"It has neither name nor place. I shall repeat the reason why I was describing it to you: from the number of imaginable cities we must exclude those whose elements are assembled without a connecting thread, an inner rule, a perspective, a discourse. With cities, it is as with dreams: everything imaginable can be dreamed, but even the most unexpected dream is a rebus that conceals a desire or its reverse, a fear. Cities, like dreams are made of desires and fears, even the thread of their discourse is secret, their rules are absurd, their perspectives deceitful, and everything conceals something else." "Cities also believe they are the work of the mind or of chance, but neither the one nor the other suffices to hold up their walls. You take delight not in a city's seven or seventy wonders, but in the answer it gives to a question of yours." / Master of Architecture

Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: During the last 30 years I have been involved in the theory and practice of thermal engineering and in particular, in the areas of air-cooled heat exchangers and cooling towers for the power, refrigeration, process and petrochemical industries in South Africa and internationally. During this period, I have authored and co-authored more than 120 papers that were published in technical journals or presented at conferences nationally or internationally. Most of these papers are included in a manuscript entitled "Air-cooled Heat Exchangers and Cooling Towers", in which Ipresent a systematic approach to the thermal performance evaluation and design of industrial air-cooled heat exchangers and cooling towers. This original publication also includes the relevant practice applicable to the design of cooling systems, based on my experience as a consultant to industry. Design offices throughout the world presently follow our design methods, or at least employ many of our research results. Our work has furthermore contributed to the development of improved cooling system designs (e.g. new dephlegmator header designs), components (e.g. single-row flattened finned tubes) and product improvement and quality control (e.g. performance testing and measurement of thermal contact resistance between fin and tube during production). Many of our research findings have found application in the modification of existing cooling systems. The manuscript has also been used as reference work during the presentation of short courses to practising engineers and consultants in industry and to engineering graduates at the University of Stellenbosch. A two-volume edition of this manuscript was published by PennWell Corp., Tulsa, Oklahoma, USA in 2004. / AFRIKAANSE OPSOMMING: Gedurende die laaste 30 jaar was ek betrokke by die teorie en praktyk van lugverkoelde warmteoordraers en koeltorings vir die kragopwekkings-, verkoelings-, proses- en petro-chemiesenywerhede in Suid-Afrika sowel as in die buiteland. Gedurende hierdie periode was ek outeur en mede-outeur van meer as 120 publikasies wat in tegniese tydskrifte, of by plaaslike of oorsese konferensies aangebied is. Die meeste van hierdie publikasies vorm deel van 'n manuskrip getiteld "Air-cooled Heat Exchangers and Cooling Towers" waarin ek 'n sistematiese benadering tot die bepaling van die termiese vermoë en ontwerp van industriële lugverkoelde warmteoordraers en koeltorings aanbied. Hierdie oorspronklike publikasie bevat ook die relevante praktyk wat van toepassing is op verkoelingsaanlegte. Ontwerpkantore wêreldwyd volg tans hierdie ontwerpsmetodes, of gebruik ten minste baie van ons navorsingsresultate. Ons werk het verder bygedra tot die ontwikkeling van verbeterde verkoelingsaanlegte (bv. nuwe deflegmatore), komponente (bv. enkelbuisry platvinbuise ) en verbeterde produkte en kwaliteitskontrole (bv. toetsing van verkoelingsvermoë oftermiese kontakweerstand tussen vin en buis gedurende produksie). Baie van ons bevindinge het toepassing gevind in die modifikasie van verkoelingsaanlegte. Die manuskrip is ook as verwysing gebruik gedurende die aanbieding van kort kursusse aan ingenieurs in die praktyk en aan nagraadse studente aan die Universiteit van Stellenbosch. 'n Twee-volume uitgawe van die manuskrip is deur PennWell Corp., Tulsa, Oklahome, VSA in 2004 gepubliseer.

"The purpose of this study was to collect and analyze locational data on all branch maufacturing plants established in Dallas County in 1954, 1955, and 1956; these data were acquired through personal interviews in 1957. For comparative purposes the same data on branch plants established in 1959 were obtained in 1960. The following elements of the locational process were determined and analyzed: 1. Origin and character of the new plants; specifically location of home office, types of products, size and location of the plant in Dallas. 2.locational process, including company personnel assigned the task of locating a suitable site and local agencies assisting in the locational process. 3. reasons for establishing the branch plant 4. factors that influenced management to locate the plant inDallas in preference to any other locations."-- leaf 4.

