bluuebunny/crossref_metadata_2025 huggingface dataset:
1st International Conference on Physical Problems of Engineering (1st ICPPE)
Authors: Ruge J C , Torres-Ramírez J E , Barba-Ortega J , Dueñas L M , V-Niño E D
Published: November 2021

The reciprocal contribution that physics has had in engineering and engineering in physics is undeniable. The First International Conference on Physical Problems of Engineering (1st ICPPE) tries to highlight this symbiotic relationship between both sciences through different presentations that reflected their results in separate articles that will be published in the Journal of Physics: Conference Series.

List of Organizing Committee, National Scientific Committee, International Scientific Committee, Sponsor, Partners, Images are available in this pdf.
Flow hydraulic simulation through two sand traps, using Ansys fluent
Authors: Rodríguez C D , De Plaza J S
Published: November 2021

Computational fluid dynamics is a tool that allows to simulate and observe the behavior of any fluid, based on a physical, hydraulic, and hydrodynamic analysis. This research analyses the behavior of the flow in a sand trap, which is a structure used to remove sand particles with a minimum size of 0.10 mm, prior to treatment in a drinking-water plant. The objective of this study is to determine the highest efficiency between two sand traps, one with a double smooth screen and the other with a double perforated screen (with diffusers), based on the simulation and analysis behavior of the flow inside each sand trap. The methodology used includes the traditional design of each unit based on Hazen’s model and Stokes viscosity law, to later carry out the numerical model simulation from Ansys Fluent (pre-processing, processing, and post-processing). The result shows that perforated double screen sand trap generates a removal efficiency of 78%, while the smooth double screen 28%. In addition, other four units of interleaved screens are proposed, in these cases efficiencies of up to 50% are observed and it is shown that it is necessary to implement at least two perforated screens (with diffusers) to guarantee an efficiency greater than 70%. Hydraulic simulation has a broad impact on infrastructure works and consulting.
Differential microwave sensor based on microstrip lines loaded with a split-ring resonator for dielectric characterization of materials
Authors: Zapata-Londoño J , Umaña-Idárraga F , Morales-Guerra J , Arias-Gómez S , Valencia-Balvin C , Reyes-Vera E
Published: November 2021

In this work, we propose a microwave sensor that allows the characterization of dielectric materials based on a differential configuration. A microstrip permittivity sensor of the surrounding material is proposed using a split ring-resonator to measure differentially. The geometry was optimized and was numerically analyzed using CST STUDIO. The numerical analysis of the metamaterial unit cells is carried out first, to determine the operating band. After that, the metamaterial cell was employed to design the differential microstrip permittivity sensor. The obtained results reveal that the proposed sensor has the capability to characterize different materials whose relative dielectric permittivity’s are in the range of 9.8 to 80 with great performance. The device has a total size of 86 mm × 60 mm and operates around 3 GHz. In this band, the sensor reaches a sensibility of 2.89 MHz and a Q-factor of 70.15. Thus, this work shows a compact, reusable, label-free, and non-destructive microwave sensing device and paves the way for high accuracy sensing of the dielectric properties of different materials due to its high- Q-factor as well as high sensitivity.
Fluid-dynamic study of the behavior of the air inside a textile Stenter
Authors: Parra J W , Quadri M B , Rodríguez D C
Published: November 2021

In the textile industry, drying is one of the most important processes. This process requires large investments and high energy consumption, which generates high costs for companies in this sector. In this work, a modeling of the behavior of the air was carried out in a textile Stenter, under real operating conditions through the development of fluid-dynamic simulations. For the computational modeling of the problem, a 3D geometry was constructed based on measurements taken from an injector of a textile Stenter. The standard k-ε turbulence model was used in the turbulent flow solution. The equations of the model were solved numerically using the finite element method. The standard k-ϵ turbulence model proved to be a model capable of reproducing the behavior of the air in the injectors of the textile Stenter.
Influence of the formulation of a flux-cored wire on the microstructure and hardness of welded metal
Authors: Amaral E C , Jácome-Carrascal J L , Moreno-Uribe A M , Bracarense A Q
Published: November 2021

For this paper, the microstructure and hardness of the weld metal were investigated by conducting experiments with the flux cored arc welding process in underwater and air conditions. A rutile/oxidizing tubular wire was used, manufactured by the Robotics, Welding and Simulation Laboratory at Minas Gerais Federal University, especially for underwater wet welding. Underwater welds had a lower volumetric fraction of acicular ferrite in the weld metal compared to air welds. In the thermally affected zone, for both welds, there was a predominant formation of martensite. However, the grain size and width of the thermally affected zone of underwater welds are smaller. The hardness values shown correspond to the microstructure formed in the weld metal. On the other hand, in the region of the thermally affected zone, the hardness values were higher underwater welds, due to the smaller martensite grains presented.
Evaluation of mineral oils as matrices for AISI/SAE–1020 steel naphthenic corrosion study
Authors: Conde-Rodríguez G R , Sanabria-Cala J A , Mancilla Estupiñán R A , Laverde Cataño D A , Núñez Castañeda M C
Published: November 2021

