Real Size Research Articles

A Review on Real-Size Epoxy Cast Resin Insulators for Compact High Voltage Direct Current Gas Insulated Switchgears (GIS) and Gas Insulated Transmission Lines (GIL)—Current Achievements and Envisaged Research and Development

Due to the ever-increasing demand for electricity in the one hand and the environmental constraints to use clean energy on the other hand, the global production of energy from remote renewable sources, particularly from large hydropower plants and offshore wind farms and their connection to the grid are expected to grow significantly in the future. Consequently, the demand to carry this electric power by high voltage direct current (HVDC) technology will increase too. The most suitable HVDC power transmission technology to deliver large amounts of power, exceeding a capacity of 5 GW per bipolar system over long distances with lower losses is by using compact HVDC gas insulated transmission lines (DC GIL) and gas insulated switchgears (DC GIS) with rated voltage (maximum continuous operating voltage) of ±550 kV and 5000 A which are presently under development worldwide. Among the critical challenges for the development of these HVDC gas insulated systems, there are the epoxy cast resin insulators that are used to separate gas compartments also called spacers. Indeed, thorough research studies have been and still being carried out to well understand and clarify the electrical insulation characteristics of HVDC spacers using mainly cylindrical samples and small insulator models, where useful results have been obtained and proposed for implementation in real compact gas insulated systems. However, few practical investigations have been undertaken on real size spacers (product scale) to verify such research outcomes and validate the reliability of the spacers to collect experiences or for commercial use. This paper reviews the current achievements of real size HVDC spacers development. It describes the basic electric field calculation and spacers design, the verification of the insulation performance and validation testing. It gives today’s commercially available compact HVDC GIS/GIL and finally it presents the envisaged future research and development.

Assessment of Friedman Classification by Measuring Actual Tonsil Size During Surgery

Background and Objectives: Adenotonsillar enlargement is a common cause of pediatric illnesses, including obstructive respiratory disease and recurrent airway infection. The current tonsil grading systems evaluate tonsil size, but the correlation with actual tonsillar size in a clinical setting has not been established.Materials and Method: Between May and July of 2018, we recruited 31 children who underwent adenotonsillectomy with no major craniofacial abnormalities. The actual size of the palatine tonsils, the long (L1) and short (S1) axes of the tonsil beyond the anterior pillar, and the real axes (L2 and S2) after tonsil extraction from the fossa were measured during surgery. Adenoid size was determined by measuring the adenoid-nasopharynx (AN) ratio through lateral view x-ray of the neck.Results: Though S1 was related to the Friedman scale (p<0.001), measured real axes were not (L2: p=0.058, S2: p=0.056). Also, adenoid size and AN ratio did not relate statistically to the Friedman scale (p=0.565). One of the measured real tonsil size parameters (S2) was related to AN ratio (p=0.048).Conclusion: For pediatric patients undergoing tonsillectomy and adenoidectomy, the Friedman grading scale based on physical examination may not reflect the actual size of the tonsils. Therefore, for children with obstructive sleep disorder or recurrent tonsillitis, intraoperative measurement of tonsil size can be helpful.

The Network of Dominant Owners of Wind Development in Galicia (Spain) (1995–2017): An Approach Using Power Structure Analysis

This article identifies and characterizes the network of dominant businesses which owned wind farms in Galicia (Spain) from 1995 to 2017. This research contributes to reduce the research gap about identifying the investment groups involved and to appreciate the real size of the wind sector. The novelty of the research lies in identifying the network of real owners of wind farms through the application of Domhoff’s power structure analysis, normally used in the analysis of the power structure of corporations and political institutions. With this method, it is possible to observe how the individual wind farm companies are assessed as well as the matrix company, and/or the principal shareholders to which the farm belongs are identified. The article shows that the installed wind power in Galicia is owned by large energy firms with the participation of international investment funds as well, even though the smaller number of local companies in the sector were given favored status under the existing regulations. This study concludes that although there is no single worldwide model for wind promotion, a network of dominant owners has been formed, and that this network consists of energy companies, investment funds, financial institutions, and construction firms. It can be surmised that if the capital were of mostly Galician origin, this would facilitate a bigger reinvestment of the profits in the region.

