bluuebunny/crossref_metadata_2025 huggingface dataset:
Shear capacities of reinforced concrete interior beam-column joints subjected to cyclic loading
Authors: Maulana H , Amal I , Iqbal W , Thamrin R , Zaidir  , Kurniawan R
Published: May 2023

The primary focus of this research is the experimental investigation of internal RC beam-column joints with cyclic loads. There were two interior RC beam-column joints test specimens made without shear reinforcement. The longitudinal reinforcement ratio of the beams served as the study’s test variable. The specimen test results were compared to the theoretical capacity given in SNI 2847-2019 after that. The test revealed the following: (a) shear and flexural beam capacities; (b) shear and flexural column capacities; and (c) shear capacities of joints. The results showed that there was a significant impact on the shear capacity of the beam-column joint as a result of the variation in the reinforcement bars of the beam. After the longitudinal reinforcement bars of the beam yielded in both instances, the degradation of the beam-column joint occurred. A sharp decline in the load value that the specimen can support serves as evidence.
Cracks evaluation at a pier of a curved box girder bridge during its balanced cantilever construction sequence
Authors: Hidayat N H , Purnomo H
Published: May 2023

In urban area, modern role of bridges is to connect two or more locations. In that area, it is often to construct long span road crossing curved integral bridges consisting of several spans. In this study, the same type of bridge which is located at the intersection of an existing road and an elevated toll road in Jakarta showed cracks at one of the piers during construction of bridge segments. Construction time started from the beginning of 2016 until the end of 2018. Observations were done after the occurrence of cracks by installing strain gauge sensor at the lower part of the pier. Strain from the strain gauge is not only influenced by the construction activities but it is also influenced by the temperature of the surrounding environment. Construction staging analysis using MIDAS Civil software was conducted to evaluate the cracks. Numerical strain evaluation was done by considering the temperature effect taken from the measurement. Both stress which is calculated from the strain obtained by the measurement and construction staging analysis are in good concordance. Using the allowable stress limit for both obtained stress, the actual condition at the pier were verified.
Seismic assessment and retrofitting of the old URM railway station building in Padang City, Indonesia
Authors: Fauzan  , Jauhari Z A , Agista G A , Carol N D , Putra Y S
Published: May 2023

The train is one of the means of land transportation between cities that is in demand by all levels of society. As a mass transportation capable of transporting passengers and goods in large quantities and cheaply, the train can be immediately implemented in Padang City, especially from Padang to the Minangkabau International Airport (BIM) in Pariaman regency. To support the program, re-activating the old train stations that are no longer in use such as Pulau Aer Station, should be done by the directorate general of transportation, Indonesia. This station building is located in Southern part of Padang City, Indonesia. This station building is an old unreinforced masonry (URM) building, which had heavily damaged after the earthquake on September 30th, 2009. Before re-activating this station, a building assessment and retrofitting of this station building are required. The building assessment is carried out both visually and through structural analysis, while the building retrofit is designed using the ferrocement layer method. The analysis result shows that the shear stress on the walls of the retrofitted building is able to withstand the working loads, including the earthquake load.
Spatial modelling of tsunami hazards and their exposure to settlements in Ambon City
Authors: Sugandhi N , Supriatna  , Kusratmoko E , Rakuasa H
Published: May 2023

Ambon City is an area that has the highest disaster risk index in Maluku Province. The direction of development of residential areas in Ambon City tends to be coastal areas which of course will have an impact on the risk of tsunami hazard. This study aims to spatially model the tsunami hazard and its exposure to settlements in Ambon City. The research variables consisted of land height, slope, distance from the river, and distance from the shoreline. This study uses an overlay technique on the variables that have been assessed and analysed using a Geographic Information System approach. The results of the study show that the tsunami hazard in Ambon City is dominated by a low level of tsunami susceptibility which has a wider area than the medium and high tsunami vulnerability classes, this is because 77.32% of the Ambon City area is at an altitude of > 64 m while the tsunami exposure level in settlements in Ambon City are nominated with a high level of vulnerability with an area of 2,835.33 ha.
Study of Ground Motion Models Selection to the Concrete Frame Building Damage Probability using the 2006 Yogyakarta Earthquake Scenario
Authors: Muntafi Y , Nojima N , Ikramullah I
Published: May 2023

Damage probability assessment using the ground motion prediction equation (GMPE) models is paramount in seismic risk analysis. Several GMPE models have been proposed and developed worldwide. However, it has its parameters and gives different spectral acceleration results. The study aimed to investigate the impact of GMPE model selection on the estimation of building damage probability due to the scenario of Yogyakarta earthquake. In the beginning, we modeled the 3D-concrete moment frame building, followed by conducting pushover analysis to determine the building responses and calculating the building damage probability based on HAZUS method to generate fragility curve and damage probability matrix. Five GMPE models were employed in this study. The results revealed that for the modeled structure, the GMPE of Ambraseys et al. (1996) gave the highest value of the peak building response compared to the GMPE of Sadigh et al. (1997), Boore et al. (1997), Spudich et al. (1999) and Idriss (2002). The probability of moderate, extensive, and complete damage levels was also dominated by the GMPE of Ambraseys et al. (1996), which indicated that in this case, the use of this GMPE would produce the most severe damage probability value.
Tsunami current and its impact on inundation depth in the coastal areas of West Sumatra – Indonesia
Authors: Daoed D , Syukur M , Ariya P S
Published: May 2023

