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This article investigates Baroque instruments of the violin family whose bodies have been reduced. The morphology of this family of instruments before 1750 remains surprisingly little known, as does their timbre and the sound balance between the different family members. Historical sources document two ways of reducing the body of a violin: in length, or in width. We have developed a technique for the large-scale analysis of these reductions, applicable on 3D models generated either by CT-scans or 3D models generated by photogrammetry. This investigation method has been applied to two instruments kept in the Brussels Musical Instruments Museum: an undated viola, heavily reduced, attributed to the Antwerp violin maker Matthijs Hofmans (1622–1672), and a viola dated 1761, for which visual examination does not reveal the slightest trace of reduction: a viola by Johannes Theodorus Cuypers (1719–1806), a violin maker active in The Hague.

This thesis aimed to validate Beekman's patent on how collimation could virtually reduce the focal spot size of an existing small-animal cone beam Computed Tomography (CT) system to diminish the penumbra effect. The ever-remaining drive to improve the spatial resolution in CT for enhanced image quality introduces the need for small focal spot sizes, as the focal spot size is directly related to the geometric unsharpness in the image. Therefore, a collimation method was proposed to virtually reduce the focal spot of existing systems as an alternative to fully replace the current X-ray tube. A collimator was designed, consisting of numerous tiny hexagonal-shaped holes focused at the center of the focal spot. Theoretical derivations were formulated for its dimensions, and the collimator's efficacy was validated using Monte Carlo simulations. It was concluded that it is theoretically achievable to use collimation to virtually reduce the focal spot size to an arbitrarily chosen smaller virtual focal spot for existing CT systems, significantly reducing the penumbra effect, without requiring any integral changes to the X-ray tube. However, the collimator's practical suitability and manufacturing feasibility were problematic due to its significantly low collimator sensitivity and exceptionally tiny dimensions. Future work could build on this thesis by obtaining reconstructions from multiple projections of the virtual focal spot to quantitatively assess their theoretically improved spatial resolution. The quantitative confirmation could further establish the theoretical effectiveness of focal spot collimation for future work to enhance reconstructions to uncover valuable information previously hidden., Biomedical Engineering

The rail transportation system has been a cornerstone of the modern economy due to its low cost and environmental sustainability. However, the rapid expansion of railway mileage and the aging of existing infrastructure have posed challenges for efficient and widespread rail inspection systems. Existing approaches are hindered by their high costs and the occupation of tracks. In this study, we present a high-efficiency RF energy harvesting system using a mini-branch line coupler (Mini-BLC) for railway monitoring. The Mini-BLC effectively reduces the return loss caused by impedance mismatch and optimizes the high-efficiency region for high-power input. Using T-shape equivalent circuits, the size of mini-BLC is reduced by 30%. The wirelesspowered sensor tag (WPST) exhibits an overall efficiency of 26.3% at the input power of 8 dBm, which is 33% higher than the efficiency of the conventional scheme at the same input power. The presented strategy is generalizable for developing multi-functional RF energy-powered systems with other frequency bands and power regions.

Milling is a critical step to prepare plant-based food ingredients by dry fractionation. It should provide a dispersible flour of finely milled particles composed of different cellular substructures. Especially, for raw materials with higher oil content such as soybean, this is challenging. We present an investigation on the effect of oil content on milling yield, particle size, energy use and flour dispersibility upon pin-milling of soybean. Soybean (20 g oil/100 g dry solids) and mechanically de-oiled soybeans (9–17 g oil/100 g dry solids) were subjected to pin-milling experiments. Increasing soybean oil content limited milling to smaller particles and lowered the overall milling yield. Particle size reduction can be described with an adapted Bond's model with oil content as an input parameter. The produced soy flours were well dispersible.

Particle size of diets or ingredients plays an important role in pig growth and gut health. The way the size of particles is measured and expressed, however, is limited in explaining pig growth performance differences. This review explores new possibilities to determine, express and predict particle size. Different grinding methods, including the use of roller mills, hammer mills, multicracker and multi-stage grinding were reviewed. Roller milling tends to produce a more uniform particle size distribution (PSD) and consumes less energy, whilst hammer mills have a greater grinding capacity and a higher reduction ratio compared to roller mill. The multicracker system, a more recently developed technology, can be considered cost-effective and ensures grinding capacity. Since the effects of different grinding methods vary, multi-stage grinding, combining different grinding methods, might be a solution to obtain a defined PSD. Particle size determination techniques, including dry/wet sieving, laser diffraction, microscopy, and static/dynamic image analysis are described and compared. It is concluded that more characteristics of particles (e.g. shape, volume or surface area) should be investigated. Besides geometric mean diameter (GMD), particle size can also be expressed with parameters such as D50, D4,3 and span of PSD. Equivalent particle size (EPS) is introduced as a mean of describing the size of particles related to a functional trait of the particles. A meta-analysis was performed by collecting particle size and pig performance data from scientific studies examining the effect of recalculated EPS on pig performance (feed conversion ratio, FCR). Regression/linear modelling shows that recalculated EPS was not better than GMD in explaining pig performance differences due to the high variation among studies. Different expressions of PSD may result in different conclusions. An introduction of describing the breaking behavior of diet ingredients via mathematical models i

