bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of whale-watching vessels on humpback whale calling behavior on an Icelandic foraging ground during the Covid-19 pandemic
Authors: Laute A , Grove TJ , Rasmussen MH , Smith A , Loisa O , Fournet MEH
Published: October 2022

Whale-watching vessels contribute to elevated ambient sound levels in marine habitats. The reduction in maritime tourism activities during the Covid-19 pandemic provided an unprecedented opportunity to study the acoustic response of marine mammals to noise associated with whale-watching activities. In this study, we used acoustic recordings, visual observations, and Automatic Identification System data to determine the changes in humpback whaleMegaptera novaeangliaecalling behavior associated with whale-watching vessels on a foraging ground in Skjálfandi Bay, Iceland. We compared pre-pandemic summer months (2018) with pandemic (2020) conditions to quantify reductions in vessel activity and determine changes in calling behavior. Broadband ambient sound pressure levels were low in both years (median ~90 dBRMS (25-1300 Hz)re 1 µPa). During the Covid-19 pandemic (2020), the number of whale-watching trips was reduced by 68.6%. The number of humpback whale call detections increased nearly 2-fold. Ambient sound pressure levels stayed the same. We found that humpback whales reduce their calling effort in the presence of vessel sound independent of the overall ambient sound. As whale-watching vessel traffic rebounds and continues to grow, demonstrating behavioral responses should inform management plans such as vessel codes of conduct and marine spatial planning.
TO THE PROBLEM OF NEW INDUSTRIALIZATION AND DISTRIBUTION OF PRODUCTIVE FORCES ON THE BASIS OF UPDATING THE HISTORICAL EXPERIENCE AND PRACTICES OF TRANSITION TO THE NEXT TECHNOLOGICAL MODES IN THE URALS AND RELATED TERRITORIES. PART 2. SOVIET PRACTICES
Authors:   Institute of Economics of the Ural Branch Russian of the Russian Academy of Sciences, Yekaterinburg, Russian Federation, LITOVSKIY VLADIMIR
Published: October 2022

The article examines the Soviet practices of regional industrialization, the signs of transition to the next technological order and the key parameters of its activation. This is done on the basis of ideas about energy production cycles and historical analysis of technological shifts in the basic sectors of the Ural industry, as well as on the basis of spatial approaches to its location. The possibilities of updating Soviet practices in modern conditions have been verified. To this end, two platforms for accelerating the transition to higher technological modes have been fundamentally studied: a) a platform based on internal potential and b) a platform based on external technological borrowing and imports. The relationship between the evolution of the administrative formations of the region and industrial complexes with the prevailing technological modes was studied in order to understand the features of the historical territory of the Urals. The influence of changes in the size of the territory in the Soviet and post-Soviet period has been studied in the formation of branches of the regional economy and industrialization, its relationship with territorial rent and sectoral differentiation has also been studied. It is shown that the size of administrative entities and industrial complexes of the territory is associated with the evolution of production energy cycles. This predetermines the status, as well as the historical perspective of the territory, its readiness for new industrialization.
CLIMATE POLICY IN LATIN AMERICA AND THE CARIBBEAN
Authors:   Ural Humanitarian Institute, Ural Federal University named after First President of the Russian Federation B.N. Yeltsin, Yekaterinburg, Russian Federation, KOVALEV YURI
Published: October 2022

The article deals with the climate policy of the countries of Latin America and the Caribbean (LA&C). The place of the region in the global structure of greenhouse gas production, their dynamics in the period 1990 - 2018 is analyzed, the relationship between the economic development of the region and the volume of GHG emissions is demonstrated. The main directions of the climate policy of the LA&C countries, the influence of political, social, and economic factors on the climate policy of individual countries are studied. Alternative ways and strategies of climate policy are shown on the example of Bolivia and Ecuador. An analysis of climate measures and conflict potential on issues of environmental modernization is given. In conclusion, the author's scheme for assessing the level of climate policy of the major states of the region according to their goals set in the framework of the Paris Agreement (UN NDC).
DECISION MECHANISM ON REPARATIONS BY THE STATE DEFENSE COMMITTEE DURING THE WAR
Authors:   Ural Federal University the first President of Russia B. N. Yeltsin, Yekaterinburg, Russian Federation, ZAPARIY VLADIMIR
Published: October 2022

In the article, based on the study of GKO materials that became available to the historical public as a result of declassification, the author considers the creation and development of reparation mechanisms. Interesting examples of this still little-studied process are given both in the field of ensuring the scientific potential of our science, and in the fields of communications and construction.
THE SOCIOCULTURAL ENVIRONMENT IN CLOSED ADMINISTRATIVE-TERRITORIAL FORMATIONS OF THE NUCLEAR INDUSTRY IN THE URALS
Authors:   Institute of History and Archeology, Ural branch of the Russian Academy of Sciences, Yekaterinburg, Russian Federation, KUZNETSOV VIKTOR , KONSTANTINOVA ALFIYA
Published: October 2022

