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PL
Zbadano zachowanie się sorbentu wapiennego o rozdrobnieniu 90-400 μm podczas jednoczesnego procesu kalcynacji i siarczanowania (JKS). Doświadczenia prowadzono w zakresie temperatury oksyspalania (850-1000°C) przy stałej zawartości SO₂ (3000 ppm) i zmiennym stosunku obj. CO₂/O₂ (20/80, 50/50, 70/30). Stosując technikę porozymetrii rtęciowej, określono zmiany struktury sorbentu. Wyznaczono również współczynnik reaktywności oraz sorpcji bezwzględnej siarki badanego materiału.
EN
Ca sorbents with a grain size 90-400 μm were placed in combustion furnace and heated at 850-1000°C in CO₂ and O₂-contg. atm. in amts. of 20/80, 50/50 and 70/30 by vol. resp. and 3000 ppm of SO2. The degree of calcination and sulfation of the sorbents during the process was detd. The indices of reactivity and absolute sorption were calcd. The sorbent porosity was detd. by using a Hg porosimeter. Open, intra and intergranular porosity and mean diam. of sorbent particle were evaluated. The effective simultaneous calcination and sulfation were closely related to changes in porosity of sorbent. The optimum temp. for the capture of S O₂ was 900-950°C in the presence of flue gas contg. 70% C O₂ and 30% O₂.
EN
The use of cast aluminium has still increased, so have the mechanical property requirements. By casting and also in other metallurgical processes, the inclusions enter to the molten aluminium alloy and it exhibits poor ductility or toughness. It can cause a variety of problems in the manufacture of aluminium alloy castings. Therefore, the purification of the molten aluminium alloy is one of the most important processes for improving the quality of Al-products. Filters have been used for many years in order to improve the quality of castings. The inclusions in molten secondary AlSi7Mg0.3 cast were removed using depth filtration by ceramic foam filters of 20 ppi porosity. Were used 4 types of ceramic filters in 2 thicknesses (15 and 22 mm); Brinell hardness and porosity were measured. Quality of microstructure (occurrence of oxidic particles and larger non-metallic inclusions) was observed. Experimental results show that the insertion of ceramic filters into the inlet system has contributed primarily to a decrease in porosity. On the microstructure, the inclusion of filters was not significantly reflected.
EN
Eni oilfield has been experiencing production decline with increase in water output. The implementation of enhanced oil recovery (EOR) can help to extract some percentages of the original oil in place (OOIP). EOR methods are capital intensive and few are environmental hazardous. In a bid to address this issues, this paper discusses on an alternate economically viable enhanced oil recovery technique which has the potential to curb the challenges of other conventional EOR methods. This work suggested a 3 stage approach of applying microbial enhanced oil recovery (MEOR) method for oil recovery in Eni field. The reservoir characteristics in Eni field were studied, the average porosity value of the reservoirs is between 0.238 and 0.241, while water saturation ranges between 0.127 and 0.13. Other production data include; Initial reservoir pressure which ranges from 2328 to 2553 Psia and has a reservoir temperature ranging from 170°F to 180°F. The Average API gravity ranges from 20.5 to 34.2, while the initial GOR ranges from 350 to 396. Oil viscosity was between 0.57cp to 2.57cp while gas viscosity was between 0.65cp to 0.67cp. The reservoir characteristics and parameters were found suitable for the application of MEOR technique for effective oil drainage from the delineated reservoir compartments. Microbial flooding was found to be matured in reservoirs with temperature less than 200°F, brine salinity not more than 100,000 ppm, water depth not more than 3500m and permeability should be above 30 (Md). It is recommended that MEOR approach should be applied in Eni Oilfield for increment of oil production and reduction in water cut due to its efficiency and economic viability.
EN
An unsteady flow of heat and species transport through a porous medium in an infinite movable vertical permeable flat surface is considered. The hydromagnetic chemical reactive fluid flow is stimulated by the thermal and solutant convection, and propelled by the movement of the surface. The formulated nonlinear flow equations in time space are solved analytically by asymptotic expansions to obtain solutions for the flow momentum, energy and chemical concentration for various thermo-physical parameters. The existence of flow characteristic is defined with the assistance of the flow parameters. In the study, the impact of some pertinent flow terms is reported and discussed. The study revealed that the species boundary layer increases with a generative chemical reaction and decreases with a destructive chemical reaction. Also, arise in the generative species reaction term reduces the flow momentum for the cooling surface. The impact of other flow governing parameters is displayed graphically as well as the fluid wall friction, wall energy and species gradients. The results of this study are important in chemical thermal engineering for monitoring processes to avoid solution blow up.