BACKGROUND: Pretreatment is effective in reducing the natural recalcitrance of plant biomass so polysaccharides in cell walls can be accessed for conversion to sugars. Furthermore, lignocellulosic biomass must typically be reduced in size to increase the pretreatment effectiveness and realize high sugar yields. However, biomass size reduction is a very energy-intensive operation and contributes significantly to the overall capital cost. RESULTS: In this study, the effect of particle size reduction and biomass presoaking on the deconstruction of Alamo switchgrass was examined prior to pretreatment by dilute sulfuric acid (DSA) and Co-solvent Enhanced Lignocellulosic Fractionation (CELF) at pretreatment conditions optimized for maximum sugar release by each pretreatment coupled with subsequent enzymatic hydrolysis. Sugar yields by enzymatic hydrolysis were measured over a range of enzyme loadings. In general, DSA successfully solubilized hemicellulose, while CELF removed nearly 80% of Klason lignin from switchgrass in addition to the majority of hemicellulose. Presoaking and particle size reduction did not have a significant impact on biomass compositions after pretreatment for both DSA and CELF. However, presoaking for 4 h slightly increased sugar yields by enzymatic hydrolysis of DSA-pretreated switchgrass compared to unsoaked samples, whereas sugar yields from enzymatic hydrolysis of CELF solids continued to increase substantially for up to 18 h of presoaking time. Of particular importance, DSA required particle size reduction by knife milling to < 2 mm in order to achieve adequate sugar yields by subsequent enzymatic hydrolysis. CELF solids, on the other hand, realized nearly identical sugar yields from unmilled and milled switchgrass even at very low enzyme loadings. CONCLUSIONS: CELF was capable of achieving nearly theoretical sugar yields from enzymatic hydrolysis of pretreated switchgrass solids without size reduction, unlike DSA. These resul

Cheaper methods and raw materials are currently being sought for the production of microfibrillated cellulose. Presently microfibrils with high lignin content have attracted increasing interest. Wood residues, like sawdust, are good candidates due to their abundancy and low price but the recalcitrant nature of the lignocellulose complex is an obstacle for the mechanical separation of microfibrils directly from wood. The purpose of this study was to investigate whether the mild sulfonation pretreatment of pine sawdust with sodium sulfite in neutral and mild alkaline conditions could enhance mechanical fibrillation in ultrafine wet grinding. Sawdust sulfonated at pH 7 and 9 resulted in a lignin sulfonation degree of 0.5–0.6% with a yield loss of 5–6%, approximately half of which was due to the dissolution of extractives from the initial content of 4.7% to 1.3–1.5%. Sawdust (with and without sulfonation) was pre-ground first in a twin-screw extruder, followed by ultrafine grinding with a friction grinder at a temperature of 80 °C. The viscosity and size distribution of the microfibrillated sample suspensions were determined. Additionally, the samples were filtered on a membrane, dried, and the mechanical properties of the sheets made from the samples were measured. The results showed that the sulfonation of softwood sawdust is a promising economic and environment-friendly method to produce microfibrillated cellulose with high lignin content (above 28%), having excellent strength properties, low viscosity, and fast dewatering rates. The sheets made from the sulfonated samples yielded an almost twofold increase in tensile strength and Young’s modulus (100 MPa and 7–7.5 GPa, respectively) compared to the reference sample without sulfonation (52 MPa and 4.3 GPa) at an applied net grinding energy of 7 MW h per ton. It was found that the size of the fibrils was at a similar level with and without sulfonation, but the bonding ability of the sulfonated samples was cle

Med de växande hoten från klimatförändringar är det av största vikt att vi minskar vårt beroende av fossila bränslen och börjar använda oss utav mer förnyelsebara energikällor. En utav dessa förnyelsebara energikällor som för oss närmare ett cirkulärt resurshanteringssystem är produktionen av biogas från biologiskt avfall. Syftet med denna rapport är att bidra till expansionen av i huvudsak den småskaliga biogasproduktionen genom att identifiera kriterier som kopplar minskning av partikelstorlek med energibalansen över biogasproduktionssystemet. Genom att göra detta hoppas vi kunna hitta den optimala partikelstorleken för sönderdelning av substratet. För att uppnå detta gjordes en studie över biogasprocessen och de tillgängliga substraten samt sönderdelningsteknologierna. Denna studie visade att halm, gödsel och utsorterade grödor var några av de huvudsakliga intressanta substraten och att mekanisk sönderdelning är det som främst är lämpligt för småskalig biogasproduktion. Från detta kunde den optimala partikelstorleken identifieras genom att jämföra energin från det ökade biogasutbytet med energiförbrukningen av sönderdelaren, specifikt för substratet halm och sönderdelningsteknikerna hammarkvarn och knivkvarn. Detta resulterade i en optimal partikelstorlek för knivkvarn på 0,26mm och för hammarkvarn på 1,59 mm, dock visade känslighetsanalysen att förändringar i energibalansen kunde ändra hammarkvarnens optimum till en betydligt större partikelstorlek. Även om resultatet tydligt visar att knivkvarnen är överlägsen när det kommer till energieffektivitet finns det flera andra faktorer som påverkar vilken metod som blir mest effektiv för olika förhållanden och substrat, där de två främsta faktorerna är teknologins robusthet och substratets egenskaper som fuktighet och struktur. Det är av yttersta vikt att ökningar i effektivitet som den nämnd ovan görs för att ge biogas en möjlighet att slå sig in på bränsle och energimarknaden samt möjliggöra det till att bli ett vik, With the growing threats from climate change it is vital that we are able to lessen our reliance of fossil fuels and start using more renewable energy sources. One of these renewable energy sources which brings us closer to a circular resource management system is the production of biogas from biological waste. The purpose of this report is to help the expansion of mainly the small-scale biogas production technology through identifying criteria connecting size reduction to the energy balance of the biogas production system. By doing this we hope to find the optimal particle size reduction of the substrate. To achieve this, a study was done to map the biogas process and find out which substrates and size reduction technologies are currently available. The study concluded that wheat straw, manure and sorted out crops where some of the main substrates of interest and that mechanical size reduction is most suitable for small scale biogas plants. From this the optimal particle size could be found through comparing the energy from the increase in biogas yield with the energy costs of the size reduction equipment specifically for the substrate wheat straw and the mechanical size reduction technologies hammer mill and knife mill. This resulted in an optimal particle size through knife milling of 0.26 mm and by hammer milling 1.59 mm, although the sensitivity analysis showed that changes in the energy balance could shift the optimum of the hammer mill closer to a significantly larger particle size. Even though the results clearly show that knife mills are superior when it comes to energy efficiency there are several other factors that affect which method is most efficient for different substrates and conditions, with the two main being the robustness of the technology and the characteristics of the substrate such as moisture content and structure. Increases in efficiency like, the one mentioned above, is done to give biogas a fighting chance on the fuel and energy market and

