), biochemical oxygen demand (BOD), and low biodegradability are all characteristics of pulp and paper wastewater. Approximately 85–90% of the fresh water utilized is wasted. We examined the wastewater collected and evaluated from the paper mill by Central Pulp and Paper Research Institute (CPPRI). The Effluent treatment plant (ETP) at Star Paper Mills Ltd. is sufficient to facilitate satisfactory removal of suspended matter in clarifiers and oxidation of biodegradable organic matter in aeration tank. As a matter of fact, if the ETP is operated under optimal conditions, the aeration capacity is sufficient to effectively treat even higher BOD loads than the existing load.

Laudatio for Harry Goldsmith.

Professor Harry Goldsmith was born May 11, 1928, in Nurnberg, Germany. His marvelous journey in science started with his undergraduate study at Oxford University, where he received B.A. (Honours) in Chemistry and B.Sc. in Physical Chemistry in 1950 and 1951, respectively. After serving as a Technical Officer at Imperial Chemical Industries Ltd. in Manchester, UK, for six years, and as a Defence Research Board Fellow at Royal Military College of Canada for one year, Harry began his Ph.D. study in Chemistry at McGill University, Montreal, in 1958. Under the advisorship of the late Dr. Stanley G. Mason of the Pulp and Paper Research Institute, Harry completed his outstanding thesis on The Microrheology of Suspensions in 1961. After three years of postdoctoral training in the Department of Chemistry at McGill University, Harry was appointed as an Assistant Professor in the Department of Experimental Medicine in 1964 and was promoted to Associate Professor in 1969. In 1972, he became Full Professor in the Division of Experimental Medicine in the Department of Medicine at McGill, and he was Director of the Division from 1976 to 1995. In addition to his stellar research contributions, Harry played a major leadership role in the education of graduate students and the administration of the Division. Harry Goldsmith made outstanding contributions to the theory and application of rheology. He established the fundamental principle of the rheological behavior of particles in suspension by a combination of ingenious experiments and elegant analysis. The 176-page Chapter on “The Microrheology of Dispersions” by Harry Goldsmith and Stanley Mason in F.R. Eirich’s book in 1967 [1] is a Classic. This marvelous chapter established the fundamental principles of particle motion in laminar and non-uniform flows, with applications to suspension viscosity and blood rheology in large and small vessels, covering the entire field of microrheology, including blood rheology. Having started to work on blood rheology only a few years before, I found this Chapter to be a treasure and read it many times. It gave me tremendous inspiration and had great influence throughout the years on my studies on biorheology. Harry Goldsmith is not only a superb scientist, but also an ingenious designer of instruments for his sophisticated research. For example, his traveling microscopy system allowed the tracking of cells flowing in a tube by the controlled motion of the tube with a velocity that is equal and opposite to that of the cell, thus keeping the cell always in the field of observation for dynamic cinematographic filming and quantitative analysis. He has performed experiments on particles, red blood cells, white blood cells, platelets, and other types of cells. He has the unique capability to apply elegant hydrodynamic theory to analyze such quantitative experiments on individual or groups of cells in terms of their translation, rotation, collision, deformation, adhesion, and aggregation/disaggregation, thus providing novel insights on a whole range of microrheological dynamics at the cellular levels. He also deduced the molecular level force (in microdynes) of antibody–antigen bonding between two cells in a doublet.

