title: Real Time NMR Analysis of Melamine Formaldehyde Resin Reactions

authors: Wang, Yuan

subjects: Melamine

abstract: This investigation was carried out on behalf of the Momentive Specialty Chemicals Pty Ltd, Mt Maunganui. The aim of the investigation was to develop a method to analyse the formation of melamine formaldehyde resins via an in situ real time NMR experiment leading to quantitative NMR intensities of the resin up to the stages of its Industrial Resin Endpoint (IRE). 
In order to run an in situ reaction for the melamine formaldehyde resin system and monitor it in real time, both qualitative and quantitative NMR acquisition methods were required. The qualitative method was power gated and used to obtain results in situ and in real time. However to render it quantitative, it was necessary to develop a quantitative method which was initially executed to obtain a conversion factor for relating the qualitative results obtained in the in situ experiment to quantitative results performed by doing inverse gated NMR spectra on a final form of the resin.  The development of this technique required the determination of the longitudinal relaxation times (T1) of the species within the melamine reaction as these were required to derive the necessary repetition rates employed in the NMR acquisition methods.
In general, this project involved the development of  the above mentioned NMR analytical protocols with tailoring to run this type of experiment in a 5 mm NMR tube using a 400 MHz NMR spectrometer whereby previous research on urea and phenol formaldehyde resins and employing identical NMR methodologies had relied on analyses conducted in a 10 mm NMR tube on a 300 MHz NMR instrument. 
As a result, reaction profiles of the melamine resin reaction were obtained during a real time experiment. The reaction profiles of the addition stage of the melamine resin reaction showed that the increase in the methylol melamine species occurs very fast and is justified by the exponential decay of the methylene glycol species corresponding to the formaldehyde solution. The condensation stages of the resin reaction were also observed until the IRE. The reaction profiles of the ether and methylene bridge links are clearly given showing that ether linkages predominate in the addition stage and plateaus, and methylene linkages only increase after the addition stage of the reaction. They provided insight to the reaction progress corresponding to addition and condensation stages of the melamine resin reaction.

text: Real Time NMR Analysis of Melamine Formaldehyde Resin Reactions This investigation was carried out on behalf of the Momentive Specialty Chemicals Pty Ltd, Mt Maunganui. The aim of the investigation was to develop a method to analyse the formation of melamine formaldehyde resins via an in situ real time NMR experiment leading to quantitative NMR intensities of the resin up to the stages of its Industrial Resin Endpoint (IRE). 
In order to run an in situ reaction for the melamine formaldehyde resin system and monitor it in real time, both qualitative and quantitative NMR acquisition methods were required. The qualitative method was power gated and used to obtain results in situ and in real time. However to render it quantitative, it was necessary to develop a quantitative method which was initially executed to obtain a conversion factor for relating the qualitative results obtained in the in situ experiment to quantitative results performed by doing inverse gated NMR spectra on a final form of the resin.  The development of this technique required the determination of the longitudinal relaxation times (T1) of the species within the melamine reaction as these were required to derive the necessary repetition rates employed in the NMR acquisition methods.
In general, this project involved the development of  the above mentioned NMR analytical protocols with tailoring to run this type of experiment in a 5 mm NMR tube using a 400 MHz NMR spectrometer whereby previous research on urea and phenol formaldehyde resins and employing identical NMR methodologies had relied on analyses conducted in a 10 mm NMR tube on a 300 MHz NMR instrument. 
As a result, reaction profiles of the melamine resin reaction were obtained during a real time experiment. The reaction profiles of the addition stage of the melamine resin reaction showed that the increase in the methylol melamine species occurs very fast and is justified by the exponential decay of the methylene glycol species corresponding to the formaldehyde solution. The condensation stages of the resin reaction were also observed until the IRE. The reaction profiles of the ether and methylene bridge links are clearly given showing that ether linkages predominate in the addition stage and plateaus, and methylene linkages only increase after the addition stage of the reaction. They provided insight to the reaction progress corresponding to addition and condensation stages of the melamine resin reaction.

year: 2012

title: Characteristics and evolution of a dynamic prograding continental margin: the late Neogene Giant Foresets Formation, northern Taranaki Basin, New Zealand

authors: Hansen, Rochelle J.

