Basis Weights Research Articles

Lignin-containing micro/nanofibrillated cellulose to strengthen recycled fibers for lightweight sustainable packaging solutions

As e-commerce drives the packaging growth, consumers are pushing for more sustainable packaging solutions. Considering the current societal needs, we have been able to engineer a new pathway for sustainable packaging solutions by developing lignin-containing micro- and nano-fibrillated cellulosic (LMNFCs) materials to strengthen the recycled fibers. LMNFCs from unbleached softwood pulp containing 14.4% lignin at high and low fibrillation levels were produced. Packaging papers from recycled old-corrugated containers were strengthened with LMNFCs with varying addition levels of 1 wt% to 3 wt% at two basis weights. The results show 2 wt% addition of LMNFC can enhance strength at low levels of fibrillation, and that basis weight can be reduced by 16.7%, from 150 gsm to 125 gsm, while maintaining a burst strength of 49-53 lbf. Reduction in basis weight and high lignin content of LMNFC also enhanced dewatering during sheet formation with the lowest increase in drainage time, 9%, relative to the 150 gsm with no LMNFC. The techno-economic analysis supports the feasibility of using LMNFC to produce lightweight and sustainable packaging materials at industrial scale with an 8% reduction in fiber cost.

Effect of solution blown nanofibers on Mode‐I fracture toughness and dynamic mechanical properties of carbon fiber‐reinforced composites

AbstractIn this study, solution‐blown nanofibers were coated on carbon fiber (CF) fabrics to improve Mode‐I fracture toughness and dynamic mechanical properties of the composite laminates. Nanofiber coatings of various basis weights were directly spun over CF fabrics, which were then formed into composite laminates via vacuum‐assisted resin transfer molding. A double cantilever beam test was conducted to analyze the Mode‐I fracture toughness of CF‐reinforced epoxy composites. The results showed that solution‐blown nanofiber coatings stabilized the crack propagation and increased the delamination strength hence increased the Mode‐I fracture toughness by nearly 48% for the addition of 1 g/m2 nanofibrous web. Dynamic mechanical analysis was performed to investigate the effect of nanofibers on the stiffness of materials and the homogeneity of samples. Storage modulus, loss modulus, and damping factor were calculated, and corresponding Cole‐Cole plots were drawn. DMA results showed that the stiffness of the composite sample increased up to 17% even after a minor amount (1 g/m2) of nanofiber coating.

Effects of increasing dietary inclusion of camelina cake on growth performance of growing-finishing pigs.

The objective of this experiment was to determine the dietary inclusion rate of camelina cake (CC) that would support the growth performance of growing-finishing pigs similar to that of a corn-soybean meal-based diet. Pigs (n = 192; BW = 35.2 kg; Duroc x (Yorkshire x Landrace)), balanced for sex and initial weight, were assigned to pens (8 pigs/pen) and pens were assigned randomly to one of four dietary treatments (6 pens/treatment). Treatments consisted of a non GMO corn-soybean meal control diet (CON), or CON containing 5% (5CC), 10% (10CC), or 15% (15CC) camelina cake. Feed disappearance on a pen basis and individual body weights of pigs were recorded every other week to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) on a pen basis. Prior to harvest, real-time ultrasonic measurements of back fat depth and loin eye area were collected on all live pigs. Pigs were harvested as a single group at about 23 weeks of age at a commercial abattoir. Data were analyzed using Proc Glimmix with dietary treatment as a fixed effect and pen serving as the experimental unit. Growth performance data collected over time were analyzed using repeated measures within the Proc Glimmix procedure. Overall, pigs fed CON exhibited similar ADG to those consuming 5CC and higher ADG than pigs consuming 10CC and 15CC diets (1.10 kg vs. 1.05 kg for 10CC and 1.02 kg for 15CC; P < 0.05 for both mean comparisons). Pigs fed CON consumed more feed than pigs fed any of the CC diets (ADFI = 2.66 kg for CON vs. 2.46 kg for 5CC, 2.46 kg for 10CC and 2.47 kg for 15CC; P < 0.05 for all). These differences resulted in heavier (P < 0.05) CON-fed pigs at marketing than 10CC or 15CC-fed pigs. There were no differences in any carcass traits analyzed. From these data, we conclude that feeding up to 5% CC in corn-soybean meal-based diets did not negatively influence growth performance, or carcass traits of growing-finishing pigs.