The influence of cities that are in coastal areas and prone to earthquakes is very likely to be hit by tsunami waves or currents. The city of Padang is one of the cities in Indonesia which is located along the Indonesian sea coast and is also an earthquake-prone area so it has the opportunity to experience tsunami waves. Efforts to inhibit wave propagation are mostly carried out by using walls on the beach or multi-story buildings. However, in small towns or villages you rarely find multi-story buildings, there is only drainage parallel to the beach. Based on this, an experiment was carried out by imitating the existing conditions and changing the width of the drainage for the Purus and Ulak Karang Padang areas. The purpose of this study was to determine the effect of changing the drainage geometry on the tsunami current. The results showed that the drainage channel was wider, the greater the decrease in height and area of inundation or vice versa. It is recommended for stakeholders make adequate and safe drainage against tsunami flows.
The influence of various parameters of physical and mechanical properties on susceptibility to liquefaction of sandy soils
Authors: Yuliet R , Silvy A L , Hakam A , Fauzan  , Mera M , Syuhada S
Published: May 2023

On September 30, 2009, there was liquefaction in the sandy soils around the coast of Padang city, which was triggered by an earthquake measuring 7.6 SR. Liquefaction causes land subsidence and lateral displacement of many buildings in Padang. The level of liquefaction vulnerability of Padang city is in the moderate zone based on qualitative methods; on the contrary, quantitative methods obtained a very high level of vulnerability to liquefaction. Based on this, quantitative methods by conducting geotechnical investigations in the field and laboratory tests are needed to determine the liquefaction potential. This study aims to determine the potential for liquefaction using quantitative methods based on testing the physical properties and mechanical properties of sandy soils in the laboratory. The standard for laboratory testing is the Indonesian National Standard (SNI), and soil sampling was carried out in seventeen areas. The results of the physical and mechanical properties, i.e., relative density (Dr), the particle size of the soil, and internal friction angle, showed that the sandy soils along the coast in Padang are poorly graded sand (SP). The sandy soils are dominated by fine sand with a very loose consistency, which has potential liquefaction.
Analysis of clay improvement as subgrade using Palm Oil Fuel Ash (Pofa)
Authors: Andriani  , Putra H G , Yuliet R , Maulana R , Marel S P
Published: May 2023

Road construction on clay soils often causes problems, because clay have a low bearing capacity and high swelling shrinkage values. Damage to roads on soft clay cannot be avoided; therefore, soil improvement is necessary. Soil stabilization is one of the efforts to improve soil properties, and the aim is to increase the bearing capacity of the soil. So far, the stabilizing materials commonly used for soil improvement are cement and lime. In study, oil shell waste in the form of palm oil fuel ash (pofa) will be used as a stabilizing agent. Pofa is one of the industrial wastes that contain a high percentage of silica (Si). The high silica (Si) content is beneficial for reducing the shrinkage properties of clay soils. Pofa ash content used in the study was 4%, 8%, 12%, 16%, and 20% of the total weight soil. The curing time of the sample was seven days with unsoaked and soaked (four days) conditions. The results of this study indicate that mixing pofa ash can increase CBR value and decrease the swelling value of clay.
Rock slope stability assessment using kinematic analysis at Gunung Batu, Lembang, West Java, Indonesia
Authors: Martireni A P , Sugianti K , Hermawan K , Tohari A , Wibawa S , Soebeowo E
Published: May 2023

Discontinuity plane in the Gunung Batu area associated with the geological structure of the activity of the Lembang fault has the potential to induce rock slope failure hazard to the surrounding residential areas. A series of slope stability analyses of the Gunung Batu was carried out using rock mass rating and kinematics analysis to assess the rock slope stability in the Gunung Batu and determine the rock failure type. According to the results of the rock mass rating, the outcrop of Gunung Batu is classified as a good rock. Meanwhile, kinematic analysis from three joint sets shows that the rock failure type is characterized by wedge and toppling failures. However, the analysis results of the Slope Mass Rating (SMR) indicate that the rock slope stability in Gunung Batu is considered in partially stable to stable condition.
Spatial and Temporal Analysis Prediction of Landslide Susceptibility Using Rainfall Infiltration and Grid-based Slope Stability Methods in West Bandung area of West Java-Indonesia
Authors: Hermawan Koko , Sugianti Khori , Martireni Antonina , Satrio Nugroho Aji , Yunarto
Published: May 2023

