| 1. |
- Ashraf, Shakeel, 1984-, et al.
(författare)
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Determination of complex refractive index of SU-8 by Kramers-Kronig dispersion relation method at the wavelength range 2.5 – 22.0 μm
- 2019
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 224, s. 309-311
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Tidskriftsartikel (refereegranskat)abstract
- Accurate determination of the complex refractive index of SU-8 epoxy has significant for the wide variety of applications in optical sensor technology at IR range. The complex refractive index of SU-8 is determined by recording the transmission of light spectra for the wavelength range of 2.5 – 22.0 μm. The data analysis is based on the Kramers-Kronig dispersion relation method. The method has several merits, such as ease of operation, non-contact technique, measurement accuracy, and rapid measurement. The present method is not restricted to the case of SU-8 but it is also proposed to be applicable across a broad range of applications, such as assessment of the optical properties of paints and biomedical samples.
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| 2. |
- Niskanen, Ilpo, et al.
(författare)
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Determination of relative solids concentration in homogeneous dual component pulp-filler suspension by multi-spectrophotometer
- 2020
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 35:1, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- The concentration of fibers and fillers in the pulp suspension is an important parameter in the monitoring process. This paper proposes a versatile optical measurement system to estimate the concentration of a solids mixture in water. The geometry used in a multi-spectrophotometer (MSM) enables the controlled observation of transmission, and forward scattering light from the suspension in the UV-visible spectral range. We have developed the new fibers mixing system which gives a homogenous distribution of the fines and fillers making it possible to increase the reproducibility and accuracy of the measurement. The data analysis is based on the Beer-Lambert law and CIELAB color space equations. The results show that the proposed method is accurate for measuring the fines and filler concentrations in multicomponent suspensions.
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| 3. |
- Niskanen, Ilpo, et al.
(författare)
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Determining the complex refractive index of cellulose nanocrystals by combination of Beer-Lambert and immersion matching methods
- 2019
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 235, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Nanocelluloses have received significant interest due to their unique structural, mechanical, and optical properties. Nanocellulose refractive indices can be used to indicate many crucial characteristics, such as crystallinity, transparency, and purity. Thus, accurate measurement is important. This study describes a new method to determine the wavelength dependent complex refractive index of cellulose nanocrystals (CNCs) by the measurement of light transmittance with a spectrophotometer. The data analysis is based on a combination of the Beer-Lambert and immersion liquid matching equations. The immersion liquid method's main advantage is that it is independent of particle shape and size. Moreover, the measurement is easy and relatively quick to perform. The present procedure is not restricted to the nanocellulose and could potentially be applied to other nanomaterials, such as hyphenate nanoparticle-based, lignin nanoparticles, nanopigments, biological entities, structural elements of dielectric metamaterials, and nanoparticle-based composites.
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| 4. |
- Rylander, David, 1981-
(författare)
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Productivity Improvements in Construction Transport Operation through Lean Thinking and Systems of Systems
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of a quarry is to extract rock material to deliver gravel and raw material to its customers. The products can be further processed to e.g., extract minerals such as iron or to produce cement and asphalt. These products are an important input to the construction and maintenance of road infrastructure, buildings, and more. The operation of quarry and road work sites is similar to the manufacturing industry since it contains sequential processes to produce the output product. Within the operation, there are cyclic transport activities that in general are not synchronized and controlled in real-time towards the overall throughput. This fact indicates a potential to increase productivity but also points at unsolved challenges.This thesis investigates how Lean and systems thinking combined with real-time control and optimization technologies can be used to improve productivity and safety in the transport operation within quarry and road construction. The main contributions are the identified operational improvements, its use cases, the system design constraints, operational characteristics, and models as well as assessed impact in productivity, energy efficiency, and safety.The results include the development and demonstration of a method based on Lean value stream mapping, for identifying wastes in sequential processes and activities including mobile earthmoving machines. Operational wastes of 33% are presented from real world operations. Related fuel savings of 42% are measured in controlled environments. Further, the thesis presents and assesses a system design for transport optimization purpose. A study of how wireless communication and vehicular ad-hoc networks (VANET) can be utilized and its performance within the quarry and road construction operation is presented. The main system requirements and constraints are identified, and the trade-offs are discussed in terms of system design with a system of systems perspective. Energy consumption models are developed for optimization purposes and the key characteristics of real world operation is identified. Finally, a prototype system has been developed and tested in controlled and operative environments. In controlled trials, a fuel reduction of 20% for individual machines was obtained using the suggested optimization technique.
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