| 1. |
- Alam, Anzar, et al.
(författare)
-
Online surface characterization of paper and paperboards in a wide-range of the spatial wavelength spectrum
- 2012
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 258:20, s. 7928-7935
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Tidskriftsartikel (refereegranskat)abstract
- In the paper industry, surface topography is the essence of both paper and paperboard, and accurate topographical measurements are equally essential in order to achieve a uniform smooth surface. The traditional laboratory methods measure only a few samples from the entire tambour and there are other obvious limitations to this approach. Online measurements may be of significant value to improve the surface quality throughout the production. Roughness is one of the topography components and the majority of techniques measure paper by means of a single predictor of average roughness, R a which is inadequate in providing a comprehensive characterization of the surface. Measurements, in a wide range ofwavelengths, can characterize topography components such as roughness, waviness, cockling, etc. Online measurements were taken for various grades of 8 paper reels, containing the wireside and topsides for newspaper, and uncoated and coated sides of paperboards. Their surfacecharacterization, in the spatial wavelength spectrum, from 0.1 to 10 mm was obtained. This article presents the online characterizationresults which have efficiently distinguished the surfaces of same family materials including the edge and the middle position reels of fine coatedpaperboard. Online measurements were taken, at Iggesund Paperboard Pilot Coater in Sweden, by using a recently developed OnlineTopography (OnTop) device which is based on the principle of light triangulation. © 2012 Elsevier B.V. All rights reserved.
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| 2. |
- Alam, Anzar, et al.
(författare)
-
Online surface roughness characterization of paper and paperboard using a line of light triangulation technique
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:3, s. 662-670
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Tidskriftsartikel (refereegranskat)abstract
- Within both the paper and paperboard industries, real time monitoring and measurement of surface roughness of a paper moving at high velocities is an important and challenging area of research. The uniform surface, for an entire production, can be effectively achieved by monitoring and controlling the paper surface roughness, in real time during the manufacturing steps. Presently the majority of paper industries rely on traditional laboratory profilometers. The obvious limitations of lab profilometers are that these are slow, do not measure the quality of entire reels but rather deal with only a few small pieces of samples taken from the end of the reels and it is difficult to make any possible correction in the productionlines without knowing the online roughness data. To eradicate the disadvantages associated with conventional measurements, an online prototype instrument has been developed that measures the surface roughness during the manufacturing steps, and is based on a line of lighttriangulation technique. The prototype technique will be of assistance in ensuring tight process control in order to maintain both a better and auniform quality throughout the entire production. It measures the whole reel, meter by meter, in traditional units of roughness and is also capable of characterizing the topography in a wide range of wavelength spectra. The article presents the online analyses results obtained from the developed prototype. The real time measurements, in a paperboard pilot mill, have successfully characterized and distinguished 16 different grades of newspaper and paperboard reels including reels which have the same family of quality grades and materials.
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| 3. |
- Alam, Mohammad Anzar, et al.
(författare)
-
Investigation of the surface topographical differences between the Cross Direction and the Machine Direction for newspaper and paperboard
- 2011
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 26:4, s. 468-475
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Tidskriftsartikel (refereegranskat)abstract
- Paper and paperboard surface quality is constantly being improved by the industry. This improvement work deals with the essential fact that the surface topography must be measured, both in relation to offline and online measurements for the manufactured products. Most measurements relating to surface topography (especially online) are performed either in the machine direction (MD) or in the cross direction (CD). It has been the opinion of SCA Ortviken AB and Iggesund Paperboard AB that the surface topography amplitudes are almost always higher in the CD than in the MD, for their products which consist of newspaper and paperboard. This article aims to investigate the rela-tionship between the CD and the MD surface topography amplitudes for a wide range of spatial wavelength for both newspaper and paperboard. The tests and investiga-tions have been conducted using an FRT Microprof profilometer within the range 20 μm up to 8 mm, and the results confirm that the surface topography amplitudes are higher in the CD for most of the shorter spatial wavelength within this range. The results also show significant differences between measurements for different paper qualities, suggesting a requirement to investigate the relationship between the CD and the MD topography for all paper and paperboard qualities of interest for a paper or paperboard mill, before a decision is made in relation to a measurement method.
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| 4. |
- Alam, Mohammad Anzar, et al.