Ultra-lightweight fiber-reinforced envelope material for high-altitude airship

In this work, fiber-reinforced laminates for the envelope (hull) of high-altitude airships were developed using a novel design concept utilizing ethylene vinyl alcohol (EVOH) as the adhesive component layer with high gas barrier properties. The other component layers of the laminates included poly(p-phenylene benzobisoxazole) (Zylon®) fabric, metalized Mylar® (polyester) and metallized Kapton® (polyimide). The envelope materials were developed in two different strength categories. In the first category, three laminate designs were developed with strength ranging from 945–970 N/cm. The second group had one laminate design with a strength of 702 N/cm. These laminates with basis weights ranging from 103–113 g/m2, are the lightest envelope materials developed to date. As a function of their high strength and low basis weights, the new envelope materials have significantly higher specific strength (ranging from 911–925 kN.m/kg) compared to other envelope constructions published in the open literature. Other outstanding properties of the laminates include low helium permeability ranging from 0.4–8.0 cc/m2.24 hr.1 atm, high tear strength, UV and visible light (UV–Vis) resistance, and high creep resistance.

Electrospun Nanofibre Air Filters for Particles and Gaseous Pollutants

Nanofibre filters may offer new properties not available in commercial fibre filters. These include a higher surface area and the ability to include novel materials within the fibres. In addition the small size allows potential gains in performance due to the slip-flow phenomenon in which normal gas viscosity does not apply to objects smaller than the mean free path of the gas. We tested the properties of novel electrospun fibre filters generated from polyvinyl alcohol solutions, optionally embedded with nano-grains of photocatalytic TiO2 and activated charcoal. The tested materials exhibited pressure drops in the range of 195 Pa to 2693 Pa for a face velocity of 5.3 cm/s and a removal efficiency greater than 97% for 12–480 nm particles. Basis weights for the filters ranged from 16.6 to 67.6 g/m2 and specific surface areas ranged from 1.4 to 17.4 m2/g. Reactivity towards volatile organic compounds (VOCs) was achieved by irradiating the photocatalytic filters with ultraviolet light. It is necessary to solve the problems connected to the absorbance of VOCs and further reduce the resistance to airflow in order for these filters to achieve widespread use. The incorporation of reactive air filtration into building ventilation systems will contribute to improved indoor air quality.

Development of a novel test method for the measurement of fuzz in nonwovens

Quantitative evaluation of fuzz in nonwovens is of significant interest as nonwoven products are typically subjected to abrasion during service. In this work, the initial level of fuzz and its growth were quantified for polypropylene (PP) spunbond thermally point-bonded nonwovens in three different basis weights representing the range of nonwovens used in most disposable products. We used noncontact confocal laser microscopy coupled with three-dimensional image analysis to quantify the volume of fuzz. Fuzz data generated by using this novel test set-up was verified by statistical analysis, resulting in repeatable and reproducible results. This represents the first in a series of publications dedicated to the study of fuzz.

