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- Andersson, Kent, 1967-
(författare)
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On the Military Utility of Spectral Design in Signature Management : a Systems Approach
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is an ongoing duel between military sensor development and developments in signature management. The last decade, with warfare characterized by joint expeditionary operations and asymmetry, has favored sensors. However, on account of the worsening security situation in Europe, there is now also an increasing interest in efforts to increase survivability of own military platforms. Spectral design is one of several promising technologies with extensive research potentially suitable for Low Observable platforms. It involves creating desired spectral optical responses from surfaces, in this case reducing contrast to background, by choosing suitable materials and structures. The challenge to a military decision-maker, faced with inherent uncertainties concerning the future and with limited resources, is how to choose among alternative capabilities, technologies or equipment. Correspondingly, on account of the system character of the signature attribute, researchers in technologies for signature management has difficulties communicating relevant basis for these decisions. The scope of this thesis is therefore to find and analyze patterns in decision situations involving technology or technical systems for military use, and the purpose is to propose conceptual and methodological contributions to support future decisionmaking. The technology focus is on spectral design and the application in focus is signature management of Low Observable military platforms. The research objective is addressed from a military system and capability centric perspective using methods from several disciplines in the military sciences domain. The result is synthesized from four separate studies: 1) on spectral design using systematic review of literature, 2) on military utility using a concept formation method, 3) on modeling for how to operationalize a link between spectral design and measures of military utility using methods of military operations research, and, 4) on cases of systems engineering of military Low Observable platform designs. In summary, the result of the work presented in this thesis is a compilation of related work in military sciences, systems engineering and material optics into a framework to support effective decision-making in relevant contexts. The major contribution to theory is a proposed concept called Military Utility, capturing how to communicate the utility of technical systems, or technology, in a military context. It is a compound measure of Military Effectiveness, Military Suitability and Affordability. Other contributions can be expected to support decision-making in practice; - the so-called Ladder-model is a template for how to quantitatively operationalize the military effectiveness dimension of Military Utility regarding the use of spectral design; - an applied Ladder-model is demonstrated, useful for analyzing the military utility of spectral designs in Low Observable attack aircraft; - a probabilistic framework for survivability assessments is adopted into a methodology for doing the analysis, and lastly; - a generic workflow is identified, from relevant development programs, including decision-situations that can benefit from the adopted methodology.
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| 2. |
- Lundström, Ingemar, et al.
(författare)
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Recent developments in field-effect gas sensors
- 1995
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 23:2-3, s. 127-133
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Tidskriftsartikel (refereegranskat)abstract
- Some of the ongoing studies at our laboratory of gas-sensitive field-effect devices with catalytic metal gates are reviewed. More particularly, we discuss the use of such devices in so-called electronic noses due to the possibility of changing the selectivity patterns of the devices by the choice of catalytic metal and operation temperature. Several examples of the application of electronic noses consisting of field-effect devices in combination with metal oxide-based sensors are given. Finally, a summary is given of some remaining scientific problems and studies related to the understanding and development of gas-sensitive field-effect devices.
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| 6. |
- Åkerlind, Christina, 1974-
(författare)
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Optical Studies of Bio-inspired Materials for Camouflage
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the ongoing sensor-camouflage duel, new functionalities and sensing abilities are continuously incorporated in detector devices, requiring new capabilities on the camouflage side. The aim of this work is to contribute to improved camouflage including low polarization detectability in wavelength regions with both visible and invisible light. To find new surfaces that can be used as camouflage, we seek for materials that in a spectral design perspective meet the requests of military utility. We have represented this with a 'ladder model' which step by step connects the system and requirements aspects from a basic material level to a useful application.The focus in this study is mainly on the first rungs of the 'ladder' which are addressing aspects of spectral design and systems engineering as well as requirements of camouflage materials. We have stated six criteria for evaluating camouflage materials and their interactions with light. The criteria are related to reflection, gloss, degree of polarization, emissivity, broadband and dynamic properties.The included papers can be divided into two parts. The first part is related to aspects of the evaluation criteria for camouflage and the second part presents studies of bio-inspired materials and their performance related to the evaluation criteria.In connection with the presentation of the 'ladder model' for military utility and the six criteria for camouflage, several materials divided into the four categories: pigments, thin film coatings, multidimensional structures and metamaterials are surveyed. We also studied higher system design levels evaluating the visual and thermal contrast by inspecting images of an object's surface in a background. Important terms and parameters at this level were detectability and the lightness of a color. Furthermore a literature review of polarimetric environmental background properties was performed together with a reference materials study.Camouflage properties of several organic material surfaces have been studied. The biopolymeric materials range from beetle cuticle to cellulose based foams and protein fibres. In addition to white structures, we also investigated dynamic properties and initiated work using organic dyes to expand the use of the studied materials to camouflage applications. The main characterization techniques were reflection spectrometry, scatterometry and Mueller-matrix ellipsometry. These methods were used with an aim to mainly investigate the first three camouflage criteria (reflection, gloss, degree of polarization) but also touching on emissivity and dynamic coloring. Overall, the academic approach have been balanced with the requests and limits given by the military utility. The results will contribute to better camouflage by using advanced bio-inspired materials.