The study of such a complex phenomenon as a closed nuclear town is difficult without highlighting separate logical lines and plots. The process of formation and development of the sociocultural environment in the Soviet and post-Soviet periods, determined by a number of macro- and microfactors (secrecy factor, high science intensity of production, and others) is chosen as one of these lines in this article. The authors characterize the sociocultural environment of Ural closed administrative-territorial formations (CATF) of the nuclear industry as a cultural phenomenon, where social and cultural processes closely interact (including activities of various actors in the creation and development of spiritual values, ideas and social norms). Various social institutions - from educational institutions to cultural and leisure institutions - were included in the field of the closed nuclear towns sociocultural environment. Their activities in the period from the second half of the 1940s to the beginning of the 2000s have been studied in this article.
ÜST YÖNETİCİ DEĞİŞİKLİĞİNİN KURUMUN PERSONEL BÜTÇESİNE YANSIMALARI: YEREL YÖNETİMLER ÜZERİNE BİR SENARYO
Authors: ÇELİK Mücahit , İNCEYOL Mustafa
Published: October 2022

İnsanlar, ortak amaçlarını yerine getirmek için bir araya gelirler ve sistematik bir iş birliği ile çalışacakları gruplar oluştururlar. İnsanların bu ortak amaçları gerçekleştirmeleri bir dizi iş birliği yapmalarına bağlıdır. Bu bağlamda işlerin belirli bir düzen içerisinde yürümesi ve aksamaması için işleri koordine edebilecek yöneticilere ihtiyaç olduğu bilinmektedir. Bazen örgüt, kurum veya kuruluş içerisinde düzenin bozulması veya işleyişin düzgün devam etmemesine bağlı olarak yönetici değişikliğine ihtiyaç duyulmaktadır. Kurumlarda iş ve eylemin idaresinde görevli bir üst yöneticinin, olası bir değişime uğramasında üst yönetici, kendi organizasyon yapısını oluşturmak isteyebilir. Yeni üst yönetici diğer yönetim kademesinde bulunan yöneticilere şans tanımadan, daha iyi anlaşabileceği ve daha iyi iş yapabileceğini düşündüğü kişiler ile çalışmayı tercih edebilmektedir. Bu durumda orta ve alt kademedeki eski yöneticileri farklı pozisyonlarda görevlendirir. Yeni pozisyonlara çoğunlukla pasif görev tanımları verilir. Yapılan bu çalışmada da bu tür pasifizasyonların kurumun personel bütçesine olan etkisi incelenmiştir.
Application of CGE Models as a Climate Policy Assessment Tool: Bibliometric Analysis
Authors: Dzyuba Yu. A. , Bakalova I. K.
Published: October 2022

In this study, we conduct a comprehensive bibliometric analysis aimed at structuring the existing economic literature that employs Computable General Equilibrium (CGE) models, and identifying key trends and main research areas. Using the authors’ methodology, we analyze the sample of 3760 domestic and foreign papers on CGE models published in 759 scientific journals in the period from 1995 to 2021. The main research questions are the applicability of the analyzed models for solving current environmental and economic issues and its relevance in modern realities. We show the potential of CGE models in the analysis of climate policy in Russia.
Digital cartographic basis for ensuring the effective use of agricultural land
Authors: Gileva L. N. , Podryadchikova E. D.
Published: October 2022

Active human economic activity has an increasingly diverse and tangible impact on the state of the land. One of the most important tasks of the state administration in the field of ensuring the rational use of land resources, as well as accounting and assessment of the state of agricultural land, is the creation of cartographic products, including digital maps of agricultural use using GIS systems, which systematize information on categories of land and land, according to their purpose, the current ecological state and sources of potential pollution of soils and territories are reflected, which provides an opportunity for effective management of the country's land resources.
Analisis overcurrent effect pada power supply linier 0-30 VDC menggunakan LM 723 di lab dasar elektronika dasar
Authors: Nisa Fauziah Sholikhatun , Dinata Oto Sunandar , Saukani Imam , Istiawan Fahmi Riski
Published: October 2022

ABSTRAK

Jenis catu daya yang sering digunakan untuk praktikum elektronika dasar adalah adjustable power supply karena membutuhkan arus relative rendah dengan tegangan bervariasi. Sistem keamanan yang umum digunakan untuk power supply biasanya berupa sekring. Jika terjadi arus berlebih dari sekring yang telah terpasang akibat kesalahan rangkaian atau pengkabelan akan membuat sistem proteksi ini aktif maka akan diperlukan pergantian sekring. Untuk memberi peringatan bagi mahasiswa saat terjadi arus berlebih di Laboratorium Elektronika Dasar Politeknik Negeri Malang, dirangkailah sebuah catu daya yang dapat diatur dengan menggunakan proteksi arus memanfaatkan IC LM 723 untuk level operasi catu daya 2 Ampere. Pada penelitian ini menggunakan 2 sistem proteksi yang diterapkan pada catu daya yaitu menggunakan buzzer sebagai sistem peringatan dan sekring sebagai pemutus arus. Penelitian ini akan menjelaskan tahapan pembuatan dan pengujian sistem. Sistem membatasi arus kerja maksimum 2.5 Ampere untuk beberapa variasi tahanan beban

 

