bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement in accuracy of engine cycle simulations by using a turbocharger prediction model instead of measured efficiency map
Authors: Misono Y , Kuboyama T , Moriyoshi Y , Yamada T 
Published: May 2021

Abstract
In the downsizing concept, the turbocharger (T/C) is one of the key devices for improving thermal efficiency and exhaust emissions of internal combustion engines for automobiles. In order to maximize the supercharged engine performance, the size of the T/C applied for the given engine system has been optimized by using a 1-D engine cycle simulation. For this reason, T/C performance prediction model for engine cycle simulation is required to be accurate over a wide operating range. In the conventional T/C performance prediction model, the turbine performance was predicted by extrapolating from the efficiency map measured under steady flow. However, the accuracy of the extrapolation method is uncertain, and it has been pointed out that the prediction accuracy is low in the low load operations. In this study, a 1-D T/C model developed based on hydrodynamics and thermodynamics was used. Using the 1-D T/C model, a grid efficiency map over the entire operating range was calculated and the grid map was applied to 1-D engine cycle simulation. The accuracy of the T/C model was verified by comparing the experimentally measured efficiency under steady flow.
Analysis of Flow Models for Aerostatic Thrust Bearings with Porous Material
Authors: Schimpf A. , Gu Y. , Böhle M. 
Published: May 2021

Abstract
The numerical determination of static characteristics of bearings allows a cost-efficient and fast pre-design. In this study, two flow models for aerostatic thrust bearings with pressurized porous material are presented and analyzed. The models are based on the coupling of the Reynolds equation for lubricants (REL) and the determination of pressure drop through porous material by Darcy’s law. The simplified model is based on the assumption of a one-dimensional axial flow through porous media. The extended model considers the three-dimensional flow in the porous body. The analysis includes pressurized air from 4 to 9 bar(a) with nominal clearance of 5 to 60 µm. Commercial CFD software was used to verify the results. The extended model allows a more accurate prediction about the performance in the critical gap range. In total, the results show good agreement with CFD within a short computation time.
Experimental performance of a pump and the related vortices in a pump intake of a model pump station
Authors: Guo Miao , Zou Huijun , Chen Baoyu , Zuo Zhigang , Liu Shuhong 
Published: May 2021

Abstract
In order to quantitatively study the relationship between the performance of a pump and the related hydraulic phenomena in a pump intake of a model pump station, a model test was carried out in the present paper. The results show that when the dimensionless water level (water level/diameter of the pipeline: W/d) WL*≥5.46, the influence of the water level on the performance of the pump can be ignored, and the operation of the pump is stable. When WL*=5.15, the performance of the pump decreases deeply, the dimensionless flow rate (actual flow rate/reference flow rate under standard working condition) Q* can be as low as 0.79, and the pump becomes noisy. Finally, when WL *<5.15, although the impeller is still rotating and the input power is unchanged, the pump no longer pumps water.
Study on S-shape instabilities and pressure pulsations in reversible pump-turbines: Conflictive mechanisms behind a varying rotor-stator distance and development of a new guide vane design for improving transient behavior during turbine start-up and in case of load-rejection
Authors: Lenarcic M. , Gehrer A. 
Published: May 2021

Abstract
Increasing demands towards a more flexible and reliable operation of backbone systems for electrical grid stability has been leading to an upsurge of pumped-storage in the last years. As technological requirements concerning reversible pump-turbines have been undergone substantial transformations with respect to operational stability and noise emission, hydraulic designs are prompted to change according to market needs and requirements. One of the main factors threatening the mechanical structure of components represents the unstable operation in pump and turbine mode. Instabilities are typically accompanied by an intense increase in pressure pulsations that can be a main reason for vibration issues and resonance excitations in reversible pump-turbines. Avoiding instabilities during operation is, therefore, one of the major targets for competitive designs. This paper emphasizes the relevance of a thorough analysis of S-shape instabilities and provides an explanation of their underlying mechanisms based on analytical, numerical and experimental methods. It also addresses conflictive mechanisms behind a varying rotor-stator distance that could occur in terms of operational stability and rotor-stator interaction. The introduction of a new 3D-shaped guide vane design represents a further key outcome of this study. With respect to a varying rotor-stator distance, special attention has been paid to the description of influencing factors for turbine stability and pressure pulsations using three rescaled versions of an existing guide vane design. Series of model tests have been conducted on a test rig at ANDRITZ in Linz, Austria, revealing whether a measure is competitive based on the layout of a 2x330MW variable-speed pump-turbines plant.
LUMEN Turbopump: Preliminary Thermal Model
Authors: Saraf Anirudh Mukund , Traudt Tobias , Oschwald Michael 
Published: May 2021