Petrochemical industry has suffered great economic impact due to light crude oil reserves reduction, so refineries have been processing high acidity heavy crude oils. Studies of corrosion caused by naphthenic acids are interfered by presence of other corrosive agents contained in real crude oils, so naphthenic phenomenon must be isolated using synthetic crude oils. For this reason, in present work two high purity mineral oils were used to evaluate their efficiency as synthetic crude oil matrices in AISI/SAE–1020 steel naphthenic corrosion study. Temperature levels evaluated were 200 °C, 250 °C, and 300 °C, while exposure times evaluated were 5, 10 and 15 hours. Surface morphological characterization of AISI/SAE–1020 steel was carried out using scanning electron microscopy and X–ray diffraction. Gravimetric tests showed that AISI/SAE–1020 steel naphthenic corrosion rate increases with temperature and exposure time for one of the synthetic crude oils. However, results obtained for the other synthetic crude oil did not show increasing behaviour due to presence of sulfur traces in the oil, which caused an interference with AISI/SAE–1020 steel naphthenic corrosion study, reducing the reliability of gravimetric results so they cannot be extrapolated to operating conditions in distillation units.
Durability assessment of concretes reinforced with steel and synthetic fibers in Colombia
Authors: Carrillo J , Guerrero N , Arroyo O , Rodríguez A
Published: November 2021

In recent years, the use of steel fibers has increased in Colombia, optimizing structure designs, quality specifications and mechanical behavior. However, the concrete durability and resistance to aggressive environments such as sulfates and chlorides are not commonly evaluated. This paper includes results of durability analysis for 21 MPa compressive strength concretes reinforces with steel and synthetic fibers. Performance parameters measured during tests include sulfate resistance, chlorides penetration, and carbonation according to technical standards. The Variables of experimental program were fiber type and fiber dosage. Dosages for synthetic fibers were 1.5 kg/m3, 3.0 kg/m3 and 5.0 kg/m3, and for steel fibers were 5.0 kg/m3, 9.0 kg/m3 and 18 kg/m3. Results of the study were used to propose recommendations for reducing concrete deterioration when exposed to these aggressive environments and for extending the durability service life.
Numerical study of the physical processes of gas leakage in the compression ring in diesel engines
Authors: Pabón León J A , Rojas Suárez J P , Orjuela Abril M S
Published: November 2021

In this research, the construction of a numerical model is proposed for the analysis of the friction processes and the thickness of the lubrication film present in the compression ring of internal combustion engines. The model is built using MATLAB software, and three load conditions are used as reference (2 Nm, 4 Nm, and 6 Nm) with a rotation speed of 3600 rpm, which correspond to a stationary single-cylinder diesel engine. Comparison between model estimates and experimental results show that the development model could predict the actual engine conditions. The deviation between the numerical model and the experimental data was 17%. It was shown that the increase in engine load causes a 16% increase in the friction force of the compression ring, which implies a 50% increase in power loss due to friction processes. In general, the model developed allows the analysis of the friction processes in the compression ring and its effect on the lubrication film, considering the leakage of the combustion gases. In this way, the construction of a more complex mathematical model is achieved, which allows improving the precision in the analyzes related to the interaction between the compression ring and the cylinder liner.
Using implementation of artificial intelligence in estimating the exchange rate in the foreign exchange market
Authors: Devia Narvaez D F , Ospina R , Mesa F
Published: November 2021

The Foreign Exchange currency market is considered the most liquid market in the world due to the amount of money that is traded every day. Researchers and investors are interested in having a system that allows predicting the direction of the exchange rate of a pair of currencies in order to create a strategy that allows them to profit from the market. Since the movement of the exchange rate between currencies generates a high frequency time series, recurrent neural networks have gained strength in the prediction of these markets, since they have the characteristic of generating models of non-linear systems. In this document, the study of the prediction of the direction of the exchange rate of different currencies was carried out using the recurrent auto-regressive neural network with exogenous inputs, which has the characteristics to obtain a predictive model of a time series. The tests were carried out in the Euro / Dollar pair in the time frame of one hour, demonstrating the potential of this neural network architecture. These techniques are products of the biological and physical sciences in industrial processes.
Energy lost in endothermic reactions in the production of clay blocks in a continuous kiln
Authors: Guerrero Gómez G , Afanador García N , Nolasco Serna C
Published: November 2021

