bluuebunny/crossref_metadata_2025 huggingface dataset:
The relevance of local magnetic records when using extreme space weather events as benchmarks
Authors: Saiz Elena , Cid Consuelo , Guerrero Antonio
Published: May 2021

Space weather indices introduced for scientific purposes are commonly used to quantify operational nowcast of the geospace state during extreme space weather events. Some indices, such as the Disturbance storm time (Dst) index, have been applied to situations for which they are not originally intended. This raises a question about suitability as a space weather benchmark. In analysing historical records for different magnetometers at low- and mid-latitude, we find periods with longitudinal asymmetry in magnetic response that suggest important signals from individual magnetometers are being averaged out of the Dst record. This asymmetry develops as a double spike in the H-component: one negative in the observatories in the day sector and one positive in the observatories in the night sector. These spikes develop in short-time (about 2 h) and pose a potential hazardous effect for users affected by space weather. The results from historical events have been reinforced with the systematic study of magnetic records during extreme events (Dst ≤ −200 nT and AL ≤ −2000 nT) in the period 1998–2017 from six magnetic observatories at about 40° magnetic latitude. Moreover, we show that the largest asymmetries take place during the early main phase and are recorded in narrow local time sectors. An important outcome of these results is that space weather benchmarks should be based on local records instead of the commonly used global indices. This action improves two important aspects of space weather: the assessment of historical extreme events and that of the needs of users.
Allergien bei Tieren phytotherapeutisch therapieren
Authors: Thoonsen Yvonne
Published: May 2021

Allergien gehen mit einer Schädigung der epidermalen Hautbarriere einher. Eine zusätzliche Versorgung mit essenziellen Fettsäuren (enthalten in pflanzlichen Ölen), Ceramiden (in Form von Linolsäure als deren Vorstufe) und Avocadin® (in der Regel topisch angewendet) hilft, sie zu regenerieren. Eine tabellarische Übersicht informiert über weitere Phytotherapeutika zur Behandlung vorgeschädigter Haut.
Metallic Implants in MRI – Hazards and Imaging Artifacts
Authors: Peschke Eva , Ulloa Patricia , Jansen Olav , Hoevener Jan-Bernd
Published: May 2021

Background Magnetic resonance imaging (MRI) is an examination method for noninvasive soft tissue imaging without the use of ionizing radiation. Metallic implants, however, may pose a risk for the patient and often result in imaging artifacts. Due to the increasing number of implants, reducing these artifacts has become an important goal. In this review, we describe the risks associated with implants and provide the background on how metal-induced artifacts are formed. We review the literature on methods on how to reduce artifacts and summarize our findings.

Method The literature was searched using PubMed and the keywords “MRI metal artifact reduction”, “metallic implants” and “MRI artefacts/artifacts”.

Results and Conclusion The MRI compatibility of implants has to be evaluated individually. To reduce artifacts, two general approaches were found: a) parameter optimization in standard sequences (echo time, slice thickness, bandwidth) and b) specialized sequences, such as VAT, OMAR, WARP, SEMAC and MAVRIC. These methods reduced artifacts and improved image quality, albeit at the cost of a (sometimes significantly) prolonged scan time. New developments in accelerated imaging will likely shorten the scan time of these methods significantly, such that routine use may become feasible.

Key Points: 

Citation Format
Posterior Mediastinal and Cutaneous Back Hemangiomas in Infants: A New Association
Authors: AbouZeid Amr AbdelHamid , Mohammad Shaimaa Abdelsattar , Aly Heba Gomaa , Ragab Iman Ahmed
Published: May 2021

Infantile hemangiomas (IHs) are common vascular tumors. In most cases, a benign course with favorable outcome can be anticipated. IH typically present as cutaneous lesions either with a localized or diffuse segmental distribution. Segmental hemangiomas in the face may be associated with brain and cardiac anomalies (PHACES syndrome), whereas airway involvement has been reported to be associated with hemangiomas in the “beard” area. Multiple cutaneous hemangiomas may be associated with visceral hemangiomas (commonly in the liver).

In this report, we present a new association where deep paravertebral hemangiomatous lesions were observed to be associated with cutaneous back hemangiomas in two consecutive cases.
Decomposing the performance metrics of coconut cultivation in the South Indian States
Authors: Kappil Shine Raju , Aneja Ranjan , Rani Poonam
Published: May 2021

