Abstract: A method and apparatus for testing network links bi-directionally and independently employ local test apparatus (1000) at one end of the link (1105, 1110, 1115) and remote test apparatus (1200) at the opposite end of the link. The local test apparatus transmits test traffic to the remote test apparatus which analyzes the test traffic to determine characteristics of the link in the local-to-remote direction. While the analysis is taking place, the remote test apparatus transmits interim test results to the local test apparatus, i.e., while the remote test apparatus is still running the test and without disrupting the test. Preferably, the remote test apparatus transmits test traffic to the local test apparatus which the latter analyzes to determine characteristics of the link in the remote-to-local direction. The local test apparatus may report the test results for both directions. The network may be a connected or connectionless network.

Abstract: A method and apparatus for testing network links bi-directionally and independently employ local test apparatus (1000) at one end of the link (1105, 1110, 1115) and remote test apparatus (1200) at the opposite end of the link. The local test apparatus transmits test traffic to the remote test apparatus which analyzes the test traffic to determine characteristics of the link in the local-to-remote direction. While the analysis is taking place, the remote test apparatus transmits interim test results to the local test apparatus, i.e., while the remote test apparatus is still running the test and without disrupting the test. Preferably, the remote test apparatus transmits test traffic to the local test apparatus which the latter analyzes to determine characteristics of the link in the remote-to-local direction. The local test apparatus may report the test results for both directions. The network may be a connected or connectionless network.

Abstract: A method, device and system for detecting the presence of microorganisms in an air sample taken from either a gaseous or liquid environment are described. The method including the steps of a) capturing with a filter microorganisms from the air sample; b) recovering from the filter with a liquid at least some microorganisms captured by the filter in step a); and c) detecting the presence of the at least some microorganisms in the liquid. The device and system include a chamber through which the air sample to be examined is circulated; a filter for capturing microorganisms susceptible to be present in the air sample; a liquid cooperating with the filter for recovering captured microorganisms therefrom; and a detector for detecting the presence of microorganisms in the liquid.

Abstract: A method, device and system for detecting the presence of microorganisms in an air sample taken from either a gaseous or liquid environment are described. The method including the steps of a) capturing with a filter microorganisms from the air sample; b) recovering from the filter with a liquid at least some microorganisms captured by the filter in step a); and c) detecting the presence of the at least some microorganisms in the liquid. The device and system include a chamber through which the air sample to be examined is circulated; a filter for capturing microorganisms susceptible to be present in the air sample; a liquid cooperating with the filter for recovering captured microorganisms therefrom; and a detector for detecting the presence of microorganisms in the liquid.

Abstract: A ground source heat pump system including an indoor fan coil, a high torque compressor, a thermostatic expansion valve (TXV), a suction gas distributor, an accumulator with an internal heat exchanger and an arrangement of check valves to permit a single direction of refrigerant flow in both the heating and cooling modes. Only one TX valve is required providing simplicity for the system. A backflooding control valve is used in the system to control condenser pressures to assure proper refrigerant quantity and pressure at the TX valve. The heat pump also uses a head pressure control valve to maintain a pre-set refrigerant pressure in the ground coil on air conditioning mode. The system charge is the same for heating and cooling and the ground coil consists of a plurality of three pipe units--one pipe for inflow and two for out flow.

Abstract: A braking system having a disk brake that is mechanically connected to at least one wheel of the vehicle and cooperates with a brake caliper that is actuated by a threaded rod screwed through a threaded connection in a control nut rotatively mounted inside the caliper body, the threaded connection being irreversible by axial forces alone. The brake linings are made of an elastomeric material having a high friction coefficient when the disk is not rotating. This system provides a compact parking brake having a high power and a large remote-indication capacity, and is particularly useful in railroad vehicles.

Abstract: Braking unit for vehicle, of the type comprising an axial actuating helical spring maintained in release position, against its elastic reaction force, through a screw-nut system rotatively driven by an electric motor, the spring acting upon the brake through the intermediary of a hydraulic master cylinder of which the piston is axially connected to an abutment ring of the spring also mechanically connected, via a screw-nut system to the rotor of an electric motor, such an unit being applied to a spring braking system for a vehicle possibly with a built-in park brake.

Abstract: A dual-piston hydraulic brake master cylinder includes a large hydraulic piston which supplies an initial large brake fluid volume and a small hydraulic piston which continues to supply brake fluid to the brakes when the large piston stops moving forward in its cylinder at higher brake pressures. The small, central hydraulic piston is connected to the end of a piston rod extension of a pneumatic booster piston. The large piston surrounds the small piston and opens a reservoir line tilt-valve in the piston retracted position. A passageway between the large and small hydraulic chambers is open in the retracted position to allow communication of braking fluid therebetween. During brake actuation a seal arrangement interrupts this communication. The large and small hydraulic chambers supply the brake circuits through delivery passages.

Abstract: A brake cylinder device combining a pneumatically-applied service brake and a spring-applied parking brake in a compact unit made possible by limiting the stroke of the parking brake piston to minimize the expansion of the spring and thus the amount of force relaxation, so that a relatively small spring may be used. The service brake piston carries a threaded shaft on which a nut is rotatably carried for locking engagement with the parking brake piston.

Abstract: A dynamic/friction brake blending valve device having a piston assembly arranged to operate a pressure regulator via which brake cylinder pressure is controlled. Associated with the relay valve device is an electrical circuit comprising a differential amplifier subject in a first mode of operation to a brake command signal and a dynamic brake signal representing the degree of dynamic brake effort being provided in response to the brake command. An error signal resulting from comparison of the brake command and dynamic brake signals is converted by a transducer to a corresponding fluid pressure that is supplied to a chamber formed between first and second differential pistons of the piston assembly to actuate the pressure regulator and thereby produce brake cylinder pressure corresponding to the deficiency of the dynamic brake.