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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

\"Formação de radialistas na era da inclusão discursiva: uma reflexão sobre a condição comunicativo-educativa do rádio no campo das políticas públicas\" / Education and formation to perform in the long-sought active citizenship: a critical reflection about the possible re-signification on the radio in the field of social empowerment.

Ana Luisa Zaniboni Gomes 01 March 2007 (has links)
Considerando que no Brasil a radiodifusão é um serviço público do Estado executado por terceiros através de autorizações ou concessões, o rádio - reconhecidamente o mais acessível e popular dos meios de comunicação ainda não se percebe e nem é percebido como importante aliado das políticas públicas. Entretanto, ao dar face humana a essas emissoras, verifica-se que muitos radialistas vêm desempenhando um importante papel social e transformador da realidade em seus territórios locais. Dados recolhidos junto a 155 radialistas de 142 emissoras de diferentes naturezas e expressões sobre a formação que buscaram - e ainda buscam - para o exercício de suas atividades cotidianas, permitem uma reflexão crítica acerca da possível ressignificação do veículo a partir da conscientização de seus comunicadores para o papel educativo que ambos têm a desempenhar no almejado protagonismo cidadão. / Considering that in Brazil broadcasting is a State public service performed by third parties through authorizations or concessions, radio broadcast - by far the most accessible and popular media of public communication still does not recognize itself and is not recognized as an important ally of the public politics. However, upon giving human face to those radio stations, it is possible to understand that some radio announcers have developed an important social role, as transformers of the reality in their local areas. Accounts from 155 radio announcers from 142 radio stations with diverse natures and expressions about their circunstances and what kind of formative role they sought - and still seek - for the exercise of its activities, allows a critical reflection about the possible re-signification of the radio in the field of social empowerment, including the possibility of understanding the founding source that Education and formation must perform in the long-sought active citizenship.
192

Enacting the Silence of Subaltern Women : Julie Otsuka and the Japanese Picture Brides

Leonte, Eva January 2017 (has links)
It is by now a truth universally acknowledged that the world’s subaltern women (in Gayatri Spivak’s understanding of the term) cannot make their voices heard, that what we think we know about them are mostly stereotypes of our own making. It is likewise acknowledged that literature has a privileged status when it comes to representing these women, given its unique prerogative to retrieve their traces and convey their subjectivity through imagining. Literary texts which embark on this task can be seen as symbolic speech acts and, as such, they depend upon their illocutionary force for success in the public sphere. In this thesis I have chosen to discuss The Buddha in the Attic by Julie Otsuka (2011) – a novel I perceive as a collective speech act – from the combined perspective of speech-act criticism (J. L. Austin, S. Petrey), subaltern studies (G. Spivak, G. Pandey) and feminist theory (M. P. Lara, S. Lanser). My analysis explores the interrelation between this little-known story of the first-generation Japanese women immigrants to the US and the sophisticated narrative strategy which sustains it, continually balancing between the women's heterogeneity and their shared experiences, especially their systematic silencing by the dominant population. Finally, the thesis discusses the novel’s larger illocutionary implications for the public sphere, in particular how the reclaiming of the past creates new understandings of the present as well as opens up onto the future.               Keywords: Otsuka, The Buddha in the Attic, migrant literature, picture brides, subalternity, feminist theory, communal voice, speech-act criticism, illocutionary force.
193

Institutional dynamics in a small-scale organic farming organisation : the case of the Ezemvelo Farmers' Organisation

Msomi, Thulisile Felicity January 2017 (has links)
Magister Philosophiae (Land and Agrarian Studies) - MPhil(LAS) / This study explores institutional dynamics within an organic farming organisation, the Ezemvelo Farmers' Organisation (EFO), based in uMbumbulu in KwaZulu-Natal (KZN). The main objective of the study was to identify the institutional and governance factors that impact on the sustainability of the organic production programme of the EFO. A variety of research methods were employed, including a small sample survey of 50 households, in-depth interviews with key respondents, and a critical assessment of the existing literature on the EFO. The study established that many rural households in uMbumbulu maintain their livelihoods through a diverse array of activities that include social grants. Agriculture remains an important livelihood strategy for many households. It presents opportunities for income generation, access to food, job creation and increased asset accumulation. Communal land tenure systems do not constrain agricultural development, and kinship ties and social relations determine affordable and flexible land access for farming and residential use. The EFO initiave regenerated agricultural production in uMbumbulu. Many households have rights to cropping fields and these fields were revitalised and put under productive use as the organic farming initiative gained momentum. The EFO marketed its produce to Farmwise, a packhouse that distributes produce to various retailers. The agro-food industry is dominated by large business interests and maintained exploitative relations with the EFO. Organic production and marketing to such businesses imposed high transaction costs on members of the EFO as onerous quality standards were enforced throughout the value chain. Rural development interventions that are driven by external stakeholders such as academic institutions, government departments and other agencies tend not to provide sustainable solutions to help support the development of smallholder farmers. In the case of the EFO, such support saw abuses of power, elite capture, free-rider problems, conflict and weak management systems. The thesis argues that the agrarian transformation imperative means that policy frameworks must be re-examined, and adapted to the needs and local practices of smallholder farmers such as members of the EFO. Proper extension support that provides accurate market information, effective coordination of production and transport services, and relevant infrastructure, is also required. / National Research Foundation (NRF)
194