Abstract
The DLR LUMEN (Liquid Upper stage deMonstrator ENgine) rocket engine comprises of two separate turbopumps, one each for Liquid Oxygen (LOX) and Liquified Natural Gas (LNG) supply. In both turbopumps, an identical bearing block separates the pump section from the turbine section. In the current design, the bearing block features an oil-jet lubrication system to cool and lubricate the bearings during operation. Cryogenic conditions at the pump-interface and high temperature conditions at turbine-interface impose thermal constraints on the selection of a suitable lubricant for the bearing assembly and the design of the lubrication system.
As a starting point to address this challenge, this paper presents a preliminary uncoupled finite element thermal model of the LUMEN LOX turbopump. The thermal model investigates the thermal behavior of the housing and rotor components in the bearing housing from start-up to shutdown of the turbopump. The model employs thermal worst case conditions to establish the operational thermal envelope of the turbopump system. Spatial and temporal evolution of the temperature at critical points within the bearing housing are reported.
The model, albeit the uncertainties rooted from its empirical nature, provides beneficial insight into the thermal characteristics of the turbopump assembly. This serves as a first estimate of the thermal constraints for the selection of lubricant oil.
The influence of casing treatment on the performance of a centrifugal pump
Authors: Li Yuan , Chen Hua , Li Xiangjun , Jiang Minghe , Wang Guinian 
Published: May 2021

Abstract
Centrifugal pumps may run under off-design conditions such as low flows. Under such conditions, back-flow may occur at the impeller inlet and block a part of the flow path and cause energy loss. Casing treatment has been widely used in centrifugal compressors to improve their performance at low flow conditions, but there is little in the open literature on the effect of casing treatment on the performance of centrifugal pumps. In this paper, a SC100-200 centrifugal pump is studied with a casing treatment. First, the CFD method employed was described and verified by the experimental results of the pump. CFD indicates that the starting point of the back-flow is around discharge coefficient of 0.111 of the pump, and the back-flow intensity gradually increases with the decrease of flow rate reaching another critical point at discharge coefficient of 0.061 where the back-flow upstream traveling distance suddenly increases significantly. Then a casing treatment is created in the inlet end-wall and front cover using a U-tube type configuration. The numerical simulation was carried and it is found that a part of the back-flow at the inlet and front-side cavity of the centrifugal pump is sucked to the U-tube of the casing treatment and returns to the pump inlet, the back-flow and entropy production at the impeller inlet are reduced, and the head and efficiency of the pump is little affected. Further research shows that the longer the length of the U-tube is, the stronger the suction effect will be, and the smaller the back-flow of the pump.
Evaluation of natural frequency, Campbell diagram and forced torsional vibration of deepwell pumps for the marine, oil and gas industry
Authors: Bayat M. , Sørensen H.L. 
Published: May 2021

