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http://cmuir.cmu.ac.th/jspui/handle/6653943832/7576
2024-03-29T12:12:32ZA novel oceanic index derived from sea surface height in the South China Sea
http://cmuir.cmu.ac.th/jspui/handle/6653943832/79378
Title: A novel oceanic index derived from sea surface height in the South China Sea
Authors: Krittaporn Buathong
Abstract: In this thesis, we propose a novel oceanic index based on sea surface height anomaly (SSHA) to forecast rainfall in each region of Thailand. We first investigate lead-lag relationships between some of the well-known oceanic and atmospheric indices, commonly used for studying, and rainfall in each region. We next investigate spatial and temporal variations of SSHA variability in the South China Sea over the period of January 1993 to December 2022 using Empirical Orthogonal Function (EOF) analysis. Results of the EOF analysis show high and low oscillation patterns in the studied region along with their associated Principal Component (PC) time series. The 2nd PC time series shows significantly strong correlation with the rainfall in each region. However, the direct use of PC time series are computationally costly. Instead, we use SSHA information within the dominant regions, which show high variances observed in the 2nd mode of EOF analysis. Results of EOF lead a way to create a new oceanic index called the South China Sea Index (SCSI). We then explore the correlation between this new index and the rainfall in each region of Thailand. Results show that the SCSI has strong correlation with rainfall in each region. To forecast rainfall in each region in Thailand, we formulate models using the Seasonal Autoregressive Integrated Moving Averages with Exogenous Variables (SARIMAX) model by combining the oceanic and atmospheric indices used in studying climate change with a novel time series-index based on SSHA developed in this study. The results of this research will help predict monthly regional Thailand's rainfall, leading to a better understanding of rainfall variations in each region of Thailand.2023-11-01T00:00:00ZPhotocatalytic properties of V2O5/TiO2 Nanoheterostructure films prepared by sparking method
http://cmuir.cmu.ac.th/jspui/handle/6653943832/79364
Title: Photocatalytic properties of V2O5/TiO2 Nanoheterostructure films prepared by sparking method
Authors: Porntipa Pooseekheaw
Abstract: Photocatalysis is widely studied to solve water scarcity in some countries which an
increasingly serious problem. This process is clean and provides great products for
environment. The designs of porous morphologies and composite with metal oxide into
titanium dioxide (TiO2) films have been an effective way to improve photocatalytic
efficiency. Therefore, in this research we studied the photocatalytic performance of
porous vanadium pentoxide/titanium dioxide (V2O2/TiO2) nanoheterostructure films
prepared by the one-step sparking method.
The first part focuses on the concentration of vanadium in films, which annealed at 400
°C, to improve the uniformity of films prepared by the sparking method at room
temperature and atmospheric pressure. The atomic ratios of titanium/vanadium (TiV) on
films were observed at 4:1, 2:1, 1:1, and 1:2 for TiV-1, TiV-2, TiV-3, and TiV-4 samples,
respectively. The as-deposited films had the porosity morphology of small particles for
all prepared films, which the average secondary particle sizes increase with enhancing
the proportion of vanadium. The existence of V4+ in V2O5/TiO2 nanoheterostructure films
had an importance effect on photocatalytic efficiency. The energy band gap of all
prepared films was reduced by increasing of vanadium portion and obtained at 3.28. 3.12.
2.84, 2.63. 2.56, and 2.32 eV for TiO2, TiV-1, TiV-2, TiV-3, TiV-4, and V2O5 films,
respectively. Furthermore, TiV-3 sample, which Ti/V atomic ratio approximately 1:1,
presents the highest degradation rate of methylene blue solution (MB) and large interface
heterojunctions. The degradation rate of MB increased by 24% and 30% when compared
with pure TiO2 and V2O5 films, respectively. Thus, this work provides the method, which
can produce V2O5/TiO2 nanoheterostructure films in one step and can potentially apply
to photocatalytic applications.