Med de växande hoten från klimatförändringar är det av största vikt att vi minskar vårt beroende av fossila bränslen och börjar använda oss utav mer förnyelsebara energikällor. En utav dessa förnyelsebara energikällor som för oss närmare ett cirkulärt resurshanteringssystem är produktionen av biogas från biologiskt avfall. Syftet med denna rapport är att bidra till expansionen av i huvudsak den småskaliga biogasproduktionen genom att identifiera kriterier som kopplar minskning av partikelstorlek med energibalansen över biogasproduktionssystemet. Genom att göra detta hoppas vi kunna hitta den optimala partikelstorleken för sönderdelning av substratet. För att uppnå detta gjordes en studie över biogasprocessen och de tillgängliga substraten samt sönderdelningsteknologierna. Denna studie visade att halm, gödsel och utsorterade grödor var några av de huvudsakliga intressanta substraten och att mekanisk sönderdelning är det som främst är lämpligt för småskalig biogasproduktion. Från detta kunde den optimala partikelstorleken identifieras genom att jämföra energin från det ökade biogasutbytet med energiförbrukningen av sönderdelaren, specifikt för substratet halm och sönderdelningsteknikerna hammarkvarn och knivkvarn. Detta resulterade i en optimal partikelstorlek för knivkvarn på 0,26mm och för hammarkvarn på 1,59 mm, dock visade känslighetsanalysen att förändringar i energibalansen kunde ändra hammarkvarnens optimum till en betydligt större partikelstorlek. Även om resultatet tydligt visar att knivkvarnen är överlägsen när det kommer till energieffektivitet finns det flera andra faktorer som påverkar vilken metod som blir mest effektiv för olika förhållanden och substrat, där de två främsta faktorerna är teknologins robusthet och substratets egenskaper som fuktighet och struktur. Det är av yttersta vikt att ökningar i effektivitet som den nämnd ovan görs för att ge biogas en möjlighet att slå sig in på bränsle och energimarknaden samt möjliggöra det till att bli ett vik, With the growing threats from climate change it is vital that we are able to lessen our reliance of fossil fuels and start using more renewable energy sources. One of these renewable energy sources which brings us closer to a circular resource management system is the production of biogas from biological waste. The purpose of this report is to help the expansion of mainly the small-scale biogas production technology through identifying criteria connecting size reduction to the energy balance of the biogas production system. By doing this we hope to find the optimal particle size reduction of the substrate. To achieve this, a study was done to map the biogas process and find out which substrates and size reduction technologies are currently available. The study concluded that wheat straw, manure and sorted out crops where some of the main substrates of interest and that mechanical size reduction is most suitable for small scale biogas plants. From this the optimal particle size could be found through comparing the energy from the increase in biogas yield with the energy costs of the size reduction equipment specifically for the substrate wheat straw and the mechanical size reduction technologies hammer mill and knife mill. This resulted in an optimal particle size through knife milling of 0.26 mm and by hammer milling 1.59 mm, although the sensitivity analysis showed that changes in the energy balance could shift the optimum of the hammer mill closer to a significantly larger particle size. Even though the results clearly show that knife mills are superior when it comes to energy efficiency there are several other factors that affect which method is most efficient for different substrates and conditions, with the two main being the robustness of the technology and the characteristics of the substrate such as moisture content and structure. Increases in efficiency like, the one mentioned above, is done to give biogas a fighting chance on the fuel and energy market and

The role of rotor impact mill screen plate design in biomass grinding has attracted limited interest. This study aimed to clarify the effect of operational parameters and various screen designs on the fine grinding of Sphagnum moss. Contoured screens having forward (rasp) and backward (inverse rasp) inclined trapezoidal apertures of nominal sizes 0.2, 0.3, 0.4, and 0.5 mm were studied. A smooth screen plate having circular perforations (0.5 mm) was used as a reference. Flow phenomena were modeled with Computational Fluid Dynamics (CFD) using 2D geometry for the screen apertures. Product particle size and capacity were mostly dependent on the equivalent diameter of the screen apertures together with rotor frequency and also on the screen design, while the aspect ratio was solely a function of particle size. Among the screens having nominal sizes of 0.3, 0.4, and 0.5 mm, the smooth screen produced the smallest particle size; followed by the rasp screens and the inverse rasp screens. The smooth screen had higher capacity than the rasp or inverse rasp screens, and a narrower operating range. In the case of 0.2 mm apertures, higher capacity was achieved with the inverse rasp than with the rasp screen. The net energy consumption (SEC) of grinding with the rasp screens was at a lower level than with the inverse rasp screens (or the smooth screen). No difference was seen in the case of the smallest size apertures, however. The results, supported by CFD modeling, indicate that the incidence angle of particles does not explain the passage of particles through screen apertures. The passage is affected by the flow patterns above and within the apertures, and the pressure difference over the screen plate. The eddies within the apertures reduce their effective open area, resulting in product particles much smaller than the aperture size. When the aperture inclination is toward the tangential flow (rasp), an eddy is also generated in front of the aperture that turns the f

