To see the other types of publications on this topic, follow the link: Acacia Effect of temperature on.
Dissertations / Theses on the topic 'Acacia Effect of temperature on'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Acacia Effect of temperature on.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Cheng, Ling-Lan. "A laboratory behavioral assessment on predatory potential of the green lacewing Mallada basalis walker (Neuroptera: chrysopidae) on two species of papaya pest mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor) (Acari: tetranychidae)." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/405.
Full text
2
Abukhashim, Nagia K. "Some effects of temperature on the biology of Tetranychus urticae (Koch)(Acarina)." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295532.
Full text
3
Creel, Sarah Frances. "Effect of acacia gum on bare root nursery crops and in cutting propagation." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/CREEL_SARAH_14.pdf.
Full text
4
Schuch, Ursula K., Jack Kelly, and Frank Stryker. "Effect of Planting Hole Size and Amendments on Growth and Establishment of Acacia farnesiana." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/216554.
Full textAbstract:
The objective of this project was to determine whether the size of planting holes and the addition of organic material in the backfill is beneficial for plant establishment and growth during the early years. Acacia farnesiana were transplanted from containers into a permanent landscape using four methods: large planting hole with or without amendments or a small planting hole with or without amendments. The study was repeated on two sites. Three years following transplanting, plant growth such as height and caliper were not affected by the planting hole size or amendments, but differed significantly between sites. Plants that received more irrigation and were planted in a less rocky soil had greater caliper and were taller than those supplied with less irrigation and planted on a more rocky soil. Visual observations one and three years after transplanting indicate that trees that were amended with compost in the backfill had the highest incidence of leaning trunks and sinking crowns (20% of trees in study or 37% of those receiving amendments) while of those trees that were not amended only one tree (3%) was leaning three years after transplanting. Hole size at transplanting had no significant effect on leaning or sinking three years after transplanting. These results confirm earlier research across the country that 33% to 50% organic amendment in backfill compared to native soil at transplanting is not beneficial for native trees, but increases the risk of leaning or sinking.
5
El, Mghadmi Z. Y. "Effect of environmental stresses and growing medium amendment with 'Zander' on growth of Acacia saligna under saline conditions." Thesis, Coventry University, 2011. http://curve.coventry.ac.uk/open/items/5727ee90-f827-485e-93d9-94a9b5456f43/1.
Full textAbstract:
In Libya salinization of land and ground water is a key problem. A. saligna is one species that offers potential for growth under these conditions. Experiments were undertaken to accelerate the germination of Acacia seeds, and various pre-treatment methods were assayed. Boiling water treatment, mechanical scarification and acid improved germination and germination rate. Sowing A. saligna seeds at 30 mm depth gave greatest seedling growth from large and medium seeds whereas 20 mm was more suitable for small seeds. This study aimed to improve the establishment of Acacia saligna irrigated with saline water, plants were grown for seven weeks under greenhouse or field conditions in (Libya) either sand or soil salinized with varying applications of NaCl. Irrigation with NaCl significantly decreased plant survival and growth and concentration of Ca, Na, K, Fe and P ions in plants with 0.5 M or 1.0 M NaCl. The experiments were repeated using a naturally occurring soil amendment called ‘Zander’. Seeds of A. saligna were grown for seven weeks in both greenhouse and field trials as before but with the addition of Zander and NaCl. Zander improved plant survival and growth with salinity and increased the elements in plants (Ca, Na, K, Fe and P). Field experiments were conducted to assess the effects of saline irrigation with 1.0 M NaCl and extra water added to 0% or 10% Zander on survival and growth, consequently, seedling growth significantly decreased with increase in soil salinity. Survival and growth increased with increase in extra water. The additional irrigation water caused an increase in the uptake of Ca++ and increased the Ca++/Na+ and K+/Na+ ratio. Zander did not appear to reduce net uptake of Na+ and its transport to shoot tissues. Mg++, P, K+ and Ca++ content significantly decreased in plants in response to salinity. Possible mechanisms to avoid Na+ toxicity in A. saligna in response to salinity included increasing the supply of Ca++. Extra Ca++ applied into the medium with and without salt increased survival and growth even in the absence of Zander. Calcium increased uptake of Ca++ and increased Ca++/Na+ and K+/Na+ ratio.
6
Marsh, M. G. "The effect of a temperature gradient on high temperature fretting wear." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267625.
Full text
7
Lufitha, Mundel. "Effect of substrate temperature on coating adhesion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58842.pdf.
Full text
8
Phillips, Lisa Elaine. "The effect of low temperature on Salmonella." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286534.
Full text
9
Mitchell, Angela. "The effect of temperature on starch synthesis." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243060.
Full text
10
Prasad, Renee Priya. "The effect of rearing temperature on performance of Trichogramma sibericum at ambient temperature." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51451.pdf.
Full text
11
au, A. Jayasekera@murdoch edu, and Arunodini Uthpalawanna Jayasekera. "Interactions between Phytophthora cinnamomiand Acacia pulchella: consequences on ecology and epidemiology of the pathogen." Murdoch University, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20061129.134500.
Full textAbstract:
Phytophthora cinnamomi is an important pathogen of many plant species in natural ecosystems and horticulture industries around the world. In Western Australia, a high proportion of native plant species are susceptible to P. cinnamomi attack. Acacia pulchella, a resistant legume species native to Western Australia has been considered as a potential biological control tool against P. cinnamomi. To develop effective control methods, it is important to understand the interactions between the control agent and the different life forms of the pathogen. In this thesis the interactions are investigated between P. cinnamomi and varieties of A. pulchella which occur in jarrah (Eucalyptus marginata) forest and sand plain ecosystems.
The soil inoculum of P. cinnamomi was compared under the potted plants of the three common varieties of A. pulchella, var. pulchella, var. glaberrima and var. goadbyi. These were grown in infected jarrah forest soil in the glasshouse and in vitro in a sterilised soil-less mix aseptically. Acacia urophylla (a species non suppressive towards P. cinnamomi) was also included as a control. An isolate of the most commonly found clonal lineage of P. cinnamomi in the jarrah forest, A2 type 1 was selected for use in experiments after testing showed it reliably produced zoospores and chlamydospores both axenically and in non-sterile conditions, in comparison to several other isolates. The lowest survival of P. cinnamomi inoculum was found under A. pulchella var. goadbyi plants grown both in non sterile soil and in aseptic soil-less mix.
