was significantly greater than its carrying value at October 31, 2014.  No impairment of goodwill occurred during the three  years ended December 31, 2014. Intangible assets  — Intangible assets include the value of core technology , trademarks and trade names, customer relationships  and intangible assets used in research and development activities. Core technology and customer relationships have definite  lives while intangible assets used in research and development activities and substantially all of our trademarks and trade  names have indefinite lives. Definite-lived intangible assets are amortized over their useful life using the straight-line method  of amortization and are periodically reviewed for impairment indicators.  Amortization of core technology is char ged to cost of  sales. Amortization of trademarks and trade names and customer relationships is char ged to amortization of intangibles.  Intangible assets used in research and development activities have an indefinite life until completion of the associated research  and development efforts. Upon completion of development, the assets are amortized over their useful life; if the project is  abandoned, the assets are written of f immediately. Indefinite-lived intangible assets are reviewed for impairment annually and  more frequently if impairment indicators exist. See Note 4 for more information about intangible assets. Tangible asset impairments  — We review the carrying value of amortizable long-lived assets for impairment whenever events  or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be  held and used is measured by a comparison of the carrying amount of the assets to the undiscounted future net cash flows  expected to be generated by the assets. If such assets are considered to be impaired, the impairment to be recognized is  measured by the amount by which the carrying amount of the assets exceeds their fair value.  Assets to be disposed of are  reported at the lower of their carrying amount or fair value less costs to sell and are no longer depreciated. Other long-lived assets and liabilities  — We discount our workers’ compensation and asbestos liabilities and the related  amounts recoverable from insurers by applying blended risk-free rates that are appropriate for the duration of the projected cash  flows. The use of risk-free rates is considered appropriate given that other risks af fecting the volume and timing of payments  have been considered in developing the probability-weighted projected cash flows.  The blended risk-free rates are revised  annually to consider incremental cash flow projections. Financial instruments  — The carrying values of cash and cash equivalents, trade receivables and short-term borrowings  approximate fair value. Notes receivable are carried at fair value, which considers the contractual call or selling price, if  applicable. Borrowings under our credit facilities are carried at historical cost and adjusted for principal payments and foreign  currency fluctuations. Derivative s — Foreign currency forward contracts and currency swaps are carried at fair value.  We enter into these contracts to  manage our exposure to the impact of currency fluctuations on certain foreign currency-denominated assets and liabilities and  on a portion of our forecasted purchase and sale transactions. Changes in the fair value of contracts treated as cash flow hedges are deferred and included as a component of other  comprehensive income (loss) (OCI) to the extent the contracts remain ef fective and the associated forecasted transactions  remain probable. Effectiveness is measured by using regression analysis to determine the degree of correlation between the  change in the fair value of the derivative instrument and the change in the associated foreign currency exchange rates. Deferred  gains and losses are reclassified to earnings in the same periods in which the underlying transactions af fect earnings. Changes  in the fair value of contracts not treated as cash flow hedges are recognized in earnings as those changes occur . Changes in the  fair value of contracts associated with product-related transactions are recorded in cost of sales while those associated with  non-product transactions are recorded in other income, net and are generally of fset by currency-driven gains or losses on the  underlying transactions. We may also use interest rate swaps to manage exposure to fluctuations in interest rates and to adjust  the mix of our fixed and floating rate debt.  We do not use derivatives for trading or speculative purposes and we do not hedge  all of our exposures. Environmental compliance and remediation  — Environmental expenditures that relate to current operations are expensed or  capitalized as appropriate. Expenditures that relate to existing conditions caused by past operations that do not contribute to our  current or future revenue generation are expensed. Liabilities are recorded when environmental assessments and/or remedial  efforts are probable and the costs can be reasonably estimated.  We consider the most probable method of remediation, current  laws and regulations and existing technology in determining our environmental liabilities. Pension and other postretirement defined benefits  — Net pension and postretirement benefits expenses and the related  liabilities are determined on an actuarial basis.  These plan expenses and obligations are dependent on management’ s  assumptions developed in consultation with our actuaries.  We review these actuarial assumptions at least annually and make  modifications when appropriate. With the input of independent actuaries and other relevant sources, we believe that the  47