ABSTRACT

The type of power supply that is often used for basic electronics practicum is adjustable power supply because it requires relatively low current with varying voltage. The security system commonly used for power supply is usually a fuse. If there is an overcurrent from the fuse that has been installed due to a circuit or wiring error will make this protection system active, a fuse replacement will be required. To give a warning to students when an overcurrent occurs at the Basic Electronics Laboratory of the State Polytechnic of Malang, a power supply that can be adjusted using current protection utilizes IC LM 723 for a power supply operating level of 2 Ampere. In this study, two protection systems were applied to the power supply, namely using a buzzer as a warning system and a fuse as a circuit breaker. This research will explain the stages of making and testing the system. The system limits a maximum working current of 2.5 Ampere for several variations of load resistance.
Pengaruh optimalisasi maintenance terhadap on load tap changer transformator daya 50 MVA 150/20 kV
Authors: Sulistyowati Sulistyowati , Nurhadi Slamet , Kharisma Dhimas Dhesah
Published: October 2022

Penyediaan energi listrik dengan yang kontinuitas penyaluran energi yang terjamin, dan kualitas tegangan yang baik sesuai dengan kebutuhan dunia industri perlu diperhatikan. Pengaturan tegangan (regulator tegangan) mutlak perlu dilakukan karena pengaruh tegangan input dari PLN selaku penyedia energi listrik yang fluktuatif, dan pengaruh perubahan beban yang berubah-ubah pada sisi konsumen. Adanya faktor diatas, penyesesuaian tegangan dengan cara melakukan perpindahan tap perbandingan kumparan dengan peralatan OLTC (On Load Tap Changer). Metode yang digunakan dengan cara menganalisis perubahan pola beban, fluktuasi tegangan input, serta maintenance keseluruhan transformator daya. Sesuai dengan estimasi life time OLTC transformator, didapatkan life time sekitar 80 bulan 25 hari (6 tahun, 6 bulan, 25 hari). Dan setelah waktu 80 bulan 25 hari ini terlampaui maka seharusnya transformator dan perangkat on load tap changer dilakukan service menyeluruh. Jika dibandingkan dengan operasional tap changer secara manual, dapat menghemat perpindahan tap changer sampai 4 kali perpindahan dalam 1 jamnya atau sekitar 34560 kali perpindahan tap dalam 1 tahun dan didapatkan perbaikan sebesar 57,14%.
ABSTRACT
It is necessary to pay attention to the supply of electrical energy with guaranteed continuity of energy distribution, and good voltage quality in accordance with the needs of the industrial world. Voltage regulation (voltage regulator) absolutely needs to be done because of the influence of the input voltage from PLN as a provider of fluctuating electrical energy, and the influence of changing load changes on the consumer side. The existence of the above factors, voltage adjustment by changing the coil comparison tap with OLTC (On Load Tap Changer) equipment. The method used is by analyzing changes in load patterns, fluctuations in input voltage, and overall maintenance of power transformers. In accordance with the estimated life time of the transformer OLTC, the obtained life time is around 80 months and 25 days (6 years, 6 months, 25 days). And after the 80 months and 25 days have passed, the transformer and the on load tap changer device should be thoroughly serviced. When compared with manual tap changer operations, it can save up to 4 times the displacement of the tap changer in 1 hour or about 34560 times the displacement of the tap in 1 year and an improvement of 57.14% is obtained.
A Ray Tracer for optimizing solar concentrating systems: The case of discretized Compound Parabolic Concentrator
Authors: Lwiwa Casiana Blasius , Nydal Ole jørgen
Published: October 2022

Concentrating solar systems use reflective surfaces to concentrate sunlight onto a small area, where it is absorbed and converted to heat. Many classes of concentrating collectors such as Compound Parabolic Concentrators (CPCs), parabolic dish and parabolic trough are available, each with different concentrating ratio and maximum absorber temperature, depending on the type of applications. A simplified 3D Compound Parabolic Concentrator (CPC) with 2 rings and 4 sectors has been designed. The designed CPC is cost effective as it requires only 8 mirrors to cover the reflector surface. It does not require sun tracking, but have capability to accept incoming solar radiation over a relatively wide range of angles. For further capturing of the solar radiations, tilting of the CPC during a day can be made a few times. This study aims to model the discretized 3D CPC using the ray tracing, to optimize the CPC for achieving optimal interceptions on a 0.2 m diameter cylindrical absorber, placed inside the CPC. The ray tracing methodology is presented together with the results of the interceptions on the cylindrical absorber using the discretized CPC. Results show the effect of tilting the discretized CPC is not very strong as the interception values are slightly reduced and the curves a little bit not symmetric around the normal sun angles.
Experimental PDE solver in Julia – comparison of flux limiting schemes
Authors: Farzin Amir , Barahmand Zahir , Lie Bernt
Published: October 2022