All the life forms of P. cinnamomi were affected by A. pulchella (Chapters 2, 3, 4 and 5). The soil leachates from potted plants of A. pulchella var. goadbyi reduced sporangial production (Chapter 2) and caused cytoplasm collapse of chlamydospores (Chapter 3). The confirmation was obtained that soil under A. pulchella was inhibitory to sporangial stage of P. cinnamomi and new evidence was obtained on chlamydospore inactivation. Cytoplasm collapse in the chlamydospores was observed both for chlamydospores on mycelial discs on Mira cloth exposed to the soil leachate and within infected roots buried in soils under the three varieties of A. pulchella plants. The effect was strongest under the plants of A. pulchella var. goadbyi and indicated that the chlamydospores of P. cinnamomi are unlikely to act as persistent structures under A. pulchella var. goadbyi plants.
In Chapter 4, bioassays were conducted with axenically produced mycelia, chlamydospores and zoospores to test the inhibitory effect of the root exudates collected from aseptically grown A. pulchella var. goadbyi plants. The zoospores of the same isolate used in the soil leachate tests were immobilised (became sluggish and encysted) within one to two minutes. When incubated for 24 h, zoospores predominantly clumped and germ tubes were observed only from the clumped ones. Chlamydospores produced by four isolates of the common A2 type 1 strain and the only one A2 type 2 strain available at the time were tested. A higher percentage of chlamydospores collapsed and a very low percentage germinated after 24 h. Chlamydospores of all the A2 type 1 isolates were inhibited by the root exudates whilst the A2 type 2 isolate remained viable. The findings showed that the suppressive effect must be due at least in part to substances exuded by the A. pulchella plants. However, it appeared that the A2 type 1 isolates were more vulnerable to this effect than the single A2 type 2 isolate.
In Chapter 5, the effect of season on sporangial suppression of P. cinnamomi was shown using field soils collected from three jarrah forest soil vegetation types and a Banksia woodland on Bassendean sand, collected in winter and summer. The effect of age of A. pulchella plants was demonstrated using the soils collected from rehabilitated bauxite mine pits. In all the locations soils were collected under A. pulchella plants and 5 m away from the nearest A. pulchella. An effect of soil type was evident as whilst the soil leachates made from the three lateritic jarrah forest soil types where A. pulchella is common in the understorey were suppressive to the sporangial stage of P. cinnamomi, this effect was not evident in the Bassendean sand under A. pulchella. A. pulchella soils collected in winter were less suppressive towards sporangial production than soils collected in summer. An effect of plant age was demonstrated as soil leachates from four year-old A. pulchella stands in rehabilitated bauxite mine sites were more suppressive for sporangia than leachates from one year-old stands.
Further information on the behaviour of the pathogen in soil and in potting mix with and without A. pulchella was obtained by infecting lupin radicles with an isolate of each A2 type, 1 and 2 strains of P. cinnamomi and burying them in the soil under the three varieties of A. pulchella plants. After a week, the chlamydospores were mostly collapsed and hyphae deteriorated. Oospores were observed and in significant numbers under the potted plants of A. pulchella var. glaberrima.
Isolates of all three clonal lineages of P. cinnamomi found in Australian soil were tested for the ability to produce oospores. Two isolates of the A1 and A2 type 2 and three isolates of the common A2 type 1 were screened. The two isozyme types of the A2 clonal lineage isolated in Australia varied in ability to self and produce oospores in planta in several soils from the jarrah forest. The isozyme type 2 of the A2 clonal lineage of P. cinnamomi produced oospores under these experimental conditions. This stimulation was not effective for most of the tested isolates of the A2 type 1 and the A1 clonal lineage. The in planta oospores were viable but dormant and the oogonial-antheridial associations were amphigynous both in vitro and in vivo. For the first time it was established that, the stimulus for selfing and oospore formation in the A2 type 2 of P. cinnamomi is available in some jarrah forest soils, with and without A. pulchella and also in the potting mix used. This raises important questions for the management of the pathogen.
Several factors were identified as potential stimuli for selfing. Among them, soil nutrient levels and essentially enhanced sulphur presence were found important. Temperature also played a key role. Oospores were produced abundantly at 21 25 ºC but not over 28 ºC.
The biology of P. cinnamomi has been studied for several decades but some important aspects remain un-researched. This thesis pioneers research into the in planta selfing aspect of the pathogen in soil. It also improved the understanding of the interactions between P. cinnamomi and A. pulchella which to some extent supports use of A. pulchella as a biological control tool against P. cinnamomi. However, attention is drawn to the natural mechanisms of this complex pathogen to survive in planta by producing oospores, the most persistent form of its life cycle.
12
Griškevičius, Mečislavas. "High Temperature Effect On Resistance Of Timber Structures." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20101119_134602-29128.
Full textAbstract:
The present dissertation and its main subjects inquires into the pine and oak timber strength property changes-temperature relations. It also explores the behaviour of slender timber elements in axial compression at higher temperatures; and the comparative analysis of obtained results.
The work seeks to accomplish the following major tasks: to obtain test data about the influence of high temperature on the properties of different natural – pine and oak – timber; to investigate the behaviour of slender timber elements under axial compression exposed to fire. Taking into account the investigated real fire effect to correct accordingly the existing in LST EN 1995-1-2 procedure for the fire resistance calculation of timber slender elements in compression.
The dissertation consists of an introduction, five chapters, general conclusions, a list of references, a list of author’s publications on the dissertation subject, and 2 Annexes.
Chapter 1 provides a literature review. It focuses on the publications inquiring into the loss of strength properties by timber at higher temperatures, the fire resistance of timber structures in compression. The chapter ends with the formulation of conclusions and the adjustment of research tasks.
Chapter 2 offers the methodology of the research on strength properties of timber at higher temperatures, and the schemes of the developed testing equipment.
Chapter 3 presents the procedure of the research on the behaviour of slender timber elements... [to full text]<br>Disertacijoje nagrinėjami pušinės ir ąžuolinės medienos stipruminių savybių pokyčių temperatūriniai sąryšiai bei medinių centriškai gniuždomų liaunų elementų elgsena veikiant aukštesnėms temperatūroms. Pagrindiniai tyrimo objektai yra Lietuvos spygliuočių ir lapuočių medienos savybių pokyčiai didėjant temperatūrai ir centriškai gniuždomų liaunų medinių elementų elgsenos veikiant kaitrai eksperimentiniai tyrimai bei rezultatų lyginamoji analizė.
Darbe spręsti tokie pagrindiniai uždaviniai: gauti eksperimentinius duomenis apie aukštos temperatūros poveikį skirtingos natūralios – pušinės ir ąžuolinės – medienos savybėms, atlikti centriškai gniuždomų liaunų medinių elementų elgsenos ugnyje tyrimus. Atsižvelgiant į tyrinėtą tikrovišką gaisro poveikį patikslinti esamą EN 1995-1-2 medinių liaunų gniuždomų elementų atsparumo ugniai skaičiavimo metodiką.