abstract: The Pliocene-Pleistocene Giant Foresets Formation represents the progradation and development of the modem continental margin in northern Taranaki Basin. The dynamic evolution of this formation is fundamentally linked to a Pliocene-Pleistocene increase in sediment flux sourced from South Island, to extensional graben formation in northern Taranaki Basin, to flexural subsidence in Wanganui Basin, and to uplift and erosion in King Country Basin. The development of the Giant Foresets Formation is summarised in this thesis by a series of paleogeographic maps based on the interpretation of wireline data from hydrocarbon exploration holes, industry-acquired seismic reflection data, and the paleoenvironmental interpretation of foraminiferal data derived from well cuttings samples.

Outbuilding of the modem continental shelf-slope margin began during the Early Miocene as the regressive phase of a 1ˢᵗ-order megacycle. Four 2ⁿᵈ-order cycles superimposed on this megacycle have been identified in Taranaki, Wanganui and King Country Basins. The evolution of the Giant Foresets Formation is closely linked to the youngest two megacycles: the Mid Miocene-earliest Pliocene Whangamomona Group/megacycle, and the mid Pliocene-Pleistocene Rangitikei Supergroup/megacycle. The Whangamomona Group includes the Otunui, Mount Messenger, Urenui and Kiore Formations. The continental margin associated with the Whangamomona Group had only limited extent in southern and eastern parts of Taranaki Basin. The Rangitikei Supergroup in Wanganui Basin includes the Tangahoe Mudstone and younger Plio-Pleistocene sediments. The Giant Foresets Formation represents the Rangitikei Supergroup in northern Taranaki Basin.

Revision of the biostratigraphy of four well sections, and integration with biostratigraphic data from other well sections, has highlighted the development in northern Taranaki Basin of a region-wide unconformity between Miocene (Late Tongaporutuan to Late Kapitean) and Pliocene (Early to mid Opoitian) strata, prior to deposition of the Giant Foresets Formation. This is expressed as a paraconformity across much of the northern part of the Western Stable Platform (Ariki Formation), thinner condensed intervals in the Northern Graben, and an erosional unconformity across the Turi Fault Zone. The Ariki Formation is related to at least three important events: (i) the limited extent of progradation of the Whangamomona Group foreset front; (ii) initiation of extension of the Northern Graben; and (iii), the timing of the Tangahoe pulldown in Wanganui Basin. Palinspastic restoration of a complete seismic reflection profile, and backstripping and decompaction of eleven well sections, suggests that paleobathymetric relief may have been locally important in extending the duration of terrigenous sediment starvation.

Six wireline facies have been identified in the Giant Foresets Formation and underlying units. These are: (i) hemipelagic facies; (ii) basin floor fan facies; (iii) slope fan facies; (iv) shelf facies; (v) slumped facies; and (vi) condensed facies. A number of subfacies have also been identified. Construction of a fence diagram using the facies motifs identified in this study has highlighted the distribution of volcaniclastic versus siliciclastic and hemipelagic sedimentation patterns in both time and space in northern Taranaki Basin. The Miocene was dominated by hemipelagic facies interfingering with coarser lithologies sourced predominantly from reworked volcaniclastic material, which travelled some distance into the northwestern region of northern Taranaki Basin. The Plio-Pleistocene Giant Foresets Formation is characterised by a hemipelagic motif, reflecting the dominantly fine-grained nature of the unit, although the formation displays an overall coarsening-upward trend, reflecting increasing proximity to the advancing foreset front and the development of shelf deposits. Localised Pliocene basin floor fans in the Northern Graben (Mangaa Formation) emphasize the role of the graben as a sink for sedimentation during the Opoitian and Waipipian.

Identification and mapping of more than 70 seismic units within the Giant Foresets Formation in northern Taranaki Basin has allowed the post-Miocene sediment distribution patterns to be characterised. Isopach maps and structure contour maps demonstrate the translation of depocentres through time, and illustrate how the sediment distribution pattern associated with the advancing continental margin gradually changed from one of focused sedimentation in the south, and along the axis of the Northern Graben (Mangaa Formation), to a more linear front. Numerous channels and channel systems have been mapped in the Mangapanian to Nukumaruan shelf succession, often preferentially oriented along the axis of the Northern Graben.