(författare)
-
Limitation of a line-of-light online paper surface measurement system
- 2014
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:8, s. 2715-2724
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Tidskriftsartikel (refereegranskat)abstract
- A new prototype device has been developed based on a laser triangulation principle to measure online surface topography in the paper and paperboard industries. It characterizes the surface in a wide spatial scale of topography from 0.09-10 mm. The prototype's technique projects a narrow line-of-light perpendicularly onto the moving paper-Web surface and scattered reflected light is collected at a low angle, low specular, and reduced coherent length onto the CCD sensors synchronized with the laser sources. The scattering phenomenon determines surface deviations in the z-direction. The full-width, at half-maximum of a laser line in cross section is sensitive in computation of the surface topography. The signal processing aspect of the image processing, for example, threshold and filtering algorithms are also sensitive in estimating the accurate surface features. Moreover, improper light illumination, intensity, reflection, occlusion, surface motion, and noise in the imaging sensor, and so forth, all contribute to deteriorate the measurements. Optical techniques measure the surface indirectly and, in general, an evaluation of the performance and the limitations of the technique are both essential and challenging. The paper describes the accuracy, uncertainty, and limitations of the developed technique in the raw profiles and in terms of the rms roughness. The achieved image subpixel resolution is 0.01 times a pixel. Statistically estimated uncertainty (2σ) in the laboratory environment was found 0.05 μm for a smooth sample, which provides a 95% confidence level in the rms roughness results. The depth of field of the prototype is ~2.4 mm.
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| 5. |
- Alam, Mohammad Anzar
(författare)
-
Online optical method for real-time surface measurement using line-of-light triangulation
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Real time paper surface-web measurement is one of the challenging research fields. The traditional laboratory method has many limitations and is unable to measure the entire tambour during the manufacturing process. It has been necessary to develop an online technique that could measure the surface topography in real time. An optical technique was developed, based on laser triangulation, and is applied to develop a new prototype device, which characterizes high speed paper-web surfaces over a wide scale of spatial wavelengths spectrum and computes the surface roughness in real time. The used multi channel pulsed laser diode, source of illumination onto the paper-web, is of benefit due to its low coherence length and is capable to deliver a powerful burst of light beam over a 1 µs duration, which delivers energy of 100 µJ per pulse. The short exposure time avoids blurriness in the acquired images which could possible due to the high speed and vibrations on the paper-web.The laser beam is shaped into a narrow line-of-light using cylindrical lenses and is projected onto a paper-web surface, which covers a physical length of about 210 mm. The created line-of-light cross section full width at half maximum, FWHM Gaussian distribution, is 2-3 pixels on the image. The line-of-light is projected onto the paper-web perpendicular to the plane of the surface. The low angled, low specular, reduced coherence length, scattered reflected laser line is captured by the 3 CCD sensors, which are synchronized with the laser source. The low specular light ensures to avoid saturation of the imaging sensors if the surface is very smooth, and obliquely captures the z-directional fine feature of the surface.The scattered phenomenon of the reflected light is responsible for the surface irregularity measurements. The basic image processing algorithm is applied in order to remove noise and cropped the images widthwise so that only pixels above a preset threshold gray level can be processed, which enables efficient real time measurement. The image is transformed into a 1D array using the center of gravity, COG. The accuracy and precision of the COG depends on the line-of-light FWHM, which, in turn, is responsible for the accuracy, noise and the resolution of the developed technique. The image subpixel resolution achieved is 0.01 times a pixel and uuncertainty in the raw data is 0.43 µm while it is 0.05 µm in the rms roughness.The signal processing steps combining the B-Spline filter and the filter in the spatial frequency domain were employed in order to separate roughness, waviness, and form and position error in the raw profile. The prototype is designed to measure online surface roughness and to characterize surface in a spatial wavelength spectrum from 0.09 to 30 mm, which is extendable to any required spatial range in order to cover a wide scale surface feature such as micro roughness, macro roughness and waviness. It is proven that exploitation of a simple laser triangulation technique could lead to an improvement in the overall quality and efficiency in the paper and paperboard industries and it can also be of potential interest for the other surface characterization problems.
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| 6. |
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| 7. |
- Alam, Mohammad Anzar, et al.