Effect of electrospinning conditions on β-phase and surface charge potential of PVDF fibers

Electrospun polyvinylidene fluoride (PVDF) fibers, can act as electrets in filtration applications. Relevant to this is the extent at which electrospinning conditions affect the beta-phase content of PVDF fibers. The beta-phase content is a strong factor in measured charge potentials on PVDF fiber mats. PVDF fiber mats were electrospun from three different polymer solution concentrations (10, 14 and 18 wt%) to fabricate mats of three average fiber diameters (328, 780, 1167 nm) respectively and of five different basis weights (10, 20, 30, 40, and 50 g/m2). Furthermore, fiber mat samples were electrospun at varying conditions of applied voltage (21, 24, 27 and 30 kV), solution flow rates (2, 5 and 8 ml/h), needle-tip to collector distances (12, 15, 18, 22 cm) and collector drum rotation speeds (5, 45, 100 rpm) while holding constant the 10 wt% solution concentration and 20 g/m2 mat basis weight. SEM images and FTIR spectra were analyzed to estimate the average fiber diameter and amount of beta-phase content. The apparent surface charge potential was measured using a custom-made Faraday Bucket. The solution compositions, flow rates, and needle-tip distance had moderate effects on fiber diameters and on the beta-phase content. The measured surface potential was found to be directly proportional to beta-phase content. The rotation rate of the drum collector had negligible effect on fiber diameter but did affect the beta-phase and surface potential. The measured surface charge potential was directly proportional to the basis weight and inversely proportional to the fiber diameter.

Branched nanofibers with tiny diameters for air filtration via one-step electrospinning

Engineering the surface morphology of fibers has been attracting significant consideration in various areas and applications. In this study, polyvinylidene fluoride (PVDF) branched nanofibers with a diameter of less than 50 nm are electrospun directly at a low relative humidity by adding tetrabutylammonium chloride. The effects of the branched structure on the specific surface area and pore size distribution are investigated, and the filtration properties of the air filter based on branched nanofiber webs with different basis weights are studied. The results exhibit that the air filter based on PVDF branched nanofibers with the basis weight of 1 g/m2 has an outstanding filtration efficiency (99.999%) to 0.26 µm sodium chloride particles under the pressure drop of 126.17 Pa. We believe that this study can be used as a useful reference for the preparation of branched nanofibers through one-step electrospinning.

A Highly Porous Nonwoven Thermoplastic Polyurethane/Polypropylene-Based Triboelectric Nanogenerator for Energy Harvesting by Human Walking.

A highly porous nonwoven thermoplastic polyurethane (TPU)/Polypropylene (PP) triboelectric nanogenerator (N-TENG) was developed. To fabricate the triboelectric layers, the TPU nanofiber was directly electrospun onto the nonwoven PP at different basis weights (15, 30, and 50 g/m2). The surface morphologies and porosities of the nonwoven PP and TPU nanofiber mats were characterized by field-emission scanning electron microscopy and porosimetry. The triboelectric performance of the nonwoven TPU/PP based TENG was found to improve with an increase in the basis weight of nonwoven PP. The maximum output voltage and current of the TPU/PP N-TENG with 50% PP basis weight reached 110.18 ± 6.06 V and 7.28 ± 0.67 µA, respectively, due to high air volume of nonwoven without spacers. In order to demonstrate its practical application as a generator, a TPU/PP N-TENG-attached insole for footwear was fabricated. The N-TENG was used as a power source to turn on 57 light-emitting diodes through human-walking, without any charging system. Thus, owing to its excellent energy-conversion performance, simple fabrication process, and low cost, the breathable and wearable nonwoven fiber-based TENG is suitable for large-scale production, to be used in wearable devices.

Neural Network Repair of Lossy Compression Artifacts in the September 2015 to March 2016 Duration of the MMS/FPI Data Set.

During the September 2015 to March 2016 duration (sometimes referred to as Phase 1A) of the Magnetospheric Multiscale Mission, the Dual Electron Spectrometers (DES) were configured to generously utilize lossy compression. While this maximized the number of velocity distribution functions downlinked, it came at the expense of lost information content for a fraction of the frames. Following this period of lossy compression, the DES was reconfigured in a way that allowed for 95% of the frames to arrive to the ground without loss. Using this high‐quality set of frames from on‐orbit observations, we compressed and decompressed the frames on the ground to create a side‐by‐side record of the compression effect. This record was used to drive an optimization method that (a) derived basis functions capable of approximating the lossless sample space and with nonnegative coefficients and (b) fitted a function which maps the lossy frames to basis weights that recreate the frame without compression artifacts. This method is introduced and evaluated in this paper. Data users should expect a higher level of confidence in the absolute scale of density/temperature measurements and notice less sinusoidal bias in the velocity X and Y components (GSE)

