bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental investigation of bladeless expander with an incompressible fluid
Authors: Renuke Avinash , Reggio Federico , Pascenti Matteo , Traverso Alberto 
Published: December 2022

Abstract
For small-medium heat pumps and small-scale energy storage (e.g., hydro) and other small-scale applications (up to 10kWe), an economical, reliable, durable, robust, and acceptable performing bladeless expander is an attractive technology. In this article, experiments are performed on a bladeless expander of 1kW design power with water as a working fluid. The complete expansion is in the subcooled liquid phase with an overall pressure drop across the expander in the 2-14 bar range. The water expander is designed as a similitude case study for a butane heat pump, where such a bladeless expander could replace the expansion valve recovering untapped energy from isenthalpic to isentropic expansion. Unlike conventional bladed expanders, the present bladeless expander consists of several co-rotating compact disks, closely spaced and parallelly mounted on the shaft which transmits torque using wall shear forces. The present expander design is an improved version resulting from the detailed loss characterisation done on earlier air expanders.
The article begins with the definition of design conditions for water expander starting from the expected butane expansion in the heat pump, fully inside the liquid region. The rotor design of a bladeless expander is outlined using dimensionless parameters that dictate the performance features. The turbine is designed for 1kW of power output and 2kg/s mass flow with an overall pressure drop of 14 bar with a rotational speed of 8000 rpm. The resulting turbine rotor consists of an 80mm disk outer diameter, 120 disks and a 0.1mm gap between them. An experimental test rig employing water as a working fluid is described. Experiments are conducted for overall pressure drop ranging in the 2-14 bar interval, with a maximum rotational speed of 6500 rpm. The performance is recorded with two different stator configurations, having two different throat dimensions for varying mass flow at maximum inlet pressure. Peak total to static efficiency of 30% is obtained with a net power of 670 W at ∼3000 rpm. An experimental ventilation loss (end wall viscous disk friction) is performed with both water and air as working fluids to estimate the power loss. It is found that ventilation loss is the major source of loss in the present turbine prototype with a power loss of 250W@3000 and 1100W@8000 rpm, varying quadratically with rotational speed. It is finally concluded that the expander performance is promising because ventilation losses can be potentially reduced with established strategies used in conventional expanders.
Optimization of Solar District Heating & Cooling Systems
Authors: Brumana G. , Franchini G. , Ghirardi E. , Ravelli S. 
Published: December 2022

Abstract
The present work proposes a comparison between three solar-powered district heating and cooling systems, namely: 1) centralized district heating & cooling (DHC) system; 2) 5th-generation district heating & cooling (5GDHC) system and 3) individual AC plants (HHC, Home Heating and Cooling), in different climate conditions. Thermal loads are evaluated by transient simulations of a residential compound featuring 56 detached houses for three different Italian climates: (1) a Mediterranean region on the seaside (Palermo, I), (2) a temperate climate in Central Italy (Roma, I), and (3) a cold-temperate climate in Northern Italy (Bolzano, I). The DHC system shows the highest efficiency in terms of energy-savings, whatever the location. The 5GDHC system reaches a compromise between installation and operational costs.
Development of a Test Bench for Biogas-fueled Internal Combustion Engines Working in Cogeneration Mode for Residential Applications
Authors: Ancona M. A. , Branchini L. , Catena F. , De Pascale A. , Melino F. , Ottaviano S. 
Published: December 2022