Comparative study on prestress loss and flexural performance of rectangular and T beam strengthened by prestressing CFRP plate

Influence of real and small size (laboratory) specimens with different prestress levels on the flexural performance of RC beam has not yet been compared to verify the reliability of experimental research for real applications. In this study, an experiment was designed by casting rectangular (small-scale) and T-section (large-scale) RC beams, which were strengthened by CFRP plates with 0, 20 and 40% prestress levels. The prestress loss and flexural performance was assessed for both scales. The instantaneous and initial 7-day prestress losses of the small-scale specimens were notably higher than those of the large-scale specimens. Thereafter, a four-point bending test was conducted to assess the specimens’ flexural performance. The experimental results showed that the cracking, yield and ultimate moments increased with the prestress level, in which the incremental rate of the ultimate moment of the small-scale specimens was obviously greater than the large-scale specimens. The load–deflection curves of the large-scale specimens suddenly dropped with simultaneous CFRP plate debonding from the plate end, while this phenomenon was not obvious during the small-scale specimen tests. This result indicates that the adhesive bonding benefits the stiffness of the real-size strengthened beams, but this was not observed in the small-size specimen tests.

Performance of Pheromone-Baited Traps to Monitor the Seasonal Abundance of Tortrix Moths in Chestnut Groves

Simple SummaryInvestigations were performed in 2018–2019 in chestnut groves in northern Italy to monitor the seasonal flight activity of Pammene fasciana (L.), Cydia fagiglandana (Zeller), and C. splendana (Hübner) with pheromone-baited traps. Commercially available and experimental pheromone blends were tested. Newly formed chestnut husks and fruits were randomly collected to evaluate damage. Damage was correlated with trap catches. P. fasciana was present in all the sites, while Cydia species were recorded in three of six sites, with differences in abundance related to pheromone blends studied. Several morphologically similar non-target species occurred, highlighting the risk of overestimating catches. Fruit damage did not correlate with trap captures, suggesting that monitoring probably underestimates the true size of the moths’ populations. These data contribute to ascertaining the presence of tortrix moths in northern Italian chestnut groves, and are important for planning specific control measures.(1) Background: Pammene fasciana (L.), Cydia fagiglandana (Zeller), and C. splendana (Hübner) (Lepidoptera: Tortricidae) are considered key moth pests of chestnut in Europe. (2) Methods: Investigations were performed in 2018–2019 in northern Italy. Sticky traps and commercially available pheromones were used for monitoring; moreover, two experimental pheromone blends were tested. All specimens were identified according to male genitalia and molecular analyses. Newly formed chestnut husks and fruits were randomly collected to evaluate the presence of larvae and/or feeding damage, by comparing it to trap catches. (3) Results: P. fasciana was present in all the sites, whereas Cydia species were recorded in three sites of six, with differences in abundance related to pheromone blends studied. Several non-target species, such as Oegoconia novimundi (Busck) and Cydia ilipulana (Walsingham), were present. Data about the seasonal flight activity are provided. (4) Conclusions: This research contributes to ascertaining the presence and abundance of tortrix moths in Italian chestnut groves, and the presence of non-target species highlights the risk of overestimating catches. Fruit damage recorded did not always reflect catches made by pheromone traps, suggesting that monitoring may underestimate the real size of moths’ populations. All of the data acquired are important for planning specific control measures.

Trends of 2019-nCoV in South Asian countries and prediction of the epidemic peaks

A deterministic compartmental model of the corona virus diseases has been introduced to investigate the current outbreak and epidemic peaks of the 2019-nCoV in South Asian countries. We have done details analysis of the above mentioning model and demonstrated its application using publicly reported data. Based on the reported data, we have determined the new infective rate, β = 0.0017, β = 0.00069, β = 0.0011 and β = 0.00047 for India, Pakistan, Bangladesh and Afghanistan, respectively and these values are not found for other countries due to insufficient data. According to present model, the epidemic under the most restrictive measures was observed of peak on around June 29 in Bangladesh with a peak size of 4100 infectious individuals which was closed to real size of 4014. In the same way, the model results also showed that the epidemic peaks were found on around September 16 in India, June 13 in Pakistan and on June 5 in Afghanistan with the peak sizes of 97,500, 6950 and 935, respectively those were closed to the real values. In addition, we have derived a model-implied basic reproduction number for each day of currently infected cases so that the mitigation and defeat strategies can be imposed to control the size of the epidemic.

