bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Flow Characteristics inside Francis Turbine Draft Tube with Adjustable Guide Vanes
Authors: Joy Jesline , Raisee Mehrdad , Cervantes Michel J.
Published: June 2021

Numerical investigation was performed on a semi-model (one stay vane, two guide vanes, one runner passage inclusive of one main and one splitter blade, and the draft tube) of a high-head Francis turbine model with adjustable guide vanes in the draft tube. The motive of the present study is to investigate the possibility to mitigate the rotating vortex rope (RVR) formed at part load operating condition. Each guide vane in the draft tube consists of two hydrofoils. The upper hydrofoil is adjustable according to the flow angles leaving the runner. The lower hydrofoil is stationary and corresponds to the flow angle at best efficiency point (BEP).The factors considered while designing these guide vanes were a) number of guide vanes, b) chord length, c) span and d) position in the draft tube. The preliminary results indicate that the RVR pressure amplitude was suppressed by 97% compared to the reference model with no guide vanes at part load (PL) operating condition. An 8.7% increment in the draft tube pressure recovery was obtained which indicates that implementation of the guide vanes in the draft tube could positively impact the turbine efficiency beside the mitigation of the pressure pulsations at PL operation.
Particle image velocimetry measurements in the vaneless space of a model Francis turbine under steady state operation
Authors: Sagmo K F , Mærlie A , Storli P T
Published: June 2021

Two-dimensional, two component particle image velocimetry (PIV) measurements of the guide-vane wake and vaneless space for a high head Francis model turbine are presented. Measurements have been carried out with a fixed head and rotational speed for a set of guide-vane openings representative of part load, high load and best efficiency operating points. The measured trajectory and strength of the guide vane wake for the different operating points is discussed in conjunction with the periodic velocity oscillations. It is hoped that the present measurements will aid in further analysis as well as provide an additional set of data for validation of numerical analyses.
Experimental study on load rejection process of a model tubular turbine
Authors: Zhou Daqing , Chen Huixiang , Kan Kan , Yu An , Binama Maxime , Chen Yanan
Published: June 2021

To obtain the dynamic parameters variation characteristics of a model tubular turbine during the load rejection process, a model test method was designed and carried out in this paper. Firstly, the model test system, the test method and the model tubular turbine parameters were introduced. Then, the experiments of different schemes were performed and the results were analyzed. Evidently, the closing rules of guide vanes and runner blades have influence on the quality of transient process. When the guide vanes undergo linear needle closure law, the effect of prolonging the blade closing time on reducing the maximum speed appreciation and the maximum reverse water thrust is obvious, and when the guide vanes is closed in two stages, the longer the blade closing time, the lower the maximum reverse hydraulic thrust value. With the same closing law, the segmental closure law with guide blade first fast and then slow is more obvious than the linear needle closing law in reducing the maximum reverse water thrust, and the selection of closure segment point of guide vanes has a certain effect on the appreciation of the maximum rotating speed. Thus, the model test method could be used in transient operation improvement at hydropower plants.
60188 The coupled dynamic analysis of hydroelectric unit and powerhouse considering the bolt connection characteristics
Authors: Ma ZY , Chen H Y , Zhang H Z
Published: June 2021

As the increasing of the capacity and water head of the hydropower stations, the hydroelectric unit’s vibration and its induced powerhouse vibrations become a critical problem. The system of hydraulic-mechanical-electric-structural is coupled and with strong non-linear characteristics. The frame and head cover are all connected with the powerhouse pier via high-strength bolt. The paper is concentrated on the dynamic coupling mechanism and simulation model considering the bolt’s connection and load transmission characteristics. With the theory analysis and numerical simulation, the connection and transmission behaviour of the high-strength bolt would be studied and a more accurate and simple mechanical expression would be derived. The connection sliding law and dynamics modelling method of bolts are discussed. Based on the displacement-load curve of single lap and single bolt analysis it is concluded that the increasing preloading will improve the tangential bearing capacity of the bolted joint connection. Then the FEM coupling model of the lower bracket and powerhouse is established with the virtual medium method. Based on the free-vibration and dynamic response analysis the effects of the loosening of the bolt on the static stiffness of the coupling structure are discussed. The von-Mises stress’s increasing due to some of the bolt’s loosening would result to the material fatigue damage. Finally five preloading schemes of the bolts are discussed and the simulation results show that the preloading force has a greater lateral impact on the structure than on the longitudinal direction. The preloading force improves the coupling structure’s stiffness and reduces the vibration amplitude of the frame. As for the preloading force, when it is small the connection effect is not strong enough and the vibration level may be higher, so the actual preloading state should be exactly simulated. When the bolt preloading reaches 60-70% of the material yield strength, the rigid connection can be directly used in the modelling for the convenience of calculation.
Stereo-PIV study of unsteady flow in a laboratory air hydro turbine model over a wide range of operating regimes
Authors: Litvinov I V , Sharaborin D K , Gorelikov E U , Suslov D A , Shtork S I
Published: June 2021

