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Technical Paper

Zero-Waste PVD Cadmium for High Strength Steels
1998-11-11
983137
In spite of environmental issues related to cadmium and its electroplating process, electroplated cadmium is still extensively used in the aerospace and defense sectors. This trend is likely to continue especially for high strength steels because cadmium provides the best known corrosion and embrittlement protection for this application. Consequently, the environmental concerns related to the cadmium electroplating have been addressed using an alternative Zero-waste Physical Vapor Deposition (Z-PVD). This method does not use liquids, it recycles cadmium in situ, and is free of hydrogen embrittlement. The Z-PVD process is now in commercial production for the aerospace fasteners. The quality of the coatings has been at least equal to that of the electroplated cadmium.
Technical Paper

Zero-Gravity Testing of a Waste Management System
1969-02-01
690644
This paper describes the testing of a waste management system designed and fabricated for use in a space vehicle. The system provides for the collection and inactivation of urine, feces, emergency diarrheal disorders, vomitus, and debris; the volumetric determination of each micturition; and onboard storage of the inactivated wastes within the waste management system compartment. The zero-gravity test program conducted in a KC-135 aircraft provided the primary verification of the performance of the waste collection and urine volume determination functions prior to actual space flight. The test hardware simulated the actual system to a high degree of fidelity with respect to operational characteristics of the airflow required in collection, mechanical functions and system pressure differentials, in order to minimize simulation errors.
Technical Paper

Zero-G Water Selection Separator: A Performance Tradeoff
1969-02-01
690642
This paper presents a trade-off study to select a water separator system for a 3-man, 140-day, zero-g mission. Included is a summary of feasible concepts, a compilation of data on existing hardware, and a comparison of the performance characteristics of each with respect to the overall system. Six approaches to zero-g water separation were considered and are discussed: hydrophobic/hydrophilic screens; integrated condenser-water separators; centrifugal separators; cellular sponges; vortex separators; and elbow separators. Some of these techniques have high-performance characteristics with regard to water removal efficiency. However, when reduced to hardware, these same techniques may not integrate well with the overall system. The system selected was the integrated condenser-water-separator. This system requires no power, has no moving parts, and has a very small envelope.
Technical Paper

Zero-G Simulation using Neutral Buoyancy
1989-07-01
891529
For human beings who have been reared on the earth with its 1 G gravitational field, the condition of weightlessness is a world with which we are unfamiliar. Even if the layout and equipment configuration of a spacecraft designed to compensate for operation under Zero-G conditions, there are some things which are not effective under actual weightless conditions. In the design of a manned spacecraft, it is necessary to accumulate design data on human performance in a weightless condition, then to undertake design evaluations and verification under weightless conditions. In this paper, testing for the purpose of evaluating the effectiveness of Zero-G simulation using neutral buoyancy, conducted first of all in Japan, and recommendations on the equipment and Facilities required to conduct such simulations, are described.
Technical Paper

Zero Gravity and Life Support Systems — Friends or Foes?
1982-02-01
820837
Manned spacecraft life suport systems must operate in a zero gravity environment. Lack of the “pull” of gravity affects heat and mass transfer, fluid transport, phase change, and chemical and electrochemical processes. This paper covers new concepts necessary for humidity control, evaporative coolers, distillation units, and similar equipment required for spacecraft life support. Specific applications used on the Space Shuttle and in development for advanced regenerative systems are discussed, including how they work, how they are tested on earth, and how much, if at all, the weightless environment penalizes the designs.
Technical Paper

Zero Gravity Phase Separator Technologies - Past, Present and Future
1992-07-01
921160
Spacecraft life support equipment is often challenged with two phase flow, where liquid and gas exist together. In the zero gravity environment of an orbiting spacecraft, the behavior of a liquid/gas interface is dominated by forces not usually observed in one “G” due to the overwhelming effects of gravity. The normal perceptions no longer apply. Water does not run down hill and bubbles do not rise to the surface. Surface energy, capillary forces, wetting characteristics and momentum effects predominate. Techniques and equipment have been developed to separate the liquid/gas mixture into its constituent parts with various levels of efficiency and power consumption.
Standard

Zero Acceptance Number Sampling Procedures and Tables for Inspection by Attributes of A Continuous Manufacturing Process
2015-07-01
CURRENT
EIA584
Conventional attribute sampling plans based upon nonzero acceptance numbers are no longer desirable. In addition, emphasis is now placed on the quality level that is received by the customer. This relates directly to the Lot Tolerance Percent Defective (LTPD) value or the Limiting Quality Protection of MIL-STD-105. Measuring quality levels in percent nonconforming, although not incorrect, has been replaced with quality levels measured in parts per million (PPM). As a result, this standard addresses the need for sampling plans that can augment MIL-STD-105, are based upon a zero acceptance number, and address quality (nonconformance) levels in the parts per million range. This document does not address minor nonconformances, which are defined as nonconformances that are not likely to reduce materially the usability of the unit of product for its intended purpose.
Standard

ZINC PLATING
1991-10-01
HISTORICAL
AMS2402F
This specification covers the engineering requirements for electrodepositton of zinc and the properties of the deposit.
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