Abstract
Deepwell marine and offshore pumps need to design in a way to present high performance and reliable lifetime. Deepwell pumps should be designed in a way to operate under offshore conditions. In order to investigate the resonance and find critical rotational speeds of the pump, it is needed to find the rotational natural frequency for undamped model. In order to avoid any resonance, the intersection points between natural frequency and excitation (1X and 2X) should not be in the interval of 90%-110% of operating speed, based on API standard (API 610). Deepwell pump structure is combination of motor, motor-shaft coupling and pumping configuration. Based on the size of tank and type of ship the length of whole deepwell pump can be more than 40 meters. Elastic rotating shafts connect with appropriate shaft-couplings with needed numbers of impellers and inducer. Small and linear angle of rotation theory are used to extract natural frequencies of deepwell pumps. Different damping scenarios are illustrated in detail. Holzer method is implemented to analyse torsional forced vibration. Free-free boundary conditions considered. Combination of discrete model, lumped mass model and finite element method are employed to present the Campbell diagram. Parametric strategy is used for forced torsional vibration analysis. It is found that how to model and consider the effective length of intermediate shaft in pumping configuration has effect on second natural frequency. It is seen that the first natural frequency of the whole system is highly depended on modelling of motor-shaft coupling. The results are compared when the whole pump is model by lamped mass model and finite element model. Results of this paper suggest that combination of three mentioned methods is acceptable and accurate. It is shown that Holzer method is suitable for torsional forced vibration analysis. The developed codes are verified with findings in the literature.
Assessment of the Influence of Boundary Layer Ingestion (BLI) on the Axial Fan
Authors: Masaki A , Ogushi S , Tsuruta R , Nishiwaki D , Sato T , Okai K , Kazawa J , Masaki D , Harada M 
Published: May 2021

Abstract
Boundary Layer Ingestion (BLI) is a technology which is effective to reduce fuel consumption of future commercial aircrafts. However, the inlet distortion caused by BLI has a negative on the engine performance. This paper investigates the effect of the inlet total pressure distortion on the aerodynamic performance of the fan rotor. Unsteady numerical analysis was conducted on JAXA TechClean Fan with circumferential distortion caused by BLI. As the result, under the high distorted condition, the peak efficiency of the rotor decreases by 0.622 points. It is found that the main factor of the efficiency reduction is tip-wall passage vortex.
Aerodynamic and Mechanic Analyses of An Asymmetrically Scalloped Radial Turbine
Authors: Wang Yu , Chen Hua , Ma Chao , Sun Jinhui 
Published: May 2021

Abstract
In order to reduce the aerodynamic efficiency loss of deeply scalloped radial turbines, asymmetrically scalloping of turbines’ backdisc has been invented for a number of years. However, the mechanism how this works and its mechanical implication have not been reported in the open literature. In this paper, taking the symmetrically scalloped turbine of a turbocharger for marine generator application as the baseline, two asymmetrically scalloped turbines were developed from it: one with scalloping bias to the pressure side, and the other to the suction side of the blades. Mechanic and aerodynamic analyses of these three turbines were carried out using ANSYS Workbench. The results indicate that the asymmetrically scalloped turbine with scalloping bias to the pressure side can reduce the backdisc-heat shield cavity leakage flow going into the blade suction surface through the scalloped backdisc, due to the influence of the high pressure near the pressure surface of the blade, thus decrease the size of vortices the leakage flow generated near the suction surface inside the blade passages and associated mixing loss. Compared to the symmetrically scalloped turbine, it increases the maximum principal stress by 0.39% and 5.2% at blade fillet and backdisc respectively, but the aerodynamic efficiency of the turbine is increased by 0.78% point at a turbine U/C value of 0.43, and the smaller the value of the U/C is, the greater the efficiency advantage will be. By contrast, the turbine with suction side bias scalloping shows the poorest aerodynamic performance, due to an increased leakage flow through its scalloped backdisc.
Animal waste use and implications to agricultural greenhouse gas emissions in the United States
Authors: Qin Zhangcai , Deng Shiyu , Dunn Jennifer , Smith Pete , Sun Wenjuan 
Published: May 2021

Abstract
The increasing production of manure is a challenge for livestock management systems as well as the global environment. Being traditionally, and still dominantly, used as fertilizers, land application of manure could preserve soil fertility and improve soil carbon sequestration. However, manure application also increases nitrous oxide (N2O) emissions that might outweigh the benefits of carbon gains. Here we quantify soil carbon change and greenhouse gas (GHG) emissions from corn production systems in the United States from a life-cycle perspective. We show that utilizing manure can reduce mineral fertilizers use, and therefore avoid GHG emissions that would otherwise occur due to mineral fertilizer production and application. As a result, corn produced under manure has a reduced intensity of GHG emissions (1.5 t CO2e ha−1 or 0.15 t CO2e t−1 corn grain), about 15% less than those under sole mineral fertilizers. Owing to a sizeable amount of avoided emissions counterbalancing N2O, the soil carbon gain derived from manure use can largely contribute to net climate change mitigation. It should be noted that GHG emissions estimation can be largely improved as more robust and recent data become available to better represent spatially specific land management and to integrate ecosystem models with life-cycle model. Future studies are merited to further assess the alternative fate of manure, and expand the system boundary to assess agriculture and livestock sectors holistically.
Machine learning analyses of remote sensing measurements establish strong relationships between vegetation and snow depth in the boreal forest of Interior Alaska
Authors: Douglas Thomas A , Zhang Caiyun 
Published: May 2021