Due to its abundance, wood is the pre-eminent lignocellulosic raw material for a sustainable bioeconomy based society. Wood is widely used as fuel, construction material, and raw material in cellulose and lignocellulose based products. Besides the established uses of wood powder, like co-firing with coal and biofuel production, there are also novel uses and process applications, e.g., advanced wood-plastic composites and biochemical production are emerging for which the pulverization or fine grinding of wood is an essential pre-treatment step. Due to the tenacious nature of the wood matrix, size reduction is an energy intensive process and thermal or chemical pre-treatment may be needed to improve economy. This paper provides a broad overview of the fine grinding of wood. First, wood breakage mechanisms and the mechanisms of size reduction are presented, followed by fine grinding techniques and wood pre-treatment methods. A comparison of the specific energy consumption of wood fine grinding in both a gaseous and liquid environment is illustrated. Additionally, examples are given of the role played by pre-treatment methods in decreasing energy consumption. The particle aspect ratio is discussed briefly. Finally, the use and requirements of wood powders in various applications are discussed.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

The effect of parameters such as varying time duration of osmosis and sugar syrup concentration at the time of osmotic dehydration of raw guava slices(5 mm thick) and cubes on mass transfer data such as water loss,solid gain and mass reduction were studied. Sucrose solution of 700B and 800B was employed as per osmotic dehydration process. After completion of osmotic dehydration process, the water loss from guava cubes and guava slicesof 700B is found as 28.45 to 44.41 and 23.49 to 36.14 per sent resp. and of 800B is found as 30.90 to 49.6 and 30.5 to 47.61per cent resp. Similarly,sugar gain and mass reduction was calculated for guava slices and guava cubes. It was observed that the mass reduction, water loss and sugar gain increases with increase in sugar syrup concentration and duration of osmosis.

A large enhancement of the magnetic anisotropy of Ni nanowires (NWs) embedded in anodic aluminium oxide porous membranes is obtained as a result of an induced magnetoelastic (ME) anisotropy contribution. This unusual large anisotropy enhancement depends on the diameter of the NWs and exceeds the magnetostatic (MS) contribution. As a consequence, it leads to effective magnetic anisotropy energies as large as 1.4 ´ 106 erg cm−3, which are of the same order of magnitude and comparable to the MS energies of harder magnetic materials like Co NWs. Specifically, from ferromagnetic resonance experiments, the magnetic anisotropy of the NWs has been observed to increase as its diameter is decreased, leading to values that are about four times larger than the corresponding value when only the MS anisotropy is present. Our results are consistent with the recently proposed growth mechanism of Ni NWs that proceeds via a polycrystalline stage at the bottom followed by a single-crystalline stage with texture [110] parallel to the axis of the NWs. A strong correlation between reducing the diameter of the NWs with the decrease of the length of the poly-crystalline segment and the enhancement of the effective magnetic anisotropy has been shown. Magnetization curves obtained from alternating gradient magnetometry experiments show that the average ME anisotropy results from the competition between the magnetic anisotropies of both crystalline segments of the NWs. Understanding the influence of size and confinement effects on the magnetic properties of nanocomposites is of prime interest for the development of novel and agile devices.

This report presents simulation comparisons between an antipodal planar dipole (resonant at 450 MHz) and 3 different meander structures: square, sinusoidal, and triangular. The 3 different structures demonstrate the effect that different meander trace structures can have on size reduction, gain, reflection coefficient, and bandwidth. The meanders were designed first with a circuit equivalent. The results between the 3 structures show that for size reduction the square meander is the preferred method at 27.5% but it reduces the bandwidth by 22.37% with a loss in matching of 4.36 dB and gain loss of 0.26 dBi. The sinusoidal meander shows a size reduction of 23.04% and a bandwidth reduction of 12.9% with a loss in reflection coefficient by 0.48 dB and a loss in gain by about 0.14 dBi. The triangular meander shows the best results for the gain and reflection coefficient, while only having a size reduction of 19.82%. The triangular meander reduces the bandwidth by 16.0% with an improvement in matching by 0.69 dB and a loss of gain by 0.09 dBi. Ultimately, the preferred meander structure depends upon the application., The original document contains color images.