Operation of Decentralised Wastewater Treatment Systems (DEWATS) under tropical field conditions

Reynaud, Nicolas 09 November 2015 (has links) (PDF)
Decentralised Wastewater Treatment Systems (DEWATS) such as disseminated by the Bremen Overseas Research and Development Association (BORDA) are increasingly being recognized by decision makers across the world as an option for service delivery in densely populated low-income areas. However, little practical experience has been gathered methodologically on basic engineering and performance aspects surrounding these systems. This thesis investigates full-scale anaerobic reactors of communal DEWATS implemented in tropical regions in order to consolidate the basis of future design and support monitoring, operation and maintenance procedures. Special focus is laid on the operation of the Anaerobic Baffled Reactor (ABR) as the core technology of DEWATS. Field research has been conducted for over four years at numerous communal systems in Indonesia, India and South Africa in order to (i) verify the generally used parameter values for DEWATS design and operation, (ii) identify factors limiting the treatment efficiency of existing systems in the field and (iii) investigate the performance of DEWATS and DEWATS treatment steps (especially ABRs) under tropical field conditions in terms of effluent concentration, Chemical Oxygen Demand (COD) removal, sludge stabilisation and sludge activity. Field data on average per capita wastewater production in DEWATS implementation areas, long term fluctuations and peak-flow values are presented. General per capita organic load and per capita nutrient load, per capita biogas production in digesters and per capita sludge accumulation in ABRs are estimated. Based on available data and field observations, treatment limiting factors are hypothesised to be rain-water intrusion, general under-loading, organic under-loading and elevated raw-water salinity in coastal areas. Effluent measurements performed at one hundred nine systems in Indonesia indicated guaranteed maximum concentrations of 200 mg CODt l-1 for anaerobic DEWATS treatment effluent if the treated wastewater is non-saline. ABR COD reduction of four case studies was poor in three cases and fair in one case. Sludge accumulation rates indicated good sludge stabilisation and sludge activity in all four systems. Anaerobic Filters (AF) contributed in all three case studies, in which they were part of the plant design, significantly to COD reduction. Nutrient effluent concentrations were comparably high. Large fractions of effluent organics were found to be biodegradable. It is hypothesised that system treatment would improve significantly if maximum hydraulic load was lower, general organic load was higher and therefore both close to design estimation. It is thus proposed to control the amount of storm water intruding the systems, increase feed concentration through partial grey-water exclusion and reduce the nutrient load in system effluent through partial urine diversion. It is further proposed to reduce the HRT of the settler below 10 h in order to increase the organic load to the ABR. It is further hypothesised that systems could be operated at higher hydraulic dry weather load than currently assumed since active anaerobic digestion appears to be capable of establishing itself under extreme hydraulic pressure. This may lead to a considerable reduction of building costs. Anaerobic digestion modelling with the existing ADM-3P model confirmed that observed sludge accumulation rates indicate active hydrolytic systems. The model could however not be used to produce soluble COD effluent concentration benchmarks due to its sensitivity to methanogenic rate constants. The general view held for anaerobic reactors treating wastewater with high solid content is that hydrolysis is the rate-limiting degradation step. It is hypothesised that this does not apply for solid accumulating systems such as the ABR. / Die durch die Bremen Overseas Research and Development Association (BORDA) verbreiteten Decentralised Wastewater Treatment Systems (DEWATS) werden international von Entscheidungsträgern zunehmend als Möglichkeit