Abstract
The seasonal snowpack plays a critical role in Arctic and boreal hydrologic and ecologic processes. Though snow depth can be markedly different from one season to another there are strong repeated relationships between ecotype and snowpack depth. In the diverse vegetative cover of the boreal forest of Interior Alaska, a warming climate has shortened the winter season. Alterations to the seasonal snowpack, which plays a critical role in regulating wintertime soil thermal conditions, have major ramifications for near-surface permafrost. Therefore, relationships between vegetation and snowpack depth are critical for identifying how present and projected future changes in winter season processes or land cover will affect permafrost. Vegetation and snow cover areal extent can be assessed rapidly over large spatial scales with remote sensing methods, however, measuring snow depth remotely has proven difficult. This makes snow depth–vegetation relationships a potential means of assessing snowpack characteristics. In this study, we combined airborne hyperspectral and LiDAR data with machine learning methods to characterize relationships between ecotype and the end of winter snowpack depth. More than 26 000 snow depth measurements were collected between 2014 and 2019 at three field sites representing common boreal ecoregion land cover types. Our results show hyperspectral measurements account for two thirds or more of the variance in the relationship between ecotype and snow depth. Of the three modeling approaches we used, support vector machine yields slightly stronger statistical correlations between snowpack depth and ecotype for most winters. An ensemble analysis of model outputs using hyperspectral and LiDAR measurements yields the strongest relationships between ecotype and snow depth. Our results can be applied across the boreal biome to model the coupling effects between vegetation and snowpack depth.
Physicochemical characterization of peel, flesh and banana fruit cv. raja [Musa paradisiaca]
Authors: Syukriani L , Febjislami S , Lubis D S , Hidayati R , Asben A , Suliansyah I , Jamsari J 
Published: May 2021

Abstract
All parts of a banana cv. Raja can be used as functional food and health or beauty products. The physicochemical properties of fruit peels, pulp and banana cv Raja need to be known to determine the type of processing because it can affect the final product processed. This research aimed were to determine the characteristics of banana cv. Raja Flour from peel, flesh and fruit and its minerals content. The results obtained from the analysis of moisture content ranged from 6.21 to 39.33%, ash content was 1.33-1.86%, protein content was 2%. The content of vitamin C in the peel, fruit and flesh of bananas is 32.3 mg/100 g, 7.18 mg/100g and 4.99 mg/100g respectively. The mineral content of potassium (K) and calcium (Ca), in banana peels, is higher than the flesh and fruit of bananas, such as 73.03% and 16.12%, while the content of phosphorus (P), magnesium (Mg) and chlorine (Cl) in The pulp was higher than the skin and banana fruit 10.52%, 6.58%, and 4.37% respectively. The crystalline structure of banana flour from banana peels, fruit flesh and fruit shows the same type is type A and the gelatinization temperature ranges from 74.85 to 76.90C within 8.6 to 10.6 minutes.
The productivity of paddy rice with the method of five seedlings clump-1 STSS used PHP mulch and furrow irrigation compared with several cultivation technology packages
Authors: Sunadi  , Utama M Z H , Badal B 
Published: May 2021

