Tropical Climate Countries Research Articles

Renewable Energy Analysis and Evaluation with Economic Utilization of Solar Powered Air Conditioning System in Nigeria

This article focuses on the analysis and integration of PV systems to load ratio correlation and the economic importance of the left over to grid supply and integration. The paper focusses on the different methods of PV generation to load utilization using the solar powered air conditioner as the load while minimizing the use of fossil fuel (petroleum, natural gas and coal) which have serious environmental implications. Air conditioners are becoming more commonly used load power consumption metrics and are a major strain on energy demands especially in tropical rainforest climate countries like Nigeria. The photovoltaic electricity is a clean and sustainable energy. In this paper, we present a techno-economic feasibility study for solar powered air conditioning system in Nigeria. The method used made a correlation of four alternatives of PV to load ratio factor being investigated. In the first instance, the PV system supplied 50% of the energy to the loads. In the second method, the PV system supplied 75% of the energy to the loads. Thirdly, the PV system supplied 100% of the energy to the loads. Fourthly, on a final design, the PV system supplied 125% of the energy to the loads. In the first two case the PV energy generated is used solely to power the air conditioner system. In the last two design, there is excess electrical energy which is proposed to be sold to the Nigeria grid system especially if the grid system optimized and broken down into smaller grid array within 0.3$ feed-in tariff. The best alternative method is the grid-connected PV system with 125% capacity factor which is chosen due to its short payback time period as well as high profit rate over the lifetime of the project.

Optimal sizing and placement of battery energy storage system for maximum variable renewable energy penetration considering demand response flexibility: A case in Lombok power system, Indonesia

Indonesia is a tropical climate country with considerable renewable electrical energy source prospects, including photovoltaic (PV) and wind energies. Nevertheless, several variable renewable energy sources (VREs) have exhibited uncertain attributes and substantial reliance on natural conditions, leading to unstable load-related power supply risks. Hence, integrating battery energy storage systems (BESSs) with VRE generators is a dependable approach to bolster renewable energy generator applications on a large-scale grid while providing load demand flexibility. This study determined adequate sizing and placement of the BESS to achieve maximum VRE generator penetration while considering the demand response flexibility. Key indicators, including technical minimum load and system ramp capacity, were identified to achieve maximum penetration of thermal generators. This study also combined a unit commitment procedure with direct current optimal power flow (DC-OPF) as a novel approach to determine the maximum VRE penetration level. An optimization problem model concerning mixed integer linear programming (MILP) was subsequently employed in this study using the CPLEX solver in the general algebraic modeling system (GAMS). The study is based on the IEEE RTS-24 system modified and a real-life case study of the Lombok energy system in Indonesia. Results from the simulated Lombok power system highlighted that optimal sizing and placement of the BESS could lower system costs by 37.66%, 33.63%, and 22.26% compared to the current system conditions during the weekday, weekend, and the lowest day scenarios, respectively. The VRE penetrations of the generators were also higher than the current system conditions by 83%, 51%, and 39% during the weekday, weekend, and the lowest day scenarios, respectively.

The design of solar power thermoelectric radiant panel as cooling system in small buildings under tropical climate

The usage of an air–conditioning (AC) system in any building is necessary to maintain its indoor thermal comfort and health. However, this system consumes a lot of energy, while the usage of refrigerant causes irreversible damage to the ozone layer. To solve this problem, a solar thermoelectric radiant panel (PV-TERP) system has a high potential in replacing conventional AC system because it requires no refrigerant and easier to be controlled due to the absence of moving and mechanical parts such as water pumps, compressors, including auxiliary and hydronic pipes. Meanwhile, the usage of solar energy in the PV-TERP system can also help reduce fossil energy consumption and carbon emissions. The main objective of this work is to design a new PV-TERP system for replacing conventional AC systems in buildings located in tropical climate countries, like Malaysia. It is found that the designed PV-TERP system can provide up to 4.84 kW of cooling power, which is about 0.6% higher than the cooling load of targeted rooms. Here, the targeted rooms operate under indoor parameters within the acceptable range of ASHRAE standard-55. The obtained results clearly show that the new design is applicable to be used as a cooling system for the targeted building. In the future, it is then essential to understand the thermal properties and mechanism of the design via simulation process, followed by experimental validation to support the design feasibility. In conclusion, this new design of PV-TERP will lead the path toward expanding renewable energy applications for cooling purposes in sustaining and preserving the environment. HIGHLIGHTS Alternative cooling system in replacing air-conditioning (AC) system for maintaining indoor thermal comfort without harming the environment. Designation of the PV-TERP system as a cooling system for building in a tropical country (Malaysia) under indoor parameters within the acceptable range of ASHRAE Standard-55. The designed PV-TERP is refrigerant-free and operates using renewable energy, which can sustain and preserve the environment for a better future. GRAPHICAL ABSTRACT