Swirl flow with the formation of a precessing vortex core (PVC) in a hydro turbine draft tube model was studied using Stereo-PIV and four acoustic sensors. Experiments were performed on an aerodynamic setup in a wide range of operating conditions of the hydro turbine. Using a spatial Fourier decomposition of pressure pulsation data obtained from four acoustic sensors, a PVC was observed for part-load operating regimes (0.3-0.7Qc
). Mean flow features were shown for the range of operating regimes from a deep part-load regime (0.3Qc
) to an overload regime (1.5Qc
). Based on phase-averaged velocity distributions, the PVC spatial structure was identified for maximum pressure pulsations on the cone walls of the draft tube.
Numerical study on Unstable Hydraulic Factors of Kaplan turbine with semi-spiral case at large flow rate conditions
Authors: Zhao Yaping , Li Zhihua , Dang Mengfan , Feng Jianjun
Published: June 2021

The operation of semi-spiral case Kaplan turbines at large flow rate conditions is restricted by factors such as severe cavitation and severe vibration, which limit the maximum output of the unit. In order to explore the main hydraulic factors that cause the poor operating stability of the unit at large flow rate conditions, and provide a reference for the operation and design of the turbine, the numerical simulation method is adopted to conduct the performance study of an semi-spiral case Kaplan turbine at different operating conditions, by comparing and analysing the results at the optimal conditions and large flow rate conditions, the unstable hydraulic factors at large flow rate conditions is obtained. The research results show that: at large flow rate conditions, the uneven flow distribution in the semi-spiral case cause vortices between the guide vanes, lead to the large fluctuations of blade torque, and generate unstable back-flow and vortices in the draft tube. These phenomena combined with the various gap flows in the runner, make the internal flow of the Kaplan turbine at large flow rate conditions deteriorate, cavitation increase, efficiency decrease, and cause severe vibration, thereby limiting the stable operation of Kaplan turbine at large flow rate conditions.
Investigation of water column separation induced by pressure pulsation based on critical cavitation rate model
Authors: Yang J B , Yang J D , Guo W C , Luo J J , Fu G F
Published: June 2021

Significant pressure fluctuation may exists at the inlet of the draft pipe during load shedding of water pump and turbine sets. When the tail-water level is low, the minimum water hammer pressure at the inlet of the draft pipe set is higher than evaporation pressure; however, the overall pressure after superposition with pulsating pressure may reach the evaporation pressure in an instant. In these cases, it is unknown if a cavity is formed or water column separation is induced. It is also unknown how frequency and amplitude of the pulsating pressure affect the formation of cavity or water column separation. However, in terms of the physical formation of water column separation, liquid pressure reaching evaporation pressure is only the necessary condition of water column separation rather than a sufficient condition because the growth and aggregation of cavitations take time. In addition, water column separation could be induced only when the cavitation rate in the water reaches a specific value and gas-liquid relative motion occurs. In this study, based on the uniform cavitation distribution model, the critical of flow velocity gradients are calculated both in front and at the back of the section and are the sufficient condition of water column separation. This study uses the criterion of when the ratio of the vaporous cavitation volume to the volume of the pipe segment with a length of Δx exceeds a critical cavitation rate for classifying water column separation segments and non-water column separation segments. In water column separation segments, a concentrated vaporous cavitation model is used for calculation; however, dynamic meshes should be applied for tracking the change of vaporous cavitations. In the non-water column separation segments, the vaporous cavitation volume can be calculated according to the continuity equation but is converted into a cavitation rate in the pipe segment and substituted into gas-liquid two-phase equation to calculate wave velocity. Next, a case study was performed on a pipe-valve system. By taking into account the pulsating pressures with different frequencies and amplitudes on the downstream side in the valve closing process, water column separation and merging processes were analyzed and the change in flows, cavitation volumes and pressures on various sections and their laws during the transient process were concluded.
Accurate and efficient analysis of dynamic runner stresses considering hydrodynamic damping effects
Authors: Hübner Björn , Koutnik Jiri
Published: June 2021

Safe and reliable dynamic designs of Francis and pump turbine runners require an accurate and efficient prediction of the dynamic response during operation including dynamic stresses. If resonance phenomena cause significant dynamic amplifications, response amplitudes strongly depend on damping effects, and numerical simulations have to include realistic damping behavior. For submerged components like turbine runners, hydrodynamic (flow-induced) damping and hydro-acoustic radiation are much greater than structural or material damping, but cannot be assessed sufficiently accurate by simple assumptions. Therefore, a newly developed fluid-structure interaction (FSI) methodology is presented which offers accurate and efficient harmonic response analyses of submerged structures not only accounting for added-mass effects but also for flow-induced damping and acoustic radiation. The acoustic FSI approach, widely used to consider added-mass effects, is enhanced by convective terms to include fluid forces caused by the deflection of the mean flow due to structural motion. Only a stationary flow solution, obtained from standard computational fluid dynamics analyses, is required as additional input. The linearized second-order system with non-proportional damping matrix is solved in frequency domain using a Krylov subspace based model order reduction technique. The methodology is validated using experimental damping data from an elastic hydrofoil in a cavitation tunnel. A first application to a prototype Francis runner, being excited close to resonance by rotor-stator interaction, reveals a significant influence of the operating condition on hydrodynamic damping and dynamic stresses. The numerical results for both part load and full load agree very well with measured prototype strains. Meanwhile, the automated methodology is applied as a standard tool within the hydro-mechanical runner design process ensuring dynamically safe and reliable runner designs.
Numerical analysis of an initial design of a counter-rotating pump-turbine
Authors: Fahlbeck Jonathan , Nilsson Håkan , Salehi Saeed , Zangeneh Mehrdad , Joseph Melvin
Published: June 2021

