975 resultados para cost estimate


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surface. The effects of the content of W nanoparticles and reaction temperature on activity and selectivity for the partial hydrogenation of 3-hexyne, a non-terminal alkyne, were assessed under moderate conditions of temperature and pressure. The monometallic catalysts prepared were found to be active and stereoselective for the production of (Z )-3-hexene, had the following order: 7.1WN/A > 8.5 WN/A ≥ 4.5 WN/A. Additionally, the performance of the synthesized xWN/A catalysts exhibited high sensitivity to temperature variation. In all cases, the maximum 3-hexyne total conversion and selectivity was achieved at 323 K. The performance of the catalysts was considered to be a consequence of two phenomena: a) the electronic effects, related to the high charge of W (+6), causing an intensive dipole moment in the hydrogen molecule (van der Waals forces) and leading to heterolytic bond rupture; the H+ and H- species generated approach a 3-hexyne adsorbate molecule and cause heterolytic rupture of the C≡C bond into C- = C+; and b) steric effects related to the high concentration of WO3 on 8.5WN/A that block the Al2O3 support. Catalyst deactivation was detected, starting at about 50 min of reaction time. Electrodeficient W6+ species are responsible for the formation of green oil at the surface level, blocking pores and active sites of the catalyst, particularly at low reaction temperatures (293 and 303 K). The resulting best catalyst, 7.1WN/A, has low fabrication cost and high selectivity for (Z )-3-hexene (94%) at 323 K. This selectivity is comparable to that of the classical and more expensive industrial Lindlar catalyst (5 wt% Pd). The alumina supported tungsten catalysts are low-cost potential replacements for the Lindlar industrial catalyst. These catalysts could also be used for preparing bimetallic W-Pd catalysts for selective hydrogenation of terminal and non-terminal alkynes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To understand the physicochemical properties and catalytic activity during the pyrolysis of atmospheric petroleum residue, a template-free ZSM-5 zeolite was synthesized using a direct method without additional seeds or an organic structure director and compared with conventionally synthesized ZSM-5. The crystallinities of the two zeolites were evaluated by XRD and FTIR and were quite similar; however, structural analyses using SEM and argon physisorption revealed that the zeolites diverged in particle diameter and in the external surface area of the micropores. The synthesis procedure without a template incorporated additional aluminum into the crystalline network, according to ICP-AES and TPD NH3 experiments. The catalytic pyrolysis performed over the template-free ZSM-5 generated results comparable to those for pyrolysis performed over the conventional ZSM-5 according to its hydrocarbon distribution. The selectivity to aromatics compounds was exactly the same for both ZSM-5 zeolites, and these values stand out compared to thermal pyrolysis. The template-free ZSM-5 produced 20% of light hydrocarbons (C4-C6), where such compounds are olefins and paraffins of great interest to the petrochemical industry. Therefore, template-free ZSM-5 is promising for industrial use due to its lowered synthesis time, low-cost and significant distribution to light hydrocarbons.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The need for automated analyzers for industrial and environmental samples has triggered the research for new and cost-effective strategies of automation and control of analytical systems. The widespread availability of open-source hardware together with novel analytical methods based on pulsed flows have opened the possibility of implementing standalone automated analytical systems at low cost. Among the areas that can benefit from this approach are the analysis of industrial products and effluents and environmental analysis. In this work, a multi-pumping flow system is proposed for the determination of phosphorus in effluents and polluted water samples. The system employs photometric detection based on the formation of molybdovanadophosphoric acid, and the fluidic circuit is built using three solenoid micropumps. The detection is implemented with a low cost LED-photodiode photometric detection system and the whole system is controlled by an open-source Arduino Uno microcontroller board. The optimization of the timing to ensure the color development and the pumping cycle is discussed for the proposed implementation. Experimental results to evaluate the system behavior are presented verifying a linear relationship between the relative absorbance and the phosphorus concentrations for levels as high as 50 mg L-1.