(författare)
-
Real time surface measurement technique in a wide range of wavelengths spectrum
- 2014
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:1, s. 285-294
-
Tidskriftsartikel (refereegranskat)abstract
- Real time surface topography measurement in the paper and paperboard industries is a challenging research field. The existing online techniques measure only a small area of paper surface and estimate topographical irregularities in a narrow scale as a single predictor. Considering the limitations and complications in measuring the surface at high speed, a laser line triangulation technique is explored to measure surface topography in a wide scale. The developed technique is new for the paper and paperboard application that scans a line onto the paper-web surface up to 210 mm in length in the cross machine direction. The combination of a narrow laser linewidth imaging, a subpixel resolution, and the selection of a unique measurement location has made it possible to measure roughness and simultaneously characterize paper surface topography from 0.1 to 30 mm spatial wavelength. This spatial range covers wide scale surface properties such as roughness, cockling, and waviness. The technique clearly distinguishes and characterizes the surface of newspaper, and lightweight coated, coated, and uncoated paperboard in real time during the paper manufacturing process. The system temporal noise for the average roughness is estimated as 37 dB. The signal to noise ratio found is from 5.4 to 8.1 in the short spatial wavelength up to 1 mm, whereas it is more than 75 in the long spatial wavelength from 5 to 10 mm.
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| 8. |
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| 9. |
- Andersson, Henrik, et al.
(författare)
-
Assembling surface mounted components on ink-jet printed double sided paper circuit board
- 2014
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 25:9
-
Tidskriftsartikel (refereegranskat)abstract
- Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed.
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| 10. |
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| 11. |
- Andersson, Henrik, et al.
(författare)
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Chemically programmed ink-jet printed resistive WORM memory array and readout circuit
- 2014
-
Ingår i: Materials Research Express. - : Institute of Physics (IOP). - 2053-1591. ; 1:3, s. 035021-
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Tidskriftsartikel (refereegranskat)abstract
- In this paper an ink-jet printed write once read many (WORM) resistive memory fabricated on paper substrate is presented. The memory elements are programmed for different resistance states by printing triethylene glycol monoethyl ether on the substrate before the actual memory element is printed using silver nano particle ink. The resistance is thus able to be set to a broad range of values without changing the geometry of the elements. A memory card consisting of 16 elements is manufactured for which the elements are each programmed to one of four defined logic levels, providing a total of 4294 967 296 unique possible combinations. Using a readout circuit, originally developed for resistive sensors to avoid crosstalk between elements, a memory card reader is manufactured that is able to read the values of the memory card and transfer the data to a PC. Such printed memory cards can be used in various applications.
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| 12. |
- Andersson, Henrik, et al.
(författare)
-
Contacting paper-based supercapacitors to printed electronics on paper substrates
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 476-480
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid printed electronics, in which printed structures and silicon-based components co-exist will likely be among the first commercial solutions. In this case the paper substrate acts much in the same way as circuit boards, containing conductive tracks and acting as a carrier for the electrical components. It is important to consider the contacting of the components to be able to produce low resistance electrical contacts to the conductive tracks. Supercapacitors are able to deliver a large amount of current in a short time and are a good option for short term energy storage and if the printed product is to be used only one, or a few times, it can be the only power source needed. When manufacturing printed electronics, the overall resistance of the printed tracks as well as the contact resistance of the mounted components will add up to the total resistance of the system. A high resistance will cause a voltage drop from the power source to the component. This will waste power that goes to Joule heating and also the voltage and current available to components may be too low to drive them. If the intention is to use a power supply such as batteries or solar cells this becomes a limitation. In this article have been tested several conductive adhesives used to contact paper based supercapacitors to ink jet printed silver tracks on paper. The best adhesive gives about 0.3 Ω per contact, a factor 17 better compared to the worst which gave 5 Ω. The peak power that is possible to take out from a printed system with a flexible battery and super capacitors is about 10 times higher than compared with the same system with only the battery.
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| 13. |
- Andersson, Henrik, et al.
(författare)
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Evaluation of an Integrated Fourier-Transform Spectrometer Utilizing a Lateral Effect Position Sensitive Detector with a Multi-Channel Fabry-Perot Interferometer
- 2008
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Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 19:4, s. 045306-
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Tidskriftsartikel (refereegranskat)abstract
- The basis of this paper is the evaluation of an integrated multi-channel Fourier-transform (FT) spectrometer based on a multi-channel wedge Fabry-Perot interferometer and a one-dimensional lateral effect position sensitive detector (PSD). The use of a PSD for an interferogram readout allows for a simple scanning mechanism with no requirement for any position reference. The use of a wedge-shaped interferometer makes it possible to integrate it directly onto the PSD surface, thus producing a very compact spectrometer. The capabilities of the spectrometer are demonstrated by absorption spectral measurements using a reference sample. In addition, spectral measurements on 532 nm DPSS and 632.8 nm He-Ne lasers are presented. The resolution of the spectrometer is approximately 5 nm. The evaluated spectrometer set-up can be used in applications where compact and low cost spectrometers are required, such as in process control and in education. Further, it is shown that there are deteriorations in very high accuracy position measurements, which are caused by changes in incident light intensity. A model describing the above-mentioned nonlinearities was developed based on analysing the equivalent circuit for PSDs and parameters such as leakage current and serial resistance. Additionally, a method is proposed to assist in the reduction of the nonlinearity caused by this effect.