Coconut (Cocos nucifera) is extensively cultivated and used as a staple ingredient in Indian cuisines, especially in the South Indian cuisines. In India, other than edible purposes, coconut is widely used in religious practices and, it is considered as symbol of prosperity. Despite these facts, several upturns and downturns occurring in the growth trends of coconut in recent periods irrespective of geographical differences. This study attempts to decipher the growth trends in the area, the production and yield of coconut in major coconut producing states in India from 2000–2001 to 2017–2018. Kerala, Tamil Nadu and Karnataka are the states in India where coconut palms are extensively cultivated and produced in large quantities. These states together contribute to approximately 84 per cent of the total area for cultivation of coconut and account for over 87 per cent of total production in the country. We analyse the growth trends in coconut cultivation using appropriate growth equations to estimate the growth rates and instabilities in growth trends. Besides, we use decomposition analysis to find the role of area, price, yield and crop mix effects on coconut production. The results reveal that Karnataka secured high growth in coconut production and its productivity and recorded better acceleration but fluctuated heavily between the phases of years under investigation. It shows that the price effect and yield effect play a crucial role in the total change of coconut production among the selected states. Based on the results, we recommend the local governments and other dedicated authorities to ensure that coconut growers have better access to modern technology, quality inputs, marketing and credit facilities following local necessity. Eventually, these measures can attract and encourage many new farmers into coconut cultivation and thereby achieving better advances in coconut farming.
Cross Sections for Electron Collisions with H2O
Authors: Song Mi-Young , Cho Hyuck , Karwasz Grzegorz P. , Kokoouline Viatcheslav , Nakamura Yoshiharu , Tennyson Jonathan , Faure Alexandre , Mason Nigel J. , Itikawa Yukikazu
Published: May 2021

Electron collision cross section data for the water molecule are compiled from the literature. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, electronic excitation, dissociation, ionization, and dissociative attachment. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed up to the end of 2019.
Spatially resolved single-shot absorption spectroscopy with x-ray free electron laser pulse
Authors: Inubushi Yuichi , Yabuuchi Toshinori , Miyanishi Kohei , Sueda Keiichi , Togashi Tadashi , Kubota Yuya , Tono Kensuke , Yabashi Makina
Published: May 2021

A new method of spatially resolved single-shot absorption spectroscopy for an x-ray free electron laser (XFEL) pulse has been developed by using a dispersive spectrometer and an elliptical mirror to enhance the spatial resolution. As a demonstration, we performed x-ray absorption near-edge structure measurement of Cu with a pump–probe scheme combining an XFEL pulse and a high-power femtosecond laser pulse. In the experiment, changes of an absorption spectrum in a plasma generated with a laser shot were successfully observed. The method will be a powerful tool for experiments requiring a spatial resolution and/or a single-shot measurement, such as high energy density science using a high-power laser pulse.
Observation of gain operation mode in Ge:B BIB THz detector
Authors: Pan Changyi , Yin Ziwei , Mou Hao , Kang Tingting , Deng Huiyong , Wu Huizhen , Dai Ning
Published: May 2021

Blocked impurity band (BIB) detectors play an important role in astronomical detection from the mid-infrared to THz region. We demonstrated the field dependence of the photoresponse in BIB detectors using both experimental results and theoretical calculations. It was found that there is a gain operation region between the saturation voltage of the photocurrent and the breakdown voltage of the dark current. The photoconduction gain in the gain operation region is several orders of magnitude larger than that in the other voltage range. Considering the field-assisted thermal ionization process and the photon-assisted impact ionization process, the gain operation mode can be well explained. Utilizing the gain operation mode, Ge:B BIB detectors can even detect the objects with a temperature as low as 10 K. We provide a theoretical basis to optimize BIB detectors and further improve their detection performance.
Terahertz Faraday rotation of aluminum-substituted barium hexaferrite
Authors: Grebenchukov A. N. , Ivanova V. I. , Kropotov G. I. , Khodzitsky M. K.
Published: May 2021

Faraday rotation effect of magnetized hexagonal ferrites BaAlxFe12−xO19 (x=1.4,2.0) with a varied density in the frequency range of 0.1–1.0 THz was investigated using terahertz (THz) time-domain spectroscopy. Broadband polarization rotation up to 20° for 1-mm thick hexaferrite was demonstrated at room temperature. It was shown that the value of Faraday rotation can be effectively controlled by varying hexaferrite sample density as well as Al concentration. From the experimental data, the full permittivity tensor characterization of different hexaferrite samples was extracted to double-check the calculation of Faraday rotation. The obtained results demonstrate prospects for the utilization of BaAl1.4Fe10.6O19 hexaferrite with the highest density as a broadband self-biased complete THz isolator with moderate insertion losses below 5 cm–1 in the range up to 0.4 THz.
High temperature spin-driven multiferroicity in ludwigite chromocuprate Cu2CrBO5
Authors: Damay Françoise , Sottmann Jonas , Fauth François , Suard Emmanuelle , Maignan Antoine , Martin Christine
Published: May 2021

We report spin-driven multiferroicity above 100 K in the ludwigite Cu(II) oxyborate Cu2CrBO5. Spontaneous polarization, which reaches 35 μC m−2 at 5 K, appears below 120 K, concomitantly with an incommensurate antiferromagnetic order and complex magnetodielectric effects. In magnetically induced ferroelectrics, multiferroicity usually appears at low temperature because of the competing magnetic exchanges needed to stabilize a magnetic spiral. The remarkably high transition temperature observed in Cu2CrBO5 originates from the presence of strong Cu–O–Cu magnetic super-exchange interactions, which are not weakened by Cu/Cr cationic disorder. Our result provides an important contribution to the search for high temperature spin-driven multiferroics among low-dimensional cuprates.
Rigid germs of finite morphisms of smooth surfaces and rational Belyi pairs
Authors: Kulikov Vik. S.
Published: May 2021

In the paper “On rigid germs of finite morphisms of smooth surfaces” (Sb. Math., 211:10 (2020), 1354–1381), we defined a map

from the set

of equivalence classes of rigid germs of finite morphisms branched in germs of curves having

singularity types onto the set

of rational Belyi pairs

, considered up to the action of

. In this article the inverse images of this map are investigated in terms of monodromies of Belyi pairs.

