bluuebunny/crossref_metadata_2025 huggingface dataset:
Tail-stiffness optimization for a flexible robotic fish
Authors: Zou Qianqian , Zhou Chao , Lu Ben , Liao Xiaocun , Zhang Zhuoliang
Published: July 2022

Undulation regulation in a robotic fish propelled by a passive flexible tail is more similar to that of a natural fish than with a rigid tail, owing to the smooth curvature of the flexible tail. Moreover, it has been observed that fish change the stiffness of their bodies to adapt to various swimming states. Inspired by this, a stiffness optimization scheme is explored for a novel elastic tail, which can improve the performance of the robotic fish. Spring steels are used as passive flexible joints of the fishtail; these can be easily expanded into multi-joint structures and the joint stiffness can be altered by changing the joint size. In this study, the Lagrangian dynamic method is employed to establish a dynamic model of the robotic fish in which passive flexible joints are simplified by a pseudo-rigid-body model. In addition, the hydrodynamics of the head and tail are analyzed using the simplified Morison equation and quasi-steady wing theory, respectively. Furthermore, to determine unknown hydrodynamic parameters in the dynamic model, a parameter identification method is applied. The results show that the identified simulation speeds fit the experimental speeds well within a wide range of stiffness values. Finally, to improve performance, the influence of joint stiffness and frequency on swimming speed is investigated based on the identified dynamic model. At each frequency, the optimal joint stiffness distribution is one that reduces the stiffness from the front to the rear. At the maximum driving frequency of 2.5 Hz, the optimal swimming speed is 0.3 body lengths per second, higher than that when rigid joints are used.
Hydrodynamic interaction of dorsal fin and caudal fin in swimming tuna
Authors: Zhang Jun-Duo , Sung Hyung Jin , Huang Wei-Xi
Published: July 2022

Tuna, which are known for high-performance swimming, possess a large crescent dorsal fin (DF) and a caudal fin (CF) that differ from those of other fishes. The hydrodynamic interaction between the DF and CF in tuna, which are represented by two tandem 3D flapping plates, is numerically explored in the present study. Hydrodynamic properties and wake structures of the models with and without a DF are compared to investigate the effects of the DF. The thrust on the CF is substantially enhanced by the DF, whereas the force on the DF is not affected by the CF. The constructive interaction between the leading-edge vortex (LEV) on the CF and the vortices shed from the dorsal fin (DFVs) is identified from 3D wake topology and 2D vorticity distributions. The circulation of spanwise vorticity quantitatively reveals that the LEV on the CF is strengthened by the same-signed DFV. The effect of the flapping phase of the CF is examined. The DF–CF interaction is sensitive to the flapping phase at a short spacing, whereas a long spacing between the two fins enables a robust constructive interaction in tuna swimming. A systematic study is carried out to explore the effects of the Strouhal number (St) and the Reynolds number (Re) on the interaction of the fins. The enhancement of thrust due to the DF is diminished at St = 0.63, whereas the Re does not substantially influence the constructive DF–CF interaction.
Aligning citizen science and remote sensing phenology observations to characterize climate change impact on vegetation
Authors: Domingo-Marimon Cristina , Masó Joan , Prat Ester , Zabala Alaitz , Serral Ivette , Batalla Meritxell , Ninyerola Miquel , Cristóbal Jordi
Published: July 2022

Phenology observations are essential indicators to characterize the local effects of climate change. Citizen participation in the collection of phenological observations is a potential approach to provide data at both high temporal scale and fine grain resolution. Traditional observation practices of citizen science (CS), although precise at the species scale, are limited to few observations often closely located to an observer’s residence. These limitations hinder coverage of the great variability of vegetation phenology across biomes and improvement of the knowledge of vegetation changes due to climate change impacts. This study presents a new approach to overcome these limitations by improving CS guidance and feedback as well as expanding phenology report sites and observations across different habitats and periods to contribute to monitoring climate change. This approach includes: (a) a new methodology focused on harmonizing remote sensing phenology products with traditional CS phenology observations to direct volunteers to active phenology regions and, (b) a new protocol for citizen scientists providing tools to guide them to specific regions to identify, collect and share species phenological observations and their phenophases. This approach was successfully tested, implemented and evaluated in Catalonia with more than 5000 new phenologically interesting regions identified and more than 200 observations collected and Sentinel-2 derived phenometrics were demonstrated as of good quality.
Urbanization altered atmospheric humidity diurnally and seasonally through ecohydrological processes in five urban agglomerations in China
Authors: Huang Xiaolin , Jin Kailun , Chen Dongxu , Zheng Qingzhou , Hao Lu
Published: July 2022

