title: Hybrid Solid-State Hydrogen Storage Materials

authors: Benge, Kathryn Ruth

subjects: Ammonia Borane

abstract: This thesis investigates the chemistry of ammonia borane (NH₃BH₃) relevant to the development of hydrogen storage systems for vehicular applications.
Because of its high hydrogen content and low molecular weight ammonia borane has the potential to meet stringent gravimetric hydrogen storage targets of >9 wt%. Two of the three moles of H₂ in ammonia borane can be released under relatively mild conditions, with the highest gravimetric yield obtained in the solid-state. However, ammonia borane does not deliver sufficient H₂ at practical temperatures and the products formed upon H₂ loss are not amenable to regeneration back to the parent compound.
The literature synthesis of ammonia borane was modified to facilitate large scale synthesis, and the deuterated analogues ND₃BH₃ and NH₃BD₃ were prepared for the purpose of mechanistic studies.
The effect of lithium amide on the kinetics of dehydrogenation of ammonia borane was assessed by means of solid-state reaction in a series of specific molar ratios. Upon mixing lithium amide and ammonia borane, an exothermic reaction ensued resulting in the formation of a weakly bound adduct with an H₂N...BH₃-NH₃ environment. Thermal decomposition at or above temperatures of 50◦C of this phase was shown to liberate >9 wt% H₂. The mechanism of hydrogen evolution was investigated by means of reacting lithium amide and deuterated ammonia borane isotopologues, followed by analysis of the isotopic composition of evolved gaseous products by mass spectrometry. From these results, an intermolecular multi-step reaction mechanism was proposed, with the rates of the first stage strongly dependent on the concentration of lithium amide present. Compounds exhibiting a BN₃ environment (identi-fied by means of solid-state ¹¹B NMR spectroscopy) were formed during the first stage, and subsequently cross link to form a non-volatile solid. Further heating of this non-volatile solid phase ultimately resulted in the formation of crystalline Li₃BN₂ - identified by means of powder X-ray diffractometry.
This compound has been identified as a potential hydrogen storage material due to its lightweight and theoretically high hydrogen content. It may also be amenable to hydrogen re-absorption.
The LiNH₂/CH₃NH₂BH₃ system was also investigated. Thermal decomposition occurred through the same mechanism described for the LiNH₂/NH₃BH₃ system to theoretically evolve >8 wt% hydrogen. The gases evolved on thermal decomposition were predominantly H₂ with traces of methane detected by mass spectrometry.

text: Hybrid Solid-State Hydrogen Storage Materials This thesis investigates the chemistry of ammonia borane (NH₃BH₃) relevant to the development of hydrogen storage systems for vehicular applications.
Because of its high hydrogen content and low molecular weight ammonia borane has the potential to meet stringent gravimetric hydrogen storage targets of >9 wt%. Two of the three moles of H₂ in ammonia borane can be released under relatively mild conditions, with the highest gravimetric yield obtained in the solid-state. However, ammonia borane does not deliver sufficient H₂ at practical temperatures and the products formed upon H₂ loss are not amenable to regeneration back to the parent compound.
The literature synthesis of ammonia borane was modified to facilitate large scale synthesis, and the deuterated analogues ND₃BH₃ and NH₃BD₃ were prepared for the purpose of mechanistic studies.
The effect of lithium amide on the kinetics of dehydrogenation of ammonia borane was assessed by means of solid-state reaction in a series of specific molar ratios. Upon mixing lithium amide and ammonia borane, an exothermic reaction ensued resulting in the formation of a weakly bound adduct with an H₂N...BH₃-NH₃ environment. Thermal decomposition at or above temperatures of 50◦C of this phase was shown to liberate >9 wt% H₂. The mechanism of hydrogen evolution was investigated by means of reacting lithium amide and deuterated ammonia borane isotopologues, followed by analysis of the isotopic composition of evolved gaseous products by mass spectrometry. From these results, an intermolecular multi-step reaction mechanism was proposed, with the rates of the first stage strongly dependent on the concentration of lithium amide present. Compounds exhibiting a BN₃ environment (identi-fied by means of solid-state ¹¹B NMR spectroscopy) were formed during the first stage, and subsequently cross link to form a non-volatile solid. Further heating of this non-volatile solid phase ultimately resulted in the formation of crystalline Li₃BN₂ - identified by means of powder X-ray diffractometry.
This compound has been identified as a potential hydrogen storage material due to its lightweight and theoretically high hydrogen content. It may also be amenable to hydrogen re-absorption.
The LiNH₂/CH₃NH₂BH₃ system was also investigated. Thermal decomposition occurred through the same mechanism described for the LiNH₂/NH₃BH₃ system to theoretically evolve >8 wt% hydrogen. The gases evolved on thermal decomposition were predominantly H₂ with traces of methane detected by mass spectrometry.

year: 2008

title: Drugs and driving in New Zealand: An approach to THC culpability

authors: Troncoso Vergara, Carolina

subjects: drugs and driving

abstract: For years statistical analysis has been applied to different areas of the natural and applied sciences to determine the degree of confidence that can be placed in research results.