EN
For efficient reservoir management and long-term field development strategies, most geologists and asset managers pay special attention to reservoir chance of success. To minimise this uncertainty, a good understanding of reservoir presence and adequacy is required for better ranking of infill opportunities and optimal well placement. This can be quite challenging due to insufficient data and complexities that are typically associated with areas with compounded tectonostratigraphic framework. For the present paper, data analysis and variography were used firstly to examine possible geological factors that determine directions in which reservoirs show minimum heterogeneity for both discrete and continuous properties; secondly, to determine the maximum range and degree of variability of key reservoir petrophysical properties from the variogram, and thirdly, to highlight possible geological controls on reservoir distribution trends as well as areas with optimal reservoir quality. Discrete properties evaluated were lithology and genetic units, while continuous properties examined were porosity and net-to-gross (NtG). From the variogram analysis, the sandy lithology shows minimum heterogeneity in east-west (E–W) and north-south (N–S) directions, for Upper Shoreface Sands (USF) and Fluvial/Tidal Channel Sands (FCX/TCS), respectively. Porosity and NtG both show the least heterogeneity in the E–W axis for reservoirs belonging to both Upper Shoreface and Fluvial Channel environments with porosity showing a slightly higher range than NtG. The vertical ranges for both continuous properties did not show a clear trend. The Sequential Indicator Simulation (SIS) and Object modelling algorithm were used for modelling the discrete properties, while Sequential Gaussian Simulation (SGS) was used for modelling of the continuous properties. Results from this exercise show that depositional environment, sediment provenance, topographical slope, sub-regional structural trends, shoreline orientation and longshore currents, could have significant impacts on reservoir spatial distribution and property trends. This understanding could be applied in reservoir prediction and for generating stochastic estimates of petrophysical properties for nearby exploration assets of similar depositional environments.
EN
In the Polish part of the Carpathian Foredeep, an intensification of gas exploration and exploitation from Miocene strata took place in the middle of the twentieth century. In spite of a good degree of geological and reservoir recognition, the area of the Carpathian Foredeep is still considered to be prospective for the discovery of new gas reservoirs. Here we analyse statistically selected reservoir parameters of Miocene deposits, such as total porosity, effective permeability and reservoir water inflow. These parameters have been determined on the basis of interpretations of results of well logs and reservoir tests with tubular bed samplers (DST, Drill Stem Test). Analytical results in the form of regression and dependence of the logarithm of permeability as a function of porosity show a weak correlation. However, in the study area, the distribution of porosity values for Miocene strata is close to normal.
EN
This research work discusses both the physical and durability characteristics of newly blended cement containing waste crushed brick. This waste is used as a partial substitution for clinker in cement. Thus, blended cements are obtained by grinding and homogenizing clinker, waste brick, and gypsum. Four compositions containing 0%, 10%, 20%, and 30% of waste materials were prepared and submitted to various characterization tests. The introduction of brick powder improved the physical characteristics, therefore; it improved the mechanical properties and durability performance of the new cement compared to the reference, prepared with 0% addition. More particularly, it resisted sulfuric acid (H2SO4) attack after fixation of portlandite by pozzolan.
EN
This experimental study aimed to use the ultrasonic pulse velocity method (UPV) in order to investigate the effect of rubber tire waste content and transducers’ diameters and frequencies on the evolution of ultrasonic velocities in time and to elucidate the correlations between UPV and the properties of various concrete mixtures. The incorporation of this waste involved volume substitution (0, 5, 10, 15 and 20%) of fine aggregates (sand) by rubber waste (RW) granulates. The dry unit weight, porosity, compressive and flexural strengths, and velocity of ultrasonic waves with different transducers - which presents the non-destructive technique - were evaluated. Rubberized concrete mixtures showed increases in porosity with lower dry unit weight compared to the control concrete. Compressive strength, flexural strength and ultrasonic velocity obtained by all transducers decreases with increasing RW content. These decreases are not influenced by the curing age of concretes. Decreases in the diameter and frequency of transducers caused reductions in ultrasonic velocity. These reductions are not influenced by the volume replacement of sand by RW. Correlations showed that ultrasonic velocity represents a reliable non-destructive technique for measuring the properties of rubberized concretes.
