Estudo de Eletrodeposição de Ligas Cu-Sn em Meio de Citrato de Sódio

Revestimentos produzidos a partir de ligas de Cu-Sn apresentam grande interesse em função de suas propriedades, originando uma grande capacidade de aplicação industrial, especialmente em indústrias de componentes e materiais eletrônicos. Tais ligas também têm sido comercialmente utilizadas como revestimentos em metais diferentes, como o aço, para protegê-los contra a corrosão e melhorar sua aparência. Na presente dissertação, técnicas de voltametria cíclica, cronoamperometria e voltametria de varredura anódica linear foram utilizadas para o estudo dos processos de deposição de Cu e/ou Sn a partir de dois conjuntos de soluções contendo CuCl2.2H2O e SnCl2.2H2O nas razões de Cu:Sn = 1:10 e 10:1, além de Na3C6H5O7 1,00 mol/L, em pH = 6,0. As curvas de voltametria cíclica realizadas sobre o eletrodo de grafita foram utilizadas para o cálculo das constantes de equilíbrio dos complexos de ambos os metais com citrato de sódio, bem como na determinação dos potenciais catódicos aplicados nos ensaios de cronoamperometria. Após a deposição da liga nos potenciais estipulados para cada uma das duas soluções, os revestimentos de liga Cu-Sn foram ressolubilizados em solução de NaNO3 0,5 mol/L, empregando varredura anódica linear para a avaliação de suas composições químicas. Os resultados iniciais mostraram que a variação da concentração de Cu (II) e do potencial aplicado influenciaram no teor de cobre na liga. Contudo, percebeu-se que o teor de estanho não sofreu grandes variações, independente das concentrações das soluções e do potencial aplicado. Na solução com maior concentração de cobre foram alcançados teores dos metais na liga em maior proximidade com o da liga de bronze comercial. Com base nesses resultados, foram produzidos revestimentos de ligas sobre substrato de aço carbono, a partir de soluções contendo CuCl2.2H2O e SnCl2.2H2O na razão de 10:1, empregando a técnica de cronoamperometria potenciostática. Quatro diferentes valores de potencial (-0,39V, -0,67V, -1,00V, -1,20V e -1,94V vs. Ag/AgClsat.) foram aplicados, obtendo-se camadas cujas colorações variaram do rosa claro ao marrom escuro, sempre sem brilho. A eficiência de corrente catódica (Ef) decresceu conforme o potencial aplicado se tornou mais negativo. Nesta mesma direção, verificou-se um aumento do teor de estanho na liga depositada e menores tamanhos de grão. Porém, quando o potencial tornou-se mais negativo (-1,20V e -1,94V), observou-se a presença de cristalitos de diferentes tamanhos e de dendritos. Revestimentos com melhores resistências à corrosão em solução de NaCl 0,5 mol/L foram produzidos nos potenciais de -1,00V e -1,20V, cujas composições foram 99,40 % m/m Cu / 0,60 % m/m Sn e 97,70 % m/m Cu / 2,30 % m/m Sn, respectivamente. As análises por DRX permitiram verificar que estes revestimentos eram constituídos, principalmente, da fase α-CuSn

Wear of hardfacing white cast irons by solid particle erosion

The response of three commercial weld-hardfacing alloys to erosive wear has been studied. These were high chromium white cast irons, deposited by an open-arc welding process, widely used in the mineral processing and steelmaking industries for wear protection. Erosion tests were carried out with quartz sand, silicon carbide grit and blast furnace sinter of two different sizes, at a velocity of 40 m s-1 and at impact angles in the range 20° to 90°. A monolithic white cast iron and mild steel were also tested for comparison. Little differences were found in the wear rates when silica sand or silicon carbide grit was used as the erodent. Significant differences were found, however, in the rankings of the materials. Susceptibility to fracture of the carbide particles in the white cast irons played an important role in the behaviour of the white cast irons. Sinter particles were unable to cause gross fracture of the carbides and so those materials with a high volume fraction of carbides showed the greatest resistance to erosive wear. Silica and silicon carbide were capable of causing fracture of the primary carbides. Concentration of plastic strain in the matrix then led to a high wear rate for the matrix. At normal impact with silica or silicon carbide erodents mild steel showed a greater resistance to erosive wear than these alloys. © 1995.

