?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F282%2F&rft.title=The+dynamics+of+liquid+slugs+forced+by+a+syringe+pump&rft.creator=Miraghaie%2C+Reza&rft.creator=Abouali%2C+M.&rft.creator=Breward%2C+C.&rft.creator=Chan%2C+I.&rft.creator=Ellis%2C+A.&rft.creator=Fehribach%2C+J.&rft.creator=Gratton%2C+M.+B.&rft.creator=Matusik%2C+K.&rft.subject=Medical+and+pharmaceutical&rft.description=Microfluidic+processes+for+chemical+synthesis+have+become+popular+in+recent+years.+The+small+scale+of+the+chemical+reactions+promise+greater+control+over+reaction+conditions+and+more+timely+creation+of+products.+The+small+scale+of+microfluidics+poses+its+own+set+of+problems%2C+however.+At+the+microscale%2C+the+dominant+fluid+forces+are+viscous+resistance+and+surface+tension.+The+effects+of+viscosity+and+scale+reduce+the+Reynolds+number+and+make+mixing+difficult.+Much+work+has+been+done+to+control+mixing+at+the+microscale.%0D%0A%0D%0AThis+problem+is+concerned+with+a+different+microfluidic+problem%3A+delivering+reactants+to+the+site+of+reaction.+A+common+setup+is+to+attach+syringes+full+of+reactant+to+a+reaction+chamber+by+narrow+hydrophobic+tubing.+Using+a+stepper+motor%2C+a+controlled+dose+of+liquid+may+be+injected+into+the+tube.+The+hydrophobosity+causes+the+dose+to+curve+outward+on+the+sides%2C+becoming+a+%22slug%22+of+reactant+with+air+in+front+and+behind.+The+syringe+at+the+rear+is+then+switched+for+one+full+of+air%2C+and+air+pressure+is+used+to+drive+the+slug+to+the+reaction+site.%0D%0A%0D%0AIf+too+much+pressure+is+applied%2C+the+slug+will+arrive+with+a+significant+back+pressure+that+will+be+relieved+through+bubbling+in+the+reaction+site.+This+causes+the+formation+of+a+foam+and+is+highly+undesirable.+We+present+a+simple+model+based+on+Boyle%E2%80%99s+law+for+the+motion+of+a+slug+through+a+tube.+We+then+extend+this+model+for+trains+of+slugs+separated+by+air+bubbles.+Last%2C+we+consider+the+case+of+a+flooded+reaction+site%2C+where+the+forward+air+bubble+must+be+pushed+through+the+flooding+liquid.%0D%0A%0D%0AIn+conclusion%2C+we+have+determined+the+dynamics+of+a+single+slug+moving+towards+an+empty+reaction+chamber+giving+the+final+equilibrium+position+of+the+slug.+A+phase-plane+analysis+then+determined+a+condition+on+the+size+of+the+slug+needed+to+ensure+that+it+comes+to+rest+without+oscillating+about+the+equilibrium+position.+The+effect+of+a+flooded+reaction+chamber+was+then+considered.+In+this+case+it+is+impossible+to+avoid+bubbling+due+to+the+design+of+the+device.+We+found+that+it+is+possible%2C+however%2C+to+reduce+the+bubbling+by+minimising+the+back+pressure+behind+the+slug.+Finally%2C+the+dynamics+of+multiple+slugs+with+or+without+a+flooded+reaction+chamber+has+been+investigated.&rft.date=2009&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F282%2F1%2F1_Siemens_Healthcare.pdf&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F282%2F2%2F1_Siemens_Healthcare_-_presentation.pdf&rft.identifier=++Miraghaie%2C+Reza+and+Abouali%2C+M.+and+Breward%2C+C.+and+Chan%2C+I.+and+Ellis%2C+A.+and+Fehribach%2C+J.+and+Gratton%2C+M.+B.+and+Matusik%2C+K.++(2009)+The+dynamics+of+liquid+slugs+forced+by+a+syringe+pump.++%5BStudy+Group+Report%5D+++++