The large-scale conversion of vegetated land to urban use leads to a significant reduction in evapotranspiration (ET) due to the lack of vegetation, which may aggravate urban dry island (UDI) effect. Analysis of diurnal and seasonal (e.g. growing season) variations in UDI can help us to better identify the role of ET in processes of UDI. We compared six-hourly weather observation data (1980–2017) from 140 paired urban-rural stations across a large climatic gradient in China to explore how near-surface atmospheric dryness changed both diurnally and seasonally, and its relationship with urbanization-associated ecohydrological processes. We showed that the difference in atmospheric dryness (i.e. UDI intensity) between urban and rural areas, as measured by specific humidity (Δq < 0), is more pronounced during the daytime and growing seasons. The nighttime urban wet island (UWI, Δq > 0) effect partially offset daily UDI effect, which has made the latter underestimated. Intensified nighttime urban heat island (UHI) reduced the diurnal temperature range (DTR) in cities and thus enhanced nighttime UWI effect from 2000 to 2010. However, after 2010, nighttime UWI effect weakened or disappeared, whereas nighttime UDI intensified in humid cities, resulting in a significant increase in daily UDI. Intensified UHI and UDI are often closely coupled (synchronous occurrence) through latent heat (LE) or ET processes, especially after 2010. Our results indicate that the conversion of vegetated lands to urban impervious surface, especially in humid regions, leads to the reduction in transportation during daytime and evaporation at night in urban cores, which alters the relationships between near-surface air temperature, atmospheric moisture, and ET. The present diurnal and seasonal variations in UDI were delineated in detail to explicate the patterns and interconnections of local urban climate and surface ecohydrological processes, which are critical for ecosystem services in urban landscape design.
Smectic layering: Landau theory for a complex-tensor order parameter
Authors: Paget Jack , Alberti Una , Mazza Marco G , Archer Andrew J , Shendruk Tyler N
Published: July 2022

Composed of microscopic layers that stack along one direction while maintaining fluid-like positional disorder within layers, smectics are excellent systems for exploring topology, defects and geometric memory in complex confining geometries. However, the coexistence of crystalline-like characteristics in one direction and fluid-like disorder within layers makes lamellar liquid crystals notoriously difficult to model—especially in the presence of defects and large distortions. Nematic properties of smectics can be comprehensively described by the

Q

̲

̲

-tensor; however, lamellar order can exist independent of nematic alignment. To capture the features of the smectic layering alone, we develop a phenomenological Landau theory for a complex-tensor order parameter

E

̲

̲

, which is capable of describing the local degree of lamellar ordering, layer displacement, and orientation of the layers. This theory accounts for both parallel and perpendicular elastic contributions. In addition to resolving the potential ambiguities inherent to complex scalar order parameter models, this model reduces to previously employed models of simple smectics, and opens new possibilities for numerical studies on smectics possessing many defects, within complex geometries and under extreme confinement.
The 5th Indonesian Society of Limnology (MLI) Congress and International Conference 2021
Authors: Setiawan F , Toruan R L , Subehi L , Rahmat A
Published: July 2022

The 5th Indonesian Society of Limnology (MLI) Congress and International Conference 2021 is a biannual conference organized by the Indonesian Society of Limnology, with the theme is “Building synergies towards sustainable use of inland waters.” This year due to the COVID-19 pandemic, we hold the event virtually from 2nd to 3rd December. The objectives of this event are to (1) Connect, discuss, share and create a mutual network among communities from different backgrounds who are interested in inland waters ecosystem; (2) Disseminate science & technology and lessen the gap between scientific and common communities through fruitful discussion settings; (3) Underpin sustainable use and management of inland aquatic ecosystems.

There were four keynotes speakers, four invited speakers, and 66 general presenters in the conference sessions. In total, 116 participants were registered and joined the conference. The first keynote speaker was Prof. Dr. Gadis Sri Haryani from the Research Center for Limnology and Water Resources, National Research and Innovation Agency of the Republic of Indonesia (BRIN), Indonesia, who presented research about Migratory freshwater fish in Indonesia: Threats and conservation efforts. The second presenter was Dr. Robert Walsh from the Australian Water Life, Australia, who presented research about Discover the world of Micro-invertebrates. The third keynote speaker was Dr. Khamla Inkhavilay from the National University of Laos, Lao PDR, who presented Persistent Organic Pollutants in Wetland of Mekong Basin. The fourth speaker was Dr. Kwanraree Joy Sirikanchana from the Chulabhorn Research Institute, Thailand, who presented Microbial Source Tracking and Quantitative Microbial Risk Assessment for Sustainable Water Pollution Management.

In addition, the four invited speakers and 66 general presenters split into four rooms for parallel discussions which covered the latest research on inland water ecosystems, including; (1) Biotic resources, biodiversity, and conservation; (2) System Dynamic of inland waters; (3) Applied technology for the management and pollution control; (4) Modelling, system information, decision support tool, disaster risk reduction; (5) Management, policies, regulation, education, social, economy, and culture.

We highly appreciate the generous support from Research Centre for Limnology-BRIN (Indonesia), Australian Water Life (Australia), Chulabhorn Research Institute (Thailand), National University of Laos (Lao PDR), Southeast Asian Limnological Network (SEALnet), Advisory Board, Steering and Organizing committee and all presenters and participants.

