Moderate Zones Research Articles

The Impact of Detrital Minerals on Reservoir Flow Zones in the Northeastern Bredasdorp Basin, South Africa, Using Core Data

The present study uses core data to group reservoirs of a gas field in the Bredasdorp Basin offshore South Africa into flow zones. One hundred and sixty-eight core porosity and permeability data were used to establish reservoir zones from the flow zone indicator (FZI) and Winland’s methods. Storage and flow capacities were determined from the stratigraphy-modified Lorenz plot (SMLP) method. The effects of the mineralogy on the flow zones were established from mineralogy composition analyses using quantitative X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results reveal five flow zones grouped as high, moderate, low, very low, and tight reservoir rocks. The high flow zone is the best reservoir quality rock and has porosity and permeability values ranging from 12 to 20% and 100 to 1000 mD. The high and moderate zones contribute more than 60% of each well’s flow capacities. The moderate and low flow zone extends laterally to all the wells. The tight flow zone is an impervious rock and has the lowest rock quality with porosity and permeability values less than 8% and 1 mD, respectively. This zone contributes less than 1% to flow capacity. The impact of minerals on flow zones is evident in plagioclase and muscovite content increases. An accompanied decrease in quartz content is observed, which implies that low plagioclase content ≤4% and muscovite content of ≤1% corresponds to the low, moderate, and high flow zones, while plagioclase content of ≥4% and muscovite content of ≥1% belong to the tight flow zone. Consequently, the quantity of plagioclase and muscovite can be used as a proxy to identify better quality reservoir rocks. The diagenetic process that reduces the rock quality can be attributed to quartz overgrowth and the accumulation of mica flakes in the pore spaces. In contrast, the fracture in the high flow zone is the reservoir quality enhancing process. The flow zones are generally controlled by a combination of facies and diagenetic factors.

Efektivitas Antibakteri Staphylococcus aureus Dari Sediaan Sabun Mandi Cair Dari Ekstrak Etanol Daun Beluntas (Pluchea indica L)

Beluntas leaves (Pluchea indica L.) is one of the plants that contain compounds such as flavonoids, alkaloids, tannins and saponins. This compound can be used to inhibit the growth of Staphylococcus aureus bacteria. The aim of this research is to make liquid bath soap preparation from ethanol extract beluntas leaves (Pluchea indica L.) and to know anthibactery activity against Staphylococcus aureus bacteria. The formula used in making liquid soap ethanol extract beluntas leaves (Pluchea indica L.) made with variation concentration 0%, 3%, 6% and 9%. The activity of extract of liquid soap beluntas leaves against the bacteria staphylococcus aureus by diffusion method using a concentration variation of 0%, 3%, 6% and 9% having the diameter of the inhibition zone respectively 4,48 mm, 6,23 mm and 7,3 mm. Statistical tests using parametic SPSS tests were carried out, the results obtained at concentrations of 6% and 9% had te same diameter inhibition zone, which was included in the category of moderate inhibition zone.

Dominant species losing functions to salinity in the Sundarbans Mangrove Forest, Bangladesh

Globally, mangrove forests are deteriorating due to several natural and anthropogenic factors such as sea level rise, habitat fragmentation, over-exploitation, pollution, etc. Sea-level rise - driven salinity would influence the functional activity of dominant species by declining their structure and functions, which is not well understood. Therefore, we tried to understand the increased salinity impact on the structures and functions of two identified dominant mangrove species (i.e., Excoecaria agallocha and Heritiera fomes) in the Sundarbans Mangrove Forest (SMF), Bangladesh. We test our hypothesis that salinity significantly retards the functions of dominant species structure and functions by evaluating two consecutive years of inventory data from 60 permanent sample plots (100 m2 each) established in three distinct salinity zones in the SMF. The study revealed that structural parameters of dominant species such as tree height, diameter at breast height (DBH), and basal area decreased in higher saline zones than in less saline zones. E. agallocha and H. fomes stored more biomass and carbon in less saline and moderate saline zones compared to high saline zone. Besides, functional variables such as above-ground biomass carbon and total biomass carbon decreased with salinity for both dominant species. This study demonstrated that salinity shapes dominant species by declining their height, DBH, growth, etc., which indicates salinity is a critical discriminating variable for losing species’ stand structures and functions. This information is critica to determine the physiological response of dominant species across the globe, which is crucial to predicting future climate change impacts such as sea-level rise.

