Abstract: There is provided an asymmetric integrally skinned membrane comprising a polyimide and another polymer selected from the group consisting of polyvinylpyrrolidone, sulfonated polyetheretherketones and mixtures thereof. The membrane which is substantially insoluble in an organic solvent and substantially defect-free can be useful as a separation membrane.

Abstract: There is provided an asymmetric integrally skinned membrane comprising a polyimide and another polymer selected from the group consisting of polyvinylpyrrolidone, sulfonated polyetheretherketones and mixtures thereof. The membrane which is substantially insoluble in an organic solvent and substantially defect-free can be useful as a separation membrane.

Abstract: There is provided an asymmetric integrally skinned membrane comprising a polyimide and another polymer selected from the group consisting of polyvinylpyrrolidone, sulfonated polyetheretherketones and mixtures thereof. The membrane which is substantially insoluble in an organic solvent and substantially defect-free can be useful as a separation membrane.

Abstract: A portable personal security device of compact size capable of being carried in a pocket or purse or the like, has a pistol-like configuration with a handgrip portion and a barrel portion. The device includes a noxious chemical which may be discharged to fend off an attack by an assailant, and an audible alarm which may be sounded to attract attention and/or to discourage an attacker. Further, a light is provided on the device so that it can be used as a flashlight. A plurality of finger-receiving openings are formed in the handgrip portion to effect a secure grip on the device and make it difficult to dislodge from the hand of the user. These openings also assist in quickly and properly orienting the device. An actuator for energizing the light, the chemical discharge and the audible alarm includes structure which enables sequential activation of these devices.