List of Committees, Advisory Board, Steering Committee, Scientific Committee, Organizing Committee, Documentation, all photos are available in this pdf.
Migratory freshwater fish in Indonesia: Threats and conservation efforts
Authors: Haryani GS
Published: July 2022

The process of fish migration is one of the most important biological aspects of the life of certain fish species, including fish species that live in freshwaters. In Indonesia’s freshwaters, several types of fish migrate to fulfill parts of their life cycle, such as Anguilla spp., Tor spp., and Rasbora spp., which have economic and ecological values. Fish habitats and migration routes can be affected by many cause changes, including dam constructions, other infrastructure constructions, drainage of wetlands, and floodplain disconnection. Other threats to migratory freshwater fish are overfishing and pollution. In Indonesia, most migratory freshwater fish threats were obstructions to free-flowing rivers, such as dams, and the exploitation of adult fish that migrate for spawning. Some management approaches should conserve and sustain the use of migratory freshwater fish.
Condition of physical and chemical parameters of tropical eel genus Anguilla habitat in Citarik and Cicatih rivers in the Cimandiri watershed, Sukabumi, West Java
Authors: Wildan D M , Rahmadya A , Ridwansyah I , Daruati D , Triyanto  , Dewi A P , Fachri F R
Published: July 2022

Land changes around the Citarik and Citatih rivers will affect the water quality. These changes will affect eels’ life (Anguilla spp.) as fish that live in the area. This study aimed to determine water quality (physical and chemical) and the presence of eels (Anguilla spp.) in the Citarik and Citatih rivers in the Cimandiri watershed Sukabumi, West Java. This research was conducted from April to May 2021. Data collection was carried out in the upstream, middle, and downstream areas of the Citarik and Cicatih rivers. The results of this study show that the Ciratik river has a turbidity of 53.3-93.6 NTU, current 0.448-0.478 m/s, temperature 25.55-26.65 °C, TDS 0.002 0.041 mg/l. Eels caught amounted to 13 individuals of (Anguilla Marmorata); Cicatih river had a turbidity 84.4-264 NTU, current 0.142-0.814 m/s, temperature 26.76-29.05 °C, TDS 0.079-0.096 mg/l, and eels caught amounted to 12 individuals of (Anguilla Marmorata). Based on the results, environmental changes in the Citarik and Citatih rivers are still normal, as evidenced by the water quality that is still following the needs of the eels and the presence of eels.
Functional Groups of Phytoplankton and Their Relationship with Environmental Factors in Lake Maninjau, West Sumatra, Indonesia
Authors: Sulastri  , Nomosatryo S , Henny C , Sulawesty F
Published: July 2022

Lake Maninjau is a eutrophic lake indicated by the frequent occurrence of cyanobacterial blooms. The phytoplankton functional groups (FGs) reflect the environmental characteristics and can be useful to monitor the trophic state and evaluate lake’s environmental conditions. This study aims to perceive the composition of phytoplankton FGs and their relation to the environmental factors in Lake Maninjau. The data including phytoplankton and environmental factors were collected in 2001, 2005, 2009, 2014, 2015, 2016, and 2018. There were 21 FGs of phytoplankton recorded in Lake Maninjau. FGs of D, J, F, and NA were commonly found in this Lake. The phytoplankton FGs reflected the dynamic of the environmental characteristics of the lake. The FGs NA representative of oligo to mesotrophic habitat type were predominated accounting for 66.3% to 67.69 % in May 2005 with the lake’s conditions characterized by low TP concentration, high Secchi depth and TN: TP ratio. The FGs of M representative of eutrophic to hypereutrophic habitat type were predominated accounting for 74.14 % to 94.96 % in April 2018 with the lake’s conditions characterized by high TP concentration, low TN: TP ratio, and Secchi depth. A canonical correspondence analysis (CCA) showed that temperature, conductivity, and total phosphorus are important environmental factors to have influenced the succession of phytoplankton FGs in Lake Maninjau.
Zooplankter - water fleas Daphnia magna - respond to phosphorus enrichment in pond water
Authors: Tanjung L R , Chrismadha T , Sulawesty F , Nafisyah E
Published: July 2022

Phosphorus has been pointed out as one of the limiting factors that limit freshwater bio productivity, so controlling this element at an optimum level is crucial to enhance pond water bio productivity. This study evaluates the impact of phosphorus enrichment in the pond (small lake) water on the zooplankton population development. The clear pond water of Situ Cibuntu, located in Cibinong – West Java, was fertilized up to the level of eutrophic water of Limboto Lake, in Gorontalo Province, by addition of adequate level of phosphorus in aquaria placed in a greenhouse. The phytoplankton, as well as the zooplankton, was monitored twice a week for two weeks. Phytoplankton development was represented by the chlorophyll content in the water, while the water flea Daphnia magna was introduced to observe water carrying capacity in supporting zooplankton life. The result shows that the growth rate of total phytoplankton significantly increased in response to phosphorus enrichment, indicating phosphorus limitation, followed by the development of the daphnid population. The chlorophyll-a reached the maximum concentration of 15.22 mg/m3 on day-7 of the experiment, while the maximum daphnid population of 1,272 individuals was enhanced on day-10. This experiment emphasized the importance of phosphorus control in managing lake water bio productivity.
Benthic Macroinvertebrates of Five Small Lakes in Ciliwung Watershed and Estuary, Indonesia
Authors: Imroatushshoolikhah  , Dina R , Sari L , Aisyah S , Sudarso J , Wahyudewantoro G , Muit N
Published: July 2022