Finite Volume Methods (FVM) are high quality methods for solving conservative/hyperbolic partial differential equations (PDEs). A popular class of high-resolution methods utilize a nonlinear combination of low order methods and high order methods via flux limiting functions. Another class of high-resolution methods is the class of weighted essentially non-oscillatory (WENO) schemes. Here, the focus is on flux limiting schemes. An experimental finite volume (FV) semi-discrete solver for systems of hyperbolic PDEs has been implemented in Julia, utilizing Julia’s DifferentialEquations.jl package for handling the time marching. A first order upwind formulation is used for the low order method, and a central second order formulation is used for the high order method. The PDE can be provided either in flux form, or in quasi-linear form. In the former case, automatic differentiation (AD) package ForwardDiff.jl is used to compute the Jacobians of the flux vector. Package LinearAlgebra.jl is used to compute the eigenspace of the Jacobians. The implementation allows for up to 3 internal/external coordinates. More than a dozen flux limiting functions are given, with the possibility of the users to write their own flux limiters. The implementation allows for user provided spatial discretization points, and source terms in the PDE. In this paper, we will compare various flux limiting schemes for PDEs with analytic solutions, and will also compare flux limiting schemes for a simple granulation model (layering). Possible extensions of the experimental implementation include: (i) higher order methods, (ii) more extensive support for boundary conditions, (iii) improved support for source terms.
Comparison and Application of Multi-Rate Methods for Real-Time Simulations of Production Systems
Authors: Klingel Lars , Kamm Valentin , Verl Alexander
Published: October 2022

A distributed simulation makes it possible to couple simulation tools and lays the foundation for the usage of multicore capabilities to decrease the calculation time. In consequence the simulation is partitioned on multiple simulation tasks. If simulation tasks with different integration step sizes are used, the configuration is called multi-rate simulation. In real-time simulations the tasks are calculated parallely, which means that fast tasks do not wait for the simulation result of slower tasks. A sequential approach where fast tasks wait for slower tasks would slow down the overall simulation and therefore tear the real-time requirements. In a real-time multi-rate approach, signal processing of the coupling signals between the tasks is required. For this signal processing, multi-rate methods are used. Easy multi-rate methods lead to stepped signals in the faster task, because the slower task does not provide a new calculated signal at each timestep of the faster task. In this work further methods are investigated in an industrial real-time simulation environment. The analysis contains continuous and discontinuous as well as energy conserving methods. It is shown how these different methods perform for various kinds of signals. The methods are compared and evaluated on signals with different characteristics, which allows a recommendation for the choice of a method in a specific simulation scenario. The application of the multi-rate methods is shown on an example virtual commissioning simulation of an industrial robot. It shows that the right choice of a multi-rate method has a big impact on the overall simulation result.
Optimal operation of grid-connected hydropower plants through voltage control methods
Authors: Melfald Emil G. , Øyvang Thomas
Published: October 2022

The ongoing decarbonization, and the rapid increase in renewable penetration in the electric grid, will demand enhanced flexible operational schemes of the conventional hydropower plants. This paper explores a grid-connected hydropower plant’s best-efficiency operating conditions when meeting the renewable energy transition. Power loss models combined with various voltage control methods are investigated for achieving optimal operation. This simulation study is carried out on a static F13Single Machine Infinite Bus (SMIB) environment to perform voltage control comparisons. Simulations show that the plant and grid power loss models can be utilized in an optimal controller setting to increase the accumulated average efficiency (AAE). However, optimal controllers had slow prediction times, and therefore a Reinforcement Learning (RL) method, A2C, has been trained to learn an optimal control policy that maximizes system efficiency. The RL agent supersedes the optimal control techniques with up to 40 times faster prediction times.
Process simulation of CO2 absorption data fitted to performance efficiency at TCM Mongstad
Authors: Øi Lars Erik , Sæter Njål , Razi Neda , Karunarathne Sumudu
Published: October 2022

This work's first aim is to fit the simulated results to pilot plant data from Test Centre Mongstad (TCM) for both high and low CO2 exhaust gas inlet concentrations. The next aim is to evaluate whether fitted parameters for one scenario (a set of experimental data under specified conditions) give reasonable predictions under other conditions. The scenarios at TCM have been simulated in both a rate-based model in Aspen Plus (RateSep) and an equilibrium-based model in Aspen HYSYS. The rate-based model’s performance data were fitted by only changing the liquid hold-up factor (multiplied with the hold-up estimated by the Bravo/Rocha/Fair correlations) to obtain the experimental CO2 removal efficiency. In the equilibrium-based model, a Murphree efficiency (EM) was specified for 24 or 18 stages (meter of packing) to fit the CO2 removal efficiency and the temperature profile from performance data. The specified EM profiles were then used to fit performance data for other scenarios by adjusting only an EM-factor, multiplying all the EM values in an EM profile. The performance (CO2 removal and temperature profile) was reasonably simulated for each given scenario for all the models. It is shown in this work that the use of the liquid hold-up factor (and not the interfacial area factor) is convenient to fit the rate-based model to the pilot plant data. Using fitted parameters at low CO2 inlet concentration to predict performance at high concentration needed an adjustment factor (liquid hold-up factor or EM-factor) to obtain correct CO2 removal predictions. A liquid hold-up factor of 0.72 and an EM-factor of 1.72 fitted to performance data for high CO2 concentration at TCM gave reasonable predictions compared to performance data for high CO2 concentration from the Esbjerg pilot plant.
Simulation-Based Life Cycle Assessment for Office Building Façade: A Case Study of the Leadenhall Building in London
Authors: Khameneh Tahmineh Akbarinejad , Barahmand Zahir , Samarakoon Gamunu
Published: October 2022