In Ocaña, Norte de Santander, Colombia, the production of ceramic materials is done in a traditional and empirical manner, generating heat losses, low productivity and product quality, and increased emissions of polluting gases into the environment. A virtual instrument for temperature data acquisition was developed and the firing process was monitored in two loading doors of a Hoffman kiln. 29040 blocks were produced, and 1370.76 kg of pulverized charcoal were consumed. The firing process lasted sixty-two hours and the virtual instrument was programmed to record data every 5 minutes. The energy supplied to the brick kiln was 340.16x106 kJ and the heat due to loading of the products and heat lost in the endothermic reactions of the clay was 107.71x106 kJ and 105.71x106 kJ respectively, representing 31.66% and 31.08% of the energy supplied. The results have made it possible to establish trends in the temperatures and energy consumed in the endothermic reactions in the clay. This will allow the implementation of coal quality and grinding procedures, increasing energy efficiency, and reducing gas emissions into the environment, thus avoiding acute respiratory diseases.
Analysis of the application of physics in the design and construction of architectural projects. The Eiffel Tower
Authors: González-Almeyda J D , Ayala-Garcia E T , Prada-Nuñez R
Published: November 2021

This article studied the impact and application of physical concepts in the design and construction of the Eiffel Tower in Paris, an architectural reference that implemented physical concepts in its structural design. A documentary methodological framework was used to establish the importance of the Eiffel Tower in the universal exposition of Paris in 1989 and, to carry out the structural analysis of the work; a quantitative-descriptive approach was used for the recognition of the basic concepts of physics from architecture according to gender, through a survey as a research instrument developed under non-probability and convenience sampling, which was applied to students of Architecture of the Universidad Francisco de Paula Santander, Colombia, in order to determine the knowledge of basic physics by students. The results of this research showed that the Eiffel Tower represents a milestone in architecture where physical concepts such as tension, compression, traction, aerodynamics, and torque were applied. Finally, it was evidenced that the students who participated in this study recognize the importance of applying the basic concepts of physics in architecture; fact by which it is recommended to encourage the study of physics, to strengthen the technological component of Architecture.
Conjoint analysis of consumer preferences for pineapple fruit in Labuhan Batu District, North Sumatra
Authors: Hernosa S P , Siregar L A M , Hanum C , Supriana T
Published: November 2021

This study aims to determine consumer characteristics and attributes, and level of pineapple fruit, which are consumers’ preferences in Labuhan Batu District, North Sumatra Province. The largest peatland is on the east coast, namely in the Labuhan Batu District area of 192 thousand ha. Some research results support that pineapple is tolerant of high soil acidity levels, adaptive to peat swampland that is tolerant of pH 3‒4. Based on this, pineapple is a potential plant in Labuhan Batu District, so sustainable pineapple cultivation is needed. By understanding the characteristics, attributes of pineapple level, from consumer preferences, it is hoped that marketing and determining sales strategies can be adjusted to market demand: methods, conjoint analysis. The characteristics of the consumers used are gender, age, education level, type of work, family income per month, number of family members, and purchase frequency for attributes, taste, size, taste, color, and texture. The results of the study, the characteristics of age 25‒44 are consumers who consume the most pineapples. The combination of pineapple fruit that consumers like, fruit with a sweet taste, large size, strong taste, soft and smooth texture, and yellowish-green color. This can be considered in determining the target market and marketing strategy for pineapple in Labuhan Batu District, North Sumatra Province.
Transformation of labor participation on off-farm diversification: insights from rural households in Indonesia
Authors: Asih D N
Published: November 2021

This study analyses the rural transformation and the determinants of off-farm work diversification in Indonesia. Based on employment growth, the study explores the transformation of the labour sector to off-farm work as an alternative income source in mitigating the decreasing carrying capacity of the agricultural sector. Using a panel data set from rural households in Central Sulawesi, the study applied a random logit model to account for the determinants of off-farm participation and economic mobility over time. The results show that crop failure is a key driver of off-farm work diversification which is further compounded by several factors including asset holdings, the age and education level of the household head by 51.1%, 21.77%, 1.59% and 18.59% respectively. These results confirm that ‘these push’ factors are motivating the rural household on off-farm labour allocation, which indicate the implications of economic transformation through the diversification of income sources and labour allocation away from agriculture subsystems in rural areas in Indonesia.
Factors affecting sustainability of agricultural machinery assistance program
Authors: Azis M , Saputra Y H , Setiyanto A
Published: November 2021

One of the Ministry of Agriculture’s efforts to support agricultural development is by providing equipment and machinery assistance. There are many multi-dimensional problems, both technical, socio-cultural, economic, and environmental. This study aimed to analyze the sustainability status of the agricultural equipment and machinery assistance program. This research was conducted in 2020 with the object of the two-wheeled tractor and four-wheeled tractor assistance program in 2018-2019. Research location covers six districts, the selection of site determined by the provinces considered the most successful and the least successful in realizing activities. The sustainability status of the activity program was analyzed using Multidimensional Scale Analysis. The collected data and information through structured questionnaires from 47 institutional respondents and literature studies, both printed and electronic. The results showed that agricultural equipment and machinery assistance program (TR2 and TR4) was less sustainable. The comparison of the MDS value and Monte Carlo’s analysis was 49.93, with an R2value of 89%. The S-Stress statistical test is still relatively high, namely 0.30 (above 0.25), which means improvements and refinement needs from the implementation aspect. Improvements from various elements are divides into two groups. First, leverage factors that encourage the sustainability and success of the implementation of activities, and the second is the improvement of the performance of TR2 and TR4 beneficiary groups. Policy recommendations for implementing future program activities are a strict selection of potential beneficiaries and improvements in the management aspects of beneficiaries at the farmer level by providing guidance.
The characteristics and tourism destination criteria of coffee plantation agritourism
Authors: Wiyono S N , Kusumo R A B , Syamsiyah N , Rochdiani D , Kumoro P S
Published: November 2021

