bluuebunny/crossref_metadata_2025 huggingface dataset:
Pursuing the excision of carbon-centred hexanuclear scandium clusters {CSc
Authors: Demir Selvan , Tyrra Wieland , Schmitz Simon , Klein Axel , Meyer Gerd H.
Published: February 2022

A multi-gram synthetic route to black solid {CSc6}I12Sc (1) was developed which comprises the reaction of scandium triiodide, ScI3, with graphite and scandium metal at 850°C. Compound 1 dissolved in N,N-dimethylacetamide (DMA) to form a red solution. Results derived from 45Sc NMR and EPR spectroscopy indicated that a scandium cluster species exists in this solution along with a complex cation [Sc(DMA)6]3+. From these solutions crystals of [Sc(DMA)6]I3 (2) and a red oily product was isolated. Compound 2 was also prepared independently by dissolving ScI3 in DMA and two polymorphs, orthorhombic 2O and monoclinic 2M were crystallised. {CSc6}I12Sc (1) also dissolved in THF yielding a red solution which contains [ScI6]3− and a scandium cluster species, as analysed by 45Sc NMR and EPR spectroscopy.
Theory-driven approaches and empirical advances
Authors: Giusti Giuliana , Cardinaletti Anna
Published: February 2022

Italo-Romance varieties present at least three types of constructions that cluster together two verbs displaying double tense and double subject agreement and are taken as Pseudo-Coordinations (PseCos) or Multiple Agreement Constructions (MACs). In this paper, we follow Cardinaletti and Giusti’s (1998, 2001, 2003, 2020) hypotheses and claim that unification between the PseCos with a and the MACs with mu/mi/ma or ku in Southern Italian dialects is not viable. We adopt a diagnostic tool, which we call a protocol, that clusters the predictions of theory-driven analyses and apply it to the ‘take and’ construction, which is widespread across dialects and productive in Italian. In doing so, we discuss unobserved facts arising in the well-studied dialectal structures and make fine-grained observations about the less studied ‘take and’ PseCo in Italian.
A particle-like use of hwæþer Wisdom’s questions in Boethius
Authors: Eckardt Regine , Walkden George
Published: February 2022

The paper investigates unembedded hwæþer questions in Old English (OE). We argue that they
represent an intermediate stage in the development of hwæþer ‘which of the two’ to modern English
whether. Syntactically, we find a range of quasi-subordinating uses of hwæþer in
questions that all have in common that the speaker expresses a pedagogical question. Pedagogical questions are
questions the speaker knows the answer to, but is urging the addressee to consider while drawing their own
conclusions. In the OE Boethius, hwæþer can convey this use-conditional pragmatic flavour for polar
questions. It thus comes close in function to other use-conditional particles.
Extravagance, productivity and the development of -ingly adverbs
Authors: Killie Kristin
Published: February 2022

The paper claims that the process of deriving -ly adverbs from present participles has become increasingly productive over the last 500 years. It is argued that many ‘-ingly adverbs’ are extravagant, in the sense of Haspelmath (1999). This claim is supported by the fact that such adverbs are very common in prose fiction, which is a genre that admits of extravagant language. It is hypothesised that the category of -ingly adverbs has evolved around a few frequent types but that extravagant -ingly uses have caused the category to expand by pushing at the boundaries of what is considered acceptable. The change is explained within an exemplar-based model of morphological change and against the backdrop of ‘adverbialisation’.
A new model of performance classification to standardize the research results in swimming
Authors: Ruiz‐Navarro Jesús J. , López‐Belmonte Óscar , Gay Ana , Cuenca‐Fernández Francisco , Arellano Raúl
Published: February 2022

The level of expertise must be defined for the sample studied when reporting research in sport. Concretely in swimming, apart from the participants’ background, the competitive status is based on the level that swimmers participate. Thus, the International Swimming Federation (FINA) points are added to improve the sample level characterization. The aim of this study was two‐fold: (1) to assess whether national and regional swimmers from different countries differ in their performance level (based on FINA points), and (2) to propose a model that allows standardizing the research results in swimming. The FINA points of 5876 participants (males = 2962 and females = 2914) in 100 m butterfly, backstroke, breaststroke and freestyle were retrieved from nationals (n = 21) and regionals (n = 44) swimming competitions. One‐way analysis of variance was conducted to test the difference in FINA points between swimmers of different countries. Significant disparities (100–350 FINA points; p < 0.001) were observed in national and regional competitions for male and female swimmers among the different countries analyzed. This could lead to misleading conclusions when comparing studies with national or regional swimmers from different countries. In this regard, a new model of performance classification based on national and regional worldwide competition is proposed. This might be used to standardized the swimming research results.

Highlights

‐ The current classification of swimmers’ status could lead to misleading conclusion when comparing studies from different countries using national or regional swimmers.

