Abstract: An apparatus for measuring the size distribution of particles by making use of centrifugal force field, comprising a mechanism for making a suspension revolve, an optical unit for detecting a light absorption by the suspension, and a micro-computer. The suspension suspends test particles whose size distribution is to be measured. The optical unit measures a time-dependent particle concentration variation due to the particle movements forced in a centrifugal force field produced by the revolution of the suspension. The micro-computer is provided with a memory for storing equations to obtain the size distribution of particles from the measured particle concentration variation and equations for correcting adverse effects by non-parallel particle movements in a centrifugal force field, to give a particle size distribution free from the error arising from the non-parallel movements of particles.

Abstract: A pipet cleaning apparatus in which cleaning liquid is fed into a cleaning tank, where a pipet is accommodated, through a feeding pipe line, a liquid level in the tank is raised to the full liquid level to immerse the pipet in the cleaning liquid, then the used cleaning liquid is overflown through an overflow portion of a discharging pipe line and by repeating the same process, the pipet cleaning is carried out, characterized in that the cleaning liquid is detected by a sensor at a level lower than the full liquid level by each cleaning time, the detected signal is counted by a counter, and when a preset number of cleaning times is counted, a valve of the feeding pipe line is closed.

Abstract: A method and an apparatus for testing the quality of ready-mixed concrete. The present invention enables the water-to-cement ratio in ready-mixed concrete to be measured quickly and precisely through the measurement of the weight and underwater weight of mortar extracted from the ready-mixed concrete whose quality is to be examined.

Abstract: There is disclosed an electronic counting scale provided with means for calculating a maximum addable number of items to be added to an already counted known number of items with an error being eliminated from the counted number of a total items including the added items, said means calculating the maximum addable number on the basis of the standard variation of an average weight estimated from the samples taken from the entire population of the items to be counted.

Abstract: An electronic balance includes a weighing means for producing digital output signals as a measured value in response to a force induced upon a tray, a first memory for storing the mass of a reference weight, a discriminator for signalizing the existence and non-existence of an object on the tray, a second memory for storing a corrected value obtained by differentiating between a measured value of the reference weight and the mass stored in the first memory when the discriminator signalizes that no object is placed on the tray, an arithmetic unit for correcting a measured value signalized by the weighing means in accordance with the corrected value stored in the second memory when the discriminator signalizes that an object exists on the tray, and an output unit for permitting of visual inspection of the arithmetic results obtained by the arithmetic unit.

Abstract: A weighing balance to provide an average weight to an object which tends to move while being weighed such as a laboratory animal. The object to be weighed is placed on a receiving pan which provides an electrical analog output signal corresponding to the weight of the object. This signal after passing through an amplifier is converted to a digital electrical signal fed to a data input control means. A level detector setting means allows an output from said control means only when the weight on the balance reaches a predetermined level. The output from the control means is fed to a memory having a plurality of registers which store this information. Coupled on one side to this memory is a comparator which is also coupled on a second side to said control means. Also coupled to said comparator means is an allowable range means, sampling time means, and average calculating means. The average calculating means feeds an output to a printer.