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The dissertation is based on four articles dealing with recalcitrant lignin water purification. Lignin, a complicated substance and recalcitrant to most treatment technologies, inhibits seriously pulp and paper industry waste management. Therefore, lignin is studied, using WO as a process method for its degradation. A special attention is paid to the improvement in biodegradability and the reduction of lignin content, since they have special importance for any following biological treatment. In most cases wet oxidation is not used as a complete ' mineralization method but as a pre treatment in order to eliminate toxic components and to reduce the high level of organics produced. The combination of wet oxidation with a biological treatment can be a good option due to its effectiveness and its relatively low technology cost. The literature part gives an overview of Advanced Oxidation Processes (AOPs). A hot oxidation process, wet oxidation (WO), is investigated in detail and is the AOP process used in the research. The background and main principles of wet oxidation, its industrial applications, the combination of wet oxidation with other water treatment technologies, principal reactions in WO, and key aspects of modelling and reaction kinetics are presented. There is also given a wood composition and lignin characterization (chemical composition, structure and origin), lignin containing waters, lignin degradation and reuse possibilities, and purification practices for lignin containing waters. The aim of the research was to investigate the effect of the operating conditions of WO, such as temperature, partial pressure of oxygen, pH and initial concentration of wastewater, on the efficiency, and to enhance the process and estimate optimal conditions for WO of recalcitrant lignin waters. Two different waters are studied (a lignin water model solution and debarking water from paper industry) to give as appropriate conditions as possible. Due to the great importance of re using and minimizing the residues of industries, further research is carried out using residual ash of an Estonian power plant as a catalyst in wet oxidation of lignin-containing water. Developing a kinetic model that includes in the prediction such parameters as TOC gives the opportunity to estimate the amount of emerging inorganic substances (degradation rate of waste) and not only the decrease of COD and BOD. The degradation target compound, lignin is included into the model through its COD value (CODligning). Such a kinetic model can be valuable in developing WO treatment processes for lignin containing waters, or other wastewaters containing one or more target compounds. In the first article, wet oxidation of "pure" lignin water was investigated as a model case with the aim of degrading lignin and enhancing water biodegradability. The experiments were performed at various temperatures (110 -190°C), partial oxygen pressures (0.5 -1.5 MPa) and pH (5, 9 and 12). The experiments showed that increasing the temperature notably improved the processes efficiency. 75% lignin reduction was detected at the lowest temperature tested and lignin removal improved to 100% at 190°C. The effect of temperature on the COD removal rate was lower, but clearly detectable. 53% of organics were oxidized at 190°C. The effect of pH occurred mostly on lignin removal. Increasing the pH enhanced the lignin removal efficiency from 60% to nearly 100%. A good biodegradability ratio (over 0.5) was generally achieved. The aim of the second article was to develop a mathematical model for "pure" lignin wet oxidation using lumped characteristics of water (COD, BOD, TOC) and lignin concentration. The model agreed well with the experimental data (R2 = 0.93 at pH 5 and 12) and concentration changes during wet oxidation followed adequately the experimental results. The model also showed correctly the trend of biodegradability (BOD/COD) changes. In the third article, the purpose of the research was to estimate optimal conditions