‐ The proposed model will allow to better standardize the research results in swimming, aiding to draw more accurate conclusion when comparing results from different studies.
Five-dimensional electrostatic black holes in a background field
Authors: Tomlinson Fred
Published: February 2022

We consider five-dimensional electrostatic solutions to Einstein–Maxwell gravity with two commuting spacelike Killing fields. Taking two distinct reductions from five dimensions to a three-dimensional base space, we write the Einstein–Maxwell equations using some axially symmetric functions on

R

3

. These equations can be viewed as arising from a harmonic map coupled to three-dimensional gravity with the isometries of the target space of this map revealing a hidden

S
L

(

2
,
R

)

symmetry of this sector of the theory. Depending on the choice of reduction this symmetry then gives rise to two different one-parameter families of transformations corresponding to either charging a black hole or immersing it in a background electric field. We use these transformations to charge a static black Saturn and a static L(n, 1) black lens spacetime and by tuning the strength of the external field, we cure the conical singularities to give new regular solutions. Notably the electrified black lens generated is the first example of a regular black lens in Einstein–Maxwell gravity with topologically trivial asymptotics.
Nonlinear harmonics coupled by parallel wave propagations in a time-dependent plasma flow
Authors: Uk Lee Min , Yun Gunsu S , Ji Jeong-Young
Published: February 2022

In a time-dependent flow, nonlinear harmonics can be excited by coupling between linear waves and flow-induced harmonic waves. Examining the dispersion relations and selection rules for the coupling, we investigate nonlinearly coupled harmonics for waves propagating along the magnetic field line in a magnetized plasma, as well as waves in an unmagnetized plasma. The coupled harmonics in a plasma flow are described by analytic dispersion relations and selection rules. This nonlinear coupling is corroborated by the particle-in-cell simulation. The coupled-harmonics model describes a mechanism for the excitation of nonlinear harmonics from linear waves in a time-dependent flow. The spectral analysis of the dispersion relation provides a useful way to evaluate the spatiotemporal behavior of a plasma flow.
Regularization dependence of pion generalized parton distributions *
Authors: Zhang Jin-Li , Kang Guang-Zhen , Ping Jia-Lun
Published: February 2022

Pion generalized parton distributions are calculated within the framework of the Nambu–Jona-Lasinio model using different regularization schemes, including the proper time regularization scheme, the three-dimensional (3D) momentum cutoff scheme, the four-dimensional momentum cutoff scheme, and the Pauli-Villars regularization scheme. Furthermore, we check the theoretical constraints of pion generalized parton distributions required by the symmetries of quantum chromodynamics in different regularization schemes. The diagrams of pion parton distribution functions are plotted, in addition, we evaluate the Mellin moments of generalized parton distributions, which are related to the electromagnetic and gravitational form factors of pion. Pion generalized parton distributions are continuous but not differential at

, when considering the effect of the contact contribution term, generalized parton distributions become not continuous at

in all the four regularization schemes. Generalized parton distributions in impact parameter space are considered, the width distribution of u quark in the pion and the mean-squared

are calculated. The light-front transverse-spin distributions are studied when quark polarized in the light-front-transverse

direction, the transverse-spin density is no longer symmetric around

, the peaks shift to

, we compare the average transverse shift

and

in different regularization schemes. The light-cone energy radius

and the light-cone charge radius

are also evaluated, we found that in the proper time regularization scheme the values of these quantities were the largest, in the 3D momentum cutoff scheme they were the smallest.
A New X-Ray Tidal Disruption Event Candidate with Fast Variability
Authors: Hampel J. , Komossa S. , Greiner J. , Reiprich T. H. , Freyberg M. , Erben T.
Published: February 2022

During a close encounter between a star and a supermassive black hole, the star can get disrupted by the black hole’s tidal forces, resulting in a tidal disruption event (TDE). The accretion of the star’s material onto the black hole produces strong emission in different wavelength regimes. Here we report the discovery with the Roentgen Satellite (ROSAT) of an X-ray-selected transient source in an optically non-active galaxy. At the location R.A.: 13h 31m57.ˢ66 and decl.: −32°43′19.″7 a sudden rise in X-ray luminosity by a factor of 8 within 8 days has been observed. Additionally, a very soft X-ray spectrum with a blackbody temperature kT = 0.1 keV and a peak luminosity of at least 1 × 1043 erg s−1 suggests a TDE interpretation, and the observed properties are very similar to previously identified soft X-ray (ROSAT) TDEs. An optical spectrum taken of the galaxy at the position of RXJ133157.6324319.7 six years after the X-ray outburst does not show any emission lines as would be expected from a persistent active galactic nucleus. The redshift of the galaxy is determined to be 0.051 based on absorption lines. It is therefore likely a member of the galaxy cluster A3560. The rise in X-ray luminosity happens within 8 days and thus appears to be fast for such an event. No X-ray emission was detected 170 days before and 165 days after the event, and none was detected 25 yr later with the Neil Gehrels Swift Observatory. The change in X-ray luminosity is at least a factor of 40.
Efficient quantitative assessment of robot swarms: coverage and targeting Lévy strategies
Authors: Duncan S , Estrada-Rodriguez G , Stocek J , Dragone M , Vargas P A , Gimperlein H
Published: February 2022