Small lakes are biodiversity hotspots of freshwater ecosystems, home for fauna including benthic macroinvertebrates fauna which play vital roles as it supports food sources for higher-level organisms such as fishes. This research aims to investigate the composition of benthic macroinvertebrates community in some small lakes located in the Ciliwung watershed that surrounds Bogor, Depok, and Jakarta. Samples were undertaken on April and June 2021 from four small lakes located at the Ciliwung watershed. They are Telaga Warna, Situ Cikaret, Cincin urban lake, and Sunter urban lake. Also includes an estuary urban lake ecosystem, Angke lake. A total of 22 taxa were found, which consist of Mollusks (55.44%), Insects (6.27%), and Annelids (38.29%). Mollusk was composed of six families of Gastropods and one family of Bivalves. Meanwhile, the family of Diptera was the only Insect group. The abundance ranges between 101-4471 Ind/m2. The pattern shows that Gastropods were the predominant group in the downstream area meanwhile Annelids were the most abundant groups in the upstream, middle, and estuary areas.
Freshwater Fish and Fishery Activities in Koto Panjang Reservoir, Riau
Authors: Muthmainnah D , Rais A H , Fatah K , Makri M
Published: July 2022

Koto Panjang Reservoir is an artificial lake that, besides being utilized for electricity power or irrigation, is also utilized by the fishery sector. This paper describes the fish diversity, fishery activities, and potential yield of Koto Panjang Reservoir in Riau Province. Eight enumerators collected the primary data to record the total weight (kg) of catches and the number of fishing gear (unit) usage. The secondary data was obtained by literature search and relevant study results from related agencies. The potential fish yield of the reservoir was estimated by using the Morpho-Edaphic Index (MEI) model. The results showed that 29 species inhabited in Koto Panjang Reservoir with the potential fish production of about 222.32 kg/ha/year. Policy implementation can be implemented by restricting fisher and fishing gears numbers.
Brief overview of allochtonous phosphorus load on cascade reservoirs in Citarum River Basin, West Java Indonesia
Authors: Lukman L , Kartamihardja ES , Hariyadi S , Sunardi  , Sumiarsa D
Published: July 2022

The Citarum River, Indonesia, has undergone degradation due to the pollutants, including phosphorus, that enters the river and the reservoirs of Saguling, Cirata, and Juanda (The official name of Jatiluhur Reservoir). The observations of total phosphorus (TP) load instantaneously had been carried out on the three reservoirs and TP measurements from 8 to 12 August 2019. The TP concentration in the inlets was generally very high (> 0.3 mg L-1), whereas the average TP concentration in Saguling, Cirata, and Juanda Reservoirs was 0.378 mg L-1, 0.343 mg L-1, and 0.324 mg L-1, respectively. Based on the trophic criteria, the condition of the waters in the three reservoirs was hypertrophic. Meanwhile, the average TP level in the Saguling showed the highest level compared to other reservoirs, which is in line with the TP concentration that enters the Saguling Reservoir, which is generally very high. Based on the instantaneous inputs, the loading TP to Saguling, Cirata, and Juanda Reservoirs were 26.471 g sec-1, 36.241 g sec-1, and 55.573 g sec-1, respectively. This indicates that the loading of phosphorus from upstream to downstream tends to increase.
Plastic Debris in Citarum River
Authors: Hariyadi S , Taryono  , Wulandari D Y , Zulmi R , Permatasari P A , Amalo L F , Nur I A , Trissanti V N , Hurley R , Braaten H F V , Olsen M
Published: July 2022

Plastic pollution in an aquatic ecosystem may negatively impact ecology, aquatic species, and causes economic damage. Rivers provide an excellent opportunity for intercepting plastic pollution before it reaches the ocean. The aim of this study is to identify and quantify the number of plastic debris in the Citarum River. Plastic debris was collected from April to August 2021 at three sampling sites based on the stream location, i.e. upstream, midstream, downstream, using a framed pocket net with 1cm-mesh size as a sampler with the dimension of 2x1x3 meter that was installed at two transversal locations of the river. Observation was conducted three times a day, morning, noon, and afternoon each with 15-30 minutes duration. The methods applied include plastic debris separation, enumeration, classification, volume estimation, and weighting. Type of plastics that are commonly found in high number of items are plastic bags, clear plastic bags, and plastic packaging. The highest volume of plastic debris was found in the upstream part of the Citarum River compared to midstream and downstream. The existing reservoirs act as a trap for plastic debris and all riverine debris of the Citarum River. The plastic debris tends to be higher in the morning than noon or afternoon.
Macroplastic abundance at Lake Singkarak riparian, West Sumatera
Authors: Rohaningsih D , Henny C , Suryono T , Santoso A B
Published: July 2022