Bibliography: 7 titles.
Neural indicators of articulator-specific sensorimotor influences on infant speech perception
Authors: Choi Dawoon , Dehaene-Lambertz Ghislaine , Peña Marcela , Werker Janet F.
Published: May 2021

Significance

In the adult brain, multimodal speech perception that interfaces with a bidirectional interaction of perception and production speech systems is increasingly accepted. Speech perception in infancy is already highly multisensory, suggesting an early emerging representation for speech across sensory modalities. We provide electrophysiological evidence for sensorimotor influences on auditory speech discrimination responses in 3-mo-old infants who are several months away from producing canonical babbling. Auditorily, infants discriminated both contrasts tested. However, a tongue-tip articulatory inhibition diminished the /ɗa/-/ɖa/ discrimination (both phones involve the tongue-tip movement as a place of articulation), whereas accentuating the /ba/-/ɗa/ discrimination (different articulators involved in the articulation of the two phones). These findings suggest that prebabbling infants’ speech perception is more robustly multisensory than previously considered.
Hydrocotyle ranunculoides (floating pennywort).
Authors: Djeddour Djami
Published: May 2021

H. ranunculoides is a perennial, aquatic plant native to the Americas. It was introduced outside of its native range through the aquatic nursery trade and has since naturalized in many countries around the world. Like many aquatic weeds, H. ranunculoides possesses a number of characteristics which contributes to its invasiveness: high growth rates, adaptability to prevailing nutrient conditions, very effective vegetative propagation, plasticity in growth response, overwintering to avoid low temperature stress, resistance to herbivory, resistance to chemical control, and absence of specific pests and diseases in introduced environments. Its rapid growth means that H. ranunculoides can produce dense, interwoven floating mats across slow-flowing waters. These mats restrict the light available for submerged macrophytes, decreases oxygen levels and therefore decrease the overall biodiversity of an area. It can also increase the risk of flooding and block channels. H. ranunuloides is considered a serious invader in Belgium, the Netherlands, and the UK in particular and was added to the EPPO alert list in 2004 (EPPO, 2004) and Schedule 9 of the Wildlife and Countryside Act in the UK. It is also banned from sale in the Netherlands. It has spread into water bodies in a number of other European countries including France, Belgium, Germany and Italy. In 2016, the European Commission's Implementing Regulation (2016/1141) was published, which includes H. ranunculoides among the list of 14 invasive alien plant species of Union concern.
Solanum elaeagnifolium (silverleaf nightshade).
Authors: Datiles Marianne Jennifer , Acevedo-Rodríguez Pedro
Published: May 2021

S. elaeagnifolium is a deep-rooted summer-growing perennial plant, native to the Americas, but now widely naturalized beyond its native range in extra-tropical regions. It is considered a tenacious weed in many arid to semi-arid places including India, Australia, South Africa, the Pacific Islands, and the USA (Holm et al., 1979; Wagner et al., 1999; Randall, 2012; USDA-ARS, 2014). It is known to be invasive in Cuba (Oviedo-Prieto et al., 2012) and Hawaii (PIER, 2014), a principal weed in India (Holm et al., 1979), and an agricultural weed in Java (Randall, 2012). It has been declared a noxious weed in the U.S. states of Arkansas, California, Idaho, Nevada, and Washington, and an "A" designated weed for quarantine in Oregon and Washington (USDA-NRCS, 2014). The species competes with crops, interferes with livestock, acts as a host for insects and plant diseases, and spreads by forming dense colonies from its extensive root system as well as by propagation of seeds (Boyd et al., 1984; Wagner et al., 1999; EPPO, 2007; PIER, 2014). The species is difficult to control without chemicals (UC Davis Weed Research and Information Center, 2013) and it is essential to keep it out of uncontaminated areas (EPPO, 2007). The species is known to be toxic to cattle, causing damage to intestinal tract and nervous systems and, in severe cases, can cause hallucinations, paralysis, and death (Mas and Lugo-Torres, 2013).
The atypical antipsychotic risperidone targets hypothalamic melanocortin 4 receptors to cause weight gain
Authors: Li Li , Yoo Eun-Seon , Li Xiujuan , Wyler Steven C. , Chen Xiameng , Wan Rong , Arnold Amanda G. , Birnbaum Shari G. , Jia Lin , Sohn Jong-Woo , Liu Chen
Published: May 2021