A técnica de PCR, utilizando-se \"primers\" desenhados a partir do gene que codifica uma proteína imunogênica de 31 KDa de Brucella abortus, foi empregada na detecção de Brucella spp. em 300 amostras de produtos lácteos clandestinos apreendidas em municípios dos Estados de São Paulo (SP) e de Minas Gerais (MG). Foram analisadas 49 amostras de queijo minas frescal e 18 de queijo meia-cura provenientes de MG, e 92 amostras de queijo minas frescal, 33 amostras de queijo meia-cura e 108 amostras de leite cru provenientes de SP. O isolamento bacteriano foi tomado como referência, porém não se isolou Brucella spp. de nenhuma das amostras cujos cultivos mostraram-se contaminados com outros gêneros bacterianos. Pela PCR foi observado que 37 amostras de queijo foram positivas: 29/141 (20,56 %) das amostras de queijo minas frescal e 8/51 (15,68%) das amostras de queijo meia-cura. Todas as amostras positivas na PCR para Brucella spp. foram confirmadas como sendo da espécie Brucella abortus pela técnica de PCR utilizando-se \"primers\" espécie-específicos. Foi instituída a reação de hemi-nested PCR para a diferenciação da cepa em B19 ou campo tomando-se como base a deleção genética de 702 pb existente na cepa vacinal B19. A padronização da técnica permitiu que todas as cepas de Brucella spp. fossem diferenciadas, revelando que 30 (81,08%) amostras eram B19 e 7 (18,92%) eram cepas de Brucella abortus de campo. A concordância estimada entre as técnicas de PCR e do cultivo microbiológico através do indicador Kappa foi considerada baixa (K = 0) devido ao não isolamento do microrganismo. / A PCR assay using primers designed based on the gene that encodes a 31 KDa immunogenic protein from Brucella abortus was used in the detection of Brucella spp. in 300 samples of illegal dairy products obtained in cities of the states of São Paulo (SP) and Minas Gerais (MG), Brazil. A total of 49 samples of minas frescal cheese and 18 samples of meia-cura cheese from MG were analyzed, besides 92 samples of minas frescal cheese, 33 samples of meia-cura cheese and 108 samples of raw milk from SP. Although bacterial isolation was used as reference, Brucella spp. was not isolated from any samples in which culture was contaminated by other genera of bacteria. PCR showed that 37 samples were positive for Brucella spp.: 29/141 (20,56 %) of the minas frescal cheese samples and 8/51 (15,68%) of the meia-cura cheese samples. All positive samples for Brucella spp. were confirmed as Brucella abortus by PCR using species-specific primers. Hemi-nested PCR was used for the differentiation between B19 and field strains, based on the genetic deletion of 702 pb in the vaccinal strain. Standardization of the technique enabled the differentiation of all Brucella spp. strains, showing that 30 of them (81,08%) were B19 and 7 (18,92%) of them were Brucella abortus field strains. Estimated agreement between PCR and microbiological culture as determined by Kappa indicator was considered to be poor (K = 0) due to the absence of isolation of the microorganism.

The submitted doctoral thesis focuses on the development and transformation of the Czechoslovak pencil industry in the period after the onset of the planned economy. The major pencil manufacturer Koh-I-Noor Hardtmuth was at the heart of the analysis. The annual reports, annual financial statements, business trip reports, and minutes of the director's and production meetings formed the source base. The correspondence with individual domestic institutions or foreign business partners, memories and a company magazine were also used. The preserved image archival documents - promotional leaflets and price lists - were not left out. The work is based on the methodological basis of the business history. The organization, operation and management strategies of the pencil industry in the historical background of economic changes and reforms have become the subject to examination. The national enterprises Centropen, Gama and Logarex, which were engaged in the production of office supplies, were also included into the research in terms of the comparison. The emphasis was placed on the role of individual managers conducting entrusted enterprises next to the analysis of turnover, production level and a number of employees. Advertising and promotional activities and their importance in the socialist economy was not left behind. In this context, the impact of extensive litigation regarding the trade mark and the name of Hardtmuth, which affected the export, production and advertising sectors, have not been overlooked. The interrelationship between the manufacturing enterprise and export organizations became one of the key topics.