Mosquito as West Nile Virus Vector: Global Timeline of Detection, Characteristic, and Biology

Mosquitoes are extremely important vectors that transmit zoonotic West Nile virus (WNV) globally, resulting in significant outbreaks in birds, humans, and mammals. The abundance of mosquito vectors combined with the migratory flying behaviour of wild birds across the globe has exacerbated the dynamics of WNV infection. Depth understanding of the WNV infection requires a comprehensive understanding of the character of the vector in terms of their taxonomy, morphology, biology, behaviours, preferences, and factors that promote their breeding. Most susceptible animals and humans may experience serious neurological illnesses such as encephalitis. Little is known about the susceptibility of mosquitoes to WNV infection. This review provides insightful knowledge about the characteristics of mosquitoes that carry WNV and their susceptibility to WNV infection. The context of mosquito’s involvement in WNV transmission is demonstrated through space and time from the 1950’s until to date. The historical timeline of WNV transmission strength was significantly intensified via the complex interactions between vector, virus, and environment. Such knowledge will provide valuable insights into vector control intervention mitigation strategies, especially in tropical climate countries like Malaysia.

Enhanced Technique for Prediction of Z-R Relationship in Tropical Region

Over the years, research has been directed to investigate radar as potential tools for estimating rain. The radar reflectivity is measured by comparing the location of the rain gauge and the associated vertical path at certain altitude. The latitude and longitude of the rain gauge is identified to pinpoint the exact associated location by using Rainbow®5 meteorological software. In this work, radar reflectivity was estimated by using S-band Terminal Doppler Weather Radar (TWDR) data at Malaysian KLIA radar station. The rain gauge is owned by Malaysian Department of Irrigation and Drainage (DID) at several locations within the vicinity of the radar. A technique to estimate the Z-R relationship by using radar reflectivity information and rainfall rate from rain gauge values is demonstrated in this article. Comparisons between radar reflectivity and actual rain gauge measurement is presented. Preliminary findings using available Z-R relation shows similar values with the actual measurement and suitable to be used in tropical climate country such as Malaysia.

Inhibitory Test Of Citronella Essential Oil (Cymbopogon Nardus L. Rendle) Againts Aspergillus Flavus Growth

Background: Indonesia is the one of tropical climate country with high air humidity. It becomes the main factor of fungal infection, that is called otomycosis, which is caused by Aspergillus flavus. The treatment of otomycosis is usually done by giving an azole antifungal drugs that can give the beneficial and adverse effects. Treatment of otomycosis can be done with various kinds of herbs. One of herbs that is used, it is citronella. Citronella contains essential oil 0,4% and in citronella essential oil contains citronellal 32-45% and geraniol 12-15% has ability as an antifungal. The aim of this study is to determine the inhibitory of citronella essential oil against Aspergillus flavus growth. Methods: The type of this research is laboratory experiments with posttest only with control group design. 24-hour Aspergillus flavus is used as the research subjects which had been inoculated on SDA media and given essential oils in various concentrations of 0.5%, 1.0%, 1.5%, 2.0 %. The observation of citronella essential oil inhibitory as an antifungal by measuring the diameter of inhibitory zone, it uses a caliper. Results: The measuring from average diameter of Aspergillus flavus fungal growth zone in each concentration, they are 0.5% ;1.0%; 1.5%; 2.0% is 9.11 mm; 12.03 mm; 13.62 mm; 16.81 mm. The higher concentration of essential oil, it makes the wider diameter of the inhibition zone. The level of sensitivity is intermediate, sensitive, sensitive, sensitive. The level of effectiveness is less effective, effective enough, effective, very effective. The results of statistical analysis showed that citronella essential oil has the inhibitory against Aspergillus flavus growth. Conclusion: this study was various concentration of citronella essential oil have a significanteffect on the growth of inhibitory Aspergillus flavus.