Disertaciją sudaro įvadas, penki skyriai, bendrosios išvados, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir du priedai.
Pirmasis skyrius skirtas literatūros apžvalgai. Jame pateikta darbų, kuriuose nagrinėjamas aukštesnės temperatūros veikiamos medienos, stipruminių savybių mažėjimas ir kuriuose pateikiami gaisro sąlygomis gniuždomų medinių elementų laikomosios galios tyrimų rezultatai. Pabaigoje formuluotos išvados ir disertacijos tikslai ir uždaviniai.
Antrajame skyriuje pateikta medienos stipruminių savybių aukštesnėse temperatūrose tyrimo metodika ir sukurtų nestandartinių bandymo įrenginių schemos... [toliau žr. visą tekstą]
13
Kakireddy, Veera Raghava R. "Effect of temperature on copper chemical mechanical planarization." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001973.
Full text
14
Takahashi, Junji 1951. "Effect of high temperature on lettuce seed development." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276828.
Full textAbstract:
More vegetable seeds are needed for developing countries to produce more vegetables. However, high temperature in these areas limits vegetable seed production. Leaf lettuce (Lactuca sativa L.) was grown in growth chambers at 21°C and exposed to different temperatures (28, 35, 38 and 42°C) for different exposure times (1, 4 and 7 hours) when flowers were at seven stages of development near anthesis.
15
Huang, Yan, and 黃燕. "Temperature dependent hall effect: studies ofGaN on sapphire." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42577068.
Full text
16
Harvey, Roy Edward. "The effect of high temperature on yeast fermentations." Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/1000.
Full text
17
McGinnity, Frank A. "The effect of temperature on engine gas dynamics." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241518.
Full text
18
Porter, Heidi S. "The effect of febrile temperature on Plasmodium falciparum /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2225.pdf.
Full text
19
Porter, Heidi Sue. "The Effect of Febrile Temperature on Plasmodium falciparum." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1573.
Full textAbstract:
Previously it has been shown that cultures of Plasmodium falciparum died following exposure to a febrile temperature of 40°C, as demonstrated by a decrease in parasitemia of the following generation. In the current study, the effect of 40°C treatment on culture media, erythrocytes, and parasite glucose consumption, were ruled out as possible influences on parasite death, demonstrating that 40°C impacted the parasites directly. Metabolic profiling of DNA synthesis, protein synthesis, and glucose utilization during exposure to 40°C clearly indicated that febrile temperatures had direct effect on major metabolic pathways and parasite development, beginning 20-24 hr after erythrocyte invasion. The ring stages were relatively refractory to heat and recovered completely if returned to 37°C. The mechanism of parasite death was investigated for evidence of an apoptosis-like pathway in cells treated with 40°C, chloroquine, and staurosporine. Lack of typical physiological hallmarks, namely, caspase activation, characteristic mitochondrial membrane potential changes, and DNA degradation as indicated by DNA laddering, eliminated ‘classical’, apoptosis as a mechanism of parasite death. Parasites dying under the influence of 40°C, staurosporine, and chloroquine initially appeared pyknotic in light and electron microscopy, as in apoptosis, but eventual swelling and lysis of the food vacuole membrane led to secondary necrosis. Initially, chloroquine did induce DNA laddering, but it was later attributed to occult white blood cell contamination. While not apoptosis, the results do not rule out other forms of temperature-induced programmed cell death.
20
Parks, Olivia Waverly. "Effect of water temperature on cohesive soil erosion." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/49663.
Full textAbstract:
In light of increased stream temperatures due to urbanization and climate change, the<br />effect of water temperature on cohesive soil erosion should be explored. The objectives of this study are to: determine the effect of water temperature on the erosion rates of clay; determine how erosion rates vary with clay mineralogy; and, explore the relationship between zeta potential and erosion rate. Samples of kaolinite- and montmorillonite-sand mixtures, and vermiculite-dominated soil were placed in the wall of a recirculating flume channel using a vertical sample orientation. Erosion rate was measured under a range of shear stresses (0.1-20 Pa) for a period of five minutes per shear stress at water temperatures of 12, 20, and 27�"C. The zeta potential was determined for each clay type at the three testing temperatures and compared to mean erosion rates. The kaolinite erosion rate doubled when the temperature increased from 12 to 20�"C, and erosion of vermiculite samples tripled when the temperature increased from 20 to 27�"C. The montmorillonite samples generally eroded through mechanical failure rather than fluvial erosion, and the limited fluvial erosion of the montmorillonite-sand mixture was not correlated with water temperature. The data suggest correlation between zeta potential and erosion rate; however, due to the small sample size (n=3), statistically significant correlation was not indicated. Research should continue to explore the influence of water temperature on cohesive soil erosion to better understand the influence of clay mineralogy. Due to the high degree of variability in cohesive soil erosion, multiple replications should be used in future work. The vertical sample orientation enabled discrimination between fluvial erosion and mass wasting and is recommended for future studies.<br>Master of Science
21
Doluweera, D. G. Sumith Pradeepa. "Effect of Weak Inhomogeneities in High Temperature Superconductivity." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1227215152.
Full text
22
Pack, Jessica Spencer. "Effect of Localized Temperature Change on Vigilance Performance." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1429286666.
Full text
23
Van, den Berckt Tom. "The ecological effect of Acacia saligna in a sand plain fynbos ecosystem of the Western Cape, South Africa." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53104.
Full textAbstract:
Thesis (MScFor)--Stellenbosch University, 2002.<br>ENGLISH ABSTRACT: The invasive Australian acacia, A. sa ligna, is widespread in the Western Cape, South Africa, and
is widely used by local communities. Not surprisingly, the introduction of the biological control
agent, the fungus Uromycladium tepperianum in 1987 was received with mixed emotions. In an
effort to determine the socio-economical and ecological impact of the fungus, the Department of
Water Affairs and Forestry has commissioned a study, of which this thesis forms part.