Micromachining of glassy carbon toolsets for micro embossing applications

Laser micro machining is fast gaining popularity as a method of fabricating micro scale structures. Lasers have been utilised for micro structuring of metals, ceramics and glass composites and with advances in material science, new materials are being developed for micro/nano products used in medical, optical, and chemical industries. Due to its favourable strength to weight ratio and extreme resistance to chemical attack, glassy carbon is a new material that offers many unique properties for micro devices. The laser machining of SIGRADUR® G grade glassy carbon was characterised using a 1065 nm wavelength Ytterbium doped pulsed fiber laser. The laser system has a selection of 25 preset waveforms with optimised peak powers for different pulsing frequencies. The optics provide spot diameter of 40 μm at the focus. The effect of fluence, transverse overlap and pulsing frequency (as waveform) on glassy carbon was investigated. Depth of removal and surface roughness were measured as machining quality indicators. The damage threshold fluence was determined to be 0.29 J/cm2 using a pulsing frequency of 250 kHz and a pulse width of 18 ns (waveform 3). Ablation rates of 17 < V < 300 μm3/pulse were observed within a fluence range of 0.98 < F < 2.98 J/cm2. For the same fluence variation, 0.6 μm to 6.8 μm deep trenches were machined. Trench widths varied from 29 μm at lower fluence to 47 μm at the higher fluence. Square pockets, 1 mm wide, were machined to understand the surface machining or milling. The depth of removal using both waveform 3 and 5 showed positive correlation with fluence, with waveform 5 causing more removal than waveform 3 for the same fluence. Machined depths varied from less than 1 μm to nearly 40 μm. For transverse overlap variation using waveform 3, the best surface finish with Rz = 1.1 μm was obtained for fluence 0.792 J/cm2 for transverse overlap of 1 μm, 6 μm, and 9 μm at machined depths of 22.9 μm, 6.6 μm, and 4.6 μm respectively. For fluence of 1.426 J/cm2, the best surface finish with Rz = 1.2 μm was obtained for transverse overlap of 6 μm, and 9 μm at machined depths of 12.46 μm, and 8.6 μm respectively. The experimental data was compiled as machining charts and utilised for fabricating a micro-embossing glassy carbon master toolsets as a capability demonstration.

Effects of the biodiesel fuel physical properties on the swirl stabilised spray combustion characteristics

An increasin g interest in biofuel applications in modern engines requires a better understanding of biodiesel combustion behaviour. Many numerical studies have been carried out on unsteady combustion of biodiesel in situations similar to diesel engines, but very few studies have been done on the steady combustion of biodiesel in situations similar to a gas turbine combustor environment. The study of biodiesel spray combustion in gas turbine applications is of special interest due to the possible use of biodiesel in the power generation and aviation industries. In modelling spray combustion, an accurate representation of the physical properties of the fuel is a first important step, since spray formation is largely influenced by fuel properties such as viscosity, density, surface tension and vapour pressure. In the present work, a calculated biodiesel properties database based on the measured composition of Fatty Acid Methyl Esters (FAME) has been implemented in a multi-dimensional Computational Fluid Dynamics (CFD) spray simulation code. Simulations of non-reacting and reacting atmospheric-pressure sprays of both diesel and biodiesel have been carried out using a spray burner configuration for which experimental data is available. A pre-defined droplet size probability density function (pdf) has been implemented together with droplet dynamics based on phase Doppler anemometry (PDA) measurements in the near-nozzle region. The gas phase boundary condition for the reacting spray cases is similar to that of the experiment which employs a plain air-blast atomiser and a straight-vane axial swirler for flame stabilisation. A reaction mechanism for heptane has been used to represent the chemistry for both diesel and biodiesel. Simulated flame heights, spray characteristics and gas phase velocities have been found to compare well with the experimental results. In the reacting spray cases, biodiesel shows a smaller mean droplet size compared to that of diesel at a constant fuel mass flow rate. A lack of sensitivity towards different fuel properties has been observed based on the non-reacting spray simulations, which indicates a need for improved models of secondary breakup. By comparing the results of the non-reacting and reacting spray simulations, an improvement in the complexity of the physical modelling is achieved which is necessary in the understanding of the complex physical processes involved in spray combustion simulation. Copyright © 2012 SAE International.

