Search Results (25)

Historical urban environments are frequently abandoned with the rise in expansion. An example is Kendari, a city that is over two centuries old with long historical colonialism, such as the Dutch East Indies and Japan. The city is presently eroded due to modern development and demographic pressure. Therefore, this research aimed to identify how the urban layout of Kendari was used to define long-term preservation procedures. Conzen’s school of urban morphology methodology, utilized for the examination of the historical evolution of the urban landscape and the interaction with present urban development processes, was used to conduct this research. Historical cartographic data and changes in land use were used to perform a detailed examination of the evolution of the street structure, land distribution, and architectural layout. The result showed how historical, cultural, and economic aspects shaped the formation of Kendari old town. In conclusion, this research improved the understanding of Kendari’s historical urban structure, and supplied useful empirical data for planning the future development and conservation of the districts. Full article

Indonesia, located in Southeast Asia, is the world’s largest tropical island country. It is globally recognized as a unique center of biodiversity in the Asian–Australian transitional zone. To date, however, no national plant checklist of Indonesia has been published. Here, we collected botanical information on the flora of Indonesia and presented for the first time a checklist of known native species of vascular plants in the country. Our checklist included 30,466 species belonging to 2968 genera and 317 families, representing 8.7% of the 351,180 vascular plant species worldwide. Among the seven regions, Sumatra had the highest number of species at 10,902, followed by Indonesian New Guinea (9935), Java (9289), Kalimantan (9191), Sulawesi (7048), Maluku (5294), and Lesser Sunda Islands (4514). In contrast, Indonesian New Guinea had a much higher proportion of locally endemic species than other regions (59%). The seven regions were divided into three phytogeographical areas: the Sunda Shelf, the Sahul Shelf, and the Wallacea, based on similarities in floristic composition. Our checklist for Indonesia provides basic information for biodiversity conservation and associated research. Full article

Empirically, in Indonesia, the leaves of Cassia alata L. (candle bush or ketepeng cina) have been used as a topical antifungal agent. Malassezia furfur is a natural microorganism found in the human body. It is among the factors contributing to conditions such as pityriasis versicolor, a common, benign, superficial fungal infection of the skin that is closely associated with seborrheic dermatitis and dandruff. This study aimed to explore C. alata leaves, starting from determining antifungal activity against M. furfur and the identification of major compounds in the ethyl acetate and n-hexane fractions, and then we carried out molecular docking of the major compounds in the n-hexane fraction to lanosterol 14-alpha demethylase. The method was the disc diffusion technique to test antifungal activity, LC-MS/MS for major compound identification, and homology modeling through Swiss Models for molecular docking. The fractions of ethyl acetate and n-hexane extract showed concentration-dependent antifungal activity against M. furfur. The LCMS/MS analysis revealed five major compounds in the ethyl acetate and n-hexane fractions. The molecular docking demonstrated the highest binding affinity with stearidonic acid at −7.2 kcal/mol. It can be concluded that the compounds in the n-hexane fraction have antifungal activity against M. furfur, as supported by both in vitro and in silico studies. Full article

This study measured the concentrations of Hg, As, Ni, Cd, and Pb in six fish species commonly consumed in Kendari. Samples were bought within local markets from 2012 to 2017 at the end of the dry season. Results showed that mercury concentrations fluctuated between years and within species, except in the Caranx sexfasciatus, which showed no significant differences (Kruskall–Wallis, p-value > 0.05, df = 5) and an average concentration of 0.371 ± 0.162 µg g⁻¹ DW. Arsenic was found in high concentrations across species and years and varied widely in C. sexfasciatus, the lowest value being 0.32 ± 0.01 µg g⁻¹ DW in 2012 and the highest was 5.63 ± 1.89 µg g⁻¹ DW in 2017. The highest nickel concentrations were found in 2016 across four of the six species. The fish samples displayed very low cadmium and lead concentrations throughout the study. In addition, the potential human health risk due to fish consumption was assessed. This showed that mercury is the only one of the five metals present in concentrations high enough to individually pose a potential hazard, the only metal likely to be accumulated beyond a safe concentration in Kendari. Chanos chanos never posed a toxicological risk based on the results of this research. Full article