The muddy texture of the Giant Foresets Formation is also shown by the seismic characteristics of the formation, with architectural elements and depositional styles reflecting mud- and mixed mud/sand-rich depositional systems. Basin floor (bottomset) facies are characterised by low- relief mounds and/or gull-wing geometries of channel-levee systems, or sub-parallel reflectors, while slope (foreset) facies are dominated by chaotic reflection configurations consistent with slumped deposits or numerous stacked small-scale channel-levee systems on the middle and lower slope.

Much of the shallowing of water depth in northern Taranaki basin occurred during deposition of bottomset facies. Depositional environments changed from mid/lower bathyal during the Late Pliocene, to upper bathyal during the Waipipian and Mangapanian. However, the most rapid aggradation and progradation of the continental margin occurred during the Mangapanian to Late Nukumaruan, with progradational rates as high as 35 km/m.y. recorded. While the coarsest sediment textures are associated with shelf (topset) facies, and the youngest (degradational) foreset units, examination of benthic foraminiferal samples indicate that there was effective transport from the shelf to the base of slope throughout the depositional history of the Giant Foresets Formation.

A dramatic (uphole) decrease in planktic foraminiferal percentage between the Ariki/ Manganui Formations and the Giant Foresets Formation, with a corresponding change in watermass conditions but no dramatic change in water depth, suggests that the progradation of the continental margin during the latest Miocene and Early Pliocene acted to deflect coastal upwelling cells away from northern Taranaki Basin, decreasing available surface water nutrients, and thus reducing the abundance of planktic foraminifera during this time.

Cyclicity within the Giant Foresets Formation is evident on seismic reflection profiles, in wireline motifs, and from paleontological evidence. Sequences may be defined by a particular wireline motif, or set of motifs, the use of seismic reflection configurations to identify components of depositional environments interpreted to represent regressive (RST) and lowstand (LST) sea level conditions, and through the identification of mixed deep water and shallow water benthic foraminiferal assemblages. Basinward of the shelf margin, the highstand systems tract (HST) is often only represented by a bright, high amplitude and laterally continuous reflector that rolls over into shelf deposits. Transgressive (TST) and HST components of a relative sea level cycle cannot be separated from each other on seismic reflection profiles of the shelf deposits of the Giant Foresets Formation. Sequence boundaries often correspond to a bold seismic reflector horizon. A number of discrete high order sequences have been identified, but many of these cannot be consistently correlated between well sections. However, three levels of cyclicity can be established: 2ⁿᵈ-order cycles related to progradation of the Whangamomona Group and Rangitikei Supergroup, 4ᵗʰ-order (400 ka) cycles, and 5ᵗʰ - order (100 ka) cycles (possibly related to glacio-eustatic controls). Sequences are highly asymmetrical, with most of the deposition occurring during lowering and low sea level conditions. Sediment flux is the predominant factor controlling the seismic character of well sections. However, three levels of cyclicity can be established: 2ⁿᵈ-order cycles related to progradation of the Whangamomona Group and Rangitikei Supergroup, 4ᵗʰ-order (400 ka) cycles, and 5ᵗʰ-order (100 ka) cycles (possibly related to glacio-eustatic controls). Sequences are highly asymmetrical, with most of the deposition occurring during lowering and low sea level conditions. Sediment flux is the predominant factor controlling the seismic character of the Late Opoitian to Mangapanian parts of the Giant Foresets Formation, while changes in relative sea level during the Nukumaruan to Castlecliffian increasingly influenced stratal architecture. The shoreline is not considered to have moved basinward of the shelf break during any of the sea level cycles represented in the Giant Foresets Formation, except possibly for a few cycles during the Late Nukumaruan and Castlecliffian.

text: Characteristics and evolution of a dynamic prograding continental margin: the late Neogene Giant Foresets Formation, northern Taranaki Basin, New Zealand The Pliocene-Pleistocene Giant Foresets Formation represents the progradation and development of the modem continental margin in northern Taranaki Basin. The dynamic evolution of this formation is fundamentally linked to a Pliocene-Pleistocene increase in sediment flux sourced from South Island, to extensional graben formation in northern Taranaki Basin, to flexural subsidence in Wanganui Basin, and to uplift and erosion in King Country Basin. The development of the Giant Foresets Formation is summarised in this thesis by a series of paleogeographic maps based on the interpretation of wireline data from hydrocarbon exploration holes, industry-acquired seismic reflection data, and the paleoenvironmental interpretation of foraminiferal data derived from well cuttings samples.