Comprehensive energy efficiency study of different climate -adapted BIPV roof forms in single-family houses for five climate zones of China based on PV energy substitution rates (PVESR)

As a type of energy production construction, building integrated photovoltaics (BIPV) roofs are contributing for achieving NZEB goals. Considering building sites’ climate attributes with possible size of PV systems can help to reduce the initial investment and energy consumption of building operation and maintenance. This paper investigates the energy production and energy consumption patterns of single-family houses, which is designed to evaluate the comprehensive energy efficiency of BIPV roofs to meet energy demands by photovoltaic energy substitution ratio (PVESR) calculations. Five typical cities were selected, corresponding to the five climate zones in China; eight forms of BIPV roofs were developed according to single-family houses’ common scale and spatial characteristics. The results show that (1) The PVESR varies significantly between different climate zones and different forms of BIPV roofs, so pre-survey of BIPV roof application sites and comparison of roof forms are relevant in preliminary architecture design. The climate zones where energy balance can be achieved are hot-summer & warm-winter zones, hot-summer & cold-winter zones and moderate zones, and the average PVESR based on the eight roof prototypes are 0.987, 1.136 and 2.272 respectively; the corresponding PVESR for cold zones and severe cold zones are 0.807 and 0.475. (2) The peak and trough values of capacity and energy use are not exactly matching in the five climate zones, especially in severe cold zones, cold zones and hot-summer & cold-winter zones’ winter. (3) The high heating demand in winter is the main reason for the failure to balance BIPV production and energy consumption in severe cold zones and cold zones. The comprehensive energy efficiency evaluation method of BIPV roofs proposed in this paper can provide data support and application guidance for form design and size determination of BIPV roofs in five climate zones in China.

A GIS-based assessment of active tectonics from morphometric parameters and geomorphic indices of Assam Region, India

Assam region is mainly formed by the deposit and erosion process of the Brahmaputra River. The frequency of seismic events results in landform deformation, which highly influences the drainage basin pattern and causes drainage anomalies, having a subsequent effect on the flood distribution pattern. In the present study, morphometric parameters and geomorphic indices for the Assam region are derived from SRTM DEM data of 30 m resolution using GIS to characterize the tectonic activity, which in turn influences the drainage pattern. The indices are classified into three tectonic activity classes, and the average of the classes is combined to generate the indices of relative active tectonics (IRAT). The four classes of IRAT are defined for the study area as (i) very high; Class 1 (1.57–1.80), (ii) high; Class 2 (1.81–2.06), (iii) moderate; Class 3 (2.07–2.26), and (iv) low; Class 4 (2.27–2.30). Class 1 corresponds to basins 1 and 6. Basins 2, 4, and 5 fall under Class 2. Class 3 consists of basins 7, 8, and 9, and Class 4 comprises basins 3 and 10. Results show that most of the study area lies in very high to moderate active tectonic zones and the identified zones are consistent with significant faults and thrusts present in the basins. The combined approach of GIS-based morphometric and geomorphic study allows for identifying deformed landforms resulting from active tectonics. The results can also be employed for the development of watershed management and sustainable land use planning.