Analysis of Factors Influencing the Resistance of a Type of Air Filter Paper Based on SPSS

The thicknesses, basis weights and resistances of a type of air filter paper randomly sampled were tested by experiment. The statistical analysis of the test data was carried out by multiple linear regression analysis of the statistical software SPSS19.0. The conclusion were as follows: when the paper had a basis weight variation from 55.2 g/m2 to 59.8g/m2 and a thickness variation from 0.385mm to 0.406mm, α=0.05, basis weight variation on resistance existed significant influence, the regression equation was Δp=2.551w, correlation coefficient R2=0.83; thickness variation on resistance did not exist significant influence.

Modeling electrospun fibrous structures with embedded spacer particles: Application to aerosol filtration

This work presents a physics-based modeling technique to simulate the 3-D microstructure of electrospun fibrous media with embedded spacer particles. The model accepts inputs like diameter, basis weight, deposition velocity, and bending properties for the fibers as well as diameter and basis weight for the spacer particles. The model then predicts morphological parameters like filter porosity and filter thickness, among many others. The work presented in this paper is the first to report the effects of spacer particles with different diameters or basis weights on the thickness and solid volume fraction of spacer-embedded fibrous media. Such morphological information is then used for collection efficiency and pressure drop predictions when challenged with aerosol particles in the particle diameter range of 20 nm to 5 µm at a face velocity of 10 cm/s. Our results indicate that adding spacer particles to a fibrous filter can lower its collection efficiency and pressure drop, but the reduction in the pressure drop will be at a higher rate resulting in better filters, i.e., filters with better quality factors.

High filtration efficiency fluffy material: nano-fiber constructing gradient structure on recycled curved PET micro-fibers web

High efficiency filtration materials focus on electreted melt-blown polypropylene nonwoven and nano-scale fibers membrane in industry. However, the charge decay and the balance of efficiency and resistance are still facing challenges on research and practical applications. In this research, combined with traditional electrospinning and carding process, a simple and new fluffy gradient filtration material was designed by constructing nano-scale poly(lactic acid) (nano-PLA) fiber membranes on recycled three-dimensional curved poly(ethylene terephthalate) (R-PET) micro-fibers webs. Influences of basis weights of nano-PLA membranes and curved types of R-PET fibers on the filtration performance and the dust-holding capacity of R-PET/nano-PLA mats were investigated. Besides, the filtration mechanism of R-PET/nano-PLA mats was systemically studied. Results show that R-PET with zigzag curve (R/Z-PET) possesses the highest filtration efficiency of 99.992% comparing with 99.517% of linear R-PET, the pressure drop fall to 201.11 Pa, and a quality factor level up from 0.024 to 0.047 Pa−1. The pressure raising rate of the R/Z-PET/nano-PLA mat is the slowest. R/Z-PET fibers with a folding angle of 90° benefit to decrease the friction between fiber and particles when the location angle of zigzag fiber is 45° along the airflow direction, which decrease the pressure drop at high filtration efficiency. Surface residual charges contribute some effect on the overall filtration performance of the R-PET/nano-PLA mat. A new way of simple curved micro-PET fiber combining with nano-scale fibers provides an industrial available path to mass production of high efficiency filtration material serving for air pollution control without electret process.