Ступінь вивченості й сучасний стан гніздових поселень баранця великого Gallinago media на заході України

In the paper, we describe the state of knowledge of the Great Snipe population in Western Ukraine since 19 century. Almost to the middle of the XX century, the state of knowledge about this species and the size of the surveyed territory, especially within the borders of Western Polissia, were considered as insufficient. This was caused by the cryptic behavior of the species, its nocturnal activity, and generally by low population size and ra­rity. We analyzed a significant amount of ornithological resources devoted to observations of Great Snipe in Western Ukraine, which indicate historically low population size and scarcity of distribution of the species in the study area. According to the literature sources, studies of Great snipe were somewhat intensified in the XX century. At the same time, different authors pointed out drainage works in the Polissia area, as a negative factor that drives the decrease in Great Snipe numbers in the area. or even caused complete extinction in some regions. The main range of the species in the area was still localized in the Polissian part of Volyn and Rivne regions, especially in valleys of Prypiat, Turia, Tsyr and Lva rivers. At the end of XX and the beginning of XXI intensive studies of Great Snipe were conducted on the territory of Shatsk National Nature Park, where during 10 years of studies, seasons with an increase of local population were reported, but in general negative tendency was detected and the proposal to include the species into the national red list was published. Our recent studies focused on the species, allowed us to discover new lekking places of Great Snipe. Therefore, the actual information on current numbers and distribution of the species in the region of Western Ukraine is presented. Besides leks, places of occasional observations are also mentioned, which increases the information load of the paper regar­ding the current distribution of the species in the western part of the country. The current population size is estimated as 100 lekking males, based on the total sum from all known leks. We suppose, that the real population size in the region of Western Ukraine can reach 150–200 lekking males.

Emerging algebraic growth trends in SARS-CoV-2 pandemic data

We study the reported data from the SARS-CoV-2 pandemic outbreak in January–May 2020 in 119 countries. We observe that the time series of active cases in individual countries (the difference of the total number of confirmed infections and the sum of the total number of reported deaths and recovered cases) display a strong agreement with algebraic growth and at a later epidemic stage also with a combined algebraic growth with exponential decay. Our results are also formulated in terms of compartment-type mathematical models of epidemics. Within these models the universal scaling characterizing the observed regime in an advanced epidemic stage can be interpreted as an algebraic decay of the relative reproduction number R 0 as T M /t, where T M is a constant and t is the duration of the epidemic outbreak. We show how our findings can be applied to improve predictions of the reported pandemic data and estimate some epidemic parameters. Note that although the model shows a good agreement with the reported data, we do not make any claims about the real size of the pandemic, as the relationship of the observed reported data to the total number of individuals infected in the population is still unknown.

Coupled damage variable based on fracture locus: Prediction of ductile failure in a complex structure

This article focuses on predicting the instant of failure in a real scale component of complex geometry and loading using a ductile damage model calibrated exclusively on small-scale laboratory specimens of relatively simple shape. The ductile behaviour of a strain hardened aluminium alloy AA1050, formed into a thin-walled component, is modelled by a coupled ductile fracture locus model presented in a recent study (Baltic et al., 2020). The component is exposed to high internal pressure and has a safety vent designed for safe pressure handling. The extensive plastic deformation in the safety vent leads to localised ductile failure occurring at a limit load. The pertaining material parameters were calibrated solely from basic ductile fracture experiments in the preceding work (Baltic et al., 2020), where the bottom section of the thin-walled component was machined into notched and shear samples to characterize different states of stress and to construct a well-defined fracture locus. Although the calibrated material model relies on the local fracture strain measurements, it involves a regularization as a function of the length scale defined as a width of the observed localisation band from Digital Image Correlation (DIC) analysis. In the current study the calibration on small-scale specimens is complemented by a large-scale specimen to determine the length scale correction crucial for capturing the correct width of the localisation band in the analysed structure. This is necessary because the failure initiation zones of the calibration specimens and the real size structure, i.e. their gauge lengths where the localisation band appears, vastly differ in size. Finite element (FE) model results are compared to measurements of the deformation of the aluminium component under pressure and maximum load prior to failure. The numerical and experimental results show an excellent agreement and consistent fracture predictions for various mesh discretizations.

