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  <xs:element id="shc_ScheduleOfShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsValuationAssumptionsTableTextBlock" abstract="false" name="ScheduleOfShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsValuationAssumptionsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
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  <xs:element id="shc_LitigationSettlementAmountAwardedFromOtherPartyBeforePreJudgmentInterest" abstract="false" name="LitigationSettlementAmountAwardedFromOtherPartyBeforePreJudgmentInterest" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_EffectiveIncomeTaxRateReconciliationImpactOfCARESActAndFinal951ARegulations" abstract="false" name="EffectiveIncomeTaxRateReconciliationImpactOfCARESActAndFinal951ARegulations" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesPurchaseOfInterestByParentPercentage" abstract="false" name="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesPurchaseOfInterestByParentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
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  <xs:element id="shc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentWorkingCapitalNet" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentWorkingCapitalNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="shc_LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearThree" abstract="false" name="LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionNonvestedWeightedAverageRemainingContractualTerm" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionNonvestedWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="shc_WriteOffOfDeferredDebtIssuanceCostAndDebtDiscount" abstract="false" name="WriteOffOfDeferredDebtIssuanceCostAndDebtDiscount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearFive" abstract="false" name="LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearFive" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_LicensingAgreementsRenewalTerm" abstract="false" name="LicensingAgreementsRenewalTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="shc_DefinedBenefitPlanBenefitObligationUnrecognizedActuarialGainLoss" abstract="false" name="DefinedBenefitPlanBenefitObligationUnrecognizedActuarialGainLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_AcquisitionAndDivestitureRelatedChargesNet" abstract="false" name="AcquisitionAndDivestitureRelatedChargesNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInvestmentInUnconsolidatedAffiliate" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInvestmentInUnconsolidatedAffiliate" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearTwo" abstract="false" name="LesseeOperatingandFinanceLeaseLiabilityPaymentsDueYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_PercentOfPropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" abstract="false" name="PercentOfPropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="shc_DepreciationExpenseAssetRetirementObligation" abstract="false" name="DepreciationExpenseAssetRetirementObligation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="shc_FinanceLeaseCost" abstract="false" name="FinanceLeaseCost" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_SecondaryOfferingMember" abstract="true" name="SecondaryOfferingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_GoodwillAndOtherIndefiniteLivedIntangiblesPolicyPolicyTextBlock" abstract="false" name="GoodwillAndOtherIndefiniteLivedIntangiblesPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="shc_PercentOfRevenueFromContractWithCustomerExcludingAssessedTax" abstract="false" name="PercentOfRevenueFromContractWithCustomerExcludingAssessedTax" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="shc_UnderwritersMember" abstract="true" name="UnderwritersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_DebtInstrumentVariableRateFloor" abstract="false" name="DebtInstrumentVariableRateFloor" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="shc_DebtIssuanceCostsRefinancingAdditionalExpense" abstract="false" name="DebtIssuanceCostsRefinancingAdditionalExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_InterestRateCap1Member" abstract="true" name="InterestRateCap1Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_ToggleNotesDue2021Member" abstract="true" name="ToggleNotesDue2021Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_DefinedBenefitPlanServiceCost1" abstract="false" name="DefinedBenefitPlanServiceCost1" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="shc_AmortizationOfIntangibleAssetsNonproduction" abstract="false" name="AmortizationOfIntangibleAssetsNonproduction" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="shc_TermLoanAndSecondLienNotesMember" abstract="true" name="TermLoanAndSecondLienNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_SeniorNotesDue2023Member" abstract="true" name="SeniorNotesDue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_PeriodOfOptionToPurchase" abstract="false" name="PeriodOfOptionToPurchase" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="shc_ShareholdersEquityLineItems" abstract="true" name="ShareholdersEquityLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="shc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionNonvestedAggregateIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionNonvestedAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_NelsonFairfieldIncNelsonFairfieldMember" abstract="true" name="NelsonFairfieldIncNelsonFairfieldMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_DebtInstrumentMaximumNetLeverageRatioCovenant" abstract="false" name="DebtInstrumentMaximumNetLeverageRatioCovenant" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="shc_SegmentIncomeLoss" abstract="false" name="SegmentIncomeLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_EffectiveIncomeTaxRateReconciliationImpactOfRateChangesOnDeferredTaxBalances" abstract="false" name="EffectiveIncomeTaxRateReconciliationImpactOfRateChangesOnDeferredTaxBalances" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_LesseeOperatingandFinanceLeaseLiabilityPaymentsDueNextTwelveMonths" abstract="false" name="LesseeOperatingandFinanceLeaseLiabilityPaymentsDueNextTwelveMonths" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_LettersOfCreditSolvencyPaymentAsPercentOfMarketValue" abstract="false" name="LettersOfCreditSolvencyPaymentAsPercentOfMarketValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="shc_CapitalRestructuringBonuses" abstract="false" name="CapitalRestructuringBonuses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_CostAndExpensesCOVID19" abstract="false" name="CostAndExpensesCOVID19" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="shc_NetActuarialLossAmountExpectedToBeReclassifiedInTheNextTwelveMonthInAccumulatedOtherComprehensiveIncomeLoss" abstract="false" name="NetActuarialLossAmountExpectedToBeReclassifiedInTheNextTwelveMonthInAccumulatedOtherComprehensiveIncomeLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_RadioactiveIsotopeMember" abstract="true" name="RadioactiveIsotopeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="shc_UnrecognizedTaxBenefitsGrossReserve" abstract="false" name="UnrecognizedTaxBenefitsGrossReserve" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="shc_DerivativeNumberOfInstrumentsAmended" abstract="false" name="DerivativeNumberOfInstrumentsAmended" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="shc_AssetRetirementObligationNonCashGainLossFromDerecognition" abstract="false" name="AssetRetirementObligationNonCashGainLossFromDerecognition" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