Macroplastic waste has been spotted around the shoreline and the waters of Lake Singarak, West Sumatra. Macroplastic waste has been the main source of microplastic pollution in the marine and freshwater environment. This study aimed to determine the types and abundance of macroplastic waste in the riparian area of Lake Singkarak. Macropalstic waste collection was carried out using a 0.25 m2 square transect with a radius of 10 m at six sampling locations around the lake. The collected macroplastic waste was then sorted by its type and calculated to determine the abundance of each type. The six collection points, the most abundant macroplastic waste was at a hotel area (Sumpur) with a waste weight of 3.07 kg/m2, while the shoreline area (Batu Baraguang) with less human activity was the location with the lowest waste abundance of 0.53 kg/m2. The dominating types of macroplastic waste at Sumpur Hotel were plastic film (33%) and hard plastic-fragment (19%). Not only at Sumpur Hotel, the plastic film type also became the most dominant type of macroplastic waste observed in all sampling locations, except at the main river inlet area (Sumani) where the most dominant type found was styrofoam. Overall, there were four types of macroplastic waste that dominated in the riparian of Lake Singkarak, namely plastic film, food bag packaging, hard plastic fragments, also bottle and cup packaging. A high abundance of macropalstic waste in the riparian area could pose a risk of microplastic pollution in Lake Singkarak.
Evaluation of Heliconia psittacorum in a Horizontal Flow Constructed Wetland (HFCW) System for the Treatment of Textile Wastewater
Authors: Henny C , Rohaningsih D , Susanti E , Sumi F , Waluyo A
Published: July 2022

Constructed wetlands have promised sustainable treatment systems to remediate various industrial wastewaters, including textile. Textile wastewater contains a complex constituent of inorganic and organic pollutants such as dyes, toxic metals, surfactants, nutrients, and total dissolved solids. This preliminary study aims to evaluate the performance of Heliconia psittacorum in a horizontal subsurface flow constructed wetland (HFCW) system for the remediation of textile wastewater. An HFCW system was set in a tank with a volume of 2 m3 divided by three sections where each section filled with coarse gravel, fine gravel, and sand media respectively resulted in a bed volume of 0.322 m3. The top of media was added compost then planted with Heliconia psittacorum. Diluted textile wastewater with a concentration of 20% was fed to the system in a continuous horizontal flow with an HRT of 2.7 days. The performance of the HFCW system showed water quality improvement from the wastewater within 11 weeks of observation. DO increased from < 2 to around 4 mg/L, pH and conductivity increased considerably. High decrease in NH4 and TN concentrations in the effluent of the HFCW system were observed with fluctuated removal efficiency (RE). Maximum RE for ammonia, TN, TSS, and COD was > 80%. Although showing a decreasing pattern during observation, phosphorus was not effectively removed by Heliconia psittacorum in the studied HFCW system. Cleaner effluent was observed than much dirty and black colour of influent. Heliconia psittacorum grew well with increased shoot height and numbers of new plant seedlings. The long-term observation was needed for Heliconia psittacorum in the HFCW system to reach a steady state and to examine its potential to remediate textile wastewater.
Statistical Assessment of Some Water Quality and Rainfall Data in Ciliwung River, Indonesia
Authors: Aisyah S , Hidayat H , Verawati D
Published: July 2022

Ciliwung is the river that flows from upstream in the Puncak area of Bogor Regency to Jakarta Bay. Water quality parameters have been monitored each month at three stations in the Ciliwung River watershed by the Indonesian Ministry of Environmental and Forestry and Meteorological, Climatological, and Geophysical Agency. The data analyzed in this study are rainfall and water quality data for the period 2017-2020 with water quality variables including pH, temperature, Dissolved Oxygen (DO), electrical conductivity (EC), Turbidity, Total Dissolved Solids (TDS), and Nitrate-N. This paper aimed to analyze the time series data using statistical methods and describes certain chemical parameters and rainfall data, that show Ciliwung water quality during 2017-2020. Descriptive analysis was used to determine the mean, skewness, and kurtosis values based on time and location. Histogram and boxplot graphs were used to describe distribution of the data set. Test of Kolmogorov-Smirnov was used to evaluate the normality of the data set. The descriptive analysis resulted in the mean of each water quality parameter showing a value that did not show a significant difference between observation locations except for the TDS parameter. From the histogram and boxplot graphs, it can be seen that the data shows an abnormal distribution and there are many outliers. Kolmogorov-Smirnov test resulted in better normality of data distribution. The main problem of pollution is the use of oxygen by organic matter contained in river water. Ciliwung River downstream was changed into open accumulator wastewater from the food industry, livestock, and settlements.
Mangrove Resource and Ecotourism Development in Karangsong, Indramayu Regency, West Java, Indonesia
Authors: Novianti R , Afandi AY , Tampubolon BI , Rahmadya A , Sulawesty F
Published: July 2022

Karangsong ecotourism is one of the mangrove forests successfully conserved through the co-management of the government and local communities. The rehabilitation process which started in 2008 has positively impacted the environment, especially aquaculture. Mangrove forest conservation managed by the Pantai Lestari Group has opened opportunities in the ecotourism sector that attracts over 50,000 visitors yearly, thereby significantly impacting the area’s social and economic impacts. However, there are negative impacts associated with the development of mangrove conservation areas into tourist sites, especially the balance between economic and conservation aspects. Therefore, descriptive analysis was used to determine the overview of Karangsong mangrove resources, background tourism status, highlight community, and institutions’ involvement. SWOT analysis is used to describe the potential and challenges of its ecotourism management. The result showed that support is needed from other stakeholders who care about the sustainability of the mangrove ecosystem by prioritizing aspects of environmental carrying capacity for conservation area management. It is necessary to conduct further research as a support for sustainable ecotourism and determine the right ecotourism development strategy for the future based on the identification of the potential of Karangsong natural resources.
Calcium supplementation of bioinks reduces shear stress-induced cell damage during bioprinting
Authors: Fischer Lena , Nosratlo Mojtaba , Hast Katharina , Karakaya Emine , Ströhlein Nadine , Esser Tilman U , Gerum Richard , Richter Sebastian , Engel F B , Detsch Rainer , Fabry Ben , Thievessen Ingo
Published: July 2022

