The trophic ecology of parrotfish of Zanzibar application of stable isotope analysis
- Plass-Johnson, Jeremiah Grahm
- Authors: Plass-Johnson, Jeremiah Grahm
- Date: 2012
- Subjects: Parrotfishes -- Tanzania -- Zanzibar , Parrotfishes , Parrotfishes -- Ecology -- Tanzania -- Zanzibar , Parrotfishes -- Behavior -- Tanzania -- Zanzibar , Parrotfishes -- Food -- Tanzania -- Zanzibar , Scleractinia -- Tanzania -- Zanzibar , Algae -- Tanzania -- Zanzibar , Coral reefs and islands -- Tanzania -- Zanzibar , Coral reef fishes -- Tanzania -- Zanzibar , Stable isotopes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5789 , http://hdl.handle.net/10962/d1005477 , Parrotfishes -- Tanzania -- Zanzibar , Parrotfishes , Parrotfishes -- Ecology -- Tanzania -- Zanzibar , Parrotfishes -- Behavior -- Tanzania -- Zanzibar , Parrotfishes -- Food -- Tanzania -- Zanzibar , Scleractinia -- Tanzania -- Zanzibar , Algae -- Tanzania -- Zanzibar , Coral reefs and islands -- Tanzania -- Zanzibar , Coral reef fishes -- Tanzania -- Zanzibar , Stable isotopes
- Description: Parrotfish are a critical component of the herbivore functional group on tropical coral reefs around the world because they mediate competition that occurs between algae and scleractinian corals. Also, because of their feeding technique, which consists of rasping at the substratum with their beak-like teeth, they play an important role in carbonate turnover and the clearing of reef surface area for the settlement of new sessile organisms. Because of these roles, parrotfishes are an important structuring component of coral reef communities. However, individual species can play different roles depending on their physiology, behaviour and ecology. Despite the possible ecological differences that may exist amongst species, specific roles of the fishes remain unclear as the group is most often studied at higher community levels. This thesis applied stable isotope analysis to differing levels of organisation within a parrotfish community to help elucidate their trophic ecology on coral reefs in Zanzibar. Firstly, blood and muscle tissues were compared to identify differences in their isotope signatures. In other organisms, blood turns over faster than muscle tissue so that muscle tissue represents the diet as integrated over a longer period of time. In most species of parrotfish the blood and muscle δ¹³C signatures were not found to be significantly different, but the δ¹⁵N signatures were significantly different between tissues. This indicated that the δ¹³C signature of both tissues would reveal similar dietary information. Conversely, differences in the δ¹⁵N signature indicated that the nitrogen relationship between tissues was more complicated. Secondly, spatial variability in parrotfish, coral, detritus and macroalgae isotope signatures was assessed at different scales. In macroalgae and coral tissues (zooxanthellae and polyp treated separately), the δ¹³C signatures were shown to differ with depth, presumably because of changes in photosynthetic processes related to depth-associated changes in light. While δ¹⁵N signatures were not affected by depth, all organisms showed enrichment at the Nyange reef, the closest reef to the capital of Zanzibar, Stone Town, presumably reflecting the effects of sewage outfall. These results show that processes that impact the δ¹⁵N signatures of primary producers (macroalgae and zooxanthellae) can be traced to higher trophic levels (coral polyps and fish). Lastly, δ¹³C and δ¹⁵N signatures were used to identify ontogenetic dietary changes in multiple species of parrotfish. Four of the species showed stages that varied from the diets that are normally assumed on the basis of their dentition and feeding technique. This indicates that functional roles based on taxonomy or morphology may fail to include possible ontogenetic dietary changes, and may also fail to elucidate the full impact a species could have on coral reef communities. The conclusions from these studies indicate that the species-specific ecological role of parrotfish in coral reef communities can be complex within and between species, and may differ amongst reefs. In light of the natural and anthropogenic pressures that affect coral reef systems, management decisions based on a more complete understanding of the role of these fish in coral reef communities will help decisions that maintain resilience in these fragile systems.