In 2004 there were not available standardized methods of reducing a large sample of hot mix asphalt and the quartering methods for aggregates were taken as reference, but these do not take into account the temperature at which the mix should be heated to ensure workability and the way to not affect the properties of the mixture within other details. It is for this reason that LanammeUCR implemented a completely new method to be able to certify the sampling of hot mix asphalt in the truck transports, so this study was used to include the quartering method to show that the sub-samples are representative of the lot. An experimental design was developed which included the new quartering method for multiple sampling boxes and then measure the asphalt content and gradation with the ignition test for each subsample and also the maximum theoretical specific gravity was performed, it was shown that with this method it is possible to obtain representative subsamples with good repeatability and also found that the segregation of the mixture was eliminated using the gutter system that in one step the desired subsamples are obtained. This method has 11 years of implementation and the advantages over the standard method AASHTO R 47, published in 2008, is that in this approach the care that must be taken when handling hot mix asphalt are detailed, such as the temperatures at which the sample must be heated and the heating times are established as this significantly affects the material properties. Besides the use of simple hand tools that are easy and economical to manufacture they take into account an ergonomic criteria to ensure that the procedure was safe and practical., Para el año 2004 no se contaba con métodos de reducción de muestra para mezcla asfáltica en caliente estandarizados y se tomaban como referencia los métodos de cuarteo para agregados pero estos no indicaban obviamente la temperatura a la cual se debía calentar la muestra para asegurar su trabajabilidad y que no afectara las propiedades de la mezcla entre otros detalles. Es por esta razón que, el LanammeUCR implementó un método totalmente nuevo para poder certificar el muestreo de mezcla asfáltica en caliente en vagoneta, por lo que se aprovechó este estudio para incluir el método de cuarteo para demostrar que las submuestras son representativas del lote de muestra.Se realizó un diseño experimental el cual incluía la realización del método de cuarteo para varias cajas de mezcla y luego medir la granulometría y el contenido de asfalto con el ensayo de ignición para cada submuestra así como el ensayo de gravedad específica máxima teórica, se demostró que con este método sí es posible obtener submuestras representativas del lote con buena repetibilidad y además se comprobó que la segregación de la mezcla se eliminó con el uso de la canaleta además de que se obtienen las submuestras deseadas en un solo paso.Este método tiene 11 años de implementado y las ventajas sobre el método estándar AASHTO R 47 publicado en el año 2008 es que, en este método se detallan los cuidados que se tienen que tomar en cuenta a la hora de manipular la mezcla asfáltica en caliente, tales como las temperaturas a las que se tiene que calentar la muestra y los tiempos de calentamiento pues esto afecta de manera significativa las propiedades del material. Además se incluye el uso de herramientas manuales muy simples que son de fácil fabricación y económicas que tomaron en cuenta el criterio de ergonomía para asegurar que el procedimiento fuese seguro y práctico.

In 2004 there were not available standardized methods of reducing a large sample of hot mix asphalt and the quartering methods for aggregates were taken as reference, but these do not take into account the temperature at which the mix should be heated to ensure workability and the way to not affect the properties of the mixture within other details. It is for this reason that LanammeUCR implemented a completely new method to be able to certify the sampling of hot mix asphalt in the truck transports, so this study was used to include the quartering method to show that the sub-samples are representative of the lot. An experimental design was developed which included the new quartering method for multiple sampling boxes and then measure the asphalt content and gradation with the ignition test for each subsample and also the maximum theoretical specific gravity was performed, it was shown that with this method it is possible to obtain representative subsamples with good repeatability and also found that the segregation of the mixture was eliminated using the gutter system that in one step the desired subsamples are obtained. This method has 11 years of implementation and the advantages over the standard method AASHTO R 47, published in 2008, is that in this approach the care that must be taken when handling hot mix asphalt are detailed, such as the temperatures at which the sample must be heated and the heating times are established as this significantly affects the material properties. Besides the use of simple hand tools that are easy and economical to manufacture they take into account an ergonomic criteria to ensure that the procedure was safe and practical., Para el año 2004 no se contaba con métodos de reducción de muestra para mezcla asfáltica en caliente estandarizados y se tomaban como referencia los métodos de cuarteo para agregados pero estos no indicaban obviamente la temperatura a la cual se debía calentar la muestra para asegurar su trabajabilidad y que no afectara las propiedades de la mezcla entre otros detalles. Es por esta razón que, el LanammeUCR implementó un método totalmente nuevo para poder certificar el muestreo de mezcla asfáltica en caliente en vagoneta, por lo que se aprovechó este estudio para incluir el método de cuarteo para demostrar que las submuestras son representativas del lote de muestra.Se realizó un diseño experimental el cual incluía la realización del método de cuarteo para varias cajas de mezcla y luego medir la granulometría y el contenido de asfalto con el ensayo de ignición para cada submuestra así como el ensayo de gravedad específica máxima teórica, se demostró que con este método sí es posible obtener submuestras representativas del lote con buena repetibilidad y además se comprobó que la segregación de la mezcla se eliminó con el uso de la canaleta además de que se obtienen las submuestras deseadas en un solo paso.Este método tiene 11 años de implementado y las ventajas sobre el método estándar AASHTO R 47 publicado en el año 2008 es que, en este método se detallan los cuidados que se tienen que tomar en cuenta a la hora de manipular la mezcla asfáltica en caliente, tales como las temperaturas a las que se tiene que calentar la muestra y los tiempos de calentamiento pues esto afecta de manera significativa las propiedades del material. Además se incluye el uso de herramientas manuales muy simples que son de fácil fabricación y económicas que tomaron en cuenta el criterio de ergonomía para asegurar que el procedimiento fuese seguro y práctico.

