Browsing by Author "Zhu, Liang"
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Item Development of an Empirical Correlation to Predict Cooling Penetration into Tissue for Practical UseCaporale, Alexander; Lombardo, Jacob; Singh, Manpreet; Zhu, LiangItem Effect of Surface Topography on Particle Deposition from Liquid Suspensions in Channel Flow(MDPI, 2020-01-05) Zaw, Myo Min; Zhu, Liang; Ma, RonghuiA Eulerian—Lagrangian model has been developed to simulate particle attachment to surfaces with arc-shaped ribs in a two-dimensional channel flow at low Reynolds numbers. Numerical simulation has been performed to improve the quantitative understanding of how rib geometries enhance shear rates and particle-surface interact for various particle sizes and flow velocities. The enhanced shear rate is attributed to the wavy flows that develop over the ribbed surface and the weak vortices that form between adjacent ribs. Varying pitch-to-height ratio can alter the amplitude of the wavy flow and the angle of attack of the fluid on the ribs. In the presence of these two competing factors, the rib geometry with a pitch-to-height ratio of two demonstrates the greatest shear rate and the lowest fraction of particle attachment. However, the ribbed surfaces have negligible effects on small particles at low velocities. A force analysis identifies a threshold shear rate to reduce particle attachment. The simulated particle distributions over the ribbed surfaces are highly non-uniform for larger particles at higher velocities. The understanding of the effect of surface topography on particle attachment will benefit the design of surface textures for mitigating particulate fouling in a wide range of applications.Item ENHANCED NANOPARTICLE DEPOSITION IN PC3 TUMORS BY MILD WHOLE BODY HYPERTHERMIA – A THEORETICAL SIMULATION(2020) Singh, Manpreet; Ma, Ronghui; Zhu, LiangItem Establishing the Need to Broaden Bioengineering Research Exposure and Research Participation in Mechanical Engineering and Its Positive Impacts on Student Recruitment, Diversification, Retention and Graduation: Findings From the UMBC ME S-STEM Scholarship Program(ASME, 2020-09-11) Zhu, Liang; Eggleton, Charles; Ma, Ronghui; Topoleski, L. D. Timmie; Madan, DeepaThe objectives of this study were to evaluate the current status of exposure to bioengineering research in community college (CC) students and University of Maryland Baltimore County (UMBC) students, and to estimate relationships between research activities sponsored by the Mechanical Engineering (ME) S-STEM Scholarship Program and improvement in student enrollment/diversification, retention rates, and graduation rates. The analysis drew on data from ME undergraduate academic records at UMBC from 2008 to 2019. A survey was designed to assess the research exposure of CC and UMBC students and their evaluation of the research components included in recruitment and curriculum activities. Results show that exposure to research measured by attending a research seminar was low for the participants, around 37% for CC students and 21% for ME students at UMBC. The survey results indicate the positive impact of the scholarship programs at UMBC on the research exposure and research experience. The impact is more evident in students who originally transferred from a CC. The large increase in recruited female and CC students over the past 10 years indicated that the researchrelated activities of the ME S-STEM program played an instrumental role in those increases. Because of the research-related activities, the ME S-STEM program achieved retention and graduation rates higher than those in the ME undergraduate program (89% versus 60% for the 6 year graduation rate), as well a higher percentage of students enrolled in graduate school (30% versus 10%). We conclude that there is still a need to implement research-related activities in the ME undergraduate program, starting with student recruitment and continuing through the academic program. Results suggest that there is a positive impact of ME S-STEM research activities on student diversification, retention rates, and percentage of our graduates who are pursuing graduate degreeItem Evaluation of STEM Engagement Activities on the Attitudes and Perceptions of Mechanical Engineering S-STEM Scholars(ASME, 2021-09-01) Zhu, Liang; Sun, Shuyan; Topoleski, L. D. Timmie; Eggleton, Charles; Ma, Ronghui; Madan, DeepaSince 2009, the mechanical engineering (ME) scholarship-science technology engineering and mathematics (S-STEM) Program at the University of Maryland Baltimore County (UMBC) has provided financial support and program activities to ME undergraduate students aiming at improving their retention and graduation rates. The objective of this study is to identify program activities that were most effective to help students for improvements. Current ME S-STEM scholars were asked to complete a survey that measures their scientific efficacy, engineering identity, expectations, integration, and sense of belonging, as well as how program activities impact their attitudes and perceptions. Analyses of 36 collected surveys showed that scholars reported high levels of engineering