bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Metrics for Fluidic Soft Robot Rotational Actuators
Authors: Rupert Levi , Saunders Benjamin O. , Killpack Marc D.
Published: August 2021

The field of soft robotics is continuing to grow as more researchers see the potential for robots that can safely interact in unmodeled, unstructured, and uncertain environments. However, in order for the design, integration, and control of soft robotic actuators to develop into a full engineering methodology, a set of metrics and standards need to be established. This paper attempts to lay the groundwork for that process by proposing six soft robot actuator metrics that can be used to evaluate and compare characteristics and performance of soft robot actuators. Data from eight different soft robot rotational actuators (five distinct designs) were used to evaluate these soft robot actuator metrics and show their utility. Additionally we provide a simple case study as an example of how these metrics can be used to evaluate soft robot actuators for a designated task. While this paper does not claim to present a comprehensive list of all possible soft robot actuator metrics, the metrics presented can 1) be used to initiate the development and comparison of soft robot actuators in an engineering framework and 2) start a broader discussion of which metrics should be standardized in future soft robot actuator research.
An Open-Source ROS-Gazebo Toolbox for Simulating Robots With Compliant Actuators
Authors: Mengacci Riccardo , Zambella Grazia , Grioli Giorgio , Caporale Danilo , Catalano Manuel G. , Bicchi Antonio
Published: August 2021

To enable the design of planning and control strategies in simulated environments before their direct application to the real robot, exploiting the Sim2Real practice, powerful and realistic dynamic simulation tools have been proposed, e.g., the ROS-Gazebo framework. However, the majority of such simulators do not account for some of the properties of recently developed advanced systems, e.g., dynamic elastic behaviors shown by all those robots that purposely incorporate compliant elements into their actuators, the so-called Articulated Soft Robots ASRs. This paper presents an open-source ROS-Gazebo toolbox for simulating ASRs equipped with the aforementioned types of compliant actuators. To achieve this result, the toolbox consists of two ROS-Gazebo modules: a plugin that implements the custom compliant characteristics of a given actuator and simulates the internal motor dynamics, and a Robotic Operation System (ROS) manager node used to organize and simplify the overall toolbox usage. The toolbox can implement different compliant joint structures to perform realistic and representative simulations of ASRs, also when they interact with the environment. The simulated ASRs can be also used to retrieve information about the physical behavior of the real system from its simulation, and to develop control policies that can be transferred back to the real world, leveraging the Sim2Real practice. To assess the versatility of the proposed plugin, we report simulations of different compliant actuators. Then, to show the reliability of the simulated results, we present experiments executed on two ASRs and compare the performance of the real hardware with the simulations. Finally, to validate the toolbox effectiveness for Sim2Real control design, we learn a control policy in simulation, then feed it to the real system in feed-forward comparing the results.
Fathering Practices in Sweden During the COVID-19: Experiences of Syrian Refugee Fathers
Authors: Wissö Therése , Bäck-Wiklund Margareta
Published: August 2021

This article explores fathering practices among Syrian refugee families in Sweden. Syrian refugees provide an example of people who migrated because of a single major event: the war in Syria. The article examines the impact of the COVID-19 pandemic on fathering practices. The Swedish COVID-19 strategy differed from those adopted in many other countries. Lockdowns were minimal and were not stringently enforced, based on the assumption that individuals would trust the authorities and would take personal responsibility for complying with their guidelines and recommendations. Previous research suggests that migrants and other vulnerable groups were not always well informed about the public policies introduced prior to and during the pandemic. The article draws on empirical data from a wider research project on the family lives of Syrian migrants in Sweden. The authors present their findings from an analysis of eleven ethnographically informed semi-structured interviews, carried out before and during the pandemic, with married fathers who had been living in Sweden for several years. In this article, they focus on three cases representing fathers with varied educational backgrounds and employment histories. These families had in common what are considered by Swedish standards to be overcrowded living conditions; they were forced to accept close family proximity, both physically and emotionally, as they no longer had the supportive networks they were used to in Syria. The three fathers were found to rely more heavily on information provided by the people with whom they were in contact in Sweden than on policies and recommendations from the authorities. These findings confirmed that the previous experiences among refugees of shifting policies regarding migration and integration had lowered their trust in government. They had learnt that they needed to rely on mutual dependency not only between spouses, but also between parents and children.
Effect of Carbon Black Nanoparticle on Neonatal Lymphoid Tissues Depending on the Gestational Period of Exposure in Mice
Authors: Onoda Atsuto , Okamoto Saki , Shimizu Ryuhei , El-Sayed Yasser S. , Watanabe Shiho , Ogawa Shuhei , Abe Ryo , Kamimura Masao , Soga Kohei , Tachibana Ken , Takeda Ken , Umezawa Masakazu
Published: August 2021

Introduction:Particulate air pollution, containing nanoparticles, enhances the risk of pediatric allergic diseases that is potentially associated with disruption of neonatal immune system. Previous studies have revealed that maternal exposure to carbon black nanoparticles (CB-NP) disturbs the development of the lymphoid tissues in newborns. Interestingly, the CB-NP-induced immune profiles were observed to be different depending on the gestational period of exposure. It is important to identify the critical exposure period to prevent toxic effects of nanoparticles on the development of the immune system. Therefore, the present study was aimed to investigate the effect of CB-NP on the development of neonatal lymphoid tissues in mice, depending on the gestational period of exposure.