Applications of the existing steady-state plant-wide optimization and the single-scale fast-rate dynamic optimization strategies to an integrated plant with material recycle have been impeded by several factors. While the steady-state optimization formulation is very simple, the very long transient dynamics of an integrated plant have limited the optimizers execution rate to be extremely low, yielding a suboptimal performance. In contrast, performing dynamic plant-wide optimization at the same rate as local controllers requires exorbitant on-line computational load and may increase the sensitivity to high-frequency dynamics that are irrelevant to the plant-level interactions, which are slow-scale in nature. This thesis proposes a novel multi-scale dynamic optimization and control strategy suitable for an integrated plant. The dynamic plant-wide optimizer in this framework executes at a slow rate to track the slow-scale plant-wide interactions and economics, while leaving the local controllers to handle fast changes related to the local units. Moreover, this slow execution rate demands less computational and modeling requirement than the fast-rate optimizer. An important issue of this method is obtaining a suitable dynamic model when first-principles are unavailable. The difficulties in the system identification process are designing proper input signal to excite this ill-conditioned system and handling the lack of slow-scale dynamic data when the plant experiment cannot be conducted for a long time compared to the settling time. This work presents a grey-box modeling method to incorporate steady-state information to improve the model prediction accuracy. A case study of an integrated plant example is presented to address limitations of the nonlinear model predictive control (NMPC) in terms of the on-line computation and its inability to handle stochastic uncertainties. Then, the approximate dynamic programming (ADP) framework is investigated. This method computes an optimal operating policy under uncertainties off-line. Then, the on-line multi-stage optimization can be transformed into a single-stage problem, thus reducing the real-time computational effort drastically. However, the existing ADP framework is not suitable for an integrated plant with high dimensional state and action space. In this study, we combine several techniques with ADP to apply nonlinear optimal control to the integrated plant example and show its efficacy over NMPC.

Network theory has been widely and successfully used to model, analyse and visualise complex systems. This study aimed to develop approaches to analyse complex integrated sugarcane supply and processing systems. A literature review includes network theory, complex systems, the Theory of constraints, indicator analysis and root cause analysis. The cause-and-effect networks of four sugarcane milling areas in South Africa; viz. Eston, Felixton, Komati and Umfolozi were developed, where the factors that negatively affected the performance of the milling areas were represented by vertices, the relationships among the factors by arcs and the strength of these relationships by weights. Three network theory based analytical tools namely; (a) primary influence vertex analysis, (b) indicator vertex analysis and (c) root cause vertex analysis were developed to analyse the networks. The results from the analyses indicate variations in the numbers and strengths of primary influence factors, problem indicator factors and root causes of problems between the four milling areas. Rainfall, drought and high soil content in sugarcane were identified as the strongest primary influences in the respective milling areas. High crush rate variability, low cutter productivity, running behind allocation and increases in operating costs were identified as the strongest indicators of poor performance in the respective milling areas. Rainfall was found to be the most dominating root cause of poor performance in all the milling areas. Since the South African integrated sugarcane production and processing system is complex, it is likely that the unique approaches developed in this study can be used successfully to also analyse other relatively complex systems. It is recommended that these approaches be tested within other systems. The main contribution of this study is in the form of a relatively easy-to-use network theory based comprehensive systems analyses tool. This analytical approach has, to the author's knowledge, not been used in any agri-industrial application previously. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