For this thesis, a number of parameters, environmental as well as biological, were sampled,
analyzed and compared with existing data from previous studies. The goal was to obtain a
comprehensive estimation of the effect of A. saligna on a Sand Plain Fynbos community near
Atlantis and to assess whether or not, the detrimental effect A. saligna has on plant biodiversity,
has reached the stage where it has become irreversible. The floristic data confirmed results from
earlier studies, that invasion of A. saligna in Fynbos communities induces a decline in plant
diversity, especially in dense acacia thickets. This study mainly revealed structural changes rather
than community shifts. The enrichment of the soil as noted by others authors was also confirmed
for the study area. However, it was outside the scope of this study to determine the long-term
effects of this enrichment on the Sand Plain Fynbos communities. Soil moisture content was
sampled on three different occasions, in densely invaded and uninvaded study plots. The aim was
to see if A. saligna had any influence on the availability of water in the upper soil. Contrary to
expectations, moisture content under acacia stands was higher in spring and early summer in the
top soil than in pristine fynbos. Pitfall traps were used to sample the arthropods that dwell the
surface of the study area. For arthropods in general, the survey did not produce conclusive data,
but spider species seem to be positively affected by the presence of A. saligna, probably due to
the structural diversity they add to the fynbos. This study revealed that the full ecological impact
of A. saligna on its environment is far from understood, mainly due to the richness and
complexity of the fynbos communities and a lack of research about faunal aspect of the Fynbos
ecosystem.<br>AFRIKAANSE OPSOMMING: Die Australiese akasia, A. saligna, is wydverspreid in die Wes-Kaap, Suid-Afrika, en word
dikwels gebruik deur die plaaslike gemeenskap. Dit is dan nie verbasend dat die invoering van die
biologiese bestrydingsmiddel, die swam Uromycladium Tepperianum in 1987, met teenstrydige
emosies ontvang is nie. In 'n poging om die sosio-ekonomiese en ekologiese impak van die swam
te bepaal, het die Department van Waterwese en Bosboukunde 'n ondersoek aangevra waarvan
die tesis deel vorm. Vir die tesis word 'n aantal parameters, omgewings sowel as biologies,
geproef, geanaliseer en vergelyk met bestaande data van vroeër navorsing. Die doel van die studie
is om te bepaal watter effek A. saligna op 'n sandpleinfynbos gemeenskap naby Atlantis het en
om sodoende vas te stelof die nadelige effek van A. saligna op die biodiversiteit onomkeerbaar
is. Plantaardige data bevestig resultate uit vroeër studies dat A. saligna 'n afuame in plant
diversiteit, veral in digte akasiabosse, veroorsaak. In die studie word getoon dat die toename van
A. saligna strukturele veranderings in plaas van gemeenskaplike verskuiwings tot gevolg het. Die
verryking van die grond, deur ander navorsers genoteer, word ook in die studie bevestig. Dit is
egter buite die veld van studie om die lang termyn gevolge van die verryking van die grond op die
sandpleinfynbosgemeenskap te beslis. Op drie verskillende geleenthede word die watergehalte
van die grond getoets onder die akasiabosse en die fynbos. Die doel van die toetse is om vas te
stel hoe A. saligna die beskikbaarheid van water in die boonste grondlaag beïnvloed. In
teenstelling is hoër vogtigheidsvlakke in die boonste grondlaag onder die akasiabosse as onder
die fynbos gevind gedurende lente en vroeë somer. Lokvalle is gebruik om monsters te neem van
die antropodieë woonagtig op die oppervlak van die studiearea. Oor die algemeen is die opname
vir die antropodieë onvoldoende. Dit is egter insiggewend dat die spinnekopspesies voordeel trek
uit die aanwesigheid van A. saligna. Dit is waarskynlik omdat die akasia strukturele diversiteit
aan die fynbos verleen. Die studie onthul dat die volle ekologiese impak van A. saligna op sy
omgewing moeilik verstaanbaar is as gevolg van die diversiteit en kompleksiteit van fynbos
asook 'n gebrek aan navorsing.
24
Hagemann, Andreas. "Cold storage of eggs of Acartia tonsa Dana: effects of light, salinity and short-term temperature elevation on 48-h egg hatching success." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13002.
Full textAbstract:
Copepods play a key role in the marine ecosystem where they form a vital trophodynamic link between primary and tertiary producers, and are the dominant prey of many marine fishes during their larval stage. Because of their naturally high nutritional quality, copepods are excellent alternatives to traditional live feed organisms for intensive marine fish production. For aquaculturists, it is important to have continuous access to live feed organisms when rearing altricial fish larvae. Cold stored subitaneous copepod eggs are highly relevant as inoculum for culturing live food.In the present study, the effects of light, salinity and short-term elevations in temperature on the 48-h hatching success (HS, %) of cold stored (2 °C) A. tonsa eggs were evaluated. A light experiment exposed the eggs to three different environments with respect to light for a period of up to 7.5 months; one treatment exposed the eggs to an artificial light source, the second treatment had eggs stored in complete darkness, and the third treatment had eggs stored under the storage conditions applied at NTNU Sealab (SSC-treatment). A salinity experiment stored eggs in seawater of four different salinities (34, 50, 75 and 100 ) for a period of up to 7.5 months to evaluate if this was beneficial for long-term cold storage of A. tonsa eggs. A short-term temperature elevation experiment was conducted in order to simulate shipping conditions with insufficient cooling for consignments of A. tonsa eggs. Cold stored eggs were exposed to temperatures elevated to 9 and 17 °C for 12 and 24 hours, with and without oxygen present in the storage media, whereupon they were put back in cold storage for a period of one week before determining the HS.The results for the light experiment showed that light had a profound negative effect on the HS of the cold stored A. tonsa eggs. No hatching was observed for eggs that were stored under constant light after 3 months of cold storage. Eggs stored in darkness showed a significantly higher HS at the final sampling of month 7.5 compared to the SSC treatment, and less dispersion in HS between the replicates throughout the experiment. The salinity experiment showed that the eggs could be stored in seawater with a salinity of 50 for up to 3 months with a high HS, whereas storage in seawater of 75 and 100 showed a low HS for most samplings and thus proved as a poor cold storage media. The short-term elevation in temperature experiment showed that the HS was significantly affected by the oxygen concentration in the seawater upon a cold storage period of 3 weeks, and that short-term elevations in temperature, up to 17 °C for a duration of 24 hours, did not significantly affect the HS when hatched one week after the onset of incubation. The viability of the hatched nauplii post temperature exposures was assessed in a feeding incidence experiment. It showed that neither of the conducted temperature elevations utterly inhibited the nauplii from feeding.
25
Kirca, Onder. "Temperature Effect On Calcium Aluminate Cement Based Composite Binders." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607454/index.pdf.
Full textAbstract:
In calcium aluminate cement (CAC) systems the hydration process is different than portland cement (PC) systems. The hydration products of CAC are subjected to conversion depending on temperature, moisture, water-cement ratio, cement content, etc. Consequently, strength of CAC system can be seriously reduced. However, presence of other inorganic binders or additives may alter the hydration process and improve various properties of CAC based composites.
The objective of this study is to investigate the temperature effect on the behaviour of CAC based composite binders. Throughout this research, several combinations of CAC-PC, CAC-gypsum, CAC-lime, CAC-ground granulated blast furnace slag (CAC-GGBFS) were studied. These CAC based composite binders were subjected to seven different curing regimes and their strength developments were investigated up to 210 days. In addition, the mechanism of strength development was examined by XRD analyses performed at 28 and 210 days. Finally, some empirical relationships between strength-time-curing temperatures were formulated.
