A Numerical Study of Liquid Sloshing in a Two-dimensional Tank under External Excitations

In this research, liquid sloshing behavior in a 2-D rectangular tank was simulated using ANSYS-FLUENT software subject to single or multiple-coupled external excitations （such as sway coupled with roll, and sway and roll coupled with heave）. The volume of fluid （VOF） method was used to track the free surface of sloshing. External excitation was imposed through the motion of the tank by using the dynamic mesh technique. The study shows that if the tank is subjected to multiple coupled excitations and resonant excitation frequencies, liquid sloshing will become violent and sloshing loads, including impact on the top wall, will be intensified.

An Experimental Study of the Atmospheric Oxidation of a Biogenic Organic Compound (Methyl Jasmonate) in a Thin Water Film as in Fog or Aerosols

Experiments on the reactions of OH radicals in thin films of water were conducted in a photochemical reactor. The OH radical reactivity of a biogenic molecule (methyl jasmonate) was observed to be much larger in thin films of water than in the bulk aqueous phase. The pseudo-first order reaction rate was enhanced by an order of magnitude on a 38-micron film compared to the bulk liquid. However, the first order rate constant increased by 349%. This has implications in atmospheric systems like fog and mist which have large specific surface areas. The enhanced reactivity is attributable to both the partial solvation and faster diffusion at the air-water interface compared to the bulk liquid.

A modular microfluidic platform to study how fluid shear stress alters estrogen receptor phenotype in ER+breast cancer cells

Metastatic breast cancer leads to poor prognoses and worse outcomes in patients due to its invasive behavior and poor response to therapy.It is still unclear what biophysical and biochemical factors drive this more aggressive phenotype in metastatic cancer;however recent studies have suggested that exposure to fluid shear stress in the vasculature could cause this.In this study a modular microfluidic platform capable of mimicking the magnitude of fluid shear stress(FSS)found in human vasculature was designed and fabricated.This device provides a platform to evaluate the effects of FSS on MCF-7 cell line,an estrogen receptor positive(ER+)breast cancer cell line,during circulation in the vessels.Elucidation of the effects of FSS on MCF-7 cells was carried out utilizing two approaches:single cell analysis and bulk analysis.For single cell analysis,cells were trapped in a microarray after exiting the serpentine channel and followed by immunostaining on the device(on-chip).Bulk analysis was performed after cells were collected in a microtube at the outlet of the microfluidic serpentine channel for western blotting(off-chip).It was found that cells exposed to an FSS magnitude of 10 dyn/cm^(2) with a residence time of 60 s enhanced expression of the proliferation marker Ki67 in the MCF-7 cell line at a single cell level.To understand possible mechanisms for enhanced Ki67 expression,on-chip and off-chip analyses were performed for pro-growth and survival pathways ERK,AKT,and JAK/STAT.Results demonstrated that after shearing the cells phosphorylation of p-AKT,p-mTOR,and p-STAT3 were observed.However,there was no change in p-ERK1/2.AKT is a mediator of ER rapid signaling,analysis of phosphorylated ERαwas carried out and no significant differences between sheared and non-sheared populations were observed.Taken together these results demonstrate that FSS can increase phosphorylation of proteins associated with a more aggressive phenotype in circulating cancer cells.These findings provide additional information that may help inform why cancer cells located at metastatic sites are usually more aggressive than primary breast cancer cells.

New Applications of Zirconium Phosphate Nanomaterials

CONSPECTUS:The 2-D layers of the inorganic ion exchangerα-zirconium phosphate(Zr(HPO_(4))2·H_(2)O,α-ZrP)make this compound particularly stable to low pH,high temperature,and ionizing radiation.Initially studied for its ion exchange properties,once the conditions for its synthesis in crystalline form was accomplished by James Stynes and Abraham Clearfield in 1964,numerous other types of studies and applications followed.Extensive studies in the 1960s and 1970s on the thermodynamics of ion exchange led to insights into the intercalation mechanism of this material.The Clearfield group solved the crystal structure in 1968 and refined it in 1977.Powder methods were pioneered by the Clearfield group to solve the structure of this type of materials.In 1968 Giulio Alberti reported means to prepare zirconium phosphonates expanding the chemistry of these layered compounds.New phases of ZrP were also discovered(e.g.,γ,θ,λ,τ)and the applications ranged from heterogeneous catalysis to intercalation chemistry and solid-state proton conductors.Methods to exfoliate the layers of ZrP were developed in the 1990s as interest grew in new applications of these types of materials.For example,protein and enzyme intercalation was accomplished starting in the 1990s by the McLendon,Mallouk,and Kumar groups.In the early 2000s,the Colon group pioneered the use of théθphase of ZrP for the direct intercalation of large inorganic metal complexes that could not be directly intercalated into theαphase.Initial studies in the Colon group ranged from applications of these directly intercalated ZrP derivatives in photophysics and photochemistry,́amperometric biosensors,vapochromism,and vapoluminescence.Over the past decade,new applications of these materials have been developed in anticancer drug delivery and electrocatalysis of the oxygen evolution reaction(OER).ZrP has now proven to be a promising drug nanocarrier and its unique chemical microenvironment provided by theα-type layers and the interlayer space enhances catalytic activity for numerous types of reactions.Further elucidation of the catalytic active species under operando conditions as well as the chemical structure of drug-intercalated derivatives should provide new insights that will advance the design and development of new compounds with desired properties.The initial pioneering efforts of Clearfield and Alberti are being continued by numerous research groups providing new exciting areas of development on the chemistry of layered M(IV)phosphate and phosphonate compounds.In this Account we present the efforts of the Colon group during the past decade on studies of théapplications of ZrP for anticancer drug delivery and electrocatalysis of the OER.

Effect of calcination temperature on steam reforming activity of Ni-based pyrochlore catalysts

This work served as the second part of a study evaluating the effect of calcination temperature(700-1000℃) on Ni-based lanthanum zirconate pyrochlore catalysts for methane steam reforming.A previous study(Haynes et al.Ceram.Int.2017(43) 16744) provided a thorough characterization of the material properties for the catalysts used here,and this study focuses on the evaluation of catalytic activity.The activity was assessed by two different experimental studies:the effect of reaction temperature using a temperature programmed surface reaction(TPSR),and the effect of reaction pressure.The results demonstrate a complex interaction between the Ni particles and surface LaOx species under the methane steam reforming conditions.Specifically,the material calcined at the lowest temperature(700℃) possesses the highest activity and selectivity,which is attributed to smaller and more welldispersed Ni particles on the surface,and,more importantly,a lesser degree La enrichment at the surface.All catalysts were deactivated by steam to NiO under all conditions tested,but at certain low reaction pressure(p=0.23 MPa) conditions the materials calcined at 700-900℃ are able to completely recover equilibrium activity in-situ that is then robust and stable under both low and high reaction pressures(p=1.8 MPa) suggesting the formation of a synergistic relationship between Ni and La for syngas production.However,exposure of a fresh material to high reaction pressures leads to a rapid and irreversible loss in both CH4 conversion and syngas selectivity whether in the fresh(no pretreatment),or pretreated(steam,H2 or Ar only at 800℃) form for any catalyst.The mechanism for deactivation appears to be due to the presence of LaOx species that become mobile,possibly by the formation of La-OH,and covers the active Ni particles and inhibits sites responsible for the CH4 decomposition.