Abstract
The aim of this paper is the presentation of a test bench developed and installed at the Laboratory of the University of Bologna: the test bench has been developed for internal combustion engines, working as cogeneration units and fueled with biogas. In this perspective, the test bench purpose is to experimentally test and optimize the operation of cogenerative internal combustion engines on varying the boundary conditions, in terms of both biogas composition and electric and thermal load. Other main components are the anaerobic digester, a multi-fuel internal combustion engine, the electric load and a heat exchanger for the heat recovery from the exhaust gases and connected to a water circuit representing the thermal user. The test bench has been equipped with the opportune measurement devices, as well as with a specifically developed data acquisition system. First experimental tests, carried out on varying the methane content within the CH4-CO2 blend and the electric load allowed to optimize the test bench in terms of heat recovery section and air supply to the engine.
Model and transient Control strategy design of an Organic Rankine Cycle Plant for waste heat recovery of an Internal Combustion Engine
Authors: Giovanni Giardiello , Francesco de Nola , Giuliana Ghezzi , Alfredo Gimelli , Raffaele Iossa , Giuseppe Langella , Bernardo Sessa 
Published: December 2022

Abstract
The multi-sources hybrid polygeneration energy systems are of great interest and topicality as they are one of the most promising technologies in the European’s Green Deal panorama, with the aim of serving users with electrical and thermal energy using a single plant powered by one or more energy sources. In the waste heat recovery field Organic Rankine Cycle (ORC) power plants are becoming increasingly popular, especially for exploiting medium and low temperature heat sources as a micro-small scale power plant. However, the development and diffusion of this technology is still limited due to the high costs and consequently prototype development and experimental assessment of performance is very poor, especially for non-stationary systems. In this work the modelling and validation of a micro-scale waste heat recovery (WHR) plant coupled with a control system is presented. An ORC plant has been modelled through a map-based model approach for the piston pump and the scroll expander while the pipes and the heat exchangers through a 1D thermo-fluid dynamic approach. A preliminary comparison was made between some numerical quantities of the modelled plant and the same experimental quantities in 61 different operating conditions, showing an average error of 50.1%. The model has been calibrated using a vector optimization technique: two calibration parameters of the heat exchangers were calibrated with a genetic algorithm (MOGA II) by reducing the error of 5 quantities obtained from the model with the respective experimental quantities in 15 different operating conditions. The remaining 46 operating conditions were used to evaluate the calibrated model, showing an average error of 3%. Furthermore, in order to provide for the use of the system coupled to highly variable heat sources, such as the exhaust gases of an internal combustion engine, a control strategy has been designed to perform two tasks: leading the ORC performance where the efficiency is higher, acting on the pump speed through a map-based control, implemented by a look-up table control, and protecting the organic fluid from damage caused by high working temperatures through a bypass control system with a PI control, depending on the proportional and integral gains. In order to verify the control strategy behaviour at different thermal transient inputs, a set of simulations has been run, showing a robust and stable manner preserving the organic fluid properties and limiting the superheated steam at expander inlet.
Design Loads in Small Wind Turbines: a Detailed Comparison Between Pitch and Stall Regulation
Authors: Papi F , Pagamonci L , Bianchini A 
Published: December 2022

Abstract
Small wind turbines (SWTs) have known alternate fortune but can now play a key role in distributed production to foster energy transition. Among the typical features of small machines, the use of stall regulation is a distinctive one, since the ubiquitous variable speed pitch regulation used in utility-scale rotors is hampered by space constraints in small nacelles. This reduced the cost and boosts overall reliability; on the other hand, compromises in the aerodynamic design of the blades must be adopted to ensure smooth power regulation above rated windspeed. This has implications not only on the final Annual Energy Production (AEP) of the rotors, but also on loads. The current study aims at investigating the differences in peak loads between a stall and a pitch regulated SWT. The UNIFI 50kW SRWT, a reference turbine designed by Università degli Studi di Firenze, is used as a case study thanks to the fact that is available both with stall and pitch control options. Differently from most of the studies to date, simulations are carried out for a variety of power production and parked load cases, significant for extreme loading of the rotor and tower of the wind turbine, thus strongly impacting on the design. Results demonstrate how a pitch-regulated machine can ensure a significant reduction of the main maximum loads, thus paving the way for more optimized and cost-effective designs of future SWTs.
Effects of low-grade gas composition on the energy/exergy performance of a polygeneration system (CH
2
HP) based on biomass gasification and ICE
Authors: Caricato A , Carlucci A P , Ficarella A , Previtero F , Strafella L , Prestipino M , Galvagno A , Brusca S 
Published: December 2022