for wet oxidation (WO) of debarking water from the paper industry. The WO experiments were' performed at various temperatures, partial oxygen pressures and pH. The experiments showed that lignin degradation and organics removal are affected remarkably by temperature and pH. 78-97% lignin reduction was detected at different WO conditions. Initial pH 12 caused faster removal of tannins/lignin content; but initial pH 5 was more effective for removal of total organics, represented by COD and TOC. Most of the decrease in organic substances concentrations occurred in the first 60 minutes. The aim of the fourth article was to compare the behaviour of two reaction kinetic models, based on experiments of wet oxidation of industrial debarking water under different conditions. The simpler model took into account only the changes in COD, BOD and TOC; the advanced model was similar to the model used in the second article. Comparing the results of the models, the second model was found to be more suitable for describing the kinetics of wet oxidation of debarking water. The significance of the reactions involved was compared on the basis of the model: for instance, lignin degraded first to other chemically oxidizable compounds rather than directly to biodegradable products. Catalytic wet oxidation of lignin containing waters is briefly presented at the end of the dissertation. Two completely different catalysts were used: a commercial Pt catalyst and waste power plant ash. CWO showed good performance using 1 g/L of residual ash gave lignin removal of 86% and COD removal of 39% at 150°C (a lower temperature and pressure than with WO). It was noted that the ash catalyst caused a remarkable removal rate for lignin degradation already during the pre heating for `zero' time, 58% of lignin was degraded. In general, wet oxidation is not recommended for use as a complete mineralization method, but as a pre treatment phase to eliminate toxic or difficultly biodegradable components and to reduce the high level of organics. Biological treatment is an appropriate post treatment method since easily biodegradable organic matter remains after the WO process. The combination of wet oxidation with subsequent biological treatment can be an effective option for the treatment of lignin containing waters.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Venäjän lainsäädäntö mahdollistaa erilaisten rajoitusten asettamisen liikenteelle kelirikkoajan aikana ja alhaisten painorajoitusten asettaminen on tällöin yleistä. Kelirikon aikaisiin rajoituksiin liittyvä lainsäädäntö on pääosin tarkoituksenmukainen, mutta sitä sovelletaan tavalla, jolla vaikeutetaan huomattavasti yritysten toimintaa ja tarvittavien kuljetusten järjestämistä. Diplomityössä tutkitaan kelirikon vaikutuksia liiketoimintaan erityisesti caseyksikössä, joka on metsäteollisuusyhtiön Venäjällä sijaitseva tuotantoyksikkö. Venäläinen liiketoimintaympäristö eroaa huomattavasti suomalaisesta, ja kelirikon aikana korostuvat etenkin korruption ja henkilökohtaisten suhteiden merkitys. Suuri osa havaituista sallitun painon ylityksistä hoidetaan kelirikon aikana maksamalla epävirallisia maksuja suoraan tarkastajille. Myös virallisia kulkulupia myydään, mutta niiden hankinta on kallista ja aikaa vievää. Työn lähtökohta kiteytyy lainsäädännön, viranomaisten tulkinnan ja todellisen tilanteen välisten ristiriitojen avaamiseen ja selvittämiseen, ja tavoitteena on ollut mahdollisimman objektiivisen kokonaiskuvan luominen tilanteesta. Case-yksikössä on kehitetty vaihtoehtoisia toimintamalleja kelirikkoajan kuljetusten varmistamiseksi. Rautatiekuljetusten määrää on lisätty huomattavasti ja välivarastointiterminaalin rakentamista on suunniteltu. Vaihtoehtoiset toimintamallit aiheuttavat kuitenkin huomattavia lisäkustannuksia. Tutkimuksen tuottamien tietojen avulla case-yhtiössä voidaan jatkossa arvioida todellisia riskejä sekä vaihtoehtoisten toimintamallien tarpeellisuutta ja kustannustehokkuutta aikaisempaa tarkemmin.