Scheduling patient appointment in an infusion center: a mixed integer robust optimization approach.

Infusion centers are experiencing greater demand, resulting in long patient wait times. The duration of chemotherapy treatment sessions often varies, and this uncertainty also contributes to longer patient wait times and to staff overtime, if not managed properly. The impact of such long wait times can be significant for cancer patients due to their physical and emotional vulnerability. In this paper, a mixed integer programming infusion appointment scheduling (IAS) mathematical model is developed based on patient appointment data, obtained from a cancer center of an academic hospital in Central Virginia. This model minimizes the weighted sum of the total wait times of patients, the makespan and the number of beds used through the planning horizon. A mixed integer programming robust slack allocation (RSA) mathematical model is designed to find the optimal patient appointment schedules, considering the fact that infusion time of patients may take longer than expected. Since the models can only handle a small number of patients, a robust scheduling heuristic (RSH) is developed based on the adaptive large neighborhood search (ALNS) to find patient appointments of real size infusion centers. Computational experiments based on real data show the effectiveness of the scheduling models compared to the original scheduling system of the infusion center. Also, both robust approaches (RSA and RSH) are able to find more reliable schedules than their deterministic counterparts when infusion time of patients takes longer than the scheduled infusion time.

Simulating the wet granulation of TiO2 photocatalyst in fluidized bed: Population balance modelling and prediction of coalescence rate

The major focus of this study, the second part of a series, is to simulate the net granulation process of TiO2 powder using 1-D discretized population balance modelling (PBM) and Size-Independent Kernel (SIK) coalescence model. In this, sequential and non-sequential modelling procedures have been used.Tested one-dimensional population balance model and coalescence-only, size-independent kernel provide a good prediction of real TiO2 particle size distributions (PSDs). The coalescence rate is quantified for both modelling procedures and formulation system used. Reduced-order population balance equation (PBE) and quite simple, fully empirical coalescence-only kernel successfully describe and predict real TiO2 PSDs. This paper reveals the meso-scale study of the wet granulation process for the not previously granulated powder system.

Double dissociation between perception and action in children

Previous research has demonstrated a functional dissociation between vision for perception and vision for action. However, the developmental trajectory of this functional dissociation is not well understood. We directly compared the sensitivity of grasping and perceptual estimations within the same experimental design to the real and illusory sizes of objects positioned in the Ponzo illusion display. Two different-sized objects were placed such that the differences between their real sizes and their perceived sizes were pitted against each other. Children aged 5–8 years and adults made perceptual size discriminations and then grasped (action) or estimated (perception) one of the objects based on its perceived size. Consistent with previous results, for the action task, grasping apertures of adults were scaled with the physical differences in the objects’ sizes, even in trials where their overt perceptual decisions were deceived by the illusion. In contrast, perceptual estimations were robustly modulated by the illusion. Interestingly, children outperformed adults in their perceptual discriminations but exhibited adult-like behavior in grasping and in perceptual estimations of the objects, demonstrating a dissociation between perception and action. These results suggest that although the two visual functions are not operating at fully mature levels during childhood, some key mechanisms that support a dissociation between these functions are already in place.