Biologically inspired strategies have long been adapted to swarm robotic systems, including biased random walks, reaction to chemotactic cues and long-range coordination. In this paper we apply analysis tools developed for modeling biological systems, such as continuum descriptions, to the efficient quantitative characterization of robot swarms. As an illustration, both Brownian and Lévy strategies with a characteristic long-range movement are discussed. As a result we obtain computationally fast methods for the optimization of robot movement laws to achieve a prescribed collective behavior. We show how to compute performance metrics like coverage and hitting times, and illustrate the accuracy and efficiency of our approach for area coverage and search problems. Comparisons between the continuum model and robotic simulations confirm the quantitative agreement and speed up by a factor of over 100 of our approach. Results confirm and quantify the advantage of Lévy strategies over Brownian motion for search and area coverage problems in swarm robotics.
Effect of Inorganic Fertilizer on Morphological and Physiological Responses In ‘Siam’ (Tangerine) and ‘Keprok’ (Mandarin) Seedlings Under Nursery House
Authors: Hardiyanto  , Devy N F
Published: February 2022

The growth of citrus seedlings has not only been influenced by fertilizer management but also species and cultivar as well. The purpose of this study was to evaluate the growth performance of Siam and Keprok seedling to inorganic fertilizer treatment under nursery house. Research was conducted in Nursery House, ICISFRI, Batu, East Java, Indonesia from February to November 2020. Factorial Randomized Block Design was used in this research consisted of two factors, I: Doses (0 %; 50 %: 2.5 g NPK + 2.5 g ZA/plant), and II: Cultivars (Tangerine/Siam cv. Banjar, Madu, and Pontianak; Mandarin/Keprok cv. Gayo, Kacang, and Madura) with three replications. An orthogonal contrast analysis was also used to identify the response of Tangerine and Mandarin group. Among 16 variables, only plant height, leaf thickness, and shoot dry weight were significantly influenced by the interaction between doses and cultivars with value of p<0.01; R2= 98.08 %; p<0.05; R2= 85.77 %; and p<0.01; R2= 99.14 %, respectively. Eight of 16 morphological and physiological traits (50 %) applied with either 0 % or 50 % gave similar responses between Mandarin and Tangerine group. Application of 50 % and 0 % produced 68.80 % and 81.30 % of similarities between Tangerine cv. Pontianak and Banjar, respectively. Meanwhile, similarities of Tangerine (Pontianak and Banjar) versus Tangerine cv. Madu that was applied with 0 % and 50 % of fertilizer application were 68.75 and 93.75 %, respectively.
Root Growth and Yield of Rice Plant Associated with Arbuscular Mycorrhizal Symbiosis Under Salt Stress
Authors: Adillah A , Widada J , Kurniasih B
Published: February 2022

The presence of excessive salt around root system disrupts water and nutrient uptake by root, causes inhibition of plant growth resulting in low plant yield. Arbuscular mycorrhizal (AM) symbiosis known for its mutualism towards plant by enhancing plant root growth. This study examined how AM symbiosis improved root growth and yield of rice plant under different salinity levels. The experiment was conducted in the screenhouse of Faculty of Agriculture, Universitas Gadjah Mada which arranged in a Randomized Complete Block Design (RCBD) with two factors. The first factor was rice plant that applied with and without arbuscular mycorrhizal inoculum. The second factor was four salinity levels at 0 dS m-1 (non-saline), 2.5 dS m-1, 5 dS m-1, 7.5 dS m-1. The results showed that the increase of salinity level treatment was followed by increasing of root Na content, resulting in decreasing of root growth as well as plant yield. Higher colonization rate in mycorrhizal plant than non-mycorrhizal plant caused two-fold increase in root cation exchange capacity (CEC). Under salinity, roots of mycorrhizal plant became longer and thicker, also root fresh weight did not decrease compared to non-mycorrhizal plant. By having higher root CEC and more extensive root, mycorrhizal plant was able to alleviate yield loss under 7.5 dS m-1 salinity stress.
Adaptation of Three Local Garlics (Allium sativum L.) in Napu Plateau Central Sulawesi
Authors: Saidah  , Muchtar  , Wahyuni A N , Irmadamayanti A , Risna  , Syafruddin  , Rahayu Heni S P , Sugito
Published: February 2022