West Bandung, West Java, is an area with a high level of landslide susceptibility. Landslides in West Bandung occurred 142 times during rainfall in the last ten years. This paper presents the results of landside susceptibility modeling in the West Bandung area of West Java Province, Indonesia, considering the spatial characteristics of the rainfall data, slope and soil properties using the TRIGRS model. This research is based on conditions in the field in the form of landslide locations, soil engineering properties, soil thickness, Digital Elevation Model, and rainfall data. The effect of one-day antecedent rainfall intensity was considered in this study, i.e., 12 hours of antecedent rainfall. The results of the TRIGRS modelling showed that the intensity of rainfall antecedent of rainfall influenced the slope stability in the study area. The TRIGRS model results indicate that the predicted landslide susceptibility distribution agrees with the historical landslide events.
Effect of wet – dry cycles on CBR value and grain size distribution particle on compacted residual tuff soil
Authors: Syuhada S , Muzakky A H , Kurniawan R , Utami E T , Hayati J
Published: May 2023

Uncertain climate change is a natural phenomenon that is common nowadays. Soil is the result of weathering of rocks and climate change is one of the causes of this weathering. Residual soil is soil formed on top of the original rock layer. In addition to the parent rock, climate change also affects the residual soil, both in terms of grain size and shear strength. This climate change modeling was carried out by giving wet-dry treatment on residual tuff soil samples at the Institut Teknologi Sumatera (ITERA) which were compacted with a wet-dry cycle of 2 cycles, 4 cycles, 6 cycles, 8 cycles, and 10 cycles. From this treatment, it will be seen the change in gradation and the magnitude of the CBR value. The change in grain gradation is obtained which is calculated based on the concept of grain breakage, namely the Br value in each cycle of 15.89%; 21.51%; 25.35%; 32.01%; 36.28%. For the CBR values obtained for the initial conditions and each cycle are 50.74%, 40.34%; 29.763%; 25.16%; 22.825%; 20.580%. These results indicate that the longer the cycle occurs in the soil, the greater the change in grain gradation and the CBR value of the residual tuff soil. For this reason, the wet-dry process needs to be considered for the use of residual tuff soil as the subgrade of the road pavement.
Slope stability analysis at coal mining sites in Central Kalimantan
Authors: Prabowo H , Barlian E , Syah N , Sastra A T
Published: May 2023

Slope stability is an important factor in the planning and operation of open pits and mines. Currently the company has been mining up to a height of 20 meters. In the implementation of mining activities, the potential for landslides on the side walls of the slopes of sector X occurs on one of the slopes, namely at an elevation of +70 masl. The company made two design choices, one of which was confirmed by researchers in overcoming the potential for landslides. In carrying out slope analysis, information about the general properties of rock mass consists of testing the physical properties of rocks and testing the mechanical properties of rocks. The results of the safety factor analysis of the A-A cross-section with 2.476 saturated MAT (Stable) and dry MAT 3.159 (Stable), while the B-B cross-section with saturated MAT 2.161 (Stable) and dry MAT MAT is 2.771 (Stable). Meanwhile, for the two segments, A-A’ with saturated MAT of 2,459 (Stable) and dry MAT of 3,131 (Stable), while the B-B’ section with saturated MAT of 1,653 (Stable) and dry MAT of 2,464 (Stable). The researcher recommends using option 1 based on the safety factor value which shows a higher value.
Analysis of extreme wind wave based on weibull and fisher tippett I (gumbel) distribution
Authors: Pratiwi D , Pratama R , Fitri A , Lestari F
Published: May 2023

Extreme waves are an important factor in coastal structures both offshore structures and onshore structure design. However, due to the difficulty of measuring ocean waves, many areas still do not have measured wave height data. Data processing is required to transform the measured wind data into wind-wave value in order to solve this issue. This study aims to analyze extreme waves based on wind data from BMKG Panjang and BMKG Radin Inten II stations. For analysis of determination of extreme waves can be done by using Fisher Tippet Type I (Gumbel) and Weibull methods. The result show that Weibull method gives the higher value than Gumbel method, with the maximum percentage of 43.04% at the 2-year return period.
Adsorption using fly ash from stam power plants for acid mine drainage treatment
Authors: Siswati S , Pratama H , Giatman M
Published: May 2023

Acid mine drainage has a negative impact on the environment. Adsorption is an effective and efficient method for acid mine drainage treatment, besides that adsorption does not have a negative impact on the environment. This study aims to analyze the ability of fly ash from a steam power plant as an adsorbent in acid mine drainage treatment. Using experimental methods and batch adsorption mechanisms, with variations of adsorption parameters carried out including adsorbent dose, stirring time, and stirring speed. The test results show that fly ash is very effective in acid mine drainage treatment. Where there is an increase in pH and a decrease in the concentration of Mn and Fe metals in acid mine drainage to match the quality standard. The increase in pH was in the range of 6.3 to 7.4 with the highest effectiveness of 54.05%. In the reduction of Mnmetalthe highest effectiveness was 78.14%, while in Fe metal the highest effectiveness was 85.83%. Fly ash can be used and is very useful in reducing the impact on public health.
Performance Index of Anai I Irrigation-Area, Padang Pariaman
Authors: Junaidi  , Ulfa Jf Radhiatul , Mera Mas
Published: May 2023