Fault detection using acceptance ratio analysis on polycrystalline grid-connected photovoltaics system

<p><span lang="EN-US">Around the world, electricity generation from PV photovoltaic systems is increasing, achieving 10-20% PV system efficiency. However, PV systems degrade due to the technology and the operating conditions and become worse in tropical climate countries. Hence, degradation is one of the key performance indicators for the reliability assessment of a PV system. This paper presents the acceptance ratio (AR) analysis grid-connected photovoltaic (GCPV) located on the campus of the Universiti Teknologi MARA, Shah Alam, Malaysia as the key performance indicators. A comparative analysis of the actual and predicted AC Power and AR of the polycrystalline GCPV system is carried out over monitoring of a one-year period. MATLAB software is chosen to simulate the output power using actual data. Malaysian Standard MS2692:2020 has noted that the AR value must ≥ 0.9 to classify as accepted in testing and commissioning tests and AR < 0.9 has been indicated as a non-accepted GCPV system. The results of acceptance ratio (AR), yield (Y), specific yield (SY), and performance ratio (PR) show that almost half of the AR’s data results show below 0.9 with the performance ratio of PV systems was less than 75%, indicating that the systems needed to be completely replaced.</span></p>

Improvement of a soundproofing vent hole

In tropical climate countries, the house structure with a vent hole is widely used. The vent hole has a structure that penetrates the house's outer wall, allowing fresh air from outside to enter the room. However, external traffic noise also enters the living spaces through the vents. A novel type of soundproof vent hole unit with both soundproofing and ventilation functions was proposed in previous work. An elliptical cavity was used for this unit, but it is difficult to manufacture an elliptical cavity with a high eccentricity; also, the installation and adjustment work are expected to be difficult. A rectangular cavity with an inlet and outlet in orthogonal planes fitted to the house walls is used in this study to provide soundproofing functionality to the vent hole. First, the generation mechanism of sound pressure components propagating inside the unit was theoretically elucidated using the three-dimensional wave equation. Second, to maximize soundproofing ability, methods for reducing the number of resonances and reducing the effect of higher-order sound pressure components are described.

BLACK SOYBEAN RESPONSE TO ANTIOXIDANT APPLICATION FOR GROWTH AND YIELD UNDER SALINITY STRESS CONDITIONS

Black soybean (Glycine max L.) is native to Asia and well adapted to tropical climate countries, such as, Indonesia. The demand for black soybean supply increases due to soy sauce making. Limited fertile land causes efforts to enhance black soybean production to relocate to sub-optimal lands, such as, saline land. However, in saline soils the plant productivity is very low; therefore, technological inputs are required to prevent the crop from salinity stress, one of which is an exogenous application of antioxidants. The presented study aimed to analyze the yield in several black soybean cultivars when applied with antioxidants under salinity stress conditions. The study used a randomized complete block design with a factorial arrangement and three replications. The first factor comprised four cultivars of black soybean, i.e., Malika, Detam 2, Detam 3, and Detam 4, while the second factor was antioxidants (ascorbic acid, salicylic acid, and vitamin E – α-tocopherol) application, and without application of antioxidant (control). The results showed that salinity stress significantly affected the growth and yield of four black soybean cultivars. However, cultivar Detam 2 compared with other cultivars, performed best based on morphological and yield-related traits under saline soil conditions. Furthermore, in antioxidants, salicylic acid gave the best results for morphological characters, while ascorbic acid and vitamin E performed better for yield-related traits. Overall, the antioxidant application increased the tolerance of black soybean genotypes as compared with the control under salinity stress conditions.

Revisiting In vitro Micropropagation Protocols of Mimosa pudica for Enhanced Seed Germination, Shoot Multiplication, and Root Initiation

Mimosa pudica is a medicinal plant worthy of therapeutic properties. It is often overlooked as one of the weed species, and the potential was underappreciated despite its abundance in nature, particularly in tropical climate countries. Considering the aptitude of this species, the micropropagation protocol of M. pudica was revisited and enhanced. The seed surface sterilization and germination were assessed, followed by shoot multiplication rate and root initiation efficiency. Seeds of M. pudica were best surface sterilized with 35% of Clorox and recorded the highest germination rate at 65.55% in media of three-quarter strength Murashige and Skoog (MS) combined with 30 g of sucrose. The explants were harvested and subcultured into multiplication media fortified with 6-benzylaminopurine, kinetin, and coconut water. The highest number of new shoots and leaves were obtained at 3 shoots and 3.27 cm in media of MS combined with 17.6 μm kinetin. Half-strength MS media devoid of hormone was recommended for root induction, resulting in the 5 healthy roots at 2.06 cm after 4 weeks of culture. Overall, the developed micropropagation protocol of M. pudica could facilitate its large-scale cultivation, indicating its potential as a medicinal crop for the extraction of bioactive compounds.