Atypical antipsychotics such as risperidone cause drug-induced metabolic syndrome. However, the underlying mechanisms remain largely unknown. Here, we report a new mouse model that reliably reproduces risperidone-induced weight gain, adiposity, and glucose intolerance. We found that risperidone treatment acutely altered energy balance in C57BL/6 mice and that hyperphagia accounted for most of the weight gain. Transcriptomic analyses in the hypothalamus of risperidone-fed mice revealed that risperidone treatment reduced the expression of Mc4r. Furthermore, Mc4r in Sim1 neurons was necessary for risperidone-induced hyperphagia and weight gain. Moreover, we found that the same pathway underlies the obesogenic effect of olanzapine—another commonly prescribed antipsychotic drug. Remarkably, whole-cell patch-clamp recording demonstrated that risperidone acutely inhibited the activity of hypothalamic Mc4r neurons via the opening of a postsynaptic potassium conductance. Finally, we showed that treatment with setmelanotide, an MC4R-specific agonist, mitigated hyperphagia and obesity in both risperidone- and olanzapine-fed mice.
Ferroptosis in infection, inflammation, and immunity
Authors: Chen Xin , Kang Rui , Kroemer Guido , Tang Daolin
Published: May 2021

Ferroptosis is a type of regulated necrosis that is triggered by a combination of iron toxicity, lipid peroxidation, and plasma membrane damage. The upstream inducers of ferroptosis can be divided into two categories (biological versus chemical) and activate two major pathways (the extrinsic/transporter versus the intrinsic/enzymatic pathways). Excessive or deficient ferroptotic cell death is implicated in a growing list of physiological and pathophysiological processes, coupled to a dysregulated immune response. This review focuses on new discoveries related to how ferroptotic cells and their spilled contents shape innate and adaptive immunity in health and disease. Understanding the immunological characteristics and activity of ferroptotic death not only illuminates an intersection between cell death and immunity but may also lead to the development of novel treatment approaches for immunopathological diseases.
Huntington’s disease skeletal muscle has altered T-tubules
Authors: Khan Muhammad S. , Shaw Robin M.
Published: May 2021

Romer et al. explored T-tubules in skeletal muscle.
Manipulating metal–insulator transitions of VO2 films via embedding Ag nanonet arrays*
Authors: Zhou Zhangyang , Yang Jia , Liu Yi , Gao Zhipeng , Cao Linhong , Fang Leiming , He Hongliang , Xiong Zhengwei
Published: May 2021

Manipulating metal–insulator transitions in strongly correlated materials is of great importance in condensed matter physics, with implications for both fundamental science and technology. Vanadium dioxide (VO2), as an ideal model system, is metallic at high temperatures and shown a typical metal–insulator structural phase transition at341 K from rutile structure to monoclinic structure. This behavior has been absorbed tons of attention for years. However, how to control this phase transition is still challenging and little studied. Here we demonstrated that to control the Ag nanonet arrays (NAs) in monoclinic VO2(M) could be effective to adjust this metal–insulator transition. With the increase of Ag NAs volume fraction by reducing the template spheres size, the transition temperature (T
c) decreased from 68 ° C to 51 °C. The mechanism of T
c decrease was revealed as: the carrier density increases through the increase of Ag NAs volume fraction, and more free electrons injected into the VO2 films induced greater absorption energy at the internal nanometal–semiconductor junction. These results supply a new strategy to control the metal–insulator transitions in VO2, which must be instructive for the other strongly correlated materials and important for applications.
Ultrafast carrier dynamics of Cu2O thin film induced by two-photon excitation*
Authors: Liu Jian , Li Jing , Mu Kai-Jun , Shi Xin-Wei , Wang Jun-Qiao , Mao Miao , Chen Shu , Liang Er-Jun
Published: May 2021

Cuprous oxide (Cu2O) has attracted plenty of attention for potential nonlinear photonic applications due to its superior third-order nonlinear optical property such as two-photon absorption. In this paper, we investigated the two-photon excitation induced carrier dynamics of a Cu2O thin film prepared by radio-frequency magnetron sputtering, using the femtosecond transient absorption experiments. Biexponential dynamics including an ultrafast carrier scattering (< 1 ps) followed by a carrier recombination (> 50 ps) were observed. The time constant of carrier scattering under two-photon excitation is larger than that under one-photon excitation, due to the different transition selection rules and smaller absorption coefficient of the two-photon excitation.
Accurate GW
0 band gaps and their phonon-induced renormalization in solids*
Authors: Shen Tong , Zhang Xiao-Wei , Zhang Min-Ye , Jiang Hong , Li Xin-Zheng
Published: May 2021

