Abstract: A protective helmet system for protecting a user's head including outer and inner shells; a mat including a plurality of cells and a plurality of channels collectively defining a fluid flow system wherein each of the plurality of channels is structured and disposed for connecting adjacent ones of the plurality of cells such that each of the plurality of cells is in fluid flow communication; a fluid in the fluid flow system; and wherein a critical dampening occurs when a force impacts the outer shell at a point of impact causing the fluid to flow away from the point of impact thereby dampening at the point of impact as the fluid flows through the fluid flow system causing each of the plurality of cells on the opposing end of the mat to fill such that motion of the user's head away from the point of impact is decelerated.

Abstract: A radio communication control system for a lead unit and a plurality of remote units is disclosed. The system has a protocol for establishing a communication link between the lead unit and the one or more remote units in the system which prevents any of the units in that system from processing messages or commands from other units in other train systems or processing messages or commands originating from units within a train system which are addressed to other units within the system. The communication system also includes a communications channel contention system for minimizing the probability of multiple units transmitting on the common communication channel at the same time and for insuring that the highest priority communications in each train are transmitted first in time measured from the end of the latest transmission on the radio communications channel.

Abstract: A radio communication control system for a lead unit and a plurality of remote units is disclosed. The system has a protocol for establishing a communication link between the lead unit and the one or more remote units in the system which prevents any of the units in that system from processing messages or commands from other units in other train systems or processing messages or commands originating from units within a train system which are addressed to other units within the system. The communication system also includes a communications channel contention system for minimizing the probability of multiple units transmitting on the common communication channel at the same time and for insuring that the highest priority communications in each train are transmitted first in time measured from the end of the latest transmission on the radio communications channel.

Abstract: A radio communication control system for a lead unit and a plurality of remote units is disclosed. The system has a protocol for establishing a communication link between the lead unit and the one or more remote units in the system which prevents any of the units in that system from processing messages or commands from other units in other train systems or processing messages or commands originating from units within a train system which are addressed to other units within the system. The communication system also includes a communications channel contention system for minimizing the probability of multiple units transmitting on the common communication channel at the same time and for insuring that the highest priority communications in each train are transmitted first in time measured from the end of the latest transmission on the radio communications channel.

Abstract: A system for monitoring the performance of an internal combustion engine includes a pressure sensor that has a mounting configuration external to the cylinders such that it is capable of monitoring the pressures within two adjacent cylinders. The signal output of the sensor is filtered to remove undesired engine noise and blank out those signals which are unrelated to compression and firing, thereby reducing errors in the signal output. After filtering the signals to reduce noise, a successive number of samples related to compression and firing are obtained to provide an adequate number of signals which will average out mechanical and electrical noise. From the successive samples, a straight line approximation of the slope of the cylinder pressure curve, relative to crank angle, is obtained. The derived slope values are compared with upper and lower limits to determine whether or not the pressure within the engine cylinder of interest is acceptable.