High-rise glazing systems are among the most important components affecting energy efficiency. Through the lens of Life Cycle Assessment, glass has always been an unlikely material for large buildings due to its considerable energy consumption throughout the pre-use and post-use phases. Moreover, the use of high-tech materials has a negative impact on the environment. Therefore, the present study aims to assess a comparative life cycle of four different glazing system technologies (BIPV, smart glass, low-E, and double glazing) representing the most used commercial high potential glazing systems. The next step has been optimized for the Leadenhall iconic tower as the case study. In this analysis, energy simulation is combined with life cycle assessment to investigate the environmental impacts. ZEB-COM tool, Rhino®, and Grasshopper® have been used to calculate emissions, 3D modeling, and energy modeling, respectively. The results reveal that BIPV achieved 37% of total energy-saving and stood first. A hybrid solution (two glazing systems) has been proposed to eliminate negative aspects and increase livability. Although it can generate almost 30% less energy than the complete BIPV installation, with a specific design by the authors, it can cover aesthetic concerns in this system and compensates for 27% of the total energy demand of the Leadenhall project.
Density and viscosity correlations of aqueous solvents for amine-based CO2 capture
Authors: Karunarathne Sumudu , Okoro John Ikechukwu , Neupane Saroj , Øi Lars Erik
Published: October 2022

Density and viscosity data are essential in designing process equipment and process simulations in the amine-based CO2 capture process. In literature, semi-empirical and empirical correlations for density and viscosity were fitted to measured data available in the literature and the goodness of fit by calculating Average Absolute Relative Deviations (AARDs %) were examined. The correlations based on excess properties give insights on intermolecular interactions and packing efficiency in multicomponent liquid mixtures.In this study, correlations for density, excess density (ρE, ln(ρE)) viscosity and excess viscosity (ηE, ln(ηE)) were examined for binary aqueous mixtures (Monoethylethanolamine) EMEA (1) + H2O (2) and (Monoethylethanolamine) EMEA (1) + (Diethylethanol amine) DEEA (2) to represent the measured density and viscosity. The Redlich and Kister type polynomials were used to fit the excess properties and the goodness of fit was determined by calculating AARD%. The fitted experimental data at different mole fractions and temperatures were able to acquire a good accuracy. Highest deviation for density correlations of EMEA + DEEA mixtures was observed with AARD 0.135 % and AMD 2.98 kg·m-3. For the EMEA + H2O mixtures, the highest deviation was observed with AARD 0.23 % and AMD 8.38 kg·m-3. Viscosity correlations showed a highest deviation for the EMEA + DEEA mixtures in which AARD was 5.2 % and AMD was 1.2 mPa·s. For the EMEA + H2O mixtures, the highest deviation observed with AARD was 1.1% and AMD was 0.75 mPa·s.McAllister’s kinematic viscosity model is a semi-empirical model based on Eyring’s theory for viscosity. The kinematic viscosity data were fitted to McAllister’s three-body model to investigate whether the suggested intermolecular interactions in the model are capable of describing the nature of the binary mixtures. The results indicated a good agreement between data and model with accuracies R2 = 0.99 and AARD 2% for EMEA + DEEA mixtures and AARD 6% for EMEA + H2O mixtures.
Himalayan Run-Off River Power Generation Modelling for Power Security in Evolving Weather Conditions
Authors: Dahal Swaechchha , Øyvang Thomas , Hegglid Gunne John , Jha Shailendra Kumar , Chhetri Bhupendra Bimal
Published: October 2022

Extreme black-swan occurrences like earthquakes, glacial lake outbursts, flash floods, landslides, etc. are important concerns in Himalayan countries like Nepal, which are highly susceptible, geologically active, and exquisitely fragile. Nepal generates 97 percent of its electricity from hydropower, where 56.08 percent of it is coming from seasonal run-off-river (RoR) hydro plants. Landslides and mudflows are common in the monsoon, and low discharge is common in the winter season. These RoR plants must be able to withstand high-impact events like earthquakes and lengthy droughts in order for the Nepalese grid to remain secure. This study gives a presentation and overview of previously occured natural hazards in Nepal related to hydropower plants. In particular, the 2014 Sunkoshi landslide and the 2021 Melamchi flood are evaluated as extreme events and their impacts on hydropower plant has been studied. In addition, an in-depth investigation on a ROR plant is carried out. Moreover, the water discharge and extreme rainfall peaks in time series data is evaluated using an ARIMA-based model. This paper shows the feasibility of predicting the energy produced by a run-off river hydropower plant. The purpose is to forecast discharge and hence the ROR power generation with the aim to facilitate the hydropower operators for their availability declaration which will again help in the overall energy planning. The results are discussed together with performance metrics, and indicates that the implemented technique is promising.These predictions can be further used for planning and estimating the power generation on a more complex level.
Unsteady flow analysis of hinged and sliding door openings
Authors: Kihlberg Fredrik , Hermansen Øystein Formo , Chaudhuri Arnab
Published: October 2022