Renewable sources of energy are on the rise and will continue to increase the coming decades [1]. A common problem with the renewable energy sources is that they rely on effects which cannot be controlled, for instance the strength of the wind or the intensity of the sunlight. The ALPHEUS Horizon 2020 EU project has the aim to develop a low-head hydraulic pump-turbine which can work as a grid stabilising unit. This work presents numerical results of an initial hub-driven counter-rotating pump-turbine design within ALPHEUS. Computational fluid dynamics simulations are carried out in both prototype and model scale, for pump and turbine modes, and under steady-state and unsteady conditions. The results indicate that the initial design have a hydraulic efficiency of roughly 90 % in both modes and for a wide range of operating conditions. The unsteady simulations reveal a complex flow pattern downstream the two runners and frequency analysis show that the dominating pressure pulsations originates from the rotor dynamics. Given the promising high efficiency, this initial design makes an ideal platform to continue the work to optimise efficiency and transient operations further.
Evaluation of guide vanes effect over runner Francis turbine sediment erosion using a quasi-two dimensional approach
Authors: Quishpe L M , Valencia E A , Hidalgo V H , Zambrano O I , Cando E H
Published: June 2021

Francis turbines are widely used in hydroelectric power plants all over the world, Ecuador is not an exception to this trend. Hence, Francis turbine design and assessment have taken importance in order to provide in-house design methods to enhance their performance in the region. The volcanic nature of the region facilitates sediment formation, which produces drastic erosion problems in many Francis turbines. Since guide vanes set the inlet flow velocity of the runner and erosion is related with the velocity distribution through this latter, this work evaluates guide vane profiles using a quasi-two dimensional approach to assess the impact of guide vane design on erosion rate. For this aim, parametric analysis and a mean line analysis are employed for the conceptual geometrical design, which then is coupled with a panel vortex model to assess the two dimensional hydro profiles for the guide vanes. Thus, the velocity triangles at entry and exit of the guide vane-runner setup can be related to the erosion rate within the runner. At this stage the calculations were carried out at the BEP and for the validation experimental data from the San Francisco hydroelectric power plant was used. The results show how the model developed captures main performance trends and enables the correlation of erosion with the geometrical features of the guide vanes. The method used is accurate enough for preliminary design and its low computational resources with versatility make it suitable for optimization routines for erosion proof designs.
Proper orthogonal decomposition of turbulent swirling flow of a draft tube at part load
Authors: Kumar S , Khullar S , Cervantes M J , Gandhi B K
Published: June 2021

A large scale vortical structure, i.e., rotating vortex rope (RVR), generally forms at part load (PL) operation of a reaction turbine due to the combined effect of swirling flow at the runner outlet and the adverse pressure gradient in the draft tube. Even with the data analysis through advanced measurement techniques like Laser Doppler velocimetry (LDV) and Particle Image Velocimetry (PIV), the information available about the flow instabilities developed due to RVR is still incomplete. This paper presents an application of the proper orthogonal decomposition (POD) method to analyze the flow field inside the draft tube cone at PL operation of a high-head model Francis turbine. The POD analysis is performed on 250 PIV snapshots containing the axial and radial velocities. The results show that the first eight modes contain more than 95% of the total kinetic energy (KE) of the flow field and are associated with the organized motion of the flow. The first mode contains more than 50% of the total energy, and the axial velocity profile reconstructed with the first mode is identical to the mean axial velocity flow field. The maximum dissipation of the turbulent kinetic energy (TKE) occurs through unorganized motion.
Performance analysis of a new type of space guide vane for T-type hydraulic turbine
Authors: Li Yanpin , Jiang Yuxuan , Zhang Zichao , Chen Dexin
Published: June 2021

At present, the flow passage of multistage T-type (designed according to the theory of hydraulic prime mover) hydraulic turbine directly adopts pump type interstage guide vane, which has poor matching degree and low performance. In order to improve the performance of T-type hydraulic turbine, this paper takes a two stage T-type hydraulic turbine as the research object, designs a new type of space guide vane as its interstage guide vane according to the theory of hydraulic prime mover, selects the thickness of the baffle, the diameter of outer edge of guide vane, the outlet angle of positive guide vane, and the number of guide vanes to formulate L9 (34) orthogonal test, and applies CFD numerical calculation to 9 Through the range analysis method, the primary and secondary factors affecting the external characteristics of T-type hydraulic turbine are found out. The results show that the outer diameter of the guide vane has the greatest influence on the performance of the new type of space guide vane. In order to further study the influence of guide vane outer diameter on turbine performance, four different guide vane outer diameter of 700mm, 750mm, 800mm and 850mm are selected to analyze its influence on the outer characteristics and internal flow field of the whole T-type hydraulic turbine. It is found that with the increase of the outer diameter of the guide vane, the efficiency of the hydraulic turbine increases first and then decreases, the head decreases first and then increases, and there is an optimal value of the outer diameter of the guide vane. As the diameter of the outer edge increases, the flow path of the positive guide vane and the negative guide vane becomes longer, the flow velocity decreases, the flow control ability decreases, the turbulent kinetic energy increases, the area of the high pressure area of the negative guide vane decreases, and the flow pattern becomes worse.
Analysis and visualization of progressive erosion in Pelton buckets
Authors: Rai Anant Kumar , Kumar Arun , Yexiang Xiao , Guo Bao , Staubli Thomas , Arora Naman
Published: June 2021

