A comprehensive dual-scale wood torrefaction model : application to the analysis of thermal run-away in industrial heat treatment processes

A dual-scale model of the torrefaction of wood was developed and used to study industrial configurations. At the local scale, the computational code solves the coupled heat and mass transfer and the thermal degradation mechanisms of the wood components. At the global scale, the two-way coupling between the boards and the stack channels is treated as an integral component of the process. This model is used to investigate the effect of the stack configuration on the heat treatment of the boards. The simulations highlight that the exothermic reactions occurring in each single board can be accumulated along the stack. This phenomenon may result in a dramatic eterogeneity of the process and poses a serious risk of thermal runaway, which is often observed in industrial plants. The model is used to explain how thermal runaway can be lowered by increasing the airflow velocity, the sticker thickness or by gas flow reversal.

Investigations Into the Significance of Lysine Residues in IGF-I

This PhD thesis presents novel and original research in the field of Insulin-like Growth Factor-I (or IGF-I) biology. IGF-I plays an essential role in promoting normal human growth and development; it also represents both a target and treatment for various diseases. This thesis provides interesting insights into previously uncharacterised mechanisms of action that underlie IGF-I biology. Such findings may lead to improved and novel treatments across a broad range of medical conditions.

Lysine residues of IGF-I are substrates for transglutaminases and modulate downstream IGF-I signalling

Numerous studies have reported associations between IGF-I and other extra cellular matrix (ECM) proteins, including fibronectin (FN), integrins, IGF-binding proteins (IGFBPs) and through IGFBPs, with vitronectin (VN). Nevertheless, the precise nature and mechanisms of these interactions are still being characterised. In this paper, we discuss transglutaminases (TGases) as a constituent of the ECM and provide evidence for the first time that IGF-I is a lysine (K)-donor substrate to TGases. When IGF-I was incubated with an alpha-2 plasmin inhibitor-derived Q peptide in the presence of tissue transglutaminase (TG2), an IGF-I:Q peptide cross-linked species was detected using Western immunoblotting and confirmed by mass spectrometry. Similar findings were observed in the presence of Factor XIIIa (FXIIIa) TGase. To identify the precise location of this K-donor TGase site/s on IGF-I, all the three IGF-I K-sites, individually and collectively (K27, K65 and K68), were substituted to arginine (R) using site-directed mutagenesis. Incubation of these K→R IGF-I analogues with Q peptide in the presence of TG2 or FXIIIa resulted in the absence of cross-linking in IGF-I analogues bearing arginine substitution at site 68. This established that K68 within the IGF-I D-domain was the principal K-donor site to TGases. We further annotated the functional significance of these K→R IGF-I analogues on IGF-I mediated actions. IGF-I analogues with K→R substitution within the D-domain at K65 and K68 hindered migration of MCF-7 breast carcinoma cells and correspondingly reduced PI3-K/AKT activation. Therefore, this study also provides first insights into a possible functional role of the previously uncharacterised IGF-I D-domain.