The irrigation area of Anai River I which has an area of 6,764 hectares is one of the main irrigation-area in West Sumatra Province. The objective of the present study is to determine the performance index of the main irrigation network (main building, primary canal and secondary canal) of the Batang Anai I Irrigation-Area based on the Minister of Public Works and Public Housing Regulation No. 12/PRT/M/2015, and to determine the level of service of it based on the MASSCOTE method. The method based on Permen PU No.12/PRT/M/2015 examines six aspects. They are physical infrastructure, planting productivity, supporting facilities, personnel organization, documentation and farmer association (WUA). The MASSCOTE method is based on the Rapid Appracial Procedure (RAP) which has four indicators in its assessment, namely; indicators of service, farmer association, human resources and of channel-operation modernization. Based on the Minister Regulation, the Batang Anai I is in the moderate category (76.85%) in the physical performance. Meanwhile, based on the MASSCOTE method, it is in the good category (3.22 in 4-scale) in the level of service. Based on both those categories, the management of the irrigation area only needs the operation and maintenance action.
Detection of flood inundation in serayu watershed using landsat-8 and sentinel-2 satellite imagery
Authors: Suroso  , Zikri A , Santoso P B , Ardiansyah
Published: May 2023

Floods are natural disasters that occur routinely almost every year in various regions in Indonesia, especially on the island of Java. According to the National Disaster Management Authority (BNPB), in 2001-2021 there were 5542 floods in Java. Determining the area of flood inundation is very important to know the potential and risk of the impact of flooding in an area. The purpose of this study is to develop a method of detecting flood inundation areas based on Landsat-8 and Sentinel-2 satellite imagery data using the Normalized Difference Water Index (NDWI) parameter. The Maximum Likelihood Classification (MLC) method was chosen to classify inundated areas and non-flooded areas. The Landsat-8 and Sentinel-2 satellite images were selected during the wet months that usually rain, January, February, March, November and December in 2020. The results show that the Landsat-8 satellite can detect water inundation better than the Sentinel-2 satellite. The results are influenced by the difference in recording time between the two satellites, the presence of clouds that cover the research location, and Landsat-8 imagery data that does not cover the entire location area.
Backwater flow analysis due to the construction of the check dam series on Aie Dingin River using HEC-RAS
Authors: Daoed D , Sunaryo  , Arsyad F
Published: May 2023

River profiles with steep slopes and loose-grained soil types will easily be carried away by river currents. One way to reduce the sediment rate is by constructing a check dam or a series of check dams. However, the effect of a series of check dams can influence each other, due to backwater flow. On the one hand, it is advantageous because the flow velocity is reduced, but it will raise the water level downstream of the dam and increase the height of the embankments and ponds. Based on the foregoing, an analysis of the backwater flow was carried out using HEC-RAS. The results obtained are that water backflow occurs in two water structures, namely the Koto Tuo and Koto Pulai check dams. The backwater flow is quite long, almost reaching the previous check dam. Where the length of the backwater flow is only up to the final threshold and it is advisable to observe local sedimentation behavior due to backwater flow.
Effects of COVID-19 on transportation services and travel behaviour in Malaysia
Authors: Gungat L , Deh D R , Putri E E
Published: May 2023

Movement restrictions implementation due the COVID-19 pandemic affected people’s mobility and and transportation sectors globally. Tourism, retail, transportation, and hospitality also suffered significant consequences that indirectly impacted a country’s economic stability. Hence, this paper presents the Malaysian experience with the effects of the pandemic on transportation services and travel behaviour. Online sources, secondary data and a questionnaire survey were employed to collect the relevant data. These data were further analysed and presented in this paper. In general, transportation sectors involving air, rail and public bus showed decreased demand and services. A severe drop in services was observed in air transportation which is more than 97%. Most people prefer not to use public transportation to avoid the risk of COVID-19 infection. Noticeable changes in travel behaviour and mode preference during and pre-pandemic are observed, particularly on trips related to work/school. Key pandemic factors concerning transportation were fear of infection and social distance. Hence, most people prefer to use a private vehicle. The changes in transportation service and travel behaviour result in severe losses in the transportation sector in Malaysia.
Developing pedestrian evacuation path parameters based on the requirements of Indonesia National Agency of Disaster Management and the Indicators of the Global Walkability
Authors: Rifwan F , Yosritzal  , Purnawan  , Yossyafra
Published: May 2023

The tsunami incident in 2004, in Aceh, was killed around 230,000 people and destroyed more than 1,000 buildings. Many accidents also occurred related to the earthquakes and tsunamis in Indonesia. For example, when the big earthquakes happened in Padang City, people evacuated themselves by using cars or motorbikes (motorized movement). It created a problem; and became worse when the movement was not effective. All research related to evacuation movement suggested that walking is better than moving using vehicles. Thus, people who will evacuate by walking should be supported by good and sufficient infrastructure, such as the path. Up to recent time, there has been no research conducted in relation to finding the solution this problem. Therefore, this article reports on the research that focused on the parameters of the path design. The validity and reliability of the test, were measured by experts. The research respondents filled the form and their responses were taken as the data analyzed to get the parameters, indicators, and levels based on the adjustment of BNPB (National Agency of Disaster Management) and GWI (Global Walkability Indicators) guidelines. In conclusion, the four parameters: walking path mode conflict, availability of walking path, amenities, and obstruction were found.
Upstream Brantas Watershed management strategies for flood mitigation (a review: Batu District)
Authors: Handayani D A , Kurniadi A , Bahar F
Published: May 2023