- Full Text:
- Date Issued: 2012
- Authors: Plass-Johnson, Jeremiah Grahm
- Date: 2012
- Subjects: Parrotfishes -- Tanzania -- Zanzibar , Parrotfishes , Parrotfishes -- Ecology -- Tanzania -- Zanzibar , Parrotfishes -- Behavior -- Tanzania -- Zanzibar , Parrotfishes -- Food -- Tanzania -- Zanzibar , Scleractinia -- Tanzania -- Zanzibar , Algae -- Tanzania -- Zanzibar , Coral reefs and islands -- Tanzania -- Zanzibar , Coral reef fishes -- Tanzania -- Zanzibar , Stable isotopes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5789 , http://hdl.handle.net/10962/d1005477 , Parrotfishes -- Tanzania -- Zanzibar , Parrotfishes , Parrotfishes -- Ecology -- Tanzania -- Zanzibar , Parrotfishes -- Behavior -- Tanzania -- Zanzibar , Parrotfishes -- Food -- Tanzania -- Zanzibar , Scleractinia -- Tanzania -- Zanzibar , Algae -- Tanzania -- Zanzibar , Coral reefs and islands -- Tanzania -- Zanzibar , Coral reef fishes -- Tanzania -- Zanzibar , Stable isotopes
- Description: Parrotfish are a critical component of the herbivore functional group on tropical coral reefs around the world because they mediate competition that occurs between algae and scleractinian corals. Also, because of their feeding technique, which consists of rasping at the substratum with their beak-like teeth, they play an important role in carbonate turnover and the clearing of reef surface area for the settlement of new sessile organisms. Because of these roles, parrotfishes are an important structuring component of coral reef communities. However, individual species can play different roles depending on their physiology, behaviour and ecology. Despite the possible ecological differences that may exist amongst species, specific roles of the fishes remain unclear as the group is most often studied at higher community levels. This thesis applied stable isotope analysis to differing levels of organisation within a parrotfish community to help elucidate their trophic ecology on coral reefs in Zanzibar. Firstly, blood and muscle tissues were compared to identify differences in their isotope signatures. In other organisms, blood turns over faster than muscle tissue so that muscle tissue represents the diet as integrated over a longer period of time. In most species of parrotfish the blood and muscle δ¹³C signatures were not found to be significantly different, but the δ¹⁵N signatures were significantly different between tissues. This indicated that the δ¹³C signature of both tissues would reveal similar dietary information. Conversely, differences in the δ¹⁵N signature indicated that the nitrogen relationship between tissues was more complicated. Secondly, spatial variability in parrotfish, coral, detritus and macroalgae isotope signatures was assessed at different scales. In macroalgae and coral tissues (zooxanthellae and polyp treated separately), the δ¹³C signatures were shown to differ with depth, presumably because of changes in photosynthetic processes related to depth-associated changes in light. While δ¹⁵N signatures were not affected by depth, all organisms showed enrichment at the Nyange reef, the closest reef to the capital of Zanzibar, Stone Town, presumably reflecting the effects of sewage outfall. These results show that processes that impact the δ¹⁵N signatures of primary producers (macroalgae and zooxanthellae) can be traced to higher trophic levels (coral polyps and fish). Lastly, δ¹³C and δ¹⁵N signatures were used to identify ontogenetic dietary changes in multiple species of parrotfish. Four of the species showed stages that varied from the diets that are normally assumed on the basis of their dentition and feeding technique. This indicates that functional roles based on taxonomy or morphology may fail to include possible ontogenetic dietary changes, and may also fail to elucidate the full impact a species could have on coral reef communities. The conclusions from these studies indicate that the species-specific ecological role of parrotfish in coral reef communities can be complex within and between species, and may differ amongst reefs. In light of the natural and anthropogenic pressures that affect coral reef systems, management decisions based on a more complete understanding of the role of these fish in coral reef communities will help decisions that maintain resilience in these fragile systems.