The coffee plantation agritourism (CPA) is one of the new type of tourism destinations in West Java, Indonesia. The application of sustainable agritourism is used as an effort to increase the number of tourists who are interested in nature tourism. At this CPA the number of tourists is still low and has not implemented sustainable agritourism. The puIDRoses of this study is to identify this agritourism’s characteristics that referred to the perception of tourists towards CPA “K Farmers” and the “K Farmers” achievements of the indicators of sustainable tourism destinations. The methodology of the study is case study by a qualitative design. The result of this study showed that the perception of tourists “K Farmers” is in high level with a perception index value of 33, so it can be concluded that the perception of tourists to Coffee Tourism “K Farmers” is “good”. The criteria of sustainable tourism destinations according to the guidelines from the Minister of Tourism Regulation, CPA “K Farmers” has been and is developing with almost all the criteria in the regulation, but there are still criteria that have not been met by “K Farmers”. This research implies that agritourism business owners need to pay attention to sustainable destination guidelines as a reference in developing their business and meeting the adaptation requirements of climate change, tourism asset and attraction records, access for all, crisis and emergency management.
Assessment of the success factors influencing of rice-fish farming innovation village to support food security
Authors: Triyanti R , Suryawati S H , Wijaya R A , Wardono B , Hafsaridewi R
Published: November 2021

In the current condition in the village, the community is faced with limited agricultural land and the unpromising sustainability of conventional rice businesses, so that agricultural business is less attractive to the community. The solution that can be done by the community is to build a rice-fish farming innovation village. This study aims to analyze rice-fish farming in terms of social and economic aspects and to analyze the factors that influence the success of the rice-fish farming innovation village for food security and community welfare. This research was conducted from October to December 2020 in Samberembe, Candibinangun Village, Sleman District, Special Region of Yogyakarta. The research approach used a mixed-method, with data analysis using business analysis, descriptive analysis, and prospective analysis. The results showed that an integrated rice-farming program can increase farmers’ income up to IDR 35 million per 1,000 m per year and changing the socio-technical at every phase of cultivation. The success of the rice-fish farming innovation village can be realized with the following key factors (1) a good technical irrigation system, (2) a continuous supply of superior fish seeds, (3) strengthening of rice-fish farming innovation technology, and (4) strengthening of pest eradication technology (beaver). This key factor can be considered as a national scale reference for the development of the rice-fish farming innovation village. The implication of the study is to create a superior and sustainable village that can improve community food security and local economy growth.
The implementation and synergy of Indonesian national food reserves
Authors: Yulianis N , Sarastuti  , Risfaheri  , Rachman B
Published: November 2021

In aggregate, Indonesia’s national food reserves (rice) in early 2021 are adequate, as indicated by the stock to use ratio (SUR) reaching 25.16% above the FAO recommendation of 17‒18%, with the end of 2020 rice stock reaching 7.9 million tons from 29.3 million tons rice consumption needs. As mandated by Food Law 18/2012, Indonesia has established a multi-layered mechanism of national food reserves, consist of a central government food reserve, regional government food reserves (provincial, district/city, and village level), and community food reserves. This paper aims to examine the various implementation of Indonesia’s national rice reserves along with synergy recommendations to strengthen government, regional governments, and community’s food reserves. The approach used is descriptive qualitative analysis, by exploring information and secondary data across institutions with national and regional coverage. The results of the study show: (1) the need for an increase in Central Government Rice Reserves (CGRR) in the range of 1.5‒2 million tons accompanied by strengthening the mechanism to absorb farmers production of unhulled rice/rice to stabilize rice prices especially at the peak harvest time; (2) strengthening the intensity of advocacy and coordination amongst key-stakeholders in provincial and district/city to optimize the implementation of government food reserves area; and (3) strengthening and developing village-based community food barns through cooperation with the Strategic Command for Rice Mill Development (Kostraling) and Village Owned Enterprise (BUM Desa and BUM Desma).
Sustainable management of smallholder oil palm farming during the COVID-19 pandemic
Authors: Nainggolan H L , Waruwu W S S , Gulo C K , Doloksaribu R C , Siahaan T M H
Published: November 2021

