title: Supercapacitor assisted low dropout regulators (SCALDO) with reduced switches: A new approach to high efficiency VRM designs

authors: Kularatna, Nihal

subjects: VRM

abstract: Supercapacitor assisted low dropout (SCALDO) regulator is a new approach to develop high efficiency DC-DC converters with supercapacitors used for energy recovery. One limitation in these topologies is that in some configurations a large number of low-speed switches are required. If the SCALDO technique is adapted to build voltage regulator modules (VRM), it is necessary to reduce number of switches combined with a high current capable LDO. A new topology-variation with less number of switches can be achieved by reconfiguring the original SCALDO and adding an extra LDO to the circuit. The paper presents a summary of some preliminary work, and experimental results for a 2.5V proof of concept-prototype.

text: Supercapacitor assisted low dropout regulators (SCALDO) with reduced switches: A new approach to high efficiency VRM designs Supercapacitor assisted low dropout (SCALDO) regulator is a new approach to develop high efficiency DC-DC converters with supercapacitors used for energy recovery. One limitation in these topologies is that in some configurations a large number of low-speed switches are required. If the SCALDO technique is adapted to build voltage regulator modules (VRM), it is necessary to reduce number of switches combined with a high current capable LDO. A new topology-variation with less number of switches can be achieved by reconfiguring the original SCALDO and adding an extra LDO to the circuit. The paper presents a summary of some preliminary work, and experimental results for a 2.5V proof of concept-prototype.

year: 2013

title: Synthesis and Characterisation of Cycloaurated Gold(III) Complexes with Bidentate (O,O), (N,S) and (S,S) Chelating Ligands

authors: Smith, Tiffany Sharee

subjects: Cycloaurated Gold(III) Complexes

abstract: The reaction of C,N-coordinated gold(III) dihalides; BpAuCl₂ (Bp = 2 benzylpyridyl), AnpAuCl₂ (Anp = 2 anilinopyridyl) and TypAuCl₂ (Typ = 2 tolylpyridyl) with catecholate ligands in hot methanol and trimethylamine produced metallacycles with structural isomers of the general formula (C,N)Au{O,O}. Similarly, BpAuCl₂ and AnpAuCl₂ were reacted with thiourea ligands to form complexes giving high yield and good purity with the general formula (C,N)Au{PhNCSNR₂}+, by means of the addition of BPh₄- for precipitation. X-ray crystal structures of the compounds [AnpAu{PhNCSNMe₂}]BPh₄ and [AnpAu{PhNCSNCy₂}]BPh₄ confirmed the coordination of the thiourea to the gold centre through the N and S atoms. In both cases the geometry around the gold atom is square-planar with complex [AnpAu{PhNCSNCy₂}]BPh₄ showing a slightly more puckered conformation than [AnpAu{PhNCSNMe₂}]BPh₄ due to the sterically bulky cyclohexyl groups attached. Some thiourea derivatives were tested against P388 murine leukaemia cells with complex [AnpAu{PhNCSNHPh}]BPh₄ showing promising anti-tumour activity.

When thiourea ligands were replaced by dithiophosphinate and dithiophosphate ligands the reaction proceeded at room temperature without the need for the presence of a base. Relatively low yields of impure metallacycles with the general formula (C,N)Au{S₂PR₂}+ were obtained on the addition of BPh₄- or BF₄-. Attempts to improve purity by varying batches of starting materials, anion and solvents used were unsuccessful. X-ray crystal data from a single crystal of [(C,N)Au{S₂PPh₂}]BPh₄ shows the reduction of gold(III) to gold(I) forming a known polymeric gold(I) dithiophosphinate complex. In order to extend this study the synthesis of complexes with the general formula R₂PS₂AuCl₂ was attempted, but no new compounds were characterised.