Methods:Pregnant ICR mice were treated with a suspension of CB-NP (95 μg/kg body weight) by intranasal instillation; the suspension was administered twice during each gestational period as follows: the pre-implantation period (gestational days 4 and 5), organogenesis period (gestational days 8 and 9), and fetal developmental period (gestational days 15 and 16). The spleen and thymus were collected from offspring mice at 1, 3, and 5-days post-partum. Splenocyte and thymocyte phenotypes were examined by flow cytometry. Gene expression in the spleen was examined by quantitative reverse transcription-polymerase chain reaction.

Results:The numbers of total splenocytes and splenic CD3−B220−phenotype (non-T/non-B lymphocytes) in offspring on postnatal day 5 were significantly increased after exposure to CB-NP during the organogenesis period compared with other gestational periods of exposure and control (no exposure). In contrast, expression levels of mRNA associated with chemotaxis and differentiation of immune cells in the spleen were not affected by CB-NP exposure during any gestational period.

Conclusion:The organogenesis period was the most susceptible period to CB-NP exposure with respect to lymphoid tissue development. Moreover, the findings of the present and previous studies suggested that long-term exposure to CB-NP across multiple gestational periods including the organogenesis period, rather than acute exposure only organogenesis period, may more severely affect the development of the immune system.
Effects of Acute Diquat Poisoning on Liver Mitochondrial Apoptosis and Autophagy in Ducks
Authors: Chen Jiaxin , Su Yalin , Lin Renzhao , Lin Fei , Shang Peng , Hussain Riaz , Shi Dayou
Published: August 2021

Diquat (DQ) is an effective herbicide and is widely used in agriculture. Due to persistent and frequent applications, it can enter into aquatic ecosystem and induce toxic effects to exposed aquatic animals. The residues of DQ via food chain accumulate in different tissues of exposed animals including humans and cause adverse toxic effects. Therefore, it is crucial and important to understand the mechanisms of toxic effects of DQ in exposed animals. We used ducks as test specimens to know the effects of acute DQ poisoning on mechanisms of apoptosis and autophagy in liver tissues. Results on comparison of various indexes of visceral organs including histopathological changes, apoptosis, autophagy-related genes, and protein expression indicated the adverse effects of DQ on the liver. The results of our experimental trial showed that DQ induces non-significant toxic effects on pro-apoptotic factors like BAX, BAK1, TNF-α, caspase series, and p53. The results revealed that anti-apoptotic gene Parkin was significantly upregulated, while an upward trend was also observed for Bcl2, suggesting that involvement of the anti-apoptotic factors in ducklings plays an important role in DQ poisoning. Results showed that DQ significantly increased the protein expression level of the autophagy factor Beclin 1 in the liver. Results on key autophagy factors like LC3A, LC3B, and p62 showed an upward trend at gene level, while the protein expression level of both LC3B and p62 reduced that might be associated with process of translation affected by the pro-apoptotic components such as apoptotic protease that inhibits the occurrence of autophagy while initiating cell apoptosis. The above results indicate that DQ can induce cell autophagy and apoptosis and the exposed organism may resist the toxic effects of DQ by increasing anti-apoptotic factors.
Detect Overlapping Community Based on the Combination of Local Expansion and Label Propagation
Authors: Li Xu , Sun Qiming
Published: August 2021

It is a common phenomenon in real life that individuals have diverse member relationships in different social clusters, which is called overlap in the science of network. Detecting overlapping components of the community structure in a network has extensive value in real-life applications. The mainstream algorithms for community detection generally focus on optimization of a global or local static metric. These algorithms are often not good when the community characteristics are diverse. In addition, there is a lot of randomness in the process of the algorithm. We proposed a algorithm combining local expansion and label propagation. In the stage of local expansion, the seed is determined by the node pair with the largest closeness, and the rule of expansion also depends on closeness. Local expansion is just to obtain the center of expected communities instead of final communities, and these immature communities leave only dense regions after pruning according to certain rules. Taking the dense regions as the source makes the label propagation reach stability rapidly in the early propagation so that the final communities are detected more accurately. The experiments in synthetic and real-world networks proved that our algorithm is more effective not only on the whole, but also at the level of the node. In addition, it is stable in the face of different network structures and can maintain high accuracy.
Efficient Construction of the Equation Automaton
Authors: Ouardi Faissal , Lotfi Zineb , Elghadyry Bilal
Published: August 2021