This paper presents four optimization outcomes for a diesel generator (DG), photovoltaic (PV), and battery hybrid generating radial system, to reduce the network losses and achieve optimum generated power with minimum costs. The effectiveness of the four utilized meta-heuristic algorithms in this paper (firefly algorithm, particle swarm optimization, genetic algorithm, and surrogate optimization) was compared, considering factors such as Cost of Energy (COE), the Loss of Power Supply Probability (LPSP), and the coefficient of determination (R²). The multi-objective function approach was adopted to find the optimal DG allocation sizing and location using the four utilized algorithms separately to achieve the optimal solution. The forward-backward sweep method (FBSM) was employed in this research to compute the network’s power flow. Based on the computed outcomes of the algorithms, the inclusion of an additional 300 kW DG in bus 2 was concluded to be an effective strategy for optimizing the system, resulting in maximizing the generated power with minimum network losses and costs. Results reveal that DG allocation using the firefly algorithm outperforms the other three algorithms, reducing the burden on the main DG and batteries by 30.48% and 19.24%, respectively. This research presents an optimization of an existing electricity network case study located on Tomia Island, Southeast Sulawesi, Indonesia. Full article

Indonesia has around 4000 wood species, and 10% (400) of species are categorized as commercial wood. One species is kayu kuku (Pericopsis mooniana Thwaites), native to Southeast Sulawesi. This species is considered a fancy wood used for sawn timber, veneer, plywood, carving, and furniture. The high demand for wood caused excessive logging and threatened its sustainability. In addition, planting P. mooniana has presented several challenges, including seedling production, viability and germination rate, nursery technology, and silviculture techniques. As a result, the genera of Pericopsis, including P. elata (Europe), P. mooniana (Sri Lanka), and P. angolenses (Africa), have been listed in the Convention on International Trade in Endangered Species (CITES) Appendix. Based on The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, P. mooniana is categorized as Vulnerable (A1cd). This conservation status has raised issues regarding its biodiversity, conservation, and sustainability in the near future. This paper aims to review the conservation of potential and endangered species of P. mooniana and highlight some efforts for its species conservation and sustainable use in Indonesia. The method used is a systematic literature review based on P. mooniana’s publication derived from various reputable journal sources and additional literature sources. The results revealed that the future demand for P. mooniana still increases significantly due to its excellent wood characteristics. This high demand should be balanced with both silviculture techniques and conservation efforts. The silviculture of P. mooniana has been improved through seed storage technology, improved viability and germination rates, proper micro and macro propagation, applying hormones, in vitro seed storage, improved nursery technology, and harvesting techniques. P. mooniana conservation can be conducted with both in situ and ex situ conservation efforts. In situ conservation is carried out by protecting its mother trees in natural conditions (i.e., Lamedae Nature Reserve) for producing good quality seeds and seedlings. Ex situ conservation is realized by planting seeds and seedlings to produce more wood through rehabilitating and restoring critical forests and lands due to its ability to adapt to marginal land and mitigate climate change. Other actions required for supporting ex situ conservation are preventing illegal logging, regeneration, conservation education, reforestation, agroforestry system applied in private and community lands, and industrial forest plantations. Full article

Agricultural extension workers play an essential role in the productivity of agricultural systems. Based on the actual conditions in the field, it can be seen that the level of extension services still needs to be higher due to a lack of human resources in the field of extension services. This research was conducted to determine the effectiveness of agricultural extension services andthe factors that influence the effectiveness of agricultural extension to farmers in Baubau City, Indonesia. The analytical method includes exogenous latent variables: human resources, technological progress, farming capital, farmer age, education, and farming experience. The effectiveness of agricultural extension is used as an endogenous latent variable. The research sample consisted of 110 rice farmers in Baubau City, and the Slovin formula was used to calculate the sample. The data collection for this research was carried out by distributing questionnaires to respondents, in-depth interviews, and direct observation in the city of Baubau. Using the AMOS application, quantitative analysis was carried out through structural equation modeling (SEM). The study results show that: (1) The factors that influence the effectiveness of agricultural extension in Baubau City are farming capital, farmer age, education, farming experience, and human resources, and (2) the influence of these factors on the effectiveness of agricultural extension is as follows: if the farming capital is high, human resources can be increased. In addition, the higher the farmer’s age, the lower the need for human resources. It is also noted that higher farmer education contributes to increased human capital, and increased experience in farming is associated with increased human capital. Thus, an increase in human resources will increase the effectiveness of agricultural extension. Significant factors that influence the effectiveness of agricultural extension in Baubau City, Southeast Sulawesi, are farming capital, farmer age, education, farming experience, and human resources. Full article