One of the challenges in developing garlic in Indonesia is increasing its competitiveness. It means that the price and quality must be able to compete with imported garlic. Apart from that, productivity also needs to be increased. Currently, the national demand for garlic is estimated at 539.3 thousand tons per year (2016-2019), where domestic production only reaches 134.7 tons. Therefore, the rest number is fulfilled by importing. This condition has spurred many parties to take part in supporting the garlic development program, including the Central Sulawesi provincial government. Napu Plateau in Poso District Central Sulawesi Province is an area above 1000 meter of sea level and has A rain type with agro-climatic zone A1. This condition is very suitable for the development of vegetable crops, including garlic. The research objective was to determine the adaptability of three local varieties of garlic. The activity was carried out in Watumaeta Village, North Lore Subdistrict, Poso District, Central Sulawesi in April-July 2020. The study used a Randomized Block Design with treatments of three local varieties of garlic, namely Lumbu Hijau, Sembalun and Tinombo. Number of repetitions were five units. Observed parameters included plant height, number of leaves and stem diameter, bulb diameter, bulb weight, and number of cloves. The results showed that the garlic varieties have no significant effect on all observed parameters, except stem diameter, bulb dry weight and number of cloves. Those three local varieties have average number 54,70-58,18 cm of plant height; 7,70-8,08 of leaves; 0,35-0,42 cm of stem diameter; 2,41-2,78 cm of cloves diameter; bulb dry weight 11,92-17,09 gram; 4,10-4,90 of number of cloves. Among the three local varieties, Tinombo from Parigi Moutong District was superior compare to the other two varieties.
Regulatory and Policy Responses toward SDGs in Achieving Sustainable Agriculture Productivity in Indonesia
Authors: Nasrullah  , Ovitasari M
Published: February 2022

As one of the countries adopted the United Nations Resolution 70/1 on the agenda entitled “Transforming Our World: 2030 for sustainable development to end hunger, achiever food security and improved nutrition and promote sustainable agriculture, Indonesia is duty bound to realize these Sustainable Development Goals (SDGs) by 2030. The purpose of this study is to identify and analyze the regulatory framework and government policy towards SDGs in achieving sustainable agricultural productivity in Indonesia. This research is normative legal research with a statutory approach and an analytical approach to the problem of agricultural development in Indonesia. By using a qualitative descriptive method, this study would describe government regulations and policies related to SDGs in achieving sustainable agricultural development. The result of this study shows that the regulations and policies set by the Government of Indonesia are in line with the Sustainable Development Goals in particular the second goal of increasing agricultural productivity in a sustainable manner especially the second SDGs goals, namely ending hunger by revitalizing agriculture and increasing the competitiveness and value added of agricultural commodities. However, this regulatory framework cannot be said to be effective in realizing sustainable agriculture productivity in Indonesia because the related regulations are not optimal and comprehensive.
Groundwater in Bener area, its quality and contribution for agriculture
Authors: Listyani T , Prabowo I A
Published: February 2022

The existence of surface water is not always sufficient for the needs of the community, also for agricultural needs. Therefore, groundwater can be an alternative water supply in the irrigation system, so it is necessary to assess its quality. Groundwater quality is the result of the interaction of material (soil/rock), the type of flow/transport and the change processes. The results of these components produce different groundwater quality in each region. To assess the groundwater quality in Bener and its surrounding areas, this research was carried out by direct survey in the field and testing the physical/chemical properties of groundwater in the laboratory. Groundwater sampling was carried out at 6 dug wells and 2 springs. The analysis shows that all samples are bicarbonate groundwater types, with variations of Na+, Ca2+ and Mg2+ dominant cations. Groundwater quality shows a pH value of 6.2 - 6.7, TDS of 45 - 306 ppm, hardness of 39.73 - 200.43 ppm, SAR (Sodium Adsorption Ratio) of 12.12 - 76.64, Na% of 19.81 - 62.11, and RSC (Residual Sodium Carbonate) of 0.04 - 1.35. According to its quality, groundwater can be used to support irrigation for agriculture in the area.
Soil Chemical Properties and Microbial Biomass Respond during Land Use Change
Authors: Parwi  , Muhammad  , Dewanti F D , Priyadashini R
Published: February 2022

In Ponorogo, East Java, Indonesia, pine-based agroforestry was mostly converted to sengon-based agroforestry before partly converted to monoculture. Land-use changes during the process affect soil properties. There is few information about the effects of land-use changes from pine-based agroforestry systems to sengon-based agroforestry systems and monocultures on soil chemical properties and microbial biomass. The aims of this study were to analyze the response of soil chemical properties and microbial biomass to land use changes in latosol Indonesian. Samples from three land-use changes, i.e. pine-based agroforestry, sengon-based agroforestry and monoculture were analyzed. Soil samples were taken at 2 depths, i. e. 0-30 cm and 30-60 cm. As the results, it was found that the land-use change affected the chemical properties and microbial biomass of the soil. Land-used change from pine-based agroforestry to sengon-based agroforestry have no significant effect on pH, organic carbon, available P, and microbial biomass in 0-30 cm depth. Meanwhile, in 30-60 cmdepth, microbial biomass in sengon-based agroforetry was higher than that in pine-based agroforestry. The pine-based agroforestry which was converted into monoculture, reduced the soil organic carbon and available P concentration, contrast with the soil microbial biomass which was increased in 0-30 cm depth. The highest soil microbial biomass was found in sengon-based agroforestry in 30-60 cm depth. The conclusion of this study implicated that land use in monoculture decreased soil fertility. Therefore, conversion of pine-based agroforestry to monoculture is full of risks.
Identification of Land Cover Types and Their Changes in Kutalimbaru Sub-district, Deli Serdang District, North Sumatra, Indonesia
Authors: Rahmawaty  , Kurniawan H , Harahap M M , Rauf A
Published: February 2022