identity, expectations, and sense of belonging. However, further improvements were needed to help students in achieving scientific efficacy and academic integration into the program. Results demonstrated that pro-active mentoring was the most effective method contributing to positive attitudes and perceptions. The implemented S-STEM researchrelated activities and internship were viewed favorably by the scholars in helping them establish their scientific efficacy and engineering identity, and understand their expectations and goals. Community building activities were considered helpful for them to integrate into campus life and improve their sense of belonging to the campus and program. Scholars identified mentoring, research related activities, internships, and social interaction with faculty and their peers as important factors for their retention and graduation. Although the sample size was small in the study, we believe that the cost-effective activities identified could be adopted by other institutions to further improve students’ retention and graduation rates in engineering programs.Item EXTRACTION OF BASELINE BLOOD PERFUSION RATES IN MOUSE BODY AND IMPLANTED PC3 TUMOR USING INFRARED IMAGES AND THEORETICAL SIMULATION(2020) Singh, Manpreet; Flores, Hector; Ma, Ronghui; Zhu, LiangItem HEATING PROTOCOL DESIGN AFFECTED BY THERMAL DAMAGE MODEL IN MAGNETIC NANOPARTICLE HYPERTHERMIA FOR CANCER TREATMENT(2019) Singh, Manpreet; Gu, Qimei; Ma, Ronghui; Zhu, LiangItem Identifying NSF S-STEM Sponsored Program Activities that Have a Positive Impact on Mechanical Engineering S-STEM Scholars(ASEE, 2020-06-22) Zhu, Liang; Gurganus, Jamie R; Eggleton, Charles; Ma, Ronghui; Topoleski, Timmie; Madan, DeepaDue to current needs for a diverse and skilled workforce in engineering, the NSF-sponsored Mechanical Engineering (ME) S-STEM Scholarship Program in our institution (2009-present) has provided enhanced educational opportunities to more than 100 economically disadvantaged and academically talented undergraduate students in the ME Department since 2009. The NSF funded S-STEM project focuses resources on financial support, coupled with curricular and co-curricular activities designed to facilitate student degree attainment, career development, employability in STEM-related jobs, and enrollment in graduate school. In addition, our S-STEM program proactively implements engineering research-related activities, including research presentations for recruitment, in-depth lab tours, seminars, REUs, research conference support, featuring research/internship on our website, etc. In this study, we present preliminary data that reveal the attitudes and perceptions of the current 25 ME S-STEM scholars based on surveys conducted this year. The scholars were asked to provide their opinion on the impact that the activities sponsored by our S-STEM program had on their attitudes and perceptions. Results have demonstrated that faculty and peer mentoring are the most effective methods contributing to positive attitudes and perceptions. In addition, research-related activities such as lab visits, REUs, research seminars, attending research conferences, and internship opportunities are viewed favorably by the scholars as helping them establish their science/engineering self-efficacy and engineering identity, and understand their expectations and goals. On the other hand, in addition to mentoring, community building activities such as program retreats, social events, and being part of a professional society are considered as contributing to help them integrate into the campus life and improve their sense of belonging to the campus and program. In June 2019, all but two scholars were retained in our scholarship program; those who remained in the program consider all S-STEM activities favorable to their retention. Among the 10 scholars who graduated from the ME undergraduate program in the past year, 40% of them stated that they will pursue graduate degree, 20% will work in industry, and the other 40% will work in industry and enroll in a graduate school as a part-time student. Those 10 scholars identified faculty and peer mentoring, all the research-related activities sponsored by our program, internship, and social interaction with faculty and their peers as positive factors that helped them make their decisions.Item In vitro Study of Transvascular Transport of Nanostructures using a 3D Printed Microfluidic Platform(2018-08) Zaw, Myo Min; Bendler, Jordan; Ray, Arun; Lowrance, Chanda; Gu, Qimei; Daniel, Marie-Christine; Zhu, Liang; Ma, RonghuiMicrofluidics platform simulating gold nanostructures transport in tumor vascular was fabricated using 3D printing technology. Synthesis Au nanoparticles and nanorods are used to test the fabricated device using 1µm porous membrane under 20 mmHg and 5 mmHg capillary channel pressure condition. Higher capillary channel pressure has results in higher permeate of particles and rods across membrane. Compare to spherical shape nanoparticles, nanorods structure has higher permeation. Aggregation and blockage occurred around the membrane for nanorods experiment.Item MANAGING COOLING PENETRATION AND MINIMIZING SYSTEMIC HYPOTHERMIA