It is often observed that thermal stress enhances crack propagation in materials, and, conversely, crack propagation can contribute to temperature shifts in materials. In this study, we first consider the thermoelasticity model proposed by M. A. Biot and study its energy dissipation property. The Biot thermoelasticity model takes into account the following effects. Thermal expansion and contraction are caused by temperature changes, and, conversely, temperatures decrease in expanding areas but increase in contracting areas. In addition, we examine its thermomechanical properties through several numerical examples and observe that the stress near a singular point is enhanced by the thermoelastic effect. In the second part, we propose two crack propagation models under thermal stress by coupling a phase field model for crack propagation and the Biot thermoelasticity model and show their variational structures. In our numerical experiments, we investigate how thermal coupling affects the crack speed and shape. In particular, we observe that the lowest temperature appears near the crack tip, and the crack propagation is accelerated by the enhanced thermal stress. Full article

Bacterial cellulose (BC) based on sago liquid waste has been developed to be used as food packaging. This study investigated the physicochemical and mechanical properties of modified BC film and its application as food packaging. The modified BC film performed carboxymethyl cellulose (CMC) as a stabilizer and glycerol as a plasticizer. Films were prepared by casting technique using BC as the primary material and composites with various concentrations of CMC and glycerol (0.5%, 1%, and 1.5%, v/v). BC film was applied as the packaging of meat sausage, and the quality of meat sausage was measured based on weight loss, moisture content, pH, protein content, and total microbial count. The addition of CMC and glycerol influences the physical and mechanical properties of BC composites film. The best mechanical properties of edible BC film were collected by adding 1% CMC and 1% glycerol with a tensile strength of 17.47 MPa, elongation at a break of 25.60%, and Young’s modulus of 6.54 GPa. FTIR analysis showed the characteristic bands of BC, and the addition of CMC and glycerol slightly changed the FTIR spectrum of the composites. The utilization of modified BC-based sago liquid waste film as the packaging of meat sausage could maintain sausage quality during 6 days of storage at room temperature. Therefore, edible BC film has the potential to be used as food packaging. Full article

The Towakkalak System located in the Maros karst of South Sulawesi is currently the richest of Southeast Asia in obligate subterranean species. It comprises several caves and shafts that give access to the subterranean Towakkalak river as well as many unconnected fossil caves, stream sinks, and springs located within its footprint. The total length of the caves linked to the active system is 24,319 m and comprises two of the longest caves of Indonesia, Gua Salukkan Kallang and Gua Tanette. Studies of its fauna began in 1985. There are 10 stygobionts and 26 troglobionts that are known from the system. The smaller adjacent system of Saripa has 6 stygobionts and 18 troglobionts, of which 1 and 3, respectively, are absent from Towakkalak. Like all tropical cave inventories, our dataset has limits due to identification uncertainties, gaps in habitat (waters, guano) and taxonomic coverage (micro-crustaceans, mites), sampling methods (pitfall trapping, Karaman–Chappuis), and problems of ecological assignment. A number of additional species are therefore expected to be found in the future. The Towakkalak and Saripa cave systems are included in the Bantimurung-Bulusaraung National Park and are under efficient protection, but parts of the Maros karst outside the park are under serious threat, mainly from quarrying. Full article

In this study, we aimed to improve rice farmers’ productivity and profitability in rainfed lowlands through appropriate crop and nutrient management by closing the rice yield gap during the dry season in the rainfed lowlands of Indonesia. The Integrated Crop Management package, involving recommended practices (RP) from the Indonesian Agency for Agricultural Research and Development (IAARD), were compared to the farmers’ current practices at ten farmer-participatory demonstration plots across ten provinces of Indonesia in 2019. The farmers’ practices (FP) usually involved using old varieties in their remaining land and following their existing fertilizer management methods. The results indicate that improved varieties and nutrient best management practices in rice production, along with water reservoir infrastructure and information access, contribute to increasing the productivity and profitability of rice farming. The mean rice yield increased significantly with RP compared with FP by 1.9 t ha⁻¹ (ranges between 1.476 to 2.344 t ha⁻¹), and net returns increased, after deducting the cost of fertilizers and machinery used for irrigation supplements, by USD 656 ha⁻¹ (ranges between USD 266.1 to 867.9 ha⁻¹) per crop cycle. This represents an exploitable yield gap of 37%. Disaggregated by the wet climate of western Indonesia and eastern Indonesia’s dry climate, the RP increased rice productivity by 1.8 and 2.0 t ha⁻¹, with an additional net return gain per cycle of USD 600 and 712 ha⁻¹, respectively. These results suggest that there is considerable potential to increase the rice production output from lowland rainfed rice systems by increasing cropping intensity and productivity. Here, we lay out the potential for site-specific variety and nutrient management with appropriate crop and supplemental irrigation as an ICM package, reducing the yield gap and increasing farmers’ yield and income during the dry season in Indonesia’s rainfed-prone areas. Full article