This paper describes a fast algorithm for constructing directly the equation automaton from the well-known Thompson automaton associated with a regular expression. Allauzen and Mohri have presented a unified construction of small automata and gave a construction of the equation automaton with time and space complexity in O(mlogm+m2), where m denotes the number of Thompson automaton transitions. It is based on two classical automata operations, namely epsilon-removal and Hopcroft’s algorithm for deterministic Finite Automata (DFA) minimization. Using the notion of c-continuation, Ziadi et al. presented a fast computation of the equation automaton in O(m2) time complexity. In this paper, we design an output-sensitive algorithm combining advantages of the previous algorithms and show that its computational complexity can be reduced to O(m×|Q≡e|), where |Q≡e| denotes the number of states of the equation automaton, by an epsilon-removal and Bubenzer minimization algorithm of an Acyclic Deterministic Finite Automata (ADFA).
Efficient Forced Response Computations of Acoustical Systems with a State-Space Approach
Authors: Pelling Art J. R. , Sarradj Ennes
Published: August 2021

State-space models have been successfully employed for model order reduction and control purposes in acoustics in the past. However, due to the cubic complexity of the singular value decomposition, which makes up the core of many subspace system identification (SSID) methods, the construction of large scale state-space models from high-dimensional measurement data has been problematic in the past. Recent advances of numerical linear algebra have brought forth computationally efficient randomized rank-revealing matrix factorizations and it has been shown that these factorizations can be used to enhance SSID methods such as the Eigensystem Realization Algorithm (ERA). In this paper, we demonstrate the applicability of the so-called generalized ERA to acoustical systems and high-dimensional input data by means of an example. Furthermore, we introduce a new efficient method of forced response computation that relies on a state-space model in quasi-diagonal form. Numerical experiments reveal that our proposed method is more efficient than previous state-space methods and can even outperform frequency domain convolutions in certain scenarios.
Association of Breed of Sheep or Goats with Somatic Cell Counts and Total Bacterial Counts of Bulk-Tank Milk
Authors: Lianou Daphne T. , Michael Charalambia K. , Vasileiou Natalia G. C. , Liagka Dimitra V. , Mavrogianni Vasia S. , Caroprese Mariangela , Fthenakis George C.
Published: August 2021

The objective was to describe potential associations of somatic cell counts (SCC) and total bacterial counts (TBC) in bulk-tank milk from sheep and goat farms with breeds of these animals in Greece. In total, 325 dairy sheep flocks and 119 dairy goat herds were visited for the collection of milk; the breed of animals in farms was evaluated for a potential association with SCC or TBC. The most frequently seen sheep breeds were the Lacaune (95 flocks) and the Chios (44 flocks). The most frequently seen goat breeds were the indigenous Greek (Capra prisca) (50 herds) and the Murciano-Granadina (13 herds). In a multivariable analysis, the breed and the application of machine-milking in sheep flocks, and the breed and the management system in goat herds emerged as significant factors for increased SCC (>0.75 × 106 cells mL−1) in bulk-tank milk. Further, the month of lactation at sampling in sheep flocks emerged a significant factor for increased TBC (>1500 × 103 cfu mL−1) in bulk-tank milk.
The Role of LncRNAs in Uveal Melanoma
Authors: Milán-Rois Paula , Quan Anan , Slack Frank J. , Somoza Álvaro
Published: August 2021

Uveal melanoma (UM) is an intraocular cancer tumor with high metastatic risk. It is considered a rare disease, but 90% of affected patients die within 15 years. Non-coding elements (ncRNAs) such as long non-coding RNAs (lncRNAs) have a crucial role in cellular homeostasis maintenance, taking part in many critical cellular pathways. Their deregulation, therefore, contributes to the induction of cancer and neurodegenerative and metabolic diseases. In cancer, lncRNAs are implicated in apoptosis evasion, proliferation, invasion, drug resistance, and other roles because they affect tumor suppressor genes and oncogenes. For these reasons, lncRNAs are promising targets in personalized medicine and can be used as biomarkers for diseases including UM.
In Vivo Cell Tracking Using PET: Opportunities and Challenges for Clinical Translation in Oncology
Authors: Lechermann Laura M. , Lau Doreen , Attili Bala , Aloj Luigi , Gallagher Ferdia A.
Published: August 2021

Cell therapy is a rapidly evolving field involving a wide spectrum of therapeutic cells for personalised medicine in cancer. In vivo imaging and tracking of cells can provide useful information for improving the accuracy, efficacy, and safety of cell therapies. This review focuses on radiopharmaceuticals for the non-invasive detection and tracking of therapeutic cells using positron emission tomography (PET). A range of approaches for imaging therapeutic cells is discussed: Direct ex vivo labelling of cells, in vivo indirect labelling of cells by utilising gene reporters, and detection of specific antigens expressed on the target cells using antibody-based radiopharmaceuticals (immuno-PET). This review examines the evaluation of PET imaging methods for therapeutic cell tracking in preclinical cancer models, their role in the translation into patients, first-in-human studies, as well as the translational challenges involved and how they can be overcome.
Relating Entropies of Quantum Channels
Authors: Kurzyk Dariusz , Pawela Łukasz , Puchała Zbigniew
Published: August 2021