AFTER SURGERY USING A COOLING PAD – WHOLE BODY HEAT TRANSFER SIMULATION(2020) Singh, Manpreet; Turnbaugh, Brandon; Ma, Ronghui; Zhu, LiangItem Mild Whole Body Hyperthermia Induced Interstitial Fluid Pressure (IFP) Reduction and Enhanced Nanoparticle Delivery to PC3 Tumors: In Vivo Studies and MicroCT Analyses(The American Society of Mechanical Engineers, 2020-02-28) Gu, Qimei; Liu, Shuaishuai; Ray, Arunendra Saha; Florinas, Stelios; Christie, Ronald James; Daniel, Marie-Christine; Bieberich, Charles; Ma, Ronghui; Zhu, LiangIn vivo experiments on mice were performed to evaluate whether whole body hyperthermia enhances nanoparticle delivery to PC3 tumors. The mice in the experimental group were subjected to whole body hyperthermia by maintaining their body temperatures at 40ºC for one hour. Interstitial fluid pressures (IFPs) in tumors were measured before heating, immediately after, and at 2 and 24 hours post-heating in both the experimental group and in a sham group (without heating). 0.2 cc of a newly developed nanofluid containing gold nanoparticles (AuNPs) was delivered via the tail vein in both groups. MicroCT scanned images of resected tumors were analyzed to visualize nanoparticle distribution in the tumors and to quantify the total amount of the nanoparticles delivered to the tumors. Statistically significant IFP reductions of 45% right after heating, 47% 2 hours post heating, and 52% 24 hours post heating were observed in the experimental group. Analyses of microCT scans of the resected tumors illustrated that nanoparticles were more concentrated near the tumor periphery rather than at the tumor center. The 1-hour whole body hyperthermia treatment resulted in more nanoparticles present in the tumor central region than that in the control group. The mass index calculated from the microCT scans suggested overall 42% more nanoparticle delivery in the experimental group than that in the control group. We conclude that 1-hour mild whole body hyperthermia leads to sustained reduction in tumoral IFPs and significantly increases the total amount of targeted gold nanoparticle deposition in PC3 tumors.Item Modeling molten droplet spreading and infiltration into non-isothermal thermal barrier coatings(Elsevier, 2021-09-27) Munuhe, Timothy W.; Chen, Ruey-Hung; Zhu, Liang; Ma, RonghuiMolten calcium-magnesium-alumino-silicate (CMAS) droplets impact and infiltrate porous thermal barrier coatings (TBCs) of gas turbines, thereby causing loss of strain tolerance and delamination of the ceramic topcoat. To develop efficient mitigation strategies, it is crucial to understand CMAS infiltration dynamics into the porous topcoat. An integrated model is introduced incorporating simultaneous droplet spreading, wetting interactions, heat transfer, and liquid infiltration with temperature-dependent viscosities in unsaturated porous media. The model is applied to CMAS droplet interactions with homogeneous/heterogeneous anisotropic TBC topcoats grown by the electron beam physical vapor deposition (EB-PVD) method. Simulation results show that the droplet height and contact diameter dynamics exhibit three stages - initial-stage fast decrease, slow quasi-linear intermediate decrease, and late-stage fast decrease. The first two stages are dominated by the dynamics of infiltration. The initial temperature of the droplet has insignificant effect on the infiltration dynamics. Rather, the temperature gradient in the topcoat is critical to the infiltration rate. The anisotropy determines the final infiltration diameter and depth. Further, bilayer and multilayer coating structures with alternating fine and coarse columns can delay the infiltration rate and promote lateral spreading during the early stage of the droplet infiltration compared to single-layer structures. The results demonstrate that heterogeneous structures provide a viable approach to mitigate fast infiltration and reduce damage to the TBCs during the early stage of droplet infiltration.Item Nanoparticle Delivery in Prostate Tumors Implanted in Mice Facilitated by Either Local or Whole-Body Heating(MDPI, 2021-07-31) Gu, Qimei; Dockery, Lance; Daniel, Marie-Christine; Bieberich, Charles; Ma, Ronghui; Zhu, LiangThis work discusses in vivo experiments that were performed to evaluate whether local or whole-body heating to 40 °C reduced interstitial fluid pressures (IFPs) and enhanced nanoparticle delivery to subcutaneous PC3 human prostate cancer xenograft tumors in mice. After heating, 0.2 mL of a previously developed nanofluid containing gold nanoparticles (10 mg Au/mL) was injected via the tail vein. The induced whole-body hyperthermia led to increases in tumor and mouse body blood perfusion rates of more than 50% and 25%, respectively, while the increases were much smaller in the local heating group. In the whole-body hyperthermia groups, the IFP reduction from the baseline at the tumor center immediately after heating was found to be statistically significant when compared to the control group. The 1 h of local heating group showed IFP reductions at the tumor center, while the IFPs increased in the periphery of the tumor. The intratumoral gold nanoparticle accumulation was