In the second part, the V2O5 TiO2 nanoheterostructure films were fabricated on quartz
substrates by a sparking method using a strong external magnetic field (0.5 T) with a
different arrangement of magnetic flux. The effect of magnetic flux direction on
V2O5/TiO2 films was investigated by placing the substrates on south, north, parallel, and
45 degrees of the magnetic poles, which were labeled as TVS, TVN, TVP, and TVH
respectively. The samples, which pre- and post-annealed at 400 *C for one hour at
atmospheric pressure without applying magnetic field during sparking were labeled as
TV and TVA, respectively. The SEM images display that placing the substrates in
different directions of the magnetic field clearly affects the morphology of composite
films. TVP and TVH samples, which are positioned more strongly influenced by the
magnetic force, show arrangement of particles along magnetic field lines, while TVN and
TVS are evenly distributed. The TiO2 (anatase/ rutile) phase and V2O5-VO2 modification
phase were fabricated that confirmed by Raman spectroscopy, and XPS results without
the annealing process. we assumed that the phase transformation from amorphous to
crystalline film is the result of the applied magnetic field during the parking process. The
energy band gap (Eg) of TV, TVH, TVP, TVN, TVS, and TVA were obtained to 2.90,
2.45, 2.68, 2.70, 2.78, and 2.60 eV, respectively, which was modified by the strong
magnetics field. The TVH sample show the highest photocatalytic performance up to
41%, which was a 30 % and 270% compared to the without magnetic fields TVA and TV
samples, respectively after 1- hour visible light irradiation. This works offers an
interesting approach to developing film synthesis without annealing process.2022-03-09T00:00:00ZAssessing the potential of climate-smart agriculture to improve food security and climate-change resilience of Highland in Northern Thailand
http://cmuir.cmu.ac.th/jspui/handle/6653943832/79360
Title: Assessing the potential of climate-smart agriculture to improve food security and climate-change resilience of Highland in Northern Thailand
Authors: Thatchakorn Khamkhunmuang
Abstract: Climate change is expected to affect highland smallholder farmers with poor and
limited resources. For the case study of Ban Tub and Pang Hin Fon sub-districts. Mae
Chaem district, Chiang Mai province, the objectives were to assess food security,
climate change vulnerability, and emission of CO2 of highland agricultural systems and
to design and assess a Climate-Smart Agriculture system supporting food security,
climate resilience, and CO2 emission reduction. Participatory Rural Appraisal (PRA) of
communities and ethnic groups was done. There were key informant interviews with 2-
3 persons per village and focus group discussion in the topics; theory and timeline of
village, food security assessment, risk and vulnerability, indicator development, design
and assessment of CSA about shifting cultivation with 120 persons and semi-structure
interviews of 196 smallholders farming houses. The results showed that 49.50% of the
food was plants, and 59.25% of the income was from selling plants. Ban Muad Long
had the most food and income from crop production. As for Mae Kee Muk Noi, the
villagers had the most access to food sources from the market because the distance was
the closest than the other villages. Ban Mae Hae Tai had better food stability from the
forest than the other villages. From the risk and vulnerability analysis, it was found that
agriculture posed the highest risk up to 30 %, within which 25 % was from low
productivity. For the risk on the low productivity, the villagers thought that they could
rarely cope, as low as 5%, which could lead to loss of produce and incomes, which in
turn lead to food insecurity. In the land preparation plots, the greenhouse gases emission
in upland rice cultivation were 4.23 scores (out of 5, agree) in the Karen and 3.18 scores
(out of 5, undecided) in the Lawa. Moreover, all of the villages used chemicals that are
unnecessary leading to increase of greenhouse gases in the future. For the results of
indicators development, it was found that there were 9 topics, 27 indicative components,
