987 resultados para Extragalactic Distance Scale
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Objective: To evaluate the possible association between the scale of Alvarado (EA) and macroscopic appearance (MA) of the appendix in patients with acute appendicitis.Methods: after receiving the diagnosis of acute appendicitis, EA data were collected. During appendectomy, MA data were collected. Data from patients without appendicitis were excluded. The Spearman correlation test was used to compare EA with Appendix MA (p < 0.05). Other variables were represented by simple frequency. The confidence interval (CI) of 95% was calculated for the correlation test.Results: Data were collected from 67 consecutive patients. The mean age was 37.1 ± 12.5 years and 77.6% of patients were male. The Spearman correlation test used for EA and MA was + 0.77 (95% CI 0.65-0.85, p < 0.0001).Conclusion: although correlation was not perfect, our data indicate that a high score on the scale of Alvarado in patients with appendicitis is correlated with advanced stages of the inflammatory process of acute appendicitis.
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This thesis presents an approach for formulating and validating a space averaged drag model for coarse mesh simulations of gas-solid flows in fluidized beds using the two-fluid model. Proper modeling for fluid dynamics is central in understanding any industrial multiphase flow. The gas-solid flows in fluidized beds are heterogeneous and usually simulated with the Eulerian description of phases. Such a description requires the usage of fine meshes and small time steps for the proper prediction of its hydrodynamics. Such constraint on the mesh and time step size results in a large number of control volumes and long computational times which are unaffordable for simulations of large scale fluidized beds. If proper closure models are not included, coarse mesh simulations for fluidized beds do not give reasonable results. The coarse mesh simulation fails to resolve the mesoscale structures and results in uniform solids concentration profiles. For a circulating fluidized bed riser, such predicted profiles result in a higher drag force between the gas and solid phase and also overestimated solids mass flux at the outlet. Thus, there is a need to formulate the closure correlations which can accurately predict the hydrodynamics using coarse meshes. This thesis uses the space averaging modeling approach in the formulation of closure models for coarse mesh simulations of the gas-solid flow in fluidized beds using Geldart group B particles. In the analysis of formulating the closure correlation for space averaged drag model, the main parameters for the modeling were found to be the averaging size, solid volume fraction, and distance from the wall. The closure model for the gas-solid drag force was formulated and validated for coarse mesh simulations of the riser, which showed the verification of this modeling approach. Coarse mesh simulations using the corrected drag model resulted in lowered values of solids mass flux. Such an approach is a promising tool in the formulation of appropriate closure models which can be used in coarse mesh simulations of large scale fluidized beds.
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Tämän tutkimuksen tavoitteena oli nykyisin tuotantokäytössä olevan rullaoikaisukoneen automatisointi ja uuden oikaisukonekokonaisuuden mitoitus tulevaisuuden materiaaliominaisuuksien perusteella. Automatisoinnilla on tarkoitus nykyisessä käytössä helpottaa nauhahitsaajan työtä ja lähitulevaisuudessa optimoida romutustarvetta kelojen keula- ja häntäalueilla. Uuden oikaisukonekokonaisuuden osalta työssä on määritetty rullaoikaisukoneen rullakoot, rullien keskiöetäisyys, vaadittava moottoriteho ja rullien tuennan tarve sekä erillisen hilseenmurskaimen/rullavenytysoikaisukoneen tarve peittauslinjan toiminnassa. Rullaoikaisukoneen asetusarvojen laskeminen toteutettiin ympyräkaarimenetelmää ja seurantatutkimusta käyttäen. Ensimmäisen ylärullan asetteluarvot on laskettu suorilla kaavasovelluksilla. Toisen ylärullan kohdalla oli tarpeellista tehdä laajempaa seurantatutkimusta, jotta löydettiin sellainen tapa, jolla myös sen arvot saataisiin riippuvaiseksi ensimmäisen ylärullan asetteluarvoista ja ympyränkaarimenetelmästä. Uutta oikaisukonekokonaisuutta varten suoritettujen laskelmien perusteella rullaoikaisukoneen telakokoa ja keskiöetäisyyttä on pienennettävä, moottoritehoa on kasvatettava ja työrullien tuentaa on parannettava verrattuna nykyiseen tuotantokoneeseen. Esioikaisukonetyyppisen rullaoikaisukoneen rajoittuneesta oikaisutuloksesta ja tietyillä kelalaaduilla esiintyvä erittäin luja wüstiittihilse puoltaa vahvasti erillisen hilseenmurskaimen lisäämistä peittauslinjan konekantaan.
