Softening Development Research Articles

Development of softening and melting testing conditions simulating blast furnace operation with hydrogen injection

ABSTRACT Softening and Melting (S&M) experiments have evolved alongside the blast furnace as a crucial tool for burden characterisation and optimisation. Modern blast furnaces derive a base load of hydrogen from various sources. However, with hydrogen-enrichment of the blast furnace being considered to mitigate emissions, new S&M test conditions are required. In this study, a 2-D axisymmetric CFD model is used to simulate the internal conditions of a modern blast furnace operation, and a future operation with tuyere level hydrogen injection. The model results are used to guide the development of novel S&M test conditions, inclusive of H2, H2O, CO, CO2 and N2. The maximum hydrogen concentration under hydrogen enrichment was 20%, with the hydrogenous fraction of the gas primarily replacing nitrogen. A particular focus was given to the importance of including water vapour in the inlet gas, andits impact on reactions occurring in the S&M test.

Development of softening and ballasted flocculation as a pretreatment process for seawater desalination through a reverse osmosis membrane

Efficient desalination through a reverse osmosis (RO) membrane requires the prior removal of blockade-causing substances from raw seawater. To achieve ultrahigh-speed processing of a pretreatment process for seawater RO desalination, we combine traditional softening with ballasted flocculation (SBF) for Ca2+ and Mg2+ removal. An alkaline mixture of Ca(OH)2 and Na2CO3 was the most suitable softening agent for Ca2+ and Mg2+ removal with a reduced amount of generated sludge. This softening treatment simultaneously removed the suspended solids and bacteria from actual seawater. The settling velocity of the suspended solids generated via seawater softening was extremely low. Under the optimum conditions for desalinating actual seawater using an anionic polymer flocculant and microsand, the settling velocity exceeded 3.5 cm/s, 833 times higher than that of softening without ballasted flocculation. The amount of sludge after standing for 3 min was 76.5% lower in SBF than in conventional softening. The silt density index of the treated seawater met the water-supply standard of RO membranes (i.e., <3.0). Furthermore, the SBF-generated sludge exhibited considerably improved dewatering property than the sludge obtained via conventional softening. SBF can efficiently and quickly remove the causative substances of RO membrane fouling from seawater, thereby improving the treatability of generated sludge. SBF provides a new pretreatment process for seawater desalination using RO membranes.

Transcriptomics analysis reveals molecular mechanism of softening and cell wall polysaccharides-disassembling in peaches treated by flow microcirculation of sodium nitroprusside medium

Peach (Prunus persica L. Batsch. var. compressa Bean) is prone to softening during storage, and this leads to a marked deterioration in quality and shortened shelf life. The influences of sodium nitroprusside (SNP) atomization on softening development, cell wall ultrastructure, cell wall polysaccharides metabolism in peach fruit stored at 0 ± 0.5 °C for 60 d were explicated. SNP atomization treated fruit, when contrasted to the control, exhibited higher firmness, contents of chelate-soluble pectin (CSP), sodium carbonate-soluble pectin (SSP), cell wall materials (CWM), cellulose and hemicellulose (HC), but lower water-soluble pectin (WSP) content. SNP treatment suppressed activities of cell wall-degrading relevant enzymes, the disassembly of cell wall structure, and the decomposition of middle lamella and plasma membrane in peach fruit. The RNA sequencing results suggested that the differentially expressed genes from amino sugar metabolic process (beta-D-xylosidase, BXL), galactose metabolism (beta-galactosidase, β-Gal), pentose and glucuronate interconversions (polygalacturonase, PG), cellular carbohydrate metabolic process (xyloglucan- endotransglucosylase/hydrolase, XTH), and expansin (Exp) were associated with cell wall degradation in peaches with aerosolized water (control) or SNP treatments. Based on these results, the delayed softening of peaches with SNP atomization was ascribed to cell wall polysaccharides degradation regulated by gene expression levels and enzymes.

Development of Softening and Ballast Flocculation as a Pretreatment Process for Seawater Desalination Through a Reverse Osmosis Membrane

Development of Softening and Ballast Flocculation as a Pretreatment Process for Seawater Desalination Through a Reverse Osmosis Membrane

The role of cell wall polysaccharides disassembly in Lasiodiplodia theobromae-induced disease occurrence and softening of fresh longan fruit

Cell wall polysaccharides in fruits act a pivotal role in their resistance to fungal invasion. Lasiodiplodia theobromae (Pat.) Griff. & Maubl. is a primary pathogenic fungus causing the spoilage of fresh longan fruit. In this study, the influences of L. theobromae inoculation on the disassembly of cell wall polysaccharides in pericarp of fresh longans and its association with L. theobromae-induced disease and softening development were investigated. In contrast to the control, samples with L. theobromae infection showed more severe disease development, lower firmness, lower amounts of cell wall materials, covalent-soluble pectin, ionic-soluble pectin, cellulose and hemicellulose, whereas higher value of water-soluble pectin, higher activities of cell wall polysaccharide-disassembling enzymes (cellulase, β-galactosidase, polygalacturonase and pectinesterase). These findings revealed that cell wall polysaccharides disassembly induced by enzymatic manipulation was an essential pathway for L. theobromae to infect harvested longans, and thus led to the disease occurrence and fruit softening.

Numerical Modeling of Deformation Processes in Rock Pillars

The mathematical model of rock mass in the context of its internal structure, anisotropy, loss of strength, elastic energy accumulation and release is considered. The numerical solution to the problem of quasistatic deformation in a rock mass pillar is obtained by the finite element method. The sequential development of softening and residual strength zones is considered. It is shown that if the softening modulus is strong enough then the deformation process becomes unstable.

Numerical analysis of elastic-plastic compression of pillars accounting for material hardening and softening

An elastic-plastic model of rock or soil is assumed for which the yield condition depends on hydrostatic pressure and varying material density or porosity. The problem of compression of a finite rectangular pillar between two rigid plates is treated numerically in plane strain conditions by applying the ‘initial stress’ finite element incremental technique. The development of softening and hardening zones within the pillar is studied and related to the load carrying capacity of the pillar.