Analysis of the Functional Components of Acid Protease and Investigation of Bating Mechanism of Wet-blue

Content: In this study, different acid proteases, which were produced from Aspergillus and Bacillus, were applied for wet-blue bating and their properties and bating effects were observed. The results showed that the acid protease produced Aspergillus had better bating effect and higher chromium tolerance than that of produced by Bacillus. Furthermore, how the acid protease influenced wet-blue microstructure was analyzed by SEM and Micro-CT. The enzymatic properties of acid protease was studied firstly.Zeta potential analysis showed that the isoelectric point (pI) of the protease was consistent with its pH value, which was at 3.0. By particle size analysis, it found that its particle size was 700 nm. In order to obtain the functional components, the molecular weight of the acidic protease was analyzed by Polyacrylamide gel Electrophoresis (SDS-PAGE). Different molecular weight components were obtained by separating the acidic protease with Tangential Flow Filtration (TFF) Technology. The characteristics of these components were determined such as enzyme types and their proportion. Afterwards, these different molecular weight components were used for wet-blue bating. The bating effluent was collected, and then, contents of Hydroxyproline (Hyp), Hyaluronic acid (HA), Desmosine (Des) and Chondroitin sulfate (CS) were analysed, which could be directly corresponding with the degradation of different proteins in wet-blue. Therefore, by characterizing and comparing the bating effect influenced with these different molecular weight components, the functional components of protease could be identified and further be separated and purified. Based on these results, this research is helpful to the development and study of the action of acid protease in the wet-blue bating process. Take-Away: Micro-CT as a new way to characterize the microstructure of leather; Identification and Separation of Effective Components of Acid Protease； Degradation Analysis of Main Components of Wet-Blue during bating process

Experimental study on the effect of confining pressure and interval time on the fatigue mechanical properties of mudstone

The mudstone interlayer experiences discontinuous cyclic loading during gas storage reservoir operation. To investigate the effects of intermittent action and confining pressure on the fatigue mechanical properties of mudstone. Continuous fatigue test and graded intermittent fatigue test were conducted respectively. The results show that: 1. the fatigue life of mudstone is enhanced by the intermittent effect during the fatigue process. The presence of confining pressure under the same experimental conditions also benefits the fatigue life of mudstone.2. the average modulus of elasticity of mudstone decreases with increasing stress level during cyclic loading, and both intermittency and confining pressure help to enhance the modulus of elasticity of mudstone.3. in graded intermittent fatigue tests. In both uniaxial and triaxial tests, the residual strains generated by the post-interval cycles are smaller than those generated before the intervals.4. In the 3MPa graded interval fatigue test, negative deformation occurs in the post-interval cycle due to the release of elastic energy

Bauxite Mining Conflicts in Guinea: Causes Identification, Analysis, and Countermeasures

International audienceMining conflicts are among the most widespread issues linked to natural resources development and management in mineral-rich countries. Guinea mining industries development presents a huge challenge in promoting integrated, prosperous, peaceful, and sustainable mining. The scramble of companies to exploit bauxite in the Boké region is correlated with a wave of protests and violent conflicts. This article explores the reasons for the resurgence of conflicts in the Guinea Republic, proposes some strategies for better mining conflicts prevention, management in Boke region. Thus, through a survey carried out in 7 Municipalities of the region and other mining localities of the country, we use a quantitative approach through descriptive statistic elements to identify the causes of the outburst of the conflict in Boke which seriously hinders the climate of socioeconomic activities for local development. The outcomes of this study reveal that youth employment, water and electricity supply, the weakness in the management of compensation mechanism are the main reasons for conflict escalation in Boke. Although, solutions proposed by the state and some NGOs appear to be hopeful. However, better management of public services and good governance based on more innovative public-private partnerships, and changes in government policy to better benefit the local communities could solve these problems holistically. The implementation of a better strategy (approach) in the management of relations with the surrounding communities by considering the depths and the sociohistorical, cultural, economic characteristics of the region would guarantee an environment of peaceful cohabitation between the local communities and the companies

Fatigue effects of discontinuous cyclic loading on the mechanical characteristics of sandstone

International audienc

Influence of storage layout on stability of horizontal storage group in bedded salt rocks

With the rapid development of China's economy and society in recent years, the demand for oil and natural gas is growing day by day, and a large number of underground energy reserves have begun to be built in salt rocks. Under the engineering background of a proposed underground oil storage group in bedded salt rocks in a salt mine in Jiangsu Province, a numerical simulation model of horizontal oil storage group was established with the finite element analysis method, using FLAC3D software as the platform. Meanwhile, the stability of storage group with different pillar widths in rectangular and diamond-shaped well layout was simulated and analyzed. In addition, the variation laws of the displacement distribution of surrounding rock, the volume shrinkage, the volume of plastic zone and the maximum vertical displacements of roof and floor after 30 years of operation of the storage groups were analyzed. The result shows that it is a reasonable layout to ensure the stability of the horizontal oil storage groups by adopting diamond-shaped well layout and setting the pillar widths not less than 1.75 times of the storage diameter. In addition, the results were verified according to the stability criterion, which shows that the stability conditions are satisfied. Generally, the research results could provide reference to the construction of underground oil storage groups in bedded salt rocks in China in the future