Recent years, huge progress of first-principles methods has been witnessed in calculating the quasiparticle band gaps, with many-body perturbation theory in the GW approximation being the standard choice, where G refers to Green’s function and W denotes the dynamically screened Coulomb interaction. Numerically, the completeness of the basis set has been extensively discussed, but in practice far from carefully addressed. Beyond the static description of the nuclei, the electron–phonon interactions (EPIs) are ubiquitous, which cause zero-point renormalization (ZPR) of the band gaps. Therefore, to obtain high quality band gaps, one needs both accurate quasiparticle energies and accurate treatments of EPIs. In this article, we review methods on this. The completeness of the basis set is analyzed in the framework of linearized augmented plane waves, by adding high-energy local orbitals (HLOs). The electron–phonon matrix elements and self-energy are discussed, followed by the temperature dependence of the band gaps in both perturbative and non-perturbative methods. Applications of such an analysis on bulk wurtzite BeO and monolayer honeycomb BeO are given. Adding HLOs widens their GW
0 band gaps by ∼ 0.4 eV while ZPR narrows them by similar amount. These influences cancel each other, which explains the fortuitous agreement between experiment and theory when the basis set is incomplete and the EPIs are absent. The phonon-induced renormalization, a term often neglected in calculations of the band gaps, is also emphasized by its large magnitude.
Carbon dioxide footprint reduction by retrofitting regional heating boilers from gaseous to biogenic fuels
Authors: Antonescu N. , Stanescu D. P.
Published: May 2021

Carbon dioxide footprint reduction can be reached by switching fossile combustible consumers to biogenic fuels. Using biogenic fuels, mainly cellulosic ones, requires burner replacement and most often a complete change of burning process by introducing pre-burning chambers. The boiler response is also to be studied because the changes in flue gases composition, debits and temperatures. The paper analyses the necessary burning installation retrofitting for the case of switching a local boiler from gaseous fuel functioning to cellulosic fuel functioning (sawdust or pellets). It is presented a calculation method for boiler functioning verification (determining the functioning parameters considering an existing boiler used in other than nominal conditions) with the aim of determining the parametrical and performances variations when using other fuels. The nominal functioning regime, for witch there are available experimental data, is used to validate the model and the computational program. Conclusions are drawn regarding the possibility and results for retrofitting regional heating boilers from gaseous to biogenic fuels.
An alternative solution for insulating a burning chamber with high temperature walls
Authors: Tacutu Laurentiu , Antonescu Nicolae
Published: May 2021

Usually, the industrial halls, who are in most cases poorly insulated and have high permeability, are heated with hot air generators or convecto-radiators. Using convecto-radiators is improper and hot air generators, although it is more appropriate, it consumes a very high amount of energy. This paper continues the topic discussed in a previous article [1] in which we presented an alternative heating solution to the existing ones. The heating system mentioned uses an environmentally friendly and cheap fuel (biomass). This paper presents an alternative solution to insulate a burning chamber (BC) with high temperature walls that uses pellets as fuel. This technical solution has the benefit of supplying heating agents to various types of heat consumers and to optimize the construction costs through the materials used. The BC is design with external ribs on here longitudinal direction. For insulating and cooling the BC, a metallic case was design through which atmospheric air is circulated. Three constructive solutions of BCs were analysed. The paper presents the modelling results of the constructive solutions and the calculation method. The calculation was made applying the physical laws that govern this type of heat transfer and was made with discretization segments. Determining the parameters of each segment will allow the user to optimize the equipment design. The main purpose of the study is to conceive an alternative technical solution for insulating the BC, that should be cheaper, easy to implement and able to prepare a second thermal agent for heating.
Thermal energy storage system applicable to vehicles
Authors: Banyai D V , Opruta D , Marcu I L , Merca C G
Published: May 2021

The paper presents the state of the art for thermal energy accumulators using the latent heat phase change usable in cars with either internal combustion engine or electric. The new materials with high storage capacity are presented and the most important achievements in this field of thermal energy storage on vehicles. The case study presented in the paper brings some information necessary for the development of thermal accumulators, with phase change materials, showing the important parameters and characteristics and what values they must have (e.g.: required and accumulated energy; charging and discharging time; latent heat, geometric characteristics). The paper presents a possible classification of these types of batteries, thus facilitating the development of products specific to the applications in which they are included. The work will continue with numerical and experimental studies on models developed based on the case study described here. If at present, in the case of electric cars, a reduction of approx. 20% of electricity was obtained by implementing thermal batteries with phase change material, then studies or research become necessary to accelerate their development on an industrial scale in competitive economic conditions.
Health Assessment and Indoor Environmental Quality in Multiple Romanian Rural Schools
Authors: Ghita S A , Catalina T , Lungu C
Published: May 2021

The current study was realized in three schools located in regional Romania. The results of this article draw upon the diversity of school’s typologies analyzed: new, existing refurbished and old. The analysis was carried using answers given by 138 children to a survey that covered questions related to their learning environment and health problems. Children were asked to rank the perceived quality of several indoor environment parameters (IAQ, outdoor air quality, illumination, noise), the stressful and friendly nature of the schools, and their overall satisfaction. The survey was accompanied by experimental measurements of air temperature, humidity, noise and illuminance levels, CO2 concentration and dust particles. The most prevalent symptoms experienced at school were sneezes (34.1%), fatigue (18.9%), runny nose (14.5%), stuffed/blocked nose (11.6%), and headache (8.7%). Out of the five main health symptoms reported at school, the majority has been recorded in the renovated school.
Mixture Between Fire and Mist Jets Characteristics for Flame Extinguish
Authors: Pavel D , Cozma P , Dimitriu S , Chisacof A , Safta C A
Published: May 2021