Hydropower plants operating in fragile mountainous regions face severe hydro-abrasive erosion of hydraulic components, which results in drop in efficiency, frequent interruptions in power generation and downtime for repair/replacement. Due to high flow velocity in components like nozzles and buckets, a Pelton turbine is highly susceptible to erosion. The effect of erosion is observed as cumulative loss of material and study of its gradual progress required frequent measurement. In this study, in-situ images of Pelton buckets were captured throughout a sediment period at a hydropower plant located in Himalayan region, India and analysed for characteristics of progressive erosion damages. A multi-layered paint method was used to visualize the initiation of erosion in different parts of bucket. Removal of colours due to erosion provided the information on erosion initiation and various erosion zones in bucket. The erosion of outer side of bucket was analysed with single layer paint removal and images from past records of the plant. Further, the effect of initial condition of a bucket on cumulative erosion after a sediment season is also presented for both coated and uncoated buckets.

The in-situ photographs during the silted water period suggested that the outlet portion inside the bucket faces significant erosion. The technique of image capturing throughout sediment season was successful in obtaining progressive erosion. Such method with a reference scale in the image is an effective method to quantify erosion like width increase of the splitter more frequently. The paint in the buckets was found capable of providing information on erosion initiation and erosion zones inside Pelton buckets. The erosion characteristics of outer side of the bucket confirms the presence of a Coanda effect. This study will facilitate turbine designers and manufacturers in better coating and/or surface treatment to specific zones of bucket to minimize efficiency loss due to distorted profile of the bucket, as more prone surfaces can be coated with thicker coatings to protect it longer from erosion.
Experimental investigation of sediment erosion of turbine steel used in Bhilangana-III power-plant
Authors: Sharma Shubham , Gandhi Bhupendra K
Published: June 2021

Turbines located in the geographical regions of Africa, Himalayan, South-East Europe and South America are subjected to erosion due to sediments flowing with water. The extent of damage due to erosion depends on the material property and the impinging condition of particles. In this work, experiments have been performed in a high speed pot tester on the steel used for Francis turbine of Bhilangana-III power-plant. The erosion rate is determined by mass loss of the specimens rotating inside the pot. The erosive wear behavior of turbine steel is evaluated at high velocities of 27 m/s and 32 m/s by varying the orientation angle from 15 to 90 degrees. The mean particle size and sediment concentration are selected as 300 µm and 3000 ppm, respectively. The erosion rate of turbine steel is increased with impact angle upto 30 degree and then decreased with a further increase in impact angle till 90 degree. The effect of variation of particle impingement velocity on erosion rate behavior of turbine steel is determined for the velocity range of 13-32 m/s. The erosion rate increased with increase in the velocity. Further, the mechanism of erosion with the variation in velocity is analyzed at different impact angles using SEM micrographs of worn out samples.
Comprehensive stay vane vibration analysis by means of numerical and experimental approaches
Authors: Sampaio Ricardo , Neto Alexandre D’Agostini , de Camargo Gissoni Humberto , Filho Rubens Marras , de Araújo Pedro Gayer , da Silva Assi Gustavo Roque , Cicolin Murilo Marangon
Published: June 2021

Vortex-induced vibration is the most common phenomenon associated with the development of cracks in hydraulic turbine stay vanes and although the trailing edge modification is an usual and well-known solution, its empirical application may not lead to the complete elimination of the cracks. During Ilha Solteira hydropower plant history several modifications were implemented, but only the one applied to vane 24 was successful in avoiding cracks recurrence.

To better understand this phenomenon, a 2D transient Computational Fluid Dynamics (CFD) simulation was developed incorporating the fluid-structure interaction effect by allowing the simulated vane to move perpendicularly to the flow. Additionally, field measurements and laboratory experimental results were used to calibrate the numerical model. A comparison of the results obtained by CFD with the ones measured in the laboratory revealed differences smaller than 1% for the peak displacement amplitude.