PL
W pracy przedstawiono badania zawartości chloru w betonie i proces korozji, w oparciu o pomiary oporu przewodnictwa elektrycznego i potencjału półogniwa próbek betonowych. Te analizy opierały się na doświadczalnych pomiarach próbek w funkcji czasu zanurzenia w 3,5% roztworze NaCl w wodzie, w temperaturze pokojowej, przez 18 miesięcy, zgodnie z europejskimi normami. Przygotowano mieszanki betonowe o różnym składzie, do których dodawano inhibitor, jakim był azotan wapnia i dwa rodzaje superplastyfikatorów. Wyniki doświadczeń pokazały, że po sześciu miesiącach zanurzenia próbki miały dużą zawartość jonów chlorkowych. Próbki C4 z dodatkiem 3% inhibitora i superplastyfikatora w formie Oxydtronu, jak również C3 z tym samym dodatkiem inhibitora i superplastyfikatora MAPEI Dynamon SR 31, wykazały dobrą odporność na korozję, w stosowanym roztworze NaCl. Znalazło to również potwierdzenie w serii pomiarów przewodnictwa elektrycznego i potencjału półogniwa, przeprowadzonych po doświadczalnym okresie 18 miesięcy.
EN
This work presents a study of the total chloride contents in concrete and the corrosion process by testing electrical resistivity and half-cell potential of concrete samples. The analysis was based on an experimental investigation of the samples with the time of immersion in 3.5% mass NaCl aqueous solution at room temperature for 18 months, according to European Standards. For this study, different mixtures of concrete were prepared by adding two types of superplasticizers and calcium nitrate inhibitor, in different concentrations. The results of the Cl- ions test showed that all the samples, after an immersion testing period of six months, contained high concentrations of Cl- ions. Samples C4 with 3% calcium nitrate inhibitor and Oxydtron superplasticizer as well as C3 with 3% calcium nitrate inhibitor and Mapei Dynamon SR 31 superplasticizer, showed good resistance to corrosion, in the tested environment. It was also proved by the results of several sets of measurements of the electrical resistivity and half-cell potentials carried on the concrete test samples, to the end of the 18 months testing period.
PL
W artykule o charakterze przeglądowym zaprezentowano potencjał mikrotomografii komputerowej, która może zostać zastosowana do badań i analiz strukturalnych materiałów drogowych takich jak mieszanki mineralno-asfaltowe. Praca zawiera opis metodologii badania z użyciem mikrotomografu komputerowego przeznaczonego do dokładnych badań materiałowych. Zaprezentowano ocenę strukturalną materiału, analizę porowatości oraz wykorzystanie obrazowania tomograficznego do oceny mechanistyczno-wytrzymałościowego materiału. Na przykładzie nowatorskiej analizy agresji chemicznej wywołanej agresją chlorkową przedstawiono dodatkowe możliwości techniczne urządzenia. Artykuł kończy podsumowanie opisanych zastosowań tej metody badawczej w stosunku do mieszanek mineralno-asfaltowych. Wskazano na zalety i możliwości wprowadzenia mikrotomografii do powszechnego użycia w drogowej inżynierii lądowej.
EN
The article shows the potential of computer microtomography that can be used for research and structural analysis of road materials such as asphalt mixtures. The work contains a description of the research methodology using a computer microtomograph on the example of asphalt concrete. The paper discusses the structural assessment of the material, porosity analysis, the use of tomographic imaging to assess the mechanics and strength of the material, and presents a novelty in the form of an analysis of chemical aggression caused by chloride aggression. The article ends with a summary of the applications of this research methodology in relation to asphalt mixtures and indicates the advantages and possibilities of introducing microtomography for widespread use in road engineering.