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A model to estimate damage caused by gray leaf spot of corn (Cercospora zea-maydis) was developed from experimental field data gathered during the summer seasons of 2000/01 and during the second crop season [January-seedtime] of 2001, in the southwest of Goiás state. Three corn hybrids were grown over two seasons and on two sites, resulting in 12 experimental plots. A disease intensity gradient (lesions per leaf) was generated through application, three times over the season, of five different doses of the fungicide propiconazol. From tasseling onward, disease intensity on the ear leaf (El), and El - 1, El - 2, El + 1, and El + 2, was evaluated weekly. A manual harvest at the physiological ripening stage was followed by grain drying and cleaning. Finally, grain yield in kg.ha-1 was estimated. Regression analysis, performed between grain yield and all combinations of the number of lesions on each leaf type, generated thirty linear equations representing the damage function. To estimate losses caused by different disease intensities at different corn growth stages, these models should first be validated. Damage coefficients may be used in determining the economic damage threshold.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ostotapahtumassa kiinnitetään usein huomiota hintaan, mutta hankintapäätökseen vaikuttavat myös muutkin kustannukset. Ongelman asiassa aiheuttaa kokonaiskustannusvaikutuksien arvioinnin ja mittauksen haasteellisuus, sekä kunnollisen raportointijärjestelmän puuttuminen. Hankinnan kokonaiskustannusten selvittäminen pitkällä aikavälillä on kuitenkin tärkeää, koska hankintojen osuus yritysten liikevaihdoista on jatkuvassa kasvussa. Työn tarkoituksena oli tarkastella Total cost of ownershipia, eli TCO:ta, elinkaarilaskennan sovellusta. Tarkastelun aluksi työlle luotiin teoreettinen pohja käyttäen hyväksi kirjallisuutta, artikkeleita sekä www-dokumentteja. Teoriaosuus rakentui kustannuslaskennan osalta kustannusten tunnistamisesta, jakamisesta ja kohdistamisesta. TCO:sta luotiin mahdollisimman laaja-alainen teoreettinen kuvaus. Seuraavaksi työssä käsiteltiin TCO:n soveltamista sen perinteisimpiin käyttökohteisiin: taloudellisesti merkittäviin hankintoihin, ulkoistamispäätöksiin, hinnoitteluun sekä toimittajien suorituskyvyn seurantaan ja analysointiin. TCO:n soveltamista käsittelevä osuus päätettiin kotimaisilla esimerkeillä TCO:n soveltamisesta IT-hankintojen apuvälineenä. Työ päätettiin käymällä läpi työtä tehdessä kypsyneet ajatukset sekä johtopäätökset.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Diplomityö tehtiin Lappeenrannan teknillisen yliopiston konetekniikan laitokselle. Diplomityö on osa teknillisen yliopiston biomekaanista tutkimusta, jonka tarkoituksena on mallintaa ihmisen tuki- ja liikuntaelimistön toimintaa. Työssä pyrittiin selvittämään, voitaisiinko sääriluuhun kohdistetun mekaanisen herätteen aiheuttamaa värähtelyvastetta analysoimalla saada tietoa luun ominaistaajuuksista ja lujuudesta. Tietoa voitaisiin käyttää esimerkiksi ostoporoosiriskin arvioinnissa sekä ihmiskehon osien toimintaa kuvaavien simulointimallien verifioinnissa. Mittauslaitteistona käytettiin Brüel & Kjær-moodianalyysilaitteistoa. Laitteistokokonaisuuteen kuuluivat herätevasara, elektromagneettinen täristin, voima-anturi, kaksi kiihtyvyysmitta-anturia sekä PulseLab 2.0 –ohjelmistolla varustettu PC-laitteisto. Tulosten jatkoanalyysi suoritettiin MathWorks yhtiön MatLab v 4.0 -ohjelmistolla. Työssä esitellyn mittaustavan ja -laitteiston todettiin soveltuvan sääriluun värähtelyvasteen mittaamiseen. Mittaustulokset eri mittauskertojen välillä samalla henkilöllä ovat yhtenevät. Tutkimuksen tulosten perusteella ei voida osoittaa luun värähtelyvasteen ja lujuuden välistä suoraa korrelaatiota.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A company’s capability to map out its cost position compared to other market players is important for competitive decision making. One aspect of cost position is direct product cost that illustrates the cost efficiency of a company’s product designs. If a company can evaluate and compare its own and other market players’ direct product costs, it can implement better decisions in product development and management, manufacturing, sourcing, etc. The main objective of this thesis was to develop a cost evaluation process for competitors’ products. This objective includes a process description and an analysis tool for cost evaluations. Additionally, process implementation is discussed as well. The main result of this thesis was a process description consisting of a sixteen steps process and an Excel based analysis tool. Since literature was quite limited in this field, the solution proposal was combined from many different theoretical concepts. It includes influences from reverse engineering, product cost assessment, benchmarking and cost based decision making. This solution proposal will lead to more systematic and standardized cost position analyses and result in better cost transparency in decision making.