When applied to the prototype scale, the simulation was able to capture the lock-in effect in a frequency around the one measured at site which corresponds to the first bending mode of the vanes. A geometrical modification was developed, tested numerically and implemented at site. Later strain-gauge measurements confirmed that the modified stay vanes were no longer being excited in their first mode, resulting in a 90% reduction of the oscillating stress amplitude.
On the Comparison of Hydroelectric Runner Fatigue Failure Risk Based on Site Measurements
Authors: Morin Olivier , Thibault Denis , Gagnon Martin
Published: June 2021

The fatigue reliability of a turbine runner is closely related to its dynamic behavior. Over the past few years, Hydro-Québec has performed measurement campaigns on many of its turbine runners. These measurements led to the evaluation of the fatigue risk level of each runner in various operating conditions, which allows operating conditions with a higher risk of crack propagation to be avoided. This paper presents the results for turbine dynamic behavior assessed in steady-state conditions. Stress levels at strain gauge locations are used to evaluate the risk of fatigue cracking based on the Kitagawa-Takahashi diagram. Results show a good correlation between the calculated risk of cracking and real cases of cracks found in runners. Furthermore, the results comparison highlights a apparent tendency for recent designs to be more prone to cracking at speed-no-load operating condition than older designs. The paper gives an overview of the methodology used and discusses the conclusions derived from the sample of turbine runners available for this study.
A new real time hydraulic test platform dedicated to Ancillary Services
Authors: Mesnage Hugo , Guillaume Renaud , Bacha Seddik , Bayle Simon , Nichele Sylvain
Published: June 2021

Characterization of Hydraulic turbines, storage pumps and pump-turbines is a well-known process formalized in the IEC60193 standard. Test platforms ensure the acceptance of hydraulic design with respect to hydraulic transpositions such as efficiency, range of operation, cavitation, stability etc. These test platforms only focuses on the static operation of a turbine. The HydroPHIL platform - which stands for Power Hardware In the Loop for Hydro-electrical conversion - focuses on studying transients operations of Pump Storage Plants. It includes a fully operational scale model of a hydraulic units from water to wire. The scaled model interacts with a real time grid emulator and a real time penstock emulator. The test platform allows the simulation of technologies in relevant environment related to three main topics of investigation: a) system behavior study, whether it is solicited by the grid (frequency or voltage dips, etc.) or the piping system (water hammer, etc.) b) new conversion technologies with real electrical components (such as variable speed PSP), and c) development of new control strategies to improve provision of ancillary services and other flexibility services. This paper presents the platform architecture and features.
Transfer learning for isolated cylinder vibration induced by vortex shedding
Authors: Miao Yang , Jiang Yuncheng , Zhang Xiaolu , Li Kun
Published: June 2021

Transfer learning study on vortex-induced vibration of circular and bending cylinders in laminar flows. Vortex-induced vibrations of circular and bending cylinders have been detected by varying flowrate in rectangle cylinder. The vibration date in different position of the cylinders are acquired by LMS and image information obtained. The dynamic characteristics of vortex shedding are analyzed by the cylinder vibration and flow rate signal. The experimental data of the circular cylinder vibration is used as auxiliary data set and a few data of the bending cylinder vibration as target data set. Both of auxiliary and target data sets compose the training set which is trained by TrAdaboost based on weight iteration adjustment. The result compared with another experimental data of bending cylinder shows that the transfer learning algorithm has a reasonable accuracy.
Demand and supply of shallot in North Sumatera Province
Authors: Taufiq M , Rahmanta  , Ayu S F
Published: June 2021

Shallots have a fluctuating demand therefore this is not balanced by a continuous supply. The purpose of this study was to see what factors influence the demand and supply of shallots in north Sumatera province. The method of analysis used is a simultaneous equation approach using data from 1989-2018 and processed with the help of software programs. 10. The results show that the price shallots, population together had a significant effect on the demand of shallots in north Sumatera province. The price of shallots, harvested area and fertilizer prices together had effect on the supply of shallots north Sumatera. Per capita income and fertilizer prices together have effect on the price of shallots in north Sumatera province.
Analysis of factors affecting the growth of agriculture sector in North Sumatra
Authors: Hasibuan M , Rahmanta  , Ayu S F
Published: June 2021

Agriculture sector is one of the supporting economic sectors in North Sumatra Province. In 2018, the agricultural sector (food crops, plantation, forestry, livestock, and fisheries) was the sector that contributed the largest added value to the Gross Regional Domestic Product in North Sumatera Province, namely 21.4 percent, followed by the manufacturing sector at 20.29 percent. Therefore, it is necessary to conduct research the factors that influence the growth of the agriculture sectors in North Sumatera. The secondary data from the Central Statistics Agency of North Sumatra Province are used to obtain the data since 1985-2018. The analytical method used was multiple linear regressions. The results this paper that labour and agricultural imports had a positive and insignificant effect on the growth of agricultural sector. Meanwhile, land area, exports, and an investment have a positive and significant effect on the growth of agricultural sector.
Analytical landslides prone area by using Sentinel-2 Satellite Imagery and geological data in Google Earth Engine (a case study of Cinomati Street, Bantul Regency, Daerah Istimewa Yogyakarta Province, Indonesia)
Authors: Prasetya H N E , Aditama T , Sastrawiguna G I , Rizqi A F , Zamroni A
Published: June 2021