Landslide susceptibility zone in steep slope landscape at Gunung Kidul Regency, southeast part of Yogyakarta, Indonesia

Gunung Kidul is located in Central Java Province, Indonesia. which is vulnerable to geological hazard such as floods and earthquake. However, it is also susceptible to landslide in some areas of Gunung Kidul which contributes to damage and loss. The study area is covers sub districts such as: Patuk, Gedangsari, Nglipar, Ngawen, Playen. It covers an area of 1,485.36 km2 and had a population of 747,161 at the 2020 Census. This research aims to produce a landslide susceptibility map, construct the detailed geological map, consider geomorphology aspect, lithology aspect, soil-rock masses, hydrogeology/groundwater aspect, structural geology aspect, land use. The parameters that caused the occurrence of landslide were determined and the landslide susceptibility map was produced using Weightage Overlay Method (WOM) in ArcGIS software. Results showed that the susceptibility map was classified into three zones which is low, moderate and high zone. The factor that triggered the landslide were identified which is heavy rainfall intensity and earthquake. As a conclusion, the ability to detect landslide susceptibility led to a better understanding of landslide mechanisms for the research area, thus leading to an enhanced identification of the most likely failure sites within a landslide-prone area.

Preliminary Study of Landslide Hazard in Kutai Kartanegara Regency, East Kalimantan using Digital Elevation Model

The Kalimantan Island is part of the Sundaland crust, namely the Eurasian Continental Plate. The plate is moving to the southeast colliding with the Indo-Australian plate which is moving north. Whereas for Kutai Kartanegara Regency in the Kalimantan Island position is far from the collision zone, so it is relatively stable tectonically. This is important to research that is, due to tectonic processes that occurred earlier, resulting in the formation of geological structures, especially faults. The purpose of the study was to determine the morphotectonic and landslide hazards in the Kutai Kartanegara Regency, where this research was carried out quantitatively with data collection techniques, then analyse landslide hazards based on data; DEM (Digital Elevation Model) including the slope, slope direction, and slope length for vulnerability analysis, geological data from Regional Geological Maps, which include rock formations, distances from faults data and administrative boundary spatial data in the form of vector GIS for the preparation of landslide hazard maps. The result showing Kutai Kartanegara predominantly categorized as moderate to high hazard zone. The low hazard zone covering 9.88% area, moderate hazard zone covering 35.81% area, and 54.31% area is high hazard zone of landslide. The analysis showing that the hazard of the research area consist predominantly sedimentary rocks and controlled by structural geology identified as thrust fault, strike slip fault, and fold which include in Anticlinorium Samarinda. Those lithology and geological structure features along with the slope are identified as controlling factor to the landslide hazard in the research area.

Gully erosion vulnerability modelling, estimation of soil loss and assessment of gully morphology: a study from cratonic part of eastern India.

A highly visible form of soil erosion is gully, a significant geomorphological feature, resulting from water erosion and causing land degradation and deterioration. In arid and semi-arid environment, gully erosion is conceived as an important source of sediment supply washing out the top fertile soil and exposing lower soil layers. The present study is conducted on the lateritic terrain of Rupai watershed of eastern plateau fringe of India, where water erosion is a serious concern. In order to prepare a gully erosion vulnerability mapping, the analytical hierarchy process (AHP) model coupled with geospatial technology is adopted taking into account thirteen bio-physical factors. It is revealed that around 49% area of the watershed belongs to high to very high gully erosion vulnerability zone (GEVZ) followed by moderate risk zone of 31.64%. This model is validated performing an accuracy assessment, which is calculated to be 90.91%, and the value of Kappa co-efficient is 0.86. It is imperative to estimate the average annual soil loss alongside of delineating GEVZ; thus, the revised universal soil loss equation (RUSLE) model is used with geospatial technology. It unveils that the average estimated soil loss of the watershed varies from < 15 to 431 t ha-1 y-1. Around 29% of the study area experiences high to very high (57 to > 147 t ha-1 y-1) soil erosion risk, where 68% area endures low level of soil erosion risk (< 15 t ha-1 y-1). The study of gully morphology depicts gully depth ranging from < 1 to 5m (small to medium gully) with V and U shapes. Results obtained from this study may help in planning and management of land use and soil erosion conservation.