Clean water is an unlimited and sustainable need that must be fulfilled every day and meet an appropriate standard in terms of quantity and quality. The research objective in this study was to analyze the quality of water in thirty freshwater springs and twenty four brackish springs in the karst area of Buton Tengah Regency to achieve sustainable water resource management. Data on the quality of freshwater springs and brackish water springs chemically and biologically have been analyzed in the biology laboratory of FMIPA Universitas Halu Oleo, then the results are compared with the standards for water quality contained in the regulations of the Minister of Health and Government Regulation of the Republic of Indonesia. The results showed that the freshwater springs in Talaga Raya District exceeded the water quality standards for hardness parameter, while the brackish springs in Mawasangka Tengah, Mawasangka Timur, Lakudo, and Mawasangka Districts has exceeded the water quality standards for parameters of total dissolved solids, hardness, and chloride. However, these parameters are relatively easy to overcome so that the use of freshwater springs can qualify as drinking water, while the use of brackish springs should be used to meet domestic non-drinking water needs. Full article

Although the exploration of mineral resources and industry can promote economic development, it can also threaten the resilience and well-being of the environment, health, ecosystems, and the comfort of surrounding communities. Therefore, business entities, through corporate social responsibility (CSR) or other activities, can function to balance negative impacts and strengthen sustainable development that can increase the resilience and welfare of the surrounding community. This study aims to develop a resilience model of the local farming community resilience (FCR), which supports the sustainability of agricultural development. The research will be carried out in a community in Southeast Sulawesi, Indonesia. This study measures the resilience of the farmers’ community. To obtain models and instruments that are valid and reliable, the instrument is tested on 295 respondents in 10 villages adjacent to the nickel mining industry using the Partial Least Square-Structural Equation Modelling (PLS-SEM). Out of the 17 items, five dimensions (e.g., economic, social capital, environmental, community competence, and information and communication) are proposed to measure the FCR. Thus, this work presents a complete scale development and can provide policies for governments, particularly in Indonesia. Moreover, the FCR scale might be utilized by different entities (e.g., NGOs, open experts and social group media) to determine the view of genuine clients regarding the association’s CSR execution. Full article

Extraction of limonite ore using dissolved SO₂–air is an alternative hydrometallurgical method for nickel recovery. This process is carried out at atmospheric pressure and is shown to have good selectivity of nickel over iron, but with a low recovery yield. The literature refers to the application of alkali roasting as pretreatment in laterite ore leaching to increase nickel recovery. Thus, this study aims to apply the combination method of alkali roasting and leaching to extract nickel from limonite ore (1.33% Ni, 46.61% Fe) from the Southeast Sulawesi region. Three alkali compounds were included in the study (NaOH, Na₂CO₃ and Na₂SO₄). The batch-leaching process was carried out at pH 1 and 3 and temperatures of 55 and 80 $°$C for 180 min. The leach liquors were sampled at 15, 60, 90 and 120 min, and concentrations of the extracted metals were measured by Atomic Absorption Spectrometry (AAS). A mineralogy characterization of the raw ore and its residue after leaching was undertaken by using X-Ray Diffraction (XRD), while the thermal decomposition behavior of the ore was characterized by Thermogravimetry Analyzer (TGA)/Differential Scanning Calorimetry (DSC). The addition of Na₂CO₃, Na₂SO₄ and NaOH in the ore pretreatment increases nickel recovery from 14.80% without alkali roasting to 23.99%, 28.15% and 39.22%, respectively. The optimum extraction condition for nickel recovery is at pH 1 and a temperature of 80 $°$C. However, the highest Ni/Fe selectivity of 24,947 is obtained at pH 3 and a temperature of 80 $°$C, preceded by roasting in the absence of alkali. Compared to other hydrometallurgical processes, the process studied in this work exhibits lower recovery, but provides an alternative to extract nickel from low-grade limonite ore. Full article