This work is a good example of how statistics can be applied to toxicology to enable conclusions and inferences to be made about important areas of interest such as the drugs and driving situation in New Zealand.

Two thousand uninjured drivers (Study 1) who had provided an evidential blood alcohol sample, were also tested for cannabis, methamphetamine, benzodiazepines and morphine to determine the incidence of drug use by drinking drivers.
 
To determine the proportion of drivers killed in car crashes who had used drugs and/or alcohol, two hundred and twenty nine fatally injured drivers (Study 2) were tested for alcohol, cannabis, methamphetamine, morphine, benzodiazepines and neutral and basic medicinal drugs that might have an effect on driving performance. 

Alcohol, cannabis and their combination were found to be the most prevalent drugs used by drivers. 

The analytical methodologies used were developed and validated by the Institute of Environmental Science and Research Ltd., where this work was carried out. These techniques involved liquid-liquid and liquid-solid extractions, immunoassays and chromatographic techniques for screening and confirmation assays. The statistical analysis of the results was done under the supervision of the Institute's biostatistician.

An approach to cannabis culpability, intended to elucidate the role of this drug in car crashes, was applied to the Study 2 results. The number of samples collected during one year of research was not sufficient to enable statistically robust conclusions to be drawn.

Cannabis use is illegal in New Zealand but drugs (different to alcohol) are not regularly tested at the roadside. This work as part of a cross-departmental project titled  Drinking and drugged driver control: delineating the problem  is expected to support the establishment of strategies designed to reduce the road toll and possibly include the screening of non-alcohol drugs in serious and fatally injured drivers.

text: Drugs and driving in New Zealand: An approach to THC culpability For years statistical analysis has been applied to different areas of the natural and applied sciences to determine the degree of confidence that can be placed in research results.

This work is a good example of how statistics can be applied to toxicology to enable conclusions and inferences to be made about important areas of interest such as the drugs and driving situation in New Zealand.

Two thousand uninjured drivers (Study 1) who had provided an evidential blood alcohol sample, were also tested for cannabis, methamphetamine, benzodiazepines and morphine to determine the incidence of drug use by drinking drivers.
 
To determine the proportion of drivers killed in car crashes who had used drugs and/or alcohol, two hundred and twenty nine fatally injured drivers (Study 2) were tested for alcohol, cannabis, methamphetamine, morphine, benzodiazepines and neutral and basic medicinal drugs that might have an effect on driving performance. 

Alcohol, cannabis and their combination were found to be the most prevalent drugs used by drivers. 

The analytical methodologies used were developed and validated by the Institute of Environmental Science and Research Ltd., where this work was carried out. These techniques involved liquid-liquid and liquid-solid extractions, immunoassays and chromatographic techniques for screening and confirmation assays. The statistical analysis of the results was done under the supervision of the Institute's biostatistician.

An approach to cannabis culpability, intended to elucidate the role of this drug in car crashes, was applied to the Study 2 results. The number of samples collected during one year of research was not sufficient to enable statistically robust conclusions to be drawn.

Cannabis use is illegal in New Zealand but drugs (different to alcohol) are not regularly tested at the roadside. This work as part of a cross-departmental project titled  Drinking and drugged driver control: delineating the problem  is expected to support the establishment of strategies designed to reduce the road toll and possibly include the screening of non-alcohol drugs in serious and fatally injured drivers.

year: 2006

title: Kaupapa Māori research- Some Kaupapa Māori principles

authors: Smith, Linda Tuhiwai

abstract: This paper was first presented at a conference of Māori academic staff at Massey University in 1996. It predates the publication of Decolonising Methodologies in 1998. You will note that since this paper was first presented our understandings and experiences in using Kaupapa Māori have deepened and we have significant capacity in Kaupapa Māori research. In 1996 there were many topics we could not imagine in depth as we had not completed the work to realise the potential of Kaupapa Māori. Also, our thinking was tentative and we were searching for the pathways to research that made sense in Māori ways. In looking back on the paper I can see my own naïve explorations into ideas that I thought were important. I have resisted the urge to rewrite this paper entirely as I think it stands as a good historical moment of where we were and where we are now. It needs to be read in the context of the 1990s.

text: Kaupapa Māori research- Some Kaupapa Māori principles This paper was first presented at a conference of Māori academic staff at Massey University in 1996. It predates the publication of Decolonising Methodologies in 1998. You will note that since this paper was first presented our understandings and experiences in using Kaupapa Māori have deepened and we have significant capacity in Kaupapa Māori research. In 1996 there were many topics we could not imagine in depth as we had not completed the work to realise the potential of Kaupapa Māori. Also, our thinking was tentative and we were searching for the pathways to research that made sense in Māori ways. In looking back on the paper I can see my own naïve explorations into ideas that I thought were important. I have resisted the urge to rewrite this paper entirely as I think it stands as a good historical moment of where we were and where we are now. It needs to be read in the context of the 1990s.

year: 2015