During bioprinting, cells are suspended in a viscous bioink and extruded under pressure through small diameter printing needles. The combination of high pressure and small needle diameter exposes cells to considerable shear stress, which can lead to cell damage and death. Approaches to monitor and control shear stress-induced cell damage are currently not well established. To visualize the effects of printing-induced shear stress on plasma membrane integrity, we add FM 1-43 to the bioink, a styryl dye that becomes fluorescent when bound to lipid membranes, such as the cellular plasma membrane. Upon plasma membrane disruption, the dye enters the cell and also stains intracellular membranes. Extrusion of alginate-suspended NIH/3T3 cells through a 200 µm printing needle led to an increased FM 1-43 incorporation at high pressure, demonstrating that typical shear stresses during bioprinting can transiently damage the plasma membrane. Cell imaging in a microfluidic channel confirmed that FM 1-43 incorporation is caused by cell strain. Notably, high printing pressure also impaired cell survival in bioprinting experiments. Using cell types of different stiffnesses, we find that shear stress-induced cell strain, FM 1-43 incorporation and cell death were reduced in stiffer compared to softer cell types and demonstrate that cell damage and death correlate with shear stress-induced cell deformation. Importantly, supplementation of the suspension medium with physiological concentrations of CaCl2 greatly reduced shear stress-induced cell damage and death but not cell deformation. As the sudden influx of calcium ions is known to induce rapid cellular vesicle exocytosis and subsequent actin polymerization in the cell cortex, we hypothesize that calcium supplementation facilitates the rapid resealing of plasma membrane damage sites. We recommend that bioinks should be routinely supplemented with physiological concentrations of calcium ions to reduce shear stress-induced cell damage and death during extrusion bioprinting.
A three-dimensional human adipocyte model of fatty acid-induced obesity
Authors: Pieters Vera M , Rjaibi Saifedine T , Singh Kanwaldeep , Li Nancy T , Khan Safwat T , Nunes Sara S , Dal Cin Arianna , Gilbert Penney M , McGuigan Alison P
Published: July 2022

Obesity prevalence has reached pandemic proportions, leaving individuals at high risk for the development of diseases such as cancer and type 2 diabetes. In obesity, to accommodate excess lipid storage, adipocytes become hypertrophic, which is associated with an increased pro-inflammatory cytokine secretion and dysfunction of metabolic processes such as insulin signaling and lipolysis. Targeting adipocyte dysfunction is an important strategy to prevent the development of obesity-associated disease. However, it is unclear how accurately animal models reflect human biology, and the long-term culture of human hypertrophic adipocytes in an in vitro 2D monolayer is challenging due to the buoyant nature of adipocytes. Here we describe the development of a human 3D in vitro disease model that recapitulates hallmarks of obese adipocyte dysfunction. First, primary human adipose-derived mesenchymal stromal cells are embedded in hydrogel, and infiltrated into a thin cellulose scaffold. The thin microtissue profile allows for efficient assembly and image-based analysis. After adipocyte differentiation, the scaffold is stimulated with oleic or palmitic acid to mimic caloric overload. Using functional assays, we demonstrated that this treatment induced important obese adipocyte characteristics such as a larger lipid droplet size, increased basal lipolysis, insulin resistance and a change in macrophage gene expression through adipocyte-conditioned media. This 3D disease model mimics physiologically relevant hallmarks of obese adipocytes, to enable investigations into the mechanisms by which dysfunctional adipocytes contribute to disease.
Theoretical analysis of beam quality degradation induced by laser spectral characteristics in spectral beam combining system
Authors: Xian Yuqiao , Yang Yifeng , Li Binglin , Liu Meizhong , He Bing , Zhou Jun
Published: July 2022

We establish a model based on the dispersion of the diffractive grating to investigate the influence of the spectral envelope and wavelength stability on the combined beam quality M
2 of the spectral beam combining (SBC) system. We obtain the analytic expressions of combined beam quality corresponding to the second-moment-spectral width of the beamlets, which can be used to forecast the combined beam quality for any integrable spectral envelope shape of beamlets in an SBC system. Additionally, we find that the center wavelength shift of beamlets has a significant impact on the combined beam quality. The second-moment-based width of the center wavelength shift distribution among all beamlets should be less than 0.5 times the spectral width. Here, the spectral width is the weighted root mean square of all beamlets’ spectral width, where the weight is the power of each single channel.
Analysis of surface quality and optimization of process parameters in laser-assisted cutting of SiC ceramics
Authors: Dai Di , Zhao Yugang , Cao Chen , Liu Qian , Liu Guangxin , Song Zhuang , Zhang Xiajunyu , Zheng Zhilong , Zhang Haiyun , Dong Ruichun
Published: July 2022