Abstract
Bio-hydrogen from sustainable biomass (i.e. agro-industrial residues) gasification can play a relevant role in the hydrogen economy, providing constant hydrogen from renewable sources. Nowadays, most hydrogen production systems integrate one or more water-gas shift (WGS) units to maximize the hydrogen yield that, however, needs additional syngas treatments, investment and operational costs. Besides, different electricity inputs are needed along the process to power the compression of raw syngas, shifted syngas, and pure hydrogen to the desired pressure. This common process integration with WGS generates a kind of off-gas from the hydrogen separation unit whose composition may or may not be suitable for power production, depending on the operating conditions of the gasification unit. In this regard, this work proposes a different approach in which no WGS reactors are involved and the off-gas is used to generate heat and power to provide the energy input needed by the system. In particular, the authors tested the bio-syngas and the corresponding off-gas in a 4-cylinders, spark ignition natural gas internal combustion engine operated in cogeneration mode with the aim to analyse the effect of removing the hydrogen from the original bio-syngas on mechanical/electric and thermal power, on fuel efficiency and CO2 specific emission.
Pressurised Chemical Looping Combustion (PCLC): Air Reactor design
Authors: Bartocci Pietro , Bidini Gianni , Abad Alberto , Bischi Aldo , Cabello Arturo , Loscertales Margarita de Las Obras , Zampilli Mauro , Massoli Sara , Garlatti Silvia , Fantozzi Francesco 
Published: December 2022

Abstract
Bioenergy combustion with Carbon Capture and Storage (BECCS) is a key technology to achieve carbon negative emissions power generation. This can be achieved by coupling the biofuels combustion with CO2 capture and storage (CCS). The lowest cost for CCS corresponds at the moment to the Chemical Looping Combustion (CLC) process. This can use biofuels which can be gaseous (biomethane, biogas or syngas etc.), liquid (biodiesel, bioethanol, biobutanol and pyrolysis oils etc.) or solids (wood dust, charcoal dust, wood chips, wood pellets etc.) While plant design with gaseous and liquid biofuels would be simpler, plants using solid biofuels and based on two couple fluidisd beds would need the use of a third reactor named carbon stripper. In the specific case if we plan to couple a CLC plant with a turbo expander (to achieve the high efficiencies of a combined cycle power plant) we have to work with pressurized reactors. However, there are some technical barriers to the coupling of a chemical looping combustor with a turbo expander, such as: the operation of the combustor in pressurised conditions; the inventory balance among reactors; elutriated particles reaching the turbo expander. This explaind why there is no commercial plant at the moment capable to do this. The aim of this paper is to present a model for the dimensioning of an air reactor to be coupled to a turbo expander of the power of about 12 MWe. Based on this, the air mass flow can be obtained and the geometric parameters can be calculated, to have an air velocity which is needed to achieve the fast fluidization regime and to ensure a high conversion rate as well as particles and heat exchage among air and fuel reactor.
Vortex Artificial Potential Field for Mobile Robot Path Planning
Authors: Nasuha A , Priambodo A S , Pratama G N P 
Published: December 2022

Abstract
Artificial Potential Field (APF) is one of path planning strategies which offers a relatively low cost on computational. It has been implemented in many real-time applications. Unfortunately, it is quite susceptible to local minima problems. In this paper, we offer a scheme for escaping local minima by using vortex field. Based on the results and simulation, it can be verified that the vortex field prevails to navigate the path while escaping local minima.
FDM Based Custom 3D Printer Development in Robotic Arm Mechanical Prototype Printing
Authors: Prianto E , Herianto  , Herliansyah M K , Pramono H S , Husna A F , Adam R , Raditya A E 
Published: December 2022