Abstract
Various cultivation technique innovations such as the SRI method with AWD irrigation system have been able to increase the productivity of paddy rice, but farmers are still reluctant to implement it because they are faced with weed problems. This study aimed to test the productivity level of several paddy rice cultivation technology packages. The treatment was 6 types of cultivation technology packages, namely: the SRI method, the method with 5 seedlings clump−1 of STSS, the legowo system 4:1, the SBSU, the method of 5 seedlings clump−1 STSS with PHP mulch and furrow irrigation, and conventional system. The seedling was planted at 12 DAS ages, except for the conventional system at 26 DAS ages with 4 seeds attached clump−1. The results showed that the type of paddy rice cultivation technology package generally affected the growth and yield components of paddy rice, except for the percentage of productive tillers, the number of grain panicle−1, and the harvest index. The method of 5 seedlings clump−1 STSS with PHP mulch and furrow irrigation resulted more in almost all parameters compared to all packages technology tested. The grain production is 7,250 t MDG ha−1 it higher than other technology packages production.
Expression induction of Serratia plymuthica UBCF_13 metalloprotease gene with various types of metal ions
Authors: Zulfitri R , Aisyah S N , Oktavioni M , Fatiah R , Jamsari J 
Published: May 2021

Abstract
Bacteria as biocontrol agents can produce hydrolytic enzymes, one of them is a protease which plays an important role to degrade cell membranes or plasmalemma in fungi composed of protein. Metalloproteases are proteases that contain one or two metal ions on their active sites. The role of metal ions in metalloproteases is to activate water molecules, which act as nucleophiles in the catalysis process. The metalloprotease function of Serratia plymuthica UBCF_13 is unknown, therefore this study aimed to determine the effective metal ion to induce the expression of the UBCF_13 metalloprotease gene. The metalloprotease gene from Serratia plymuthica UBCF_13 was ligated into a pGEM T-easy plasmid. The recombinant plasmid was transformed into Escherichia coli BL21 by the heat shock method. The metalloprotease gene expression was induced by IPTG and a combination of several metal ions namely Zn2+, Mn2+, Fe2+, and Ca2+. The highest gene expression was characterized by the thickest protein band based on the result of SDS-PAGE visualization with a molecular weight of 27 kDa after being induced by Fe2+ metal ions. Proteolytic activity of metalloprotease UBCF_13 was tested using solid LB media containing 2% skim milk. The longest clear zone diameter was obtained up to 0,83 cm after being induced by IPTG combined with Ca2+ metal ion. These results can be used as a reference for the expression of the UBCF_13 metalloprotease gene. However, further enzyme purification is to be able the enzyme as an antifungal compound.
Cloning of gyrB housekeeping gene from Serratia plymuthica UBCF_13
Authors: Azizah N , Fatiah R , Jamsari J 
Published: May 2021

Abstract

Serratia plymuthica strain UBCF_13 is a biocontrol agent that has the potential to inhibit pathogenic fungi. S. plymuthica has housekeeping genes, one of which is the gyrB gene. The housekeeping gene was cloned to be used as a template for standard curve creation regarding the correlation of gene copy number and Ct value in absolute quantification data. This study was conducted to provide the plasmid housekeeping gene gyrB from S. plymuthica which will be used as a template for standard curve creation in absolute quantification. The method used in this study were DNA genome isolation, PCR, ligation, and transformation. The result showed that the housekeeping gene gyrB has been successfully cloning based on the size of the estimated amplicon, which is 114 bp.
Optimization of growth regulators to induce callus in chili [Capsicum annuum] cv. Berangkai
Authors: Yunita R , Bagus F R M , Nova B , Rosadi F N , Jamsari J 
Published: May 2021

Abstract
The imbalance between demand and yield production causes the price of chili to rise sharply in the market at a particular time. One of the factors driving chili productivity to decrease is the attack of Geminivirus. Geminivirus that attacks chili plant is Pepper Yellow Leaf Curl Virus [PepYLCV]. and causing failure in chili production. Therefore, it is necessary to develop chili varieties that are resistant to PepYLCD by applying a combination strategy of genetic engineering and a tissue culture approach. However, the morphogenetic ability of chilies to regenerate into complete plants is low in developing this strategy. Optimizing growth regulators in the media of callus induction can increase the morphogenetic response of chilies. This research aimed to obtain the optimal composition of callus induction media. The results showed that the use of the media composition of 2.5 mg/L NAA + 2.5 mg/L IAA and 3.5 mg/L 2.4 D + 0.25 mg/L TDZ could initiate callus formation on the eighth day after induction. Both media compositions have a callus growth percentage of about 100%, which has a friable and yellowish-white callus morphology.