PEGylation of lysine residues reduces the pro-migratory activity of IGF-I

Background: The insulin-like growth factor (IGF) system is composed of ligands and receptors which regulate cell proliferation, survival, differentiation and migration. Some functions are regulated via intracellular signaling cascades, others by involvement of the extracellular milieu, including binding proteins and other extracellular matrix proteins. However, understanding of their functions and the exact nature of these interactions remains incomplete. Methods: IGF-I was PEGylated at its lysine sites - K27, K65 and K68. Binding of PEG-IGF-I to the IGFBPs was analyzed using BIAcore and its ability to activate the IGF-IR was assessed using IGF-IR phosphorylation assay. Furthermore, functional consequences of PEGylating the lysine residues of IGF-I was investigated using cell viability and cell migration assays. In addition, particular downstream signaling pathways regularly implicated in these mechanisms were also dissected using phospho-AKT and phospho-ERK1/2 assays. Results: In this study, IGF-I specifically PEGylated at lysine 27 (PEG-K27), 65 (PEG-K65) or 68 (PEG-K68) were employed. Receptor phosphorylation was only reduced by 2-fold with PEG-K65 and PEG-K68 over all the time points tested, and as observed in two cell types, 3T3 fibroblasts and MCF-7 breast cancer cells. PEGylation at K27 resulted in a much larger effect, with more than 10-fold lower activation for 3T3 fibroblasts and a ~3 fold reduced IGF-IR activation for MCF-7 breast cancer cells over 15 minutes. In addition, all PEG-IGF-I variants demonstrated a ten-fold reduction in the association rate to IGF binding proteins (IGFBPs). Functionally, all PEG variants completely lost their ability to induce cell migration in the presence of IGFBP-3/vitronectin (VN) complexes as compared to IGF-I; in contrast, cell viability was fully preserved. Further investigations into the downstream signaling pathways revealed that the PI3-K/AKT pathway was preferentially affected upon treatment with the PEG-IGF-I variants compared to the MAPK/ERK pathway. Conclusion: PEGylation of IGF-I has an impact on cell migration but not cell viability. General significance: PEG-IGF-I may differentially modulate IGF-I mediated functions that are dependent on its interaction with its receptor as well as key extracellular proteins such as VN and IGFBPs.

Industrial land price and its impact on urban growth : a Chinese case study

China is experiencing rapid progress in industrialization, with its own rationale toward industrial land development based on a deliberate change from an extensive to intensive form of urban land use. One result has been concerted attempts by local government to attract foreign investment by a low industrial land price strategy, which has resulted in a disproportionally large amount of industrial land within the total urban land use structure at the expense of the urban sprawl of many cities. This paper first examines “Comparable Benchmark Price as Residential land use” (CBPR) as the theoretical basis of the low industrial land price phenomenon. Empirical findings are presented from a case study based on data from Jinyun County, China. These data are analyzed to reveal the rationale of industrial land price from 2000 to 2010 concerning the CBPR model. We then explore the causes of low industrial land prices in the form of a “Centipede Game Model”, involving two neighborhood regions as “major players” to make a set of moves (or strategies). When one of the players unilaterally reduces the land price to attract investment with the aim to maximize profits arising from the revenues generated from foreign investment and land premiums, a two-player price war begins in the form of a dynamic game, the effect of which is to produce a downward spiral of prices. In this context, the paradox of maximizing profits for each of the two players are not accomplished due to the inter-regional competition of attracted investment leading to a lose-lose situation for both sides’ in competing for land premium revenues. A short-term solution to the problem is offered involving the establishment of inter-regional cooperative partnerships. For the longer term, however, a comprehensive reform of the local financial system, more adroit regional planning and an improved means of evaluating government performance is needed to ensure the government's role in securing pubic goods is not abandoned in favor of one solely concerned with revenue generation.

High frequency high power converters for industrial applications

The main contribution of this project was to investigate power electronics technology in designing and developing high frequency high power converters for industrial applications. Therefore, the research was conducted at two levels; first at system level which mainly encapsulated the circuit topology and control scheme and second at application level which involves with real-world applications. Pursuing these objectives, varied topologies have been developed and proposed within this research. The main aim was to resolving solid-state switches limited power rating and operating speed while increasing the system flexibility considering the application characteristics. The developed new power converter configurations were applied to pulsed power and high power ultrasound applications for experimental validation.

Purification of particles of subterranean clover red leaf virus using an industrial-grade cellulase

Particles of two isolates of subterranean clover red leaf virus were purified by a method in which infected plant tissue was digested with an industrial-grade cellulase, Celluclast® 2.0 L type X. The yields of virus particles using this enzyme were comparable with those obtained using either of two laboratory-grade cellulases, Cellulase type 1 (Sigma) and Driselase®. However, the specific infectivity or aphid transmissibility of the particles purified using Celluclast® was 10-100 times greater than those of preparations obtained using laboratory-grade cellulases or no enzyme. The main advantage of using Celluclast® is that at present in Australia its cost is only ca. 1% of laboratory-grade cellulases.