Characterization of Refractory Organic Matter in Pulp and Paper Mill Effluents

The quality of wastewater from Japanese pulp and paper mills has been recently improved, due to regulation of effluent standards which has been stricter since the Water Pollution Control Law was enforced in 1972. However, it has not attained yet in some mills that the level of COD (Chemical Oxygen Demand) of the wastewater becomes below the environmental standard. Accumulation of refractory organic matter has been pointed out as a new problem especially for a part of the closed water area in spite of regulation of total emission. Japan Pulp and Paper Research Institute is researching this problem.As the first step of this theme, the characterization of the refractory organic matter was studied. Dissolved organic matter in wastewater was fractionated into five fractions ; hydrophobic acid, hydrophobic neutral, base, hydrophilic acid, hydrophilic neutral. Based on measurements of the degradation rates of the fractionated compo-nents, it was confirmed that the most refractory matter was fractionated into the hydrophobic acid.Furthermore, we compared softwood and hardwood kraft pulp (KP) bleaching drainages. Softwood KP bleaching drainage was more resistant to decomposition than hardwood KP bleaching drainage, and contained the hydrophobic acid in a higher ratio. In addition, the hydrophobic acid in softwood in hardwood KP bleaching drainage.In order to investigate the source of the hydrophobic acid, the each process drainage was fractionated as well. As a result, the maximum source of the hydrophobic acid was KP bleaching process. Pyrolysis GC-MS analysis of the hydrophobic acid of bleaching drainage indicated that lignin was a major composition of the refractory organic matter.

Session 6: Advances in Enzyme Science and Technology

As ethanol from lignocellulosic materials progresses to commercial fruition, finer details of the hydrolysis process are being investigated. In this session, papers were presented that dealt with several aspects of biomass conversion including substrate effects, additives to the saccharification reaction, and high performance enzymes. The influence of each one of these aspects on hydrolysis performance was analyzed by different authors. Rajeev Kumar from Dartmouth College described how the choice of pretreatment technology influences cellulose accessibility. He investigated how cellulose accessibility in poplar solids changed depending on the pretreatment method. The pretreatment methods used were ammonia fiber expansion (AFEX), ammonia recycle percolation (ARP), controlled pH, dilute acid, lime, and sulfur dioxide. The main conclusion was that cellulase enzyme site accessibility is influenced by the type of pretreatment as well as by the type and composition of the substrate. Maobing Tu from the Pulp and Paper Research Institute of Canada investigated the influence of added surfactant (Tween 80) on cellulose conversion of steam-exploded lodgepole pine and ethanol-pretreated lodgepole pine. He showed that the presence of Tween 80 resulted in a significant increase in the cellulose-to-glucose yield for the steamexploded substrate, but had no effect for the ethanol-treated substrate. In addition, the presence of surfactant increased the amount of free enzyme for both substrates implying that surfactant might be minimizing non-productive binding of cellulases to the surface. Lastly, the presence of surfactant did not affect final ethanol yields in SSF reactions with yeast. Feng Xu from Novozymes observed that cellulose oxidation had a profound impact on the rate and extent of cellulose hydrolysis by single enzymes (cellobiohydrolases) and complete cellulase mixtures (Trichoderma reesei-secreted proteins). Thermochemical pretreatments may negatively affect enzymatic hydrolysis by producing inhibitory Appl Biochem Biotechnol (2009) 154:302–303 DOI 10.1007/s12010-009-8613-0

The OptiTopo Technique for Fast Assessment of Paper Topography — Limitations, Applications and Improvements

The printability of paper is extremely dependent on the topographical properties of the substrate. Imaging instruments make it possible to obtain detailed 3D scans of paper surfaces that can be further used to calculate valuable quality predictors. A new imaging instrument, OptiTopo, based on the photometric stereo principle was developed at the Swedish Pulp and Paper Research Institute (STFI) with the advantages of an extreme acquisition speed and the possibility of simultaneously acquiring topographic and reflectance information. The topographical imaging of paper surfaces using this technique has now been investigated and improved. Eleven paper samples covering a wide range of different grades have been analyzed by OptiTopo and their scans compared to those obtained using a reference imaging technique. By applying a suitable signal treatment it is possible to improve the instrument's performance in terms of detail rendering capability. The positive results have been confirmed using visual assessment, classical statistical indicators and frequency analysis. The present limitations of the technique in relation to the physical properties of the substrate are discussed and absolute boundaries for the instrument are proposed.