- Full Text:
- Date Issued: 2012
Universal approximation properties of feedforward artificial neural networks.
- Authors: Redpath, Stuart Frederick
- Date: 2011
- Subjects: Neural networks (Computer science) , Artificial intelligence -- Biological applications , Functional analysis , Weierstrass-Stone Theorem , Banach-Hahn theorem
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5430 , http://hdl.handle.net/10962/d1015869
- Description: In this thesis we summarise several results in the literature which show the approximation capabilities of multilayer feedforward artificial neural networks. We show that multilayer feedforward artificial neural networks are capable of approximating continuous and measurable functions from Rn to R to any degree of accuracy under certain conditions. In particular making use of the Stone-Weierstrass and Hahn-Banach theorems, we show that a multilayer feedforward artificial neural network can approximate any continuous function to any degree of accuracy, by using either an arbitrary squashing function or any continuous sigmoidal function for activation. Making use of the Stone-Weirstrass Theorem again, we extend these approximation capabilities of multilayer feedforward artificial neural networks to the space of measurable functions under any probability measure.
- Full Text:
- Date Issued: 2011
- Authors: Redpath, Stuart Frederick
- Date: 2011
- Subjects: Neural networks (Computer science) , Artificial intelligence -- Biological applications , Functional analysis , Weierstrass-Stone Theorem , Banach-Hahn theorem
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5430 , http://hdl.handle.net/10962/d1015869
- Description: In this thesis we summarise several results in the literature which show the approximation capabilities of multilayer feedforward artificial neural networks. We show that multilayer feedforward artificial neural networks are capable of approximating continuous and measurable functions from Rn to R to any degree of accuracy under certain conditions. In particular making use of the Stone-Weierstrass and Hahn-Banach theorems, we show that a multilayer feedforward artificial neural network can approximate any continuous function to any degree of accuracy, by using either an arbitrary squashing function or any continuous sigmoidal function for activation. Making use of the Stone-Weirstrass Theorem again, we extend these approximation capabilities of multilayer feedforward artificial neural networks to the space of measurable functions under any probability measure.
- Full Text:
- Date Issued: 2011
Effect of salinity on oxygen consumption and growth of juvenile white steenbras, litohognathus lithognathus
- Authors: Kandjou, Kaunahama
- Date: 2008
- Subjects: Lithognathus -- Growth , Salinity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5275 , http://hdl.handle.net/10962/d1005119 , Lithognathus -- Growth , Salinity
- Description: A stress-induced increase in metabolic rate of fish consumes energy within the metabolic scope of a fish that could otherwise be used for such functions as growth and reproduction. By estimating the degree of the metabolic response under given salinity levels and sudden changes thereof, it could be tested whether growth under given culture conditions could be predicted. Using intermittent respirometers, this study investigated the metabolic response of juvenile Lithognathus lithognathus following gradual acclimation to 5, 25 and 35‰ and, as a result of abrupt change from 35‰ to 5‰ or from 35‰ to 25‰ at 20˚C. The main aim of the study was to establish whether the magnitude of such responses could be used to predict growth of juvenile L. lithognathus under culture conditions. Hence, in addition to the respirometry study, two growth studies were conducted at 5, 10, 25 and 35‰ salinities. The baseline metabolic rates of juvenile L. lithognathus were also determined. Oxygen consumption measurements over 24-hours showed that most fish exhibited a diurnal peak in metabolic rates. The standard and active metabolic rates calculated from juvenile L. lithognathus with a diurnal peak in oxygen consumption were 0.06±0.001mgO₂g⁻¹h⁻¹ (mean±SEM, n = 5), and 0.11±0.01mg O₂g⁻¹h⁻¹, respectively. The standard and active metabolic rates of juvenile L lithognathus showing a nocturnal peak in metabolic activities were 0.04±0.001mgO₂g-1h-1 (n = 1), and 0.12±0.003 mg O₂g⁻¹ h⁻¹, respectively. Routine metabolic rate of these fish calculated over a 3-h measurement period was 0.09±0.005mgO₂g⁻¹h⁻¹ (n = 6). Juvenile L. lithognathus showed a relationship between metabolic rate (mo₂) and body weight (W) following the equation: mo₂ = 0.62 W⁻°·⁵³.