In this work, we study two different approaches to defining the entropy of a quantum channel. One of these is based on the von Neumann entropy of the corresponding Choi–Jamiołkowski state. The second one is based on the relative entropy of the output of the extended channel relative to the output of the extended completely depolarizing channel. This entropy then needs to be optimized over all possible input states. Our results first show that the former entropy provides an upper bound on the latter. Next, we show that for unital qubit channels, this bound is saturated. Finally, we conjecture and provide numerical intuitions that the bound can also be saturated for random channels as their dimension tends to infinity.
A Transcriptome Community-and-Module Approach of the Human Mesoconnectome
Authors: Paredes Omar , López Jhonatan B. , Covantes-Osuna César , Ocegueda-Hernández Vladimir , Romo-Vázquez Rebeca , Morales J. Alejandro
Published: August 2021

Graph analysis allows exploring transcriptome compartments such as communities and modules for brain mesostructures. In this work, we proposed a bottom-up model of a gene regulatory network to brain-wise connectome workflow. We estimated the gene communities across all brain regions from the Allen Brain Atlas transcriptome database. We selected the communities method to yield the highest number of functional mesostructures in the network hierarchy organization, which allowed us to identify specific brain cell functions (e.g., neuroplasticity, axonogenesis and dendritogenesis communities). With these communities, we built brain-wise region modules that represent the connectome. Our findings match with previously described anatomical and functional brain circuits, such the default mode network and the default visual network, supporting the notion that the brain dynamics that carry out low- and higher-order functions originate from the modular composition of a GRN complex network
What Is Consciousness? Integrated Information vs. Inference
Authors: Cooke James E.
Published: August 2021

Any successful naturalistic account of consciousness must state what consciousness is, in terms that are compatible with the rest of our naturalistic descriptions of the world. Integrated Information Theory represents a pioneering attempt to do just this. This theory accounts for the core features of consciousness by holding that there is an equivalence between the phenomenal experience associated with a system and its intrinsic causal power. The proposal, however, fails to provide insight into the qualitative character of consciousness and, as a result of its proposed equivalence between consciousness and purely internal dynamics, into the intentional character of conscious perception. In recent years, an alternate group of theories has been proposed that claims consciousness to be equivalent to certain forms of inference. One such theory is the Living Mirror theory, which holds consciousness to be a form of inference performed by all living systems. The proposal of consciousness as inference overcomes the shortcomings of Integrated Information Theory, particularly in the case of conscious perception. A synthesis of these two perspectives can be reached by appreciating that conscious living systems are self-organising in nature. This mode of organization requires them to have a high level of integration. From this perspective, we can understand consciousness as being dependent on a system possessing non-trivial amounts of integrated information while holding that the process of inference performed by the system is the fact of consciousness itself.
Adolescents’ School Burnout: A Comparative Study between Italy and Switzerland
Authors: Gabola Piera , Meylan Nicolas , Hascoët Marine , De Stasio Simona , Fiorilli Caterina
Published: August 2021

This study aimed to analyze and compare students’ school burnout levels in Switzerland and Italy. Previous research has confirmed that female and older students in particular are highly exposed to burnout risk. Nevertheless, few studies have observed this phenomenon through a cross-national comparison. Data on burnout were collected from a sample of 840 adolescents (Italian students = 497; Swiss students = 343) (Mage = 14.98; SD = 1.06; Female = 50%). Burnout was measured using the School Burnout Inventory, and cross-cultural measurement invariance was tested. The results showed that this burnout measure was equivalent between the Italian and Swiss samples. A multivariate analysis of variance was next conducted to investigate the effects of age, gender, and nationality. Results partially confirmed our hypotheses, showing the effect of age but not of gender in explaining burnout differences among students, and between and within-group variance. In particular, the burnout risk was found to be higher in late adolescence (age 16 to 18, Mexhaution = 2.73; Mcynicism = 2.99; MInadequacy = 3.14) than in mid-adolescence (age 13 to 15 Mexhaution = 2.95; Mcynicism = 3.43; MInadequacy = 3.54). Furthermore, Italian adolescents were more exhausted and cynical (Mexhaution = 2.99; Mcynicism = 3.26) than their Swiss peers (Mexhaution = 2.52; Mcynicism = 2.93) when controlling for age and gender. Findings suggest further investigation of the role played by educational and cultural values may be warranted.
Structural and Electronic Properties of Small Perovskite Nanoparticles of the Form ABX3 (A = MA, DEA, FA, GA, B = Pb, Sn, X = Cl, Br, I)
Authors: Garoufalis Christos S. , Galanakis Iosif , Zeng Zaiping , Hayrapetyan David B. , Baskoutas Sotirios
Published: August 2021

Using a combination of first principles and semiempirical calculation, we explore the structural, electronic, and optical properties of a wide range of perovskite (ABX3) nanoparticle of different size and composition. The variations of the BX3 backbone structure considered include all possible combinations of the cations B=Pb,Sn and the anions X=Cl,Br,I, while the interstitial cation A is either methylamonium (MA), or formamidinium (FA), or guanidine amine (GA), or dimethylamine (DEA). Our results indicate that the orientational disorder of the A moieties may affect the structural and electronic properties of the NPs while the optical properties exhibit a clear dependence on the NPs’ size and the types of B cations and X anions, but they are quite insensitive to the type of A cation.
Modeling and Stability Analysis of a Novel Voltage-Oriented Power Coordination Controlled Constant-Frequency AC Microgrid System
Authors: Tang Xiuhui , Zhang Daming , Xiao Dan , Li Miao
Published: August 2021

