Densification Technology Research Articles

Study on the Resistance of Concrete to High-Concentration Sulfate Attack: A Case Study in Jinyan Bridge.

Concrete structures face significant challenges in sulfate-rich environments, where sulfate attack can affect their durability and structural integrity. This study explores innovative approaches to enhancing concrete performance by integrating hydrophobic and densification technologies. It emphasizes the critical role of anti-sulfate erosion inhibitors in mitigating sulfate-induced damage, reducing water absorption, and inhibiting corrosive reactions. This research addresses prevalent issues in Chinese engineering projects where high sulfate concentrations are common, necessitating robust solutions for sulfate resistance. Through rigorous testing, including wet-dry cycling tests with 5% and 10% Na2SO4 solutions following the GB/T 50082-2009 standard, concrete formulations achieved exceptional long-term sulfate resistance, meeting or exceeding KS200-grade requirements. These findings provide valuable insights into optimizing concrete durability in sulfate-rich environments, offering practical strategies to enhance infrastructure resilience and reduce maintenance costs.

Briquette Production from Vineyard Winter Pruning Using Two Different Approaches

Worldwide, different strategies are being developed in order to ensure optimum conditions for the development and growth of economic competitiveness, as well as for increasing the quality of life and environmental protection. All these strategies are closely linked to the development and modernization of systems for producing energy from clean and renewable sources. In this context, the present paper presents the results of research regarding the evaluation of the sustainability of briquette production using biomass resulting from vine winter pruning as the raw material. An analysis of the scientific literature indicates that nearly 8 Mt of biomass would result from the over 7.4 million hectares of vine plantations in the world, biomass that could be valorized through densification in order to produce solid biofuels with a lower calorific value of more than 17 MJ/kg. This study examines the production of briquettes from vineyard winter pruning with consideration of two types of densification technologies: baling and natural drying of the tendrils, and collection, shredding, and artificial drying of the lignocellulose debris. The quality indices and energy consumption and energy efficiency of the briquettes were evaluated to determine their feasibility as an alternative fuel source. When designing the scientific endeavor, the following aspects were considered: defining the aim and objectives of the research; designing the research algorithm; collecting, preparing, and conditioning the biomass; conducting a chemical analysis of the briquettes; and evaluating the energy consumption and energy efficiency for producing the briquettes, taking into account two drying methods (natural and artificial drying). In the meantime, some specific laboratory equipment was designed and built for the artificial drying of biomass, evaluation of mechanical durability, measurement of energy consumption, etc. Analysis of the experimental data has led to the conclusion that the agricultural waste from vine pruning can constitute an important and sustainable source of energy in the form of briquettes that fulfill most of the requirements imposed by international standards.

Effect of densification technology on the microstructure and mechanical properties of high-entropy (Ti, Zr, Hf, Nb, Ta)C ceramic-based cermets

High-entropy ceramic-based cermets represent a new and promising direction in improving the mechanical properties of conventional hardmetals through the formation of complex microstructures during synthesis. This has been systematically studied in two Co-free, high-entropy (Ti,Zr,Hf,Nb,Ta)C ceramic-based cermets using 10 wt% Ni and 10 wt% FeCrAl metallic binders during hot-press and spark plasma sintering. Fully densified microstructures were achieved in the temperature range of 1400–1500 °C, which is below the melting points of the pure Ni and FeCrAl alloy, owing to the liquid-phase assisted sintering. The optimal densification routes resulted in Vickers hardness (HV30) of 16.77 ± 0.72 and 18.32 ± 0.99 GPa, and fracture toughness (KIc_SENB) of 5.31 ± 0.41 and 4.83 ± 0.50 MPa m0.5, respectively for the Ni and FeCrAl bonded cermets. The improved damage tolerance of these cermets compared to the base (Ti,Zr,Hf,Nb,Ta)C high-entropy carbide is related to the reduced grain size and microstructural toughening mechanisms (e.g. crack deflection and bridging).