- Full Text:
- Date Issued: 2008
- Authors: Kandjou, Kaunahama
- Date: 2008
- Subjects: Lithognathus -- Growth , Salinity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5275 , http://hdl.handle.net/10962/d1005119 , Lithognathus -- Growth , Salinity
- Description: A stress-induced increase in metabolic rate of fish consumes energy within the metabolic scope of a fish that could otherwise be used for such functions as growth and reproduction. By estimating the degree of the metabolic response under given salinity levels and sudden changes thereof, it could be tested whether growth under given culture conditions could be predicted. Using intermittent respirometers, this study investigated the metabolic response of juvenile Lithognathus lithognathus following gradual acclimation to 5, 25 and 35‰ and, as a result of abrupt change from 35‰ to 5‰ or from 35‰ to 25‰ at 20˚C. The main aim of the study was to establish whether the magnitude of such responses could be used to predict growth of juvenile L. lithognathus under culture conditions. Hence, in addition to the respirometry study, two growth studies were conducted at 5, 10, 25 and 35‰ salinities. The baseline metabolic rates of juvenile L. lithognathus were also determined. Oxygen consumption measurements over 24-hours showed that most fish exhibited a diurnal peak in metabolic rates. The standard and active metabolic rates calculated from juvenile L. lithognathus with a diurnal peak in oxygen consumption were 0.06±0.001mgO₂g⁻¹h⁻¹ (mean±SEM, n = 5), and 0.11±0.01mg O₂g⁻¹h⁻¹, respectively. The standard and active metabolic rates of juvenile L lithognathus showing a nocturnal peak in metabolic activities were 0.04±0.001mgO₂g-1h-1 (n = 1), and 0.12±0.003 mg O₂g⁻¹ h⁻¹, respectively. Routine metabolic rate of these fish calculated over a 3-h measurement period was 0.09±0.005mgO₂g⁻¹h⁻¹ (n = 6). Juvenile L. lithognathus showed a relationship between metabolic rate (mo₂) and body weight (W) following the equation: mo₂ = 0.62 W⁻°·⁵³.
- Full Text:
- Date Issued: 2008
Building cultural capital through value-driven leadership: a case study in an international finance company
- Authors: Ackerman, Mariana
- Date: 2006
- Subjects: Financial institutions, International -- Namibia Case studies , Leadership -- Namibia Case studies , Corporate culture -- Namibia Case studies , Organizational change -- Namibia Case studies , Organizational effectiveness -- Namibia Case studies
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:2919 , http://hdl.handle.net/10962/d1002428 , Financial institutions, International -- Namibia Case studies , Leadership -- Namibia Case studies , Corporate culture -- Namibia Case studies , Organizational change -- Namibia Case studies , Organizational effectiveness -- Namibia Case studies
- Description: Today, organizations are placed under extreme pressure to adapt to the ever-increasing changes in their environments in order to survive. Research proves that corporate culture has the ability to either blunt or aid change. Past research conducted in Z-Nam, a subsidiary of an international finance company situated in Namibia, indicated that a divided culture resulted in limitations in their functioning, including their adaptability. Pressure was placed on Z-Nam by its majority shareholder to internalise a set of core values into its daily functioning in order to build a strong adaptable culture. This objective called for values-driven leadership. The four core values identified by Head Office were integrity, respect, accountability and pushing beyond boundaries. In becoming more values-driven, values theory posits that Z-Nam will build its cultural capital and so reap the benefits of higher performance, talent retention and adaptability. In this way Z-Nam will be able to combat the weaknesses in its current culture. Leadership adaptability and the capacity to lead change were seen to distinguish cultural changes that succeed from those that do not. Principles inherent in the field of OD were also considered, as they are seen to assist in the effective management of change. The methodology involved a purposive sample being drawn that included the top leadership team and internal OD consultant. Semi-structured interviews were conducted and thematic analysis employed in analysing the resultant data with three main aims in mind. Firstly, to assess Z-Nam's top management's perception of the current set of values