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| 14. |
- Andersson, Henrik, et al.
(författare)
-
Evaluation of coatings applied to flexible substrates to enhance quality of ink jet printed silver nano-particle structures
- 2012
-
Ingår i: IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part C. - 1083-4400 .- 1558-1241. ; 2:2, s. 342-348
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Tidskriftsartikel (refereegranskat)abstract
- Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrate. Originally these coatings have been specified to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not otherwise possible with this type of ink on this substrate types. It has been found that the coating Semi Gloss provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5*10-7Ωm at best when sintered at 150°C and for polyimide 8.9*10-8Ωm sintered at 200°C. This corresponds to a conductivity of about 4.5% and 18%of bulk silver, respectively. It can be concluded that applying such PVP based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.
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| 15. |
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| 16. |
- Andersson, Henrik, et al.
(författare)
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Inkjet printed silver nanoparticle humidity sensor with memory effect on paper
- 2012
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:6, s. 1901-1905
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the design and the manufacture of an inkjet printed resistive type humidity sensor on paper are reported. After having been exposed to humidity above a given threshold level, the resistance of the sensor decreases substantially and remains at that level even when thehumidity is reduced. It is possible to deduce the humidity level by monitoring the resistance. The main benefit of the printed sensor presented in this case is in relation to its very low production costs. It has also been shown that both the ink type and this paper combination used prove to be crucial in order to obtain the desired sensor effect. More research is required in order to fully understand the humidity sintering effect on the nano particle ink and the role of the substrate. However, the observed effect can be put to use in printed humidity sensors which possess a memoryfunction. The sensor can be used in various applications for environmental monitoring, for example, in situations where a large number of inexpensive and disposable humidity sensors are required which are able to detect whether they have been subjected to high humidity. This could be the checking of transportation conditions of goods or monitoring humidity within buildings. © 2001-2012 IEEE.
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| 17. |
- Andersson, Henrik, et al.
(författare)
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Investigation of Humidity Sensor Effect in Silver Nanoparticle Ink Sensors Printed on Paper
- 2014
-
Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:3, s. Art. no. 6615915-
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Tidskriftsartikel (refereegranskat)abstract
- Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink.
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| 18. |
- Andersson, Henrik, et al.
(författare)
-
Modified EAS Tag Used as a Resistive Sensor Platform
- 2012
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Ingår i: Electronics. - : MDPI AG. - 2079-9292. ; 1:2, s. 32-46
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Tidskriftsartikel (refereegranskat)abstract
- In this article, a modified design of an RF Radio Frequency Electronic ArticleSurveillance (EAS) tag, used as a sensor platform, is manufactured and characterized. EAStags are passive devices consisting of a capacitor and coil, tuned to a resonance frequencyreadable by the detector equipment, in this case 8.2 MHz. They were originally used todetect whether merchandise was being moved through the detection gates at shop exits, inwhich case an alarm was triggered. If the capacitance is divided in two and a resistivesensor device inserted in between, the resonant Inductor-Capacitor (LC) circuit becomes anInductor-Capacitor-Capacitor-Resistor LCCR circuit and can be used as a sensor tag. Ahigh sensor resistance means that one capacitor is decoupled, leading to one resonancefrequency, while a low resistance will couple both capacitances into the circuit, resulting ina lower resonance frequency. Different types of resistive sensors exist that are able todetect properties such as pressure, moisture, light and temperature. The tag is manufacturedin Aluminum foil on a polyetylentereftalat (PET) substrate, resulting in a cost effectiveRF-platform for various resistive sensors. Two types of tags are designed andmanufactured, one with parallel plate capacitors and the other with interdigital capacitors.To test the tags, a resistive tilt sensor is mounted and the tags are characterized using anetwork analyzer. It is shown that for high resistance, the tags have a resonance frequencyof more than 10 MHz while for low values the frequency approaches 8.2 MHz.
