Development of double screw press and method of controlling the parameters of the briquetting process

Paper is focused on development of new patented construction of screw briquetting machine for compacting biomass into the solid biofuel. Developed machine design is based on achieved results of comprehensive research of the complicated process of biomass densification. Patented construction provides two main goals: the elimination of axial forces, which causes increasing of bearings lifetime, and a new modular design of pressing chamber and tools with geometry based on application of the mathematical model. Research of the biomass densification pointed to the need for modular design of densification machine, where it is possible to control all significant parameters of the densification process. The goal of this paper is to present a new patented design of screw press, which satisfies all requirements for modularity and control of the parameters. It allows optimizing this process for different types of raw materials and achieving high quality production. Results of experimental research of densification process then allow the engineering design of the production machine tailor-made to the customer, while being able to minimize investment, energy and operating costs. The developed design of screw press is unique in its modularity and high reliability.

Influence of the sintering temperature on the microstructure, mechanical properties and densification characteristics of (TiB+TiC)/TC4 composite

A hybrid of TiB whiskers and TiC particles reinforced TC4 matrix composites were in-situ synthesized by spark plasma sintering (SPS) using a TC4-0.6wt.% B4C powder mixture at temperatures range from 550°C to 1150°C. The effect of sintering temperature on microstructure, grain size, mechanical properties and densification process of the (TiB+TiC)/ TC4 matrix composites were investigated. The composite sintered at 1050℃ has the highest tensile strength (1129.0 MPa), yield strength (1077.8MPa) and plasticity (7.1%). The aspect ratio of TiB whiskers increases almost linearly below 1050°C and its highest value is 33.2. The grain size of TiC increases with the increase of sintering temperature, and rapid growth occurs in the range of 850°C to 950°C. The composite sintered body appears four shrinkage stages before applying sintering pressure. The corresponding peak temperatures are 663℃, 758℃, 840℃ and 994℃, respectively.

Conjunction of gallium doping and calcium silicate mediates osteoblastic and osteoclastic performances of tricalcium phosphate bioceramics

Gallium-containing biomaterials are considered promising for reconstructing osteoporotic bone defects, owing to the potent effect of gallium on restraining osteoclast activities. Nevertheless, the gallium-containing biomaterials were demonstrated to disturb the osteoblast activities. In this study, tricalcium phosphate (TCP) bioceramics were modified by gallium doping in conjunction with incorporation of calcium silicate (CS). The results indicated that the incorporation of CS promoted transition of β-TCP to α-TCP, and accelerated densification process, but did not improve the mechanical strength of bioceramics. The silicon released from the composite bioceramics diminished the inhibition effect of released gallium on osteoblast activities, and maintained its effect on restraining osteoclast activities. The TCP-based bioceramics doped with 2.5 mol% gallium and incorporated with 10 mol% CS are considered suitable for treating the bone defects in the osteoporotic environment.

Investigate The Sintering Behavior of IZO Ceramic Targets Prepared By Pressure Slip Casting

The density and phase structure uniformity of the IZO ceramic target would have an effect on the optoelectronic properties of the sputtered film. In this work, a uniformly dispersed IZO slurry was used to obtain high-density green IZO compacts by the slip casting process. Based on the grain size and shrinkage data of IZO ceramics, the densification process was investigated, while the apparent activation energy and growth activation energy were also calculated. The results of XPS showed that sintering in an oxygen atmosphere can increase the concentration of oxygen vacancies of IZO ceramic to improve its electrical properties. Finally, IZO ceramics with a grain size of 3-6 μm and resistivity of 1.5 mΩ·cm were obtained by a two-step sintering method.