The emergence of the CoronaVirus Disease in 2019, until now has had a negative impact on various sectors of people’s lives including the agricultural sector. Smallholder oil palm farming has also experienced a negative impact due the pandemic. This research aims to knowing the situation of smallholder oil palm farming before and during pandemic; and to knowing the readiness of farmers to manage smallholder oil palm farming; and to knowing the sustainability of the management of smallholder oil palm farming during the pandemic. This research was conducted in STM Hilir Subdistrict, Deli Serdang District, North Sumatra, Indonesia, which was carried out in September - December 2020. The data used were primary and secondary data which were analyzed descriptively with income analysis method and simple tabulation. Based on the results of data analysis, concluded: smallholder oil palm farming during the COVID-19 pandemic was not stable, due to an increase in production costs of 20.2%/month, and a decrease income of farmers by 6.69%/harvest season/ha. In period of COVID-19 pandemic-19 59% of farmers said they are ready to develop their farming in a sustainable manner. Sustainable management smallholder oil palm farming during the pandemic is going well, based on indicators of ecological conservation, where farmers tend to use organic fertilizers. In accordance with the results of the study suggested; so that the government provides continuous counseling to farmers, provides incentives, subsidies for production facilities for farmers, so that farmers continue to apply health protocols in carrying out their farming activities.
Deteminant factors to improve Indonesian cocoa performance
Authors: Prasetyo A , Suswadi  , Aziez A F
Published: November 2021

Encouraging the growth of Indonesia’s agricultural sector is important for improving the export performance of Indonesia’s leading commodities. The purpose of the study was to determine the effect of the IDR exchange rate and the shock of the determinants of cocoa exports on the growth of Indonesian cocoa exports. The research was conducted using time series data from 1969-2017. This study uses the Vector Error Correction Model (VECM). The analysis showed that the data is stationary at the first difference. The causality test shows that cocoa production, IDR exchange rate, GDP affect the growth of Indonesian cocoa exports, but world cocoa prices have no effect on cocoa exports. The results of the impulse response factor (IRF) analysis show that the response of cocoa exports to changes in the exchange rate is more volatile when compared to the response of production, GDP, and world cocoa prices to Indonesian cocoa exports. Analysis of variance decomposition shows that the contribution of the IDR exchange rate to export growth is greater than the contribution of world cocoa prices, GDP, and production at the beginning of exports, however over time the influence of the IDR exchange rate will decrease and it is the number of production factors that will affect Indonesia’s cocoa exports. Indonesia needs to increase production by maintaining the quality of cocoa according to export needs considering the demand for cocoa that will continue to increase. Bilateral or multilateral cooperation is needed to strengthen cocoa export cooperation with major importing.
Developing agriculture value chain inclusive for small-scale vegetable farmers in the highland of Bedugul, Bali
Authors: Utama I M S
Published: November 2021

As a major global tourist destination, the demand for a large variety of fresh produce in Bali has developed following the country of origins of tourists and their eating habits. The varieties of fresh produce demanded by hotels and restaurants have increased since the 1970s. More than 100 types of vegetables (leafy and fruity vegetables, tubers, roots, shoots, immature flowers) and herbs are produced in the highland of Bedugul, Bali. As the market competition increases, the small-scale vegetable farmers have to be more value-oriented, efficient, and effective in production and postharvest handling. How is the competitiveness of the evolving value chain to meet the dynamic needs of institutional consumers and retail modern markets? Therefore, the aims of the study were to assess the competitiveness of the vegetables value chains and develop a model design of value chain inclusive for small scale farmers for improvement. This study was carried out through surveys and focus group discussions (FGD) involving actors in production and distribution channels. It was found that there were five groups of distribution channels,and most of them are less value-oriented. However, the emerging integrated value chains are shown, mainly to which derive from the institutional consumers (hotels and restaurants) and modern markets. A designed alternative model of value chain system inclusive for small-scale farmers has been developed, especially with the end on institutional consumers and modern markets.
Utilization of suboptimal land for the sustainability of upland rice farming in Minahasa District
Authors: Rawung J B M , Indrasti R , Hutapea R T P
Published: November 2021

Increasing rice production is not only relied on from irrigated and rainfed rice fields, but also on dry land (upland rice). Development of upland rice on sub-optimal lands is one of the efforts to overcome the problem of vulnerability to rice availability, but until now its management is still not optimal. Minahasa District is one of the upland rice producing districts in North Sulawesi. This paper aims to identify matters related to sub-optimal land use for the sustainability of upland rice farming by farmers that can be developed in support of efforts to increase upland rice production in North Sulawesi, in addition to improving the existing technology used by farmers. This study was conducted in the Tombariri Subdistrict, Minahasa District, using a survey method. Data collection was carried out through field observations, surveys, documentation, in-depth interviews with key informants, and literature studies. The data obtained were then analyzed descriptively. Based on field identification and the results of the study, it was found that the existing local farmers’ technology was still very simple, especially in the aspects of seed supply, planting and maintenance. Farmers are increasingly pursuing development towards organic farming. There are still many sub-optimal land uses that can be optimized for upland rice cultivation accompanied by improvements to the existing limiting factors on each land.
Computational investigation of the aerodynamic performance of reversible airfoils for a bidirectional tidal turbine
Authors: Giljarhus K E T , Shariatpanahi G S , Frøynes O A
Published: November 2021