Comparison of Machine Learning Algorithms for Classification of Ultraviolet Index

Indonesia is a tropical climate country which has the potential for high intensity of sunlight exposure. Several types of exposure that receives are ultraviolet rays. According to the National Agency for Meteorology, Climatology and Geophysics, it provides information regarding the impact on human activities in an ultraviolet index which has a risk scale. The aim of this research was creating a recommender system based on the ultraviolet index category in providing daily activity advice to users. The methods used the K-nearest Neighbor algorithm and Support Vector Machine with a Collaborative Filtering Model-Based approach that could recommend items based on the results of a model trained to identify input data patterns. The stages carried out in this study included data collection, data pre-processing, data division into test data and train data, dataset testing, analysis of the results of models that had been trained in the accuracy values using the algorithm tested. The results of the confusion matrix calculation produced test evaluations in accuracy values, precision values, and recall values. The comparison of result had the highest performance in K-nearest Neighbor with an accuracy value of 99.69%, a precision value of 99.00%, and a recall value of 96.20%. In research used the Support Vector Machine showed the lowest performance with an accuracy value of 97.91%, a precision value of 93.20%, and a recall value of 86.40%.

Magnesium Oxide Nanoparticles: Effective Antilarvicidal and Antibacterial Agents.

People are vulnerable to mosquito-borne infections in tropical and subtropical climate countries. Due to resistive issues, vector control is an immediate concern in today's environment. The current study describes the synthesis of magnesium oxide by four different approaches including green, microwave, sol-gel, and hydrothermal methods. The synthesized magnesium oxide (MgO) nanoparticles were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), and energy-dispersive X-ray analysis (EDAX) techniques. The FT-IR studies reveal the presence of functional groups in the synthesized nanoparticles. The structural and morphological studies were investigated using XRD and HRSEM. EDAX reveals the presence of Mg and O in the prepared samples. The synthesized MgO NPs were screened for antibacterial studies against Gram-positive strains, Enterococcus faecalis and Staphylococcus aureus, two Gram-negative cultures, Escherichia coli and Klebsiella pneumoniae, using different concentrations. The results indicated excellent antibacterial activity against both Gram-positive and Gram-negative bacteria at 50 mg/mL hydrothermally produced MgO nanoparticles, with a maximal zone of inhibition (ZOI) of 5 mm for S. aureus, 7 mm for E. faecalis, and 6 mm for K. pneumoniae. The ZOI of E. coli was found to be the greatest at 9 mm when 50 mg/mL sol-gel-produced MgO nanoparticles were used. The synthesized MgO nanostructures were tested against fourth-instar larvae of Aedes aegypti and Aedes albopictus, and the hydrothermally synthesized MgO nanostructures exhibited better results when compared with other methods of synthesis. The reports show that A. aegypti and A. albopictus mortality rates were reported to be the lowest with green-manufactured MgO nanoparticles (7.5 g mL-1) and the highest with hydrothermally synthesized MgO nanoparticles (120 g mL-1). The research indicates that MgO nanostructures are promising drugs for antibacterial and mosquitocidal larvae control properties.

The techno-economics of growing high-value temperate crops under controlled soil temperature on tropical climate lowland

Demand for high-value temperate fruits and vegetables such as lettuce, cabbage, and berries have increased with population growth despite decrease in available space for cultivation due to urbanisation. These crops particularly grow well under low soil temperature, hence their cultivation pose huge challenge in the hot tropics except on a few cool highlands and via greenhouse farming. Outputs from these methods are always complemented with importation to meet the demand. Studies have however shown that low soil temperature gives the right conditions for microbes that promote development of these crops. This study presents application of solar thermal chilled water for agricultural soil cooling, and the economic analysis of the cooling process. The analytical and experimental models show the cooling process is technically feasible. However, to ascertain its financial viability, additional scenarios with 1 kW, 5 kW and 10 kW cooling capacities were analysed together with the experimental size of the developed system of cooling. This shows that the viability of the system improves from 5 kW cooling capacity. In addition to all other widely cultivated crops, implementation of the proposed system would promote local production of temperate crops hence diminish heavy reliance on importation of these crops in tropical climate countries and enhance food security.

