Dust collectors with bag filters are widely used to remove hazardous aerosols in work environments. Package type dust collectors, which include a fan and motor, differ in a wide variety of ways, such as the inner structure, the filter media, methods for cleaning collected dust, and flow control methods. In this study we focus on the performance of dust collectors for respirable dust fraction, which can reach the lung alveoli and cause pneumoconiosis. We surveyed the actual situation of dust collectors at worksites by means of light scattering photometers with PM2.5 cyclones, measured the details of performance of a typical dust collector using common test dust (Atomite) in a laboratory, and then tested the collection efficiency of the filter samples with and without dust load. The test aerosols for the filter samples were generated by the nebulization of standard monodisperse particles (Polystyrene latex particles, 0.6 to 3 μm). The penetration measured by photometers with PM2.5 cyclones approximated the performance of dust of 1.2 μm in nominal size. We propose the test methods at worksites and the filter media of bag filters in confirming the performance of dust collectors.

A continuous direct compression process for a low-dose drug product was proposed. Acetaminophen was used for the model drug, and the mixing and tableting experiments with the low content were conducted using direct compression continuous manufacturing system. A low-dose continuous mixing was conducted in two steps. It was found that it is important to select the similar particle size for both drug and excipient in the first step mixing, and the result of the tableting experiment, the tablet contained 1% API indicated the good content uniformity. The experimental result of the second step, it was difficult to obtain the tablet contained 0.01% API with the good content uniformity. It was suggested that it is important to use jet-milled drug instead of using non-pulverized drug in the second step.

In order to elucidate the enhancement mechanism of corrosion resistance of galvanized steels in different exposure environments, influence of anions and metal ions on the formation, structure and morphology of zinc rust of basic zinc salt (BZS) particles was investigated. The structure of BZS is dependent of the stability of Zn²⁺-complexes with anions and the effect is in order of SO₄²⁻ > Cl⁻ >> NO₃⁻. Therefore, SO_X and air-borne chloride markedly affect the rust formation in atmospheric corrosion of galvanized steels. Also, the BZS rust particles were synthesized in the presence of Ni(II) and Ti(IV) to clarify the role of alloying Ni and Ti with zinc coating on the formation of zinc rust. Addition of these metal ions strongly suppresses the crystallization and growth of BZS rust particles. Accordingly, alloying Ni and Ti in galvanized steel would form the dense and compact zinc rust layer on the steel, leading to the suppression of further corrosion of steel.