Accurate Measurement of Self-diffusion Coefficient of Nanoparticles in Aqueous Solutions Using a Dynamic Light Scattering

One of the standard methods used to measure the hydrodynamic diameter of nanoparticles is photon correlation spectroscopy, especially dynamic light scattering (DLS). In principle, this technique is to analyze correlation function of the scattered light from the nanoparticles undergoing Brownian motion in solution and to calculate the diffusion coefficient from the correlation function which is converted into the hydrodynamic diameter. However, when using this technique, one needs to pay careful attention to interaction effects (i.e., particle-particle and particle-solvent interactions) on the diffusion coefficient of the particles in solution. If not, then incorrect information can be obtained on the self-diffusion coefficients of nanoparticles. In order to facilitate a strict procedure for obtaining real size of the nanoparticles in solution, we used 20 nm, 50 nm and 100 nm-nominal polystyrene latex (PSL) nanoparticle solutions for DLS measurement. We represented that a rigorous scrutinizing the concentration dependence of the diffusion coefficient of the PSL nanoparticles made it possible to separate the interaction effect from the diffusion phenomena of the PSL nanoparticles suspended in water and to give real size of the PSL nanoparticles.

An improved VOF-DEM model for soil-water interaction with particle size scaling

This study presents an improved VOF-DEM model where the Darcian velocity and a compound variable are treated as unknowns in the pressure-velocity calculation procedure such that the use of interpolated porosity at cell faces is minimised and stability is ensured even if the porosity field is not smooth or even ragged. A higher-order porosity estimation method is also used such that the porosity and interaction force are evaluated correctly when the CFD cell size is of the same order as the DEM particle size. Additionally, a particle size scaling technique is proposed to let the DEM particle size different from the real soil particle size and soil-water interaction forces are the same as when the real soil particle size is used. This is achieved by modifying the calculation of drag force. The solution scheme is verified in two case where analytical solutions exist. Particle size scaling technique is also used and tested in permeability tests and wave interaction with porous structure. Subsequently, the settling and collision of particles in water, dambreak of soil-water mixture and submerged landslides are simulated. With the present improvements and the particle size scaling, the capability of the VOF-DEM is extended in soil-water interaction problems.

Robot scheduling for pod retrieval in a robotic mobile fulfillment system

In order to increase the order picking efficiency, e-commerce retailers have started to implement order picking systems where mobile robots carry inventory pods to pick stations. In pick stations, pickers pick the products from inventory pods and put them in customer bins. In such a robotic mobile fulfillment center, pickers are constantly busy with picking customer orders and avoid non-value adding activities such as walking to reach storage locations. To fulfill customer orders, each robot needs to complete a sequence of missions and each mission includes a set of retrieval requests. We study the operational problem of scheduling a mobile robot fulfilling a set of customer orders from a pick station. The mobile robot needs to bring each pod from a retrieval location to the pick station and return the pod to a storage location. The objective is to minimize the total travel time of the robot which can be considered as a proxy for other objectives such a shorter lead time, higher throughput and less capital investment. We formulate the basic problem as an asymmetric traveling salesman problem. We then extend the model by adding general precedence constraints to give different priorities to customer orders based on their urgency (e.g. same-day, one-day, two-day, and standard orders). We also study a variation of the problem where the pod can be stored in multiple alternative locations. In this case, we model the problem as a generalized asymmetric traveling salesman problem. An adaptive large neighborhood search heuristic is developed to efficiently solve real size instances. The method outperforms the heuristics commonly used in practice.

Photovoltaic modules designed for architectural integration without negative performance consequences

Nowadays, the photovoltaic technology level development makes it the best option for its building integration as energy supplier. Nevertheless, its aesthetic appearance plays a relevant role because architect requirements go beyond the simple installation of solar devices on terraces. In order to fulfill their requirements, the typical white backsheet uses to be replaced by a black one. This simple change leads to a huge PV module performance reduction. In this work, it has been demonstrated that a suitable material selection allows to fabricate photovoltaic modules with a high architectonic integration, but without power reduction with respect to the most commercial solar devices. The former consists in the replacement of the typical glass front cover and the white backsheet by an antireflective glass and a black backsheet respectively. All the study has been developed on real size photovoltaic modules fabricated in an automatic line. The obtained results determine that those modules where black backsheets are used, suffer a power reduction equal to 8.66 W per fabricated module. Nevertheless, when in addition of the black backsheet an antireflective coating glass is implemented, the resulted PV modules present a more aesthetic presence without a detrimental of their power performance when they are compared to the standard PV modules. Additionally, the fabricated solar devices using the proposed configuration successfully overcome the most common aging tests.