being lived in the organization, to establish their level of support for the desired set of values proposed by Head Office and lastly to establish whether the leadership team is ready to promote the adoption of a new set of core values. Through comparing the themes that emerged from the data with literature on OD, values, culture and change, the researcher was able to make inferences as to the leadership's readiness and capacity to successfully lead cultural change. These findings were substantiated with secondary data from previous research activities. It was found that Z-Nam was not utilising its culture as an asset and that several barriers existed to adopting and implementing the desired values. It was concluded that Z-Nam will not be able to successfully embark on cultural change until its leadership recognises the importance of culture and their personal responsibility in bringing about the desired change, adequately assimilates information from past research and comes to a consensus as to the necessary accommodations that need to be made.
- Full Text:
- Date Issued: 2006
- Authors: Ackerman, Mariana
- Date: 2006
- Subjects: Financial institutions, International -- Namibia Case studies , Leadership -- Namibia Case studies , Corporate culture -- Namibia Case studies , Organizational change -- Namibia Case studies , Organizational effectiveness -- Namibia Case studies
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:2919 , http://hdl.handle.net/10962/d1002428 , Financial institutions, International -- Namibia Case studies , Leadership -- Namibia Case studies , Corporate culture -- Namibia Case studies , Organizational change -- Namibia Case studies , Organizational effectiveness -- Namibia Case studies
- Description: Today, organizations are placed under extreme pressure to adapt to the ever-increasing changes in their environments in order to survive. Research proves that corporate culture has the ability to either blunt or aid change. Past research conducted in Z-Nam, a subsidiary of an international finance company situated in Namibia, indicated that a divided culture resulted in limitations in their functioning, including their adaptability. Pressure was placed on Z-Nam by its majority shareholder to internalise a set of core values into its daily functioning in order to build a strong adaptable culture. This objective called for values-driven leadership. The four core values identified by Head Office were integrity, respect, accountability and pushing beyond boundaries. In becoming more values-driven, values theory posits that Z-Nam will build its cultural capital and so reap the benefits of higher performance, talent retention and adaptability. In this way Z-Nam will be able to combat the weaknesses in its current culture. Leadership adaptability and the capacity to lead change were seen to distinguish cultural changes that succeed from those that do not. Principles inherent in the field of OD were also considered, as they are seen to assist in the effective management of change. The methodology involved a purposive sample being drawn that included the top leadership team and internal OD consultant. Semi-structured interviews were conducted and thematic analysis employed in analysing the resultant data with three main aims in mind. Firstly, to assess Z-Nam's top management's perception of the current set of values being lived in the organization, to establish their level of support for the desired set of values proposed by Head Office and lastly to establish whether the leadership team is ready to promote the adoption of a new set of core values. Through comparing the themes that emerged from the data with literature on OD, values, culture and change, the researcher was able to make inferences as to the leadership's readiness and capacity to successfully lead cultural change. These findings were substantiated with secondary data from previous research activities. It was found that Z-Nam was not utilising its culture as an asset and that several barriers existed to adopting and implementing the desired values. It was concluded that Z-Nam will not be able to successfully embark on cultural change until its leadership recognises the importance of culture and their personal responsibility in bringing about the desired change, adequately assimilates information from past research and comes to a consensus as to the necessary accommodations that need to be made.