Match characteristics of professional outfield amputee soccer players during official amputee soccer matches

Objective: The objective of this study was to investigate physiological responses and movement profiles of amputee soccer players during official matches. Material and Methods: Five outfield amputee soccer players with a 9.20±0.81 years of amputee soccer experience (age 28.60±5.32 years; height 1.71±0.05 m; body mass 71.54±9.39 kg) volunteered for this study. Physiological responses [blood lactate (BLa), heart rate (HR) and ratings of perceived exertion (RPE)] and activity profiles [peak speed, total distance covered (TD), TD at five speed categories (SC), percentages of TD at five SC and time spent in four maximal heart rate (HRmax) zones] were analyzed during seven official amputee soccer matches. Results: Mean game BLa, RPE, HR and HRmax were 5.58±1.63 mmol.L-1, 9.43±2.62, and 151.77±16.05 bpm and 180.74±9.23 bmp, respectively. HRmax was higher in the first half than in the second half (p=0.02). Players covered 102.62±7.24 m.min-1 and this did not change between the halves during amputee soccer matches (p=0.40). TD at very low SC was 73.86±0.57 m.min-1 whereas TD at very high SC accounted only for 0.24±0.04 m.min-1. Similarly, the percentage of the TD at very low SC was 70.18±10.30% and the percentage of the TD at very high SC was 0.24±0.04%. Amputee soccer players spent ~31 min and ~15 min at high intensity and moderate HRmax zones, respectively. These accounted only about ~5 min at very low and low intensity HRmax zones during whole matches. Conclusion: These results showed that amputee soccer played at the professional level is a high-intensity exercise, which could be used to prescribe amputee soccer specific training regimes.

Groundwater potential zones identification and validation in Peninsular India

ABSTRACT Groundwater mapping is essential for meeting the water requirement of people. Identification of groundwater potential zone was attempted for a watershed located in Kanchipuram district, Tamil Nadu, India. The Landsat 8 and Landsat 5 data were used for land use/land cover analysis. For delineating groundwater potential zone, total seven thematic layers namely drainage density, slope, geology, soil, geomorphology, rainfall, land use/land cover and observed groundwater levels were considered during the analysis. Afterwards thematic layers were converted into raster using GIS platform. Further, after assigning weights and ratings to each thematic layer, overlay analysis was applied and total five zones were delineated as very good, good, moderate, poor, and very poor. The majority of area has moderate groundwater potential zone. The potential zone map was also validated using ROC method. The map of 2005 shows a highest accuracy compared to rest year maps.

Urban Comprehensive Carrying Capacity and Development Order: A “Pressure-Capacity-Potential” Logical Framework

Urban comprehensive carrying capacity determines the scale and development direction of a city and is an important factor in the optimization of main function areas, the arrangement of urban development order, and the demarcation of urban development boundaries in China’s new national spatial planning system. Using the constructed “pressure-capacity-potential” model as a theoretical basis, this study combines human factors and natural factors and calculates the urban carrying capacity index by means of multi-factor weighted summation, graded assignment, stepwise correction, and subsection variable weight. From the perspective of the integration and coordination of “three forces,” urban development rules are established, and an urban development order based on the framework of “three districts and six types” is put forward. The results reveal four key findings. First, the “pressure-capability-potential” conceptual model analyzes the urban carrying capacity from the perspective of the integration of externality and internality, which can effectively support the orderly arrangement and rational layout of urban development. Second, the urban carrying pressure of Shandong province is general, and the urban carrying capacity is high. The results also showed that the urban carrying potential is low and the urban comprehensive carrying capacity is high. Third, in the “3+6” urban development pattern of Shandong province, priority development and key development zones are the main areas. For the most part, these zones are distributed in the Jiaodong Peninsula, the Jinan–Tai’an–Jining development zone, and the surrounding areas of Weifang, Linyi, Liaocheng, and Heze. Moderate development zones are concentrated in Nansi Lake and the Yellow River Delta. Fourth, the urban development in Shandong province is mainly restricted by landform, water resources, environmental capacity, and geological disasters. Under the premise of ensuring resource conservation and environmental friendliness, using policies and engineering measures to revitalize stock space is an effective way to foster urban development in the 14th Five-Year Plan period. This study can provide reference for the evaluation of urban comprehensive carrying capacity and the establishment of development order in Shandong province and other similar areas.