and 76 indicators, and 14 actions plans were designed. Then, an assessment into a
shifting cultivation system in the future was done. Under climate change and the current
community context, appropriate ecological services and biodiversity were suggested
from some action plans that might have long-term effects on food production and food
security.2021-04-02T00:00:00ZThe Influences of Kai Genera Cladophora and Rhizoclonium on Caddisfly Larval order Trichoptera communities in Nan River, Nan Province
http://cmuir.cmu.ac.th/jspui/handle/6653943832/79336
Title: The Influences of Kai Genera Cladophora and Rhizoclonium on Caddisfly Larval order Trichoptera communities in Nan River, Nan Province
Authors: Pornpimon Buntha
Abstract: In the upper part of Nan River, macro-filamentous green algae (genera
Cladophora and Rhizoclonium, collectively "Kai" in the vernacular) are usually found
in the cobble habitat in the cool season. Caddisfly larvae (Trichoptera) also live in the
cobble habitat. Therefore, objectives in this study are as follows; 1) to find out
influences of Kai algae on caddisfly larval communities and 2) to study a role of the
algae on caddisflies in families Hydropsychidae and Hydroptilidae in term of food
resources. Eight study sites in the Thung Chang to Chiang Klang Districts were
determined for this study. Samples were collected once a month during January 2017 to
December 2018. In the first part of methods, two areas were determined per a study site
included Control (CT) and Kai algal blooming (KB) areas during Kai algal blooming
period. Less than 20% of Kai algae covering on cobbles within a Surber sample were a
Control area. More than 80% of Kai algae covering on cobbles within the Surber sample
were a Kai algal blooming area. Kai algal and caddisfly larval samples were collected
within 25x25 cm2 of the Surber sample equipment, 10 replicates per one area. In the
second part of methods, Hydropsychidae and Hydroptilidae larvae were brought to
study about eating behaviors with fresh Kai algae and food items in their foreguts. In
the third part of methods, physicochemical factors of air and water temperature, water
velocity, pH, electrical conductivity (EC), total dissolved solids (TDS), dissolved
oxygen (DO), biochemical oxygen demand (BOD5), water hardness, ammonia nitrogen
(NH3-N), nitrate nitrogen (NO3-N) and orthophosphate (PO43-) in the Nan River were
measured once a month. Thirteen and fifteen families of caddisfly larvae were found in
the CT and KB areas, respectively. Number of families of caddisfly larvae in the KB
areas were significantly higher than the larvae from CT areas at p< 0.05. Densities of
caddisfly larvae in 13 families from the KB areas were significantly higher than the CT
areas. These results indicated Kai algae had positive effects to 13 families of caddisfly
larvae. Kai algal eating behaviors were found in Hydropsychidae and Hydroptilidae
larvae. Hydropsychidae larvae ate fresh filaments of Kai. Hydroptilidae larvae ate cell
fluids of fresh Kai algae. Food items in 18 Hydropsychidae larval foreguts from CT
areas were 4 types by area included 44.66% of Kai algae (KA), 32.18% of other items
such as plant and insect remain (OI), 22.17% of diatoms (DT) and 0.46% of other
filamentous algae (OFA). Food items in 18 Hydropsychidae larval foreguts from KB
areas were also 4 types by area included 78.13% of KA, 14.49% of DT. 3.72% of OI
and 3.65% of OFA. Proportion of KA type in the larval foreguts from the both areas
was higher than other food item types. Proportional comparison about the same food
types in the larval foreguts from the CT areas with KB areas found that proportions of
KA and OFA types in the larval foreguts from the KB areas were significantly higher
than the CT areas. But proportions of DI and OI types in the larval foreguts from the
CT areas were significantly higher than KB areas. The results showed that Kai algae
were important food sources for these larvae. Environmental factors in the Nan River,
included water temperature, pH, EC. TDS, turbidity and water hardness associated with
occurrences of caddisfly larvae. This study found that the environmental factors in the
Nan River during the cool season to the summer were suitable for living of caddisfly
larvae.2022-05-17T00:00:00Z