Abstract
3D printing is one of the most important tools of Industry 4.0. 3D printing technology has an advantage over traditional manufacturing processes, as it has the ability to convert 3D designs/models into ready-to-use products. The world of education needs to continue to adapt to technological developments. Making a mechanical prototype of a robotic arm is one of the main things to do to develop learning media in an educational environment. The mechanical prototype of the robotic arm can be made using 3D printing, so it will provide real implementation for education. The purpose of this study is to develop a custom 3D Printer learning media which is expected to facilitate the installation process and development of a mechanical prototype of a robotic arm as a form of implementation in the Mechatronics Engineering Education Study Program, FT UNY. This research was carried out based on the ADDIE model, namely Analysis, Design, Development, Implementation and Evaluation. The results of this study are a custom 3D printer based on FDM, both Cartesian and CoreXY types that can be used in learning in the Mechatronic Engineering Education Study Program. The test results show the average value of the measurement error of printing results is less than 2% so that it can be used in the learning process and supports the selected learning content. 3D printers can print robotic arm mechanical components with good results and low tolerances for printing precision.
Development and Evaluation of Portable Microcontroller Training System
Authors: Nahrowi D , Hariyanto D 
Published: December 2022

AbstractThis research aimed to develop a high-portability and multipurpose Microcontroller Trainer by employing Research and Development (R&D) with the ADDIE (Analysis, Des ign, Development, Implementation, Evaluation) model. It focuses on the development s tage (the design aspect) and the testing stage of the trainer’s performance. The results of this study indicate that the developed product of microcontroller trainer can be categorized as “very feasible” to use with a final score of 72. Meanwhile, for the aspect of trainer performance, it is also declared that the developed product is “very feasible” in terms of function and usefulness that can be used as a multipurpose media.
Wireless Engine Diagnostic Tool Based on Internet of Things (IoT) With PiOBD-II Using Raspberry on Honda Jazz VTEC
Authors: Setiyawan A 
Published: December 2022

Abstract
The rate of transportation accidents is still a major challenge in many countries. Many factors can cause transportation accidents, especially problems with the vehicle’s internal system. Fuel Injection-based vehicles have a centralized electronic system through the ECU as control. The outstanding Engine Diagnostic Tool has several weaknesses, including high price, not plug and play, has limited system support. It is necessary to develop a Prototype Engine diagnostic tool that is easy to use, has an overall carrying capacity, and can be easily applied by middle-class vehicle repair shops. So, the researchers researched the Internet of Things (IoT)-Based Wireless Engine Diagnostic Tool prototype using a Raspberry Pi. This study aims to (1) produce a Prototype of the Wireless Engine Diagnostic Tool Based on the Internet of Things (IoT) Using Raspberry Pi and test the functionality of the Prototype Wireless Engine Diagnostic Tool with Raspberry Pi Technology. The research method used is the Research and Development method. The research aims to produce specific products. The product produced and tested for functionality in this research is a Wireless Engine Diagnostic Tool Based on the Internet of Things (IoT) Using Raspberry Pi. The results show that the function runs 100% on the ECT, IAT, TPS, RPM meter, Oxygen Sensor, and Vehicle Speed Sensor tests.
Heterogeneous pHPMA hydrogel promotes neuronal differentiation of bone marrow derived stromal cells in vitro and in vivo
Authors: Rybachuk Oksana , Savytska Natalia , Pinet Éric , Yaminsky Yurii , Medvediev Volodymyr 
Published: December 2022