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| 7. |
- Åkerlind, Christina
(författare)
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Optical Studies of Materials for Spectral Design
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Optical material properties have been studied in a wide wavelength range. Theaim is future use of spectral design for camou age. The main characterization techniques used in this work are Refection Spectroscopy, Scatterometry (BRDF) and Mueller Matrix Ellipsometry. Six camouflage evaluation criteria based on reflection, emissivity, polarization, gloss, dynamic coloring and broadband properties, are to a greater or lesser degree related to the interaction between light and materia. Almost all are connected to the work of this thesis and are exemplied through dierent material categories with potential for use in camouföage applications. The included papers presents: a broad band (visible-infrared-microwave) study, two examples of dynamic optical properties of thin lms, and polarization and scattering properties of a natural surface.
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| 8. |
- Åkerlind, Christina, et al.
(författare)
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Scattering and Polarization Properties of the Scarab Beetle Cyphochilus insulanus cuticle
- 2015
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 54:19
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Tidskriftsartikel (refereegranskat)abstract
- Optical properties of natural photonic structures can inspire material developments in diversified areas, such as the spectral design of surfaces for camouflage. Here, reflectance, scattering, and polarization properties of the cuticle of the scarab beetle Cyphochilus insulanus are studied with spectral directional hemispherical reflectance, bidirectional reflection distribution function (BRDF) measurements, and Mueller-matrix spectroscopic ellipsometry (MMSE). At normal incidence, a reflectance (0.6–0.75) is found in the spectral range of 400–1600 nm and a weaker reflectance <0.2 in the UV range as well as for wavelengths >1600 nm . A whiteness of ?=42 is observed for mainly the elytra of the beetle. Chitin is a major constituent of the insect cuticle which is verified by the close similarity of the measured IR spectrum to that of ? -chitin. The BRDF signal shows close-to-Lambertian properties of the beetle for visible light at small angles of incidence. From the MMSE measurement it is found that the beetles appear as dielectric reflectors reflecting linearly polarized light at oblique incidence with low gloss and a low degree of polarization. The measured beetle properties are properties that can be beneficial in a camouflage material.
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| 9. |
- Åkerlind, Christina, et al.
(författare)
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Spectroscopic ellipsometry and vector network analysis for determination of the electromagnetic response in two wavelength regions
- 2008
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Ingår i: Physica Status Solidi. C: Current Topics in Solid State Physics. - Weinheim, Germany : Wiley-VCH Verlagsgesellschaft. - 1862-6351. ; 5:5, s. 1089-1092:5, s. 1089-1092
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Tidskriftsartikel (refereegranskat)abstract
- In this work, spectroscopic ellipsometry and vector network analysis are used to determine the electromagnetic response of three samples, an epoxy polymer, a sample with ferrit-based nanoparticles in a polymer matrix and silicon, in the wavelength ranges 0.4-30 μm and 0.75-7.59 cm. Both methods measure amplitude and phase changes due to interaction with a sample and can be used to measure the full complex-valued dielectric response to electromagnetic radiation. The data from the two methods show similar levels of the response at the two ends of the spectral gap between the ranges of the two methods.
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| 10. |
- Akerlind, C, et al.
(författare)
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Optical properties and switching of a Rose Bengal derivative: A spectroscopic ellipsometry study
- 2011
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Ingår i: THIN SOLID FILMS. - : Elsevier Science B.V., Amsterdam.. - 0040-6090. ; 519:11, s. 3582-3586
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Tidskriftsartikel (refereegranskat)abstract
- Optical properties in terms of the complex-valued dielectric function were determined for spin-coated films of a Rose Bengal derivative using variable angle of incidence spectroscopic ellipsometry in the visible and infrared wavelength regions. In addition, the thickness and roughness of the films were determined and related to the solution concentration of Rose Bengal. Switching between two different oxidation states of the Rose Bengal derivative was investigated. The two states were chemically induced by exposure to vapors of hydrochloric acid and ammonia, respectively. A substantial and reversible change of the optical properties of the films was observed.
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