STABILITY AND POLES LOCATION ANALYSIS FOR PERTURBED DISCRETE/CONTINUOUS SYSTEMS

Research using chaos theory allows for a better understanding of many phenomena modeled by means of dynamical systems. The appearance of chaos in a given process can lead to very negative effects, e.g., in the construction of bridges or in systems based on chemical reactors. This problem is important, especially when in a given dynamic process there are so-called hidden attractors. In the scientific literature, we can find many works that deal with this issue from both the theoretical and practical points of view. The vast majority of these works concern multidimensional continuous systems. Our work shows these attractors in discrete systems. They can occur in Newton’s recursion and in numerical integration.

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Generation of Photopolymerized Microparticles Based on PEGDA Using Microfluidic Devices. Part 1. Initial Gelation Time and Mechanical Properties of the Material

Micromachines ◽

10.3390/mi12030293 ◽

2021 ◽

Vol 12 (3) ◽

pp. 293

Author(s):

José M. Acosta-Cuevas ◽

José González-García ◽

Mario García-Ramírez ◽

Víctor H. Pérez-Luna ◽

Erick Omar Cisneros-López ◽

...

Keyword(s):

Mechanical Properties ◽

Gelation Time ◽

Mesh Size ◽

Microfluidic Devices ◽

Future Generation ◽

Mechanical Tests ◽

Continuous Systems ◽

Polyethylene Glycol Diacrylate ◽

Glycol Diacrylate ◽

Close Relationship

Photopolymerized microparticles are made of biocompatible hydrogels like Polyethylene Glycol Diacrylate (PEGDA) by using microfluidic devices are a good option for encapsulation, transport and retention of biological or toxic agents. Due to the different applications of these microparticles, it is important to investigate the formulation and the mechanical properties of the material of which they are made of. Therefore, in the present study, mechanical tests were carried out to determine the swelling, drying, soluble fraction, compression, cross-linking density (Mc) and mesh size (ξ) properties of different hydrogel formulations. Tests provided sufficient data to select the best formulation for the future generation of microparticles using microfluidic devices. The initial gelation times of the hydrogels formulations were estimated for their use in the photopolymerization process inside a microfluidic device. Obtained results showed a close relationship between the amount of PEGDA used in the hydrogel and its mechanical properties as well as its initial gelation time. Consequently, it is of considerable importance to know the mechanical properties of the hydrogels made in this research for their proper manipulation and application. On the other hand, the initial gelation time is crucial in photopolymerizable hydrogels and their use in continuous systems such as microfluidic devices.

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Location analysis of fish port complex planning in Surabaya City based on Integrated Coastal Zone Management (ICZM) approach

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/562/1/012011 ◽

2020 ◽

Vol 562 ◽

pp. 012011

Author(s):

A F Multazam ◽

D Rahmawati

Keyword(s):

Coastal Zone ◽

Coastal Zone Management ◽

Location Analysis ◽

Integrated Coastal Zone Management ◽

Zone Management ◽

Complex Planning

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Investigating the performance of agricultural wastes and their ashes in removing phenol from leachate in a fixed-bed column

Water Science & Technology ◽

10.2166/wst.2020.274 ◽

2020 ◽

Vol 81 (10) ◽

pp. 2109-2126 ◽

Cited By ~ 1

Author(s):

Seyed Omid Ahmadinejad ◽

Seyed Taghi Omid Naeeni ◽

Zahra Akbari ◽

Sara Nazif

Keyword(s):

Activated Carbon ◽

Large Scale ◽

Fixed Bed ◽

Walnut Shell ◽

Continuous Systems ◽

Phenol Removal ◽

Adsorption Method ◽

Fixed Bed Column ◽

Saturation Time ◽

Coconut Shell Activated Carbon

Abstract One of the major pollutants in leachate is phenol. Due to safety and environmental problems, removal of phenol from leachate is essential. Most of the adsorption studies have been conducted in batch systems. Practically, large-scale adsorption is carried out in continuous systems. In this research, the adsorption method has been used for phenol removal from leachate by using walnut shell activated carbon (WSA) and coconut shell activated carbon (CSA) as adsorbents in a fixed-bed column. The effect of adsorbent bed depth, influent phenol concentration and type of adsorbent on adsorption was explored. By increasing the depth of the adsorbent bed in the column, phenol removal efficiency and saturation time increase significantly. Also, by increasing the influent concentration, saturation time of the column decreases. To predict the column performance and describe the breakthrough curve, three kinetic models of Yon-Nelson, Adams-Bohart and Thomas were applied. The results of the experiments indicate that there is a good match between the results of the experiment and the predicted results of the models.

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