Master sintering curve of W-Mo-Cu alloy prepared by electric field sintering

The master sintering curve (MSC) was developed for the densification description and prediction of W-Mo-Cu alloy sintered by lager current electric field sintering. W-Mo-Cu compacts were sintered at the temperature of 975°C, pressure of 30MPa, and heating rate of 25,75,125°C/s, respectively. The MSC of W-Mo-Cu alloy was successfully constructed with the calculated value Q = 110kJ/mol and experimental data (such as shrinkage data and sintering time and temperature) of the compact. The shrinkage response and the densification process of the compact were studied with the MSC. What's more, the densification of the alloy was verified and predicted by the MSC. The results show that the MSC is a promising strategy for predicting the densification evolution of ternary alloy during sintering.

Densification of Biocarbon and Its Effect on CO2 Reactivity

Charcoal is an interesting reducing agent because it is produced from biomass which is renewable and does not contribute to global warming, provided that there is a balance between the felling of timber and growth of trees. Biocarbon is a promising alternative to fossil reductants for reducing greenhouse gas emissions and increasing sustainability of the metallurgical industry. In comparison to conventional reductants (i.e., petroleum coke, coal and metallurgical coke), charcoal has a low density, low mechanical properties and high CO2 reactivity, which are undesirable in ferroalloy production. Densification is an efficient way to upgrade biocarbon and improve its undesirable properties. In this study, the deposition of carbon from methane on three types of charcoal has been investigated at 1100 °C. CO2 reactivity, porosity and density of untreated and densified charcoal were measured, and results were compared to metallurgical coke. Surface morphology of the charcoal samples was investigated by using scanning electron microscopy (SEM). SEM confirmed the presence of a deposited carbon layer on the charcoal. It was found that the CO2 reactivity and porosity of charcoals decreased during the densification process, approaching that of fossil fuel reductants. However, the CO2 reactivity kept higher than that of metallurgical coke.

How to evaluate densification? Case study of Lourdes neighborhood, Santiago, Chile

Purpose This study aims to question the fact that density has been considered only as an instrument of calculation to be used on regulation mechanisms, without taking into consideration other variables related to density. The paper proposes a framework consisting of four determining factors for urban analysis that have to be considered before starting a densification process: connectivity and permeability of network, mixture of uses, relation to urban morphology and public spaces for each district. The methodological analysis was carried out for the case of the district of Gruta de Lourdes, Quinta Normal, located in northwest Santiago, which has started a densification process the recent years. Design/methodology/approach The present discussion aims to obtain objective parameters to determine if urban development allows livability and a balanced relationship with actual urban form and diversity. There appear to be four determining factors of urban analysis: connectivity and network permeability, the mixture of uses, public spaces and urban form development. The district of Gruta de Lourdes will be used to delve into these parameters to place the debate around density in objective terms. To look in depth at each of the criteria for evaluating densification processes, various methods were selected for quantifying the observed variables: to evaluate connectivity and integration of a neighborhood with the rest of the city, the spatial configuration analysis “Space Syntax” will be used; to evaluate mix of uses, mixed-use index, or ratio of non-residential use will be used; urban morphology, plot size, housing density (dw/ha), lot coverage and floor area ratio will be used; public spaces, the percentage dedicated to each of these in m2/inhab. Findings The results allow us to conclude that it is necessary to plan densification processes via an analysis that promotes connectivity, mixture of uses, urban morphology and the available public spaces to understand density as a multivariable phenomenon. In addition, we conclude that the case study district, Gruta de Lourdes, can withstand greater demand for housing as long as the context is taken into account. A possible option to asset the densification potential could be the “infill” strategy, which aims to be a type of intervention that does not change the structure of the neighborhood as new buildings are positioned among existing ones, maintaining the form of the streets and the structure of plot divisions. Originality/value The value of the paper is to contribute to the discussion on how to renovate central areas in Latin American cities looking at variables such as connectivity, mixture of uses, urban morphology and public spaces, which are directly related to density. Moreover, the paper contributes to discuss new ways to analyze and measure densification, toward planning a district’s renovation. In addition, the quantitative methodological approach to the densification processes gives a new understanding of how to determine density. Finally, the paper reveals an opportunity to rethink the inner city toward new approaches to renovation developments.