Rapid prediction of water hammer characteristics in liquid hydrogen storage and transportation systems: A theoretical model

A renewable energy liquid hydrogen storage and transportation system is a very complex system, so water hammering due to valve closure cannot be ignored. A theoretical model for the rapid prediction of the water hammer effect in liquid hydrogen pipeline valves was developed in this work. The impact of valve closure characteristics and subcooling on the peak pressure water hammer was analyzed. The results indicate that as the subcooling temperature of liquid hydrogen decreases, the density of subcooled liquid hydrogen increases, leading to larger peak pressures in the water hammer transient. At subcooling temperatures of 14, 16, 18, and 20 K, the maximum instantaneous pressures for the water hammer fluctuation are 51563.02, 50846.76, 50082.40, and 48510.70 Pa, respectively. Under identical boundary conditions, the density of subcooled liquid hydrogen emerges as the primary factor influencing the peak pressure of water hammer. The theoretical model exhibits a significant advantage in terms of computational time cost, saving approximately 9.99 h. However, the accuracy of the theoretical model is slightly inferior to that of the CFD model. The results of the study are expected to provide a technical basis for the design of refueling systems for storage and transportation, as well as densification technology of supercooled renewable liquid hydrogen and safety protection.

Dual-Cation CuAgSe-Based Material: Rapid Mass Transfer in Synthesis and High Thermoelectric Performance Realization.

Understanding mass transfer mechanisms is vital for developing new material synthesis and densification technologies. Ion transport, serving both mass and charge transfer, is essential for the rapid preparation of high-performance fast ionic conductor thermoelectric materials like Zn4Sb3 and Cu2Q (Q = S, Se). In the case of dual-cation fast ion conductor materials like CuAgSe, exploring the relationship between cation transport becomes pertinent. In this study, copper (Cu) and selenium (Se) undergo a reaction in the presence of an electric field (∼15 A), resulting in the formation of the CuSe compound. Subsequent to this initial reaction, a subsequent thermal environment facilitates the interaction among Cu, CuSe, and Ag2Se, culminating in the rapid formation and densification of CuAgSe (with a relative density exceeding 99%) in just 30 s. Evidently, the diffusion of copper ions substantiates a pivotal role in facilitating mass transfer. As a result, CuAg1+xSe samples with different silver contents (x = 0.01, 0.02, 0.03, 0.04 and 0.05) can effectively inhibit cation vacancy, and introduce highly ordered Ag nanotwins to enhance the electrical transport performance. For CuAg1.04Se, a peak ZT value of 1.0 can be achieved at 673 K, which is comparable to the literatures. This work will guide the future electric field-assisted rapid mass transfer of materials.

Progress towards the standardization of test parameters and protocols for evaluating densified fuel products

Densification technologies used in managing biomass and coal fines to produce fuel briquettes or pellets are gaining rapid acceptance and application due to the widespread uptake of renewable energy. This has resulted in the mushrooming of many standard and non-standard evaluation tests for densified solid fuels in this industry. These tests are sometimes inconsistently applied especially if the available options for evaluation, underlying assumptions and principles of the test methods chosen are misunderstood. A critical review of the fuel briquettes evaluation tests to understand their relevance, strengths and limitations is necessary to advance public and research knowledge. This study investigated current methods of standardization to identify best practices, inconsistencies, trends and gaps in the application of fuel briquettes testing protocols. Procedures for evaluating combustion or thermal properties include calorific value, burn rate, open air combustion test and water boiling test; ignition time; after-glow test; specific fuel combustion or thermal efficiency were discussed. Physical and chemical property evaluations involved densities and related ratios, proximate and ultimate analyses. Equally important are mechanical parameters frequently informed by tensile/compressive strength, impact resistance, friability and water resistance. As renewable densified fuels gain more global popularity, it is critical to have a uniform standard of evaluating their quality.

A review of the combined torrefaction and densification technology as a source of renewable energy

Densification techniques allow biomass to be used in the energy mix with coal or as a direct replacement for coal as it is a renewable resource. Typically, biomass is bulky, so thermochemical methods, like torrefaction, reduce volatiles and moisture, leaving a higher composition of fixed carbon. After the torrefaction process, the torrefied biomass poses problems during handling, transportation, and storage because it consists of small (<100 μm) disintegrated particles. Densification minimizes these problems through thermal compaction which produces integrated and larger (4 mm – 200 mm diameter) solid particles. This process can be done naturally (without any additives) or by adding binders which improve the torrefied biomass’s physical, chemical, mechanical, and heating properties. This in turn reduces any costs associated with handling/transportation and storage of the biomass before it is used for energy generation. Densification increases the biomass’s energy content per unit volume thereby enabling coal substitution. Recent reviews on densification have mainly focused on the binding of coal fines, raw biomass, and some torrefied biomass. Reviews on the binding theories are also available. This current review focuses solely on the aspect of torrefied biomass densification and the factors associated with the process. Insights and recommendations for the possible application of an integrated biomass torrefaction and densification process were provided herein. In addition, the gaps in literature were identified to enable future research on the application of the process to realize innovative renewable energy production in industry.