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ResumoOBJETIVOValidar o instrumento Body Image Relationship Scale (BIRS) em mulheres brasileiras acometidas pelo câncer de mamaMÉTODOSO instrumento foi aplicado por entrevistadoras treinadas em 139 usuárias do Sistema Único de Saúde que foram submetidas aos tratamentos do câncer entre 2006 e 2010. O instrumento foi aferido considerando-se a consistência interna e a confiabilidade. Para efeito de comparação as técnicas de análise fatorial utilizadas no artigo original foram aplicadasRESULTADOSO valor de correlação Spearman-Brown foi 0,8, o que indica alto nível de confiabilidade, e o alfa de Cronbach encontrado foi 0,9, indicando alto nível de consistência interna. A análise fatorial mostrou que quatro questões não tinham poder discriminatório e carga fatorial baixa e outras cinco foram realocadas em outros domínios. Dessa forma, foi aplicada e mostrou variabilidade semelhante ao instrumento originalCONCLUSÃOA versão brasileira do BIRS, renomeada como Escala de Relacionamento e Imagem Corporal (ERIC), apresentou evidências de adequada confiabilidade e consistência interna, o que torna esse instrumento recomendável para aplicação em mulheres brasileiras com câncer de mama, apesar de alguns poucos limites
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Currently, a high penetration level of Distributed Generations (DGs) has been observed in the Danish distribution systems, and even more DGs are foreseen to be present in the upcoming years. How to utilize them for maintaining the security of the power supply under the emergency situations, has been of great interest for study. This master project is intended to develop a control architecture for studying purposes of distribution systems with large scale integration of solar power. As part of the EcoGrid EU Smart Grid project, it focuses on the system modelling and simulation of a Danish representative LV network located in Bornholm island. Regarding the control architecture, two types of reactive control techniques are implemented and compare. In addition, a network voltage control based on a tap changer transformer is tested. The optimized results after applying a genetic algorithm to five typical Danish domestic loads are lower power losses and voltage deviation using Q(U) control, specially with large consumptions. Finally, a communication and information exchange system is developed with the objective of regulating the reactive power and thereby, the network voltage remotely and real-time. Validation test of the simulated parameters are performed as well.
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The agouti is a species intensively hunted throughout the Amazon and the semi-arid regions of northeastern Brazil. Considering the current trend in conservation management of wild species, the aim of this study was to determine the morphometric reference to the heart of agouti raised in captivity, based on thoracic and cardiac measurements in these animals. Thirty adult agoutis, 1 to 3 years of age, without clinical signs of cardiac disease were selected. The animals were physically restrained and radiographies in laterolateral (LL) and ventrodorsal (VD) recumbence were produced. The following measures were taken: the apicobasilar length of the heart (at the most cranial height of the Carina region to the heart apex) (AB), maximum width of the heart perpendicular to AB (CD), heart inclination angle (AIC), trachea inclination angle (AIT), distance from the right heart wall (DPTd), distance from the left heart wall (DPTe) and vertical depth of the thorax, and the ventral face of the vertebral column to the dorsal border of the sternum at the level of the trachea bifurcation (H). The ratios between AB/CD, AB/H and CD/H were also analyzed. To calculate the vertebral heart scale (VHS), the AB and CD measurements were laid over the thoracic vertebra starting at T4. Radiographic evaluation showed values consistent with those reported in small animals and some wild and exotic species. The main biometric values in the chest cavity and heart of agouti are arranged as follows: (1) The ratios between AB/H ratio and CD/H were not sensitive for identifying heart increases (p>0.05), while the ratio AB/CD was more sensitive in this identification (p<0.05); (2) AIC: 21.2±6.4º (mean between male and famale); (3) AIT for males and females: 9.93±3.23° and 8.4±3.94°; (4) DPTd and DPTe for males: 0.97±0.40cm and 0.7±0.30cm; (5) DPTd and DPTe for females: 1.12±0.42cm and 01.02±0.43cm; (6) VHS for males and females: 7.75±0.48v e 7.61±0.34v; (7) The caudal vena cava (CVC) was visualized dorsal-cranially and located right of the midline. The data obtained allowed the acquisition of the first reference values for biometry of the heart of agoutis, contributing to better understanding of cardiac morphology and identification of cardiomyopathy in these animals.