In recent years, land cover changes in Deli Serdang District, North Sumatra Province, have become a problem that needs to be addressed immediately. This study aims to determine the type of land cover that has changed over a ten-year period that occurred in the Kutalimbaru Sub-district. Kutalimbaru Sub-district is upstream of the Belawan Watershed. The method used in this study is a change detection method using a geographic information system (GIS). The results showed ten types of land cover in the Kutalimbaru District: dryland forest, paddy field, mixed garden, open land, oil palm plantation, rubber plantation, settlement, shrubs, water body, and industry. Land cover in Kutalimbaru Sub-district in 2019 was dominated by mixed gardens (39.51), followed by oil palm plantations 23.13% and dryland forests 12.58%. Over ten years, there was a change in land cover from dry land forest to the mixed garden (14.42 ha) and open land (9.22 ha). A significant change occurred in land cover from mixed garden to oil palm plantation (1,783.41%) and to open land (1,178.37 ha). In addition, a change in land cover from mixed garden to settlement (154.99 ha) also occurred in this area.
Biosilica Fertilizer Reduces Fall Armyworm Damage
Authors: Ulina E S , Manurung E D , Hasibuan M , Nasution L Z
Published: February 2022

The presence of fall armyworm (FAW), Spodoptera frugiperda J.E. Smith, in Indonesian corn plantations caused the farmers' dependence on chemical insecticides increased. Since chemical pesticides have several side effects, it is necessary to develop another alternative to FAW management. This study aimed to investigate the efficacy of biosilica fertilizer against FAW incidence and its effect on maize production. A factorial experiment was arranged in two factors, the first factor was biosilica doses with varied doses of 1, 2, and 3 l/ha; the second factor was the number of applications at 1, 2, and 3 times. The results demonstrated that the application of biosilica fertilizer 2 - 3 l/ha as foliar spray three times starting from 10 days after growing reduced the fall armyworm infestation significantly as compared to control treatment. No significant differences were observed in the vegetative characteristics of corn plants, i.e height and the number of leaves, in response to doses and application number of biosilica. Application of biosilica 2 - 3 l/ha improved the yield attributing characters of the corn plant and increased the production as compared to other treatments including control treatment. We conclude that biosilica fertilizer can be used as an alternative for FAW management.
Insecticidal Activity of Bitter Melon (Momordica charantia L.) Leaf Extract on Mung Bean Weevil (Callosobruchus chinensis L.)
Authors: Wahyutami C T , Sarjiyah  , Aisyah S N
Published: February 2022

Infection of mung bean weevil (Callosobruchus chinensis) might cause weight loss of mung bean seeds up to 55-69% and loss of protein content up to 45.6-66.3%. An eco-friendly strategy to manage this storage pest could be performed through the utilization of botanical pesticide, such as the leaf extract bitter melon (Momordica charantiaL.). This study was aimed to investigate the insecticidal activity of bitter melon leaf extract (BMLE) against mung bean weevil. This study was conducted using Completely Randomized Design consisting of 5 dosages of BMLE application (0, 1.4, 2.7, 5.3, and 9.6%) with 5 repetitions. BMLE was applied to 100 g of mung bean seeds, then 10 mung bean weevils were infested into the treated seeds and stored for 38 days in room temperature. Both insecticidal activity and seed quality were carefully observed during the storage period. Results showed that application of 5.3 and 9.6% BMLE exhibited similar mortality of mung bean weevil. Both dosages also showed no negative effect on the seed quality indicating that BMLE might also contribute in maintaining the seed during the storage. Therefore, these results emphasized the promising potential of BMLE to be developed as the botanical insecticide for storage pest.
Potential Use of Coconut Shell Liquid Smoke as an Insecticide on Soybean and the Impact on Agronomic Performance
Authors: Diptaningsari D , Meithasari D , Karyati H , Wardani N
Published: February 2022

One of the limiting factors in increasing soybean production is the high infestation of pests and diseases. Coconut shell liquid smoke has potential as a botanical insecticide on soybeans. This study was conducted to determine potential use of coconut shell liquid smoke on growth and yield of soybean compared to biological insecticide (entomopathogenic fungi) and chemical insecticide on acidic dry land in South Lampung, Lampung Province, Indonesia. The treatments were arranged with three insecticide treatments and two fertilization method (organic and inorganic fertilization), and control without insecticides and fertilizers. The intensity of pest attacks (I) was calculated using Townsend–Heuberger formula. The results showed that there was no significant difference between the treatment of three insecticide applications and two fertilization methods on the agronomic performance and yield of soybeans. Different results were shown in the control without fertilization with lower yield. Pest infestation in coconut shell liquid smoke treatment was smaller than other treatments. Coconut shell liquid smoke has the potential to be developed as a botanical insecticide, with the same results compared to chemical insecticide treatments.
Essentiality of integrated supervision of efficient mineral mining in Northern and Northeastern Russia
Authors: Yakovlev VL
Published: February 2022

