A substrate reinforcement or stiffener can be toolless, slide-on, slide-off, and removable. A hold down can carry pre-attached solder balls, solder units, or fusible elements. Fusible elements can be shaped to reduce thermal and mechanical stresses when reflowed onto a substrate. A heat-producing article can include a heat-dissipation material selectively located on, or immediately adjacent to, a heat-producing article. Clips with a plurality of fingers can be added to power conductors. Graphene strips, graphene coatings, or nanomaterials can be applied to electrically non-conductive articles and are able to selectively direct unwanted heat away from the heat-producing article. Electro-magnetic interference can be reduced by selective placement of voids in a shield of an electrical component.