Abstract
Synthetic hydrogels composed of polymer pore frames are commonly used in medicine, from pharmacologically targeted drug delivery to the creation of bioengineering constructions used in implantation surgery. Among various possible materials, the most common are poly-[N(2-hydroxypropyl)methacrylamide] (pHPMA) derivatives. One of the pHPMA derivatives is biocompatible hydrogel, NeuroGel. Upon contact with nervous tissue, the NeuroGel’s structure can support the chemical and physiological conditions of the tissue necessary for the growth of native cells. Owing to the different pore diameters in the hydrogel, not only macromolecules, but also cells can migrate. This study evaluated the differentiation of bone marrow stromal cells (BMSCs) into neurons, as well as the effectiveness of using this biofabricated system in spinal cord injury in vivo. The hydrogel was populated with BMSCs by injection or rehydration. After cultivation, these fragments (hydrogel + BMSCs) were implanted into the injured rat spinal cord. Fragments were immunostained before implantation and seven months after implantation. During cultivation with the hydrogel, both variants (injection/rehydration) of the BMSCs culture retained their viability and demonstrated a significant number of Ki-67-positive cells, indicating the preservation of their proliferative activity. In hydrogel fragments, BMSCs also maintained their viability during the period of cocultivation and were Ki-67-positive, but in significantly fewer numbers than in the cell culture. In addition, in fragments of hydrogel with grafted BMSCs, both by the injection or rehydration versions, we observed a significant number up to 57%–63.5% of NeuN-positive cells. These results suggest that the heterogeneous pHPMA hydrogel promotes neuronal differentiation of bone marrow-derived stromal cells. Furthermore, these data demonstrate the possible use of NeuroGel implants with grafted BMSCs for implantation into damaged areas of the spinal cord, with subsequent nerve fiber germination, nerve cell regeneration, and damaged segment restoration.
Phasing out coal for 2 °C target requires worldwide replication of most ambitious national plans despite security and fairness concerns
Authors: Vinichenko Vadim , Vetier Marta , Jewell Jessica , Nacke Lola , Cherp Aleh 
Published: December 2022

Abstract
Ending the use of unabated coal power is a key climate change mitigation measure. However, we do not know how fast it is feasible to phase-out coal on the global scale. Historical experience of individual countries indicates feasible coal phase-out rates, but can these be upscaled to the global level and accelerated by deliberate action? To answer this question, we analyse 72 national coal power phase-out pledges and show that these pledges have diffused to more challenging socio-economic contexts and now cover 17% of the global coal power fleet, but their impact on emissions (up to 4.8 Gt CO2 avoided by 2050) remains small compared to what is needed for achieving Paris climate targets. We also show that the ambition of pledges is similar across countries and broadly in line with historical precedents of coal power decline. While some pledges strengthen over time, up to 10% have been weakened by the energy crisis caused by the Russo-Ukrainian war. We construct scenarios of coal power decline based on empirically-grounded assumptions about future diffusion and ambition of coal phase-out policies. We show that under these assumptions unabated coal power generation in 2022–2050 would be between the median generation in 2 °C-consistent IPCC AR6 pathways and the third quartile in 2.5 °C-consistent pathways. More ambitious coal phase-out scenarios require much stronger effort in Asia than in OECD countries, which raises fairness and equity concerns. The majority of the 1.5 °C- and 2 °C-consistent IPCC pathways envision even more unequal distribution of effort and faster coal power decline in India and China than has ever been historically observed in individual countries or pledged by climate leaders.
Environmental Challenges of The Green Economy: Case of Ukraine
Authors: Yermakov Oleksandr , Kostetska Iryna 
Published: December 2022

AbstractThe article analyses the essence of the “green economy.” The historical context of the formation of the concept is considered. The postulates of the theory of “green economy” are studied; the essential postulate appears to be the impossibility of satisfying infinitely growing needs in limited resources. The directions of the “green economy” system are considered. Today, the known characteristics, features, and principles of the “green economy” and its multiplicative and anti-crisis potential are highlighted. The purpose of the study is to prepare proposals for a “green economy” model in Ukraine in the post-war period. An understanding of the essence and description of the goals of “green” technologies is proposed, which involves working not with the consequences but with the causes of environmental problems. The European aspect of the “green economy,” ways of Poland’s transformation, and the state of its implementation in Ukraine are analyzed. As well, normative-legal documents regulating the implementation of changes are given. Poland’s experience in introducing the “green economy” is analyzed. An example of a “green” energy cluster in Konin (Poland) is given. Proposals for implementation have been formed, and the role and prospects of Ukraine’s participation in the strategic development of the “green economy” have been determined.