PROBABILISTIC PERFORMANCE ASSESSMENT OF EXISTING RC BRIDGE IN A MODERATE SEISMIC ZONE

Observations from previous earthquakes indicated that substandard bridges in different parts of the world could be severely damaged or even suffer a collapse under strong earthquakes. Potential damage to substandard and pre-seismic code bridges can be identified using detailed inelastic assessment procedures, which supports the selection of suitable seismic mitigated approaches. In this study, a five-span simply supported typical bridge located in the UAE, which is selected as a case study representing moderate seismic zones, is investigated numerically for seismic vulnerability. The fiber-based modeling approach adopted in this study is verified using a bridge bent tested in another study using quasi-static cyclic loading experiments. A three-dimensional (3D) model is developed to consider the bridge components' geometric non-linearities and material inelasticity, including multi-column piers, superstructure, gaps, and bearings. A set of diverse input ground motions are selected, scaled, and applied to the bridge model with increasing intensities to develop fragility curves. Lower strength and higher deformation demands are observed in the longitudinal direction of the bridge compared to its transverse counterpart. The fragility analysis also confirmes the higher vulnerability in the longitudinal direction. The study highlights the pressing need for seismic retrofit to ensure the post-earthquake functionality of substandard bridges in the study region.

Development of a web-based geospatial intelligent decision support system for control of herders and farmers crisis in Benue State Nigeria

The biggest challenge in Nigeria today is herder-farmer conflict particularly in Benue State Nigeria. This study developed a web-based geospatial decision support system for control and management of herders/farmers crisis in Benue State. Landsat 5 TM (1989), Landsat 7 ETM+ (2004) and Landsat 8 (2019) were pre-processed and classified. The study revealed that forested areas had depleted by -4.17% between 1989 and 2004 and -2.20% between 2004 and 2019. Farmland had an increase of 34.01% between 1989 and 2004 and 17.92% between 2004 and 2019 and grassland had -7.12% between 1989 and 2004 and -3.89% between 2004 and 2019. The study also revealed five conflict zones with Agatu in Very high conflict zone with 88 -230 clashes, the high conflict zone included Guma, Gwer West and Logo with 41 – 87 clashes, the moderate conflict zone include Gwer East, Ohimini Markudi and Okpokwu with 16 – 40 clashes, the low conflict zone include Otukpo with 3 – 15 clashes, the very low conflict zone include Apa, Ado, Obi, Oju, Kwande, Ukum, Katsina Ala, Gboko, Buruku, Tarka, Ushongo, Konshisha, Ogbadibo, and Vandeikya with 0 -2 clashes. The potential sites for grazing reserves were determined using the Analytical Hierarchy Process (AHP). The results revealed a total area of 8361.46hectares (0.27%) of the total land mass as potential grazing reserves, covering 18 local government areas. A database of the potential areas for grazing reserves was implemented in QGIS software. The study recommended potential areas for establishment of grazing reserves in Benue State.

Landslide Susceptibility Mapping of Menoreh Mountain Using Logistic Regression

Menoreh mountain is one of the priority areas developed for tourism and to support sustainable development, it must pay attention to disaster aspects, one of which is landslides. The map published by Center for Volcanology and Geological Hazard Mitigation of Indonesia (PVMBG) has a regional scale, so it is necessary to have a more detailed landslide susceptibility map in the Menoreh Mountains. Identification and evaluation of the landslide conditioning factor were done using logistic regression so that the zonation of the probability of landslide susceptibility can be made. The data was used from field observation conducted at 372 locations including 129 locations where landslides occurred and from a local disaster management agency (BPBD) of 200 landslide locations. Significant landslide conditioning factors include slope, lithology, distance to lineaments, distance to river, and distance to road. The research area is divided into three susceptibility zones classified into low landslide susceptibility zone (0-0.33) covering 39.82%, moderate landslide susceptibility zone (0.34-0.66) covering 25.86%, and high landslide susceptibility zone (0.67-1.00) covering 34.31% of the whole area. Analysis using the logistic regression method has a model prediction accuracy rate of 90.5%, which means that it can predict landslide occurrence in the Menoreh Mountains accurately.