EN
The paper describes the impact and importance of preprocessing methods of fabric image for detection of inter-thread pores (ITP), which is a new method of individual ITP identification. The aim of this experiment is to identify precisely every individual ITP of fabric structure by using optimal preprocessing algorithm for further quantitative, morphometric structural analysis of specialized fabrics (barriers, industrial filters, composites, others) in context of air permeability, flow resistance, UV radiation, viruses penetration, thermal comfort by estimation fabric porosity, especially macroporosity parameters and cover factor. The correct identification of individual ITP depends on the acquisition method and the preprocessing algorithm. It was conducted by analyzing the adaptation of digital image preprocessing methods for two structures of plain weave fabric in two magnification zooms, 1.25 and 0.8. Preprocessing operations were performed in the area of spatial operations of the image. The optimal preprocessing algorithm includes low-pass filtering, histogram equalization, nonlinear filtering, thresholding, and morphological operation. This algorithm was selected based on the factors developed by the author (ITP detection, RID factor—a difference between the real and model ITP areas) which rely on the ITP size, shape, and location. The graphic view of the ITP contour position on the fabric image is a verification element in the optimal preprocessing algorithm. The presented results of the air permeability of two different plain weave structures confirm the need to optimize the algorithm of pre-image processing methods to precisely detect each individual ITP in the fabric image.
12
Content available remote Influence of Tensile Stress on Woven Compression Bandage Structure and Porosity
EN
Woven compression bandage (CB) is one of the elastic textiles that exert pressure on muscles. With a defined tensile strength, it is possible to create the required compression on the given body parts. This work aims to investigate the relationship between woven fabric deformation, porosity, and tensile stress properties of three main types of woven CBs. All bandage samples are applied on human leg using two- and three-layer bandaging techniques. Bandage porosity is calculated for all frames at different weave angles using NIS software. Woven bandage construction parameters which are given by the preparation of warp and weft yarns, twist, count, and density along with woven fabric weave, type of weaving, and finishing process are the main factors that influence the bandage properties. Several methods considering thread distributions have been developed to determine the woven fabric's porosity during the tensile stress. Experimental results confirm that bandage porosity is directly proportional to the bandage extension and weave angle that ranges from 44° to 90°. The novelty of candidate study is to introduce practical remarks to the patient for optimizing the required bandage pressure by suitable extension or applied tension or weave angle for two- and three-layer bandaging systems.
EN
Purpose: Purpose of this work is to analyse the process of synthesis of oxide ceramic coatings in plasma electrolytes on 2024 aluminium alloy and to form an electrolyte which allows to reduce energy consumption for the coating formation. Design/methodology/approach: The oxide ceramic coatings were synthesized on 2024 aluminium alloy. The coatings were formed by the alternate application of anode and cathode pulses to the sample. X-ray diffraction analysis of coatings was performed on a DRON-3.0 X-ray diffractometer using CuKa radiation. The thickness of the coatings was determined using a CHY TG-05 thickness gauge. The porosity of the coatings was investigated by analysing the micrographs of the plasma electrolyte oxidation (PEO) coatings obtained on a scanning electron microscope at x500 magnification using the image processing technique. Findings: The electrolyte with 5 g/l H2O2 additive have been elaborated as an optimal composition for synthesis of a coating with an increased content of corundum (a-Al2O3) as compared to a coating synthesized in the same mode in the 3KOH+2Na2SiO3 electrolyte without H2O2. This synthesis mode allows obtaining a coating with a high corundum content at low energy consumption. Research limitations/implications: For further optimization of the synthesis modes, it is necessary to analyse the influence of the phase composition and porosity of the obtained oxide ceramic coatings on their microhardness, wear resistance, and corrosion resistance. Practical implications: Based on the developed modes of synthesis of the coatings, it will be possible to obtain wear and corrosion resistant oxide ceramic coatings with predetermined functional properties and to reduce energy consumption for their formation. Originality/value: Methods for accelerating the formation of coatings have been proposed and tested, in particular, by adding various amounts of hydrogen peroxide to the electrolyte. The content of oxides in the obtained coatings, in particular, their ratios at various concentrations of hydrogen peroxide in the electrolyte, were determined by X-ray phase analysis. The modes of synthesis of the coatings were developed which allow obtaining a continuous coating without cracks with simultaneous decreasing porosity from 4.32% to 3.55-3.53%.
