PORTABLE BATTERY-POWERED INDUSTRIAL COMPUTER; PORTABLE BATTERY-POWERED DATA ACQUISITION SYSTEM FOR RESEARCH AND TESTING APPLICATIONS COMPRISED OF A COMPUTER, DATA ACQUISITION SOFTWARE, SIGNAL CONDITIONING FOR SENSORS AND ANALOG TO DIGITAL CONVERTER BOARD; PORTABLE BATTERY-POWERED AMUSEMENT PARK RIDE TESTER COMPRISED OF A COMPUTER, DATA ACQUISITION SOFTWARE, SIGNAL CONDITIONING FOR SENSORS AND ANALOG TO DIGITAL CONVERTER BOARD; PORTABLE BATTERY-POWERED POWER QUALITY TESTER