angesehen, kommunale Abwasserreinigung in dichtbesiedelten, einkommensschwachen Gegenden zu ermöglichen. Allerdings wurden bislang wenig praktische Erfahrungen methodisch über grundlegende Aspekte der Anlagendimensionierung und Anlagenleistungsfähigkeit aufgenommen. Im Rahmen dieser Dissertation wurden anaerobe Reaktoren kommunaler DEWATS unter tropischen Feldbedingungen untersucht, um eine Datengrundlage für zukünftige Dimensionierung, Wartung und Betrieb, als auch Monitoring der Anlagen zu schaffen. Schwerpunkt wurde dabei auf den Anaerobic Baffled Reactor (ABR) als Kerntechnologie von DEWATS gelegt. Felduntersuchungen wurden in der Zeit von mehr als vier Jahren an zahlreichen kommunalen DEWATS in Indonesien, Indien und Südafrika durchgeführt, um (i) die gängig gewählten Parameterwerte für Anlagen-Dimensionierung und -Betrieb zu überprüfen, (ii) leistungslimitierende Faktoren im Feldbetrieb zu identifizieren und um (iii) die Leistungsfähigkeit von DEWATS und DEWATS-Reinigungsstufen (insbesondere des ABRs) unter tropischen Feldbedingungen bezüglich Abflusskonzentrationen, Reduzierung des Chemischen Sauerstoffbedarfs (CSB), Schlammstabilisierung und Schlammaktivität zu untersuchen. Basierend auf den Untersuchungsergebnissen, wurden durchschnittliche Einwohnergleichwerte, Langzeitvariationen und Faktoren für Zuflussspitzen für kommunale Abwasserproduktion in DEWATS-Zielbevölkerungsgruppen präsentiert. Ferner werden allgemeine Pro-Kopf-CSB-Frachten, -Ammoniumfrachten und -Phosphorfrachten, die Pro-Kopf-Biogasproduktion in kommunalen Biogasanlagen sowie die Pro-Kopf-Schlammakkumulation in ABRs abgeschätzt. Auf Felduntersuchungen basierend, wurden Fremdwassereinfluss, generelle Unterbelastung, organische Unterbelastung und erhöhte Frischwassersalinität in Küstengebieten als leistungslimitierende Faktoren im Feldbetrieb identifiziert. An 109 indonesischen Anlagen durchgeführte Abflusskonzentrationsmessungen ließen auf eine garantierte Abflusskonzentration der anaeroben Reaktoren von 200 mg CSB l-1 schließen, wenn der negative Einfluss von erhöhter Frischwassersalinität ausgeschlossen werden kann. Der CSB-Abbau durch ABRs in vier detailliert untersuchten DEWATS war gering in drei Fällen und befriedigend in einem Fall. Anaerobe Filter (AF) trugen in den drei Fällen, in denen sie Teil der Anlagenkonfigurationen waren, signifikant zur CSB-Reduzierung bei. Ammonium- und Phoshorkonzentrationen in allen Reaktorabläufen waren vergleichsweise hoch. Ein großer Anteil des CSBs in Reaktorabläufen war biologisch abbaubar. Es wird die Hypothese aufgestellt, dass sich die Leistungsfähigkeiten der Anlagen signifikant verbessern würden, wären die Anlagenbelastungen den Auslegungswerten ähnlicher, d.h., wären die maximalen hydraulischen Belastungen geringer und die organischen Belastungen höher. Es wird deshalb geraten, den Fremdwasserzufluss zu minimieren, die Anlagenzulaufkonzentration durch partielle Grauwasserversickerung zu erhöhen und die Ammonium- und Phoshorkonzentration im Zulauf durch partiellen Urinabschlag zu verringern. Es wird außerdem vorgeschlagen, die hydraulische Aufenthaltszeit in Absetzbecken (settlers) auf zehn Stunden zu begrenzen, um so die organische Belastung der ABRs zu erhöhen. Ferner wird die Hypothese aufgestellt, dass Anlagen unter höherer Trockenwetterbelastung als bislang angenommen betrieben werden können, da aktiver anaerober Abbau auch unter extremen hydraulischen Belastungen möglich erscheint. Dies könnte zu einer signifikanten Senkung der Baukosten führen. Die Modellierung anaerober Abbauprozesse mit dem existierenden ADM-3P-Modell bestätigten, dass im Feld beobachtete Schlammakkumulationsraten auf eine aktive Hydrolyse schließen lassen. Das Modell konnte jedoch nicht genutzt werden, um Bezugswerte für den gelösten CSB im Ablauf der Anlagen zu erhalten, da es eine vergleichsweise hohe Sensitivität in Bezug auf die Raten für Methanogenese aufwies. Die allgemein anerkannte Sichtweise ist, dass die Hydrolyse den geschwindigkeitsbestimmenden Abbauschritt bei der anaeroben Behandlung feststoffreicher Abwässer darstellt. Es wird die Hypothese aufgestellt, dass dieses nicht für feststoffakkumulierende Systeme, wie den ABR, zutrifft.
195