The extinguish process using the water mist jet is one of the most efficient system for hydrocarbon flame accidentally developed. The environmentally friendly of the system is an important challenge. Both free jets characteristics are analysed in aim to have a quick suppression of the flame. The paper is focused on the geometrical shape of the cone realised by every jet (flame and water mist). On this basis the relative position of the jets is decisive in aim to obtain the desired effect. Experimental measurements were made, and the results are presented in the paper including the infrared temperature field. The experimental analysis allows to find the adequate angle between jets for the flame extinction. So, the optimum position of the water mist jet applied on the fire was found. A thermal flame extinguish efficiency evaluation is presented, too. The system is non pollutant and the damages are reduced.
Analyses of wall surface condensation risk, based on CFD model with conventional room radiator
Authors: Ivanov M P , Mijorski S G
Published: May 2021

The presented paper reveals a numerical study of the risk of condensation over exterior wall of a typical residential room. The study is based on CFD methods with implemented conjugate heat transfer. The analysis is contributed by a study of the impact of the heat released from conventional room radiator with various heat loads. This way, the resulting surface and dew point temperature distributions are derived over the simulated exterior wall. The results demonstrate that with the increase of the room relative humidity, the percentage of the external wall area, which might be affected by condensation increases significantly. This effect is observed regardless of the selected increase of the radiator heat load (in this particular study, the range is between 1000 W and 1500 W). For the range of relative humidity values from 40% to 60%, the area with increased risk of condensation increases to above 80%. This result demonstrates the crucial importance of the control of the room relative humidity within occupied premises, especially if condensation mitigation measures must be applied. The presented analyses and assessment method are rather innovative for the presented engineering area and would be in help in the buildings and indoor environment design process.
Study on the behavior of a high reinforced concrete building with different kinds of partitioning masonry walls
Authors: Constantinescu S
Published: May 2021

The paper is a study on different types of masonry partitioning walls in a high rise reinforced concrete walls building. It will be built in Bucharest, Romania. The masonry walls are made of clay bricks for the first 4 cases studied and aerated concrete blocks for the last 2 cases. They are designed to bare the in plane and perpendicular efforts they are subjected to in the elastic stage. The effect these masonry walls have on the structures is shown. They have an important influence over the buildings natural vibration periods and the slabs reinforcement design and shear stresses. The plastic hinges development is shown for all 6 cases. The pushover diagrams are compared separately for directions X and Y.
Experimental study of water losses through a circular leakage hole in PVC pipes
Authors: Hotupan A , Hădărean A
Published: May 2021

The water loss is a phenomenon which attends the water supply system on its operating lifetime and it represents the difference between the water volume measured at the input of a water distribution network and the water volume billed to the end-users. The water loss reduction is an important topic for the water supplying companies and the knowledge of the real water volumes lost from a supply system is an essential element in water balance. The water losses may be classified in “real losses” and “apparent losses”: the apparent losses cannot be quantified, but the real losses can be estimated by calculus. The complexity of this phenomenon lies in the fact that this water losses can’t be calculated with a single equation, generally valid for each real situation. The equations mentioned in the technical literature can be applied to a specific situation. This paper presents an experimental study of the variation of the hydraulic parameters in a PVC water flow pipe in two cases: 1. normal operation and 2. leak simulation, when a circular hole is drilled into a PVC pipe. Furthermore, the results of this study are discussed and analysed in order to calculate the value of the leakage exponent N
1.
Overview of resilience: a concept to assess healthcare infrastructure preparedness against disasters. Evaluation of existing models and applicability to HVAC systems
Authors: Garrido-Píriz P , Botejara-Antúnez M , Sánchez-Barroso G , González-Domínguez J , García-Sanz-Calcedo J
Published: May 2021

Healthcare infrastructures are critical and have elements which are likely to fail or to get collapsed in disaster scenarios (earthquakes, pandemics, etc.). There are many parameters and factors to evaluate their preparedness, but resilience has outstood in recent investigations. Hospitals must not only be prepared for disasters to come, but also to reach the nominal operation in the aftermath as soon as possible, as these infrastructures play a critical role in modern societies. The aim of the study is to evaluate and assess different insights into resilience, as well as marking possible improvements, providing a deeper understanding about the topic and concepts that surround the definition of resilience. The result is the constitution of a new assessment tool based on semi-quantitative and quantitative models. The model can be scaled and applied to internal systems in healthcare infrastructure such as HVAC facilities.
Study of energy consumption in a wastewater treatment plant using logistic regression
Authors: Boncescu C , Robescu L D , Bondrea D A , Măcinic M E
Published: May 2021