The floods that occurred in Batu in November 2021 were the result of improper management of the upstream area of the Brantas river. This paper reviewing the parties involved in s watershed management strategies with floods. We start by reviewing the watershed management by the stakeholder in upperment areas Brantas. Then we discuss the mitigation strategies’ role in invoicing the negative impact of floods. This research uses qualitative descriptive methods through secondary data collection and literature studies on previous research on management strategies for the upstream area of the Brantas River. This result of the analysis showed that the watershed manages by several leading sectors. The good carrying capacity of the upstream area of the Brantas river is a collaboration of management by the stakeholders. That ability to generate the desired output of basic resources to reduce the risk of several flooding disasters, while maintaining the desired environmental quality. Efforts to develop the regional management can be pursued through community empowerment activities which in practice are carried out through various forms of cooperation/partnerships including community groups. That ability to generate the desired output of basic resources to reduce disaster risk of more severe flooding disasters, while maintaining the environmental quality.
The Importance of Village Resilience Assessment in Village Based Programs to Support Regional Resilience
Authors: Nurmala Virana Fatwa , Pelita Panjaitan Berton Suar , Subiyanto Adi
Published: May 2023

Village Resilience Assessment is a process of assessing resilience that is carried out by the community independently to determine the level of resilience. This assessment framework adopts village and urban village disaster resilience standards in SNI 8357:2017 and adapts the DROP (Disaster Resilience of Place) model. The methodology in this study uses a qualitative method with a descriptive analysis approach. Assessment of village disaster resilience produces several outputs, such as Village Resilience Index Values, Village Resilience Levels, and recommendations for action to increase village capacity. The Village Resilience Index value consists of three levels, namely Tangguh Utama <83.33, Tangguh Madya 58.3 – 83.33, and Tangguh Pratama <58.3. The results show that the Village resilience assessment is important because the Village Resilience Assessment is a tool to measure the level of village resilience in a simple way so that it will make it easier for village communities to carry out action plans to reduce vulnerability and increase capacity. disaster resilience village which aims to map the conditions and initial description of the level of risk, level of vulnerability and level of village capacity in dealing with disaster threats.
Numerical Modelling of Constructed Wetland using Software HYDRUS 2D
Authors: Adek Rizaldi M. , Limantara Lily Montarcih , Suhartanto Ery , Harisuseno Donny , Izzaty Nadia Karima
Published: May 2023

One of the problems involving water bodies is the pollution of water sources, which later becomes the parent of various social, economic, and health problems. One of these conditions can be overcome by utilizing phytoremediation through constructed wetlands. HYDRUS is a software that offers easy modelling of pollutant decay mechanisms in water bodies and constructed wetlands using finite element method. This study aims to show and analyse how HYDRUS software can model the mechanism in constructed wetland by using finite element method. The parameters observed are the time for the pollutant, namely ammonia, nitrate, and inorganic phosphorous, to reach the outlet, and the response curve of the pollutant loading on the model. From the simulation, it can be inferred that the maximum velocity of the water going through the constructed wetland is 8.11 m/day, or 811 cm/day. The dominating velocity in the wetland is around 160 cm/day, or 1.6 m/day. The response curve of the pollutant transport is also in accordance with theoretical response for impulse loading. The result yields the effectivity of simulated constructed wetland, which are 90.33% for ammonia and nitrate, and 90.26% for inorganic phosphorous. The result yields quite optimistic effectivity of the constructed wetland, which may be caused by the assumptions made in the model, which goes through simplification method. It can also be caused by the differences in plants assumption. In the HYDRUS simulation, the plant used is grass, which does not specify what kind of grass. Meanwhile, the physical simulation uses water bamboo.
Village resilience to tsunami hazard: a Desk Research on the west-coastal villages of the Regency of Serang, Province of Banten, Indonesia
Authors: Tiwi D A , Ganesha D , Akhirianto N A , Putra A P , Umbara R P , Shomim A F , Astisiasari
Published: May 2023

This desk research delivers an introductory study of village resilience on the western coastline of the Regency of Serang, Province of Banten, Indonesia. It aims to preliminary characterize the level of village resilience to a tsunami hazard. This study utilizes secondary dataset, retrieved from the authorized institutions (statistical bureau and regional government) and accredited news (government bulletin and news agency). It adopts and modifies the four notable methods on resilience analysis, in order to accommodate the relevancy to study area’s dataset availability. The reformulated method is developed by taking into account the variables of: vulnerability (physical, social, and economical aspects) and capacity (preparedness and mitigation measures) within a village as its unit analysis. Furthermore, SWOT analysis is conducted to present the appropriate recommendations for strengthening the resilience. The study finds that generally, tsunami resilience in study area is still considered inadequate, where among the eleven villages, seven villages set low for the Resilience Index (RI). In regards to this, SWOT analysis assembles a total of fifteen possible strategies and seventeen desk-based recommendations to promote the tsunami-resilient village.
Community-based disaster risk reduction efforts in facing the threat of abrasion disasters at Bungin Beach, Bekasi Regency during the covid-19 pandemic
Authors: Fathoni S , Sutisna S , Supriyatno M
Published: May 2023

