title: Assisted heat transfer and shaft work targets for increased total site heat integration

authors: Walmsley, Timothy Gordon

abstract: Total Site Heat Integration (TSHI) provides a valuable framework for practical integration of multiple energy users. Previous studies have introduced the idea of utilising process heat recovery pockets to assist TSHI. However, these methods are shown to be effective for only some Total Site (TS) problems. As a result, this paper presents a new method for calculating assisted heat transfer and shaft work targets for an example TS problem. Analysis results show that assisted heat transfer increases TSHI only when a process heat recovery pocket spans the TS Pinch Region. The maximum assisted TSHI can be targeted by comparing each heat recovery pocket to the Site Utility Grand Composite Curve (SUGCC) using background/foreground analysis. Where heat recovery pockets span two steam pressure levels away from the TS Pinch Region (usually above), the example shows the potential for assisted shaft work production. In this case, the source segment of the heat recovery pocket generates steam (e.g. MPS), which replaces steam that would otherwise have been extracted from a steam turbine. The sink segment of the heat recovery pocket consumes lower pressure steam (e.g. LPS), which is extracted from the turbine. If a heat recovery pocket falls outside these two situations (assuming direct inter-process integration is disallowed), the entire pocket should be recovered internal to a process.

text: Assisted heat transfer and shaft work targets for increased total site heat integration Total Site Heat Integration (TSHI) provides a valuable framework for practical integration of multiple energy users. Previous studies have introduced the idea of utilising process heat recovery pockets to assist TSHI. However, these methods are shown to be effective for only some Total Site (TS) problems. As a result, this paper presents a new method for calculating assisted heat transfer and shaft work targets for an example TS problem. Analysis results show that assisted heat transfer increases TSHI only when a process heat recovery pocket spans the TS Pinch Region. The maximum assisted TSHI can be targeted by comparing each heat recovery pocket to the Site Utility Grand Composite Curve (SUGCC) using background/foreground analysis. Where heat recovery pockets span two steam pressure levels away from the TS Pinch Region (usually above), the example shows the potential for assisted shaft work production. In this case, the source segment of the heat recovery pocket generates steam (e.g. MPS), which replaces steam that would otherwise have been extracted from a steam turbine. The sink segment of the heat recovery pocket consumes lower pressure steam (e.g. LPS), which is extracted from the turbine. If a heat recovery pocket falls outside these two situations (assuming direct inter-process integration is disallowed), the entire pocket should be recovered internal to a process.

year: 2016

title: Behavioural interactions between black mudfish (Neochanna diversus Stokell, 1949: Galaxiidae) and mosquitofish (Gambusia affinis Baird & Girard, 1854)

authors: Barrier, R.F.G.

subjects: mudfish

abstract: The behavior of black mudfish (Neochanna diversus Stokell, 1949: Galaxiidae) and mosquitofish (Gambusia affinis Baird & Girard, 1854: Poeciliidae) was investigated in laboratory tanks. Black mudfish are indigenous to northern New Zealand, and mosquitofish are introduced; both species are sympatric in wetlands in the Waikato region. By comparing position, feeding rates and aggressive behavior of both species, we found that black mudfish were increasingly able to compete with mosquitofish as they grew from fry to adults. Mosquitofish were more aggressive towards mudfish fry and juveniles than were these two life stages towards mosquitofish, but adult mudfish were aggressive towards mosquitofish. Both small (18–24 mm total length (TL)) and large mosquitofish (25–36 mm TL) showed high aggression towards mudfish fry (13–18 mm TL), and fry were eaten by large mosquitofish. However, 3 interspecific differences appear to allow coexistence of these two species. Firstly, mudfish reproduce in winter, whereas mosquitofish reproduce in summer, resulting in mudfish fry being present when mosquitofish are at their lowest abundance. Secondly, mudfish can survive in seasonally dry habitats by aestivation, while mosquitofish cannot. Thirdly, adult black mudfish are nocturnal, whereas mosquitofish are primarily diurnal.

text: Behavioural interactions between black mudfish (Neochanna diversus Stokell, 1949: Galaxiidae) and mosquitofish (Gambusia affinis Baird & Girard, 1854) The behavior of black mudfish (Neochanna diversus Stokell, 1949: Galaxiidae) and mosquitofish (Gambusia affinis Baird & Girard, 1854: Poeciliidae) was investigated in laboratory tanks. Black mudfish are indigenous to northern New Zealand, and mosquitofish are introduced; both species are sympatric in wetlands in the Waikato region. By comparing position, feeding rates and aggressive behavior of both species, we found that black mudfish were increasingly able to compete with mosquitofish as they grew from fry to adults. Mosquitofish were more aggressive towards mudfish fry and juveniles than were these two life stages towards mosquitofish, but adult mudfish were aggressive towards mosquitofish. Both small (18–24 mm total length (TL)) and large mosquitofish (25–36 mm TL) showed high aggression towards mudfish fry (13–18 mm TL), and fry were eaten by large mosquitofish. However, 3 interspecific differences appear to allow coexistence of these two species. Firstly, mudfish reproduce in winter, whereas mosquitofish reproduce in summer, resulting in mudfish fry being present when mosquitofish are at their lowest abundance. Secondly, mudfish can survive in seasonally dry habitats by aestivation, while mosquitofish cannot. Thirdly, adult black mudfish are nocturnal, whereas mosquitofish are primarily diurnal.

year: 1994

title: Aroha

authors: Maxwell, Te Kahautu

abstract: Waita Tira (choral), Lyrics composed by Te Kahautu Maxwell and Performed by Ōpotoki Mai Tawhiti (Kapa Haka group)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura, Hau Te Kura
Mōteatea: Te Ao o Te Pārerā
Waiata ā Ringa: E pā to reo, Te Matatini, Herewini Parata
Poi: E ia e ia
Haka: Te Kōtiritiri, Te Kōtaratara
Whakawātea: Ōranga Tōiti, tōnui kōrero

text: Aroha Waita Tira (choral), Lyrics composed by Te Kahautu Maxwell and Performed by Ōpotoki Mai Tawhiti (Kapa Haka group)

Waiata ā Tira: Aroha
Whakaeke: Pinepine Te Kura, Hau Te Kura
Mōteatea: Te Ao o Te Pārerā
Waiata ā Ringa: E pā to reo, Te Matatini, Herewini Parata
Poi: E ia e ia
Haka: Te Kōtiritiri, Te Kōtaratara
Whakawātea: Ōranga Tōiti, tōnui kōrero

year: 2023-02-22