14
Content available On a formula finding fractal dimension
EN
Purpose: The article is devoted to the determination of the fractal dimension of cellular concrete, in particular foam concrete, and the further clarification of the relationship between fractal dimension and porosity and average density of cellular concrete. Design/methodology/approach: In the theoretical description of disordered systems, the fundamentals of fractal theory are actively used, which allow obtaining statistical indicators of chaotic natural and artificially disordered systems, which include cellular concrete. The parameters of the pore structure are difficult to quantify by conventional methods because of the complexity and irregularity of the pore structure due to their random distribution. Findings: Formulas for calculating the fractal dimension and average density of highly porous material are calculated and proposed. The formula for calculating the average density takes into account the density of the material between the pore walls. Research limitations/implications: The calculation of the fractal dimension is one of the main factors affecting the practical application of the theory of fractals, a natural problem arises on a theoretical basis to justify these calculations. Practical implications: The formulas proposed in this work for calculating the fractal dimension and density of a highly porous structure improve research on methods for producing substances with a controlled fractal structure, which will help create materials with unusual mechanical properties, density, and porosity. Originality/value: The formula for calculating the fractal dimension obtained in the work improves the well-known Hausdorff-Bezikovich formula. On the other hand, it makes it possible to obtain a highly porous structure with a given density of the material under study.
EN
Plates of AZ91 cast magnesium alloy with a thickness of 3.5 mm were butt-welded using a laser power of 2000 W and helium as the shielding gas. The effect of the welding speed on the weld cross-sectional geometry and porosity was determined by microscopic analysis. It was found that to avoid the formation of macropores, welding should be carried out at a speed of 3.4 m/min or higher. Non-equilibrium solidification of the laser-melted metal causes fragmentation of the weld microstructure. Joints that were welded at optimal laser processing parameters were subjected to structural observations using optical and scanning microscopy and to mechanical tests. The mechanical properties were determined through Vickers hardness measurements in the joint cross-section and through tensile testing. The results indicate that the hardness in the fusion zone was about 20 HV (30%) higher than that of the base material. The weld proved to be a mechanically stable part of the joint; all the tensile-tested specimens fractured outside the fusion zone.
EN
At nanoscale, surface free energies of the atoms located on the free surfaces of structures significantly affect their mechanical characteristics. In this study, nonlinear large-amplitude free vibration response of nanoshells prepared from functionally graded porous materials (FGPM) is investigated by taking into account surface stress size effects and vibrational mode interactions. Non-classical shell model is constructed on the basis of the Gurtin–Murdoch type of the surface theory of elasticity having the capability of capturing surface stress size dependency. The accuracy of nonlinear vibration analysis is improved by incorporating the interaction of the main vibration mode and the first, third and fifth symmetric oscillation modes. Moreover, the closed-cell Gaussian-Random field scheme is put to use to extract the mechanical characteristics of FGPM nanoshell. Multiple timescales technique is then applied to achieve surface stress elastic-based nonlinear frequency of FGPM nanoshell analytically for different interactions between vibrational modes. It is revealed that by incorporating the interactions of the main vibration mode and higher symmetric oscillation modes, the behavior of the backbone curves belongs to the nonlinear free oscillation response of FGPM nanoshells changes from hardening to softening schema. It is found that when only the main vibration mode is taken into account, surface elasticity effects makes an enhancement in the significance of the hardening schema. However, by considering the interactions of higher symmetric oscillation modes, surface elasticity effects makes a reduction in the significance of the softening schema.
17
Content available remote Research of 316L metallic powder for use in SLM 3D printing
EN
3D metal printing is an increasingly popular production of steel parts. The most widespread and most accurate method is SLM (Selective Laser Melting), which uses metallic powder as the input material. The article is dedicated to researching the supplied powder from Renishaw. The powder is made by gas atomization and 3 phases of powder (virgin, sift and waste) that are present in the SLM process are examined. Powder morphology by SEM electron microscopy is investigated and the porosity of the powder is measured by optical method. Next, the powder grain size fraction is examined. In conclusion, there are recommendations and other directions of possible research. The main quantitative result from research is that, in general, small particles are reduced in the sift powder and the number of larger particles is increased, but the powder is still usable for further use.