Existing thermal condition and indoor air quality have a big impact on our work performance, comfort, and health in an indoor environment. Apart from many other parameters, door motions and human movements play crucial role in mass and thermal exchange affecting safety and/or energy management issues in various situations. An isolation room in a hospital setup, for instance, helps to protect patients and staff against the risk of infection by airborne pathogens. Another example is cold storage room facilities, where temperature and moisture control are the key parameters for an optimal operation and energy usage. In this study, we present a transient flow analysis of door motions in indoor environment. The flow physics is resolved by solving 3D compressible RANS (Reynolds-averaged Navier-Stokes) equations together with the energy and species transport equations and two-equation turbulence models utilizing an overset mesh strategy to address the rigid body motion of doors in a relevant fluid domain involving air and sulfur hexafluoride (SF6). Simulations are performed for three different types of doors, namely a hinged door, a two-way sliding door, and a sliding door considering door opening and closing phases. Transient flow-field data through the door opening area have been processed and a comparative analysis is performed considering the mass flux of the constituents, normal velocity, cumulative mass exchange through the different doors.
Evaluation of Complex Spray Behaviors of Sprinkler Spray Using FDS
Authors: Ramachandran Rajath , Lundberg Joachim
Published: October 2022

It takes money, time, and energy to set up an experimental grid to measure the effectiveness of fire suppression parameters. Therefore, computational fluid dynamics (CFD) is an alternative in all fields as consequences modeling. Fire Dynamic Simulator (FDS) is a CFD software developed by the National Institute of Standards in Technology (NIST) to model and generate the results for the spray models. FDS uses Large Eddy Simulation (LES) to represent turbulence. The current study utilizes FDS to investigate the extinguishing efficiency of sprinkler spray on e general fire. The study focuses on analyzing the effectiveness of suppression parameters using complex (polydisperse) in contrast to the simplified (monodisperse) representation of the spray with- and without a fire scenario of a 2560 kW propane fire. Measurements were taken by digitally enabled Phase Doppler Particle Analyzer (PDPA) to measure the fire suppression parameters such as number concentration, droplet size distribution (DSD) & velocity distribution. The measurements were taken 1.5 m downstream of the sprinkler. The suppression parameters are compared with monodisperse and polydisperse with and without fire. Thus, the suppression parameters have been compared to measure the effect.
Predictive Maintenance of Pumps at ‘Den Magiske Fabrikken’, Using Machine Learning Techniques
Authors: Holm Martin , Yalcin Ozgur , Pfeiffer Carlos , Viumdal Håkon
Published: October 2022

In this work, we investigate machine learning methods to predict the failures of progressive cavity pumps (PCP). The PCPs are located in a biogas plant, Den Magiske Fabrikken, in Norway, which is transforming food waste and animal manure to biogas and biofertilizer. Available measurements were pump on-signal, speed, current, torque and control signal, inlet flow, inlet pressure and outlet pressure, and several vibrations derived signals.Five categories were defined to categorize the operation of the pumps as: “stopped”, “normal running”, “7 days from failure”, “1 day from failure” and “1 hour from failure”. The objective was to train a Machine Learning model to predict these categories. The data was pre-processed to clean gross outliers and scale the signals using different techniques.This paper presents results from the same Long Short-Term Memory (LSTM) model using two different approaches for scaling the data. The results are evaluated using confusion matrices where one scaling method clearly improves the results when testing on new data points. Further work is presently being carried out to implement the selected methods in real-time and to generalize the model (Holm, 2022).
A fast and effective method for modelling and optimizing district heating systems in the Modelica language
Authors: Li Haoran , Hou Juan , Nord Natasa
Published: October 2022

A district heating system is a centralized energy system that supplies heat to end users such as buildings and industrial facilities. This centralized system may have multiple heat sources, a complex distribution network, and a large number of end users. Moreover, the heat distribution and utilization processes entail tumultuous thermal dynamics. Therefore, modelling and optimizing such a system generally demands arduous labour and necessitates powerful computing resources. To overcome these difficulties, this study introduced a fast and effective method for modelling and optimizing district heating systems using the Modelica language. Firstly, a simplified district heating system model was developed. This simplified model lumped all the end-users into a single thermal pinot with critical physical constraints. Meanwhile, the distribution network was simplified into two pipelines: supply and return. In addition, a one-dimensional discrete model was used to describe the behaviours of water tank thermal energy storage. Other essential components, like central and distributed heat sources, were modelled using basic mass and energy balance equations. Afterwards, two optimization frameworks were formulated, which incorporated the developed system model: a long-term optimal operation framework aimed at a yearly level open-loop optimization with a two-hour resolution, and a model predictive control framework aimed at a daily level close-loop optimization with a one-hour resolution. The proposed method was tested numerically on a university campus district heating system in Norway on a personal computer. Model validation showed that the proposed modelling approach could capture the key characteristics of the studied system. Optimization results demonstrated the effectiveness of the proposed optimization frameworks both for the long-term and short-term optimization.
Offshore CO2 Capture from gas turbine with low investment optimized using Aspen HYSYS
Authors: Øi Lars Erik , Fazli Fatemeh , Thapa Rajan
Published: October 2022