Short Review of Flash Sintering: Mechanisms, Microstructures, and Mechanical Properties

This review article highlights the potential of flash sintering as a novel densification technology for advanced ceramics. Conventional ceramic sintering methods involve heating a powder compact at high temperatures for several hours to trigger the solid-state diffusion of atoms. In contrast, flash sintering takes advantage of electric field and current to drastically lower processing time and temperature, providing a promising solution to reduce the economic, energetic, and environmental costs associated with traditional ceramic sintering methods. The effects of electric field and current during flash sintering result in unique non-equilibrium microstructures that enhance the mechanical properties of advanced ceramics through defect-mediated inelastic deformation mechanisms. This article provides an overview of the flash sintering mechanisms, the unique microstructural features observed in flash-sintered ceramics, and their impacts on mechanical properties.

Resource efficiency and energy efficiency (REEE) in the Portuguese ceramic industry: Towards net zero carbon production

The Portuguese ceramic industry constitutes 0.5% of Gross Domestic Product in Portugal, far higher than most other European nations, and thus it is essential this sector is decarbonised, cost-effectively to preserve jobs and national revenue. Moreover, the small size of the country and the co-location of ceramic factories dominantly in northern Portugal lowers the logistical barriers to act collectively to form networks and engage in collective strategies to push towards net zero carbon production. This article considers Portugal as an ideal case study for strategic and collective action to develop and facilitate carbon mitigation strategies. The article focusses mainly on current and future resource efficiency and energy efficiency strategies but additionally assesses the role of fuel switching (H2 vs electrification) and low energy densification technologies.

Physical and Morphological Changes in Heat-Treated and Densified Fast-Growing Timber Material

Heat treatment is a modification method that can alter the polymeric components of wood (cellulose, hemicellulose and lignin). Densification technology has emerged as one of the promising technologies capable of improving the properties of low-density wood. In this study, the effects of heat treatment and densification on moisture content, density, and morphological features of low-density Paraserianthes falcataria laminas were examined. Laminas were heat-treated (100°C, 120°C and 140°C for 1 hour) and compressed at 50% compression ratio. Non-heat-treated laminas, on the other hand, were compressed at 40-60% compression ratios. The changes in pores area, moisture content and density of the heat-treated and densified laminas were identified. The lowest moisture content for heat-treated laminas was at 120°C. Laminas with 60% compression ratio were observed to have the highest deformed pores, where it increased the density of the laminas. In summary, heat treatment and densification affected the properties of the laminas. Heat treatment at high temperatures resulted in decreased density and moisture content, while increasing the compression ratio during densification increased the density. The results suggest that combining heat treatment and densification could be a viable method for improving the properties of low-density wood.

Influence of Densification Treatment on The Morphology and Density Profile of Paraserianthes falcataria Laminas

Fast-growing wood species have a limited range of applications due to their low density. Despite that, densification technology can be applied to improve its density. In this study, laminas from Paraserianthes falcataria, a low-density wood species, were subjected to viscoelastic- thermal compression (VTC), a densification treatment. The objective of this study was to evaluate the impact of different pre-steaming durations in the densification treatment on the cell lumen deformation and density profile of Paraserianthes falcataria laminas. The laminas were pre-steamed with different durations ranging from 0–30 min, compressed with heat, and cooled down. For cell lumen area measurement, laminas pre-steamed for 30 min had the lowest cell lumen area, where the decrease in the lumens contributed to an enhancement in density. The finding from the density profile measurement indicated that densification treatment had enhanced the density of the laminas by up to 50%, whereby laminas pre-steamed for 10 min achieved the highest density.

Multi-physical modeling and numerical simulation of the thermo-hygro-mechanical treatment of wood

The contribution at hand introduces computational modeling and realistic simulation concepts for a comprehensive description of the manufacturing and application of densified wood and wooden structures made from molded densified wood. Wood, as a natural material, is characterized by e.g. a very good mechanical load-bearing capacity related to its density. Nevertheless, the ratio between its mechanical properties and its density can be optimized by densification technology for an expanded use of wood in structural engineering. The wood densification process is not only a mechanical process with large and irreversible deformations, it is also denoted by temperature- and moisture-dependent treatments of the wooden specimens. Thus, the introduced approaches to predict the material and structural characteristics of compressed and molded wood consist of an inelastic and multi-physical constitutive modeling of wood at finite deformations as well as the computation of effective structural properties of wood after the thermo-hygro-mechanical densification process. A successful implementation of the modeling concepts into the finite element method (FEM) is presented, which is verified by numerical investigations. A validation of the numerical results is carried out by use of experimental data at beech wood (Fagus Sylvatica, L.), taken from literature.