Monte Carlo SEM-EDS Nano-Microanalysis Strategy of Historical Mineral Pigments: The Simulation of the Egyptian Blue from Pompeii (Italy) as an Example

A correct determination of the mineral and chemical composition of specimens is of the utmost importance to answer questions regarding the Cultural Heritage field. Because of the preciousness and often very low quantity of sample available, with textures and sizes in the nano-to-micrometric range, scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) is one of the most suited and exploited nano-microanalytical techniques. In these cases, to avoid severe mistakes and quantification errors in SEM-EDS, it is mandatory to consider several effects related to the transport of electrons and X-rays in the material, which in turn are dependent on the SEM-EDS setup. In the present work, a Monte Carlo SEM-EDS nano-microanalytical simulation strategy is proposed and applied to a practical selected case. The Egyptian blue mineral pigment, which is found in Pompeian murals, is used here as an example and model system to show the effects of real size variations (0.1–10 µm), basic geometrical shapes of the pigment (prismatic and spherical) and typical SEM setups, sample holders and substrates. The simulations showed a great—sometimes not intuitive—dependence of the X-ray intensity on the thickness and shape of the samples and SEM-EDS parameters, thereby influencing the analysis and quantification. The critical overview of the results allowed the determination of the correct procedure and technical SEM-EDS parameters and indicated how to apply the Monte Carlo simulation strategy to other Cultural Heritage cases.

Hollar “copia” Leonardo: l’uso della carta lucida per incisioni in scala 1:1

Hollar “copied” Leonardo: The use of ‘carta lucida’ for incisions on a 1:1 scaleHollar “copied” Leonardo for Lord Arundel and, as already demonstrated, in some cases he did it in real size (1:1). In this work process Hollar, following a technique already described by Cennino Cennino in his Book of Art, uses carta lucida: a sheet of paper made transparent through the use of oils that allows him to have an exact copy on the real size of any works of art. An example of this working process can be one drawing attributed to the Follower of Leonardo da Vinci now at the Teylers Museum in Haarlem (inv. A 5). It is an ink drawing on carta lucida with the copy in the real size of a man seen in profile, from the left side of a drawing of Leonardo with a couple of men represented en face (Windsor, RL 12490). The size of the male figure reproduced in Leonardo’s autograph, in the Harlem copy as well as in the Hollar’s engraving is always almost identical. A dimensional match that allows to formulate a new proposal for attribution and to include the Haarlem’s drawing in the corpus of Hollar’s drawings as an example of his workflow.

Heat transport in nanofluid coolant car radiator with louvered fins

Heat transport capacity of conventional coolants for car radiators can be enhanced by adding nano size metal oxide particles. This paper presents a three-dimensional thermo-fluid analysis of real size car radiator with louvered fins and nanofluid based coolants. The base coolant consisting of 60% Ethylene glycol and 40% Water is dispersed with Aluminum oxide, Copper oxide and Zinc oxide nanoparticles. Effects of nanoparticle concentration and flow velocity on heat transfer have been reported. Dependence of thermophysical properties on nanoparticle concentration has also been evaluated. The heat transfer coefficient for coolant was increased by 42.5%, 47.4% and 51.1% on addition of 2% of Aluminum oxide, Zinc oxide and Copper oxide respectively. A Significant linear increase in heat transfer coefficient and Nusselt number was observed with rise in flow Reynolds number. Copper oxide nanoparticles based coolants are found to be more effective. A set of simplified correlations for the Nusselt number is presented.

RETRACTED ARTICLE: Approach towards problem solving on single machine scheduling with unequal release dates and learning effect

This paper concerns the total weighted tardiness on single machine scheduling problem with the concept of learning effect and unequal release dates. A mathematical model is proposed with binary variables and only small size problems can be solved efficiently due to its NP-hardness. Therefore, 4 (four) heuristic methods are developed to solve real size applications including the size of 1000 jobs. The applied heuristics are: genetic, genetic with solution combination, kangaroo and genetic-kangaroo hybrid algorithms. Solutions denote that developed heuristics are efficient for the proposed model. Research of this topic shows that, no study exists on the total weighted tardiness problem with learning effect and unequal release dates together asserted in this paper.