The design of a small ultra-high frequency (UHF) antenna for an ultra-wideband (UWB) random noise radar (RNR) system was undertaken to improve system bandwidth and reduce overall system size. The Vivaldi dipole antenna class showed the greatest potential for high performance in this specific application. After extensive computer simulation, three designs were built using two printed circuit board antenna construction methods. The antipodal chopped Vivaldi dipole antenna, built with a milling machine, achieved a wider bandwidth and more uniform spectral performance characteristics. Though current results show improvement over the current log-periodic antenna (LPA) used on the system, greater performance could possibly be achieved with higher fidelity construction methods. The chopped Vivaldi dipole antenna can be classified as a highly efficient, electrically small antenna optimized for UWB applications, due to the combination of small size as well as a nearly uniform frequency response and low dispersion in the UHF bandwidth. Though designed for AFIT's Noise Network (NoNET) system, a UHF UWB RNR, the antenna could be applied to a variety of UHF systems looking to optimize the trade-off between size and power budgets., The original document contains color images.

Modern commercial and military vehicles are equipped with more electrical accessories and demand more power than ever before. This causes an increase in the weight of the battery as well as drives the battery to end of life when the vehicle is stationary with the engine off. Lithium ion batteries, which are known for their high power and energy to weight density, long cycle life, and low self-discharge rate, are considered to be an alternative for the replacement of existing Starting, Lighting, and Ignition (SLI) lead acid batteries. Lithium ion battery chemistry offers double the reserve time of the stock battery and a significantly greater number of charging and discharging cycles while providing weight savings. There is no acid inside a lithium ion battery to cause corrosion, which eliminates potential damage to a vehicle from chemical spills and poisonous gases. Due to the slim cylindrical nature of many lithium ion cells, the battery design can be customized in order to fit a space claim in the vehicle. However, the characteristics, including the charge and discharge control of lithium ion battery chemistries, are different from those of flooded and sealed lead acid batteries. The traditional continuous battery charging approach may potentially result in overcharge and thus raise safety concerns for lithium ion battery replacement. In addition, lithium ion batteries experience reduced battery service life when exposed to very low and deep discharge levels. These and other technical challenges of 14V/28V lithium ion battery alternatives charging/discharging control will be discussed. In addition, cost comparisons and safety considerations for different lithium ion battery chemistries for lead acid battery replacement are included in this paper., Submitted to 2011 SAE International Conference.

The performance of MEMS inertial technology has evolved from automotive quality to that approaching tactical-grade quality (1 deg/h, 1 mg). This evolution is a direct result of advances made in the key technology areas driven by gun-launched projectile requirements. The application of silicon MEMS inertial technology to competent munitions efforts began in the early 1990s. Initially, gun hardness was demonstrated at the sensor level, although the bias-and-scale factor of these gyros and accelerometers was mostly suitable for automotive or commercial use. Subsequently, development programs were initiated to develop gun-hard inertial systems with greatly improved sensor performance, and with a goal of low production cost. This paper discusses the evolution of low-cost MEMS inertial system technology development for guided projectile INS/GPS systems and high performance IMUs. The evolution in sensors and packaging to realize performance improvement and system size reduction are presented. Recent data from the culmination of a three-year effort to develop an 8 cu in IMU are summarized, and represent the highest performance to date for an all-silicon IMU. Further investments in Silicon MEMS systems will ultimately realize IMUs that are smaller (less than 2 in (33 cc), higher performing (1 deg/h and less than 1 mg), and lower in cost (less than $1200 per IMU and $1500 per INS/GPS) than is achievable in any competing technology., This paper is an update of a paper presented at NATO Lecture Series SET-064 in October 2003 and May 2004 and Lecture Series SET 116 in October/November 2008 and March 2009. See also ADA569232, Low-Cost Navigation Sensors and Integration Technology (Capteurs de navigation a faible cout et technologie d'integration), RTO-EN-SET-116(2010).

From the 1970s to 1990s, a reduction in the body size of Japanese chum salmon (Oncorhynchus keta) was observed. To investigate this body size reduction in the North Pacific, we developed a bioenergetics model for chum salmon coupled with the results from a lower trophic ecosystem model embedded into a three-dimensional global model. In the bioenergetics model, respiration and consumption terms are assumed to be functions of water temperature and prey zooplankton density, which are the determining factors of the reduction of body size. The model reproduced the body size of the 1972 and 1991 year classes of chum salmon. The reproduced body size of the 1972 year class was larger than that of 1991 year class, and this result agrees with observations from the Bering Sea. Our model also reproduced the body size trend from l970 to 2000. The prey density, especially in the eastern North Pacific, had a greater influence on the change of body size than did the SST. This suggests that the size reduction of Japanese chum salmon in the 1990s was partly affected by changes in prey zooplankton density. In the context of the global warming scenario, we discuss changes in the migration route of chum salmon and predict that the population of Japanese chum salmon experience significant declines over this century.

From the 1970s to 1990s, a reduction in the body size of Japanese chum salmon (Oncorhynchus keta) was observed. To investigate this body size reduction in the North Pacific, we developed a bioenergetics model for chum salmon coupled with the results from a lower trophic ecosystem model embedded into a three-dimensional global model. In the bioenergetics model, respiration and consumption terms are assumed to be functions of water temperature and prey zooplankton density, which are the determining factors of the reduction of body size. The model reproduced the body size of the 1972 and 1991 year classes of chum salmon. The reproduced body size of the 1972 year class was larger than that of 1991 year class, and this result agrees with observations from the Bering Sea. Our model also reproduced the body size trend from l970 to 2000. The prey density, especially in the eastern North Pacific, had a greater influence on the change of body size than did the SST. This suggests that the size reduction of Japanese chum salmon in the 1990s was partly affected by changes in prey zooplankton density. In the context of the global warming scenario, we discuss changes in the migration route of chum salmon and predict that the population of Japanese chum salmon experience significant declines over this century.

