ESDU A-Z Index: P-PIS

Linear Systems in Absence of Process Noise: least-squares minimisation including equation- and output-error methods, 87039; maximum likelihood method, 88011
Linear Systems in Presence of Process Noise: maximum likelihood method, 89032
Linear Systems (Lightly Damped) From Frequency Response Measurements, 90006, 93016: determination of initial values from approximation to Nyquist diagram, 90006, 93016
Use of Kalman Filter to Eliminate Measurement Noise, 88039

Parawings

see: Parachutes

Peening

see: Shot Peening

Percentile

Approximate Equations for Values in Normal Distribution, 91041
Estimation of Population Values for Normally-Distributed Variate: to specified confidence from sample mean, 91041
Point Estimate for Extreme-Value Distributions, 87034
Table of Values for Normal Distribution, 91017, 91041

Perfluoropolyalkyl Esters (pfpae)

see: Lubricants

Perforated Plates

see also: Acoustic Absorption Coefficient; Acoustic Impedance

Circular or Rectangular Holes: normal force, 70015; pressure drop across in compressible flow, 82009; pressure drop across in incompressible flow, 81039, 82009
Use to Improve Diffuser Performance: effect on static pressure recovery, 87015

Perforated-Wall Wind-Tunnels

see: Resonance in Wind-Tunnels; Wind-Tunnel Corrections for Aerofoils

Performance Analysis

see: Accelerometers; Aircraft Performance Analysis; Aircraft Performance Reduction; Axes Systems in Aircraft Dynamics and Performance; Flight Testing; Helicopter Performance Analysis

Performance Estimation

see: Aircraft Performance Estimation

Performance Measurement

see: Accelerometers; Aircraft Performance Analysis; Aircraft Performance Reduction; Anemometric Data Correction; Axes Systems in Aircraft Dynamics and Performance; Flight Testing; Helicopter Performance Analysis

Performance Reduction

see: Aircraft Performance Analysis; Aircraft Performance Reduction; Axes Systems in Aircraft Dynamics and Performance; Flight Testing; Helicopter Performance Analysis

Performance Series

Location of Items in ESDU Series, 99035
Record of Amendments to Items in ESDU Series, 99035

Persistence and Persistence Index

Definitions for Linear Systems, 67038

Petrol

see: Gasolines

Petroleum

see: Crude Petroleum; Fouling in Crude Oil Distillation Plant

Petroleum Gases

Dynamic Viscosity: temperature variation in liquid state, 66024
Kinematic Viscosity: temperature variation in liquid state, 66024, 71003

Petroleum Waxes

Density: typical values in liquid state, 71003
Dynamic Viscosity: typical values in liquid state, 71003
Kinematic Viscosity: typical values in liquid state, 71003

Phase Angle

Effective Phase Angle in Tyre-Friction Modelling, TM 176

Phase Margin

Linear Systems: definition, 74021, 80002

Phosphate Esters

see: Lubricants

Phosphating

see also: Wear Resistant Surface Coatings and Treatments

Rate of Formation of Case, 86040
Treatment Temperature, 86040
Use to Reduce Wear in Disc Cams, 94017

Phosphor-Bronze

Use as Hydrodynamic Bearing Material: guide to selection, 88018

Phugoid

Discussion of Desirable Characteristics for Good Aircraft Handling Qualities, 92006
Discussion of Origin and Characteristics, 86021
Influence of Aircraft Flexibility on, 96037
Requirements for Damping and for Speed Stability Characteristics: for military aircraft, 92006

Pinch Technology

see: Process Integration; Water Conservation in Process Plants

Pin Joints

see also: Linkages; Lugs (Fatigue Strength); Lugs (Static Strength); Lugs (Stress Concentration Factors); Lugs (Stress Intensity Factors)

Stress Concentration Factor Distribution Along Bore in Plate: plain hole loaded by pin, 93030

Pipe Bends

Stress Analysis

see: Pipe Bends (unrestrained); Pipe Bends (with End Flanges); Pipe Bends (with Straight Pipe Attachments)

With Internal Flow

see also: Forced Convection Heat Transfer; Noise in Air-Conditioning Duct Systems; Pressure Drop in Gas- or Vapour-Liquid Internal Flow; Pressure Drop in Internal Flow

design information on guide vanes, 83037

Pipe Bends (unrestrained)

Under In-Plane Bending and Pressure: change in bend angle, 74043; flexibility factors, 74043; maximum shear stresses, 74043

Pipe Bends (with End Flanges)

Under In-Plane Bending: change in bend angle, 81041; flexibility factors, 81041; maximum circumferential and longitudinal stresses, 81041

Pipe Bends (with Straight Pipe Attachments)

Under In-Plane Bending: change in bend angle, 75014; flexibility factors (and effect of short attachments or adjacent bends), 75014; maximum circumferential and longitudinal stresses, 75014

Pipes

Linings to Reduce Noise