Lipophilic Extractives in Eucalyptus globulus Kraft Pulps. Behavior during ECF Bleaching

The composition of E. globulus kraft pulp lipophilic extractives and their behaviour during an ECF (DEDED) bleaching sequence were investigated. Sterols; fatty acids, including several α‐ and ω‐hydroxyfatty acids; and long‐chain aliphatic alcohols are the major lipophilic extractives of the unbleached pulp. During the bleaching, about 80% of the aliphatic extractives are removed from pulp (ca. 70% of the sterols, 70% of the fatty acids, and 90% of the long‐chain aliphatic alcohols). The decrease of sterols is mainly due to the degradation of β‐sitosterol by chlorine dioxide, while the decrease of fatty acids and alcohols is essentially assigned to their extraction and elimination with the alkaline filtrates. The major chemical transformations in pulp extractives composition and structure occur in the last bleaching stages. Thanks are due to FCT and ESF for the awarding of a PhD grant to C. S. R. Freire, within the European Community Support Framework III, to the Forest and Paper Research Institute RAIZ, for supplying the industrial E. globulus kraft pulp and for the facilities conceded for the kraft pulping trials. Finally, thanks are due to Dr. Les West from Kraft Foods, USA for his kind offer of a sample of 2‐hydroxyoctadecanoic acid.

4-O-β-d-GLUCOPYRANOSYL-d-GLUCONIC ACID (CELLOBIONIC ACID) PRODUCED BY OZONATION OF CELLOBIOSE: ISOLATION BY HPLC AND ASSIGNMENT OF NMR CHEMICAL SHIFTS

Mild ozonation of cellobiose in acetic acid almost exclusively favors oxidation of the reducing end, thus yielding 4-O-β-d-glucopyranosyl-d-gluconic acid (“cellobionic acid”). This compound can be quantitatively separated from the substrate by preparative HPLC using acetonitrile/phosphate buffer on an aminopropyl silica column. The product was identified using one and two dimensional NMR techniques. 13C and 1H NMR chemical shifts are reported. †Current address: Södra Cell R&D, NO-3482 Tofte, Norway. ††Current address: The Norwegian Pulp and Paper Research Institute (PFI), Høgskoleringen 6B, NO-7491 Trondheim, Norway.

MODELLING OF HEAT TRANSFER IN HOT PRESSING AND IMPULSE DRYING OF PAPER

A modelling and simulation study regarding the heat transfer in hot pressing as well as in impulse drying of paper has been performed. The study is focused on modelling the heat transfer from a hot surface to a moist paper sheet and the heat transfer inside the paper sheet. The model is based on solving the equation for unsteady heat transfer by conduction. The model was compared with experimental data from a heated laboratory platen press and data from the experimental paper machine EuroFEX at the Swedish Pulp and Paper Research Institute (STFI) in Stockholm. The results in this study showed that a rather simple heat transfer model could be used to simulate the heat transfer in cases in which the temperature was moderate and the applied pressure did not exceed 0.5 MPa. It was also concluded that a paper could be regarded as a semi-infinite body for basis weights above 110 g/m2, considering the assumptions used in the model. It was also shown that a laboratory press could simulate heat transfer in hot pressing and impulse drying with a high degree of accuracy.

Experiments in a pilot-scale impulse unit – heat transfer and water removal rates

This is the first paper out of two dealing with heat transfer, water removal and energy efficiencies in an impulse unit in the pilot-scale research paper machine EuroFEX, located at the Swedish Pulp and Paper Research Institute (STFI) in Stockholm, Sweden. The paper produced was made of kraft pulp and with basis weights of 60-120 g/m(2). The roll surface temperature ranged from ambient temperature to 350 degreesC and the press loads were between 400-800 kN/m. The paper was produced at machines speeds of 300-800 m/min. An energy balance was conducted for the impulse unit to determine the different heat flows. It was determined that about 60% of the electrical power input was transferred to the paper web. The major heat loss was caused by wafer cooling of the induction heater. It was concluded that the heat transfer to the paper web was dependent on the roll surface temperature, the machine speed and the ingoing moisture ratio. The heat transfer to the paper web was not affected by the press load the basis weight or the roll cover. The water removal rate depended mainly on the roll surface temperature, the press load and the ingoing moisture ratio. (Less)

