An electrical filter is disclosed. The electrical filter can include a conductive concrete structure including at least one of a conductive carbon material, a magnetic material, or a conductive metallic material. The conductive concrete structure is characterized by an electrical conductivity greater than 0.5 siemens per meter. The electrical filter also includes at least one electrical cable disposed within the conductive concrete structure. The at least one electrical cable includes an input to receive an electrical signal and an output to output an attenuated electrical signal.

In some implementations, a conductive concrete composition for providing improved shielding against electromagnetic radiation comprises cement, one or more supplementary materials, aggregates, one or more carbon products, and fibers. In some implementations, the composition comprises between about 5% and about 40% by weight of cement, between about 1% and about 20% by weight of one or more supplementary materials, between about 5% and about 80% by weight of aggregates, between about 1% and about 40% by weight of one or more carbon products, and between about 1% and about 10% by weight of fibers. In some embodiments, the one or more supplementary materials comprises ground granulated blast furnace slag (GGBS), the one or more carbon products comprises graphite, and the fibers comprise steel fibers. The aggregates can include normal weight, lightweight, and/or fine aggregates.

In some implementations, a conductive concrete composition for providing improved shielding against electromagnetic radiation comprises cement, one or more supplementary materials, aggregates, one or more carbon products, and fibers. In some implementations, the composition comprises between about 5% and about 40% by weight of cement, between about 1% and about 20% by weight of one or more supplementary materials, between about 5% and about 80% by weight of aggregates, between about 1% and about 40% by weight of one or more carbon products, and between about 1% and about 10% by weight of fibers. In some embodiments, the one or more supplementary materials comprises ground granulated blast furnace slag (GGBS), the one or more carbon products comprises graphite, and the fibers comprise steel fibers. The aggregates can include normal weight, lightweight, and/or fine aggregates.

Doped titanium niobate is provided, which has a chemical structure of Ti.sub.(1-x)M1.sub.xNb.sub.(2-y)M2.sub.yO.sub.(7-z)Q.sub.z or Ti.sub.(2-x)M1.sub.xNb.sub.(10-y)M2.sub.yO.sub.(29-z)Q.sub.z, wherein M1 is Li, Mg, or a combination thereof; M2 is Fe, Mn, V, Ni, Cr, or a combination thereof; Q is F, Cl, Br, I, S, or a combination thereof; 0x0.15; 0y0.15; 0.01z2; 0x0.3; 0y0.9; and 0.01z8.

The present disclosure provides compositions comprising modified biochar and a cement composition, as well as methods of making and characterizing such compositions, and/or technologies relating to such compositions, their production, and/or their use.