Convex Identification of Minimal Function Bases for Cylinder Pressure by Using Pressure Values as Basis Weights

Estimating cylinder individual pressures using flywheel angular measurements is difficult, foremost because several input signals must be estimated from one single measurement signal. Since the pressures cannot vary arbitrary, estimation can still be possible, but it leaves little room for robustness. To take most use of data and models, it is suggested here to parameterize pressures using a function basis. For a general physics-based engine model, it is shown how the information content in the angular measurement is limited, implying that only a few parameters per cylinder can be estimated. If small deviations in the combustion are to be identified, a very parameter efficient basis is, therefore, needed. By showing that the basis can be chosen such that its weights are pressures at distinct angles, a convex optimization problem to determine optimal basis functions is derived. The method is applied to extensive cylinder pressure data for a six-cylinder diesel engine in a case study with induced combustion faults. The result is that only three to four free parameters per cylinder are needed to achieve a close fit, and a provided analysis suggests that this may enable the design of robust estimators.

Multi-Layer Filters: Adsorption and Filtration Mechanisms for Improved Separation.

Filters made of cellulose fiber and perlite particles were prepared using a wet laying papermaking technique. Polyamide-amine-epichlorohydrin (PAE) was added to provide wet strength. Filters were prepared at two different total basis weights of 200 and 400 grams per square meter (gsm). Single and multi-layered filters were structured for each total basis weights. The effect of total basis weights and multi-layered structure on methylene blue adsorption and silicon dioxide (SiO2) particle filtration was investigated. Methylene blue adsorption was performed in two modes: constant pressure and constant flow rate. In both operation modes, the adsorption capacity of multi-layered filters was significantly higher (16–100%) than for single-layer filters at the same overall weight. The effect of layer separation was also characterized using polypropylene separators and tested under constant flow rate operation. Separators provided more effective methylene blue adsorption by generating a well-distributed flow. Filtration performance was quantified with 0.5 μm silicon dioxide particles under constant pressure conditions; this is to mimic bacteria rejection. Filtration capability of SiO2 particles was reduced slightly (12%) with decreasing individual filter layer thickness regardless of the multi-layered structure. Filtering polyethylene glycol (PEG) molecules with two different molecular weights was performed; however, no rejection was recorded. The filter internal pore structure was visualized by 3D-X ray computed tomography and the void fraction was quantified. 400 gsm single layer presented areas of low fiber density forming pores, while the pore volume decreased for thinner filter layers.

Production and mechanical characterization of free-standing pigmented paper coating layers with latex and starch as binder

The mechanical properties of paper coating layers are important in various converting processes such as printing and folding of the paper. A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these coating layers were characterized. Free-standing films with two types of binder formulations, pure latex or latex-starch combinations, with different binder content were prepared through an innovative film forming method that allows uniform drying of the coating layer while minimizing cracking. Tensile and flexural samples were cut out of these films. Tensile and flexural tests were carried out on samples and the results were compared. Tensile and flexural moduli were found to be similar. However, both stress at failure and strain at failure were higher in flexural tests compared to those in tensile tests. Three different types of paper were coated with these formulations and their failure during printing was evaluated through a standard ink picking test. Papers with different basis weights and porosities were found to have different picking resistance values. An interesting result was that the picking resistance did not correlate with the elastic modulus of the coating, but with the strain at failure behavior. This result indicates that the stiffness of the coating layer is not as critical during printing compared to its flexibility.

