<?xml version="1.0" encoding="utf-8"?>
<!--
Taxonomy based on XBRL standard Version 2.1.
Created by UBmatrix Taxonomy Designer 3.0.3.2433 (2009-05-15 09:36).  
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Copyright (c) 2002-2010 UBmatrix inc., All Rights Reserved
Produced on 2010-10-05 07:10:08
-->
<schema
  xmlns="http://www.w3.org/2001/XMLSchema"
  xmlns:xbrli="http://www.xbrl.org/2003/instance"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xyz="http://www.xyz.com/2010-12-31"
  xmlns:dei="http://xbrl.us/dei/2009-01-31"
  xmlns:xbrldt="http://xbrl.org/2005/xbrldt"
  targetNamespace="http://www.xyz.com/2010-12-31"
  elementFormDefault="qualified"
  attributeFormDefault="unqualified">
  <annotation>
    <appinfo>
      <link:roleType
        roleURI="http://www.xyz.com/role/DocumentInformation"
        id="DocumentInformation">
        <link:definition>1200 - Document - Document Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType
        roleURI="http://www.xyz.com/role/AccountingPolicies"
        id="AccountingPolicies">
        <link:definition>1301 - Disclosure - Accounting Policies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType
        roleURI="http://www.xyz.com/role/InventoryByComponent"
        id="InventoryByComponent">
        <link:definition>1302 - Disclosure - Inventory, By Component</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType
        roleURI="http://www.xyz.com/role/LossContingencyAccrual"
        id="LossContingencyAccrual">
        <link:definition>1303 - Disclosure - Loss Contingency Accrual</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType
        roleURI="http://www.xyz.com/role/NonmonetaryTransactions"
        id="NonmonetaryTransactions">
        <link:definition>1304 - Disclosure - Nonmonetary Transactions</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:type="simple"
        xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef"
        xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"
        xlink:href="xyz-20101231_pre.xml"
        xlink:title="Presentation Links, all" />
      <link:linkbaseRef xlink:type="simple"
        xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef"
        xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"
        xlink:href="xyz-20101231_def.xml"
        xlink:title="Definition Links, all" />
      <link:linkbaseRef xlink:type="simple"
        xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef"
        xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"
        xlink:href="xyz-20101231_lab.xml"
        xlink:title="Label Links, all" />
      <link:linkbaseRef xlink:type="simple"
        xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef"
        xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase"
        xlink:href="xyz-20101231_cal.xml"
        xlink:title="Calculation Links, all" />
    </appinfo>
  </annotation>
  <import
    namespace="http://www.xbrl.org/2003/instance"
    schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <import
    namespace="http://xbrl.org/2005/xbrldt"
    schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <import
    namespace="http://xbrl.us/us-types/2009-01-31"
    schemaLocation="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-types-2009-01-31.xsd" />
  <import
    namespace="http://xbrl.us/us-gaap-std/2009-01-31"
    schemaLocation="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-std-2009-01-31.xsd" />
  <import
    namespace="http://xbrl.us/dei-std/2009-01-31"
    schemaLocation="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-std-2009-01-31.xsd" />
  <import
    namespace="http://www.xbrl.org/2003/linkbase"
    schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <element
    id="xyz_AccountingPoliciesHierarchy"
    name="AccountingPoliciesHierarchy"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_AccountingPoliciesLineItems"
    name="AccountingPoliciesLineItems"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_AccountingPoliciesTable"
    name="AccountingPoliciesTable"
    type="xbrli:stringItemType"
    substitutionGroup="xbrldt:hypercubeItem"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_DocumentInformationHierarchy"
    name="DocumentInformationHierarchy"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_InventoryByComponentLineItems"
    name="InventoryByComponentLineItems"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_InventoryByComponentRollUp"
    name="InventoryByComponentRollUp"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_InventoryByComponentTable"
    name="InventoryByComponentTable"
    type="xbrli:stringItemType"
    substitutionGroup="xbrldt:hypercubeItem"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_LossContingencyAccrualCarryingValuePeriodIncreaseDecreaseRollUp"
    name="LossContingencyAccrualCarryingValuePeriodIncreaseDecreaseRollUp"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_LossContingencyAccrualLineItems"
    name="LossContingencyAccrualLineItems"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_LossContingencyAccrualTable"
    name="LossContingencyAccrualTable"
    type="xbrli:stringItemType"
    substitutionGroup="xbrldt:hypercubeItem"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
  <element
    id="xyz_NonmonetaryTransactionHierarchy"
    name="NonmonetaryTransactionHierarchy"
    type="xbrli:stringItemType"
    substitutionGroup="xbrli:item"
    xbrli:periodType="duration"
    abstract="true"
    nillable="true" />
</schema>