In one embodiment, an apparatus includes a module having an array of transducers, and a heating element having multiple parts positioned proximate to the array of transducers. The multiple parts of the heating element are distinct from each other, where the multiple parts include a first part, a second part, and a third part. In addition, the first part includes a center portion and the second and third parts include a second portion and a third portion, respectively, and are positioned on opposite ends and a center portion positioned therebetween. The heating element is configured to produce more heat per unit length along the second and third portions at the opposite ends than in the center portion.