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Auditor independence is a cornerstone of the auditing profession and the basic principle that underpins the reputation of the auditing profession in the public eye. Indeed, it is the attribute most demanded from auditors by the public. Therefore, the sustainability of the auditing profession depends on how auditors can protect this principle. This dissertation consists of four interrelated essays concerned with auditor independence. Specifically, it examines situations that can threaten and impair auditor independence. In addition, this dissertation also examines several variables that may enhance and protect auditor independence. The first essay aims to examine the impact of social pressures occurring within audit firms on auditors’ judgment in the setting of a society with “high power distance” and “low individualism” cultural dimensions. The social pressures consisted of obedience pressure exerted by an auditor’s superior and conformity pressure exerted by an auditor’s colleague. Moreover, two moderating variables—a multi-dimensional professional commitment and locus of control—were included as moderator variables in the relationship between the social pressures faced by auditors and their judgment. The findings show that obedience and conformity pressures influence auditor judgment. Auditors who face the social pressures will make a judgment that may be even diametrically opposite to the independence principle. The findings also indicate that a multi-dimensional professional commitment and locus of control may potentially influence auditor judgment in a situation with social pressures. The second essay aims to investigate the association of advocacy and familiarity threats caused by auditor fee dependence and auditor tenure on auditor independence based on Finnish data, law, and auditing environment. This essay was motivated by the Green Paper on Audit Policy, published by the European Commission in 2010 that questions whether the maximum fee collected from a client should be regulated and whether consecutive assignments should be limited, among others. Contrary to popular belief, this essay does not find evidence that audit fees and long auditor tenure will jeopardise auditor independence. Therefore, the findings do not support policies to regulate auditor fees or limit auditor tenure in Finland. The third essay aims to examine the effect of client intimidation on auditor independence in an audit-client conflict situation. Intimidation threat is one of five independence threats that are explicitly referenced in the IFAC’s independence framework. Client intimidation was manifested in the client threatening to replace the auditor if the auditor did not adopt the client’s position. In addition, this essay examines the role of auditor’s perceived pressure and multi-dimensions of professional commitment as moderator variables. The findings suggest that auditors who experience client intimidation in an audit conflict situation are more likely to have their independence impaired than those who are in a similar situation but without client intimidation. Moreover, auditors who experience client intimidation perceive higher pressure than those who do not experience intimidation. Finally, auditors’ affective and continuance professional commitment dimensions moderate the relationship between auditors’ perceived pressures and auditor independence. The aim of the fourth essay is twofold. First, it aims to develop a scale for measuring auditors’ reputation awareness. Second, it aims to examine the correlation between the levels of auditor reputation awareness and auditor independence. A seven-item scale was developed as the reputation awareness scale. The findings indicate that the scale consists of one dimension. It also has a level of satisfactory reliability and a high level of validity. The findings show that there is a positive correlation between the level of auditors’ reputation awareness and auditor independence.