超声与磁粉强化含单宁废水生物处理研究

单宁是一种典型的有毒难降解污染物，在制革、造纸、制药、印染等行业废水中广泛存在，对水环境造成污染并且影响废水生物处理效果。本研究针对含单宁废水生物处理效率低、较高浓度时微生物受抑制且污泥容易膨胀等问题，采用超声和磁粉来强化含单宁废水生物处理，研究超声和磁粉对微生物活性、污染物去除及污泥沉降性能的影响，并对其作用机理进行了分析和探讨。 研究结果表明，活性污泥系统中单宁酸容积负荷可以达到1.8kgCOD/(m3·d)，单宁酸和COD去除率分别达到85.2%和79.6%，但如果负荷进一步增大则微生物活性迅速降低。系统在pH 5~8、温度20~35℃、DO>1 mg/L的条件下具有较好的单宁酸降解效果和处理稳定性。单宁降解动力学参数为：μmax =0.208h-1；Ks=226mg/L；Ki=522mg/L；kd=0.0092h-1；Y =0.594。 磁粉对系统处理效果和污泥沉降性能有一定的促进作用，且效果要优于外磁场。适宜的磁粉粒径和投加量分别为0.05~0.15mm和1.0g/L，COD去除率比对照系统提高6.4%，SVI降低28.6%，污泥絮体结构紧密。磁粉强化主要是通过其对污泥菌胶团的凝聚、吸附作用以及对微生物活性的强化作用实现。 在适当强度（0.4W/cm2）和辐照时间（20min）的超声作用下污泥絮体和细胞膜通透性增大，酶分泌也增多，系统的COD去除率比对照提高了8.8%，单宁酶酶活提高了11%。但超声也使污泥絮体结构松散，沉降性能下降，SVI比对照系统升高9.3%。 由于污泥流失加剧导致污泥浓度相对较低，声磁联合强化系统相对于磁粉强化系统其处理效果并没有提高。但相对于单纯活性污泥系统，声磁联合作用下系统处理效果、污泥沉降性能以及系统运行稳定性都得到明显改善。本研究为难降解废水的生物处理提供了一个新的思路。 Tannins are typical refractory and toxic pollutants that commonly exist in wastewater from dye, medicine, paper and leather industries and cause many problems associated with environmental pollution and biological treatment of wastewater. Biological treatment efficiency of tannin-containing wastewater is usually low owing to its biological toxicity and low biodegradability, microbes are usually inhibited under high tannin concentration and sludge bulking frequently occurs. In this study, ultrasound and magnetic powder were used to improve the biological treatment performance of simulated tannic acid-containing wastewater. The effects of ultrasonic irradiation and magnetic powder on microbial activity, tannic acid degradation rate and sludge sedimentation were investigated. The augmentation mechanisms were analyzed and discussed. The experimental results showed that the microbes were prominently inhibited under high tannic acid concentration, but moderate degradation efficiency can be maintained under a tannic acid load of up to 1.8kgCOD/(m3·d), with the tannic acid degradation and COD removal percentage of 85.2% and 79.6% respectively. The highest degradation rates and treatment stability were achieved at pH range of 5~8, temperature range of 20~35℃ and DO concentration of above 1mg/L. The kinetic parameters were estimated, including: μmax =0.208h-1；Ks=226mg/L；Ki=522mg/L；kd=0.0092h-1；Y =0.594. The microbial activity, tannic acid degradation rate and sludge sedimentation were improved by adding Fe3O4 magnetic powder, and the augmentation performance was better than external magnetic field. The appropriate particle size and dosage of magnetic powder were found to be 0.05~0.15mm and 1.0g/L, respectively, under which the COD removal percentage was improved by 6.4% and SVI value decreased by 28.6%, and compact floc structure was observed. This was mainly caused by the flocculation and adsorption effects of magnetic powder against sludge floc and the stimulation of microbial activity under appropriate magnetic field. Under appropriate ultrasonic irradiation (ultrasonic intensity 0.4W/cm2, ultrasonic irradiation time 20min), the permeability of floc and cell membrane are improved, transfer of substrate and oxygen were reinforced; meanwhile, more enzyme were produced by microbes under the slight damage caused by ultrasound. However, the floc structure became loose under ultrasonic irradiation, leading to relatively poor sedimentation, with the SVI value 9.3% higher than the control system. Although the magnetic powder-ultrasonic irradiation combined augmentation system showed no improvement in treatment performance compared with sole magnetic augmentation system owing to its relatively low sludge concentration, it guaranteed the stable operation of system, meanwhile the tannic acid degradation and sludge sedimentation were significantly improved compared with sole activated sludge system. This study gives a new idea for biological treatment of refractory wastewater.