Experimental results revealed that the increase in ambient temperature resulted in an increase in the rate of conversion, thereby causing drastic strength reduction, particularly in pure CAC mix. It has been observed that inclusion of small amount of PC, lime, and gypsum in CAC did not induce conversion-free CAC binary systems, rather they resulted in faster conversion by enabling rapid formation of stable C3AH6 instead of metastable, high strength inducing CAH10 and C2AH8. On the other hand, in CAC-GGBFS mixes, the formation of stable straetlingite (C2ASH8) instead of calcium aluminate hydrates hindered the conversion reactions. Therefore, CAC-GGBFS mixes, where GGBFS ratio was over 40%, did not exhibit strength loss due to conversion reactions that occurred in pure CAC systems.
26
Calmunger, Mattias. "Effect of temperature on mechanical response of austenitic materials." Thesis, Linköpings universitet, Konstruktionsmaterial, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73748.
Full textAbstract:
Global increase in energy consumption and global warming require more energy production but less CO2emission. Increase in efficiency of energy production is an effective way for this purpose. This can be reached by increasing boiler temperature and pressure in a biomass power plant. By increasing material temperature 50°C, the efficiency in biomass power plants can be increased significantly and the CO2emission can be greatly reduced. However, the materials used for future biomass power plants with higher temperature require improved properties. Austenitic stainless steels are used in most biomass power plants. In austenitic stainless steels a phenomenon called dynamic strain aging (DSA), can occur in the operating temperature range for biomass power plants. DSA is an effect of interaction between moving dislocations and solute atoms and occurs during deformation at certain temperatures. An investigation of DSA influences on ductility in austenitic stainless steels and nickel base alloys have been done. Tensile tests at room temperature up to 700°C and scanning electron microscope investigations have been used. Tensile tests revealed that ductility increases with increased temperature for some materials when for others the ductility decreases. This is, probably due to formation of twins. Increased stacking fault energy (SFE) gives increased amount of twins and high nickel content gives a higher SFE. Deformation mechanisms observed in the microstructure are glide bands (or deformations band), twins, dislocation cells and shear bands. Damage due to DSA can probably be related to intersection between glide bands or twins, see figure 6 a). Broken particles and voids are damage mechanisms observed in the microstructure.
27
Salinas, Rodríguez Armando. "Effect of temperature on texture development in zirconium alloys." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75850.
Full textAbstract:
A theoretical and experimental study is presented of texture evolution in hcp zirconium deformed at high temperatures. It is shown that, within the temperature range in which nuclear components are fabricated, the development of crystallographic texture is controlled by the simultaneous activation of $ langle$a$ rangle$ and $ langle$c + a$ rangle$ slip. This is demonstrated by experiments on Zr-2.5 Nb and unalloyed Zr deformed along three of the four elementary strain paths: axisymmetric elongation and compression and pure shear. Further experimental work on the axisymmetric deformation of unalloyed Zr and Zr-20 Nb shows that the influence of the bcc $ beta$-Zr phase present in Zr-2.5 Nb at the temperatures of interest is not due to the formation of crystallographic textures in this phase.<br>Texture evolution modelling was implemented for the case of polycrystalline hcp metals by making use of the duality principle between the generalized Taylor and Bishop-Hill theories of polycrystal plasticity and with the help of linear programming. The high temperature experimental textures for the three elementary strain paths mentioned above were successfully predicted using the relaxed constraint theory. It is shown that, for the cases of pure shear and compression, the so-called pancake version of this approach gives a better approximation to the observed textures than the full constraint calculations. For axisymmetric elongation, the curling version of the relaxed constraint model gives the best results.<br>By the analysis of slip activity maps, it is shown that the limitations of the full constraint model reside in the high activity level for $ langle$c + a$ rangle$ slip associated with this approach. When the relaxed constraint model is applied, the activity level of $ langle$c + a$ rangle$ slip is considerably reduced, leading to much better agreement of the predicted textures with the experimental results. The full constraint model is also applied to simulate texture evolution in $ alpha$-Zr deformed in simple shear at room temperature. It is demonstrated that the level of agreement is at least as good as that obtained when full constraint calculations were carried out. Finally, a high temperature texture rosette is proposed for prediction of the textures developed during tube forming operations for Zr alloy nuclear components. (Abstract shortened with permission of author.)
28
Naperalsky, Michael E. "Effect of post-exercise environmental temperature on glycogen resynthesis." The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-06052009-115319/.
Full textAbstract:
Hotter environments can often alter the normal exercises responses of metabolism and work performance compared to exercise in a more neutral condition. The goal of this study was to determine the effects of a hot (H) and room temperature (RT) environment on glycogen resynthesis during recovery from exercise. Recreationally active males (n = 9) completed two trials, each with 60-min of cycling exercise at 60% of maximum watts in a temperature-controlled chamber (32.6°C), followed by 4 hours of recovery at the same temperature (H) or 22.2°C (RT). Subjects were fed a carbohydrate beverage (1.8 g/kg bodyweight) at 0 and 2 hours post-exercise. Muscle biopsies were taken from the vastus lateralis at 0, 2, and 4 hours post-exercise for analysis of muscle glycogen. Blood samples were collected at 0, 30, 60, 120, 150, 180, and 240 minutes of recovery for glucose and insulin analysis. Ambient and core temperatures were monitored for the duration of the trial. Expired gas was collected prior to 2- and 4-hour biopsies for calculation of whole-body carbohydrate (CHO) oxidation. Glycogen, core temperature, CHO oxidation, and blood marker values were analyzed using two-way ANOVA with repeated measures. Average core temperature was significantly higher in H compared to RT (38.1°C ± 0.01° vs. 37.9°C ± 0.08°, p<0.05) during recovery. Glycogen was not different at 0 and 2 hours post-exercise. However, at 4 hours post-exercise muscle glycogen was significantly higher in RT vs. H (105 ± 28 vs. 88 ± 24 mmolkg-1 wet weight, respectively). Blood glucose levels were similar between H and RT for the first two hours, but showed lower values (p<0.05) in RT compared to H at time points 150, 180, and 240 minutes post-exercise. CHO oxidation during recovery was higher in H compared to RT (0.36 ± 0.04 g/min vs. 0.22 ± 0.03 g/min, respectively, p<0.05), with greater CHO oxidation at 4-hours post-exercise in both trials. Glycogen resynthesis during recovery is impaired in a hot environment, likely due to increased oxidation of CHO instead of synthesis.