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Detta arbete fokuserar på modellering av katalytiska gas-vätskereaktioner som genomförs i kontinuerliga packade bäddar. Katalyserade gas-vätskereaktioner hör till de mest typiska reaktionerna i kemisk industri; därför behandlas här packade bäddreaktorer som ett av de populäraste alternativen, då kontinuerlig drift eftersträvas. Tack vare en stor katalysatormängd per volym har de en kompakt struktur, separering av katalysatorn behövs inte och genom en professionell design kan den mest fördelaktiga strömningsbilden upprätthållas i reaktorn. Packade bäddreaktorer är attraktiva p.g.a. lägre investerings- och driftskostnader. Även om packade bäddar används intensivt i industri, är det mycket utmanande att modellera. Detta beror på att tre faser samexisterar och systemets geometri är komplicerad. Existensen av flera reaktioner gör den matematiska modelleringen även mera krävande. Många förenklingar blir därmed nödvändiga. Modellerna involverar typiskt flera parametrar som skall justeras på basis av experimentella data. I detta arbete studerades fem olika reaktionssystem. Systemen hade studerats experimentellt i vårt laboratorium med målet att nå en hög produktivitet och selektivitet genom ett optimalt val av katalysatorer och driftsbetingelser. Hydrering av citral, dekarboxylering av fettsyror, direkt syntes av väteperoxid samt hydrering av sockermonomererna glukos och arabinos användes som exempelsystem. Även om dessa system hade mycket gemensamt, hade de också unika egenskaper och krävde därför en skräddarsydd matematisk behandling. Citralhydrering var ett system med en dominerande huvudreaktion som producerar citronellal och citronellol som huvudprodukter. Produkterna används som en citrondoftande komponent i parfymer, tvålar och tvättmedel samt som plattform-kemikalier. Dekarboxylering av stearinsyra var ett specialfall, för vilket en reaktionsväg för produktion av långkedjade kolväten utgående från fettsyror söktes. En synnerligen hög produktselektivitet var karakteristisk för detta system. Även processuppskalning modellerades för dekarboxylerings-reaktionen. Direkt syntes av väteperoxid hade som målsättning att framta en förenklad process att producera väteperoxid genom att låta upplöst väte och syre reagera direkt i ett lämpligt lösningsmedel på en aktiv fast katalysator. I detta system förekommer tre bireaktioner, vilka ger vatten som oönskad produkt. Alla dessa tre reaktioner modellerades matematiskt med hjälp av dynamiska massbalanser. Målet med hydrering av glukos och arabinos är att framställa produkter med en hög förädlingsgrad, nämligen sockeralkoholer, genom katalytisk hydrering. För dessa två system löstes ämnesmängd- och energibalanserna simultant för att evaluera effekter inne i porösa katalysatorpartiklar. Impulsbalanser som bestämmer strömningsbetingelser inne i en kemisk reaktor, ersattes i alla modelleringsstudier med semi-empiriska korrelationsuttryck för vätskans volymandel och tryckförlust och med axiell dispersionsmodell för beskrivning av omblandningseffekter. Genom att justera modellens parametrar kunde reaktorns beteende beskrivas väl. Alla experiment var genomförda i laboratorieskala. En stor mängd av kopplade effekter samexisterade: reaktionskinetik inklusive adsorption, katalysatordeaktivering, mass- och värmeöverföring samt strömningsrelaterade effekter. En del av dessa effekter kunde studeras separat (t.ex. dispersionseffekter och bireaktioner). Inverkan av vissa fenomen kunde ibland minimeras genom en noggrann planering av experimenten. På detta sätt kunde förenklingar i modellerna bättre motiveras. Alla system som studerades var industriellt relevanta. Utveckling av nya, förenklade produktionsteknologier för existerande kemiska komponenter eller nya komponenter är ett gigantiskt uppdrag. Studierna som presenterades här fokuserade på en av den teknisk-vetenskapliga utfärdens första etapper.
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The classical treatment of rough wall turbulent boundary layers consists in determining the effect the roughness has on the mean velocity profile. This effect is usually described in terms of the roughness function delta U+. The general implication is that different roughness geometries with the same delta U+ will have similar turbulence characteristics, at least at a sufficient distance from the roughness elements. Measurements over two different surface geometries (a mesh roughness and spanwise circular rods regularly spaced in the streamwise direction) with nominally the same delta U+ indicate significant differences in the Reynolds stresses, especially those involving the wall-normal velocity fluctuation, over the outer region. The differences are such that the Reynolds stress anisotropy is smaller over the mesh roughness than the rod roughness. The Reynolds stress anisotropy is largest for a smooth wall. The small-scale anisotropy and interniittency exhibit much smaller differences when the Taylor microscale Reynolds number and the Kolmogorov-normalized mean shear are nominally the same. There is nonetheless evidence that the small-scale structure over the three-dimensional mesh roughness conforms more closely with isotropy than that over the rod-roughened and smooth walls.