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| 19. |
- Andersson, Henrik, et al.
(författare)
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Principle of FT Spectrometer based on a Lateral Effect Position Sensitive Detector and Multi Channel Fabry-Perot Interferometer
- 2009
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Ingår i: Measurement. - : Elsevier BV. - 0263-2241 .- 1873-412X. ; 42:5, s. 668-671
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Tidskriftsartikel (refereegranskat)abstract
- The principle of a new type of multi channel Fourier-Transform spectrometer based on a multi channel wedge Fabry-Perot interferometer using a one dimensional lateral effect Position Sensitive Detector and a scanning slit for interferogram readout have been shown. The design of this spectrometer is very compact and the readout electronics very simple. The drawback of using a scanning slit system is minimized by the use of a position sensitive detector where the position is inherently known for each measurement. Experiments show that the position can be resolved with high accuracy and the summation of the two photocurrents gives the interferogram after scanning the slit between the wedge interferometer and the position sensitive detector. The spectral resolution obtained with a 25mm wedge interferometer together with a 45mm position sensitive detector and a 25µm slit is about 5nm around 600nm wavelength range, which is close to the theoretically anticipated resolution. The evaluated spectrometer setup show promising results and could be used in applications where compact and low cost spectrometers are required.
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| 20. |
- Andersson, Henrik, et al.
(författare)
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System of nano-silver inkjet printed memory cards and PC card reader and programmer
- 2011
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Ingår i: Microelectronics Journal. - : Elsevier BV. - 0959-8324 .- 0026-2692. ; 42:1, s. 21-27
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Tidskriftsartikel (refereegranskat)abstract
- This work describes the development of inkjet printed, low-cost memory cards, and complementary pair of memory card reader and card reader/programmer for PCs. This constitutes a complete system that can be used for various applications. The memory cards are manufactured by inkjet printing nano-silver ink on photo paper substrate. The printed memory structures have an initial high resistance that can later be programmed to specific values representing data on the cards, the so called Write Once Read Many (WORM) memories. The memory card reader measures the resistance values of the memory cells and reads it back to the computer by USB connection. Using multiple resistance levels that represent different states it is possible to have a larger number of selectable combinations with fewer physical bits compared to binary coding. This somewhat counters one of the limitations of resistive memory technology that basically each cell needs one physical contact. The number of possible states is related to the resolution of the reader and the stability of the WORM memory.
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| 21. |
- Andersson, Henrik, et al.
(författare)
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The influence of paper coating content on room temperature sintering of silver nanoparticle ink
- 2013
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 24:45, s. Art. no. 455203-
-
Tidskriftsartikel (refereegranskat)abstract
- The resistance of inkjet printed lines using a silver nanoparticle based ink can be very dependent on the substrate. A very large difference in resistivity was observed for tracks printed on paper substrates with aluminum oxide based coatings compared to silica based coatings. Silica based coatings are often cationized with polymers using chloride as a counter ion. It is suggested that the precipitation of silver salts is the cause of the high resistivity, since papers pretreated with salt solutions containing ions that precipitate silver salts gave a high resistance. Silver nitrate has a high solubility and paper pretreated with nitrate ions gave a low resistivity without sintering. The results obtained show that, by choosing the correct type of paper substrate, it is possible to manufacture printed structures, such as interconnects on paper, without the need for, or at least to reduce the need for, post-print sintering. This phenomenon is, of course, ink specific. Inks without or with a low silver ion content are not expected to behave in this manner. In some sensor applications, a high resistivity is desired and, by using the correct combination of ink and paper, these types of sensors can be facilitated.
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| 22. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Blood pH optrode based on evanescent waves and refractive index change
- 2014
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 9780819498519 ; , s. Art. no. 89381F-
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Konferensbidrag (refereegranskat)abstract
- Sensing pH in blood with an silica multimode optical fiber. This sensor is based on evanescent wave absorption and measures the change of the refractive index and absorption in a cladding made of a biocompatible Polymer. In contrast to many existing fiber optical sensors which are based upon different dyes or florescent material to sense the pH, here presents a solution where a part of the cladding is replaced with a Poly (β-amino ester) made of 1.4-Butanediol diacrylate, Piperazine, and Trimethylolpropane Triacrylate. Piperazine has the feature of changing its volume by swelling or shrinking in response to the pH level. This paper utilizes this dimension effect and measure the refractive index and the absorption of the cladding in respect to different pH-levels. The alteration of refractive index also causes a change in the absorption and therefore the output power changes as a function of the pH level. The sensor is sensitive to pH in a wide spectral range and light absorbency can be observed for wavelengths ranging from UV to far IR. © 2014 SPIE.