Flexible spray coating process for smooth nanocellulose film production

A novel rapid method for high throughput production of smooth nanocellulose (NC) films by spray coating was communicated recently. In this method, we employed spray coating to produce wet films on stainless steel plates moving on a conveyor, forming free-standing films with interesting structural, mechanical and surface properties upon drying. In this research, we investigate the range of mechanical and physical properties of nanocellulose films prepared by spraying. Furthermore, a comparison with NC films prepared via conventional vacuum filtration was conducted to evaluate the suitability of this method as an alternative film preparation process. One set of experiments was completed where the solids concentration of the suspension was fixed at 1.5 wt% and the conveyor velocity was varied, while two series of experiments were completed where the solids concentration of the suspension was varied and the conveyor speed was fixed at either 0.32 or 1.05 cm/s. By varying speed and solids concentration, spray-coating was found to allow efficient production of films with basis weights ranging from 38 to 187 g/m2, with film thicknesses ranging from 58.4 to 243.2 μm, respectively. There was a universal linear relationship between the thickness and basis weight, independent of the process conditions. The optical uniformity of film was also noticeably dependent on the spraying process. The optical uniformity index of films, relative to vacuum filtered films, increased with conveyor speed at 1.5 wt% solids concentration and was independent of solids concentration at low speed. Forming at the higher speed of 1.05 cm/s produced a maximum in optical uniformity in the range 1.5–1.75%, with these films being more uniform than conventional films produced through vacuum filtration. The most uniform films produced by spraying also had a similar tensile index to films made via vacuum filtration. With an understanding of these parameters and effects, we demonstrate this method to be a more time efficient alternative method to produce uniform films where the properties can be tailored to the required application.

Healthcare Event and Activity Logging.

The health of patients in the intensive care unit (ICU) can change frequently and inexplicably. Crucial events and activities responsible for these changes often go unnoticed. This paper introduces healthcare event and action logging (HEAL) which automatically and unobtrusively monitors and reports on events and activities that occur in a medical ICU room. HEAL uses a multimodal distributed camera network to monitor and identify ICU activities and estimate sanitation-event qualifiers. At the core is a novel approach to infer person roles based on semantic interactions, a critical requirement in many healthcare settings where individuals’ identities must not be identified. The proposed approach for activity representation identifies contextual aspects basis and estimates aspect weights for proper action representation and reconstruction. The flexibility of the proposed algorithms enables the identification of people roles by associating them with inferred interactions and detected activities. A fully working prototype system is developed, tested in a mock ICU room and then deployed in two ICU rooms at a community hospital, thus offering unique capabilities for data gathering and analytics. The proposed method achieves a role identification accuracy of 84% and a backtracking role identification of 79% for obscured roles using interaction and appearance features on real ICU data. Detailed experimental results are provided in the context of four event-sanitation qualifiers: clean, transmission, contamination, and unclean.

Effect of Bicomponent Fibers on Sound Absorption Properties of Multilayer Nonwovens

In this study sound absorption properties of multilayer nonwovens with bicomponent fibers have been derived compared with homocomponent fibers. Multilayer nonwovens obtained by polyester fibers consisted of three layers. The top and bottom layers were spunbonded nonwoven and middle layer was meltblown nonwoven sandwiched between them. Each layer was produced separately to compose unbonded three-layered nonwoven structures. Four different spunbonded nonwoven fabrics having a basis weight of 40 gsm made from four different polyester cross-sectional fibers (homocomponent round and trilobal, bicomponent round and trilobal). Five different meltblown nonwoven fabrics having five different basis weights ranging 100 gsm to 200 gsm were made from polyester round cross-sectional fibers. Spunbonded/ Meltblown/ Spunbonded (SMS) type unbonded multilayer nonwovens had basis weights ranging 180 gsm to 280 gsm. The effect of basis weight on sound absorption performance of multilayer nonwovens has been evaluated in the study. All results have been analyzed statistically. Results show that three-layered nonwoven structures including bicomponent fibers as outer layers had better sound absorption performance than nonwoven structures including homocomponent fibers. This effect becomes more significant as the basis weight increases, resulting insound absorption coefficients.

Influence of flock coating on bending rigidity of woven fabrics

This work presents the preliminary results of our efforts that focused on the effect of the flock coating on the bending rigidity of woven fabrics. For this objective, a laboratory scale flocking unit is designed and flocked samples of controlled flock density are produced. Bending rigidity of the samples with different flock densities are measured on both flocked and unflocked sides. It is shown that the bending rigidity depends on both flock density and whether the side to be measured is flocked or not. Adhesive layer thickness on the bending rigidity is shown to be dramatic. And at higher basis weights, flock density gets less effective on bending rigidity.