Outbuilding of the modem continental shelf-slope margin began during the Early Miocene as the regressive phase of a 1ˢᵗ-order megacycle. Four 2ⁿᵈ-order cycles superimposed on this megacycle have been identified in Taranaki, Wanganui and King Country Basins. The evolution of the Giant Foresets Formation is closely linked to the youngest two megacycles: the Mid Miocene-earliest Pliocene Whangamomona Group/megacycle, and the mid Pliocene-Pleistocene Rangitikei Supergroup/megacycle. The Whangamomona Group includes the Otunui, Mount Messenger, Urenui and Kiore Formations. The continental margin associated with the Whangamomona Group had only limited extent in southern and eastern parts of Taranaki Basin. The Rangitikei Supergroup in Wanganui Basin includes the Tangahoe Mudstone and younger Plio-Pleistocene sediments. The Giant Foresets Formation represents the Rangitikei Supergroup in northern Taranaki Basin.

Revision of the biostratigraphy of four well sections, and integration with biostratigraphic data from other well sections, has highlighted the development in northern Taranaki Basin of a region-wide unconformity between Miocene (Late Tongaporutuan to Late Kapitean) and Pliocene (Early to mid Opoitian) strata, prior to deposition of the Giant Foresets Formation. This is expressed as a paraconformity across much of the northern part of the Western Stable Platform (Ariki Formation), thinner condensed intervals in the Northern Graben, and an erosional unconformity across the Turi Fault Zone. The Ariki Formation is related to at least three important events: (i) the limited extent of progradation of the Whangamomona Group foreset front; (ii) initiation of extension of the Northern Graben; and (iii), the timing of the Tangahoe pulldown in Wanganui Basin. Palinspastic restoration of a complete seismic reflection profile, and backstripping and decompaction of eleven well sections, suggests that paleobathymetric relief may have been locally important in extending the duration of terrigenous sediment starvation.

Six wireline facies have been identified in the Giant Foresets Formation and underlying units. These are: (i) hemipelagic facies; (ii) basin floor fan facies; (iii) slope fan facies; (iv) shelf facies; (v) slumped facies; and (vi) condensed facies. A number of subfacies have also been identified. Construction of a fence diagram using the facies motifs identified in this study has highlighted the distribution of volcaniclastic versus siliciclastic and hemipelagic sedimentation patterns in both time and space in northern Taranaki Basin. The Miocene was dominated by hemipelagic facies interfingering with coarser lithologies sourced predominantly from reworked volcaniclastic material, which travelled some distance into the northwestern region of northern Taranaki Basin. The Plio-Pleistocene Giant Foresets Formation is characterised by a hemipelagic motif, reflecting the dominantly fine-grained nature of the unit, although the formation displays an overall coarsening-upward trend, reflecting increasing proximity to the advancing foreset front and the development of shelf deposits. Localised Pliocene basin floor fans in the Northern Graben (Mangaa Formation) emphasize the role of the graben as a sink for sedimentation during the Opoitian and Waipipian.

Identification and mapping of more than 70 seismic units within the Giant Foresets Formation in northern Taranaki Basin has allowed the post-Miocene sediment distribution patterns to be characterised. Isopach maps and structure contour maps demonstrate the translation of depocentres through time, and illustrate how the sediment distribution pattern associated with the advancing continental margin gradually changed from one of focused sedimentation in the south, and along the axis of the Northern Graben (Mangaa Formation), to a more linear front. Numerous channels and channel systems have been mapped in the Mangapanian to Nukumaruan shelf succession, often preferentially oriented along the axis of the Northern Graben.