The development strategy for deep structurally complex mineral mining and transition processes—a set of technical, technological and organizational measures to adapt geotechnical systems variable conditions of their functioning is defined. As mining is advanced and expands with the associate gain in information on geology and cost/performance, it critical to repeatedly estimate cut-off grades with regard to value of by-minerals and considering parameters of the main process flows involved in mineral extraction, pretreatment and processing. Features of the integrated mineral mining in Northern and Northeastern Russia are discussed in terms of complex concurrent development of the territories by means of creating a single infrastructure for a number of mines, including mines which extract minerals of different types.
Thermoelastic state during electrofusion welding of polyethylene pipes at different ambient temperatures
Authors: Starostin NP , Tikhonov RS
Published: February 2022

The problem of welding polyethylene pipes used in the mining industry at low ambient temperatures is considered The numerical solution of a thermoelastic problem revealed the distinctive features of thermal and stress-strain states of weld connections of polyethylene pipes using embedded heater couplings at different ambient temperatures. It is found that in low-temperature conditions, the size of the melted zone is considerably smaller than during welding at permissible temperatures. In this regard, the pressure insufficient for high-quality welding is created between the coupling and the pipe. It is also shown that at the time of melt crystallization, the maximum values of stresses and strains during welding at low temperatures are higher than during welding in the permissible temperature range, which causes high values of residual stresses. The results obtained can be used in the development of low temperature welding technology.
Justification of the CRIRSCO standards and JORC Code for mineral resources and reserves in high-mountain regions
Authors: Bespalov DA
Published: February 2022

The article discusses the CRIRSCO and JORC international reporting standards for the transition to the JORC Code in evaluation of mineral resources in the Kyrgyz Republic.
The change in physical and mechanical properties of rocks in the course of mining in Makmal Mine
Authors: Usenov KZh , Kuvakov SZh , Alibaev AP , Kuvakov ZhM , Takeeva AR
Published: February 2022

The geological structure of the Makmal deposit composed of metamorphic, sedimentary and intrusive rocks is discussed. The physical and mechanical of rocks ((granites, marbles, silicified ore bodies, marbled limestones, carbonate breccia, quartz-feldspar, etc.) are analyzed. The physical and mechanical properties of rocks sampled in galleries 6 and 11 in Makmal Mine are tested at a laboratory scale.
Experimental study of pneumatic impact mechanism with three pneumatic chambers
Authors: Vanag YuV
Published: February 2022

The problems of preserving the performance of pneumatic impact machines while reducing their weight and dimensions for carrying out the construction works in a confined space were considered. The results of calculating the dynamics of two variants of impact devices with two and three pneumatic chambers were presented. It was shown the reserve for increasing the impact power is a raise the frequency of impacts due to more number of pneumatic chambers at the same radial dimensions and threshold impact energy of the impact devices under consideration.
Limit load in the problem of penetration of a wedge-shaped tool into the rock mass
Authors: Chanyshev AI
Published: February 2022

The problem of penetration of an absolutely rigid round cone shaped indenter into a weighted rock (an axisymmetric plasticity problem) is being solved. Limit load, depending on the angle of internal friction of the rock, adhesion, angular opening at the top of a cone, rock weight, is determined. The dependence of loading on these parameters is given.
Determining deviation parameters when sinking horizontal wells in soil
Authors: Danilov BB , Rechkin AA
Published: February 2022

A schematic diagram of a device for deflecting a hole trajectory during horizontally directed auger drilling is proposed. The problem of deflector interaction with soil under static loading is considered. Using modified Cam Clay model for clay soils of the Ansys finite element package, the parametric problem on determining the dependence of well axis deflection angle and the value of well deviation per running meter of its length on the bevel angle of the front plane of rock cutting tool is solved. The optimal value of the angle is calculated.
Blade crown design for high-speed axial mine fans
Authors: Kosykh VP , Krasyuk AM , Russky EYu
Published: February 2022

The authors propose the aerodynamic designs for the high-rate axial main mine fans having the load capacity of 696-914 kW/m2, which is 4-5.3 times higher than the currently manufactured axial fans have. This result is achieved through the increased blade tip speed up to 220 m/s owing to the topological optimization of the material distribution within the physical volume f the blade by the minimum mass criterion. The new blades have an oriented structure and mass 50-70% less than the masses of the single-piece blades at the same allowable stresses and strains.
Automatic liquid flow controller for hydraulic drilling machine
Authors: Vasiliev VB , Muslimov AP , Vasiliev VA
Published: February 2022

The procedure for conducting scientific experiments in the development of an automatic flow regulator with hydraulic control is considered. The necessity of using automatic systems in the drilling process is proved. The results of experimental studies of liquid flow regulator, namely its output characteristic and oscillograms of hydraulic motor acceleration under various operating modes are presented.
Blasting impact on underground openings in Magnezitovaya Mine
Authors: Kutuev VA , Menshikov PV , Zharikov SN
Published: February 2022