The conventional AC microgrid power regulation method is achieved using dual undulations of the grid-side voltage and frequency, whose complex variables and processes make the system less efficient and stable. For this problem, this paper proposes a novel two-hierarchical small signal model stability analysis for islanded AC microgrid systems with a designed power regulation algorithm under the constant frequency, mainly aimed at the continual switching microgrids, and considers the future expansion. MATLAB/Simulink simulations and experiments are conducted to validate the feasibility. It is found that there is a strong consistency between the stability of primary and overall systems, and that two key parameters affect the stability properties. Discussing the mutual influence of various parameters, k1 is positively correlated with control intensity and k2 determines the proportion of reactive power distribution in each power generation. Contrasting with the previous complex processes, the unique points of this method are the simplicity of calculation, parameter induction, response testability, strong operability, and system extensibility. The conclusion is that this constant frequency power control is simple, feasible, and stable under several specified conditions.
Characteristics of Refrigerant Boiling Heat Transfer in Rectangular Mini-Channels during Various Flow Orientations
Authors: Piasecka Magdalena , Strąk Kinga
Published: August 2021

This paper reports the results of heat transfer during refrigerant flow in rectangular mini-channels at stationary conditions. The impacts of selected parameters on boiling are discussed, i.e., thermal and flow parameters, dimensions and orientation of the channels. Four refrigerants (FC-72, HFE-649, HFE-7000 and HFE-7100) were used as the working fluid. Research was carried out on the experimental set-up with the test section with a single rectangular mini-channel of 180 mm long and with a group of five parallel mini-channels, each 32 mm long. The temperature of the mini-channel’s heated wall was measured by infrared thermography. Local values of the heat transfer coefficient at the contact surface between the fluid and the plate were calculated using the 1D mathematical method. The results are presented as the relationship between the heat transfer coefficient and the distance along the mini-channel length and boiling curves. Two-phase flow patterns are shown. Moreover, the results concerning various refrigerants and the use of modified heater surfaces are discussed. The main factors influencing the heat transfer process were: mini-channel inclination to the horizontal pane (the highest heat transfer coefficient at 270° and 0°), using modified heater surfaces (especially electroerosion texturing and vibration-assisted laser No. 2 texturing) and working fluids (FC-72 and HFE-7000).
Legal and Political Barriers and Enablers to the Deployment of Marine Renewable Energy
Authors: Apolonia Maria , Fofack-Garcia Rhoda , Noble Donald R. , Hodges Jonathan , Correia da Fonseca Francisco X.
Published: August 2021

Ocean energy is a promising source of clean renewable energy, with clear development targets set by the European Commission. However, the ocean energy sector faces non-technological challenges and opportunities that are frequently overlooked in deployment plans. The present study aimed to provide a critical evaluation of the ocean energy sector’s legal, institutional, and political frameworks with an identification and analysis of both barriers and enabling features for the deployment of ocean energy. In the first stage, a literature review on the current political and regulatory frameworks of a set of European countries was carried out, setting the basis for the main challenges and enabling factors faced by the sector. Secondly, a critical analysis of the main non-technological barriers and enablers was performed, which was supported by questionnaires sent to regulators, technology developers, and test-site managers. This questionnaire allowed us to collect and integrate the views, perceptions, and personal experiences of the main stakeholders of the ocean energy sector in the analysis. The most relevant insights were collected to guide future policy instruments, supports, and consenting measures in a more informed and effective manner and to help accelerate the development of the sector.
Long-Term Natural Gas Consumption Forecasting Based on Analog Method and Fuzzy Decision Tree
Authors: Gaweł Bartłomiej , Paliński Andrzej
Published: August 2021

Classic forecasting methods of natural gas consumption extrapolate trends from the past to subsequent periods of time. The paper presents a different approach that uses analogues to create long-term forecasts of the annual natural gas consumption. The energy intensity (energy consumption per dollar of Gross Domestic Product—GDP) and gas share in energy mix in some countries, usually more developed, are the starting point for forecasts of other countries in the later period. The novelty of the approach arises in the use of cluster analysis to create similar groups of countries and periods based on two indicators: energy intensity of GDP and share of natural gas consumption in the energy mix, and then the use of fuzzy decision trees for classifying countries in different years into clusters based on several other economic indicators. The final long-term forecasts are obtained with the use of fuzzy decision trees by combining the forecasts for different fuzzy sets made by the method of relative chain increments. The forecast accuracy of our method is higher than that of other benchmark methods. The proposed method may be an excellent tool for forecasting long-term territorial natural gas consumption for any administrative unit.
The Impact of Renewable Energy and Economic Complexity on Carbon Emissions in BRICS Countries under the EKC Scheme
Authors: Leitão Nuno Carlos , Balsalobre-Lorente Daniel , Cantos-Cantos José María
Published: August 2021