EN
The Al2O3+TiO2 coatings are of the interest of surface engineering due to their high hardness and wear resistance but also increased toughness, when compared to pure Al2O3 ones. This article describes the deposition of Al2O3+3 wt.% TiO2 coatings by Atmospheric Plasma Spraying (APS) technique. The commercial AMI 6300.1 powder (-45 + 22 μm) was used as a feedstock. The 2k+1 spraying experiment, based on two variables, namely spray distance and torch velocity, was designed. The samples were characterized in the terms of morphology, microstructure, microhardness and roughness. It was observed that the shorter spray distance resulted in lower porosity, higher microhardness and lower roughness of coatings.
PL
Powłoki Al2O3+TiO cieszą się zainteresowaniem inżynierii powierzchni ze względu na wysoką twardość i odporność na zużycie ścierne przy jednocześnie zwiększonej odporności na kruche pękanie, w porównaniu z powłokami na bazie czystego Al2O3. W artykule opisano proces natryskiwania powłok Al2O3+3% wag. TiO2 metodą proszkowego natryskiwania plazmowego (APS). Jako materiał wsadowy wykorzystano komercyjnie dostępny proszek AMI 6300.1 (-45+22 μm). Zaprojektowano plan eksperymentu 2k+1, oparty na dwóch zmiennych - odległości natryskiwania i prędkości przesuwu palnika względem podłoża. Próbki charakteryzowano pod względem morfologii, mikrostruktury, mikrotwardości oraz chropowatości. Zaobserwowano, że zmniejszenie odległości natryskiwania pozwala uzyskać powłoki o mniejszej porowatości, większej twardości i niższej chropowatości.
EN
Atmospheric Plasma Spraying (APS) enables deposition of coatings from different materials, including those based on Al2O3 and TiO2. In this work, Al2O3 + 40 wt.% TiO2 coatings were tested. The relationships between mechanical properties, microstructure and spraying parameters (namely: spraying distance and torch scan velocity) were investigated. Commercial -45 + 5 μm powders in agglomerated as-produced state were sprayed onto the stainless steel 1.4301 substrates. The aim of the study was to determine the adhesion, microhardness and roughness of coatings but also to characterize their microstructure. It was observed that coatings sprayed from shorter distance were well melted and revealed good adhesion, but at the same time they were more porous and of lower microhardness than those deposited from the longer spraying distance.
PL
Metoda natryskiwania plazmowego, APS (ang. Atmospheric Plasma Spraying) umożliwia nanoszenie powłok z różnych materiałów, w tym na bazie Al2O3 oraz TiO2. W pracy zbadano powłoki Al2O3 + 40% wag. TiO2. Przedmiotem badań były właściwości mechaniczne oraz mikrostruktura uzyskanych powłok, w zależności od odległości natryskiwania i prędkości przesuwu palnika względem podłoża. Wykorzystano komercyjne proszki w stanie aglomerowanym o granulacji -45 + 5 μm, którymi pokryto podłoża ze stali nierdzewnej 1.4301. Przeprowadzone badania miały na celu określenie przyczepności powłok, ich mikrotwardości, chropowatości oraz charakteryzację mikrostruktury. Zaobserwowano, że krótsza odległość natryskiwania skutkuje wyższym stopniem przetopienia cząsteczek proszku w powłoce oraz wyższą przyczepnością powłok, ale jednocześnie powoduje wyższą porowatość i niższą mikrotwardość powłok.
PL
Wykonano badania nad możliwościami zwiększenia przepuszczalności powietrza papierów przeznaczonych do wytwarzania worków. Porównano skuteczność stosowanej obecnie metody poprawy tego parametru poprzez perforowanie struktury materiału na sucho z nową metodą polegającą na wykonaniu tej operacji wówczas, gdy wstęga papieru jest jeszcze w stanie mokrym. Na podstawie otrzymanych wyników stwierdzono, iż zaproponowana metoda umożliwiła utrzymanie akceptowalnego kompromisu pomiędzy przyrostem przepuszczalności powietrza wytworów papierniczych oraz niewielką utratą ich parametrów wytrzymałościowych (w odniesieniu do efektów uzyskiwanych drogą perforacji na sucho).
EN
Research works related to the problem of the improvement of air permeability for sack papers were conducted. Comparison of the effectiveness of currently used method based on the puncturing of dry paper with newly proposed method was done. New method is based on the puncturing of paper which is still in wet state. Obtained results show that proposed method allows to maintain the acceptable compromise between obtained high air permeability and acceptable decrease in strength properties of the processed paper.
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