La comptabilité de gestion dans les organisations du bloc communal : quelle réalité ? / Managerial accounting in local authorities : An overview of the current/real situation

Letort, Frederique 22 November 2016 (has links)
Quelle comptabilité de gestion pour les organisations du bloc communal ? C’est la question que pose cettethèse. L’objet de cette recherche est d'étudier comment - sous quelle forme et pour répondre à quels objectifs- les communes et les établissements publics de coopération intercommunale (EPCI) utilisent la comptabilitéde gestion. A l'origine, la comptabilité de gestion s'adresse aux entreprises et sa transposition auxorganisations non marchandes, aux finalités différentes, pose question. L’étude de la littérature montre uncheminement chaotique de cet outil du contrôle de gestion dans les organisations du bloc communal depuisles années 1980, avec l’influence d’un certain idéaltype de la comptabilité de gestion émanant des entreprises.La littérature récente ne rend pas compte de la situation actuelle de cet outil dans les organisationscommunales.Une recherche exploratoire de nature qualitative, sur neuf cas, montre une grande diversité des pratiques enmatière de comptabilité de gestion et permet de poser des hypothèses. Celles-ci sont ensuite testées à plusgrande échelle dans le cadre d’une étude quantitative. L’analyse de 124 questionnaires complétés par descadres territoriaux met en évidence une utilisation accrue de la comptabilité de gestion pour répondre à desobjectifs différenciés, ainsi qu’une diversité des approches et des méthodes permettant la construction detypologies. Cette recherche montre que les organisations du bloc communal ont majoritairement opté pourune approche contingente de la comptabilité de gestion. Les logiques de transposition actuelles sontdavantage focalisées sur les finalités de la comptabilité de gestion (la recherche de légitimité ou d’efficience)que sur son contenu (la méthode de calcul de coûts). / This thesis raises the question of the appropriate type of management accounting in local government. Thepurpose of this research is to study how local authorities have been using managerial accounting. Originally,managerial accounting was meant for companies and using it for non-profit organizations, which have differentpurposes, is problematic. Studying the literature on this topic shows that the use of this management tool bylocal authorities since the 1980s has not been smooth, as it originated from an ideal-type of managerialaccounting applying to companies. There is no recent literature reflecting the real conditions of thismanagement tool in local authorities.Our exploratory and qualitative research, built on nine case studies, reveals a wide variety of practices, whichenabled us to develop research hypotheses. These hypotheses were then tested on a large-scale, throughquantitative research. The 124 completed questionnaires we analyzed showed that managerial accounting isincreasingly used to address diversified targets and uses different approaches and methods. This in turnenabled us to build typologies. This research shows that local authorities have opted for a contingent approachto managerial accounting. Current transpositions focus more on the aims of management accounting (lookingfor legitimacy or efficiency), than on its contents (cost method).
196

SOUČASNÁ PRAXE V NAKLÁDÁNÍ S BIOLOGICKY ROZLOŽITELNÝMI ODPADY / CONTEMPORARY PRACTICE IN DISPOSE OF BIODEGRADABLE WASTE

Šmejkalová, Zuzana January 2008 (has links)
This diploma paper deals with contemporary practice in dispose of biodegradable waste, especially biodegradable communal waste (biowaste) in the Czech Republic. It explains fundamental terms, points out relevant legal rules and describes methods of biowaste handling. It evaluates collection and utilization systems in two cities in the way of comparison method. It compares them from cost and benefits (economic, environmental) points of view. The main purpose of the diploma paper is general introduction into the issue, pointing out negative effect of biowaste landfilling and presentation of actual systems of utilization. Also the work points out contemporary trend consisting in raising separation and reducing biodegradable communal waste landfilling.
197

Design lehkého zemědělského traktoru / Design of Light Agricultural Tractor

Oulehla, Jakub January 2019 (has links)
The subject of this diploma is the design of a versatile light agricultural tractor. The design of the tractor will focus on timeless design. The proposed tractor will also differ from the current competition in the field of light agricultural tractors. The resulting tractor will also be usable outside agriculture, in horticulture or communal services.
198

