Concrete can be one of the most durable building materials and structures made of concrete can have a long service life. Consumption is projected to reach approximately 40 billion tons in 2017. Despite this the testing of concrete at all stages of its life cycle is still in its early stages although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Embodiments of the invention provide concrete suppliers, construction companies, regulators, architects, and others with rapid testing and performance data regarding the cure, performance, corrosion of concrete at different points in its life cycle based upon a simple electrical tests that remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment. Wireless sensors can be embedded from initial loading through post-cure into service life.

Ground surface comprising a substrate (110) having a Young's modulus of between 100 and 1000 GPa, and in which the ground surface has, on a working surface (120), a Vickers hardness of between 1300 and 10 000 kgf/mm.sup.2, and/or a surface coating forming the working surface, in which the surface coating contains amorphous carbon and/or titanium nitride and/or chromium nitride and/or tungsten carbide.

Concrete can be one of the most durable building materials and structures made of concrete can have a long service life. Consumption is projected to reach approximately 40 billion tons in 2017. Despite this the testing of concrete at all stages of its life cycle is still in its early stages although testing for corrosion is well established. Further many of the tests today are time consuming, expensive, and provide results only after it has been poured and set. Embodiments of the invention provide concrete suppliers, construction companies, regulators, architects, and others with rapid testing and performance data regarding the cure, performance, corrosion of concrete at different points in its life cycle based upon a simple electrical tests that remove subjectivity, allow for rapid assessment, are integrable to the construction process, and provided full life cycle assessment. Wireless sensors can be embedded from initial loading through post-cure into service life.

Disclosed is a gas sensing material for methylbenzene detection. Specifically, the gas sensing material includes a nanocomposite of Cr.sub.2O.sub.3 and ZnCr.sub.2O.sub.4. The content of Cr in the nanocomposite is from 67.0 at. % to 90.0 at. %, based on the sum of the contents of Cr and Zn atoms. The gas sensing material is highly selective to methylbenzenes over other gases and is highly sensitive to methylbenzenes. Also disclosed are methods for preparing the gas sensing material. The methods facilitate control over the composition of the gas sensing material and enable rapid synthesis of the gas sensing material at low temperature. Also disclosed is a gas sensor including the gas sensing material.

Fiber reinforced aerogel composites, including a transparent composite material that contains an aerogel and fibers embedded into the aerogel and/or bonded to one or more surfaces of the aerogel, and composites that contain an aerogel tile and an assemblage of fibers embedded into the aerogel tile or bonded to the aerogel tile that are useful as Cherenkov radiators for the detection and identification of subatomic particles. Also, methods of making and using the composites.

Fiber reinforced aerogel composites, including a transparent composite material that contains an aerogel and fibers embedded into the aerogel and/or bonded to one or more surfaces of the aerogel, and composites that contain an aerogel tile and an assemblage of fibers embedded into the aerogel tile or bonded to the aerogel tile that are useful as Cherenkov radiators for the detection and identification of subatomic particles. Also, methods of making and using the composites.

A simulated concrete mixture combines aggregate, sand, mortar clay, and additive. The mixture is hydrated with enough water or a hydrating solution to create a simulated concrete material having a desired slump. Useful aggregates include any type of aggregate used as a base for concretes, and useful additives include soaps, detergents, surfactants, and flocculants. The material can be refreshed with water or a refresher solution. The hydrating solution and refreshing solution are solution of water and additive. The simulated concrete material can be manipulated until its consistency becomes unworkable, after which it can be refreshed with water or refresher solution.

A manufacturing method of a big-model low-permeability microcrack core includes: (1) determining the size of a microcrack core to be manufactured; (2) placing stones in a baking oven to bake for 24h under 120 C., placing the stones into a mixer, mixing and spraying oil, enabling the oil to seep into the stone, evenly forming a thin oil film on stone's surface; (3) mixing the oil sprayed stone with quartz sand and cement, adding water to mix evenly to obtain cement paste; (4) spreading butter on core mold's inner surface to form a thin butter film, pouring the cement paste into the core mold to obtain a cement sample; (5) loading confining pressure outside the core according to the requirements of porosity and permeability of the mold to adjust a pore permeability value; (6) obtaining the big-model core with microcrack after the cement sample is dried and formed.

A manufacturing method of a big-model low-permeability microcrack core includes: (1) determining the size of a microcrack core to be manufactured; (2) placing stones in a baking oven to bake for 24 h under 120 C., placing the stones into a mixer, mixing and spraying oil, enabling the oil to seep into the stone, evenly forming a thin oil film on stone's surface; (3) mixing the oil sprayed stone with quartz sand and cement, adding water to mix evenly to obtain cement paste; (4) spreading butter on core mould's inner surface to form a thin butter film, pouring the cement paste into the core mould to obtain a cement sample; (5) loading confining pressure outside the core according to the requirements of porosity and permeability of the mould to adjust a pore permeability value; (6) obtaining the big-model core with microcrack after the cement sample is dried and formed.

It is provided a backing layer material resistant to temperature of up to about 600? C. comprising stainless steel powder, cement, water, and optionally at least one adjuvant, a ultrasonic transducer comprising said backing layer material conferring stability to the a ultrasonic transducer to temperature of up to about 600? C.