In order to improve the surface quality of laser-assisted turning silicon carbide (SiC) ceramics, the effects of laser power, rotational speed, cutting depth and feed speed on surface quality are investigated. Taking the surface roughness as the characterization value, the reasonable selection range of each factor is determined by the numerical simulation results of temperature field and the single factor experiment results; orthogonal experiments and range analysis are performed on laser power, rotational speed, cutting depth and feed speed, the primary and secondary order of influence on surface roughness and the optimal combination of process parameters are obtained. The surface topography of the cutting area was observed by 3D digital microscope and the surface roughness is calculated. Taking surface roughness as the evaluation index, the reasonable selection range of each factor is obtained through temperature field simulation and single factor experiment results analysis as follows: laser power 230 ∼ 245 W, rotational speed 1500 ∼ 1650 r min−1, cutting depth 0.1 ∼ 0.2 mm, and feed speed 2 ∼ 4 mm min−1. Through orthogonal experiment and range analysis, the order of the significant degree of the influence of various process parameters on surface roughness and the optimal combination of process parameters are obtained. The order of the significant degree of the influence of various process parameters on surface roughness Ra is as follows: laser power (P) > cutting depth (ap) > feed speed (f) > rotational speed (n); the optimal combination of process parameters is as follows: laser power 235 W, rotational speed 1620 r min−1, cutting depth 0.1 mm and feed speed 2 mm min−1. Compared with the surface quality of original workpiece, the surface of the SiC workpiece processed under the optimal combination of process parameters has no cracks and damage marks, and the surface roughness is reduced to 0.293 μm, which significantly improves the surface quality of the SiC workpiece.
High temperature tribological and electrochemical behavior of heat-treated Al2O3-base hybrid coating sprayed by HVOF thermal spray technique
Authors: Sonia  , Walia R S , Suri N M , Chaudhary Sumit
Published: July 2022

In the present study, the hybrid coating was developed by HVOF over the cast iron substrate. The hybrid coating material comprises Al2O3 (80% w/w) enriched with graphite, MoS2, and fumed silica in w/w of 5%, 10%, and 5% respectively. Microstructure and phase composition of prepared coated samples were analyzed by SEM-EDS, XRD and Raman Spectroscopy. The coated samples were heat-treated and their mechanical, electrochemical and tribological behavior was compared with the as-coated samples. There was a considerable change observed in the micro-hardness and anti-corrosion properties of the coated material after heat treatment. The residual stresses in the heat-treated sample decreased compared to the as-coated sample. The high-temperature tribological investigation was carried out in non-lubricated conditions at three different temperatures 30 °C, 150 °C, and 300 °C with a constant load of 40 N and variable sliding speed. The coefficient of friction and wear rate was calculated and it was found that there was a decrement up to 36% in the wear rate of the heat-treated samples compared to the as-coated sample. The SEM morphologies of the wear track showed the presence of small cracks, adhesion, abrasion and smear regions due to plastic deformation.
Mechanical characterization of solder interconnections on functionalized, copper-containing polymer thick-film pastes for hybrid integration
Authors: Hümmer Michael , Roudenko Jewgeni , Wenger Thomas , Reichenberger Marcus
Published: July 2022

In this work, on different substrate materials thermally cured polymer thick-film (PTF) pastes are connected to surface mount technology resistors using a SnBiAg solder alloy. The effect of substrate pre-treatment with atmospheric plasma and thermal cycling on the shear strength of these interconnections is investigated, and the shear forces obtained are graded using United States Defense Standard / Military Standard (MIL-STD) 883. In particular, the build-up of solder interconnections on conductive structures made of commercially available copper-containing PTF pastes and their mechanical characterization is novel. As well as the mechanical characterization of conductive structures, made of PTF pastes, on plasma-treated substrates and their grading using the MIL-STD 883. In addition, interconnections with silver-containing conductive structures are realized for comparison. Depending on the interconnection system, component mean shear forces of up to 31 N are achieved. While some systems meet the 1.25× criterion of MIL-STD 883, the majority of the systems investigated do not meet the 1.00× criterion. Hereby, the adhesion between the conductive structure and the substrate usually fails. Plasma pre-treatment shows an adhesion-increasing effect only for a proportion of substrate materials used, as does thermal aging. But thermal loads can also impair the adhesive strength.
Tuning the topological band gap of bismuthene with silicon-based substrates
Authors: Wittemeier Nils , Ordejón Pablo , Zanolli Zeila
Published: July 2022

Some metastable polymorphs of bismuth monolayers (bismuthene) can host non-trivial topological phases. However, it remains unclear whether these polymorphs can become stable through interaction with a substrate, whether their topological properties are preserved, and how to design an optimal substrate to make the topological phase more robust. Using first-principles techniques, we demonstrate that bismuthene polymorphs can become stable over silicon carbide (SiC), silicon (Si), and silicon dioxide (SiO2) and that proximity interaction in these heterostructures has a significant effect on the electronic structure of the monolayer, even when bonding is weak. We show that van der Waals interactions and the breaking of the sublattice symmetry are the main factors driving changes in the electronic structure in non-covalently binding heterostructures. Our work demonstrates that substrate interaction can strengthen the topological properties of bismuthene polymorphs and make them accessible for experimental investigations and technological applications.
The commercialisation of fusion for the energy market: a review of socio-economic studies
Authors: Griffiths Thomas , Pearson Richard , Bluck Michael , Takeda Shutaro
Published: July 2022