Economic complexity makes it possible to assess the development of the countries, the relations of innovation, and the differentiation of products. The article considers the links between the hypotheses of the Kuznets environmental curve and economic complexity using panel data for the group of BRICS countries (Brazil, Russia, India, China, and South Africa) from 1990 to 2015. As an econometric strategy, this study considered the panel fully modified least squares (FMOLS), panel dynamic least squares (DOLS), fixed effects (FE), and Panel Quantile Regression. The empirical results showed that economic complexity, income per capita, renewable energy, and carbon dioxide emissions are integrated with the first difference when applying the unit root test. The arguments of Pedroni and Kao cointegration tests were also used. According to these results, the variables used in this research are cointegrated in the long run. The results validated the arguments of the EKC hypothesis, i.e., the income per capita and squared income per capita are positively and negatively correlated with CO2 emissions. Moreover, economic complexity and renewable energy aim to improve environmental damage and climate change.
Numerical Modelling of Heat Transfer in Fine Dispersive Slurry Flow
Authors: Bartosik Artur
Published: August 2021

Slurry flows commonly appear in the transport of minerals from a mine to the processing site or from the deep ocean to the surface level. The process of heat transfer in solid–liquid flow is especially important for the long pipeline distance. The paper is focused on the numerical modelling and simulation of heat transfer in a fine dispersive slurry, which exhibits yield stress and damping of turbulence. The Bingham rheological model and the apparent viscosity concept were applied. The physical model was formulated and then the mathematical model, which constitutes conservative equations based on the time average approach for mass, momentum, and internal energy. The slurry flow in a pipeline is turbulent and fully developed hydrodynamically and thermally. The closure problem was solved by taking into account the Boussinesque hypothesis and a suitable turbulence model, which includes the influence of the yield shear stress on the wall damping function. The objective of the paper is to develop a new correlation of the Nusselt number for turbulent flow of fine dispersive slurry that exhibits yield stress and damping of turbulence. Simulations were performed for turbulent slurry flow, for solid volume concentrations 10%, 20%, 30%, and for water. The mathematical model for heat transfer of the carrier liquid flow has been validated. The study confirmed that the slurry velocity profiles are substantially different from those of the carrier liquid and have a significant effect on the heat transfer process. The highest rate of decrease in the Nusselt number is for low solid concentrations, while for C > 10% the decrease in the Nusselt number is gradual. A new correlation for the Nusselt number is proposed, which includes the Reynolds and Prandtl numbers, the dimensionless yield shear stress, and solid concentration. The new Nusselt number is in good agreement with the numerical predictions and the highest relative error was obtained for C = 10% and Nu = 44.3 and is equal to −12%. Results of the simulations are discussed. Conclusions and recommendations for further research are formulated.
Multi-Period Fast Robust Optimization for Partial Distributed Generators (DGs) Providing Ancillary Services
Authors: Zhang Jian , Cui Mingjian , He Yigang
Published: August 2021

Distributed generators providing auxiliary service are an important means of guaranteeing the safe and economic operation of a distribution system. In this paper, considering an energy storage system (ESS), switchable capacitor reactor (SCR), step voltage regulator (SVR), and a static VAR compensator (SVC), a two-stage multi-period hybrid integer second-order cone programming (SOCP) robust model with partial DGs providing auxiliary service is developed. If the conic relaxation is not exact, a sequential SOCP is formulated using convex–concave procedure (CCP) and cuts, which can be quickly solved. Moreover, the exact solution of the original problem can be recovered. Furthermore, in view of the shortcomings of the large computer storage capacity and slow computational rate for the column and constraint generation (CCG) method, a method direct iteratively solving the master and sub-problem is proposed. Increases to variables and constraints to solve the master problem are not needed. For the sub-problem, only the model of each single time period needs to be solved. Then, their objective function values are accumulated, and the worst scenarios of each time period are concatenated. As an outcome, a large amount of storage memory is saved and the computational efficiency is greatly enhanced. The capability of the proposed method is validated with three simulation cases.
Development of a Novel Gasoline Particulate Filter Loading Method Using a Burner Bench
Authors: Dorscheidt Frank , Pischinger Stefan , Claßen Johannes , Sterlepper Stefan , Krysmon Sascha , Görgen Michael , Nijs Martin , Straszak Pawel , Abdelkader Abdelrahman Mahfouz
Published: August 2021