29
Zeiher, Carolyn A., Paul W. Brown, Jeffrey C. Silvertooth, Nkonko Matumba, and Nancy Mitton. "The Effect of Night Temperature on Cotton Reproductive Development." College of Agriculture, University of Arizona (Tucson, AZ), 1994. http://hdl.handle.net/10150/209598.
Full textAbstract:
A field study was initiated in the summer of 1993 to investigate the effect of increased night temperatures on cotton reproductive development. DPL 5415 was planted on May 10. Treatments consisted of two temperature regimes placed in a completely randomized design with four replications. The two temperature treatments were initiated at first bloom and treatments terminated after 6 weeks. Cotton grown under ambient night temperature served as the control treatments while plants where the infrared radiation balance was modified to increase the nighttime foliage temperature served as the high night temperature treatment. This study showed that increasing the nighttime foliage temperature of cotton reduced vegetative dry matter production, plant height, and fruit retention. The photosynthetic capacity of the two treatments was not significantly different, suggesting that increased respiration at these higher nighttime foliage temperatures may be responsible for the reduction in assimilated carbon which contributed to the poor fruit retention.
30
Caunce, Maria. "The effect of age upon temperature regulation in humans." Thesis, Queen Mary, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410037.
Full text
31
Su, Yu Chu Joan. "The effect of interfacial phenomena on high temperature processes." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423096.
Full text
32
Graham, Phillip William. "The effect of temperature on Plodia - natural enemy interactions." Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414743.
Full text
33
Williams, W. "The effect of time and temperature on magnetic remanence." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382523.
Full text
34
Huang, Yan. "Temperature dependent hall effect studies of GaN on sapphire /." Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42577068.
Full text
35
Perconte, David. "Proximity effect between a high temperature superconductor and graphene." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS119.pdf.
Full textAbstract:
Nous avons fabriqué des jonctions YBCO graphène, nous avons étudié dans un premier temps le transport électronique à l'interface entre ces deux matériaux ainsi que le mécanisme - la réflexion d'Andreev - par lequel un courant porté par des électrons est transformé en courant par des paires de Cooper. Nous avons observé des interférences électroniques en fonction du niveau de dopage du graphène. Ces interférences correspondent au tunneling de Klein d'électrons normaux quand l'énergie de ces électrons dépassent le gap supraconducteur. A plus basse énergie, ce sont les paires de Cooper qui passent la barrière par effet tunnel de Klein. Dans un deuxième temps, nous avons fabriqué des jonctions YBCO graphène dont la taille est comparable à la longueur de cohérence du graphène. Nous avons observé d'une part un comportement tunnel de la conductance dans le cas où l'interface graphène YBCO est sale. Dans le cas où l'interface YBCO graphène est propre, nous avons observé des oscillations de la conductance de la jonction en fonction de la tension de biais ainsi que de la tension de grille. Ces oscillations semblent provenir d'interférences électroniques dans le canal de graphène entre les électrodes supraconductrices. Enfin, nous présentons une nouvelle méthode de fabrication de jonction phi à base de BSCCO<br>We have fabricated YBCO graphene junction. We studied the electronical transport at the interface between these two materials as well as the mechanism - the Andreev reflexion- by which a current carried by electrons is transformed into a current carried by Cooper pairs. We observed electronic interferences as a function of graphene doping. This modulation comes from the presence of a potential barrier at the interface between YBCO and graphene in which the particles are circulating before being transmitted or reflected. These interferences correspond to Klein tunneling of normal electrons when their energy is higher than the superconducting gap. At lower energy, Cooper pairs can traverse the barrier by Klein tunneling. We later fabricated YBCO graphene junctions which size is comparable to the graphene coherence length. We observed tunnel conductance when the interface between graphene and YBCO is opaque. In the case when the interface is transparent, we observed oscillations of the junction conductance as a function of the bias voltage and of the gate voltage. These oscillations seem to originate from electronic interferences inside the graphene channel between the superconducting electrodes. We also propose an experimental method to fabricate phi junction based on BSCCO
36
Hagberg, William. "Temperature effect on insert tool life in dry machining." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-83933.
Full textAbstract:
This thesis work researched the temperature effects the insert tool life. This was examined through physical laboratory testing with designed milling tools and temperature simulations in ANSYS. The designed milling tools altered the temperature in the insert through external parameters like design and material. Three milling tools were used in total: A milling tool created in an copper alloy that cools the inserts, a milling tool created in the material idun that increases the temperature in the inserts, and the milling tool Coro Mill 245 that was used as a reference. These tools were tested with two inserts, insert 1130 with a coating of PVD, and insert 4330 which has a coating of CVD. The idun milling tool and the reference milling tool was already designed, but the copper milling tool was designed during the thesis work. The designed copper milling tool implemented a heat sink to cool the milling tool with convection and was manufactured in a copper alloy with high strength. The copper milling tool was 20 $\%$ colder than the reference milling tool when comparing the maximum temperature of the insert. Through testing in dry milling of the three milling tools with different inserts and a simulation in ANSYS of the temperature development, the conclusion was that insert 4330 had crater wear which increased with increased temperature. This crater wear can be the main factor in the insert tool life.
37
Elvin, Malin. "The effect of humidity and temperature on paper properties." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-54905.
Full textAbstract:
The study was performed at Billerudkorsnäs at the section Box Lab which offers knowledge and solutions for packaging. Paper that can be used to create packaging interacts with the surrounding environment, but has only been tested for a few climates. This thesis aims to investigate more climates and see how paper is affected by humidity and temperature and try to determine the cause of the results. The methods used to measure this was primary tensile test and moisture content analysis but also a test to evaluate creep was performed in climates with high humidity. From this, the mechanical properties of the paper were calculated. The test was performed in a climate chamber and the choice of methods was limited by what could be performed in the climate chamber. The materials tested were chosen to give a good representation of what is commonly used in the containerboard business. The climates for testing were selected from the ability of the climate chamber as well as interesting climates for the company. The results show that the papers are weakest at high RH, but the results indicate that the temperature solely impacts the properties of the paper. The highest moisture content does not necessarily mean the lowest value for a chosen property. The causes for the results are not clear since the patterns found are not bound to a certain quality but rather to paper in general. Therefore, more research on the area is suggested to try to determine what causes the material to react to temperature.
38
Lin, Muh-Ren. "Experimental Investigation of Temperature Effect on Uniaxial Tensile Test." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1392371542.
Full text
39
Lin, Muh-ren. "Experimental investigation of temperature effect on uniaxial tensile test /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487266011224679.
Full text
40
Duncan, Julia Carmel. "The effect of nitrogen, niobium and temperature of the high temperature oxidation of titanium aluminide alloys." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49663.