Daily temperature effects on under-five mortality in a tropical climate country and the role of local characteristics

BackgroundClimate change and its subsequent effects on temperature have raised global public health concerns. Although numerous epidemiological studies have shown the adverse health effects of temperature, the association remains unclear for children aged below five years old and those in tropical climate regions. MethodsWe conducted a two-stage time-stratified case-crossover study to examine the association between temperature and under-five mortality, spanning the period from 2014 to 2018 across all six regions in Malaysia. In the first stage, we estimated region-specific temperature-mortality associations using a conditional Poisson regression and distributed lag nonlinear models. We used a multivariate meta-regression model to pool the region-specific estimates and examine the potential role of local characteristics in the association, which includes geographical information, demographics, socioeconomic status, long-term temperature metrics, and healthcare access by region. ResultsTemperature in Malaysia ranged from 22 °C to 31 °C, with a mean of 27.6 °C. No clear seasonality was observed in under-five mortality. We found no strong evidence of the association between temperature and under-five mortality, with an “M-” shaped exposure-response curve. The minimum mortality temperature (MMT) was identified at 27.1 °C. Among several local characteristics, only education level and hospital bed rates reduced the residual heterogeneity in the association. However, effect modification by these variables were not significant. ConclusionThis study suggests a null association between temperature and under-five mortality in Malaysia, which has a tropical climate. The “M-” shaped pattern suggests that under-fives may be vulnerable to temperature changes, even with a small temperature change in reference to the MMT. However, the weak risks with a large uncertainty at extreme temperatures remained inconclusive. Potential roles of education level and hospital bed rate were statistically inconclusive.

The potential of one-part alkali-activated materials (AAMs) as a concrete patch mortar

One-part alkali-activated materials (AAMs) are developed to improve conventional two-part systems. One-part AAMs technology has been used in cement binders to produce concrete, mortar, and paste. Current research mainly focuses on synthesizing raw materials obtained from industrial and agricultural waste as the main aluminosilicate precursors of the cement binder for a concrete application. The one-part AAMs were reported to have higher early compressive strength at 7 days of age, contributed by its fast-setting time, mainly when the binder activates by a higher dosage of alkaline activator and containing OPC-rich. Due to bonding issues, single or combination, FA/GGBFS/MK precursors were reported as unsuitable for use as a concrete repair material. They were the reason for the lack of one-part AAMs application of mortar compared to concrete usage. This study was conducted to determine the potential of one-part AAMs used as concrete patch mortar by investigating its rheology and mechanical properties. The compressive strength of the mortar was tested under lab ambient temperature in the tropical climate country of Malaysia. The setting time of fresh mortar and bonding strength were set under controlled lab temperature. The one-part alkali-activated mortar was composed of hybrid aluminosilicate precursors between fly ash (FA), Ground Granulated Blast Furnace Slag (GGBFS) and ordinary Portland cement (OPC). A low alkaline activator of solid potassium carbonate was used for the geopolymerization process. Three types of solid admixtures were added to complete the composition of the new mix design. The experiment's outcome showed that the mortar composed with the combination of conventional Portland cement and industrial waste products has compressive and pull-off adherence strength that meets with Class R3—EN1504-3 standard for structural concrete repair materials requirement.

The Influence of a Tropical Climate with a Long Dry Season on Goat Semen Quality and Seminal Fluid Change in the Kanchanaburi Province, Thailand

At present, there is no information about the difference between the three seasons with a long dry period, such as Kanchanaburi province, Thailand, on goat semen quality. This study observed the climate and daytime length effects of a long dry period in three seasons in a tropical climate country on goat semen quality and seminal fluid change. The semen was collected from eight male goats once a month for one year. The libido score was assessed during semen collection. Semen volume, semen sediment volume, percentage of seminal fluid volume, seminal fluid protein, mass movement, motility, concentration, and spermatozoa membrane integrity were evaluated. Libido scores were not different between the seasons. Semen volume, seminal fluid volume, and seminal fluid protein concentration in the rainy season were significantly higher (p<0.05) than in the summer and winter. Semen sediment volume was relatively stable in all seasons and months. Meanwhile, the concentration was significantly higher (p<0.05) in the summer and winter than in the rainy season. In summer and winter, spermatozoa motility and normal spermatozoa membrane were significantly higher (p<0.05) than in the rainy season. In conclusion, temperature, THI, and daytime changes in tropical climate countries with long dry seasons were unrelated to semen quality, seminal fluid change, and sexual behavior. But the increase in humidity in the rainy season after long dry seasons has dropped semen quality, resulting from increased volume and protein levels in seminal fluid.