Abrasion causes coastal areas to have a very high level of dynamics and often has an impact on environmental damage, so it needs to be anticipated. In the last 2 years, the whole world has faced a crisis caused by the pandemic due to Corona Virus Disease (Covid-19). During the pandemic, the environment where coastal communities live is still threatened with abrasion. Some mangrove planting and rehabilitation activities had to be stopped to suppress the spread of the virus. The purpose of this study was to identify the role of community groups (Tourism Awareness Group) as a key factor in overcoming abrasion events during the Covid-19 pandemic at Bungin Beach. Interviews and direct observations were conducted to obtain survey data. Additional analyzes were then carried out through relevant journals and literature reviews. As a result, from 1997 to 2021 there has been abrasion on Bungin beach. The Tourism Awareness Group plays a role in post-pandemic recovery, especially in the economic sector. Through mangrove planting activities, not only to restore the economy of coastal communities during the pandemic but also to protect coastal ecosystems from the threat of abrasion on Bungin Beach.
Underground-caves connectedness preview using the geoelectrical profiling method as an effort to revive natural tourism in “Gua Pandan,” East Lampung Regency
Authors: Antosia R M , Akbar H H , Santoso N A , Putri I A , Farishi B A , Natalia H C
Published: May 2023

The Covid-19 pandemic has made one of the tourists in the East Lampung regency inactive, namely “Gua Pandan.” Due to its unique location geologically, efforts must be made to revive the area. One of the approaches is applying an indirect method, namely the geophysical method. One of them is the geoelectrical profiling method. Six lines are spread in the study area with a length of 70-105 m. The target is a cave filled with air because it is suitable as a tourist spot. Based on the measurement results, a very high resistivity value of more than 5,000 Ωm is suspected to be an air-filled cave. The cave area that is probably safe is about 120 m long with 1-3 m depth below the ground surface, 2-8 m width, and 2-6 m height. However, a safety assessment is necessary for feasibility so that the cave is worthy of being re-activated as a tourist spot.
Junior high school students preparedness toward earthquake in urban and rural areas in Pesisir Selatan
Authors: Salsabila R , Alfian A R , Rahman A
Published: May 2023

The earthquake on September 30th, 2009, damaged 35 schools in Pesisir Selatan, so student preparedness really needs to be improved to reduce fatalities and the impact of earthquake. This study aims to determine preparedness differences of junior high school students in urban and rural areas against earthquake in Pesisir. This study is quantitative with a cross-sectional design. The research was conducted in junior high school located in urban and rural areas in Pesisir Selatan in July-August 2021 with 84 students selected using the proportional systematic random sampling technique. Data collection was done through interview with questionnaire. The parameter employed was LIPI’s which consists of multiple facets such as knowledge, emergency response, early warning, and resource mobilization. Data were then analyzed using the Mann-Whitney test with α= 0.05 and CI = 95%. The results showed there were differences preparedness of junior high school students in urban and rural areas with p-value = 0.000. Therefore, the Government through the Health Office and Education Office, and regional disaster management agency can cooperate regularly and periodically regarding the provision of simulations/training and monitoring regarding disasters to students.
Vulnerability Assessment of non-engineered houses related to earthquake in West Pasaman District
Authors: Zakir Rahmat Fadli , Hakam Abdul , Istijono Bambang , Noer Melinda , Rahmadilla Hape Syafira
Published: May 2023

The earthquake on February 25, 2022, in West Pasaman resulted in damage to people’s houses as well as fatalities. The quake happened just under the Mount of Talamau, 18 km northeast of the city of Simpang Empat City, with a magnitude of 5.2 M. This earthquake was followed by small earthquakes that occurred until February 27, 2022. Damage to houses in the earthquake-affected area became the focus of attention in this research to assess the housing vulnerability related to the earthquake hazard. The vulnerability assessment of house buildings is critical in earthquake-prone areas because it can provide information about the impacts on the buildings. The vulnerability of house buildings is closely related to the potential for damage due to earthquake hazards. The benefit of the vulnerability assessment of house buildings is to arrange the mitigation action plan to reduce the level of damage to building structures. The method, in turn, can reduce the number of fatalities as well. Buildings with a high level of vulnerability to earthquakes are non-engineered or residential buildings that are built without considering essential factors in planning, such as the necessary technical requirements.
Broadband structured light using digital micro-mirror devices (DMDs): a tutorial
Authors: Perumal Leerin , Forbes Andrew
Published: May 2023