Operation of Decentralised Wastewater Treatment Systems (DEWATS) under tropical field conditions

Reynaud, Nicolas 16 December 2014 (has links)
Decentralised Wastewater Treatment Systems (DEWATS) such as disseminated by the Bremen Overseas Research and Development Association (BORDA) are increasingly being recognized by decision makers across the world as an option for service delivery in densely populated low-income areas. However, little practical experience has been gathered methodologically on basic engineering and performance aspects surrounding these systems. This thesis investigates full-scale anaerobic reactors of communal DEWATS implemented in tropical regions in order to consolidate the basis of future design and support monitoring, operation and maintenance procedures. Special focus is laid on the operation of the Anaerobic Baffled Reactor (ABR) as the core technology of DEWATS. Field research has been conducted for over four years at numerous communal systems in Indonesia, India and South Africa in order to (i) verify the generally used parameter values for DEWATS design and operation, (ii) identify factors limiting the treatment efficiency of existing systems in the field and (iii) investigate the performance of DEWATS and DEWATS treatment steps (especially ABRs) under tropical field conditions in terms of effluent concentration, Chemical Oxygen Demand (COD) removal, sludge stabilisation and sludge activity. Field data on average per capita wastewater production in DEWATS implementation areas, long term fluctuations and peak-flow values are presented. General per capita organic load and per capita nutrient load, per capita biogas production in digesters and per capita sludge accumulation in ABRs are estimated. Based on available data and field observations, treatment limiting factors are hypothesised to be rain-water intrusion, general under-loading, organic under-loading and elevated raw-water salinity in coastal areas. Effluent measurements performed at one hundred nine systems in Indonesia indicated guaranteed maximum concentrations of 200 mg CODt l-1 for anaerobic DEWATS treatment effluent if the treated wastewater is non-saline. ABR COD reduction of four case studies was poor in three cases and fair in one case. Sludge accumulation rates indicated good sludge stabilisation and sludge activity in all four systems. Anaerobic Filters (AF) contributed in all three case studies, in which they were part of the plant design, significantly to COD reduction. Nutrient effluent concentrations were comparably high. Large fractions of effluent organics were found to be biodegradable. It is hypothesised that system treatment would improve significantly if maximum hydraulic load was lower, general organic load was higher and therefore both close to design estimation. It is thus proposed to control the amount of storm water intruding the systems, increase feed concentration through partial grey-water exclusion and reduce the nutrient load in system effluent through partial urine diversion. It is further proposed to reduce the HRT of the settler below 10 h in order to increase the organic load to the ABR. It is further hypothesised that systems could be operated at higher hydraulic dry weather load than currently assumed since active anaerobic digestion appears to be capable of establishing itself under extreme hydraulic pressure. This may lead to a considerable reduction of building costs. Anaerobic digestion modelling with the existing ADM-3P model confirmed that observed sludge accumulation rates indicate active hydrolytic systems. The model could however not be used to produce soluble COD effluent concentration benchmarks due to its sensitivity to methanogenic rate constants. The general view held for anaerobic reactors treating wastewater with high solid content is that hydrolysis is the rate-limiting degradation step. It is hypothesised that this does not apply for solid accumulating systems such as the ABR. / Die durch die Bremen Overseas Research and Development Association (BORDA) verbreiteten Decentralised Wastewater Treatment Systems (DEWATS) werden international von Entscheidungsträgern zunehmend als Möglichkeit angesehen, kommunale Abwasserreinigung in dichtbesiedelten, einkommensschwachen