Effect of the NACA Injection Impeller on the Mixture Distribution of a Double-Row Radial Aircraft Engine

The NACA injection impeller was developed to improve the mixture distribution of aircraft engines by discharging the fuel from a centrifugal supercharger impeller, thus promoting a thorough mixing of fuel and charge air. Tests with a double-row radial aircraft engine indicated that for the normal range of engine power the NACA injection impeller provided marked improvement in mixture distribution over the standard spray-bar injection system used in the same engine. The mixture distribution at cruising conditions was excellent; at 1200, 15OO, and 1700 brake horsepower, the differences between the fuel-air ratios of the richest and the leanest cylinders were reduced to approximately one-third their former values. The maximum cylinder temperatures were reduced about 30 [degrees] F and the temperature distribution was improved by approximately the degree expected from the improvement in mixture distribution. Because the mixture distribution of the engine tested improves slightly at engine powers exceeding 1500 brake horsepower and because the effectiveness of the particular impeller diminished slightly at high rates of fuel flow, the improvement in mixture distribution at rated power and rich mixtures was less than that for other conditions. The difference between the fuel-air ratios of the richest and the leanest cylinders of the engine using the standard spray bar was so great that the fuel-air ratios of several cylinders were well below the chemically correct mixture, whereas other cylinders were operating at rich mixtures. Consequently, enrichment to improve engine cooling actually increascd some of the critical temperatures. The uniform mixture distribution providod by the injection impeller restored the normal response of cylinder temperatures to mixture enrichnent

Building Better Interfaces for Remote Autonomous Systems

This 'Open Access' SpringerBrief provides foundational knowledge for designing autonomous, asynchronous systems and explains aspects of users relevant to designing for these systems, introduces principles for user-centered design, and prepares readers for more advanced and specific readings. It provides context and the implications for design choices made during the design and development of the complex systems that are part of operation centers. As such, each chapter includes principles to summarize the design implication that engineers can use to inform their own design of interfaces for operation centers and similar systems. It includes example materials for the design of a fictitious system, which are referenced in the book and can be duplicated and extended for real systems. The design materials include a system overview, the system architecture, an example scenario, a stakeholder analysis, a task analysis, a description of the system and interface technology, and contextualized design guidelines. The guidelines can be specified because the user, the task, and the technology are well specified as an example. Building Better Interfaces for Remote Autonomous Systems is for working system engineers who are designing interfaces used in high throughput, high stake, operation centers (op centers) or control rooms, such as network operation centers (NOCs). Intended users will have a technical undergraduate degree (e.g., computer science) with little or no training in design, human sciences, or with human-centered iterative design methods and practices. Background research for the book was supplemented by interaction with the intended audience through a related project with L3Harris Technologies (formerly Harris Corporation)

Building Better Interfaces for Remote Autonomous Systems

This 'Open Access' SpringerBrief provides foundational knowledge for designing autonomous, asynchronous systems and explains aspects of users relevant to designing for these systems, introduces principles for user-centered design, and prepares readers for more advanced and specific readings. It provides context and the implications for design choices made during the design and development of the complex systems that are part of operation centers. As such, each chapter includes principles to summarize the design implication that engineers can use to inform their own design of interfaces for operation centers and similar systems. It includes example materials for the design of a fictitious system, which are referenced in the book and can be duplicated and extended for real systems. The design materials include a system overview, the system architecture, an example scenario, a stakeholder analysis, a task analysis, a description of the system and interface technology, and contextualized design guidelines. The guidelines can be specified because the user, the task, and the technology are well specified as an example. Building Better Interfaces for Remote Autonomous Systems is for working system engineers who are designing interfaces used in high throughput, high stake, operation centers (op centers) or control rooms, such as network operation centers (NOCs). Intended users will have a technical undergraduate degree (e.g., computer science) with little or no training in design, human sciences, or with human-centered iterative design methods and practices. Background research for the book was supplemented by interaction with the intended audience through a related project with L3Harris Technologies (formerly Harris Corporation)

Soar-mode v5.0 User’s Manual for Soar release 5.2 and 6.0

Soar-mode is a major mode within the GNU-Emacs editor. It provides an integrated, structured editor for editing, running, and debugging Soar models on the production level. Productions are treated as first class objects. With keystroke (or menu) commands productions can be directly loaded, examined, and queried about their current match status. Listings of the productions that have fired or are about to fire can be automatically displayed. Soar-mode includes and organizes, for the first time, complete on-line documentation on Soar and a simple browser to examine this information

Towards Supporting Psychologically Plausible Variability in Agent-Based Human Modelling

We describe the initial steps in developing an agentbased cognitive architecture designed to support psychologically plausible human variability. The new architecture, COJACK, is based on JACK, a BDI-based agent language. It will constrain the agents to reason and act in a psychologically plausible manner. Their information processing will be adjusted by a set of parameters that moderate the agent's reasoning and actions, combined with a set of guidelines for developing plans and beliefs for the agents. This set of parameters will also support varying the agents' performance, both in terms of differences across agents as well as differences that arise within an individual due to internal and external factors. We conclude that other architectures will want to include a similar set, including representing a body, its interaction with the environment, and the passage of time

Distinguishing Cognitive Models of Spatial Language Understanding

Kluth T, Burigo M, Schultheis H, Knoeferle P. Distinguishing Cognitive Models of Spatial Language Understanding. In: Reitter D, Ritter FE, eds. Proceedings of the 14th International Conference on Cognitive Modeling (ICCM 2016). University Park, Pennsylvania, USA: Penn State; 2016: 230-231

Using a cognitive architecture to examine what develops

Different theories of development propose alternative mechanisms by which development occurs. Cognitive architectures can be used to examine the influence of each proposed mechanism of development while keeping all other mechanisms constant. An ACT-R computational model that matched adult behavior in solving a 21-block pyramid puzzle was created. The model was modified in three ways that corresponded to mechanisms of development proposed by developmental theories. The results showed that all the modifications (two of capacity and one of strategy choice) could approximate the behavior of 7-year-old children on the task. The strategy-choice modification provided the closest match on the two central measures of task behavior (time taken per layer, r = .99, and construction attempts per layer, r = .73). Modifying cognitive architectures is a fruitful way to compare and test potential developmental mechanisms, and can therefore help in specifying “what develops.

Transients Among Binaries with Evolved Low-Mass Companions

We show that stable disk accretion should be very rare among low-mass X-ray binaries and cataclysmic variables whose evolution is driven by the nuclear expansion of the secondary star on the first giant branch. Stable accretion is confined to neutron-star systems where the secondary is still relatively massive, and some supersoft white dwarf accretors. All other systems, including all black-hole systems, appear as soft X-ray transients or dwarf novae. All long-period neutron-star systems become transient well before most of the envelope mass is transferred, and remain transient until envelope exhaustion. This complicates attempts to compare the numbers of millisecond pulsars in the Galactic disk with their LMXB progenitors, and also means that the pulsar spin rates are fixed in systems which are transient rather than steady, contrary to common assumption. The long-period persistent sources Sco X-2, LMC X-2, Cyg X-2 and V395 Car must have minimum companion masses > 0.75 Msun if they contain neutron stars, and still larger masses if they contain black holes. The companion in the neutron-star transient GRO J1744-2844 must have a mass <0.87 Msun. The existence of any steady sources at all at long periods supports the ideas that (a) the accretion disks in many, if not all, LMXBs are strongly irradiated by the central source, and (b) mass transfer is thermally unstable in long-period supersoft X-ray sources.Comment: 10 pages, Latex, 1 ps figure, Ap.J., accepted Feb. 15, 199