The co-owned Umfolozi Mill area has developed as an integrated supply chain. Cane supply reliability was identified as a potential area for productivity improvement at Umfolozi. It is important that the cane supply to a sugar mill arrives at a steady and reliable rate. A reliable cane supply ensures that the mill can operate at an optimum efficiency. Sugarcane supply reliability depends on how the mill area adapts to unforeseeable changes in the supply chain. An important aspect to this is the weather and how it affects the harvesting regimes. The sugarcane supply chain at Umfolozi is divided into two branches, road transport and tram transport. The trams account for 70 % of the cane delivered to the mill and the can is sourced from a climatically homogenous region. In the occurrence of a rainfall event of above 5 mm, infield harvesting cannot take place on the Umfolozi Flats; hence 70 % of the mill‟s supply is halted for one or more days. To address the problem, a stochastic model was created to simulate the effectiveness of an enlarged cane stockpile if it were maintained on the current tram sidings outside the mill and were crushed when wet weather prevented further harvesting. The stockpile was simulated on a first-in first-out principle and was able to supply the mill with enough cane to continue running for 24 hours. The model was then used to conduct a series of Monte Carlo simulations on which sensitivity analyses and economic feasibility assessments were carried out. Results show that the stockpile was effective in reducing the length of milling season and the number of no-cane stops. However, on further analysis into the implications of creating a stockpile it was found that 1% recoverable value (RV) was lost during the 24-hours that the cane is stored outside the mill. The loss in revenue as a result of the RV reduction had a negative impact on any savings created with the implementation of the stockpile. This result made apparent the negative impact of deterioration to the whole supply chain. Further research is required to determine more accurately the rate of deterioration, and therefore, quantify more accurately the losses that occur in the supply chain. A significant outcome of the study was the development of a mechanistic tool which drove decision making at Umfolozi Sugar Mill. It lead to the development of the modelling framework LOMZI, a simulations based framework which places more emphasis on environmental factors and risks. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

In this thesis, it is shown how aflatoxins can be determined in biological material. The thesis is a summary of five papers. Aflatoxins are carcinogenic mycotoxins produced by Aspergillus moulds. Methods were developed for the determination of aflatoxins in samples of airborne dust and human urine collected at feed factories. For the dust samples from such agricultural products as copra, cotton seed and maize, methods were developed for the determination of aflatoxins B1, B2, G1 and G2. For urine samples, methods were developed for analysing the four aflatoxins above that naturally occur in dust, and the metabolites aflatoxins M1 and Q1. Sample preparation of dust samples included solvent extraction, filtration and immunoaffinity column extraction. Urine samples were cleaned up using immunoaffinity column extraction or solid-phase extraction using ethyl bonded-phase columns. All extractions with these columns were automated by means of a laboratory robot. Reversed-phase liquid chromatography was used to separate the aflatoxins in the cleaned-up extracts. Detection was performed by fluorescence after post-column derivatization by addition of bromine. Parameters for the derivatization were studied using factorial designs. To confirm the identity of aflatoxins in naturally contaminated airborne dust samples and spiked urine, liquid chromatography was combined with electrospray mass spectrometry. The detection limits of the aflatoxins in dust samples were in the range 1.8-3.1 ng/g in 10-mg dust samples using fluorescence detection. Aflatoxins were determined in spiked urine down to the 6.8-18 pg/ml level. In naturally contaminated dust of copra and cotton seed, aflatoxins were detected with a content of 9-50 pg/mg of aflatoxin Bi. No aflatoxins could be detected in any urine sample obtained from feed factory workers that were less than 6.8 pg/ml of aflatoxins B1, B2, G1 and G2 and less than 18 pg/ml of aflatoxins M1 and Q1. / <p>Diss. (sammanfattning) Umeå : Univ., härtill 5 uppsatser</p> / digitalisering@umu

The importance of automating the garment manufacturing process has been understood since the early 1980s. However, in spite of millions of dollars spent on research, three decades later, the industry is still far from achieving a fully autonomous process. Previous work on fabric control in automated sewing focused on the control of only a single sheet of fabric using an industrial manipulator with an overhead vision system. These methods did not meet the accuracy and robustness requirements of the sewing process with respect to fabric position and fabric tension. To address these issues, a new method for fabric control in automated sewing is described. It uses the current feed mechanism on sewing machines, feed dogs, but modifies them to be servo-controlled. These servo controlled actuators, servo dogs, individually control two sheets of fabric before the fabric reaches the needle and during the sewing process. The servo dogs actuate the fabric 180o out of phase with the sewing needle, providing incremental control of the fabric when the needle is out of the fabric. To achieve this type of control successfully for automated sewing, the servo dogs have been designed for short displacement, high acceleration motions using a cable drive system powered by voice coil motors. Feedback of fabric position has been determined to be necessary and is to be provided by a thread-tracking vision system. This thesis outlines the general design of the system and discusses a prototype used to validate the design, and describes experiments performed to examine how the fabric will behave with the use of this type of actuation method.