The authors assess blasting-induced seismic impact on underground openings in Magnezitovaya Mine, determine seismic stability and adjacent rocks and calculate safe distance of blasting based on the criterion of allowable seismic loads. The blasting impact testing was carried out using seismic recorders Uran and Minimate Plus with three-component seismic receivers. It is recommended on setting limiting mass of explosive per delay interval in underground blasting.
Simulation model of a hydro-impact system with two limiters of striker movement
Authors: Gorodilov LV , Pershin AI
Published: February 2022

A simulation model of a one-way self-oscillating hydro-impact system with two limiters of striker movement has been developed. The system includes a pump (a constant flow source), a striker (piston) and a housing (with limiters) connected by a mechanical spring, a spool valve, a gas-liquid accumulator, and connecting hydraulic lines. By comparing the results of calculations on the simulation model with the results of calculations on the ideal model (without hydraulic and mechanical losses and with instantly switching valve), the developed model was verified. Calculations of the working modes of reverse hydro-impact devices with an impact energy of 80 and 160 J were performed, their parameters were determined, and the real geometry of the devices was evaluated. The equipment being developed can be used to overcome jamming of equipment during drilling and using of special equipment in drilled holes, and driving holes by impact method in ground.
Patent and information analysis of evaluating the development level of technical solutions for gold heap leaching from technogenic raw materials in the cryolithzone
Authors: Myazin VP , Sokolova ES , Ardanaeva SA
Published: February 2022

An analysis of the development level of physical and chemical gold heap leaching geotechnology, used by leading gold mining countries, has been carried out with the use of the patent-information analyses of technical solutions. Based on the use of the existing information, a comparative quantitative evaluation of technical solutions for the objects of the invention at two modes of leaching (seasonal and year-round) is given.
Modeling of hydraulic fracture in a medium containing a hollow inclusion
Authors: Azarov AV , Serdyukov SV , Patutin AV
Published: February 2022

In this work, the problem of the development of a hydraulic fracture crack near a circular cavity in a three-dimensional homogeneous elastic medium is considered. The results of numerical calculations performed using the extended finite element method (XFEM) implemented in the ABAQUS software package are presented. Various variants of the position of the initial disk crack relative to the cavity are considered. Some regularities of the development of a three-dimensional hydraulic fracture near the cavity have been found.
Technological and environmental features of heap leaching of Delmachik gold-bearing ores deposit
Authors: Razmakhnin KK , Vasiljuk PA
Published: February 2022

The problem of gold ores hydrometallurgical processing with using sodium cyanide is evaluated. The prospects for the development of the use of cyanide-free reagents for leaching gold from ores are studied. The possibility of introducing a cyanide-free environmentally friendly reagent instead of the widely used sodium cyanide was determined. The results of experimental studies on the comparability of the processing of gold ores using sodium cyanide and a reagent based on sodium cyanoate are obtained. The optimal parameters of the technological process for the extraction of gold from ores using a cyanide-free reagent are established.
Shock wave analysis: A case-study of Magnezitovaya Mine
Authors: Menshikov PV , Kutuev VA , Zharikov SN
Published: February 2022

The article presents the studies into the impact of shock waves induced by underground blasting. The instrumental measurement of actual pressures at the shock wave front in air in Magnezitovaya Mine during blasting is performed. Using the measurement data, the safe distances of shock wave impact out of possible personnel injury risk are determined. The excess pressure at the shock wave front in mine air is calculated with regard to local pressure losses. The calculated excess pressures are compared with the maximum allowable pressures for personnel, timber cofferdams, ventducts, appliances and power lines.
Method of studying the movement of the impact device case in the well taking into account the reaction of the rock massif
Authors: Gorodilov LV , Efimov VP , Sazhin PV , Kudryavtsev VG , Pershin AI
Published: February 2022

Abstract A technique of experimental study of the movements of the impact device case in the well has been developed, including the use of “low-frequency” (current-vortex) displacement sensors and “high-frequency” (accelerometers) acceleration sensors. After registration, software signal processing was performed, including double integration of accelerations and determination of points of interface of displacements obtained after integration and direct registration. Oscillograms of measurements at different values reaction from the rock mass are given. The quantitative aspects of the phenomenon are discussed, and an attempt is made to identify the relationship between the quantitative indicators of impact pulses and the movement of impact device body.
Icephobic approach on hierarchical structure polymer thin-film
Authors: Hanh Vu Thi Hong , Chi Do Thuy , Ha Chu Viet , An Pham Mai , Thi Minh Thuy Nguyen , Thi Trang Bui , Mai Dam Thanh , Sonemany Souphaphone , Nguyen Thanh-Binh
Published: February 2022