Numerical simulation of coil-helix transition processes of gelatin

Gelatin is widely used in food, pharmaceutical, and photographic industries due to the coil-helix transition, whereas the structural inhomogeneity considerably affects its essential properties closely connecting with the industrial applications. The spatially structural inhomogeneity of the gelatin caused by the uneven and unstable temperature field is analyzed by the finite element method during the cooling-induced coil-helix transition process. The helix conversion and the crosslinking density as functions of time and spatial grid are calculated by the incremental method. A length distribution density function is introduced to describe the continuous length distributions of two kinds of triple helices.

Biosynthesis of fluorescent allophycocyanin alpha-subunits by autocatalysis in Escherichia coli

APC (allophycocyanin) is widely used for fluorescence tagging and may be a promising antioxidant agent for use within the food and pharmaceutical industries. Chromophore attachment to apo-ApcA (apo-APC alpha-subunit without chromophore) can be auto-catalysed both in vitro and in vivo. In the present study, a plasmid containing genes of apo-ApcA and chromophore synthetases (HOI (ferredoxin-dependent haem oxygenase) and PcyA (phycocyanobilin:ferredoxin oxidoreductase)] was constructed and expressed in Escherichia coli. The results show that holo-ApcA (APC alpha-subunit with chromophore) can be synthesized by autocatalysis in E. coli. Recombinant holo-ApcA showed the same spectral and fluorescent properties as PC (phycocyanin) and could serve as a good substitute for native PC for fluorescent tagging. Moreover, recombinant ApcA can inhibit hydroxyl and peroxyl radicals more strongly than holo-ApcA and native APC. The EC50 values were 296.4 +/- 22.4 mu g/ml against hydroxyl radicals and 38.5 +/- 2.6 mu g/ml against peroxyl radicals.

In vitro determination of antioxidant activity of proteins from jellyfish Rhopilema esculentum

In this study, the antioxidant activity of proteins isolated from jellyfish, Rhopilema esculentum Kishinouye (R. esculentum), was determined by various antioxidant assays, including superoxide anion radical-scavenging, hydroxyl radical-scavenging, total antioxidant activity, reducing power and metal chelating activity. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol, vitamin C and mannitol were used as standards in those various antioxidant activities. The crude protein (CP) and the protein fractions isolated by Sephadex chromatography, first peak (FP) and second peak (SP), had very low reductive power and metal chelating abilities compared to EDTA, but they showed strong scavenging effects on the superoxide anion radical, hydroxyl radical and varying total antioxidant activity. FP and SP exhibited stronger scavenging effects on the superoxide anion radical than BHA, BHT or a-tocopherol. The EC50 values of FP and SP were 6.12 and 0.88 mu g/ml, respectively, while values EC50 of BHA, BHT and alpha-tocopherol were 31, 61 and 88 mu g/ml, respectively. CP, FP and SP showed far higher hydroxyl radical-scavenging activities than did vitamin C or mannitol. The EC50 values of CP, FP and SP were 48.76, 45.42 and 1.52 mu g/ml, but EC50 values of vitamin C and mannitol were 1907 and 4536 mu g/ml, respectively. In a beta-carotene-linoleate system, SP and CP showed antioxidant activity, but lower than BHA. Of the three samples, SP had the strongest antioxidant activity. So, SP may have a use as a possible supplement in the food and pharmaceutical industries. (c) 2005 Elsevier Ltd. All rights reserved.

Radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum

In this study, radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum (R. esculentum) was assayed including superoxide anion radical and hydroxyl radical scavenging. The protein samples showed strong scavenging activity on superoxide anion radical and values EC50 of full protein (FP), first fraction (IFF), second fraction (SF), and 30% (NH4)(2)SO4 precipitate (Fr-1) were 2.65, 7.28, 1.10, and 22.51 mu g/mL, respectively, while values EC50 of BHA, BHT, and alpha-tocopherol were 31, 6 1, and 88 pg/mL, respectively. Also, the protein samples had strong scavenging effect on hydroxyl radical and the values EC50 of FP, FF, SF, Fr-1, and Fr-2 were 48.91, 27.72, 1.82, 16.36, and 160.93 mu g/mL, but values EC50 of Vc and mannitol were 1907 and 4536 mu g/mL, respectively. Of the five protein samples, SF had the strongest radical scavenging activity and may have a use as a possible supplement in the food and pharmaceutical industries. The radical scavenging activity was stable at high temperature so that R. esculentum may be used as a kind of natural functional food. (c) 2005 Elsevier Ltd. All rights reserved.

连续生产过程CIMS的研究

比较了连续生产过程与离散生产过程的不同特点,提出了适合连续生产过程CIMS的体系结构.并从参考模型,开发工具和集成平台等三个方面探讨了实现CIMS如何走工程化和产业化道路的问题。