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resistance induction through the use of chemical inducers often results in physiological costs to the plant. In this study, induced resistance in cotton plants was evaluated with regard to physiological costs in a cultivar susceptible to Colletotrichum gossypii var. cephalosporioides (CNPA GO 2002 - 7997). Plants were cultivated in substrates with two levels of nitrogen and received two applications of acibenzolar-S-methyl (ASM), jasmonic acid (JA) and Agro-Mos® (AM) disease resistance inducers. Plant height (H), internodal length (IL), shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW) and root dry weight (RDW) were evaluated. The activity of the phenylalanine ammonia lyase (PAL) and peroxidase (POX) was also determined. The plants treated with ASM presented high physiological costs with an accentuated reduction in H, SFW and SDW, whereas those treated with JA exhibited a significant increase in SDW, and did not significantly differ from H and IL. In the potting mix supplemented with nitrogen, all inducers differed from the control treatment regarding to internodal length, whereas only ASM and AM presented a significant difference between one another in the potting mix without the addition of nitrogen. Significant correlations (P=0.05) were found for most of the variables analyzed, with greater correlations observed between SFW and SDW (0.94); IL and H (0.74); SFW and H (0.70); and SDW and H (0.70). ASM induced the least amount of PAL activity, significantly differing from the remaining treatments. Greater POX activity was observed in ASM, which significantly differed from the control. AM and JA, however, presented lower activity than the control with regard to these enzymes, and it was not possible to confirm induction resistance in these two treatments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Forest inventories are used to estimate forest characteristics and the condition of forest for many different applications: operational tree logging for forest industry, forest health state estimation, carbon balance estimation, land-cover and land use analysis in order to avoid forest degradation etc. Recent inventory methods are strongly based on remote sensing data combined with field sample measurements, which are used to define estimates covering the whole area of interest. Remote sensing data from satellites, aerial photographs or aerial laser scannings are used, depending on the scale of inventory. To be applicable in operational use, forest inventory methods need to be easily adjusted to local conditions of the study area at hand. All the data handling and parameter tuning should be objective and automated as much as possible. The methods also need to be robust when applied to different forest types. Since there generally are no extensive direct physical models connecting the remote sensing data from different sources to the forest parameters that are estimated, mathematical estimation models are of "black-box" type, connecting the independent auxiliary data to dependent response data with linear or nonlinear arbitrary models. To avoid redundant complexity and over-fitting of the model, which is based on up to hundreds of possibly collinear variables extracted from the auxiliary data, variable selection is needed. To connect the auxiliary data to the inventory parameters that are estimated, field work must be performed. In larger study areas with dense forests, field work is expensive, and should therefore be minimized. To get cost-efficient inventories, field work could partly be replaced with information from formerly measured sites, databases. The work in this thesis is devoted to the development of automated, adaptive computation methods for aerial forest inventory. The mathematical model parameter definition steps are automated, and the cost-efficiency is improved by setting up a procedure that utilizes databases in the estimation of new area characteristics.