Improvement of Ecological Risk Considering Heavy Metal in Soil and Groundwater Surrounding Electroplating Factories

Heavy metals in groundwater and soil are toxic to humans. An accurate risk assessment of heavy metal contamination can aid in environmental security decision making. In this study, the improved ecological risk index (RI) is used to comprehensively investigate the influence of heavy metals in soil and groundwater within electroplating factories and their surrounding regions. In the non-overlapping area, the RI of soil and groundwater is computed individually, and in the overlapping area, the greater RI of soil and groundwater is employed. Two typical electroplating factories are used to examine the heavy metal distribution pattern. The heavy metal concentrations are compared between Factory A, which is in operation, and Factory B, which is no longer in operation, in order to analyze the heavy metal concentrations and associated ecological risks. Heavy metals continue to spread horizontally and vertically after Factory B was closed. Heavy metal concentrations in groundwater surrounding Factory B are substantially greater, and the maximum concentration exists deeper than in Factory A. Because Cr, Cu, and Hg in soil contribute significantly to the RI, the primary high RI region is observed at Factory A and the region to the southwest. The RI of Factory B demonstrates a broad, moderate risk zone in the west and southwest.

Analysis of the distribution characteristics and driving factors of land use conflict potentials in the Bohai Rim coastal zone

Land use in coastal zones faces the challenge of overlapping and competing among agriculture, construction, and ecological functions. Identifying land use conflicts (LUCs) and exploring their driving factors are the premise to alleviate the problem of ‘competing for land’. Firstly, this study constructed a multi-objective evaluation system from three perspectives: agricultural land, construction land, and ecological land suitability. Then, the types of LUC were divided based on the suitability of spatial combination. Finally, we analyzed the spatial distribution characteristics and the main driving factors of LUCs in the Bohai Rim region of China. In addition, we discussed the situation of LUCs along the sea-land direction. Results showed an obvious spatio-temporal mismatch in the spatial layout of agricultural land, construction land, and ecological land suitability in coastal zones. On a grid-scale, high, moderate, and low conflict zones accounted for 17.50%, 52.68%, and 4.64%, respectively. Moreover, there were significant differences in different forms of conflict. At the country scale, conflict intensity showed a regional distribution characteristic of "high in the South and low in the North", with significantly spatial positive correlation. In addition, both natural and socio-economic factors had significant effects on the spatial clustering distribution characteristics of LUCs. We recommend that land policymakers adopt different governance strategies according to conflict degree, spatial distribution, manifestation, and influencing factors.

Time-domain analysis of quarter-circle shaped oscillating water column device

The present work investigates the working mechanism of the quarter-circle shaped (QCS) OWC-WEC in the time-domain. Several parameters relevant to the functioning of an OWC-WEC are examined for various wave and device parameters. The free surface elevation is presented for a different instant of time to show the functioning of the OWC device in the time domain. The study shows that the OWC-WEC can capture and hold the wave energy for an extended period of time. The resonances appear in the efficiency curve in the longwave zone for higher chamber length and lip wall’s draft. Moreover, the peaks in the efficiency curve occur in the short and moderate wave zones as a result of sloshing effects. The device efficiency becomes higher when the lip wall’s immersion depth is more in the longwave zone. An opposite trend is reported for the moderate and shortwave zone. It is mentioned that the time-domain analysis can simulate the free surface elevation accurately as compared to the frequency domain analysis. In addition, the quarter-circle shaped front wall perform an appreciable role in enhancing the stability of the device.