A novel tunable planar inverted-F antenna (PIFA) is described. A via-patch is introduced under the main radiating element to create a capacitive coupling effect and lower the operating frequency. The antenna size is reduced by half when compared to the conventional PIFA. Incorporating with an L-shaped opening on the ground plane, the proposed via-patch loaded PIFA exhibits a 10-dB return-loss bandwidth of 8.91% for 2.4 GHz ISM band applications. In the proposed approach, the capacitive patch is connected to the ground through a via while a coaxial feed is directly connected to the radiating element. This is different from other capacitive-loading, size-reduction schemes in which the capacitive patch is connected to the coaxial feed, thus not able to provide frequency tuning. By simply replacing the via in our antenna with a screw and adjusting the height of the via-patch by turning the screw, a tuning range of 0.8 GHz from 2.5-3.3 GHz can be achieved. This makes the proposed PIFA a convenient tunable small antenna. Both simulation and measurement results are presented together with parametric studies on the via-patch and L-shaped opening ground plane. © 2007 IEEE.

A novel tunable planar inverted-F antenna (PIFA) is described. A via-patch is introduced under the main radiating element to create a capacitive coupling effect and lower the operating frequency. The antenna size is reduced by half when compared to the conventional PIFA. Incorporating with an L-shaped opening on the ground plane, the proposed via-patch loaded PIFA exhibits a 10-dB return-loss bandwidth of 8.91% for 2.4 GHz ISM band applications. In the proposed approach, the capacitive patch is connected to the ground through a via while a coaxial feed is directly connected to the radiating element. This is different from other capacitive-loading, size-reduction schemes in which the capacitive patch is connected to the coaxial feed, thus not able to provide frequency tuning. By simply replacing the via in our antenna with a screw and adjusting the height of the via-patch by turning the screw, a tuning range of 0.8 GHz from 2.5-3.3 GHz can be achieved. This makes the proposed PIFA a convenient tunable small antenna. Both simulation and measurement results are presented together with parametric studies on the via-patch and L-shaped opening ground plane. © 2007 IEEE.

A novel tunable planar inverted-F antenna (PIFA) is described. A via-patch is introduced under the main radiating element to create a capacitive coupling effect and lower the operating frequency. The antenna size is reduced by half when compared to the conventional PIFA. Incorporating with an L-shaped opening on the ground plane, the proposed via-patch loaded PIFA exhibits a 10-dB return-loss bandwidth of 8.91% for 2.4 GHz ISM band applications. In the proposed approach, the capacitive patch is connected to the ground through a via while a coaxial feed is directly connected to the radiating element. This is different from other capacitive-loading, size-reduction schemes in which the capacitive patch is connected to the coaxial feed, thus not able to provide frequency tuning. By simply replacing the via in our antenna with a screw and adjusting the height of the via-patch by turning the screw, a tuning range of 0.8 GHz from 2.5-3.3 GHz can be achieved. This makes the proposed PIFA a convenient tunable small antenna. Both simulation and measurement results are presented together with parametric studies on the via-patch and L-shaped opening ground plane. © 2007 IEEE.

Herbaceous biomass can be obtained using delayed harvesting method with moisture content less than 15% and directly densified without drying. Size reduction experiments of common reed stalks as cutting, flattening and densification have been carried out. As the result of reed stalk flattening, more than 8 strips can be obtained from this tubular structure. Average energy consumption 273 – 380 J kg-1 had been stated for reed stalk flattening. Specific cutting energy Escq value varies in 8 – 16 kJ m-2 in dependence of punch orientation angle according cross-section of reed specimen. Specific cutting energy for flattened stalk materials for reed density 600 kg m-3, varies Esc=13.3 – 27 J m kg-1. Densification experiments of compositions from peat particles, coarse wheat stalk and reed material particles from (1 - 2 mm) group with pressure 230 MPa indicated influence of peat proportion. Density 1.0 g cm-3 has been obtained in densification of straw stalk material particle compositions with peat, if peat proportion exceeds 20%.

The properties of the Koch island fractal boundary microstrip patch antenna are presented. The behavior at the fundamental mode and the existence of high-order modes that exhibit localized current density distributions is discussed. The main features are the size reduction of the patch resonating at the fundamental frequency when compared to Euclidean-shaped patches, and the application of localized modes in designing microstrip patch antennas with directive patterns., Peer Reviewed

A study was conducted to determine the amount of reduction that could be imposed upon the size of symbology and scales used on the A-10 aircraft head-up-display (HUD). Four symbology and scale sizes were selected for study: 1) the current A-10 HUD display size; 2) a 15% reduction of the current display size; 3) a 30% reduction; and (4) a 45% reduction of the current display size. Twelve subjects 'flew' 15 two-minute, air-to-ground missions under three ambient background conditions -- 5 missions at 3000 foot-Lamberts (ft-l); 5 missions at 2000 ft-L; and 5 at 0.001 ft-L. During a given mission, the subject performed an information call out task (primary) and a compensatory tracking task (secondary) . Findings from this study indicate that within the range of symbology sizes used, no significant differences in performance were noted. Subjects responded rapidly and accurately, regardless of the symbology size used. Keywords: Attack bombers; Human factors engineering; Head-up display symbology; Operator performance; Luminance.