Gegenden zu ermöglichen. Allerdings wurden bislang wenig praktische Erfahrungen methodisch über grundlegende Aspekte der Anlagendimensionierung und Anlagenleistungsfähigkeit aufgenommen. Im Rahmen dieser Dissertation wurden anaerobe Reaktoren kommunaler DEWATS unter tropischen Feldbedingungen untersucht, um eine Datengrundlage für zukünftige Dimensionierung, Wartung und Betrieb, als auch Monitoring der Anlagen zu schaffen. Schwerpunkt wurde dabei auf den Anaerobic Baffled Reactor (ABR) als Kerntechnologie von DEWATS gelegt. Felduntersuchungen wurden in der Zeit von mehr als vier Jahren an zahlreichen kommunalen DEWATS in Indonesien, Indien und Südafrika durchgeführt, um (i) die gängig gewählten Parameterwerte für Anlagen-Dimensionierung und -Betrieb zu überprüfen, (ii) leistungslimitierende Faktoren im Feldbetrieb zu identifizieren und um (iii) die Leistungsfähigkeit von DEWATS und DEWATS-Reinigungsstufen (insbesondere des ABRs) unter tropischen Feldbedingungen bezüglich Abflusskonzentrationen, Reduzierung des Chemischen Sauerstoffbedarfs (CSB), Schlammstabilisierung und Schlammaktivität zu untersuchen. Basierend auf den Untersuchungsergebnissen, wurden durchschnittliche Einwohnergleichwerte, Langzeitvariationen und Faktoren für Zuflussspitzen für kommunale Abwasserproduktion in DEWATS-Zielbevölkerungsgruppen präsentiert. Ferner werden allgemeine Pro-Kopf-CSB-Frachten, -Ammoniumfrachten und -Phosphorfrachten, die Pro-Kopf-Biogasproduktion in kommunalen Biogasanlagen sowie die Pro-Kopf-Schlammakkumulation in ABRs abgeschätzt. Auf Felduntersuchungen basierend, wurden Fremdwassereinfluss, generelle Unterbelastung, organische Unterbelastung und erhöhte Frischwassersalinität in Küstengebieten als leistungslimitierende Faktoren im Feldbetrieb identifiziert. An 109 indonesischen Anlagen durchgeführte Abflusskonzentrationsmessungen ließen auf eine garantierte Abflusskonzentration der anaeroben Reaktoren von 200 mg CSB l-1 schließen, wenn der negative Einfluss von erhöhter Frischwassersalinität ausgeschlossen werden kann. Der CSB-Abbau durch ABRs in vier detailliert untersuchten DEWATS war gering in drei Fällen und befriedigend in einem Fall. Anaerobe Filter (AF) trugen in den drei Fällen, in denen sie Teil der Anlagenkonfigurationen waren, signifikant zur CSB-Reduzierung bei. Ammonium- und Phoshorkonzentrationen in allen Reaktorabläufen waren vergleichsweise hoch. Ein großer Anteil des CSBs in Reaktorabläufen war biologisch abbaubar. Es wird die Hypothese aufgestellt, dass sich die Leistungsfähigkeiten der Anlagen signifikant verbessern würden, wären die Anlagenbelastungen den Auslegungswerten ähnlicher, d.h., wären die maximalen hydraulischen Belastungen geringer und die organischen Belastungen höher. Es wird deshalb geraten, den Fremdwasserzufluss zu minimieren, die Anlagenzulaufkonzentration durch partielle Grauwasserversickerung zu erhöhen und die Ammonium- und Phoshorkonzentration im Zulauf durch partiellen Urinabschlag zu verringern. Es wird außerdem vorgeschlagen, die hydraulische Aufenthaltszeit in Absetzbecken (settlers) auf zehn Stunden zu begrenzen, um so die organische Belastung der ABRs zu erhöhen. Ferner wird die Hypothese aufgestellt, dass Anlagen unter höherer Trockenwetterbelastung als bislang angenommen betrieben werden können, da aktiver anaerober Abbau auch unter extremen hydraulischen Belastungen möglich erscheint. Dies könnte zu einer signifikanten Senkung der Baukosten führen. Die Modellierung anaerober Abbauprozesse mit dem existierenden ADM-3P-Modell bestätigten, dass im Feld beobachtete Schlammakkumulationsraten auf eine aktive Hydrolyse schließen lassen. Das Modell konnte jedoch nicht genutzt werden, um Bezugswerte für den gelösten CSB im Ablauf der Anlagen zu erhalten, da es eine vergleichsweise hohe Sensitivität in Bezug auf die Raten für Methanogenese aufwies. Die allgemein anerkannte Sichtweise ist, dass die Hydrolyse den geschwindigkeitsbestimmenden Abbauschritt bei der anaeroben Behandlung feststoffreicher Abwässer darstellt. Es wird die Hypothese aufgestellt, dass dieses nicht für feststoffakkumulierende Systeme, wie den ABR, zutrifft.
199

Climate variability: Human management response to environmental changes in Touws River valley and Makolokwe