Provotypes: Teasing out tensions between industrial context and use context

What industrial organisations think people do and what they actually do are often two very different things. But exactly this tension can be a source of innovation: how can we give form to insights about what people do, to deliberately challenge industries' conceptions, and inspire new product and service development

Ethnography of software maintenance activities in an industrial engineering setup

New technical and procedural interventions are less likely to be adopted in industry, unless they are smoothly integrated into the existing practices of professionals. In this paper, we provide a case study of the use of ethnographic methods for studying software bug-fixing activities at an industrial engineering conglomerate. We aimed at getting an in-depth understanding of software developers' everyday practices in bug-fixing related projects and in turn inform the design of novel productivity tools. The use of ethnography has allowed us to look at the social side of software maintenance practices. In this paper, we highlight: 1) organizational issues that influence bug-fixing activities; 2) social role of bug tracking systems, and; 3) social issues specific to different phases of bug-fixing activities.

Numerical investigation of mechanical and thermal dynamic properties of the industrial transformer

Industrial transformer is one of the most critical assets in the power and heavy industry. Failures of transformers can cause enormous losses. The poor joints of the electrical circuit on transformers can cause overheating and results in stress concentration on the structure which is the major cause of catastrophic failure. Few researches have been focused on the mechanical properties of industrial transformers under overheating thermal conditions. In this paper, both mechanical and thermal properties of industrial transformers are jointly investigated using Finite Element Analysis (FEA). Dynamic response analysis is conducted on a modified transformer FEA model, and the computational results are compared with experimental results from literature to validate this simulation model. Based on the FEA model, thermal stress is calculated under different temperature conditions. These analysis results can provide insights to the understanding of the failure of transformers due to overheating, therefore are significant to assess winding fault, especially to the manufacturing and maintenance of large transformers.

A gene encoding a new cold-active lipase from an Antarctic isolate of Penicillium expansum

Cold-active lipases are of significant interest as biocatalysts in industrial processes. We have identified a lipase that displayed activity towards long carbon-chain-p-nitrophenyl substrates (C12–C18) at 25 °C from the culture supernatant of an Antarctic Penicillium expansum strain assigned P. expansum SM3. Zymography revealed a protein band of around 30 kDa with activity towards olive oil. DNA fragments of a lipase gene designated as lipPE were isolated from the genomic DNA of P. expansum SM3 by genomic walking PCR. Subsequently, the complete genomic lipPE gene was amplified using gene-specific primers designed from the 5′- and 3′-regions. Reverse transcription PCR was used to amplify the lipPE cDNA. The deduced amino acid sequence consisted of 285 residues that included a predicted signal peptide. Three peptides identified by LC/MS/MS analysis of the proteins in the culture supernatant of P. expansum were also present in the deduced amino acid sequence of the lipPE gene suggesting that this gene encoded the lipase identified by initial zymogram activity analysis. Full analysis of the nucleotide and the deduced amino acid sequences indicated that the lipPE gene encodes a novel P. expansum lipase. The lipPE gene was expressed in E. coli for further characterization of the enzyme with a view of assessing its suitability for industrial applications.

Minimization of bauxite residue neutralization products using nanofiltered seawater

Currently, open circuit Bayer refineries pump seawater directly into their operations to neutralize the caustic fraction of the Bayer residue. The resulting supernatant has a reduced pH and is pumped back to the marine environment. This investigation has assessed modified seawater sources generated from nanofiltration processes to compare their relative capacities to neutralize bauxite residues. An assessment of the chemical stability of the neutralization products, neutralization efficiency, discharge water quality, bauxite residue composition, and associated economic benefits have been considered to determine the most preferable seawater filtration process based on implementation costs, savings to operations and environmental benefits. The mechanism of neutralization for each technology was determined to be predominately due to the formation of Bayer hydrotalcite and calcium carbonate, however variations in neutralization capacity and efficiencies have been observed. The neutralization efficiency of each feed source has been found to be dependent on the concentration of magnesium, aluminium, calcium and carbonate. Nanofiltered seawater with approximately double the amount of magnesium and calcium required half the volume of seawater to achieve the same degree of neutralization. These studies have revealed that multiple neutralization steps occur throughout the process using characterization techniques such as X-ray diffraction (XRD), infrared (IR) spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES).