Integrated Life Cycle Assessment Modelling of Densified Fuel Production from Various Biomass Species

This work presents new data on the life cycle impact assessment of various lignocellulosic biomass types in Mexico. A comparative life cycle assessment model of biomass densification systems was conducted. An integrated approach that incorporated various process variables, such as technology and variations in feed properties, within the analysis was employed to evaluate the environmental impact of producing 1 MJ of energy-containing densified fuel. The results show that the densification unit and curing (fuel drying) have the highest impact on the life cycle’s operational energy and the total life cycle energy, respectively. Of all the 33 biomass types from the 17 species sources considered in this study, sweet sorghum and sandbur grass have the highest global warming potential, 0.26 and 0.24 (kg CO2-eq), and human toxicity 0.58 and 0.53 (kg 1,4-dichlorobenzene-eq), respectively, while coffee pulp and cooperi pine wood have the least impact in both categories, with values of 0.08 and 0.09 (kg CO2-eq), and 0.17 and 0.16 (kg 1,4-dichlorobenzene-eq), respectively. Chichicaxtla sawmill slabs also have a low environmental impact, and cooperi pine and Ceiba wood have the lowest ozone depletion and ecotoxicity potential. A sensitivity analysis indicated the effects of the transportation system and energy source on the life cycle’s environmental impact. Adequate feed preparation, the blending of multiple feeds in the optimum ratio, and the careful selection of densification technology could improve the environmental performance of densifying some of the low-bulk-density feed biomass types.

A review on various types of densification/briquetting technologies of biomass residues

The growing development, industrialization and population is the main reason of the increment in the global power demand around the world. The conventional power resources are limited and not eco-friendly as well as diminished in the future. Now, every country is move towards the more utilization of renewable energy resources. The biomass renewable energy source is one of them. The biomass residues material can be utilized for the production of power and also overcome the problem of decomposition of agricultural wastes and other wastes products by conversion into solid biomass fuels. The conversion of scattered agricultural residues/wastes into the useful product (biomass fuel) through the technology known as densification. The densification process supports the more utilization of renewable source and clean energy demands. The environmental challenges related with burning of biomass residues in the open field can be minimized by the densification of biomass residues. The densification is the process of compaction or densifying the biomass residues or waste through the application of various pressure levels. The challenges associated with handling, storage and transportation of biomass residues can also be minimize by densification technology. Briquettes and pellets are the end product of densification applications. The various types of densification pressure application and comparison have been discussed in the paper.

Ultrasonic modification for improvement of wood-Surface properties

This study evaluated the effect of ultrasonic densification technology on the surface hardness of the following wood species: aspen (Populus tremula), Scots pine (Pinus sylvestris) linden (Tilia europaea), alder (Alnus glutinosa), and oak (Quercus robur). The machine realising the proposed technology consists of an ultrasonic module and an infeed system that allows the treatment of sawn timber. The densification was achieved by feeding sawn timber specimens once through a pair of opposing ultrasonic sonotrodes, with the gap between them being smaller than the specimen thickness. This and the direct contact between the sonotrodes and the specimens led to an increase in density in the surface region and an increase in surface hardness, measured by the Leeb method. The internal structure was not damaged by the ultrasonic treatment. The simplicity of the process and the processing speed of several meters per minute merit further investigations of the technology.

Mechanical properties of compressed wood

Wood is a natural composite material. One the strength of wood is its good ratio of mechanical properties with respect to density, which can be further improved by densification technology. Compressed Wood (CW), with superior mechanical properties, could be utilised in timber products and timber connections as an alternative to energy-intensive adhesives and metals. However, the limited literature available on the mechanical properties of CW makes it chanllenging to utilise them in the development of new products and structures. To address this issue, this paper presents a comprehensive test programme and an extensive database of CW materials. It includes experimental results of over 720 material tests that were conducted on CW materials. The fundamental tests under compression, tension, bending, embedment, yield moment, shear and impact tests were undertaken. The results obtained from this study will help engineers utilise more CW to develop new products and connections. The results are also compared with the characteristic values of solid wood from the literature. As the densification of wood significantly improves strength and stiffness, this work will contribute towards the substantial uptake of CW in the building and construction industry with great benefits to the environment.