CO2 capture from gas turbine exhaust gas is a possibility for CO2 emission reduction on oil and gas production platforms. A standard process is based on absorption in monoethanol amine (MEA). A challenge is that the cost of size and weight for the process equipment is higher than on a land-based process. A standard process based on CO2 absorption into (MEA) is simulated in Aspen HYSYSTM. The equipment cost was obtained from Aspen In-plant Cost EstimatorTM. The base case is based on assumptions which are in earlier works assumed to be close to optimum for a land-based process with a heat consumption of 3.5 MJ/kg removed CO2. Different parameters as the number of stages in the absorption column and the minimum temperature approach are varied in the direction expected to be more optimum for an offshore application. It is expected that a lower absorption column and smaller heat exchangers are more optimum offshore even though the heat consumption will increase. Parametric studies were performed at 90 % capture efficiency. Suggested conditions for an offshore application with 87 % capture efficiency are 13 m absorber packing height and 15°C minimum approach temperature due to a decrease in equipment cost, size and weight. This is expected to balance the increase of heat consumption to approximately 5.5 MJ/kg CO2 removed.
Eulerian-Lagrangian simulation of air-steam biomass gasification in a bubbling fluidized bed gasifier
Authors: Samani Nastaran A. , Eikeland Marianne S.
Published: October 2022

To numerically study biomass gasification in a three-dimensional bubbling fluidized bed, a CFD-DEM (computational fluid dynamics – discrete element method) model with heat transfer and homogeneous and heterogeneous chemical reactions is implemented. An ideal reactor model is used for the air-steam bubbling fluidized bed (BFB) gasification reactor assuming perfectly mixed solids and plug flow. A validated computational particle fluid dynamics (CPFD) model has been applied to investigate the sensitivity analysis of mesh grids as well as to find the optimum number of grids. The result shows that 7452 grid cells are the optimal number of cells for the existence BFB gasifier. The effects of key process operating parameters such as steam to biomass ratio (SB), as well as temperature shows that by enhancing the SB ratio or reactor temperature, gas yields increase. H2 and CO2 concentrations promote by increasing the steam to biomass ratio while CO and CH4 production drop. The optimal value of SB for the gasification process can be found in the range of 0.3 to 1.
CFD Simulations of Flow Jetting Impact and High Erosion Region in a Production Choke and its Downstream Spool
Authors: Perinpasivam Agastian , Bagalkot Nikhil , Keprate Arvind
Published: October 2022

Erosion wear, a rather well-known problem in the petroleum and transport industry. Over the years there have been many different models suggested to estimate the erosion. Each model uses unique equations and is suited for different types of geometries, which gives different flow profiles and erosion patterns. It is critical to know where the erosion wear occurs and at what magnitude the system is located at to predict and economically create a choke valve design. In this study, computational fluid dynamics (CFD) is used to investigate erosion on a production choke valve and its downstream spool. There are three main steps to predicting erosion wear using CFD analysis: flow model, particle tracking and calculating the erosion wear from particle interaction. The results indicate that pressure drop affects the velocity jet shape and impact region. In the 50% opening case, the pressure drop creates a wide jet stream region that, in turn, will cause an increased wall impact region. When the opening decreases, to 35% and 25%, the jet stream gets more focused. The velocity jet impacts a smaller area of the pipe wall, which in turn creates possibilities for increased erosion rate. The high pressure drop in the 15% opening case creates a high-focused jet stream in the middle of the downstream pipe, leading to low wall interaction.
Simulation of different scenarios for resource utilization. Uncertainties, availability, and fair distribution of global resources
Authors: Dahlquist Erik , Hellstrand Stefan , Martinsen Madeleine
Published: October 2022

In this paper scenarios are made simulating how demand can be predicted for different materials and resources for the future when we develop new technologies to build the sustainable society for everyone. How does recycling efficiency impact total demand for virgin resources? This also means a fair distribution including all people, but with a bit different demand depending on where people live. In hot countries cooling is important, while heating in cold. But how will global warming affect this? And how can solutions like EV with batteries and H2 with fuel cells (FC), new materials for heat and cold storage etc change the demand for different materials and resources? Different scenarios are simulated, and the results discussed.
Modelling of liquid injection of ammonia in a direct injector using Reynolds-averaged Navier–Stokes simulation
Authors: Gaucherand Jessica , Netzer Corinna , Lewandowski Michal T. , Løvås Terese
Published: October 2022

Ammonia as a fuel has gotten attention in the past years to enable decarbonization for internal combustion engines. There is a need to understand the behavior of the liquid fuel in direct injection engines, a crucial step of the engine cycle. Injection impacts the mixture formation in the cylinder, equivalence ratio, combustion and pollutants formation. Liquid ammonia is expected to behave significantly different than traditional fuels during the injection phase and hence requires to be investigated. Indeed, recent experimental research has highlighted the appearance of flash boiling during injection of ammonia spray under engine-relevant conditions. The high volatility is also expected to influence the cavitation behavior. Cavitation is the partial vaporization of the liquid typically caused by locally increased velocity resulting in a pressure drop, when the fluid enters an orifice with sharp edges. One parameter controlling cavitation is therefore the geometry, but cavitation is also influenced by the fuel’s property and the boundary conditions. This study presents 3-D RANS simulations performed with CONVERGE CFD of the internal flow of a Gasoline Direct Injector (GDI), operating with liquid ammonia. The transient simulations account for the injector needle movement. Simulations capture the presence of both vapor and liquid in the nozzle head. These results from the simulations will provide input data for separate spray simulations with the same engine geometry, as well as support the development of a 0-D model that will be important for design purposes. Preliminary results predict a liquid discharge coefficient of less than 0.1 at the outlet for injection in atmospheric conditions.
Anaerobic Co-Digestion of Products from Biosolids Pyrolysis – Implementation in ADM1
Authors: Flatabø Gudny Øyre , Bergland Wenche Hennie
Published: October 2022