Llale, Semakaleng January 2020 (has links)
Magister Artium - MA / Climate has been changing significantly around the globe; hence climate variability is of great interest to researchers. The changes in climate have caused variances in rainfall and temperature, both elements of paramount importance in farming, whether commercial or communal farming. As these fluctuations in temperature and rainfall occur, they cause direct impacts on different livelihoods, fauna and flora. The aim of this thesis is to investigate the human management responses of farmers in two different contexts of communal farming (Makolokwe) and commercial farming (Touws River valley), with a focus investigation on the adaptation and coping strategies of the farmers, as well as spatial analysis of the vegetation and rainfall variability. Farmers were asked to discuss climate and adaptation based on the rainfall data available as well as far as they could remember the occurrence of changes. Rainfall data was available between 1988 and 2017 for Touws River, while the data utilised for Makolokwe was available between 1928 and 2016. The link between the local knowledge of the farmers and scientific knowledge is an important aspect of this research. The Normalised Difference Vegetation Index (NDVI) was used to analyse the vegetation changes on a temporal and spatial scale in the context of Makolokwe and Touws River valley respectively. The differing variations in climate variability and change experienced by the two farming communities are placed alongside an exploration of the adaptation and coping measures which are put in place by farmers as a response to the changes evident in climate, as it allows for better and thorough understanding of the occurring changes in the two communities. The study found that perceptions about climate variability vary in the two communities although there are some common factors. Farmers’ perceptions about climate variability are drawn from their own observations at a local level as well as knowledge from the media regarding terms such as El Niño and drought. Farmers in both communities indicated that they experienced insufficient rain in the winter months which had an impact on the grazing areas and the management of the livestock. These months also threatened livelihoods, especially for farmers who depend on their livestock for their livelihood, in particular communal farmers. Perceptions of factors such as decreasing grazing and vegetation in their environments have led to the adoption of adaptation and coping strategies on the part of farmers. Commercial farmers have more choices in this regard than communal farmers, such as converting to game farming. Common coping strategies include: (1) farmers have had to subsidise and use alternative food sources for the livestock, (2) livestock numbers have been reduced in order to adapt to climate variability, with an impact on livelihoods (3) farmers have had to rely on their hope and faith that things will get better. Planning for climate variability is challenging for land managers. Knowledge and access to resources is therefore essential in ensuring that farmers are kept on track with the changing environment.
200

Livestock production and animal health management systems in communal farming areas at the wildlife-livestock interface in southern Africa