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bakgrunden och inspirationen till föreliggande studie är tidigare forskning i tillämpningar på randidentifiering i metallindustrin. Effektiv randidentifiering möjliggör mindre säkerhetsmarginaler och längre serviceintervall för apparaturen i industriella högtemperaturprocesser, utan ökad risk för materielhaverier. I idealfallet vore en metod för randidentifiering baserad på uppföljning av någon indirekt variabel som kan mätas rutinmässigt eller till en ringa kostnad. En dylik variabel för smältugnar är temperaturen i olika positioner i väggen. Denna kan utnyttjas som insignal till en randidentifieringsmetod för att övervaka ugnens väggtjocklek. Vi ger en bakgrund och motivering till valet av den geometriskt endimensionella dynamiska modellen för randidentifiering, som diskuteras i arbetets senare del, framom en flerdimensionell geometrisk beskrivning. I de aktuella industriella tillämpningarna är dynamiken samt fördelarna med en enkel modellstruktur viktigare än exakt geometrisk beskrivning. Lösningsmetoder för den s.k. sidledes värmeledningsekvationen har många saker gemensamt med randidentifiering. Därför studerar vi egenskaper hos lösningarna till denna ekvation, inverkan av mätfel och något som brukar kallas förorening av mätbrus, regularisering och allmännare följder av icke-välställdheten hos sidledes värmeledningsekvationen. Vi studerar en uppsättning av tre olika metoder för randidentifiering, av vilka de två första är utvecklade från en strikt matematisk och den tredje från en mera tillämpad utgångspunkt. Metoderna har olika egenskaper med specifika fördelar och nackdelar. De rent matematiskt baserade metoderna karakteriseras av god noggrannhet och låg numerisk kostnad, dock till priset av låg flexibilitet i formuleringen av den modellbeskrivande partiella differentialekvationen. Den tredje, mera tillämpade, metoden kännetecknas av en sämre noggrannhet förorsakad av en högre grad av icke-välställdhet hos den mera flexibla modellen. För denna gjordes även en ansats till feluppskattning, som senare kunde observeras överensstämma med praktiska beräkningar med metoden. Studien kan anses vara en god startpunkt och matematisk bas för utveckling av industriella tillämpningar av randidentifiering, speciellt mot hantering av olinjära och diskontinuerliga materialegenskaper och plötsliga förändringar orsakade av “nedfallande” väggmaterial. Med de behandlade metoderna förefaller det möjligt att uppnå en robust, snabb och tillräckligt noggrann metod av begränsad komplexitet för randidentifiering.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Työssä käytiin läpi Porvoon jalostamon haihtuvien orgaanisten yhdisteiden päästömääritysmenetelmiä ja arvioitiin nykyisin käytössä olevien sekä uusien menetelmien soveltuvuutta Porvoon jalostamon päästömääritykseen. Nykyisten menetelmien arviointia tehtiin käymällä läpi eri alueiden 2000-luvun päästömäärät sekä vertaamalla päästömääriä muiden jalostamojen vastaaviin päästömääriin. Haihtuvista orgaanisista yhdisteistä puhuttaessa jätetään yleisesti metaani määritelmän ulkopuolelle ja käytetään termiä NMVOC-yhdisteet. Työssä laskettiin arvio Porvoon jalostamon metaanin päästömäärälle ja arvioitiin sen vaikutusta NMVOC-kokonaispäästömäärään. Metaanin kokonaispäästömäärien havaittiin olevan noin kymmenen kertaa haihtuvien orgaanisten yhdisteiden päästömääriä pienempiä, ja näin ollen niiden lisäämisellä NMVOC-päästöihin ei ole juuri vaikutusta. Myös menetelmien investointi- ja käyttökustannuksia, sekä pidemmän aikavälin kustannuksia arvioitiin. Kustannuksiltaan tällä hetkellä Porvoon jalostamolla käytössä olevat menetelmät ovat kustannustehokkaita. Uusista menetelmistä DIAL, SOF ja OGI ovat kustannuksiltaan huomattavasti kalliimpia, myös pitkän aikavälin vertailulla. Nykyisten menetelmien vuosittaiset kustannukset aiheutuvat mittausten vaatimista henkilötyötunneista. Uusista menetelmistä SOF ja DIAL vaativat ulkopuolisten mittaajien käyttämistä. Massavirran määrityksen suhteen vielä kehitysvaiheessa olevalla OGI-kameralla mitatessa voidaan käyttää mittaajina omaa henkilökuntaa. Toisin kuin DIAL- ja SOF-menetelmien laitteistot, OGI-kamera ostetaan omaksi ja näin ollen sitä voidaan käyttää tarpeen vaatiessa vuoden ympäri esimerkiksi suurien vuotajien paikallistamiseen ja LDAR-kiristysohjelman tukena. Tarkastelun perusteella olisi suositeltavaa tarkastaa nykyisin käytettävistä laskentamenetelmistä erityisesti prosessi- ja säiliöalueen sekä jätevesijärjestelmä päästömäärät käyttäen tarkempia DIAL-, SOF- tai myöhemmin OGI-menetelmiä ja muokata laskentamenetelmiä vastamaan näillä määritettyjä päästömääriä.