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A parallel pseudo-spectral method for the simulation in distributed memory computers of the shallow-water equations in primitive form was developed and used on the study of turbulent shallow-waters LES models for orographic subgrid-scale perturbations. The main characteristics of the code are: momentum equations integrated in time using an accurate pseudo-spectral technique; Eulerian treatment of advective terms; and parallelization of the code based on a domain decomposition technique. The parallel pseudo-spectral code is efficient on various architectures. It gives high performance onvector computers and good speedup on distributed memory systems. The code is being used for the study of the interaction mechanisms in shallow-water ows with regular as well as random orography with a prescribed spectrum of elevations. Simulations show the evolution of small scale vortical motions from the interaction of the large scale flow and the small-scale orographic perturbations. These interactions transfer energy from the large-scale motions to the small (usually unresolved) scales. The possibility of including the parametrization of this effects in turbulent LES subgrid-stress models for the shallow-water equations is addressed.
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Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by droplets formed by liquid atomisation, usually in the venturi throat. The size of the droplets formed is of fundamental importance to the performance of the equipment, both in terms of pressure drop and collection efficiency. In this study, drop sizes in a cylindrical laboratory scale venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90 m/s and 0.5 to 2.0 l/m3, respectively. Water was inserted as perpendicular jets at the beginning of the throat. Measurements were performed at three positions: two located along the throat, and the last one at the end of the diffuser. The data presented here are a typical example of pneumatic atomisation and can be relevant to other industrial applications such as combustion and engine technology. Finally, results are compared to available correlations and the validity of these equations is discussed.
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In the present work, liquid-solid flow in industrial scale is modeled using the commercial software of Computational Fluid Dynamics (CFD) ANSYS Fluent 14.5. In literature, there are few studies on liquid-solid flow in industrial scale, but any information about the particular case with modified geometry cannot be found. The aim of this thesis is to describe the strengths and weaknesses of the multiphase models, when a large-scale application is studied within liquid-solid flow, including the boundary-layer characteristics. The results indicate that the selection of the most appropriate multiphase model depends on the flow regime. Thus, careful estimations of the flow regime are recommended to be done before modeling. The computational tool is developed for this purpose during this thesis. The homogeneous multiphase model is valid only for homogeneous suspension, the discrete phase model (DPM) is recommended for homogeneous and heterogeneous suspension where pipe Froude number is greater than 1.0, while the mixture and Eulerian models are able to predict also flow regimes, where pipe Froude number is smaller than 1.0 and particles tend to settle. With increasing material density ratio and decreasing pipe Froude number, the Eulerian model gives the most accurate results, because it does not include simplifications in Navier-Stokes equations like the other models. In addition, the results indicate that the potential location of erosion in the pipe depends on material density ratio. Possible sedimentation of particles can cause erosion and increase pressure drop as well. In the pipe bend, especially secondary flows, perpendicular to the main flow, affect the location of erosion.