The muddy texture of the Giant Foresets Formation is also shown by the seismic characteristics of the formation, with architectural elements and depositional styles reflecting mud- and mixed mud/sand-rich depositional systems. Basin floor (bottomset) facies are characterised by low- relief mounds and/or gull-wing geometries of channel-levee systems, or sub-parallel reflectors, while slope (foreset) facies are dominated by chaotic reflection configurations consistent with slumped deposits or numerous stacked small-scale channel-levee systems on the middle and lower slope.

Much of the shallowing of water depth in northern Taranaki basin occurred during deposition of bottomset facies. Depositional environments changed from mid/lower bathyal during the Late Pliocene, to upper bathyal during the Waipipian and Mangapanian. However, the most rapid aggradation and progradation of the continental margin occurred during the Mangapanian to Late Nukumaruan, with progradational rates as high as 35 km/m.y. recorded. While the coarsest sediment textures are associated with shelf (topset) facies, and the youngest (degradational) foreset units, examination of benthic foraminiferal samples indicate that there was effective transport from the shelf to the base of slope throughout the depositional history of the Giant Foresets Formation.

A dramatic (uphole) decrease in planktic foraminiferal percentage between the Ariki/ Manganui Formations and the Giant Foresets Formation, with a corresponding change in watermass conditions but no dramatic change in water depth, suggests that the progradation of the continental margin during the latest Miocene and Early Pliocene acted to deflect coastal upwelling cells away from northern Taranaki Basin, decreasing available surface water nutrients, and thus reducing the abundance of planktic foraminifera during this time.

Cyclicity within the Giant Foresets Formation is evident on seismic reflection profiles, in wireline motifs, and from paleontological evidence. Sequences may be defined by a particular wireline motif, or set of motifs, the use of seismic reflection configurations to identify components of depositional environments interpreted to represent regressive (RST) and lowstand (LST) sea level conditions, and through the identification of mixed deep water and shallow water benthic foraminiferal assemblages. Basinward of the shelf margin, the highstand systems tract (HST) is often only represented by a bright, high amplitude and laterally continuous reflector that rolls over into shelf deposits. Transgressive (TST) and HST components of a relative sea level cycle cannot be separated from each other on seismic reflection profiles of the shelf deposits of the Giant Foresets Formation. Sequence boundaries often correspond to a bold seismic reflector horizon. A number of discrete high order sequences have been identified, but many of these cannot be consistently correlated between well sections. However, three levels of cyclicity can be established: 2ⁿᵈ-order cycles related to progradation of the Whangamomona Group and Rangitikei Supergroup, 4ᵗʰ-order (400 ka) cycles, and 5ᵗʰ - order (100 ka) cycles (possibly related to glacio-eustatic controls). Sequences are highly asymmetrical, with most of the deposition occurring during lowering and low sea level conditions. Sediment flux is the predominant factor controlling the seismic character of well sections. However, three levels of cyclicity can be established: 2ⁿᵈ-order cycles related to progradation of the Whangamomona Group and Rangitikei Supergroup, 4ᵗʰ-order (400 ka) cycles, and 5ᵗʰ-order (100 ka) cycles (possibly related to glacio-eustatic controls). Sequences are highly asymmetrical, with most of the deposition occurring during lowering and low sea level conditions. Sediment flux is the predominant factor controlling the seismic character of the Late Opoitian to Mangapanian parts of the Giant Foresets Formation, while changes in relative sea level during the Nukumaruan to Castlecliffian increasingly influenced stratal architecture. The shoreline is not considered to have moved basinward of the shelf break during any of the sea level cycles represented in the Giant Foresets Formation, except possibly for a few cycles during the Late Nukumaruan and Castlecliffian.

year: 2003

title: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2017

authors: Hicks, Brendan J.