Pyrolyzing biosolids can decrease volume and increase value of solids while anaerobic digestion of gas and liquids from the process could increase overall methane production. Prediction of process behavior and biogas yield through simulation is valuable when considering new substrates for anaerobic digestion. In this study, gas and liquids from biosolids pyrolysis were implemented in Anaerobic Digestion Model No 1 (ADM1) together with a stream of thermally hydrolyzed sludge/food waste used in an industrial biogas plant. Average operational data from the industrial plant was used to calibrate the base scenario in ADM1, achieving a good fit. Simulation scenarios evaluating two hydrolysis constants for the pyrolysis liquid showed minor differences at the load simulated and simulated variations in composition of the liquid showed minor differences. Simulation of adding a relevant stream of pyrolysis liquid and gas together increased methane production by 7 % but decreased overall methane yield from 63 % to 61 % compared to the base scenario.
On physics-informed neural networks for quantum computers
Authors: Markidis Stefano
Published: October 2022

Physics-Informed Neural Networks (PINN) emerged as a powerful tool for solving scientific computing problems, ranging from the solution of Partial Differential Equations to data assimilation tasks. One of the advantages of using PINN is to leverage the usage of Machine Learning computational frameworks relying on the combined usage of CPUs and co-processors, such as accelerators, to achieve maximum performance. This work investigates the design, implementation, and performance of PINNs, using the Quantum Processing Unit (QPU) co-processor. We design a simple Quantum PINN to solve the one-dimensional Poisson problem using a Continuous Variable (CV) quantum computing framework. We discuss the impact of different optimizers, PINN residual formulation, and quantum neural network depth on the quantum PINN accuracy. We show that the optimizer exploration of the training landscape in the case of quantum PINN is not as effective as in classical PINN, and basic Stochastic Gradient Descent (SGD) optimizers outperform adaptive and high-order optimizers. Finally, we highlight the difference in methods and algorithms between quantum and classical PINNs and outline future research challenges for quantum PINN development.
Image encryption using fractional integral transforms: Vulnerabilities, threats, and future scope
Authors: Kaur Gurpreet , Agarwal Rekha , Patidar Vinod
Published: October 2022

With the enormous usage of digital media in almost every sphere from education to entertainment, the security of sensitive information has been a concern. As images are the most frequently used means to convey information, the issue related to the privacy preservation needs to be addressed in each of the application domains. There are various security methods proposed by researchers from time to time. This paper presents a review of various image encryption schemes based on fractional integral transform. As the fractional integral transforms have evolved through their applications from optical signal processing to digital signal and digital image processing over the decades. In this article, we have adopted an architecture and corresponding domain-based taxonomy to classify various existing schemes in the literature. The schemes are classified according to the implementation platform, that may be an optical setup comprising of the spatial modulators, lenses, and charge-coupled devices or it can be a mathematical modeling of such transforms. Various schemes are classified according to the methodology adopted in each of them and a comparative analysis is also presented in tabular form. Based on the observations, the work is converged into a summary of various challenges and some constructive guidelines are provided for consideration in future works. Such a narrative review of encryption algorithm based on various architectural schematics in fractional integral transforms has not been presented before at one place.
Crowding-induced morphological changes in synthetic lipid vesicles determined using smFRET
Authors: Quinn Steven D. , Dresser Lara , Graham Sarah , Conteduca Donato , Shepherd Jack , Leake Mark C.
Published: October 2022

Lipid vesicles are valuable mesoscale molecular confinement vessels for studying membrane mechanics and lipid–protein interactions, and they have found utility among bio-inspired technologies, including drug delivery vehicles. While vesicle morphology can be modified by changing the lipid composition and introducing fusion or pore-forming proteins and detergents, the influence of extramembrane crowding on vesicle morphology has remained under-explored owing to a lack of experimental tools capable of capturing morphological changes on the nanoscale. Here, we use biocompatible polymers to simulate molecular crowding in vitro, and through combinations of FRET spectroscopy, lifetime analysis, dynamic light scattering, and single-vesicle imaging, we characterize how crowding regulates vesicle morphology. We show that both freely diffusing and surface-tethered vesicles fluorescently tagged with the DiI and DiD FRET pair undergo compaction in response to modest concentrations of sorbitol, polyethylene glycol, and Ficoll. A striking observation is that sorbitol results in irreversible compaction, whereas the influence of high molecular weight PEG-based crowders was found to be reversible. Regulation of molecular crowding allows for precise control of the vesicle architecture in vitro, with vast implications for drug delivery and vesicle trafficking systems. Furthermore, our observations of vesicle compaction may also serve to act as a mechanosensitive readout of extramembrane crowding.