Full textAbstract:
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.<br>Includes bibliographical references (leaves 237-247).<br>This is especially attractive for reducing the engine weight and increasing the thrust/weight ratio. Increasing the operating temperature and thereby the engine efficiency has approached the maximum possible operating temperature for currently used materials. A model set of three intermetallics -- unalloyed [gamma]-TiAl, unalloyed [alpha]-Ti 3Al and a nearly stoichiometric Ti2NbAl (an orthorhombic intermetallic structure) -- was chosen and investigated under a variety of experimental conditions. Gas mixtures of varying oxygen concentrations in both argon and nitrogen allowed the effect of oxygen concentration on oxidation kinetics to be investigated. The Ti 2NbAl-alloy was specifically chosen to examine the effect of Nb in a intermetallic compound (with Nb substituting for one Ti in the Ti 3Al intermetallic structure). This is in contrast to Nb as a simple alloy addition to y-TiAl or c 2-Ti 3Al. Exposures at temperatures of 700°C and 800°C for 20 and 100 hours were studied (compared to temperatures of 900°C or higher used by other investigators), since these temperatures promoted a more protective scale. Additionally, the scale composition is sensitive to temperature and restricts the conventional practice of corrosion study acceleration by raising the experimental temperature. The resulting corrosion scales were analyzed using electron microscopy (scanning and transmission), x-ray diffraction and thermogravimetric analysis. The effect of nitrogen in the gaseous environment was explored. The impact of Nb on the oxidation of the intermetallics was found to be more protective than what might be expected from examining the thermodynamics and kinetics of the Ti-Al-Nb-O-N system. At times an alternating layered scale structure resulted and the effect of N, Nb and the lower temperatures used in this study is summarized. The oxidation rate of the Ti 2NbAl-alloy fell between the rates for y-TiAl and c 2-Ti 3Al, with the scale on y-TiAl growing at the slowest rate of the three compositions. However, the superior mechanical properties of Ti2 NbAl-alloy combined with the acceptable corrosion resistance promote its consideration for replacing those portions of the engine operating at intermediate temperatures that would result in significant weight and cost savings.<br>by Julia Carmel Duncan.<br>Sc.D.
41
Ferian, Michael R. "The Effect of Global Temperature Increase on Lake-Effect Snowfall Downwind of Lake Erie." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1229968622.
Full text
42
Cyrus, Mark. "Does the foliage of Acacia spp. determine their distribution? : a study to determine how two different leaf forms may alter the distribution of Acacia spp. in relation to phosphorus concentration, mean annual precipitation and temperature within Australia and South Africa." Bachelor's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/26656.
Full textAbstract:
The genus Acacia consists of over 1000 species, of which most are native to Australia. An intriguing aspect of this genus is their divergence into two major groups that poses entirely different leaf structures. The first of these groups consist of Acacias have fern like bi-pinnate leaves, that are subdivided into small leaflets. The other group posses' what are known as phyllodes which are also called 'simple leaves'. The evolution of phyllodes within the genus Acacia seems to have been localized, occurring largely within Australia. Many hypotheses have been put forward in the past to try and explain what advantages phyllodes incur on the species that bear them. Many studies have indicated drought tolerance and resistance as a main evolutionary driver of phyllodes. However due to the very low concentrations of nutrients particularly P within Australia and the generally longer life span exhibited by phyllodes compared to normal compound leaves, we hypothesized that phyllodes were in fact an adaptation to nutrient limitation, and provide a way in which to limit nutrient loss back to the environment. In order to test our hypothesis, we analysed the distributions of 6 Acacia spp., three of which were phyllodinous and three of which bore compound leaves, in relation to soil P concentrations, mean annual precipitation and temperature. Due to all 6 of these species being invasive within South Africa we compared their distribution of these species both within Australia and South Africa to determine wither species were following similar trends. In this study we determined that phyllodinous Acacia spp. were occurring on low P soils at significantly higher frequencies to species bearing compound leaves. The reverse relationship however was also recorded for areas of high P with compound leaf bearing species being more dominant. Species followed similar trends between continents, however due to these species being invasive in SA it was assumed that species had not reach their ideal or potential distribution ranges which may mean that trends may become stronger with time. Temperature and rainfall did not show any relationship to foliage type and it was there for concluded that phosphorus concentrations have been the main evolutionary driver of the phyllode.
43
Tong, Man Vincent, and 董文. "Temperature distribution in highway bridges." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31223497.
Full text
44
Beyers, Gregory John. "An experimental study of the effect of Acacia mearnsii (black wattle trees) on streamflow in the Sand River, Eastern Cape." Thesis, Rhodes University, 1999. http://hdl.handle.net/10962/d1005507.
Full textAbstract:
This thesis explores the effect of Acacia mearnsii on streamflow in the Eastern Cape. There is a need for data on the localised effects of removing alien trees from the riparian zones within the Fynbos Biome. Fynbos catchments throughout the Western and Eastern Cape yield large quantities of good quality water which is an essential resource in the region. To convince local land owners to manage their riparian zones, small scale experimental results will prove invaluable to assure them of the immediate advantages for themselves and for downstream water users. Three permanent weirs were built 500 m apart to monitor the effect of removing A. mearnsii on streamflow in the Sand River, Eastern Cape. Consecutive weirs allowed for the comparison of streamflow between a cleared and uncleared section of the river without significant differences in riparian conditions, channel morphology and vegetation densities. A site survey confirmed comparable densities of A. mearnsii in both sections. A sample of trees was weighed and a relationship was found between diameter at breast height and above ground wet biomass. Between the first two weirs, 2.5 ha of riparian zone was cleared amounting to approximately 160tlha. Streamflow was monitored from the 10th of January 1996 to the 9th of September 1996. The average streamflow reduction for the duration of the experiment was 15.1 m³/ha/day or 551 mm per annum. Initially, after a period of above average rainfall, streamflow was augmented by discharge from the riparian zone but as conditions dried out, there was a net uptake of water with the highest average uptake of 23. 7m³/ha/day in June. A comparison between weather conditions and streamflow reduction indicated there is a complex relationship, with evidence of A. mearnsii exhibiting control of water loss during dry conditions. Acacia mearnsii trees in the riparian zone have been shown to cause significant streamflow reduction. Permanent weirs were found to be appropriate for this type of study. There is a need for further research on the effect of alien trees in riparian zones around South Africa as there is potential for significant increases in streamflow.
45
Lee, Siu-lam Anderson, and 李韶林. "Temperature distribution in steel structures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3122300X.
Full text
46
Wollmuth, Lonnie Paul. "Norepinephrine and temperature regulation in goldfish." PDXScholar, 1987. https://pdxscholar.library.pdx.edu/open_access_etds/3727.