Van Rooyen, Jacques January 2016 (has links)
Development of transfrontier conservation areas (TFCAs) in southern Africa depends, among other, on the ability of stakeholders to find practical and sustainable solutions for wildlife‐livestock integration in the conservation landscape. Due to the presence of buffalo Syncerus caffer in most of the TFCAs in southern Africa, foot‐and‐mouth disease (FMD) has to be controlled in susceptible livestock species sharing the rangelands with wildlife. Conventional FMD control measures act as an additional burden on communal livestock producers and may hamper rural development and wildlife‐livestock integration even further. However, commodity‐based trade in the form of an integrated approach to the control of both food safety and disease risk along the entire beef value chain has been proposed as a more favourable alternative for ensuring market access for beef produced at the wildlife‐livestock interface. Such a non‐geographic based approach could allow for trade to continue despite high risk of FMD if appropriate disease risk and food safety measures are implemented by farmers and subsequent role players along the value chain and hence, could promote greater wildlife‐livestock compatibility. / The objective of the present study was to analyse beef production, health and trade systems of farmers at the wildlife‐livestock interface within foot‐and‐mouth disease (FMD) protection zones in order to identify challenges, risks and limitations that may limit compliance with proposed commodity‐based trade prerequisites as well as value chain participation. Based on the findings of this study a holistic, integrated approach is proposed at the village level that could be implemented to serve as an incentive for equitable participation by farmers whilst 1) addressing the risks and limitations of a farming system, 2) ensuring greater wildlife‐livestock compatibility, and 3) promote consistent market access by fulfilling the requirements of an integrated value chain approach based on commodity‐based trade standards. / A farming systems approach was used to investigate beef production, health and trade systems in FMD protection zones mainly within the Zambezi Region (ZR) of Namibia, which is situated within the KAZA TFCA (Kavango‐Zambezi Transfrontier Conservation Area), but also the Mnisi study area (MSA) in South Africa adjacent to the Great Limpopo Transfrontier Conservation Area (GLTFCA). A combined qualitative and quantitative approach was used to assess and describe farmers’ perceptions in selected study areas about beef production, trade, and wildlife conservation. Secondary data obtained from state veterinary services, the Meatco abattoir in Katima Mulilo, as well as previous studies were analysed and modelled to describe spatial‐temporal trends in trade as well as cattle distribution in relation to resource availability. / The results indicate that beef production systems in some of the most remote areas of the ZR as well as in the MSA resemble a typical low‐input low‐output production system, mainly due to the high level of risk farmers had to cope with and the limited opportunity to offset losses. The major challenges within livestock farming in all the areas studied were animal diseases, grazing competition, predation, stock theft and contact with wildlife, although the importance of each varied between study areas. Herd size effect in the MSA significantly explained the variation in attitude towards trade, production and management of cattle between farmers with below average and farmers with above average herd sizes. In the MSA, home slaughter contributed significantly more to direct household food security in households with larger herd sizes than in households with smaller herd sizes, and in the ZR farmers with smaller herd sizes were discouraged from participation in formal trade. / The attitudes and perceptions of farmers In the ZR towards wildlife and conservation often varied between survey areas as a consequence of the variation in the geophysical properties of the landscape, proximity to conservation areas, as well as the form of the interface with conservation areas. The perceived spatial‐temporal movement of buffalo varied between survey areas in the ZR. However, the frequency and nature of buffalo‐cattle interaction was generally high and intimate. Most farmers associated buffalo with risk of disease, especially FMD, but some were more concerned about grazing competition and the negative effect on husbandry practises. Farmers readily deployed traditional risk mitigation tactics in the form of kraaling at night and herding at day to control the movement of their animals and to reduce risks. Herding was found to be a potential strategy to specifically mitigate cattlebuffalo contact despite the lack of evidence that an overall strategic approach to herding exist. Although the majority of farmers in the ZR were in favour of conservation and its benefits, the negative impact of increasing wildlife numbers on farmers’ attitudes was an indication that the generally positive sentiment was changing and may in future deter conservation efforts. / Indications are that the cattle population in the ZR at its estimated density and distribution had reached the ecological capacity of the natural resource base in the ZR and animal performance and survival was therefore subjected to increased variability in resource availability linked to climate change. The cattle population’s existence at ecological capacity and the inability of farmers to offset the loss of condition in the dry season with supplementary feed were reflected in the changes in carcass quality and grades across seasons. However, there was sufficient forage produced in the ZR to sustain animal performance to some extent throughout the year, but those areas with surplus forage existed beyond the assumed grazing range around villages and perennial rivers where most cattle and wildlife concentrate. The future ability of farmers to access such underutilised grazing resources in order to strategically counter the negative consequences of climate change and growing wildlife numbers could be an important coping and risk management mechanism linked to commodity‐based trade and sustained animal quality. / Regular FMD outbreaks had a significant impact on the consistency with which the Meatco abattoir in the ZR operated between the years 2007‐2011, with negative consequences to both farmers and the abattoir itself. It was found that the formal trade system in the ZR discriminated against farmers with below average herd sizes, and that the disposition held by farmers with smaller herd sizes are most significant in areas further than approximately 55km away from quarantine camps. Vegetation type and possible contact with buffalo or previous FMD outbreaks in the area did not significantly affect market participation nor off‐take rates at a crush‐pen level in the ZR. The negative effect that distance from a quarantine station had on formal off‐take rate and the level of sales to Meatco at crush‐pen level, was the most significant in the winter months and crush‐pens situated beyond 55km from a quarantine station. The results indicate that the trade range of the Meatco abattoir was less than its trade threshold which contributed to its struggle to sustain throughput and profitability. / Finally the loss of income farmers experienced in both the ZR and the MSA during simultaneous FMD outbreaks in the year 2012 was quantified, as well as the impact it had on livelihoods in the ZR. A commodity‐based trade approach may have reduced the impact on farmers’ income significantly. However, we farmers are unable to comply with the proposed requirements for mitigating risk and ensuring food safety and quality in such communal systems in the absence of interventions to build the necessary capacity and awareness. It is recommended that at the wildlife‐livestock interface such as those investigated in this study, an integrated value chain approach to trade could serve as a catalyst to incentivise and enable farmer participation in holistic, integrated rangeland and livestock management practises that will promote conservation and rural development. / Thesis (PhD)--University of Pretoria, 2016. / The Institute for Tropical Medicine, Antwerp, Belgium / University of Pretoria / National Research Foundation of South Africa / Veterinary Tropical Diseases / PhD / Unrestricted

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