- Full Text:
- Date Issued: 2006
The relative influence of value priorities ethnicity and worries in the determination of political party affiliation amongst Ugandan university students
- Authors: Kibanja, Grace M
- Date: 1999
- Subjects: Political psychology , Uganda -- Politics and government -- 1979- , Students -- Uganda -- Political activity , College students -- Uganda -- Psychology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3003 , http://hdl.handle.net/10962/d1002512 , Political psychology , Uganda -- Politics and government -- 1979- , Students -- Uganda -- Political activity , College students -- Uganda -- Psychology
- Description: This study examines the relative influence of value priorities, ethnicity and 'worries' in the determination of political party affiliation amongst Ugandan university students. Schwartz's values questionnaire was administered to 309 male and 176 female first year students from the faculties of engineering, medicine, law, commerce, social sciences, sciences, education and mass communication at Makerere University Uganda. The sample included respondents from all of the six sub-ethnic groups in Uganda. Respondents also covered the major religious groups in the country and were also representative of the major political parties. Results from the statistical analysis on the data show that ethnicity and certain values playa role in the determination of these students' affiliation to a political party. Chi-square results show that achievement, benevolence, universalism, security, tradition and conformity values are given differing importance across political parties. And, Anova results show that the tradition value has a significant mean difference across parties. Other factors such as religion and course of study are also found to have significant influence on these student's affiliation to political parties. Although 'worries' are found not to have a significant influence on student's political party affiliation, findings show that students from different political parties differ in their ratings of the different types of ' worries'. Therefore results show that ethnicity and value priorities do infl4ence these students' affiliation to a political party but ' worries' do not. The discussion section explores these findings in the context of contemporary Ugandan politics.
- Full Text:
- Date Issued: 1999
- Authors: Kibanja, Grace M
- Date: 1999
- Subjects: Political psychology , Uganda -- Politics and government -- 1979- , Students -- Uganda -- Political activity , College students -- Uganda -- Psychology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3003 , http://hdl.handle.net/10962/d1002512 , Political psychology , Uganda -- Politics and government -- 1979- , Students -- Uganda -- Political activity , College students -- Uganda -- Psychology
- Description: This study examines the relative influence of value priorities, ethnicity and 'worries' in the determination of political party affiliation amongst Ugandan university students. Schwartz's values questionnaire was administered to 309 male and 176 female first year students from the faculties of engineering, medicine, law, commerce, social sciences, sciences, education and mass communication at Makerere University Uganda. The sample included respondents from all of the six sub-ethnic groups in Uganda. Respondents also covered the major religious groups in the country and were also representative of the major political parties. Results from the statistical analysis on the data show that ethnicity and certain values playa role in the determination of these students' affiliation to a political party. Chi-square results show that achievement, benevolence, universalism, security, tradition and conformity values are given differing importance across political parties. And, Anova results show that the tradition value has a significant mean difference across parties. Other factors such as religion and course of study are also found to have significant influence on these student's affiliation to political parties. Although 'worries' are found not to have a significant influence on student's political party affiliation, findings show that students from different political parties differ in their ratings of the different types of ' worries'. Therefore results show that ethnicity and value priorities do infl4ence these students' affiliation to a political party but ' worries' do not. The discussion section explores these findings in the context of contemporary Ugandan politics.
