Mechanical Engineering (MNE) Seminar by Kevin Raggiani and Md Elius
When: Friday,
April 15, 2022
2:00 PM
-
3:00 PM
Description: Mechanical Engineering (MNE) SEMINAR
DATE:
Friday, April 15, 2022
TIME:
2:00 p.m. - 3:00 p.m.
LOCATION:
Charlton College of Business (CCB), Room 115
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SPEAKER #1:
Kevin Raggiani, MS student in Mechanical Engineering (Advisor: Mehdi Raessi)
TOPIC:
Computational Investigation of Water Entry of Solid Objects with Various Nose Curvatures
ABSTRACT:
Water entry of solid objects is relevant in many applications. Following the impact of a solid on the water free-surface, an air-entraining cavity forms. Previous studies have identified four general types of cavities: deep, surface, shallow and quasi-static. Although with advancements in experimental methods, image capturing techniques, and high performance computing the underlying physics are becoming better understood, the challenge of predicting the resulting cavity shape still remains. The dynamics strongly depend on fluid and solid properties, as well as impact parameters. To improve our understanding on cavity formation and its shape, we present 3D multiphase flow simulations investigating the effect of nose shape and Weber number on cavity formation. In our study, a stainless steel cylinder is used where the curvature of the leading edge (nose) is varied from concave to convex, resulting in various cavity seals and splashing crowns upon water entry.
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SPEAKER #2:
Md Elius, MS student in Mechanical Engineering (Advisor: Hangjian Ling)
TOPIC:
Study of Bacterial Motion and Biofilm Formation by Digital Holographic Microscopy
ABSTRACT:
Marine biofouling, defined as the accumulation of marine organisms on ocean-submerged surfaces, produces adverse impacts on the unprotected vessels, naval fleets, offshore infrastructures, and undersea sensors. Biofilm, a thin layer of bacteria growing on a solid surface, is usually the first stage of the biofouling formation. Therefore, understanding the adhesion mechanism of marine bacteria on solid walls is crucial for the development of the next-generation of anti-biofouling technologies. In this study, we apply the Digital Holographic Microscopy (DHM), a high-resolution, three-dimensional (3D) imaging technology, to study the 3D motion of bacteria near the solid surfaces. We have successfully tracked the 3D motions of 100 to 500 Shewanella (a type of marine bacteria) in a 10 mm by 45 mm by 0.2 mm glass chamber. We found distinct behavior of bacteria in the bulk liquids and near wall region. In the bulk region, run and random motions are more common. While near the wall, spinning and tumbling motions are more often seen. In this talk, we will describe the principle of DHM, the experimental setup, data analysis procedures, and preliminary results. Furthermore, I will describe the fabrication method of superhydrophobic surfaces, a novel material showing very promising anti-biofouling properties. In future, our goal is to investigate the bacterial motion on superhydrophobic surfaces.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE BS and MS students are encouraged to attend. EAS students are also encouraged to attend.
DATE:
Friday, April 15, 2022
TIME:
2:00 p.m. - 3:00 p.m.
LOCATION:
Charlton College of Business (CCB), Room 115
------------------------------------------------------------
SPEAKER #1:
Kevin Raggiani, MS student in Mechanical Engineering (Advisor: Mehdi Raessi)
TOPIC:
Computational Investigation of Water Entry of Solid Objects with Various Nose Curvatures
ABSTRACT:
Water entry of solid objects is relevant in many applications. Following the impact of a solid on the water free-surface, an air-entraining cavity forms. Previous studies have identified four general types of cavities: deep, surface, shallow and quasi-static. Although with advancements in experimental methods, image capturing techniques, and high performance computing the underlying physics are becoming better understood, the challenge of predicting the resulting cavity shape still remains. The dynamics strongly depend on fluid and solid properties, as well as impact parameters. To improve our understanding on cavity formation and its shape, we present 3D multiphase flow simulations investigating the effect of nose shape and Weber number on cavity formation. In our study, a stainless steel cylinder is used where the curvature of the leading edge (nose) is varied from concave to convex, resulting in various cavity seals and splashing crowns upon water entry.
------------------------------------------------------------
SPEAKER #2:
Md Elius, MS student in Mechanical Engineering (Advisor: Hangjian Ling)
TOPIC:
Study of Bacterial Motion and Biofilm Formation by Digital Holographic Microscopy
ABSTRACT:
Marine biofouling, defined as the accumulation of marine organisms on ocean-submerged surfaces, produces adverse impacts on the unprotected vessels, naval fleets, offshore infrastructures, and undersea sensors. Biofilm, a thin layer of bacteria growing on a solid surface, is usually the first stage of the biofouling formation. Therefore, understanding the adhesion mechanism of marine bacteria on solid walls is crucial for the development of the next-generation of anti-biofouling technologies. In this study, we apply the Digital Holographic Microscopy (DHM), a high-resolution, three-dimensional (3D) imaging technology, to study the 3D motion of bacteria near the solid surfaces. We have successfully tracked the 3D motions of 100 to 500 Shewanella (a type of marine bacteria) in a 10 mm by 45 mm by 0.2 mm glass chamber. We found distinct behavior of bacteria in the bulk liquids and near wall region. In the bulk region, run and random motions are more common. While near the wall, spinning and tumbling motions are more often seen. In this talk, we will describe the principle of DHM, the experimental setup, data analysis procedures, and preliminary results. Furthermore, I will describe the fabrication method of superhydrophobic surfaces, a novel material showing very promising anti-biofouling properties. In future, our goal is to investigate the bacterial motion on superhydrophobic surfaces.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE BS and MS students are encouraged to attend. EAS students are also encouraged to attend.
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