Laser beam shaping is a venerable topic that enjoyed an explosion in activity in the late 1990s with the advent of diffractive optics for arbitrary control of coherent fields. Today, the topic is experiencing a resurgence, fuelled in part by the emerging power of tailoring light in all its degrees of freedom, so-called structured light, and in part by the versatility of modern day implementation tools. One such example is that of digital micro-mirror devices (DMDs), for fast, cheap and dynamic laser beam shaping. In this tutorial we outline the basic theory related to shaping light with DMDs, give a practical guide on how to get started, and demonstrate the power of the approach with several case studies, from monochromatic to broadband light.
Hydrodynamic and transport behavior of solid nanoparticles simulated with dissipative particle dynamics
Authors: Haugen Jeffery , Ziebarth Jesse , Eckstein Eugene C , Laradji Mohamed , Wang Yongmei
Published: May 2023

Inertial migration of micro- and nanoparticles flowing through microchannels is commonly used for particle separation, sorting, and focusing on many lab-on-a-chip devices. Computer simulations of inertial migration of nanoparticles by mesoscale simulation methods, such as Dissipative Particle Dynamics (DPD) would be helpful to future experimental development of these lab-on-a-chip devices. However, the conventional DPD approach has a low Schmidt number and its ability to model inertial migration is questioned. In this work, we examine the ability of DPD simulations to investigate the inertial migration of rigid nanoparticles flowing through a slit channel. By varying the exponent and cutoff distance in the weight function of the random and dissipative forces, DPD models with Schmidt number varying between 1 and 370 were examined. We show that solvent penetration into nanoparticles and solvent-induced attraction between nanoparticles can be controlled by choosing appropriate interaction coefficients of the DPD conservative force and that these properties are not influenced by the Schmidt number of the DPD model. On the other hand, hydrodynamic properties and transport behaviour of rigid nanoparticles are influenced by the Schmidt number. With the conventional DPD model, nanoparticles tend to be evenly distributed across the channel and do not remain in steady-state positions during flow. At high Schmidt numbers, the particles migrate to long-lasting steady-state positions located between the channel center and walls, in agreement with known experimental observations. We conclude that to properly simulate inertial migration, modifications to the conventional DPD model that yield a high Schmidt number are required.
The effect of pulse voltage rise rate on the polypropylene surface hydrophilic modification by ns pulsed nitrogen DBD
Authors: LIU Feng , LI Shuhao , ZHAO Yulei , AKRAM Shakeel , ZHANG Li , FANG Zhi
Published: May 2023

The nanosecond (ns) pulsed nitrogen dielectric barrier discharge (DBD) is employed to enhance the hydrophilicity of polypropylene (PP) surface and improve its application effect. The discharge characteristics of the ns pulsed nitrogen DBD with different pulse rise times (from 50 to 500 ns) are investigated by electrical and optical diagnostic methods and the discharge uniformity is quantitatively analyzed by image processing method. To characterize the surface hydrophilicity, the water contact angle (WCA) is measured, and the physical morphology and chemical composition of PP before and after modification are analyzed to explore the effect of plasma on PP surface. It is found that with increasing pulse rise time from 50 to 500 ns, DBD uniformity becomes worse, energy efficiency decreases from 20% to 10.8%, and electron density decrease from 6.6 × 1011 to 5.5 × 1011 cm−3. The tendency of electron temperature is characterized with the intensity ratio of N2/N+
2 emission spectrum, which decreases from 17.4 to 15.9 indicating the decreasing of T
e with increasing pulse rise time from 50 to 500 ns. The PP surface treated with 50 ns pulse rise time DBD has a lower WCA (∼47°), while the WCA of PP treated with 100 to 500 ns pulse rise time DBD expands gradually (∼50°‒57°). According to the study of the fixed-point WCA values, the DBD-treated PP surface has superior uniformity under 50 ns pulse rise time (3° variation) than under 300 ns pulse rise time (8° variation). After DBD treatment, the increased surface roughness from 2.0 to 9.8 nm and hydrophilic oxygen-containing groups on the surface, i.e. hydroxyl (−OH) and carbonyl (C=O) have played the significant role to improve the sample’s surface hydrophilicity. The short pulse voltage rise time enhances the reduced electric field strength (E/n) in the discharge space and improves the discharge uniformity, which makes relatively sufficient physical and chemical reactions have taken place on the PP surface, resulting in better treatment uniformity.
Etching characteristics and surface modification of InGaSnO thin films under Cl2/Ar plasma
Authors: JOO Young-Hee , CHOI Jae-Won , HOU Bo , KWON Hyuck-In , UM Doo-Seung , KIM Chang-Il
Published: May 2023

Indium gallium tin oxide (IGTO) thin films have the potential for high mobility and low-temperature processing, which makes them suitable for applications such as display backplanes and high-voltage switching devices. However, very few studies have investigated the plasma-etching characteristics of IGTO and changes in its properties after etching. In this study, the etching characteristics of IGTO were investigated using Cl2/Ar plasma, and changes in surface properties were analyzed. Results showed that the etch rate increased with an increase in the proportion of Cl2, with the highest etch rate observed at 69 nm min−1 in pure Cl2 plasma with a gas flow rate of 100 sccm. Furthermore, increased radio-frequency power caused a rise in the etch rate, while a process pressure of 15 mTorr was optimal. The primary etching mechanism for IGTO thin films under Cl2 plasma was a chemical reaction, and an increased work function indicated the occurrence of defects on the surface. In addition, the etching process reduced the surface roughness of Cl2-containing plasma, whereas the etching process in pure Ar plasma increased surface roughness. This study contributes to a better understanding of the plasma-etching characteristics of IGTO and changes in its properties after etching, providing valuable insights for IGTO-based applications.
Reliable p-type organic permeable base transistors—the missing component for integrated circuits
Authors: Wang Juan , Bonil Amric , Vahland Jörn , Kleemann Hans
Published: May 2023