The aim of this paper is to predict the energy consumption of a wastewater treatment plant from Romania, taking into account the flowrate, concentration of BOD, TSS, COD and the energy consumption. For the mathematical model the logistic regression was applied. The input data used were from a waste treatment plant in Romania, for a period of 2 years 2015 and 2017, a total of random 403 dataset. The treatment technologies of WWTP consist of advanced biological treatment SBR (nitrification, denitrification, and phosphorus removal), aerobic sludge stabilization, dewatering, storage and chemical disinfection. Octave software was used to build the model. The answer of the model refers to the fact that for a given situation there will be high energy consumption or low energy consumption in the wastewater treatment plant (WWTP). Performance of the model was compared with real value.
Experimental research on a hydrokinetic turbine model
Authors: Nedelcu A , Bunea F , Danca P A , Chihaia R A , Babutanu C A , Marin D , Ciocan G D
Published: May 2021

The renewable energy policy strongly encourages the use of all renewable sources of energy. ICPE-CA starts to develop a new hydrokinetic turbine to be implemented in small rivers or water channels with a low investment cost. In a first step, the characterization of a laboratory reduced scale turbine model is performed. The hydrokinetic turbine model is implemented in a free surface water channel. The produced power for many flow rates and rotation speed of the turbine, as well as the detailed flow characterization (PIV measurements) are presented.
Experimental and numerical investigation of plain concrete columns strengthening by FRCM composite material
Authors: Hasan H , Pascu R , Georgescu D P
Published: May 2021

The Fibre Reinforced Cementitious Matrix (FRCM) composite material is a relatively new retrofitting system which overcomes the limitations related with the use of organic adhesives. FRCM system is used to increase the strength and overall ductility of masonry and concrete structures. This paper presents the results of an experimental program on plain concrete columns strengthened by FRCM under uniaxial compression loading. Six columns of square 30x30 cm cross-section and 100 cm height made of low-strength concrete were cast in place. Two columns without confinement are used as reference, while two columns with one layer of FRCM and two columns with two layers of FRCM are used to investigate the influence of FRCM confinement level. The FRCM system consists of high-strength carbon fibre mesh and cementitious mortar. The performance of FRCM strengthened columns is evaluated in terms of ultimate axial load carrying capacity, ultimate axial deformation, ultimate stress and ultimate strain. The experimental results are also compared with the numerical results obtained according to ACI 549.4R-13 code.
The Reduced Stress Method (EN-1993-1-5) In Designing of The Plated Structural Elements
Authors: Tawfeeq Al-Aqbi Ameer , Popa Nicolae
Published: May 2021

The paper describes the main features and advantages of European standard EN 1993-1-5 in the design of plated structures. Compared to other types of steel structures, plated structures are more prone to local buckling and therefore required design rules to cover such a phenomenon. The concept of the article focuses on The Reduced Stress Method. A steel box girder chooses for numerical example was fabricated of S235 steel, has 7 panels with transverse and longitudinal stiffeners and was tested in 1985 at the Testing Laboratory of the Research Institute for Transportation Engineering, in Bucharest.
Analysis of the pollution degree of the geological environment on a petroleum product storage & distribution site
Authors: Petruta A M , Bica I
Published: May 2021

The study presented in this paper was conducted on a site pertaining to the distribution & storage component of the oil industry, the business of which was mainly the supply, using railroad and road transportation means, followed by storage in tanks and trading of petroleum products (e.g. gasoline, diesel oil, various oils). To carry out its activity, the site had the following technological equipment: vehicle loading platform/railway unloading platform, storage tanks, pumping station, hydrocarbon separator, technological transport pipes, storage areas, administrative buildings, etc. Based on the characteristics of industrial sites, a synthesis of the particularities of these site types was made. To that effect, the direct connections in terms of the specificity of the main and auxiliary activity were taken into account, as well as the handled chemicals and raw materials, but also how the waste was managed during the operational processes.
Studies on geothermal energy utilization: a review
Authors: Andronache M M , Teodosiu C
Published: May 2021

Sustainable development requires the use of sustainable energy systems. Energy use will increase worldwide, and geothermal energy consumption for both electricity generation and heating will also increase significantly. Sustainable use of geothermal energy means that it is produced and used outdoors, which is compatible with the well-being of future generations and the environment. This paper provides a review of the links between the development of geothermal energy used in HVAC systems and sustainable development, as well as a review of the sustainability assessment frameworks currently available.
Innovative technologies in constructions. Self-repairing concrete used in road infrastructure
Authors: Barbu A M , Stoian M M
Published: May 2021

Currently, concrete is the most widely used structural material in road infrastructure. Concrete is a sensitive material, cracks and micro-cracks may occur during operation. Although the cracking/micro-cracking of concrete does not implicitly cause structural damage, it creates a path for corrosive factors, which leads to decreased structural durability caused by material changes and reinforcement corrosion. The self-repairing ability of concrete refers to the process of closing cracks to prevent the entry of potentially aggressive agents. Concrete used in bridge construction is usually covered with a waterproof layer and a layer of asphalt mixture, which also acts as a wear layer, but which can prevent the entry of water containing corrosive ions, the natural aggressiveness of the environment or accelerated corrosion by the penetration of thawing substances etc. Road infrastructure repair works affected by degradation processes are costly, time consuming and lead to a reduction in traffic flow, by partially closing it during interventions. To overcome these shortcomings, over time, several types of concrete with self-repairing properties have been developed, based on several methods such as: pipe networks, superabsorbent polymer capsules and textile fibers, bacteria etc.
Study of soil characteristics after treatment with lime-based hydraulic binder using the in situ “layer by layer” stabilization method
Authors: Andries G , Carasca O , Batali L
Published: May 2021

