Abstract: A contaminant detector includes a detection object that is inclined relative to a horizontal direction in a drainage unit for accumulation of discharged water and on which a contaminant is to be deposited and a detection unit configured to emit energy toward the detection object to detect a contamination state of the detection object. The detection unit includes a transmission and reception module configured to emit and receive energy, a calculation module configured to calculate an amount of energy received from the detection object by the transmission and reception module, and a determination module configured to determine, based on the amount of energy calculated by the calculation module, the contamination state of the detection object.

Abstract: A storage water heater is provided that allows for improved maintenance of hygiene in a lower part of a hot-water storage tank and in a passage connected to the lower part of the hot-water storage tank. A storage water heater includes a heating device, a hot-water storage tank, a first passage, and a controller. The hot-water storage tank stores hot water. The first passage is connected to a lower part of the hot-water storage tank. The controller is configured to selectively switch between a heat-up operation and a recirculation operation. In the heat-up operation, hot water heated by the heating device is delivered to an upper part of the hot-water storage tank. In the recirculation operation, hot water flowing out from the upper part of the hot-water storage tank is delivered to the lower part of the hot-water storage tank via the first passage.

Abstract: A humidity sensor includes a sound wave element configured to transmit a sound wave and receive the sound wave reflected by a reflector, a reception circuit configured to obtain an arrival time of the reflected wave received by the sound wave element, and a humidity analysis circuit configured to calculate humidity by using the arrival time, a distance from the sound wave element to the reflector, and a temperature of a space from the sound wave element to the reflector.

Abstract: A humidity sensor includes a sound wave element configured to transmit a sound wave and receive the sound wave reflected by a reflector, a reception circuit configured to obtain an arrival time of the reflected wave received by the sound wave element, and a humidity analysis circuit configured to calculate humidity by using the arrival time, a distance from the sound wave element to the reflector, and a temperature of a space from the sound wave element to the reflector.

Abstract: In a photocatalyst and a photocatalyst carrier, tungsten oxide microcrystals that have a crystal grain size of 10 nm or less and oxidizes a gaseous chemical substance and titanium oxide microcrystals that have a crystal grain size of 10 nm or less and oxidizes the gaseous chemical substance are irregularly arranged to form a solid.

Abstract: In a photocatalyst and a photocatalyst carrier, tungsten oxide microcrystals that have a crystal grain size of 10 nm or less and oxidizes a gaseous chemical substance and titanium oxide microcrystals that have a crystal grain size of 10 nm or less and oxidizes the gaseous chemical substance are irregularly arranged to form a solid.