quantified using inductively coupled plasma mass spectrometry (ICP-MS). Compared to the control group, 1 h or 4 h of experiencing whole-body hyperthermia resulted in an average increase of 51% or 67% in the gold deposition in tumors, respectively. In the 1 h of local heating group, the increase in the gold deposition was 34%. Our results suggest that 1 h of mild whole-body hyperthermia may be a cost-effective and readily implementable strategy for facilitating nanoparticle delivery to PC3 tumors in mice.Item A New Simplified Bioheat Equation for the Effect of Blood Flow on Local Average Tissue Temperature(The American Society of Mechanical Engineers, 2019-02-11) Zhu, Liang; Bischof, JohnThe Journal of Biomechanical Engineering has contributed to biomechanical engineering field since 1977. To honor papers published at least 30 years that have had a long-lasting impact on the field, the Editors now recognize "Legacy Papers." The journal is pleased to present the following paper as this year's Legacy Paper: "A New Simplified Bioheat Equation for the Effect of Blood Flow on Local Average Tissue Temperature" by S. Weinbaum and L. Jiji, ASME Journal of Biomechanical Engineering 107: 131-139, 1985.Item Outcomes of the S-STEM Scholarship Program in Our Institution in the Past Three Years(American Society for Engineering Education, 2021-07-26) Zhu, Liang; Eggleton, Charles; Topoleski, L.D. Timmie; Ma, Ronghui; Madan, DeepaOur institution was awarded an S-STEM grant in 2018 to continue to provide scholarships and educational opportunities to low-income and talented undergraduate mechanical engineering students. Since then, 44 undergraduate students with diverse backgrounds in Mechanical Engineering department have been awarded the scholarships. In addition to financial support, the S-STEM scholars are connected to individual faculty mentors and provided with opportunities of internships, research-related experiences, and community building activities. The large and diverse applicant pool allowed us to award 22-27 scholarships to students each year, exceeding the targeted annual number of 20 scholarships. Academic records demonstrate that all the proposed benchmarks have been exceeded, especially in the retention rate (91%), diversity of student population, research experience/internship participation (55%), and percentage of our scholars enrolled in graduate school after their graduation (29%). All are higher than that in the regular student population in our department. The results suggested that faculty and peer mentoring, proactive research-related activities, engagement in internship, and interaction with faculty and their peers might contribute positively to the success of the scholars in our program. Some of the cost-effective program activities have been implemented in our undergraduate program, and could be adapted by engineering programs in other institutions. With continuous commitment by faculty members and department/college recognition, the positive impact of the program could be sustained via merging into existing undergraduate program.Item PERFORMANCE OF SKIN COOLING DEVICE IN COOLING PENETRATION IN TISSUE – EXPERIMENTS AND SIMULATIONS(2022-06) Singh, Manpreet; Lombardo, Jacob; Caporale, Alexander; Zhu, LiangItem SAFE DURATION OF A PERSON SOAKING INSIDE A HOT TUB: THEORETICAL PREDICTION OF TEMPERATURE ELEVATIONS IN HUMAN BODIES USING A WHOLE BODY HEAT TRANSFER MODELZaw, Myo Min; Singh, Manpreet; Ma, Ronghui; Zhu, LiangSoaking in hot tubs has become a popular relaxation activity during all seasons. Unfortunately, hot tub related emergency visits increase in recent years. Based on a New York Times article, approximately more than 6000 emergency visits in 2007 are related to hot tube injury. Although most of the injuries were due to slips or falls, still more than 10% of those visits were heat stroke related. People often mistakenly assume a sense of safety since the head is typically not soaking inside the hot water. Understanding how high the body temperature especially the brain temperature will rise is crucial to educate the public to prevent heat stroke from happening when using hot tubs.1 In this study, we first develop a whole body model based on measurements of a human body, with realistic boundary conditions incorporated before and after a person jumps into a hot tub. For the transient heat transfer simulation, the initial condition is the established steady state temperature field of the human body with appropriate clothing layer to ensure thermal equilibrium of the body with its surroundings. Once the person is inside a hot tub, the Pennes bioheat equation is used to simulate the transient temperature elevations of the body, and the rising of the arterial blood temperature is solved by an energy balance equation modeling thermal exchange between body tissue and the blood in the body.3 The safe duration of soaking in hot tubs is then determined as affected by the hot tub water temperatures.Item THEORETICAL EVALUATION OF TEMPERATURE ELEVATION, THERMAL DAMAGE, TRANSPORT POROSITY ENHANCEMENT, AND MAGNETIC NANOPARTICLE MIGRATION IN TUMORS DURING LOCAL HEATING(2019) Singh, Manpreet; Ma, Ronghui; Zhu, Liang