A reversible airfoil is an airfoil that has equal performance when the flow is reversed. Such airfoils are relevant for many different applications, including use in ventilation fans, helicopter rotors, wind turbines and tidal turbines. Compared to traditional airfoils, reversible airfoils have different performance characteristics and have been less explored in the scientific literature. This work investigates the aerodynamic performance of some selected reversible airfoils using computational fluid dynamics. The selected airfoils are based on existing NACA 6 profiles and a profile using B-spline parameterization. The results show reduced performance for the reversible airfoils compared to a unidirectional airfoil. Of the investigated airfoils, the B-spline airfoil has the highest performance, with a maximum aerodynamic efficiency which is 87 % of the unidirectional design.
Comparison of unidirectional and bidirectional airfoils in a tidal stream turbine
Authors: Giljarhus K E T , Owolabi J O , Frøynes O A
Published: November 2021

Tidal stream turbines offer an attractive method for stable renewable energy generation. Due to the periodicity of the tidal stream, a tidal stream turbine can be designed to operate in a bidirectional manner, thereby avoiding a yaw control system. This article compares a unidirectional design with a bidirectional design to estimate the expected power loss for the bidirectional design. First, a blade-element momentum theory approach is used to find optimum pitch angles for the blades and give a low-cost estimate of the power production. Next, fully-resolved computational fluid dynamics simulations are performed to validate the BEMT approach and gain insight into the flow patterns. The two approaches estimate that the power output of the bidirectional design is approximately 15-20 % lower than for the unidirectional design. This suggests that although a bidirectional design will have some power loss compared to a unidirectional design it is an interesting alternative as it can yield the same power output for both the ebb and the tide. The study also serves as a starting point for further optimization of the bidirectional design.
Dual lidar wind measurements along an upstream horizontal line perpendicular to a suspension bridge
Authors: Nafisifard M , Jakobsen J B , Cheynet E , Snæbjörnsson J T , Sjöholm M , Mikkelsen T
Published: November 2021

Remote wind sensing can complement traditional anemometry at a bridge site and contribute to an improved wind-resistant design of long-span bridges. This study examines wind lidar measurement data recorded along a 168-meter-long horizontal line perpendicular to the main span of a suspension bridge in complex terrain. The velocity data records are obtained by a pair of continuous-wave Doppler lidars (short-range WindScanners) installed on the bridge deck. The measurement data are explored in terms of the mean wind speed and mean wind direction upstream of the bridge. The spectral characteristics of turbulence along the line are also investigated in relation to the increasing sampling volumes of a continuous-wave lidar system at increasing distances from the monitored area. Wind characteristics observed by the lidars are compared to those derived from sonic anemometer data recorded above the bridge deck at midspan. The results provide new insight into the wind flow characteristics in a fjord and demonstrate the potential of lidar measurements in charting the wind flow around a bridge. A slight monotonic increase of the wind speed, as well as a decrease in the yaw angle, is observed as the distance to the bridge reduces from 160 m to 20 m, while lower wind velocities are accompanied by a more stable wind direction. Within 15 m from the bridge deck, the adopted lidar setup gives unreliable information due to the large angle between the lidar beams.
Case study on advanced 3D finite element limit analysis of counter-acts installed at Ormen Lange
Authors: Olsen C L , Krabbenhøft K
Published: November 2021

The design of counter-acts for the Ormen Lange Northern Field Development has previously been considered in other publications. Counter-acts were used to ensure pipeline stability during pipe-lay along route curves. The counter-acts were large diameter steel cylinders installed with self-weight penetration. The in-place design was completed with use of advanced Finite Element Analysis (FEA) program Abaqus and validated in parallel by the finite difference (FD) program, FLAC. This paper will present a comparison of the previous work to advanced 3D Finite Element Limit Analysis (FELA) with use of the software OPTUM G3. 3D FELA is newly developed for geotechnical design. The paper will show the advantage of the FELA which is based on the principles of limit analysis. The counter-act design is particularly complex and given the cylindrical shape with no internal base plate. This will challenge the element types in the FELA model. Further, the soil conditions are amongst the softest clay encountered in Norway further increasing the complexity of the design.
Numerical investigations of flow around subsea covers at high Reynolds numbers
Authors: Yin G , Zhang Y , Ong M C
Published: November 2021