In view of the deliberations on new Euro 7 emission standards to be introduced by 2025, original equipment manufacturers (OEMs) are already hard at work to further minimise the pollutant emissions of their vehicles. A particular challenge in this context will be compliance with new particulate number (PN) limits. It is expected that these will be tightened significantly, especially by including particulates down to 10 nm. This will lead to a substantially increased effort in the calibration of gasoline particulate filter (GPF) control systems. Therefore, it is of great interest to implement advanced methods that enable shortened and at the same time more accurate GPF calibration techniques. In this context, this study presents an innovative GPF calibration procedure that can enable a uniquely efficient development process. In doing so, some calibration work packages involving GPF soot loading and regeneration are transferred to a modern burner test bench. This approach can minimise the costly and time-consuming use of engine test benches for GPF calibration tasks. Accurate characterisation of the particulate emissions produced after a cold start by the target engine in terms of size distribution, morphology, and the following exhaust gas backpressure and burn-off rates of the soot inside the GPF provides the basis for a precise reproduction and validation process on the burner test bench. The burner test bench presented enables the generation of particulates with a geometric mean diameter (GMD) of 35 nm, exactly as they were measured in the exhaust gas of the engine. The elemental composition of the burner particulates also shows strong similarities to the particulates produced by the gasoline engine, which is further confirmed by matching burn-off rates. Furthermore, the exhaust backpressure behaviour can accurately be reproduced over the entire loading range of the GPF. By shifting GPF-related calibration tasks to the burner test bench, total filter loading times can be reduced by up to 93%.
Fluid Dynamics of Thrust Vectorable Submerged Nozzle
Authors: Denisikhin Sergey , Emelyanov Vladislav , Volkov Konstantin
Published: August 2021

A numerical simulation of the gas-dynamic processes in the thrust vectorable nozzle of the solid rocket motor is considered. Construction of a geometric model and a generation of computational mesh, and reconstruction of model and mesh at each time step are discussed. Calculations of the flowfield of combustion products in the pre-nozzle chamber and nozzle block are carried out for various angles of nozzle rotation. The distributions of the gas dynamic quantities in the pre-nozzle volume corresponding to the outflow of the combustion products from the cylindrical channel and star-shaped channel are compared, as well as the solutions of the problem obtained with quasi-stationary and unsteady formulations. The effects of the channel shape on the distribution of flow quantities and formation of a vortical flow structure in the nozzle block are discussed.
Three-Month Results of Brolucizumab Intravitreal Therapy in Patients with Wet Age-Related Macular Degeneration
Authors: Michalska-Małecka Katarzyna , Śpiewak Dorota , Luksa Dorota
Published: August 2021

The purpose of the study was to evaluate changes in best corrected visual acuity, central retinal thickness, area and flow in the neovascular membrane and to compare therapeutic outcomes from baseline in patients who received three doses of Beovu (brolucizumab) at three-month follow-up. Material and methods: A prospective observational study conducted at the Prof. K. Gibiński University Clinical Center of the Medical University of Silesia in Katowice. Eight patients with exudative form of age-related macular degeneration (AMD) were observed. Results: The mean best corrected visual acuity (BCVA) outcome increased with each subsequent visit. The mean central retinal thickness (CRT) result also improved (decreased) with each subsequent visit, except for the last measurement. A statistically significant change in neovascular membrane area was observed after the first injection. In further treatment, the membrane area underwent changes that were not statistically significant. A statistically significant change in neovascular membrane flow was demonstrated after the first and second injections. Discussion: Our study confirmed the efficacy of brolucizumab in the treatment of patients with exudative AMD in terms of improvements in best corrected visual acuity (BCVA), central retinal thickness (CRT), neovascular membrane area, and neovascular membrane flow area.
Integrated Assessment of Affinity to Chemical Fractions and Environmental Pollution with Heavy Metals: A New Approach Based on Sequential Extraction Results
Authors: Vodyanitskii Yuri , Vlasov Dmitry
Published: August 2021

To assess the affinity degree of heavy metals (HMs) to geochemical phases, many indices with several limitations are used. Thus, this study aims to develop a new complex index for assessing contamination level and affinity to chemical fractions in various solid environmental media. For this, a new integrated approach using the chemical affinity index (CAF) is proposed. Comparison of CAF with %F on the literature examples on fractionation of HMs from soils, bottom sediments, atmospheric PM10, and various particle size fractions of road dust proved a less significant role of the residual HMs fraction and a greater contribution of the rest of the chemical fractions in the pollution of all studied environments. This fact is due to the normalization relative to the global geochemical reference standard, calculations of contribution of an individual element to the total pollution by all studied HMs, and contribution of the particular chemical fraction to the total HMs content taken into account in CAF. The CAF index also shows a more significant role in pollution and chemical affinity of mobile and potentially mobile forms of HMs. The strong point of CAF is the stability of the obtained HM series according to the degree of chemical affinity and contamination. Future empirical studies are necessary for the more precise assessment of CAF taking into account the spatial distribution of HMs content, geographic conditions, geochemical factors, the intensity of anthropogenic impact, environmental parameters (temperature, humidity, precipitation, pH value, the content of organic matter, electrical conductivity, particle size distribution, etc.). The combined use of CAF along with other indices allows a more detailed assessment of the strength of HMs binding to chemical phases, which is crucial for understanding the HMs’ fate in the environment.
A Call to Clarify the Intensity and Classification of Standing Behavior
Authors: Kowalsky Robert J. , Stoner Lee , Faghy Mark A. , Barone Gibbs Bethany
Published: August 2021

