Abstract: A handheld work apparatus includes a tool and a brake unit for the tool. The brake unit includes a brake band and a brake drum. The brake band wraps around the brake drum. The brake unit is configured such that, during braking, a friction surface of the brake band is in contact with a friction surface of the brake drum, with the result that the brake band and the brake drum form friction partners. At least one of the friction surfaces is configured before a first braking operation on a wear layer, the thickness of the wear layer being from 0.5 ?m to 3 ?m or the thickness of the wear layer being from above 3 ?m to 20 ?m, and the wear layer containing Fe2O3 and/or FeO.

Abstract: The invention relates to a method for regenerating denox catalysts having an increased SO2/SO3 conversion rate as a result of the cumulation of iron compounds, and is characterized in that the catalysts are treated with an essentially aqueous acid solution, preferably having a pH between 0.5 and 4, and with an addition of antioxidants.

Abstract: The invention relates to a method for regenerating denox catalysts having an increased SO2/SO3 conversion rate as a result of the cumulation of iron compounds, and is characterized in that the catalysts are treated with an essentially aqueous acid solution, preferably having a pH between 0.5 and 4, and with an addition of antioxidants.

Abstract: The invention relates to a method for regenerating DeNOx catalysts having an increased SO2/SO3 conversion rate as a result of the cumulation of iron compounds, and is characterized in that the catalysts are treated with an essentially aqueous acid solution, preferably having a pH between 0.5 and 4, and with an addition of antioxidants.

Abstract: The invention relates to a method for regenerating DeNOx catalysts having an increased SO2/SO3 conversion rate as a result of the cumulation of iron compounds, and is characterized in that the catalysts are treated with an essentially aqueous acid solution, preferably having a pH between 0.5 and 4, and with an addition of antioxidants.

Abstract: The invention relates to a method for the regeneration of deNOx catalysts with a reduced activity caused by the accumulation of phosphor and phosphorous compounds. The method is characterized in that the catalysts are treated with an essentially aqueous solution of water-soluble alkaline reacting alkaline earth salts, ammonium hydroxide, or alkaline reacting ammonium salts, or water-soluble organic amines with an approximate pK value ranging between 2.5 and 5.5 and that the excess alkali is neutralized by subsequent treatment with inorganic or organic acids.