Full textAbstract:
Cannulae were implanted into forebrain loci of goldfish (Carassius auratus; 45-90 g) to determine (i) the effects and site of action of intracranial norepinephrine (NE) injections on behavioral thermoregulation and (ii) the mechanism and the types of adrenoreceptors involved in the thermoregulatory effect of NE. After 30 min in a thermal gradient, implanted fish were injected with norepinephrinebitartrate salt (2.5-500 ng NE) in a total volume of 0.2 ul (carrier was 0.7% NaCl). Injections of 5, 10, 25, and 50 ng NE into the anterior aspect of the nucleus preopticus periventricularis (NPP1 Peter and Gill 1975) led to consistent, dose-dependent decreases in selected temperature. No effect on temperature selection was observed following injections of 2.5 ng NE or control injections of 100 ng tartaric acid. The effects of injections into other loci, including intraventricular injections, were dependent upon the dose and proximity to the anterior NPP1 at sites adjacent to the anterior NPP, larger doses were required, and the effects became inconsistent. At sites further removed, no effect on selected temperature was observed1 included in this category were more caudal sites within the NPP and the nucleus preopticus.
47
Parletta, Mary Ann. "Growth control of Australian acacias." 1996. http://web4.library.adelaide.edu.au/theses/09A/09ap252.pdf.
Full textAbstract:
Copies of author's previously published material inserted. Bibliography: leaves 212-227. This thesis describes the research aimed to produce a small flowering pot plant of Acacia less than 35 cm high with more than 50 inflorescenses within twenty four months, a potted foliage plant less than 35 cm high within twelve months or a flowering tub plant less than 1m high with more than 50 inflorescences within thirty six months. This study produces a protocol for production of flowering pot plants of A. acinacea using a comination of pruning and paclobutrazol.
48
CHOU, WAN-YU, and 周琬喻. "Effects of High-temperature Treatment on the Plate Vibration Properties and Physical Properties of Sitka Spruce and Taiwan Acacia." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3gwue5.
Full textAbstract:
碩士<br>國立宜蘭大學<br>森林暨自然資源學系碩士班<br>104<br>Wooden string instruments are popular in music since ancient times. Related to the problems of large variations of relative humidity in Taiwan which can induce acoustical quality of string instruments, this study aims to improve the acoustical quality of wooden boards using high-temperature treatment. A plate vibration method was used to investigate the effects of 130°C and150°C treatment on vibrational properties of sitka spruce and Taiwan acacia through the resonant frequencies of (1,1), (2,0), and (0,2) mode.The results showed that the shrinkages of high-temperature treated wood according to the dimension changes between 90%, 70%, and 50% were lower than those of control samples. The color change of wood surface after 150°C treatment was more obviously. An increase in modulus of elasticity along longitudinal and radial direction, shear modulus in LR section of test specimens were observed after high-temperature treatment. The internal friction of longitudinal and radial flexural and torsional vibrations of test specimens was reduced after high-temperature treatment. The percentage increases in specific dynamic modulus of elasticity, sound radiation ratio, and acoustic conversion efficiency were greater after 130°C high-temperature treatment for Sitka spruce and 150°C high-temperature treatment for Taiwan acacia. The improvement of those acoustical assessment factors could lead to a better sound quality of string instruments. Overall, the high-temperature treatment could improve the acoustical quality and mechanical performance, and significantly reduce the water absorption of wood.
49
CHEN, OU-PO, and 陳歐珀. "The effect of press drying on the properties of kraft sheet of Taiwan acacia (Acacia confusa Merr.)." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/77973453661831186886.
Full text
50
Lotz, Michelle Karen. "The effect of elevated CO2 levels on the growth of two Acacia species." Thesis, 2001. http://hdl.handle.net/10413/5315.
Full textAbstract:
Climate change, induced by increases in the concentration of greenhouse gases in
the atmosphere, can affect the growth and community structure of ecosystems in
two ways. Firstly directly through changes in atmospheric concentration of CO2, and
secondly indirectly through changes in temperature and rainfall. The aim of the
present investigation was to test the effect of elevated CO2 and altitude-related
temperature differences on the growth of two species of Acacia that form important
components of the vegetation of KwaZulu-Natal.
Plants of Acacia sieberana and Acacia nilotica were grown in chambers at elevated
(700 pll-1) and ambient (350 IJW1) CO2 with and without rhizobial inoculation. Both
treatments (elevated CO2 and the presence of rhizobial inoculation) stimulated
growth and branching. A. nilotica was the most responsive to both elevated CO2
level and inoculation. Inoculated plants showed greater increases in mass and
height than uninoculated plants. While elevated CO2 had a significant effect on
plant mass, height and leaf area accumulation, other factors, such as species type
and rhizobial inoculation had a somewhat greater influence on the short term mass
accumulation under elevated CO2 , Significant differences existed between the
average percentage leaf nitrogen for the two species (P < 0.001), and for inoculated
and uninoculated plants (P < 0.005).
There were no significant differences in photosynthetic rates (A) at any internal CO2
concentration (Cj) between plants grown in elevated CO2 compared to those grown
under ambient conditions. When photosynthesis was plotted against C, (A/CJ, the
initial slopes of the graphs for both A. sieberana and A. nilotica were shallower for
plants grown in elevated CO2 , compared to plants grown in ambient conditions ,
indicating a decreased Rubisco concentration at low C, and greater nitrogen use
efficiency. At higher C; A. sieberana continued to have lower A in plants grown at
elevated CO2 levels suggesting an inability to regenerate RuBP or the possible
accumulation of soluble carbohydrates. A. nilotica grown in elevated CO2 had a
slightly increased Pj regeneration capacity at higher CO2 concentrations. While the
A/Cj results demonstrate that CO2 ·has a minor effect on photosynthesis, growth
responses indicated otherwise. This is a result often reported and indicates the
importance of measuring as many parameters as is possible to determine actual
plant responses to elevated CO2 levels.
In the field experiment, the effect of temperature was studied by transplanting
twenty plants of each species at three different elevations in the Drakensberg at
Cathedral Peak. Plant height, mass, condition and finally survivorship were
measured . All of these attributes decreased as elevation increased. Plants growing
at the highest elevation all died back prior to winter while those growing at lower
elevations grew throughout the experimental period. Results suggest that elevation
and hence temperature are important factors controlling Acacia distribution. If the
greenhouse gas induced increases in temperature occur as predicted, and the
estimated latitudinal migration rates of 30-100km per decade are required for
species to remain within their current climatic envelopes, it is expected that the
structure and appearance of vegetation in the Drakensberg will change markedly
with global warming . The presence or absence of Rhizobia in the soil will further complicate this. Those plants that have access to the elevated nitrogen levels as
a result of these root nodule bacteria will have a distinct advantage over
competitors growing without them.<br>Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.