Effective routing with utilisation of cross-layer information for industrial wireless sensor networks

This thesis focuses on providing reliable data transmissions in large-scale industrial wireless sensor networks through improving network layer protocols. It addresses three major problems: scalability, dynamic industrial environments and coexistence of multiple types of data traffic in a network. Theoretical developments are conducted, followed by simulation studies for verification of theoretic results. The approach proposed in this thesis has been shown to be effective for large-scale network implementation and to provide improved data transmission reliability for both periodic and sporadic traffic.

Mechanisms of mono- and poly-ubiquitination : ubiquitination specificity depends on compatibility between the E2 catalytic core and amino acid residues proximal to the lysine

Ubiquitination involves the attachment of ubiquitin to lysine residues on substrate proteins or itself, which can result in protein monoubiquitination or polyubiquitination. Ubiquitin attachment to different lysine residues can generate diverse substrate-ubiquitin structures, targeting proteins to different fates. The mechanisms of lysine selection are not well understood. Ubiquitination by the largest group of E3 ligases, the RING-family E3 s, is catalyzed through co-operation between the non-catalytic ubiquitin-ligase (E3) and the ubiquitin-conjugating enzyme (E2), where the RING E3 binds the substrate and the E2 catalyzes ubiquitin transfer. Previous studies suggest that ubiquitination sites are selected by E3-mediated positioning of the lysine toward the E2 active site. Ultimately, at a catalytic level, ubiquitination of lysine residues within the substrate or ubiquitin occurs by nucleophilic attack of the lysine residue on the thioester bond linking the E2 catalytic cysteine to ubiquitin. One of the best studied RING E3/ E2 complexes is the Skp1/Cul1/F box protein complex, SCFCdc4, and its cognate E2, Cdc34, which target the CDK inhibitor Sic1 for K48-linked polyubiquitination, leading to its proteasomal degradation. Our recent studies of this model system demonstrated that residues surrounding Sic1 lysines or lysine 48 in ubiquitin are critical for ubiquitination. This sequence-dependence is linked to evolutionarily conserved key residues in the catalytic region of Cdc34 and can determine if Sic1 is mono- or poly-ubiquitinated. Our studies indicate that amino acid determinants in the Cdc34 catalytic region and their compatibility to those surrounding acceptor lysine residues play important roles in lysine selection. This may represent a general mechanism in directing the mode of ubiquitination in E2 s.

A study of the effects metal residues in poly(9,9-dioctylfluorene) have on field-effect transistor device characteristics

The amount of metal residues from organometallic reagents used in preparation of poly(9,9-dioctylfluorene) by palladium catalysed Suzuki and nickel-induced Yamamoto polycondensations have been determined, and their effect upon the behaviour of the polymer in field-effect transistors (FETs) has been measured. The metal levels from material polymerised by Suzuki method were found to be much higher than from that made by the Yamamoto procedure. Simple treatment of the polymers with suitable metal trapping reagents lowered the metal levels significantly, with EDTA giving best results for nickel and triphenylphosphine for palladium. Comparison of the behaviour of FETs using polyfluorenes with varying levels of metal contamination, showed that the metal residues have little effect upon the mobility values, but often affect the degree of hysteresis, possibly acting as charge traps. Satisfactory device performances were obtained from polymer with palladium levels of 2000 μg/g suggesting that complete removal of metal residues may not be necessary for satisfactory device performance.