The incidence of landslides and the fact that a large number of people live in areas vulnerable to landslides lead to a high death toll in Java Island, Indonesia – more than 1,112 people in the period 1999 to 2005. The study site has an area of 55.56 hectares, along Cinomati Street, Dlingo, and Pleret Sub District, Bantul District, Daerah Istimewa Yogyakarta Province, Indonesia. The methods that use in this study are, Sentinel-2 Imagenery and Geological data. The purpose of this study is to determine the landslides prone area in the study site. The methods used in this study are Sentinel-2 Satellite Imagery and geological data. Along the Cinomati road based on geological data, it has a weak area that has the potential for landslides from the continuation of the Opak fault and rock formation boundaries. Landslide area are locations with complex geological conditions and sparse vegetation. In other rare vegetation besides the location of landslides, it also needs to be aware of other potential landslides, because this research is limited to sentinel images with a density of 10m2.
Utilization of charcoal rambutan (Nephelium Sp.) adsorbent to remove dissolved copper (II) by natural batch operation
Authors: Haryanto B , Manik K , Lumbangaol A K , Turmuzi M , Misran E
Published: June 2021

The adsorption ability of rambutan charcoal with the size 100/200 mesh in absorbing dissolved 70 ppm copper metal ions (Cu(II)) at pH 4.5 have evaluated. The adsorption kinetics of rambutan charcoal carried out by natural batch operation. The optimum contact time was 120 minutes with the best removal percentage was obtained 43.84%. The adsorption interaction of copper metal ions on the rambutan charcoal surface has analysed by using SEM-EDX. The kinetic model of the pseudo second-order was applied with interaction with R2 = 0.9816. The result was identified that adsorption occurred chemically. The diffusion kinetic model has indicated the diffusion down to the inter-particle surface of the adsorbent with the value of R2 = 0.8863.
Analysis of beef price determinants in North Sumatera
Authors: Lindawati L , Emalisa  , Situmorang S
Published: June 2021

Beef Prices in North Sumatera show a continuous increase. This research was conducted by collecting secondary data in North Sumatera in 2020. The purpose of this research was to find the factors that influenced the increase in the price of the beef. The analysis method to explain the factors that influence the beef prices in North Sumatera was Multiple Linear Regression analysis. There was no violation of classical assumptions such as autocorrelation, heteroscedasticity and multicollinearity so it can be said that the estimation of the regression model was unbiased. The results showed that there were three factors that had a positive and significant effect on the 5% error rate on the beef prices in North Sumatera, namely the world beef prices, Rupiah exchange rate against the Dollar and beef imports in North Sumatera. The beef production in North Sumatera affected on the beef prices in North Sumatera at an error level of 10%. The consumption of beef did not have a significant effect on the beef prices in North Sumatera.
Performance of agricultural machinery services business in Tojo Una-Una District Central Sulawesi
Authors: Amalia A F , Rahayu H S P , Syafruddin  , Suwitra I K
Published: June 2021

Advanced technology has entered the agricultural sector in an effort to streamline the agricultural production. Mechanization, one of advanced technology has contribution to increase productivity and resource’s efficiency in agriculture. However, there is a need government’s intervention to accelerate it. One of mechanization program by government is Agricultural Machinery Services Business (UPJA) which applied in farmer group level in Indonesia. The study aims to know the financial and work performance of UPJA in Tojo Una-Una Central Sulawesi especially for four wheel tractor with 85 House Power (HP) and 95 House Power (HP). The data were collected purposively from the UPJA program receiver and related stakeholder. Financial and work performance analyses were used to value the UPJA performance. The results show that UPJA business in farmer group level for both 85 HP and 95 HP tractor power were economically feasible with RC ratio of 1.27 and 1.15 consecutively. Tractor 95 House Power (HP) was more efficient compared to 85 House Power in land efficiency management with values 62% and 54%. The theoretical field capacity (Kt) tractor 85 HP was the same with tractor 95 HP about 0.403 ha/hour, while the effective field capacity (Ke) of tractor 95 HP was higher compared to 85 HP.
The effect of airflow distribution on temperature, liquid smoke, rice husk ash and plastic oil yield using prototype systems of pyrolysis equipment organic-inorganic waste
Authors: Sigalingging R , Susanto E , Panggabean S , Muda I
Published: June 2021

Airflow influences the pyrolysis process. This study was carried out on air distribution flow in the integrated pyrolysis tool of plastic waste and rice husks with added pipeline inside the rice husk’s reactor furnace and without added it. A total of 10 kg of rice husk, 3 kilograms of plastic burlap, and 25 m s-1 initial air velocity from the blower were used. The results showed that the addition of 1-inch diameter pipelines with 18 holes with a 2.5 mm diameter affected the yield of rice husk oil, husk ash colour (white, grey and black) and the temperature at T4 (16 cm from the base) and T7 (54 cm from the base). In contrast, the other temperature was not a significant effect. Also, the yield of plastic oil produced was not impacted considerably. The yield of ash and rice husk oil (RHO) without using an airflow pipe was higher than using an airflow pipe, but the resulting plastic oil (PO) was lower.
The simulation of landuse change scenarios on Bedagai Sub Watershed health condition
Authors: Nasution D L S , Susanto E , Ichwan N
Published: June 2021

