uniqueness principleuniqueness theoremunisexualunit barunit characterunit coal or coal or coalunit dry weightunit formunit graphunit hydrographunit matrixunit or root testunit penstockunit stratotypeunit tractive forceunit trainunit vectorunit weightunitary matrixunivariateunivariate distributionuniversal coal cutteruniversal dominationuniversal polar stereographic or ups or upsuniversal time or ut or utuniversal transverse mercator or utm or utmunlikelihoodunlinedunlined bus galleryunloadingunmixingunobservable random variableunorientedunradiogenic leadunreliability functionunrestrainedunrestrained jointunrestrained memberunrestricted random sampleunripeunsaturatedunsaturated zone or unsaturated or unsaturatedunstableunstable gravimeter or gravimeter or gravimeterunstable soilunstable stateunstable structureunsteadyunsteady flowunsteady flow simulation