Experiments in a pilot-scale impulse unit – energy efficiencies

Experiments were conducted to study the energy efficiency of the impulse unit in the pilot-scale research paper machine at the Swedish Pulp and Paper Research Institute (STFI) In Stockholm, Sweden. The paper produced was made of kraft softwood pulp with basis weights of 60-120 g/m(2). The roll surface temperature ranged from ambient temperature to 350 degreesC and the press loads were between 400-800 kN/m. The paper was produced at machine speeds: of 300-800 m/min. Two different impulse drying efficiencies were defined, the total specific energy use (TSEU) and the impulse drying specific energy use (ISEU). The TSEU was defined as the electrical power input divided by the total water removal. The TSEU should be used as an overall efficiency parameter and should be compared with existing dryer section efficiencies. The TSEU was mainly dependent on the roll surface temperature, the ingoing moisture ratio of the paper web, the press load and the basis weight. In general, the impulse unit had higher energy efficiency than a modern dryer section. The ISEU was defined as the power transferred to the paper web divided by the water removal due to the elevated temperature. This value should be compared with the latent heat of vaporisation and it provides information about the water removal mechanism in impulse drying. The ISEU was found to depend on the roll surface temperature and the ingoing moisture ratio of the paper web. The ISEU was close to the latent heat of vaporisation indicating that the water removal mechanism in impulse drying was hot pressing combined with flashing of superheated water. (Less)

Radiation Stimulation of the Reactivity of Different Types of Cellulose Pulps

Institute of Nuclear Chemistry and Technology, Pulp and Paper Research Institute and Institute of Chemical Fibres carry out a joint research project in order to develop the radiation methods for modification of cellulose pulp to produce useful cellulose derivatives such as cellulose carbamate, carboxymethyl cellulose and methylcellulose. It is expected that radiation treatment should yield a final product with average degree of polymerization in the range 250–350 limiting the amount of chemicals activators used in classic methods and providing environmental benefits. In this paper the effect of 10 MeV electron beam on degree of polymerization of various cellulose pulps has been studied. The role of free radicals in degradation process is also discussed.

Occurrence of Nonylphenol Ethoxylates and Their Metabolites in Canadian Pulp and Paper Mill Effluents and Sludge

Abstract A survey of the concentrations of nonylphenol ethoxylates (NPnEO) and their metabolites in the primary and secondary treated effluent and sludge samples collected from pulp and paper mills was conducted. Through the coordination of the Pulp and Paper Research Institute of Canada (PAPRICAN), 19 Canadian and one U.S. mill of various process types and waste treatment methods supplied samples in this study. Previously developed solid-phase extraction, supercritical fluid extraction, high performance liquid chromatography and gas chro-matography/mass spectrometry methods were used for the determination of NPnEO and their metabolites, nonylphenol (NP) and the carboxylates (NPEC), in effluent and sludge samples. The levels of NPnEO ranged from <2 to 129 (median 4.5) µg/L and from <2 to 71.3 (median 5.8) µg/L for the primary and secondary effluents, respectively. The concentrations of NP varied from <0.1 to 1.32 (median 0.35) µg/L in the primary effluent and from <0.1 to 4.32 (median <0.1) µg/L in the secondary effluent. NPECs were found in only one primary and four secondary effluent samples, with an overall concentration range from <1 to 32 µg/L. These results are lower than those reported for paper mill effluents discharged into the lower Fox River, WI, USA. For the pulp and paper mill sludge, the levels of NPnEO and NP, on a dry weight basis, varied from <1 to 90.8 (median 21) µg/g and from <0.05 to 121 (median 1.3) µg/g, respectively. While NPnEO and NP were detected in nearly all sludge, their concentrations were lower than those observed for digested sewage sludge. Again, NPEC were found in only four samples, with an overall range from <1 to 18.5 µg/g. No relationship between the nonylphenolic levels in the effluent samples and the process and waste treatment types of the mill was found.