abstract: The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (tuna, or eels, morihana, or goldfish, and kōura, or freshwater crayfish). In the current study, we present the findings from the eleventh year of sampling (2017) and a summary of previous surveys.
We used the University of Waikato’s 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of 1,110 fish and 3 kōura (18.2 kg in total) from 11 sites on 5 December 2017. The sites comprised 2,909 lineal m and 11,636 m2 in area. Kōura (freshwater crayfish) and 6 fish species were present, with common bully the most abundant species (up to 29.6 fish 100 m⁻² at the site 8, edge habitat). Goldfish (up to 14.2 100 m⁻²) was the next most abundant species, with most goldfish at sites 8 and 11 in and around the side channel. Common smelt were next the most abundant species (up to 11.4 fish 100 m⁻²). Mean density of bullies (7.8 fish 100 m⁻²) was much higher than for smelt (1.69 fish 100 m⁻²). Kōura had a patchy distribution with only 3 individuals were caught at two sites.
Comparing catches over the 11 years of sampling, the mean abundance of common bullies in 2017 was consistent with densities in most post-wall years (after 2007), but lower than in 2007 before wall closure (Newman-Keuls multiple range test, P = 0.034). The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, but low BDD did not correspond with low common bully densities. In 2017, smelt abundance had recovered somewhat from the low catches from 2014 to 2016.
Goldfish biomass increased initially (2009-2010) because of targeted fishing in the side channel (site 11), which has dense macrophytes and offers good habitat for goldfish with no flow. However, the continued rise in goldfish density from 2012 on suggests a real increase in goldfish numbers. In contrast to most previous years, no eels were caught in 2017.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 10 years of post-wall data, and comparisons of means and standard deviations suggest that the number of bullies have been lower since 2008 with the exception of 2015, when bully densities were the same as 2007, i.e., before wall closure. The large number of small juvenile bullies (<30 mm) suggests that recruitment is taking place in the channel, so fluctuating bully abundance is likely to be controlled by factors other than wall closure.

text: Boat electrofishing survey of fish abundance in the Ohau Channel, Rotorua, in 2017 The aim of the survey was to provide on-going monitoring of the fish communities and abundance by boat electrofishing in the Ohau Channel, especially fish species that are taonga to Maori (tuna, or eels, morihana, or goldfish, and kōura, or freshwater crayfish). In the current study, we present the findings from the eleventh year of sampling (2017) and a summary of previous surveys.
We used the University of Waikato’s 4.5 m-long, aluminium-hulled electrofishing boat to catch a total of 1,110 fish and 3 kōura (18.2 kg in total) from 11 sites on 5 December 2017. The sites comprised 2,909 lineal m and 11,636 m2 in area. Kōura (freshwater crayfish) and 6 fish species were present, with common bully the most abundant species (up to 29.6 fish 100 m⁻² at the site 8, edge habitat). Goldfish (up to 14.2 100 m⁻²) was the next most abundant species, with most goldfish at sites 8 and 11 in and around the side channel. Common smelt were next the most abundant species (up to 11.4 fish 100 m⁻²). Mean density of bullies (7.8 fish 100 m⁻²) was much higher than for smelt (1.69 fish 100 m⁻²). Kōura had a patchy distribution with only 3 individuals were caught at two sites.
Comparing catches over the 11 years of sampling, the mean abundance of common bullies in 2017 was consistent with densities in most post-wall years (after 2007), but lower than in 2007 before wall closure (Newman-Keuls multiple range test, P = 0.034). The cause of fluctuating bully abundance is not known, and was not accounted for by changes in water clarity expressed as black disc distance (BDD), water temperature, or water conductivity. Poor water clarity can reduce the efficiency of electrofishing, but low BDD did not correspond with low common bully densities. In 2017, smelt abundance had recovered somewhat from the low catches from 2014 to 2016.
Goldfish biomass increased initially (2009-2010) because of targeted fishing in the side channel (site 11), which has dense macrophytes and offers good habitat for goldfish with no flow. However, the continued rise in goldfish density from 2012 on suggests a real increase in goldfish numbers. In contrast to most previous years, no eels were caught in 2017.
Analysis of fish densities before and after wall closure is hampered by the single data point before closure. However, we now have 10 years of post-wall data, and comparisons of means and standard deviations suggest that the number of bullies have been lower since 2008 with the exception of 2015, when bully densities were the same as 2007, i.e., before wall closure. The large number of small juvenile bullies (<30 mm) suggests that recruitment is taking place in the channel, so fluctuating bully abundance is likely to be controlled by factors other than wall closure.

year: 2018