Characteristic Study of Briquette Cyanobacteria as Fuel in Chemical Looping Combustion with Hematite as Oxygen Carrier

Due to the more and more serious cyanobacteria bloom problem, it is particularly urgent to find a technology suitable for large-scale disposal and the efficient recovery of abundant nitrogen and phosphorus resources in cyanobacteria. The combination of chemical looping combustion (CLC) and biomass densification technology is thought to be a promising utilization selection. Based on the experimental results, the mechanical strength and energy density of briquette cyanobacteria are evidently increased with the compressive load; whereas, 10% is the optimal moisture content in the densification process. A higher heating rate in TGA would result in the damage of the internal structure of the briquette cyanobacteria, which are conducive to the carbon conversion efficiency. The presence of a hematite oxygen carrier would enhance the carbon conversion and catalyzed crack liquid products. CO2 yield is increased 25 percent and CH4 yield is decreased 50 percent at 900 °C in the CLC process. In addition, the lower temperature and reduction atmosphere in CLC would result in a lower NO emission concentration. The reactivity and porous property of hematite OC in CLC also increased during 10 redox cycle experiments. The CLC process accelerates the generation of CaH2P2O7 and CaHPO4 in cyanobacteria ash, which is more conducive to phosphorus recovery.

Escalation quality of wooden beams as building construction with densification technology

In this research has done the densification process of jabon wood and its measuring 5/7 cm into 5/5 cm by heat compression. The research objective determines the reliability of wood densification technology as improving the physical and mechanical wood properties. This research also used U steel as a tool press. The results showed that densification in jabon wood can improve its physical properties as indicated by the increase in specific gravity amounted to 28.95 percent; its density increased 26.83 percent; as well as water content declined of 32.68 percent. The mechanical properties of jabon wood shown by parameters like the strength perpendicular to fiber increased to 51.44 percent; MOE increased to 32.93 percent, and MOR increased to 36.14 percent. Treatment of densification on jabon wood has increased the strong class of jabon wood from strength class IV into a strength class III based on specific gravity and value of MOR rise to strength class II. Densified jabon wood is suitable for use as building construction materials and gives its aesthetic value because its color is more attractive. The architectural design of urban buildings can also use the densified wood material as it proves to

In-situ penetration of ionic liquids during surface densification of Scots pine

Abstract The moisture-induced recovery of compressed wood is one of the major problems of wood densification technology. Achieving a cost-efficient surface densification process without the need for additional resins to eliminate the set-recovery may lead to an increase in value of low-density wood species. A previous study has shown that a pre-treatment with ionic liquids (ILs) can nearly eliminate the set-recovery. It was however observed that during the pre-treatment process the IL did not penetrate sufficiently deep into the wood to explain the achieved reduction in set-recovery. Based on these findings, the hypothesis was posed that further penetration of the IL into the wood occurs during the densification stage as a consequence of the applied heat and pressure. Thermo-gravimetric analysis (TGA) and gas-chromatography mass-selective-detection (GC-MSD) showed that the depth of penetration of the IL was greater after the densification process than before. Digital image correlation (DIC) showed that in regions with a high IL concentration, there was almost no set-recovery, and it gradually increased with a decrease in the IL concentration, as observed with TGA and GC-MSD analysis.

High Volumetric Energy Density of LiFePO4 Battery Based on Ultrasonic Vibration Combined with Thermal Drying Process

Increasing the compaction density of electrodes is an effective way to increase the volumetric energy density of the full battery. To avoid the problem of low compaction density, material breakage, and porosity decrease during the process of calendering, which greatly deteriorate the electrochemical performance of the battery, in this paper, for the first time, we use ultrasonic vibration-assisted densification technology combining with thermal drying technology to prepare the electrodes. Ultrasonic vibration reduces the friction among the powder particles during the drying process, so that the particles of active materials could aggregate more closely. And then, there are smaller displacements and sliding during the calendering process in ultrasonic vibration-assisted (UV–A) electrode than ordinary ones, which not only avoid the failure of the binder and the shedding of the carbon layer, also increase the number of connection points between material particles. The results show that the UV–A densification technology leads to improved volumetric energy density (increased by 5.3%, 6.6%, 7.6%, 11.6%, 13.4%, and 13.0% compared to the ordinary battery at 0.2C, 0.5C, 1C, 2C, 5C, and 10C, respectively), cycle performance and ion conductivity of full battery.