Ph.D., Engineering Sciences (Engineering Physics)
B.Sc., Engineering Science
Nuclear News print
Ten years ago, Virginia Commonwealth University’s Department of Mechanical Engineering added nuclear engineering to its program offerings, bringing comprehensive nuclear engineering education back to Virginia. Today, VCU is the only university in Virginia with an accredited undergraduate nuclear engineering major concentration, as well as M.S. and Ph.D. programs in mechanical and nuclear engineering. Those programs are making robust intellectual contributions to the discipline while also meeting significant industry needs. The idea to create them came about when industry and academia came together to solve a problem. “Sama really is the perfect person to head our nuclear programs because of her vast industry and policy experience,” said Gary Tepper, who has been chair of the Department of Mechanical and Nuclear Engineering since 2009. He said that adding nuclear engineering to the department’s offerings has boosted enrollment. “In 2009, we had about 300 students,” Tepper said. “When we added the nuclear concentration, we went to nearly 600 students in a short time. It gave the program visibility and gave students options.”view more
Mesh-like fiber mats of polystyrene (PS) were deposited using DC-biased AC-electrospinning. Superhydrophobic surfaces with water contact angles greater than 150° and gas fraction values of up to 97% were obtained. Rheological study was conducted on these fiber surfaces and showed a decrease in shear stress when compared with a noncoated surface (no slip), making them excellent candidates for applications requiring the reduction of skin-friction drag in submerged surfaces. We have also shown that addition of a second, low-surface energy polymer to a solution of PS can be used to control the fiber internal porosity depending on the concentration of the second polymer. Contact-angle measurements on mats consisting of porous and nonporous fibers have been used to evaluate the role of the larger spaces between the fibers and the pores on individual fibers on superhydrophobicity.
A bulk heterojunction organic solar cell with co-planar interdigitated electrodes was fabricated and tested. The co-planar electrodes had a separation distance of 1–3 μm and were fabricated from aluminum and nickel on a heavily oxidized silicon wafer using photolithography. The device was prepared by spin-coating MEH-PPV:PCBB in a 1:3 wt ratio with a total donor:acceptor solution concentration of 2.44%. The device demonstrated a strong photovoltaic response under AM1.5 illumination of 80 mW/cm2 with an open circuit voltage of 0.704 V. The co-planar electrode design offers advantages in terms of electrode material selection and reliability as well as simplified device fabrication.
We show that nanoporous anodic alumina films, with pore diameters in the range 10–80 nm, can be transformed from being very hydrophilic (or super-hydrophilic) to very hydrophobic (or super-hydrophobic) by coating the surface with a thin (2–3 nm) layer of a hydrophobic polymer. This dramatic transformation happens as a result of the interplay between surface morphology and surface chemistry. The coated surfaces exhibit 'sticky' hydrophobicity as a result of ingress of water into the pores by capillary action. The wetting parameters (contact angle and contact angle hysteresis) exhibit qualitatively different dependences on pore diameters in coated and uncoated films, which are explained by invoking appropriate models for wetting.