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This thesis investigates the influence of cultural distance on entrepreneurs’ negotiation behaviour. For this purpose, Turku was chosen as the unit of analysis due to the exponential demographic change experienced during the last two decades that has derived in a more diversified local environment. The research aim set for this study was to identify to what extent entrepreneurs face cultural distance, how cultural distance influences the entrepreneur’s negotiation behaviour and how can it be addressed in order to turn dissimilarities into opportunities. This study presented the relation and apparent dichotomy of cultural distance and global culture, including the component of diversity. The impact of cultural distance in the entrepreneurial mindset and its consequent effect in negotiation behaviour was presented too. Addressing questions about the way individuals perceive, behave and interact allowed the use of interviews for this qualitative research study. In the empirical part of this study it was found that negotiation behaviour differed in terms of how congenial entrepreneurs felt when managing cultural distance, encompassing their performance. It was also acknowledged that after time and effort, some of the personal traits were enhanced while others reduced, allowing for more flexibility and adaptation. Furthermore, depending on the level of trust and shared interests, entrepreneurs determined their attitudinal approach, being adaptive or reactive subject to situational aspects. Additionally, it was found that the acquisition of cultural savvy not necessarily conveyed to more creativity. This experiential learning capability led to the proposition of new ways of behaviour. Likewise, it was proposed that growing cultural intelligence bridge distances, reducing mistrusts and misunderstandings. The capability of building more collaborative relationships allows entrepreneurs to see cultural distance as a cultural perspective instead of as a threat. Therefore it was recommended to focus on proximity rather than distance to better identify and exploit untapped opportunities and better perform when negotiating in whichever cultural conditions.
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Global illumination algorithms are at the center of realistic image synthesis and account for non-trivial light transport and occlusion within scenes, such as indirect illumination, ambient occlusion, and environment lighting. Their computationally most difficult part is determining light source visibility at each visible scene point. Height fields, on the other hand, constitute an important special case of geometry and are mainly used to describe certain types of objects such as terrains and to map detailed geometry onto object surfaces. The geometry of an entire scene can also be approximated by treating the distance values of its camera projection as a screen-space height field. In order to shadow height fields from environment lights a horizon map is usually used to occlude incident light. We reduce the per-receiver time complexity of generating the horizon map on N N height fields from O(N) of the previous work to O(1) by using an algorithm that incrementally traverses the height field and reuses the information already gathered along the path of traversal. We also propose an accurate method to integrate the incident light within the limits given by the horizon map. Indirect illumination in height fields requires information about which other points are visible to each height field point. We present an algorithm to determine this intervisibility in a time complexity that matches the space complexity of the produced visibility information, which is in contrast to previous methods which scale in the height field size. As a result the amount of computation is reduced by two orders of magnitude in common use cases. Screen-space ambient obscurance methods approximate ambient obscurance from the depth bu er geometry and have been widely adopted by contemporary real-time applications. They work by sampling the screen-space geometry around each receiver point but have been previously limited to near- field effects because sampling a large radius quickly exceeds the render time budget. We present an algorithm that reduces the quadratic per-pixel complexity of previous methods to a linear complexity by line sweeping over the depth bu er and maintaining an internal representation of the processed geometry from which occluders can be efficiently queried. Another algorithm is presented to determine ambient obscurance from the entire depth bu er at each screen pixel. The algorithm scans the depth bu er in a quick pre-pass and locates important features in it, which are then used to evaluate the ambient obscurance integral accurately. We also propose an evaluation of the integral such that results within a few percent of the ray traced screen-space reference are obtained at real-time render times.
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Hydrothermal carbonization (HTC) is a thermochemical process used in the production of charred matter similar in composition to coal. It involves the use of wet, carbohydrate feedstock, a relatively low temperature environment (180 °C-350 °C) and high autogenous pressure (up to 2,4 MPa) in a closed system. Various applications of the solid char product exist, opening the way for a range of biomass feedstock materials to be exploited that have so far proven to be troublesome due to high water content or other factors. Sludge materials are investigated as candidates for industrial-scale HTC treatment in fuel production. In general, HTC treatment of pulp and paper industry sludge (PPS) and anaerobically digested municipal sewage sludge (ADS) using existing technology is competitive with traditional treatment options, which range in price from EUR 30-80 per ton of wet sludge. PPS and ADS can be treated by HTC for less than EUR 13 and 33, respectively. Opportunities and challenges related to HTC exist, as this relatively new technology moves from laboratory and pilot-scale production to an industrial scale. Feedstock materials, end-products, process conditions and local markets ultimately determine the feasibility of a given HTC operation. However, there is potential for sludge materials to be converted to sustainable bio-coal fuel in a Finnish context.