Public health guidelines for physical activity now include recommendations to break up prolonged sitting with light-intensity activities. Concurrently, interventions to increase standing have emerged, especially within the workplace in the form of sit–stand or standing workstations. Moreover, in short-duration studies, breaking up prolonged sitting with standing has been associated improved cardiometabolic outcomes. Publicly available estimates of the intensity of standing range from 1.5 to 2.3 metabolic equivalents (METs), neatly classifying standing as a light-intensity activity (>1.5 to <3.0 METs). Further delineation between ‘active’ and ‘passive’ standing has been proposed, with corresponding METs of >2.0 METs and ≤2.0 METs, respectively. However, this study reviews data suggesting that some standing (e.g., while performing deskwork) is substantially below the minimum light intensity activity threshold of 1.5 METs. These data bring into question whether standing should be universally classified as a light-intensity behavior. The objectives of this study are to (i) highlight discrepancies in classifying standing behavior in the human movement spectrum continuum, and (ii) to propose a realignment of the ‘active’ vs. ‘passive’ standing threshold to match the light intensity threshold to help provide a clearer research framework and subsequent public health messaging for the expected health benefits from standing.
Relationship between Physical Activity, Sedentary Behavior, and Anthropometric Measurements among Saudi Female Adolescents: A Cross-Sectional Study
Authors: Ahmad Bahathig Abeer , Abu Saad Hazizi , Md Yusop Nor Baizura , Mohd Shukri Nurul Husna , El-Din Maha M. Essam
Published: August 2021

Overweight and obesity are becoming increasingly prevalent among children and adolescents in Saudi Arabia and are an emerging cause of non-communicable diseases (NCDs). Lifestyle factors, such as insufficient levels of physical activity and sedentary behaviors, are responsible for the increased prevalence of NCDs. This study aimed to determine the association between physical activity levels, sedentary behaviors, and anthropometric measurements in Saudi female adolescents. A cross-sectional study was carried out among 399 healthy female adolescent students aged 13–14 years in Arar, Saudi Arabia. The participants were randomly selected from different schools and their anthropometric measurements were determined. The Physical Activity Questionnaire for Older Children (PAQ-C) and the Adolescent Sedentary Activity Questionnaire (ASAQ) were used to assess their physical activity levels and sedentary behaviors, and an analysis was conducted using IBM SPSS software version 25. A multiple linear regression model was used to determine the association between the variables. The majority of the participants had a normal body mass index (BMI; 79.4%) and waist circumference (WC; 62.4%). A total of 74.4% had waist to height ratio (WHtR) < 0.5. About 92.7% of the participants were not meeting PA recommendations of 60 min of moderate to vigorous physical activity daily. The overall mean time spent on sedentary activities was high on both weekdays and weekend days at 357.64 ± 86.29 and 470.51 ± 147.64 min/day, respectively. Moreover, anthropometric measurement (BMI) was positively associated with age and negatively associated with sedentary behavior on weekends, while WHtR was positively associated with age. The multiple linear regression analysis also showed that age and sedentary behavior significantly predicted BMI among the study participants (F (2, 396) = 4.346, p < 0.014) and age was the only significant predictor of WHtR (F (1, 397) = 16.191, p ≤ 0.001). This study revealed that most of the female Saudi adolescents undertook low levels of activity and high levels of sedentary behaviors. Sedentary behaviors were significantly associated with their BMI. Accordingly, an intervention program on healthy lifestyles is important to improve Saudi female adolescents’ lifestyles.
Understanding the Impacts of Novel Coronavirus Outbreaks on People Who Use Drugs: A Systematic Review to Inform Practice and Drug Policy Responses to COVID-19
Authors: Munro Alison , Booth Hazel , Gray Nicola M. , Love Joan , Mohan Andrea R. M. , Tang Jason , MacGillivray Steve
Published: August 2021

People who use drugs (PWUD) experience many social and health harms and are considered at greater risk of acquiring COVID-19. Little research has examined the impact of coronaviruses either on PWUD, or on services targeted to PWUD. We report the findings of a systematic review of empirical evidence from studies which have examined the impact of coronaviruses (Severe Acute Respiratory Syndrome (SARS-CoV-1) and Middle Eastern Respiratory Syndrome (MERS-CoV) and COVID-19) on PWUD or on service responses to them. Five databases were searched (MEDLINE, PsycINFO, CINAHL, ASSIA and EMBASE) as well as COVID-19 specific databases. Inclusion criteria were studies reporting any impact of SARS, MERS or COVID-19 or any service responses to those, published between January 2000 and October 2020. Weight of Evidence judgements and quality assessment were undertaken. In total, 27 primary studies were included and grouped by seven main themes: treatment/recovery services; emergency medical settings; low-threshold services; prison setting, PWUD/substance use disorder (SUD) diagnosis; people with SUD and HIV; ‘Sexual minority’ men. Overall, research in the area was scant, and of average/poor quality. More robust research is required to inform on-going and future responses to coronavirus epidemics for PWUD.