A mathematical model of a parallel plate electrochemical cell with a separator and a homogeneous bulk reaction is presented. The model is based on the Zn]Br,~ redox couple and can be used as an aid for the design of an efficient rechargeable storage battery. It is shown that four independent variables exist for the system at a fixed temperature: the effective separator thickness, the residence time, the channel width, and the potential driving force. Performance criteria of interest for the Zn]Br.2 battery are defined. Predictions of performance during the charging process are presented. It is shown that the cell performance improves as the effective thickness of the separator is increased, despite the associated greater cell resistance. It is also shown that a change in the residence time has little effect on cell performance. Po where po is the resistivity of a solution without a separa-Downloaded 06 Jun 2011 to 129.252.106.103.

Polymethylmethacrylate (PMMA) is one of the most important thermoplastic materials and is a widely used material in microfluidics. However, PMMA is usually structured using industrial scale replication processes, such as hot embossing or injection molding, not compatible with rapid prototyping. In this work, we demonstrate that microfluidic chips made from PMMA can be 3D printed using fused deposition modeling (FDM). We demonstrate that using FDM microfluidic chips with a minimum channel cross-section of ~300 µm can be printed and a variety of different channel geometries and mixer structures are shown. The optical transparency of the chips is shown to be significantly enhanced by printing onto commercial PMMA substrates. The use of such commercial PMMA substrates also enables the integration of PMMA microstructures into the printed chips, by first generating a microstructure on the PMMA substrates, and subsequently printing the PMMA chip around the microstructure. We further demonstrate that protein patterns can be generated within previously printed microfluidic chips by employing a method of photobleaching. The FDM printing of microfluidic chips in PMMA allows the use of one of microfluidics’ most used industrial materials on the laboratory scale and thus significantly simplifies the transfer from results gained in the lab to an industrial product.

Glass is one of the most relevant high-performance materials that has the benefit of a favorable environmental footprint compared with that of other commodity materials. Despite the advantageous properties of glasses, polymers are often favored because they can be processed using scalable industrial replication techniques like injection molding (IM). Glasses are generally processed through melting, which is both energy intensive and technologically challenging. We present a process for glassworks using high-throughput IM of an amorphous silicon dioxide nanocomposite that combines established process technologies and low-energy sintering. We produce highly transparent glass using classical IM and sintering, allowing for a potentially substantial reduction in energy consumption. Our strategy merges polymer and glass processing, with substantial implications for glass utilization.

Fortunately, primary tumors of the heart and great vessels are rare. These primary tumors include angiosarcoma, malignant fibrous histiocytoma, high-grade and pleomorphic sarcoma, and paraganglioma with pericardial and myocardial invasion. Symptoms are often nonspecific and include chest pain and dyspnea. Although these tumors are often diagnosed with echocardiography and computed tomography, magnetic resonance (MR) imaging currently appears to be the imaging modality of choice because of its diverse capabilities, which include multiplanar imaging for excellent anatomic definition of the heart, pericardium, mediastinum, and lungs; improved morphologic differentiation between tumor tissue and surrounding cardiovascular, mediastinal, or pulmonary tissues; dynamic imaging with a gated cine-loop acquisition; and assessment of tissue perfusion. The use of gadopentetate dimeglumine is helpful in achieving tumor enhancement on MR images but is not required. MR imaging is also useful in assessing tumor response to surgery, radiation therapy, and chemotherapy.

A material balance closure calculation is presented to test the consistency of a previously published model of a parallel plate electrochemical reactor. New expressions are used in this procedure to calculate the average concentration of species normali and the average current density for reaction normalj from the predicted concentration and potential distributions. Also, the previously presented model equations are simplified by assuming that the axial concentration gradient for species normali can be approximated by a step change from the known feed concentration to the unknown outlet concentration. This one‐step model provides a qualitative evaluation of cell performance and adds insight into understanding of the previous model, while providing substantial savings in computer time. The models are compared using a hypothetical case of the electrowinning of copper from a chloride solution. For a small aspect ratio false(S/Lfalse) , the models show that a set of independent variables consists of the cell potential false(Enormalcellfalse) , the surface area of an electrode per unit of cell volume false(1/Sfalse) , and the residence time false(L/υnormalavgfalse) when the feed concentrations false(cnormali,normalfeedfalse) are fixed.