Two-dimensional (2D) numerical simulations of flow over wall-mounted rectangular and trapezoidal ribs subjected to a turbulent boundary layer flow with the normalized boundary layer thickness of δ/D = 0.73,1.96,2.52 (D is the height of the ribs) have been carried out by using the Reynolds-averaged Navier-Stokes (RANS) equations combined with the k – ω SST (Shear Stress Transport) turbulence model. The angles of the two side slopes of trapezoidal rib varies from 0° to 60°. The Reynolds number based on the free-stream velocity U
∞ and D are 1 × 106 and 2 × 106. The results obtained from the present numerical simulations are in good agreement with the published experimental data. Furthermore, the effects of the angle of the two side slopes of the trapezoidal ribs, the Reynolds number and the boundary layer thickness on the hydrodynamic quantities are discussed.
Burst pressure design of the cargo tank used in a novel large subsea freight-glider
Authors: Xing Y.
Published: November 2021

This paper presents the burst pressure design of the cargo tank used in the University of Stavanger (UiS) Subsea Freight-Glider (USFG). The USFG is an innovative large underwater cargo glider drone that is 50 m long and has a DWT of 1500 ton. It uses variable-buoyancy propulsion instead of traditional propellers for movement. This is an extremely efficient propulsion method and allows the USFG to achieve an average energy consumption of less than 10 kW. Structural weight is a premium as the USFG is required to be neutrally buoyant in water. Therefore, the design of the cargo tank which is the largest component in the USFG needs to be optimal for minimal structural weight. One approach used in design optimisation is to utilise design codes and/or methods that are more precise and therefore allow for lower safety margins. This approach will be investigated in this paper for the burst pressure design of the cargo tank. The different parts of ASME BPVC codes will be compared. The sensitivity of the codes to changes in design parameters is also investigated. Lastly, some comments on the use of reliability methods to further optimise the design are also presented.
Numerical study on deployment of subsea template using coupled and uncoupled model
Authors: Hauge N O , Li L
Published: November 2021

This study compares deployment of a subsea template simulated as a coupled model and as an uncoupled model in the time domain simulation software Orcaflex. Defining vessel motion as prescribed simplifies the model and will therefore also decrease the simulation time. Models with predefined vessel motions are called uncoupled models. Vessel motion in a coupled model is a continuously calculated reaction to the forces acting on the vessel. Some software might struggle to run coupled models. The deployment simulations are narrowed down to focus on the incident where the template crosses the splash zone when lifted with an offshore construction vessel. Noticeable differences between the allowable sea state results are observed from the two different simulation methods. Running the time domain simulation as an uncoupled model gives lower allowable sea states than the results from the coupled time domain simulation model.
Computational fluid dynamics simulation of buoyant mixing of miscible fluids in a tilted tube
Authors: Ghorbani M , Giljarhus K E T , Skadsem H J , Time R W
Published: November 2021

Buoyancy-driven flows and mixing of fluids with different densities occur frequently both in nature and as part of industrial processes within chemical and petroleum engineering. This work investigates the buoyant exchange flow of two miscible fluids in a long tube with closed ends at varying tilt angles using OpenFOAM. The study focuses on the evolution of the concentration field and front velocities of the mixing zone at different inclinations. Numerical results based on a miscible solver agree with previous experiments and direct numerical simulations. Treating the fluids instead as immiscible with no surface tension leads to unrealistically high front velocities at intermediate inclinations.
Prediction of dynamic mooring responses of a floating wind turbine using an artificial neural network
Authors: Bjørni F A , Lien S , Midtgarden T Aa , Kulia G , Verma A , Jiang Z
Published: November 2021

Numerical simulations in coupled aero-hydro-servo-elastic codes are known to be a challenge for design and analysis of offshore wind turbine systems because of the large number of design load cases involved in checking the ultimate and fatigue limit states. To alleviate the simulation burden, machine learning methods can be useful. This article investigates the effect of machine learning methods on predicting the mooring line tension of a spar floating wind turbine. The OC3 Hywind wind turbine with a spar-buoy foundation and three mooring lines is selected and simulated with SIMA. A total of 32 sea states with irregular waves are considered. Artificial neural works with different constructions were applied to reproduce the time history of mooring tensions. The best performing network provides a strong average correlation of 71% and consists of two hidden layers with 35 neurons, using the Bayesian regularisation backpropagation algorithm. Sea states applied in the network training are predicted with greater accuracy than sea states used for validation of the network. The correlation coefficient is primarily higher for sea states with lower significant wave height and peak period. One sea state with a significant wave height of 5 meters and a peak period of 9 seconds has an average extreme value deviation for all mooring lines of 0.46%. Results from the study illustrate the potential of incorporating artificial neural networks in the mooring design process.
Mathematical modelling of fluid flow in electromagnetically stirred weld pool
Authors: Enger K , Mousavi M G , Safari A
Published: November 2021

In this paper, a mathematical model has been proposed to study the relationship between electromagnetic stirring (EMS) weld parameters and the mode of fluid flow on grain refinement of AA 6060 weldments. For this purpose, fluid flow modelling using Navier-Stokes equation is described first, and then, the proposed mathematical approach has been discussed in detail. For demonstration, calculations to determine the fluid velocity in the weld pool of thin plate AA6060 were performed. The application of the model on the experimental results indicates that the best grain refinement is achieved at a transition mode from laminar to turbulent fluid flow.
Experimental investigation and ANN prediction for part quality improvement of fused deposition modeling parts
Authors: Tura A D , Mamo H B , Jelila Y D , Lemu H G
Published: November 2021