A Report on ISO/TC 6 Meeting

The ISO/TC meeting was held at the Finnish Pulp and Paper Research Institute in Espoo, Finland from May 31 to June 5. A total of 90 delegates from 21 countries participated to discuss the ISO standards related to paper, board and pulps. The international meeting is-held at intervals of 18 months. The participants broke into two groups in the working group meetings from the first day to the morning on the forth day. After the TC 6/SC 5 meeting in the afternoon on the forth day and the TC 6/SC 2 meeting on the fifth day, the TC 6 general meeting was held to close the six-day meeting. Japan was recognized as a Participating Member of TC 6 on February 12, 1999. The next meeting will be held in Whistler, Canada in September 2000.

排水の環境影響をめぐる動向と我が国の現状

Many efforts have been made to reduce the influence on aquatic organisms by pulp and paper mill effluents. In Scandinavia the new assessment program has been started to evaluate a current state of the biological impact since 1997. Also, in Canada the Aquatic Environmental Effect Monitoring has been carried out in the second phase of the program (EEM Cycle 2).Since 1996 Japan Pulp and Paper Research Institute (JPRI) has studied the effects of the effluents from 20 mills in Japan. The biological and chemical characterization confirmed that any effluent had no acute toxicity, however, the chronic toxicities, especially the effects on the reproduction of Ceriodaphnia dubia, were found to vary substantially with the mill processes. Such biological effects of the mill effluents did not depend on AOX, but the total organic compounds indicating as COD/BOD.The Toxicity Identification Evaluation (TIE), the induction of Mixed Function Oxygenases (MFO), and the bioaccumulation of EOX were investigated to elucidate the environmental affection of Japanese pulp and paper mill effluent.

Paper-to-paper friction - paper structure and moisture

Christer Fellers, Marie Backstrom and Myat Htun, Swedish Pulp and Paper Research Institute (STFI), Stockholm, Sweden and Goran Lindholm, Institute for Media Technology (IMT), Stockholm, Sweden. Keywords: Friction, Surface energy, Surface structure, Paper structure, Moisture content, Calendering, Beating, Wet pressing. SUMMARY: The purpose of this investigation was to study the effect of moisture content, paper structure and surface energy on paper-to-paper friction. The friction measurements were perfor- med using a newly developed apparatus, designed and construc- ted at STFI in cooperation with the US Forest Products Laboratory, FPL. This device allows for the measurement of the first static, S l, the third static, S3 and the kinetic, K, coefficients of friction. Experiments were conducted on different types of commercial papers and handsheets covering a wide range of sur- face energies, roughnesses and sheet structures. Different structu- res in the handsheets were created by beating, wet pressing and calendering. Friction increased with increasing moisture ratio. Friction could not however be significantly changed by the surfa- ce roughness or structure of the handsheets. Friction values for the smooth side were always found to be higher or equal to those for the rough side. It is suggested that these results and previous results in the literature can be explained by assuming that the contact area is higher for the smooth side and that it is the micro-roughness of these contact areas together with the inter- molecular interactions that take place across the interfaces that determines the paper-to-paper friction.

Report of Studying at Institute of Paper Science and Technology

The author had an opportunity to study at the Institute of Paper Science and Technology in Atlanta, Georgia for one academic year of 1996. IPST is the biggest pulp and, paper research institute in the United States whose charitable, educational, and scientific purpose evolves from the singular relationship between the Institute and the pulp and paper industry which has existed since 1929. In this report, mission of IPST, current research activities, and my impression of studying at IPST are reviewed.

Increasing the use of supplemental fibre sources in pulping

The highlights of a recent two-day workshop to address problems of fibre shortages and increasingly high delivered wood costs show that, based on their quality, availability and impact, several supplemental fibre sources can be used effectively in chemical and mechanical pulping. The workshop, held in Vancouver, British Columbia, was hosted jointly by the Pulp and Paper Research Institute of Canada and the Forest Engineering Research Institute of Canada.