Formulation And Anti-Aging Effectiveness of Sheet Mask Formula Containing Macadamia Oil

Aging is an inevitable physiological process that must be experienced by every human being. This process is irreversible which includes all organs of the body including the skin. The skin is one of the tissues that will directly show the aging processes. Premature aging can happen to anyone. Especially in Indonesia, which is a tropical climate country with higher intensity sunlight. The degenerative process in skin that is too often exposed to ultraviolet light takes place more quickly to aging. Premature aging can happen to anyone. Especially in Indonesia, which is a tropical climate with higher intensity sunlight. The degenerative process in skin that is too often exposed to ultraviolet light takes place more quickl.

Local Community Knowledge for Flood Resilience: A Case Study from East Coast Malaysia

Malaysia as a tropical climate country is vulnerable to dreadful climate change events; particularly floods. These frequent occurrences of floods severely affect one or other parts of the country. In reducing disaster risk and strengthening local initiatives towards climate adaptation, vulnerable communities particularly in rural areas have developed valuable local knowledge for flood resilience. This local knowledge is continuously practiced in facing disasters and it is passed down to the next generations. This study aims to examine measures taken by communities based on local knowledge they possessed from the three stages of disaster management cycle namely, before, during and after disaster. Local knowledge as asserted by scholars could complement scientific knowledge and build a comprehensive disaster risk reduction approach for local context implementation. A mixed method approach was adopted; case study method and household survey involving 90 respondents for quantitative data collection and field observation for collecting qualitative data. Three case study areas in East Coast of Malaysia have been selected for further observation including; 1) Lubok Setol village in Kelantan state; 2) Teladas village in Terengganu state; and 3) Gajah Mati village in Pahang state. Findings from this study indicated that all study cases have developed and adopted local knowledge strategies for flood preparedness and responses including; 1) agriculture techniques and livestock trading; 2) stock piling of food and other necessities; 3) marking flood level as historical record; 4) floodproofing animal shelter; 5) constructing overhead storage cabinet and outdoor hut, and; 6) saving boats for emergencies. As a conclusion, it is proven that local community knowledge plays crucial roles in reducing disaster risks hence contributing towards building a resilient community.

3-Dimensional Numerical Modelling to Assess Geothermal Piles Efficiency in Tropical Countries

Nowadays, climate changes caused by intense and continuous greenhouse gases emission is one of the most curtail issues that facing the human beings. Throughout the years, researchers have tried to find other reliable sources available to control the exhaustion of coal, gases, and oil. Geothermal energy is one of these alternatives that have been investigated and considered as one of the most promising renewable and clean energy sources. Tropical climate countries such as Malaysia could benefit from this technology due to its high cooling demand throughout the year. Geothermal piles for instance, are one of the methods that can be used to extract geothermal energy by employing the piles as a heat transfer bodes. Therefore, this paper presents numerical simulations as an early attempt to realise the potential of adopting geothermal piles catered to Malaysia’s soil condition and pile standards for low-rise construction. A pipe with a U-tube shape wase simulated at three different inner diameters (14, 19, and 26) under two inlet dischargers (0.009 m3/s 0.050 m3/s). The U-tube was placed inside concrete square pile with dimensions of 1.5 m width, 1.5 m length and 10 m hight. The simulation was conducted under two soil conditions namely, (i) dry soil, and (ii) soil effected by groundwater. The performance of the geothermal pile was measured by the amount of temperature reduction in the pipe outlet after heat exchange has been done. The results obtained showed that geothermal piles with lower flow discharge (0.009 m3/s) operation produced more temperature reduction in the pipe outlet. Without the presence of groundwater, the 26 cm diameter recorded the highest temperature reduction, with pipe outlet temperature of 29.89 °C equivalent to a 1.0 % reduction. Similarly, with the groundwater effect, the same pipe diameter recorded the highest temperature reduction, with pipe outlet temperature of 28.43 °C equivalent to a 1.57 % reduction. Based on the numerical modelling results it can be said that combination of 26 cm pipe diameter, at 0.009 m3/s flow rate, and the advection effect of groundwater temperature has produced an optimum condition for the geothermal piles in cooling system.

A Review of Traditional Uses, Phytochemistry and Pharmacological Properties of Some Vietnamese Wound-Healing Medicinal Plants

Wound healing is a sophisticated process that results in the repair of damaged tissues. Any impairment to this process can lead to non-healing (chronic) wounds. Since these can cause a massive burden on the healthcare system, alternative therapies that promote wound healing should be considered. Therapies of natural origins that are safe and with no adverse side effects are especially promising. Vietnam, a tropical-climate country, has many medicinal plants that possess the potential for healing wounds. This report explores the use of some common plants used in Traditional Vietnamese medicine and their molecular mechanisms.