Fused deposition modeling (FDM) is the most prevalent thermoplastic additive manufacturing technology. Many input parameters and their settings have a significant impact on the quality and functionality of FDM parts produced. To enhance the quality of parts, it is critical to be able to predict surface roughness distribution in advance. The development of artificial neural network (ANN) models to forecast the impact of main FDM process factors on the part quality in terms of surface roughness while utilizing ABS (Acrylonitrile butadiene styrene) material is described in this work. Taguchi L9 orthogonal array was used to plan the experiments. Different printing input parameters such as layer thickness, orientation angle, and infill angle are used in the experiments. In terms of controllable input parameters, ANN is used to construct a predictive mathematical model. The effects of various printing settings on surface roughness were investigated using analysis of variance (ANOVA), main effect plots, and contour plots. Experiment findings and regression value are used to validate the models. The model has shown to be capable of adequately predicting responses within a maximum percentage error of 4.664 percent of arithmetic roughness average (Ra), which is a good agreement.
Review on fatigue life assessment methods for welded joints in orthotropic steel decks of long-span bridges
Authors: Villoria B , Siriwardane S C , Lemu H G
Published: November 2021

Orthotropic Steel Decks have been used in long-span bridges for several decades because of their high capacity to weight ratio. However, many fatigue related issues have been reported. This paper provides an overview of the main existing fatigue prediction models and discusses their relevance for the fatigue life assessment of Orthotropic Steel Bridge Decks (OSBDs). Several case studies have proven the importance of considering the combined effect of wind and traffic loadings to estimate the fatigue life of long-span bridges. The importance of incorporating welding residual stresses is also well documented while it is often disregarded in design practices. Reliability-based fatigue assessment methods make it possible to quantify how the sources of uncertainty related to loading conditions, welding residual stresses or fabrication defects can affect the fatigue reliability of OSBDs. Monte Carlo simulations are often used to perform probabilistic analyses, but machine-learning algorithms are very promising and computationally efficient. The shortcomings of the Palmgren-Miner rule are discussed and the need for alternative damage accumulation indexes is clear. A number of conclusions are drawn from the analysis of fatigue tests conducted on OSBDs.
Effect of SiO2 and SiO2/TiO2 hybrid nanoparticles on cementitious materials
Authors: Nori J , Kakay S , Belayneh M
Published: November 2021

In this paper, we report the effect of SiO2 nanoparticle solution on the properties of the neat industry and environmental cements. Moreover, the hybrid SiO2/TiO2 nanoparticles solution impact on the Portland G-class cement. Both destructive and non-destructive tests were used to characterize the properties of the slurries and the cement plugs. Results indicate that the optimum concentration of the nanoparticles improved the elastic, energy absorption, rheological, heat development, and the mechanical load carrying capacity of the cements. The selected optimal nanoparticles concentrations results showed that

• the addition of 0.56 % SiO2 by weight of cement (bwoc) increased the uniaxial compressive strength (UCS) of the neat industry cement by 16.7%.

• the 0.13% SiO2 bwoc increased the UCS of the neat environmental cement by 50.2%.

• the blending of 0.264 %SiO2/0.044% TiO2 bwoc increased the UCS of neat G-class cement by 8.5%. However, by changing the curing temperature and pressure, different results can be achieved.
Power supply and control systems for subsea production complexes in Arctic offshore fields
Authors: Kharchenko Yu A , Krotov K N
Published: November 2021

The subsea type of arrangement is no alternative for remote deep-sea oil and gas fields of the Arctic shelf. One of the main factors determining the level of reliability of year-round production of hydrocarbons using subsea production complexes is the availability of effective control and power supply systems. In this article the current state of subsea production complexes is studied, possible ways to develop power supply and control systems are analyzed in order to increase their efficiency and reliability when used in deep-water remote fields of the Arctic shelf.
Requirements for radar navigation aids for operational safety of autonomous navigation of facilities of the Arctic oil and gas complex
Authors: Golov N A , Ermakov A I , Presnyakov S V , Usachev V A
Published: November 2021

An analysis of the requirements for radar systems for autonomous sea vessels operating in the Arctic regions shows that to ensure the safety of transport and oil and gas facilities, it is necessary to evolution to radar systems with characteristics that significantly exceed the existing classification requirements. The application of ultra-wideband and ultra-short-pulse radars, including those based on the principles of microwave photonics, which will provide a radio-imaging mode and decimetre levels of accuracy when measuring coordinates, as well as observation of small objects, ice conditions and detection of oil spills, is proposed. The use of such radar facilities to ensure high-precision navigation will make it possible to start solving the problem of creating autonomous vessels, provided that the safety of logistics operations in the oil and gas complex is ensured.