Progress in the development of fusion energy has gained momentum in recent years. However, questions remain across key subject areas that will affect the path to commercial fusion energy. The purpose of this review is to expose socio-economic areas that need further research, and from this assist in making recommendations to the fusion community, (and policy makers and regulators) in order to redirect and orient fusion for commercialisation: When commercialised, what form does it take? Where does it fit into a future energy system? Compared to other technologies, how much will fusion cost? Why do it? When is it likely that fusion reaches commercialisation? Investigations that have sought to answer these questions carry looming uncertainty, mainly stemming from the techno-economics of emerging fusion technology in the private sector, and due to the potential for applications outside of electricity generation coming into consideration. Such topics covered include hydrogen, desalination, and process-heat applications.
Analysis of pressure at transition zone of valve plate of radial piston pump
Authors: Kumar Lokesh , Mandal Nimai Pada
Published: July 2022

In present studies focuses on the characteristics of flow-pressure of piston cylinder barrel and silencing groove chambers near the transition zone of valve plate of a fixed displacement radial piston pump. The designing of silencing groove of valve plate of the pump is carried out with appropriate geometrical configuration, compute the orifice area of piston kidney over the silencing grooves and manifolds, the interaction area make a key role in fluid flow interaction. The pressure and flow of pump is analyzed in consideration the silencing groove as separate control volume from manifold, each silencing groove chamber is connected to the both end of the manifold chamber, the shape of the silencing groove is an asymmetric tetrahedron. The radial piston pump is modelled in simulation with consideration of five pump pistons barrel, analyses the pressures near at transition zone with different bridge angle. The flows interaction of pump piston cylinder barrel with silencing groove chamber and manifold chamber are also carried out. The overall pump volumetric efficiency, flow and pressure fluctuation of radial piston pump are analyzed to optimize the pump.
Study of the mechanical, wear and corrosion behaviour of silicon nitride nanoparticles reinforced copper surface composite through friction stir processing
Authors: Raja R , Jannet Sabitha , Aby Joel , Ebenezer Jacob Dhas D S
Published: July 2022

The present work is focused on synthesizing Copper/Silicon Nitride (Si3N4) Nano Surface Composite (NSC) by friction stir processing. All the four copper plates had a groove width of 0.6, 0.9, and 1.2 respectively. A dual-pass FSP was carried out, the rotational speed of the tool is 1400 rpm, an axial force of 10 k N, and a traverse speed of 15 mm min−1. The microstructure and the distribution of silicon nitride nanoparticles were studied using a field emission scanning electron microscope (FESEM). The results indicate that the tensile strength of Cu/Si3N4 NSC increased and they exhibit superior micro hardness, corrosion resistance, and wear resistance compared to pure copper.
Computational analysis to study the effect of selenization on ZrS2/CZTS heterostructure performance
Authors: Gupta Shubhra , Shishodia Gayatri , Shishodia P K
Published: July 2022

Solar Cell Capacitance Simulator(SCAPS) program has been used to study JV characteristics and spectral response of ZrS2/CZTSSe heterostructure. The proposed cell performance has also been compared with ZrS2/CZTS and ZrS2/CZTSe junctions. In the present study, performance parameters have been calculated by varying Se concentration with an exponential grading law in SCAPS for ZrS2/CZTSSe heterostructure. CZTSSe bandgap can be easily tuned by varying the Se and S content. Optimized composition ratio of S/(S + Se) presented an efficiency of 16.50% and the simulated results have been interpreted for higher content ratio of 0.44. At this composition, short circuit current density, open circuit voltage and fill factor attained were 35.54 mA cm−2, 0.6342 V and 73.23% respectively. The influence of layer thickness, bulk defect density, electron affinity and relative permittivity on solar cell performance parameters have also been studied.
Effect of external electric potential on the mechanical resonance of MEMS cantilever resonator
Authors: Deshmukh Ayush , K P Rao Venkatesh
Published: July 2022

This work presents an analytical model to predict the natural frequency of electrostatically actuated micromachined cantilever beam under the application of DC voltage. The analytical modelling uses an energy based method with a sinusoidal vibration assumption. The electric field between the cantilever electrodes is assumed to be vertical and fringing field effects are neglected. The behaviour of natural frequency and a closed-form expression for pull-in voltage are evaluated. The electrostatic spring softening effect of DC bias on the resonant natural frequency is studied in particular. Results are compared with simulation in ANSYS.
An efficient and high gain switched-capacitor based multi-level inverter
Authors: Anand Ravi , Mandal Rajib Kumar
Published: July 2022

A new switching-capacitor-based boosting multilevel inverter is described in this paper. A nine-level voltage waveform is produced using 10 switches, one-diode, and two-capacitors. Each fundamental cycle contains numerous occurrences of capacitor voltages being linked in parallel with the source voltage, resulting in self-balancing capacitor voltages. Proposed topology has built in polarity changing ability so no H-bridge is required. This paper describes a simple pulse-width modulation system based on logic gates that maintains power balance among the capacitors. For obtaining the higher voltage gain extended topology of proposed topology is also presented. The prototype’s experimental results are provided for verifying the working and boosting capability by four times of source voltage. A thorough comparison with contemporary topologies demonstrates the cost-effectiveness of the suggested topology, as well as the fact that it is a simpler construction that requires less space and consumption of resources.