两种超微细矿物粉体材料的制备及应用研究

Superfine mineral materials are mainly resulted from the pulverization of natural mineral resources, and are a type of new materials that can replace traditional materials and enjoy the most extensive application and the highest degree of consumption in the present day market. As a result, superfine mineral materials have a very broad and promising prospect in terms of market potential. Superfine pulverization technology is the only way for the in-depth processing of most of the traditional materials, and is also one of the major means for which mineral materials can realize their application. China is rich in natural resources such as heavy calcite, kaolin, wollastonite, etc., which enjoy a very wide market of application in paper making, rubber, plastics, painting, coating, medicine, environment-friendly recycle paper and fine chemical industries, for example. However, because the processing of these resources is generally at the low level, economic benefit and scale for the processing of these resources have not been realized to their full potential even up to now. Big difference in product indices and superfine processing equipment and technologies between China and advanced western countries still exists. Based on resource assessment and market potential analysis, an in-depth study was carried out in this paper about the superfine pulverization technology and superfine pulverized mineral materials from the point of mineralogical features, determination of processing technologies, analytical methods and applications, by utilizing a variety of modern analytical methods in mineralogy, superfine pulverization technology, macromolecular chemistry, material science and physical chemistry together with computer technology and so on. The focus was placed on the innovative study about the in-depth processing technology and the processing apparatus for kaolin and heavy calcite as well as the application of superfine products. The main contents and the major achievements of this study are listed as follows: 1. Superfine pulverization processing of mineral materials shall be integrated with the study of their crystal structures and chemical composition. And special attention shall be put on the post-processing technologies, rather than on the indices for particle size, of these materials, based on their fields of application. Both technical feasibility and economic feasibility shall be taken into account for the study about superfine pulverization technologies, since these two kinds of feasibilities serve as the premise for the industrialized application of superfine pulverized mineral materials. Based on this principle, preposed chemical treatment method, technology of synchronized superfine pulverization and gradation, processing technology and apparatus of integrated modification and depolymerization were utilized in this study, and narrow distribution in terms of particle size, good dispersibility, good application effects, low consumption as well as high effectiveness of superfine products were achieved in this study. Heavy calcite and kaolin are two kinds of superfine mineral materials that enjoy the highest consumption in the industry. Heavy calcite is mainly applied in paper making, coating and plastics industries, the hard kaolin in northern China is mainly used in macromolecular materials and chemical industries, while the soft kaolin in southern China is mainly used for paper making. On the other hand, superfine pulverized heavy calcite and kaolin can both be used as the functional additives to cement, a kind of material that enjoys the biggest consumption in the world. A variety of analytical methods and instruments such as transmission and scanning electron microscopy, X-ray diffraction analysis, infrared analysis, laser particle size analysis and so on were applied for the elucidation of the properties and the mechanisms for the functions of superfine mineral materials as used in plastics and high-performance cement. Detection of superfine mineral materials is closely related to the post-processing and application of these materials. Traditional detection and analytical methods for superfine mineral materials include optical microscopy, infrared spectral analysis and a series of microbeam techniques such as transmission and scanning electron microscopy, X-ray diffraction analysis, and so on. In addition to these traditional methods, super-weak luminescent photon detection technology of high precision, high sensitivity and high signal to noise ratio was also utilized by the author for the first time in the study of superfine mineral materials, in an attempt to explore a completely new method and means for the study of the characterization of superfine materials. The experimental results are really exciting! The innovation of this study is represented in the following aspects: 1. In this study, preposed chemical treatment method, technology of synchronized superfine pulverization and gradation, processing technology and apparatus of integrated modification and depolymerization were utilized in an innovative way, and narrow distribution in terms of particle size, good dispersibility, good application effects, low consumption as well as high effectiveness of superfine products were achieved in the industrialized production process*. Moreover, a new modification technology and related directions for producing the chemicals were invented, and the modification technology was even awarded a patent. 2. The detection technology of super-weak luminescent photon of high precision, high sensitivity and high signal to noise ratio was utilized for the first time in this study to explore the superfine mineral materials, and the experimental results can be compared with those acquired with scanning electron microscopy and has demonstrated its unique advantages. It can be expected that further study may possibly help to result in a completely new method and means for the characterization of superfine materials. 3. During the heating of kaolinite and its decomposition into pianlinite, the diffraction peaks disappear gradually. First comes the disappearance of the reflection of the basal plane (001), and then comes the slow disappearance of the (hkl) diffraction peaks. And this was first discovered during the experiments by the author, and it has never before reported by other scholars. 4. The first discovery of the functions that superfine mineral materials can be used as dispersants in plastics, and the first discovery of the comprehensive functions that superfine mineral materials can also be used as activators, water-reducing agents and aggregates in high-performance cement were made in this study, together with a detailed discussion. This study was jointly supported by two key grants from Guangdong Province for Scientific and Technological Research in the 10th Five-year Plan Period (1,200,000 yuan for Preparation technology, apparatus and post-processing research by using sub-micron superfine pulverization machinery method, and 300,000 yuan for Method and instruments for biological photon technology in the characterization of nanometer materials), and two grants from Guangdong Province for 100 projects for scientific and technological innovation (700,000 yuan for Pilot experimentation of superfine and modified heavy calcite used in paper-making, rubber and plastics industry, and 400,000 yuan for Study of superfine, modified wollastonite of large length-to-diameter ratio).

