Solid-State Sensor for Thermally Activated Magnetic and Resistive Aging

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Solution Overview

Problem

Existing methods for monitoring aging processes, such as in perishable items or engineering applications, fail to accurately account for variations in temperature and ambient conditions, leading to inaccurate determination of end-of-life dates.

Innovation Solution

A solid-state sensor using a composite structure with ferromagnetic nanoparticles in a non-ferromagnetic matrix, where the physical properties like electrical resistance or magnetization change with both time and temperature, allowing for more accurate monitoring of aging by detecting morphological changes and interactions within the sensor material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed time period from initial manufacture is used to determine end-of-life date, then the method is simple to implement, but it fails to account for variations in temperature or other ambient conditions during the lifetime

Engineering Contradiction:
Improvesimplicity of aging determination methodVSAvoidaccuracy of aging determination
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the parameter basis from simple time to a combined time-temperature parameter. The sensor material's physical property changes are monitored as a function of both time and temperature, allowing accurate determination of aging under varying ambient conditions while maintaining operational simplicity through automated sensing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/time-based aging determination method with a physical sensing mechanism. Instead of relying on chronological time tracking, the invention uses changes in physical properties (electrical resistance, magnetoresistance, or magnetization) of sensor material to detect aging, substituting a passive time-based system with an active physical measurement system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a solid-state sensor with temperature-dependent physical properties is used, then the accuracy of aging monitoring is improved, but the device complexity increases

Engineering Contradiction:
Improveaccuracy of aging and temperature monitoringVSAvoidcomplexity of sensor structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs composite sensor materials that combine ferromagnetic nanoparticles with a matrix material. This composite structure provides both temperature sensitivity and aging detection capabilities in a single integrated material system, achieving enhanced measurement precision without proportionally increasing device complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The sensor material serves multiple functions simultaneously: it acts as both the sensing element for aging detection and the temperature-dependent physical property indicator. The same material that changes properties due to aging also responds to temperature variations, eliminating the need for separate temperature sensors and reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If ferromagnetic nanoparticles are used in a non-ferromagnetic matrix, then the sensor can detect morphological changes through electrical resistance or magnetization changes, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedetection sensitivity of morphological changesVSAvoidprecision of nanoparticle distribution in matrix
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating regions with different ferromagnetic nanoparticle concentrations or sizes within the matrix. This allows the sensor to detect morphological changes through localized property variations, enhancing detection sensitivity while tolerating broader manufacturing variations in overall nanoparticle distribution.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables precise determination of aging thresholds, providing both time and temperature-dependent monitoring, which is essential for perishable items and industrial processes, improving the accuracy of expiration dates and process control.

Implementation Method 1

a physical property that varies as a function of both time and temperature... magnetization... Typically, the physical property changes faster with time as the temperature increases

Methodology Applied
Scientific EffectThermal demagnetization: Curie Point (ferromagnetic)

Implementation Method 2

thermally activated magnetic and resistive aging... nanoparticles, such as nanoflakes, of a first material, such as a ferromagnetic material

Methodology Applied
Scientific EffectMagnetic aging: Ferromagnetism

Implementation Method 3

the physical property may be electrical resistance... Morphological changes occur within the sensor material, causing an appreciable change in electrical conductivity

Methodology Applied
Scientific EffectElectrical resistance change: Electrical Resistance

Implementation Method 4

Morphological changes may reduce the magnetization of the solid-state material, which can be detected using a GMR (giant magnetoresistance) sensor

Methodology Applied
Scientific EffectGiant magnetoresistance: Magnetoresistance

Data Source

PatentEP2697660B1Thermally activated magnetic and resistive aging
Publication Date: 2019.03.20 INDIANA UNIVERSITY OF PENNSYLVANIA
  • EP2697660B1 patent drawingFigure 1~2
  • EP2697660B1 patent drawingFigure 3
  • EP2697660B1 patent drawingFigure 4A~4B

AI summary

Examples of the present invention include apparatus and methods for monitoring aging of an item. A solid-state structure is located within, adjacent to, or otherwise proximate the item, the solid-state structure including nanostructures. The electrical resistance and/or magnetization of the solid-state structure is determined to determine the degree of aging of the item. In representative examples, the solid-state structure includes nanostructures of a metal, such as a ferromagnetic metal, within a non-magnetic matrix, such as a semimetal, semiconductor, or insulator.