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| 23. |
- Hammarling, Krister, 1968-, et al.
(författare)
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FBG based upon evaporated Silica nano particles
- 2011
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Ingår i: 1st EOS Topical Meetingon On Micro- and Nano-Optoelectronic Systems, Bremen, December 7-9, 2011.
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Konferensbidrag (refereegranskat)abstract
- A fiber bragg grating was made by evaporating silica nano particles on the outside of a multimode silica fiber core using EISA method. We demonstrate that a cost effective bragg filter may be built by evaporating nano particles directly on a fiber core, which is tunable with the particle size.
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| 24. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Fiber Bragg Grating filter using Evaporated Induced Self Assembly of silica nano particles
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. ; , s. Art. no. 898225-
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Konferensbidrag (refereegranskat)abstract
- In the present work we conduct a study of ber lters produced by evaporation of silica particles upon aMM-ber core. A band lter was designed and theoretically veried using a 2D Comsol simulation model ofa 3D problem, and calculated in the frequency domain in respect to refractive index. The ber lters werefabricated by stripping and chemically etching the middle part of an MM-ber until the core was exposed. Amono layer of silica nano particles were evaporated on the core using an Evaporation Induced Self-Assembly(EISA) method. The experimental results indicated a broader bandwidth than indicated by the simulationswhich can be explained by the mismatch in the particle size distributions, uneven particle packing and nallyby eects from multiple mode angles. Thus, there are several closely connected Bragg wavelengths that buildup the broader bandwidth. The experimental part shows that it is possible by narrowing the particle sizedistributing and better control of the particle packing, the lter eectiveness can be greatly improved.
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| 25. |
- Manuilskiy, Anatoliy, et al.
(författare)
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Compact Multi Channel Optical Fourier Spectrometer
- 2006
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9780819464934 ; , s. U34-U43
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Konferensbidrag (refereegranskat)abstract
- In this work are shown the principle, first experimental results and a model design of a new type of multi channel Fourier transform (FT) spectrometer for visible (VIS) and infrared (IR) region operating in real time. The main principle of this spectrometer is that measured collected and collimated optical radiation passes through a linear array or matrix of optical Fabry-Perot interferometers. Each interferometer is placed in front of and close to each element of the array detector. By processing the signal the spectrum of the optical radiation can be extracted. This design does not require intermediate optics between interferometer and array detector and allows for a reliable and extremely compact construction. Production cost can be low when a simple wedge type interferometer is integrated with existing array or matrix detectors, e.g. CCD camera. One other benefit is that the shape of the interferometer determines whether the spectrometer is suitable for measuring wide spectra radiation or has the ability to discriminate optical coherent radiation. Experimental results achieved for VIS and NIR range of spectra are promising. The principals of this design can be used for a variety of applications besides as a spectrometer. For example warning systems for lasers and restricted coherency sources and also filtering of optical signals and for measuring the spectral content working in a wide spectral range.
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| 26. |
- Manuilskiy, Anatoliy, et al.
(författare)
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Multi Channel Array Interferometer-Fourier Spectrometer
- 2006
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Ingår i: 2006 Northern Optics Conference Proceedings. - New York : IEEE. - 9781424404353 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- The characterization and design of a Fourier transform spectrometer, which enables the integration of a multi channel interferometer with a detector unit in order to create a compact device is presented in this paper. It operates within a wide spectral range from visible to NIR, contains no moving parts and is resistible to mechanical and climatic conditions. Such a design with an array or matrix detector can be used for spectroscopy with a partially coherent or white optical source depending on the shape of the optical interferometer. A reasonable spectral resolution of the order of 20-50 cm-1 can be achieved over a 1 µm wavelength range when using a 512 pixel detector array. A design model for characterization of the quasi integrated device, where a multi channel interferometer was mechanically attached and which contained a gap to the detector elements, was used. The experimental results are promising and suggest a variety of different directions for the development and application of these types of integrated spectrometers.
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| 27. |
- Nilsson, Hans-Erik, et al.