This paper briefly discusses the need for electrically short antennas in the combat maneuver units of the modern field army. A brief history of the work done in the field of helical antennas is presented. An approximate mathematical development is presented which describes the radiation fields of the thin normal mode helical antenna. From the radiation fields, the equations for the polarization ratio and the radiation resistance are developed. A possible design for a tactical VHF-FM antenna to cover the frequency range 30-76 MHZ is presented. The design technique is discussed in detail and a calculator program for computing the input impedance is given. The results of experimental testing are presented and recommendations for improvement are given. (Author)

Poly(tri-n-butyltin) methacrylate, an anti-fouling compound, is prepared by esterifying a cross-linked polymethacrylic acid with tributyltin oxide in the presence of a poly solvent. The poly solvent, such as acetone, dioxane or methyl-ethyl ketone, causes particle size reduction due to hydraulic shattering. The in-reaction particle size reduction eliminates the need for mechanical post grinding in the current process., Supersedes PAT-APPL-609 940-84, AD-D011 313.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

Při reprezentaci objektů pomocí polygonálních modelů často vznikají modely obsahující velmi vysoké množství polygonů. Pokud chceme pracovat s takovým modelem v reálném čase, tak je nutné ho zjednodušit.Proces zjednodušování modelu se nazývá decimace. Je známých několik decimačních metod pro zjednodušení modelů. Podle charakteristiky modelu a požadovaných vlastností zjednodušenného modelu chceme vybrat vhodnou metodu, proto je nutné znát vlastnosti jednotlivých metod a také jejich omezení., When representing objects with polygonal models, we must often use models consisting of large number of polygons. If we want to work in real time with such model the model must be simplificated. The process of simplification is called decimation. We know several decimation techniques for simplification of models. According to characteristics of model and target features of simplified model, we want to choose suitable method. So we need to know characteristics of particular methods and also their limits.

With increasing use of biomass in pulverized fuel coal fired power stations, the impact of mill type on biomass size and shape is fundamental in optimizing mill and burner performance. The impact of mill type on the energy consumption, particle size and particle shape of four different biomasses commonly combusted in pulverized fuel boilers was investigated in this paper. Miscanthus, mixed wood, and steam exploded pellets, along with powdered olive cake, were comminuted in a planetary ball mill, Bond ball mill and cutting mill. For pelletized miscanthus, milling showed little impact on the particle size and shape of the pellets, with the milling action only reducing the pellets back to their original particle size distribution. This was also observed for the steam exploded pellets and mixed wood pellets in the cutting mill. For non-densified biomasses, such as olive cake, fines below the screen size should be removed before milling in a hammer mill as they pass straight through the mill, resulting in wasted mill capacity and energy consumption. Pellets should be composed of particles close to the required size for conveyance and combustions, and sphericity and roundness are crucial in determining this size. Olive cake showed the most spherical and round particles, but a coarser milled product size than the steam exploded pellets. Miscanthus and mixed wood pellets showed needle like shape profiles, as well as similar particle size distributions. Optimization of the particle size based on the Stokes shape factor is key to optimizing mill, conveyance and burner performance.

With increasing use of biomass in pulverized fuel coal fired power stations, the impact of mill type on biomass size and shape is fundamental in optimizing mill and burner performance. The impact of mill type on the energy consumption, particle size and particle shape of four different biomasses commonly combusted in pulverized fuel boilers was investigated in this paper. Miscanthus, mixed wood, and steam exploded pellets, along with powdered olive cake, were comminuted in a planetary ball mill, Bond ball mill and cutting mill. For pelletized miscanthus, milling showed little impact on the particle size and shape of the pellets, with the milling action only reducing the pellets back to their original particle size distribution. This was also observed for the steam exploded pellets and mixed wood pellets in the cutting mill. For non-densified biomasses, such as olive cake, fines below the screen size should be removed before milling in a hammer mill as they pass straight through the mill, resulting in wasted mill capacity and energy consumption. Pellets should be composed of particles close to the required size for conveyance and combustions, and sphericity and roundness are crucial in determining this size. Olive cake showed the most spherical and round particles, but a coarser milled product size than the steam exploded pellets. Miscanthus and mixed wood pellets showed needle like shape profiles, as well as similar particle size distributions. Optimization of the particle size based on the Stokes shape factor is key to optimizing mill, conveyance and burner performance.

With increasing use of biomass in pulverized fuel coal fired power stations, the impact of mill type on biomass size and shape is fundamental in optimizing mill and burner performance. The impact of mill type on the energy consumption, particle size and particle shape of four different biomasses commonly combusted in pulverized fuel boilers was investigated in this paper. Miscanthus, mixed wood, and steam exploded pellets, along with powdered olive cake, were comminuted in a planetary ball mill, Bond ball mill and cutting mill. For pelletized miscanthus, milling showed little impact on the particle size and shape of the pellets, with the milling action only reducing the pellets back to their original particle size distribution. This was also observed for the steam exploded pellets and mixed wood pellets in the cutting mill. For non-densified biomasses, such as olive cake, fines below the screen size should be removed before milling in a hammer mill as they pass straight through the mill, resulting in wasted mill capacity and energy consumption. Pellets should be composed of particles close to the required size for conveyance and combustions, and sphericity and roundness are crucial in determining this size. Olive cake showed the most spherical and round particles, but a coarser milled product size than the steam exploded pellets. Miscanthus and mixed wood pellets showed needle like shape profiles, as well as similar particle size distributions. Optimization of the particle size based on the Stokes shape factor is key to optimizing mill, conveyance and burner performance.