PROBABILISTIC PERFORMANCE ASSESSMENT OF EXISTING RC BRIDGE IN A MODERATE SEISMIC ZONE

Observations from previous earthquakes indicated that substandard bridges in different parts of the world could be severely damaged or even suffer a collapse under strong earthquakes. Potential damage to substandard and pre-seismic code bridges can be identified using detailed inelastic assessment procedures, which supports the selection of suitable seismic mitigated approaches. In this study, a five-span simply supported typical bridge located in the UAE, which is selected as a case study representing moderate seismic zones, is investigated numerically for seismic vulnerability. The fiber-based modeling approach adopted in this study is verified using a bridge bent tested in another study using quasi-static cyclic loading experiments. A three-dimensional (3D) model is developed to consider the bridge components' geometric non-linearities and material inelasticity, including multi-column piers, superstructure, gaps, and bearings. A set of diverse input ground motions are selected, scaled, and applied to the bridge model with increasing intensities to develop fragility curves. Lower strength and higher deformation demands are observed in the longitudinal direction of the bridge compared to its transverse counterpart. The fragility analysis also confirmes the higher vulnerability in the longitudinal direction. The study highlights the pressing need for seismic retrofit to ensure the post-earthquake functionality of substandard bridges in the study region.

Antibacterial activity of ethanolic Spirulina platensis extract-water soluble chitosan nanoparticles

Spirulina platensis is a microalga containing bioactive compound as antibacterial activity. The antibacterial compound from Spirulina can be used to treat bacterial infections on the skin such as acne. However, enhancement penetration of bioactive compounds through the skin was needed. The objective of this study was to determine bioactive compounds from Spirulina, synthesize Spirulina extract-water soluble chitosan nanoparticles using the ionic gelation method, and measure the antibacterial activity of Spirulina extract and its nanoparticles. For the synthesis of the nanoparticles, differences of Spirulina extract concentrations were used, including 3.25, 7.5, and 15 mg/mL. The yield of ethanolic Spirulina extract was 13.87±4.16% with the bioactive components of saponins, tannins, steroids, and phenols. The Spirulina extract-loaded chitosan nanoparticles were successfully fabricated with a nano-range size and narrow polydispersity. The amount of loading of Spirulina extract has affected the size and dispersion of nanoparticles. The antibacterial activity of nanoparticles showed higher than pure Spirulina extract only through Staphylococcus aureus and Pseudomonas aeruginosa, classified as moderate inhibition zones (5-10 mm). These suggested that nanoencapsulation could increase extract uptake on bacteria cells. The ethanolic Spirulina extract-chitosan nanoparticles have a potency for antibacterial agents on cosmeceutical products.

Synthesis of Antibacterial and Biodegradable Bioplastic Based on Shrimp Skin Chitosan and Durian Skin Cellulose with the Microwave Assistance

This study aimed to obtain the best composition in the synthesis of antibacterial bioplastics made from chitosan from shrimp skin (SS) and cellulose from durian skin (DS). The research method began with the isolation of chitin from SS. Then it was deacetylated using a microwave (MW) at 60 °C for 15 minutes at 400 watts of power in an alkaline solution. The extraction of cellulose from DS through delignification using the MW for 20 minutes, 300 watts of power in Na2SO3 solution. Synthesis of bioplastics is made from variations in the composition of chitosan (8, 12 and 16% w/w), cellulose and glycerol as a plasticizer. The characterization of bioplastics with FTIR obtained functional groups O–H, C–H, C=O, C–N and N–H amines, and SEM characterization obtained bioplastic has fibre and pore size 15.429 µm. The best bioplastic characteristics were the composition of 12 % chitosan, with tensile strengths of 13.28 Mpa, water resistance of 79 % and the ability to degrade 52.67% after 15 days have met international plastic standards (ASTM 5336). The antibacterial activity of bioplastics against Escherichia coli and Staphylococcus aureus with the Disc diffusion method showed the presence of moderate zones category of inhibition so that the resulting bioplastics can be recommended as food packaging that is environmentally friendly and antibacterial.