Erosion is one of three indicators that showed the health condition of watershed. The most important human intervention factor that influence condition of erosion is landuse. This study aimed to calculate the erosion value at existing condition on Bedagai Sub Watershed and optimizing watershed management by simulating some scenarios based on addition of forest land cover index to analyse its effects on erosion value. The calculation of erosion using USLE Method and ArcGIS 10.3 application. There are three scenarios simulated using Arc GIS 10.3 which is in each scenario the addition of forest land cover is about 5%. The forest land cover in existing condition is about 4%, in the scenario 1 is about 10% landcover index, scenario 2 is about 15% forest landcover index, and scenario 3 is about 20% forest landcover index. The result shown in existing condition, the erosion value was 209.74 ton/ha/year which classified as high hazard level. The simulation of three scenarios shown the erosion value by applying scenario 1 was 169.97 ton/ha/year, scenario 2 was126.52, and scenario 3 was 95.97 which is in medium hazard level.
Landuse changes simulation for erosion control in the Asahan Hulu Sub Watershed
Authors: Pasaribu S , Nasution D L S
Published: June 2021

Landuse changes that don’t follow the principles of land conservation are susceptible to erosion, sedimentation, and flooding. This study aims to determine the most optimal land use scenario in order to reduce the rate of erosion and analyse the effect of land use change on erosion. This research was conducted by collecting rainfall data, soil type maps, slope maps, and land use maps then overlaid using arc GIS and then calculating the erosion value. The simulation is done by reducing production land cover index and increasing forest landcover index. The results showed that the annual erosion value in existing condition was 111.67 tonnes / ha / year which is moderate erosion hazard class. The amount of increasing forest land cover area in scenario I is about 2881.80 ha, scenario II is about 5266.95 ha, and scenario III is about 7652.12 ha. The reduced erosion in each scenario of landuse change is 103.489 tonnes/ ha / year, in scenario 1, 93.642 tonnes / ha / year at scenario II, and 87.358 tonnes / ha / yr at scenario III.
Effect of Gelugur acid extract (Garcinia atroviridis) on the physical quality of culled chicken meat at different shelf life
Authors: Patriani P , Wahyuni T H , Sari T V
Published: June 2021

This study aims to find out the interaction between the percentage of Garcinia atroviridis extract and the shelf life of the physical quality culled chicken meats. This study used a complete randomized design of factorial patterns. The first factor is the concentration of Garcinia atroviridis extracts (P0:0%, P1:3%, P2:6% and P3:9%). The second factor is the shelf life at (T1:24 hours and T2:48 hours). The data was analysed using a nova and if there was a noticeable difference will be continued using Duncan tests. The results showed that there was an interaction (P<0.01) between the increase of Garcinia atroviridis P1, P2, and P3 in the shelf life of T1 and T2 against pH, cooking loss, meat moisture content. However, there is no interaction (P >0.05) between Garcinia atroviridis in shelf life against the drip loss of meat. The higher Garcinia atroviridis extract will lead to decreased pH value, lower cooking loss value, and increase meat moisture content. The results showed the physical quality of culled chicken meat was still in the normal range. The use of Garcinia atroviridis extract 3% is recommended to improve the physical quality of culled chicken meat at a shelf life of 24 to 48 hours.
Protein digestibility and metabolizable energy of palm kernel cake fermented by Starbio on chicken
Authors: Prayogi G , Tafsin M , Wahyuni T H
Published: June 2021

The research is to find out the level starbio in palm kernel cake (PKC) on the energy and protein use on chicks. The chemical analysis was done in Quality and Certification Feed Laboratory in Bekasi, West Java. The experiment composed by five treatments i.e. dose of starbio (g/kg PKC) with level: 0%;0,25%; 0,5%; 0,75%; and 1%; for treatments PO;P1:P2:P3; and P4, respectively. The variables were observed composed of apparent metabolizable energy (AME), protein digestibility, and nitrogen retention. The starbio had significantly (P<0,01) effect on protein utilization and AME of PKC for chicks. Increasing that nutrient utilization on chicken in line with of dose of Starbio. it is concluded that starbio can improve PKC quality as feed for chicks.
Improving productivity and competitiveness of Kepahiang robusta coffee through innovation and partnership
Authors: Dewi Y A , Hutahaean L , Rubiyo
Published: June 2021

Robusta coffee is a very strategic commodity in Kepahiang district, bengkulu province. This paper aims to (i) describe the overview, coffee quality and flavor, the financial feasibility of Kepahiang coffee farming, (ii) formulate technological innovations in increasing productivity, and (iii) formulate efforts to increase competitiveness. The paper was synthesized from literatures related robusta coffee, and it was conducted in 2019. All data were gathered from secondary data using documentation methods and the data from relevant literature were analyzed descriptively. Based on the synthesis, the productivity of Kepahiang robusta coffee is only around 774 kg/ha or still below its production potential. Kepahiang coffee was characterized as small beans with grade 5 and 6 while the total of flavor total was 80.50 - 85.50. Efforts to increase Kepahiang coffee productivity can be done through technological innovations such as the use of high yielding planting material, pest and disease control, pruning technology as well as postharvest and processing improvement. Increasing competitiveness can be done by developing partnerships that are designed through 4 (four) stages, namely phase 0, phase 1, phase 2 and phase 3. Technological innovation and partnership relationships are expected to increase productivity and competitiveness of Kepahiang robusta coffee.
Improvement of soybean yields using organic fertilizer enriched with microbes under dry land condition of Banten Province
Authors: Yuniarti S , Mulyaqin T , Hadiatry M C , Purba R
Published: June 2021