Where possible, all new compounds reported in this thesis were characterised by ES-MS, IR, NMR, melting point and micro-elemental analysis.

text: Synthesis and Characterisation of Cycloaurated Gold(III) Complexes with Bidentate (O,O), (N,S) and (S,S) Chelating Ligands The reaction of C,N-coordinated gold(III) dihalides; BpAuCl₂ (Bp = 2 benzylpyridyl), AnpAuCl₂ (Anp = 2 anilinopyridyl) and TypAuCl₂ (Typ = 2 tolylpyridyl) with catecholate ligands in hot methanol and trimethylamine produced metallacycles with structural isomers of the general formula (C,N)Au{O,O}. Similarly, BpAuCl₂ and AnpAuCl₂ were reacted with thiourea ligands to form complexes giving high yield and good purity with the general formula (C,N)Au{PhNCSNR₂}+, by means of the addition of BPh₄- for precipitation. X-ray crystal structures of the compounds [AnpAu{PhNCSNMe₂}]BPh₄ and [AnpAu{PhNCSNCy₂}]BPh₄ confirmed the coordination of the thiourea to the gold centre through the N and S atoms. In both cases the geometry around the gold atom is square-planar with complex [AnpAu{PhNCSNCy₂}]BPh₄ showing a slightly more puckered conformation than [AnpAu{PhNCSNMe₂}]BPh₄ due to the sterically bulky cyclohexyl groups attached. Some thiourea derivatives were tested against P388 murine leukaemia cells with complex [AnpAu{PhNCSNHPh}]BPh₄ showing promising anti-tumour activity.

When thiourea ligands were replaced by dithiophosphinate and dithiophosphate ligands the reaction proceeded at room temperature without the need for the presence of a base. Relatively low yields of impure metallacycles with the general formula (C,N)Au{S₂PR₂}+ were obtained on the addition of BPh₄- or BF₄-. Attempts to improve purity by varying batches of starting materials, anion and solvents used were unsuccessful. X-ray crystal data from a single crystal of [(C,N)Au{S₂PPh₂}]BPh₄ shows the reduction of gold(III) to gold(I) forming a known polymeric gold(I) dithiophosphinate complex. In order to extend this study the synthesis of complexes with the general formula R₂PS₂AuCl₂ was attempted, but no new compounds were characterised.

Where possible, all new compounds reported in this thesis were characterised by ES-MS, IR, NMR, melting point and micro-elemental analysis.

year: 2012

title: Tūrangawaewae mō te Kīngitanga

authors: Takerei, Mamae Rangiaroha Tuānewa

subjects: Tūrangawaewae

abstract: Tūrangawaewae is an iconic marae located at the heart of the Kīngitanga. Established by Te Pūea Hērangi and other whānau, this marae has come to represent the struggles, successes and history of the Kīngitanga movement. Tūrangawaewae is therefore the embodiment of the Kīngitanga and the people of Waikato.
From very humble beginnings, and forged on the tireless efforts of Te Pūea and her followers, this marae has hosted world leaders, monarchs and aristocracy from across the world. All have come to Tūrangawaewae to forge relationships with the Kīngitanga, with Māori and with the New Zealand government. It has become a hallowed place when histories are shared and futures are created.
This thesis looks at how Tūrangawaewae encapsulates the Kīngitanga and all that it means. It explores this history of its establishment and highlight the central figures and the motivations behind the building of this marae and complex. In addition, this thesis will show how the different building and features of the marae showcase the ideology of the Kīngitanga movement and its leaders. Based on a traditional approach to Waikato knowledge, and founded on firsthand experience, this thesis reveals an insides perspective of the kīngitanga, the people, various events and the marae of Tūrangawaewae.

text: Tūrangawaewae mō te Kīngitanga Tūrangawaewae is an iconic marae located at the heart of the Kīngitanga. Established by Te Pūea Hērangi and other whānau, this marae has come to represent the struggles, successes and history of the Kīngitanga movement. Tūrangawaewae is therefore the embodiment of the Kīngitanga and the people of Waikato.
From very humble beginnings, and forged on the tireless efforts of Te Pūea and her followers, this marae has hosted world leaders, monarchs and aristocracy from across the world. All have come to Tūrangawaewae to forge relationships with the Kīngitanga, with Māori and with the New Zealand government. It has become a hallowed place when histories are shared and futures are created.
This thesis looks at how Tūrangawaewae encapsulates the Kīngitanga and all that it means. It explores this history of its establishment and highlight the central figures and the motivations behind the building of this marae and complex. In addition, this thesis will show how the different building and features of the marae showcase the ideology of the Kīngitanga movement and its leaders. Based on a traditional approach to Waikato knowledge, and founded on firsthand experience, this thesis reveals an insides perspective of the kīngitanga, the people, various events and the marae of Tūrangawaewae.

year: 2019