(författare)
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Printed write once and read many sensor memories in smart packaging applications
- 2011
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 11:9, s. 1759-1767
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Tidskriftsartikel (refereegranskat)abstract
- A horizontal printed Write Once Read Many (WORM) resistive memory has been developed for use in wireless sensortags targeting single event detection in smart packaging applications. The WORM memory can be programmed using a 1.5 V printedbattery. An alternative programming method is to use chemical sintering which allows the development of exposure-time triggeredsingle event tags that can be accessed wirelessly. The new WORM memory has very low losses in the ON-state which allows directintegration into antenna structures.A sensor tag that utilizes the WORM memory functionality and the well established Electronic Article Surveillance (EAS)communication standard has been outlined. Both active and fully passive sensor tag solutions have been proposed.The role of printed electronics in smart packaging applications has been reviewed and discussed. Important enabling factors forthe future development have been highlighted, such as the need for hierarchical design and test tools, better printed interconnecttechnologies as well as better components that allow communication with existing information and communication technology (ICT)standards. This is illustrated and underlined by the presented smart packaging concept demonstrators.
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| 28. |
- Nilsson, Hans-Erik, et al.
(författare)
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System integration of electronic functions in smart packaging applications
- 2012
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Ingår i: IEEE Transactions on Components, Packaging and Manufacturing Technology. - 2156-3950. ; 2:10, s. 1723-1734
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Tidskriftsartikel (refereegranskat)abstract
- A system integration scheme relevant for smart packaging applications is presented. Recent advances in printed electronics, radio frequency identification tag production, and standardization of communication protocols are factors that increase the design freedom for new applications. As in all new technology fields, the first products are expected to appear in the high-cost segment attracting early adopters in the form of niche products. A reasonable assumption is that these products will come from hybridization of different types of technologies. Such a scenario is likely since no technology solution available can provide all features that these types of applications demand. There is a need of standard solutions for hybridization of silicon devices and printed (or foil-type) components. Conductive ink technology is a powerful tool for hybridization and customization of large-area electronics, providing 3-D integration and large-area customization. However, high-performance communication and advanced processing demand the use of silicon. Smart hybridization solutions allow combination of the best from both worlds. This paper analyzes the requirements on hybridization technologies suitable for smart packaging applications and provides design examples on integration of intrusion surveillance solutions for cellulose-based packaging applications. It shows that even though the current hybridization technologies are far from optimal, they can provide a considerable design freedom and system performance. © 2011-2012 IEEE.
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| 29. |
- Norlin, Börje, et al.
(författare)
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Material recognition with the Medipix photon counting colour X-ray system.
- 2004
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 531:1-2, s. 265-269
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Tidskriftsartikel (refereegranskat)abstract
- An energy sensitive imaging system like Medipixl has proved to be promising in distinguishing different materials in an X-ray image of an object. We propose a general method utilising X-ray energy information for materialrecognition. For objects where the thickness of the materials is unknown, a convenient material parameter to identify is K = α1/α2, which is the ratio of the logarithms of the measured transmissions In(t1)/In(t2). If a database of the parameter K for different materials and energies is created, this method can be used for material recognition independent of the thickness of the materials. Series of images of an object consisting of aluminium and silicon were taken with different energy thresholds. The X-ray absorption for silicon and aluminium is very similar for the range 40-60 keV and only differs for lower energies. The results show that it is possible to distinguish between aluminium and silicon on images achieved by Medipixl using a standard dental source. By decreasing the spatial resolution a better contrast between the materials was achieved. The resolution of contrasts shown by the histograms was close to the limit of the system due to the statistical noise of the signal.
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| 30. |
- Thim, Jan, 1977-, et al.
(författare)
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Simulating the Impact of Topographical Microstructures on Triangulation Measurement Setups using Matlab
- 2008
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Ingår i: Proceedings of Nordic MATLAB User Conference.
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Konferensbidrag (refereegranskat)abstract
- The paper manufacturing industry is currently exploring the possibility of measuring micro structural topography online in a paper manufacturing machine, which is intended to lead to a more precise measure of the paper quality reel to reel and a more efficient use of raw material. This paper presents a Matlab simulation model that can be used to configure such measurement readout systems, and includes a demonstration of the model in use. The model will also be used for research purposes in order to assist in gaining a better understanding of both the limitations and possibilities of such measurement systems. In this regard the angular shading of microstructures and Centre of Gravity (CoG) functions are included in the attributes that require further exploration.
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