The objective of the present study was to determine the yield and growth of soybeans using organic fertilizers enriched with microbes under dryland conditions. The research was carried out in the Pandeglang Regency of Banten Province. A randomized block design was used using 4 treatments, and 6 replications. The treatments were fertilization, namely without fertilizer (control/P1); 3 ton/ha of chicken manure (P2); 3 ton/ha of chicken manure, and recommended inorganic fertilizer (P3); 1 ton/ha of organic fertilizer enriched with microbes, and recommended inorganic fertilizer (P4). The soybean variety used was the Anjasmoro variety. The parameters observed were the length of root, the height of plant, the nodules number, root weight at age 65 days after planting (DAP), the filled pods’ number, and the soybean yield. The research results showed that the treatment of organic fertilizer enriched with microbes (P4) gave a higher growth response based on the value of the height of the plant, the length of root, the number of nodules, and the number of filled pods, compared to other treatments. It increased soybean yield from 1.58 ton/ha up to 2.61 ton/ha.
Potential carbon storage of Indonesian mangroves
Authors: Maulana M I , Auliah N L , Onrizal
Published: June 2021

Even though it only covers 0.1% of the surface of the continent, mangrove forests recorded as carbon-rich forests on earth. Forest loss and degradation together, especially in the tropics contributes about 12% of the total annual anthropogenic CO2 emissions. Mangrove forests ecosystem have high carbon storage potential. The study results show that the ratio of carbon to area in mangrove ecosystems is almost 13 times greater than that of tropical rainforest ecosystems in Indonesia. This study has used published data recorded in Google Scholar and Science Direct. Indonesia’s mangroves, with a total area of 3.1 million ha, store a total carbon of 5.2 Gt. The average stand biomass or aboveground biomass is around 407.15 tons ha−1, storing carbon as much as 191.36 tons ha−1 which is equivalent to the potential for CO2 absorption (CO2e) by mangrove stands of 702.29 tons ha−1. Papua has the largest mangrove forest in Indonesia that has the potential for CO2e. Assessment of carbon storage in soil needs to be done in estimating the total carbon stored in mangrove ecosystems, given the large potential for stored carbon that plays a role in climate change mitigation.
Characteristics and classification of coastal peat in conservation forest at Labuhanbatu, Sumatera Utara, Indonesia
Authors: Sitohang E J , Sarifuddin  , Mukhlis
Published: June 2021

This study is a survey research that aims to characterize and classify coastal peat soils in the conservation forest located in Sidomulyo Village, Bilah Hilir Subdistrict, Labuhanbatu District. Soil analysis was carried out at the Research and Technology Laboratory of the Faculty of Agriculture, Universitas Sumatera Utara. The observations were carried out by drilling the peat soil using an Eijkelkamp drill with 3 depth layers of peat soil, then the morphology and chemical properties of the soil were observed and classified according to the Key to Soil Taxonomy, 2014. The results showed that the ash content in the surface layer was higher than the deeper layers, but pH, C-organic, EC and CEC were not much different at all layers. Based on soil taxonomic, peat in the study area is Hydric Haplohemist for sub group category.
Fertilizer effectiveness based on nutrient requirement from yield of green mustard (Brassica juncea L.)
Authors: Majid M I , Harahap E M , Sembiring M
Published: June 2021

Green mustard (Brassica juncea L.) is a vegetable that has a high economic value. The application of fertilizer was important to increase crop production. This study aims to calculate the nutrient requirement to get the optimal yield production. The method used survey methods (qualitative research) on June-July 2020. The conventional planting experiment design was 20 × 20 cm spacing/plant in 1 hectare. The percentage of N used the Kjeldahl method, whereas the P, K, and Mg using Spectrophotometry, and the data were analysed by Microsoft Excel, 2013. The variable observed i.e. wet weight (g), dry weight (g), Md dry basis (%), the percentage of N, P, K, and Mg, and total fertilizer needed for 10 ton/ha; 20 ton/ha; 30 ton/ha, and 40 ton/ha. The results were N 3.857 %; P 0.721 %; K 3.827 %; and Mg 0.366 %. Wherein, the average weight of wet green mustard was shown 91.014 g wherein the dry weight of 6.718 g. The Md (dry basis) was 12.54. The fertilizer complex recommendation to green mustard for optimal yield up to 40 ton/ha was 5.45 g/pot. In this case, a total of urea 2.46 g/pot, SP-36 0.57 g/pot, KCl 1.83 g/pot, and dolomite 0.58 g/pot.