动漫行业创业者胜任特征研究

Venture has become an important force for the sustainable economic growth of China, However, research on entrepreneurs is far failed to meet the actual needs, Animation and Comic Industry is an important component of the state-led Cultural and Creative Industries. Entrepreneurship is the rapid growth of population, but the empirical research on the Animation and Comic Industry entrepreneurs’ Competent Characteristic Model is rarely heard. As a manager of a national incubator which major in Cultural and Creative Industry, study these entrepreneurs competent characteristics is my responsibility. As an exploration, the study uses Competent Characteristic Model of classical design methods and behavior events interview method, and selects entrepreneurs which of animation and comic industry business start-up period as the objects. Through coding analysis of 31 entrepreneurs’ interview information, completed the amendment to the dictionary coding, and ultimately construct the animation and comic industry entrepreneurs need to have the threshold competence model and differentiating competence model. Differentiating competence model includes six competencies: tolerance and optimism, cooperation, creative innovation, pool talents, vision, decision-making and tempo control. Threshold competence model includes twenty features, divided into three dimensions: personal characteristics, knowledge quality, capacity of the quality. Knowledge and capacity of the quality are closely related to the core work of entrepreneurs, Personal characteristics concern the deep-seated motivation of the entrepreneurs. The study also analyses and discusses the characteristics of the entrepreneurs on the demographic variables.

Engineering design of a bioprocess for the production of natural red colourants by submerged fermentation of the thermophilic fungus Penicillium purpurogenum GH2

The development of a new bioprocess requires several steps from initial concept to a practical and feasible application. Industrial applications of fungal pigments will depend on: (i) safety of consumption, (ii) stability of the pigments to the food processing conditions required by the products where they will be incorporated and (iii) high production yields so that production costs are reasonable. Of these requirements the first involves the highest research costs and the practical application of this type of processes may face several hurdles until final regulatory approval as a new food ingredient. Therefore, before going through expensive research to have them accepted as new products, the process potential should be assessed early on, and this brings forward pigment stability studies and process optimisation goals. Only ingredients that are usable in economically feasible conditions should progress to regulatory approval. This thesis covers these two aspects, stability and process optimisation, for a potential new ingredient; natural red colour, produced by microbial fermentation. The main goal was to design, optimise and scale-up the production process of red pigments by Penicillium purpurogenum GH2. The approach followed to reach this objective was first to establish that pigments produced by Penicillium purpurogenum GH2 are sufficiently stable under different processing conditions (thermal and non-thermal) that can be found in food and textile industries. Once defined that pigments were stable enough, the work progressed towards process optimisation, aiming for the highest productivity using submerged fermentation as production culture. Optimum production conditions defined at flask scale were used to scale up the pigment production process to a pilot reactor scale. Finally, the potential applications of the pigments were assessed. Based on this sequence of specific targets, the thesis was structured in six parts, containing a total of nine chapters. Engineering design of a bioprocess for the production of natural red colourants by submerged fermentation of the thermophilic fungus Penicillium purpurogenum GH2.

The numerical modelling of multi-physics phenomena: The shape casting process

In this paper a computer simulation tool capable of modelling multi-physics processes in complex geometry has been developed and applied to the casting process. The quest for high-quality complex casting components demanded by the aerospace and automobile industries, requires more precise numerical modelling techniques and one that need to be generic and modular in its approach to modelling multi-processes problems. For such a computer model to be successful in shape casting, the complete casting process needs to be addressed, the major events being:-• Filling of hot liquid metal into a cavity mould • Solidification and latent heat evolution of liquid metal • Convection currents generated in liquid metal by thermal gradients • Deformation of cast and stress development in solidified metal • Macroscopic porosity formation The above phenomena combines the analysis of fluid flow, heat transfer, change of phase and thermal stress development. None of these events can be treated in isolation as they inexorably interact with each other in a complex way. Also conditions such as design of running system, location of feeders and chills, moulding materials and types of boundary conditions can all affect on the final cast quality and must be appropriately represented in the model.

Safer by design: using computer simulation to predict the evacuation performance of passenger ships

When designing a new passenger ship or modifiying an existing design, how do we ensure that the proposed design is safe from an evacuation point of view? In the building and aviation industries, computer based evacuation models are being used to tackle similar issues. In these industries, the traditonal restrictive prescriptive approach to design is making way for performance based design methodologies using risk assessment and computer simulation. In the maritime industry, ship evacuation models off the promise to quickly and efficiently bring these considerations into the design phase, while the ship is "on the drawing board". This paper describes the development of evacuation models with applications to passenger ships and further discusses issues concerning data requirements and validation.