- Full Text:
- Date Issued: 1999
Geological controls for coal exploration and mining
- Authors: Noppé , Mark Adrian
- Date: 1992
- Subjects: Coal -- Geology , Coal mines and mining
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4954 , http://hdl.handle.net/10962/d1005566 , Coal -- Geology , Coal mines and mining
- Description: The identification and interpretation of geological features is essential for the planning and ultimate success of any mining venture. Examples of geological features significant for mining are presented, and their identification during exploration discussed. In particular, the importance of coal qualities, seam thickness and seam elevation are emphasised in relation to longwall mining. Geostatistical analysis provides a powerful tool for improving the prediction and decision-making capabilities of both exploration and mine geologists. The availability of geostatistics, and the benefits resulting from its application, are demonstrated using actual data for calorific value, seam thickness and seam elevation. Contamination of run-of-mine coal is a common problem on highly-mechanised collieries. The problem generally arises from over-cutting of the designated mining horizon. A practical system for monitoring and controlling contamination on a mechanised bord-and-pillar and longwall colliery is presented. The results and benefits of applying such a system are cited for an actual longwall colliery. Numerical geological predictions are not always reported in terms of the reliability of such estimates. Many of these values can be reported in terms of confidence limits, particularly for routine grade control purposes. The methods and benefits of such reporting are described and illustrated by way of examples for calorific value and contamination levels.
- Full Text:
- Date Issued: 1992
- Authors: Noppé , Mark Adrian
- Date: 1992
- Subjects: Coal -- Geology , Coal mines and mining
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4954 , http://hdl.handle.net/10962/d1005566 , Coal -- Geology , Coal mines and mining
- Description: The identification and interpretation of geological features is essential for the planning and ultimate success of any mining venture. Examples of geological features significant for mining are presented, and their identification during exploration discussed. In particular, the importance of coal qualities, seam thickness and seam elevation are emphasised in relation to longwall mining. Geostatistical analysis provides a powerful tool for improving the prediction and decision-making capabilities of both exploration and mine geologists. The availability of geostatistics, and the benefits resulting from its application, are demonstrated using actual data for calorific value, seam thickness and seam elevation. Contamination of run-of-mine coal is a common problem on highly-mechanised collieries. The problem generally arises from over-cutting of the designated mining horizon. A practical system for monitoring and controlling contamination on a mechanised bord-and-pillar and longwall colliery is presented. The results and benefits of applying such a system are cited for an actual longwall colliery. Numerical geological predictions are not always reported in terms of the reliability of such estimates. Many of these values can be reported in terms of confidence limits, particularly for routine grade control purposes. The methods and benefits of such reporting are described and illustrated by way of examples for calorific value and contamination levels.
- Full Text:
- Date Issued: 1992
Liquid junction potentials at mixed electrolyte salt bridges
- Authors: Finkelstein, Noel Phillip
- Date: 1957
- Subjects: Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4473 , http://hdl.handle.net/10962/d1011835 , Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
- Description: The potentiometric method is one of the most exact techniques of electrochemistry. Its use is widespread in both routine measurements, such as pH determination, and in applications which demand the highest accuracy. Perhaps its severest limitation is the error due to liquid junction potentials. Although this has been the subject of much study, and although various means of combating it have been proposed, it has defied all attempts at a satisfactory solution. Indeed, so serious is the position that it has become the accepted practice in the more accurate fields to abandon altogether the use of potentiometric techniques in favour of others, usually less convenient and otherwise less accurate, when the presence of liquid junctions cannot be avoided. Intro. p. 1.
- Full Text:
- Date Issued: 1957
- Authors: Finkelstein, Noel Phillip
- Date: 1957
- Subjects: Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4473 , http://hdl.handle.net/10962/d1011835 , Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
- Description: The potentiometric method is one of the most exact techniques of electrochemistry. Its use is widespread in both routine measurements, such as pH determination, and in applications which demand the highest accuracy. Perhaps its severest limitation is the error due to liquid junction potentials. Although this has been the subject of much study, and although various means of combating it have been proposed, it has defied all attempts at a satisfactory solution. Indeed, so serious is the position that it has become the accepted practice in the more accurate fields to abandon altogether the use of potentiometric techniques in favour of others, usually less convenient and otherwise less accurate, when the presence of liquid junctions cannot be avoided. Intro. p. 1.
- Full Text:
- Date Issued: 1957
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