Paper presents the results obtained in situ and in laboratory for a test section where the soil has been improved by mixing with a lime-based hydraulic binder. The treatment has been applied in order to obtain a more uniform soil bearing capacity, thus reducing the differential settlement that could appear between adjacent foundations or under the same foundation. The test section has been performed by mixing the local cohesive soil (silty clay) with 4% special lime-based hydraulic binder, then compacted in 3 layers, 20 cm thick each after compaction, resulting a final compacted layer of 60 cm. For this treatment a laboratory study has been conducted in order to determine the optimum binder admixture. The physical and mechanical characteristics of the improved soil have been studied in laboratory and in situ for 3 curing times: 3, 7 and 28 days. In laboratory have been carried out tests for identification and classification, for determining the density and water content, followed by mechanical tests as oedometers and shear box tests, while in situ Lukas plate tests have been performed. Paper presents results of all tests, including analyses and interpretation.
EFdeN Signature - a case study of a zero-energy house prototype optimized for Middle East climate
Authors: Baiceanu M. , Catalina T. , Ilisei G. , Chelariu A.
Published: May 2021

When talking about the urban challenges we face today at a global level, population growth and urbanization ranks high in the charts. Both challenges can be found in the Middle East and especially in Dubai, one of the fastest growing cities in the world - a rapidly developing urban settlement supporting an ever-increasing human population. With a very warm climate, the United Arab Emirates are struggling to develop strategies and solutions to decrease energy consumption. Among the major consumers in Middle East are the building therefore an integrated approach using renewable sources is mandatory. Within the Solar Decathlon competition the Romanian team of students proposed a house prototype to answer Middle East challenges. In this paper we present the developed model, its structure, systems and we demonstrate its potential as a positive energy balance building using numerical simulations.
A review of the usage of highly viscous fluids in industrial applications
Authors: Niculuta M C , Ghiaus A-G
Published: May 2021

Highly viscous fluids (HVF) are used in food sector as raw materials (melted vegetable, animal fats) or finished products (chocolate, sorbets), in construction sector as liquid state of Phase Change Materials (PCM) used to store thermal energy inside building structure or building materials such as liquid concrete, bitumen and tar, in automotive industry as PCMs used to passively cool batteries, and many others. Some applications are rather new and lot of research has been done, in the last decade, to find mathematical models for predicting HVF behaviour, in heat and mass transfer processes in scraped surface heat exchangers, in vegetable fat melters and in waxy crude oil transport pipelines. Better results could be obtained by enhancing HVF thermal properties such as increasing the thermal conductivity of PCMs by adding metallic powders, or by finding new natural materials (vegetable fats) which can replace more expensive and harmful ones (waxes) for PCMs. This study was performed to shortly present the main applications in which HFVs are being used, the main advances and findings made in the last years and the current challenges and research possibilities which are likely to be explored in the future.
Forming spatial thinking skills of social studies students in phenomenon analysis geosphere through the Geographic Information System (GIS)
Authors: Wahyuningtyas N , Laila N , Andini F
Published: May 2021

Spatial thinking skills are characteristic and an important part of learning geography. Geography studies in which various analyzes geosphere is phenomena can be solved by spatial thinking. Resolve geosphere phenomena, for example, disaster vulnerability can be assessed using assistance from Geographic Information Systems (GIS). Article writing procedure was carried out by examining, comparing, and interpreting the results of similar studies that have been explained in the form of journals and articles. Data analysis was performed using qualitative descriptive analysis techniques. Based on the analysis results it is described that the Geographic Information System (GIS) provided an important role in creating and improve skills students’ spatial thinking. GIS provides opportunities for social studies students to explore the geosphere phenomenon in the surrounding environment uses technology. Increased spatial thinking skills make students better recognize the condition of the surrounding environment from various aspects of both threats, vulnerability, and risk of disaster.
Local history online learning strategies: teacher’s perception
Authors: Gunawan R , Rachmah H
Published: May 2021

The purpose of this research is to determine the appropriate strategy in teaching local history according to the teacher’s perception. Usually, local history learning is done directly by making visits to historical places so that it can build a complete picture of an event. However, when learning is being carried out at home, the teacher must be able to determine how to properly teach local history online. This study used a case study research design by taking cases that occurred in the province of DKI Jakarta. Data were collected from history teachers who were involved in history teacher forums and conducted online through interviews and observations via online videos. The results of this study indicate that local history learning can be done online by providing information to students on online site addresses related to local history in DKI Jakarta cultural heritage sites. Hands-on practice carried out by students can help students think critically and give them awareness about the importance of knowing the local history around them to see the world comprehensively.