Due to their nm-range channel length, vertical organic transistors are gaining scientific interest to overcome the frequency limitations of lateral organic transistor. Especially, vertical organic permeable base transistors (OPBTs) with a structure resembling a vacuum-tube-triode stand out due to their excellent electrical performance. Recently, n-type OPBTs have been demonstrated with excellent performance and great potential to be applied in high-frequency logic circuits, display driving circuits, and light-emitting devices. However, achieving adequate p-type OPBTs to catch up with the performance of n-type devices is still challenging. Here, we report on the peculiar finding that the extended exposure of p-type OPBTs to ambient air during the fabrication has a positive effect on the electrical performance and tremendously improves the yield of devices to

100
%

. Upon exposing the fresh device to air, oxygen diffuses into the semiconductor layer interacting with the base electrode, which facilitates the formation of pinholes in the base and creates an insulator layer around the base. Moreover, as oxygen acts as a p-dopants to the p-type semiconductors used in this work, the device performance is further improved, manifesting in an increased on-state current. However, as the exposure time increases, different p-type organic semiconductors show different behavior depending on their ionization potential. Comparing two semiconductor materials with a difference in their ionization potential of 0.4 eV, we show that long-term degradation could be effectively suppressed. Therefore, the positive effect of air exposure could be utilized to optimize p-type OPBTs, which offers a simple and universal way to construct high performance p-type OPBTs and possibly also complementary circuits.
The Meaning of Online Social Work Education for Students and Faculty during COVID-19: Between Preservation and Change
Authors: Paz Yaara , Koren Chaya , Shklarski Liat , Latzer Yael
Published: May 2023

Academic online social work (SW) education has developed over the decades, fully transitioning to it following the COVID-19 pandemic. Studies have examined the emotional responses, coping strategies and resilience of faculty and students to this transition. Our aim is to examine online education experiences and their meaning for faculty and SW students following the COVID-19 pandemic. Semi-structured qualitative interviews were audio-recorded, transcribed verbatim and analysed based on principles of thematic analysis. Interviewees included fifteen SW students and fifteen faculty members at schools of SW (n = 30) from universities and colleges throughout Israel, who also participated in a quantitative survey addressing online SW education. Findings include two themes: (i) Between the illusion of intimacy and the illusion of anonymity: Is it so? (ii) Experiences of difficulty, acceptance and choice relating to online education interactions. Both themes refer to interpersonal dimensions of communication and contact between faculty and students and among students. The desire to preserve a traditional education format versus openness to the online platform is discussed using critical reflexivity. Alternative education programmes combining the two should be developed. The unique and deceptive interplay between intimacy and anonymity in the online space should be considered in courses relying on interpersonal interaction and self-disclosure.
Magnetoencephalogram-based brain–computer interface for hand-gesture decoding using deep learning
Authors: Bu Yifeng , Harrington Deborah L , Lee Roland R , Shen Qian , Angeles-Quinto Annemarie , Ji Zhengwei , Hansen Hayden , Hernandez-Lucas Jaqueline , Baumgartner Jared , Song Tao , Nichols Sharon , Baker Dewleen , Rao Ramesh , Lerman Imanuel , Lin Tuo , Tu Xin Ming , Huang Mingxiong
Published: May 2023

Advancements in deep learning algorithms over the past decade have led to extensive developments in brain–computer interfaces (BCI). A promising imaging modality for BCI is magnetoencephalography (MEG), which is a non-invasive functional imaging technique. The present study developed a MEG sensor-based BCI neural network to decode Rock-Paper-scissors gestures (MEG-RPSnet). Unique preprocessing pipelines in tandem with convolutional neural network deep-learning models accurately classified gestures. On a single-trial basis, we found an average of 85.56% classification accuracy in 12 subjects. Our MEG-RPSnet model outperformed two state-of-the-art neural network architectures for electroencephalogram-based BCI as well as a traditional machine learning method, and demonstrated equivalent and/or better performance than machine learning methods that have employed invasive, electrocorticography-based BCI using the same task. In addition, MEG-RPSnet classification performance using an intra-subject approach outperformed a model that used a cross-subject approach. Remarkably, we also found that when using only central-parietal-occipital regional sensors or occipitotemporal regional sensors, the deep learning model achieved classification performances that were similar to the whole-brain sensor model. The MEG-RSPnet model also distinguished neuronal features of individual hand gestures with very good accuracy. Altogether, these results show that noninvasive MEG-based BCI applications hold promise for future BCI developments in hand-gesture decoding.