In this study, we emphasised the anti-icing effects of the two-scale structure fabricated on Ecoflex thin film in several criteria for icephobic applications. The functional thin film was achieved by combining the low surface tension lubricant with a hierarchical structure, which was generated by the dry ion etching method. The anti-icing performance including adhesion strength, ice repellency, and durability was then compared with as-received substrate and non-slippery surface to demonstrate the superiority of two-scale texture in all mentioned criteria. The slippery hierarchical thin film exhibited outstanding performance with extremely low ice-surface adhesion strength, high ice repellency, and durability. This offers a new facile approach and proposed a unique design for icephobic applications such as wild shields, smart devices, cooling systems, and other outdoor equipment
Synthesis, characterization, and in vitro DPPH radical scavenging assay study of PEG-capped carbon nanoparticles derived from Butea monosperma flower extract
Authors: Das Arijit , Prabhu M P Taraka , Sarkar Nandini
Published: February 2022

In this work, the core carbon nanoparticles (BM CNs) and polyethylene glycol 400 (PEG400)-capped BM CNs were synthesised from Butea monosperma flower extract via the facile direct heating method. They were investigated for their intriguing properties and in vitro antioxidation activity in comparison with Carica papaya seed (CPS) extract via DPPH assay. The CNs were characterised by DLS, XRD, HR-TEM, TGA, FT-IR, UV–vis spectral analysis and quantum yield measurement. The PEGylated CNs demonstrated decent quantum yield, favourable size, and turbostratic carbon phase apart from better stability and dispersion nature as compared to the uncapped entity. The mildly stable uncapped sample with zeta potential −17.9 mV featured its extensively aggregated form, unlike the capped sample with −23.0 mV zeta potential, which sheds light on its enhanced stability by PEG400. Antiradical capacities of the CNs in comparison with CPS extract demonstrated the PEG400-bound nanomaterial of its superior antiradical activity against the other two controls. This study provides an insight into the novel polymer-CNs’ potent antioxidant property which can be further explored for its incorporation in targeted drug delivery and other biomedical applications.
Mapping the complex refractive index of single layer graphene on semiconductor or polymeric substrates at terahertz frequencies
Authors: Pistore Valentino , Balci Osman , Zhang Jincan , Schinde Sachin M , Meersha Adil , Ferrari Andrea C , Vitiello Miriam S
Published: February 2022

Assessing experimentally the main optical parameters of graphene (e.g. complex refractive index, carrier density, mobility) in the far-infrared (0.1–10 THz) is important for quantum science, due to the possibility to devise miniaturized devices (frequency combs, random lasers), components (optical switches, spatial light modulators, metamaterial mirrors and modulators) or photonic circuits, in which graphene can be integrated with existing semiconductor technologies to manipulate their optical properties and induce novel functionalities. Here, we combine time domain terahertz (THz) spectroscopy and Fourier transform infrared spectroscopy to extract the complex refractive index of large (∼1cm2) area single layer graphene on thin (∼0.1-1 µm) polymeric suspended substrates, flexible and transparent films, and high reflectivity Si substrates in the 0.4–1.8 THz range. We model our data to extract the relevant optical (refractive index, absorption coefficient, penetration length) electronic (Fermi velocity) and electrical (carrier density, mobility) properties of the different graphene samples.
A new method for assessing the structural safety of refractory ceramics based on a three-factor comprehensive criterion
Authors: Chen Guobing , Yang Feiyue , Zhao Shuang , Yang Zichun , Chen Jun
Published: February 2022

Traditional structural safety criteria are difficult to apply in assessing the structural safety of refractory ceramics. Herein, a three-factor comprehensive criterion for structural safety assessment of high-temperature refractory ceramics is proposed based on the failure mechanism of refractory ceramics. For the critical temperature difference criterion, the temperature of refractory ceramics changes sharply (530 °C) after the boiler stop for 120 s. Correspondingly, the left critical crack length is found to be 21 μm and the crack finally propagates to 10.87 cm (with a crack density of N = 1 cm−3) under thermal shock. For strength attenuation criterion, the cracks initiate when the compressive and tensile stress values caused by thermal shock exceed the inherent strength of refractory ceramics. Hence, the average stress of 20 MPa can be selected as the applied stress level, where the calculated life of refractory ceramics is comparable to the actual life. For the stress intensity factor criterion, the stress intensity factor (K

I
) increases with the increase of crack depth (a) and crack length (c) during crack propagation, but it decreases when a and c increase to certain values. These results reveal that the three-factor comprehensive criterion is highly applicable in analyzing the failure of refractory ceramics, providing support for the maintenance decisions during practical applications.
Study on the characteristics of non-Maxwellian magnetized sheath in Hall thruster acceleration region
Authors: CHEN Long , AN Yuhao , SUN Shaojuan , DUAN Ping , JIANG Borui , YANG Yehui , CUI Zuojun
Published: February 2022

The secondary electron emission (SEE) and inclined magnetic field are typical features at the channel wall of the Hall thruster acceleration region (AR), and the characteristics of the magnetized sheath have a significant effect on the radial potential distribution, ion radial acceleration and wall erosion. In this work, the magnetohydrodynamics model is used to study the characteristics of the magnetized sheath with SEE in the AR of Hall thruster. The electrons are assumed to obey non-extensive distribution, the ions and secondary electrons are magnetized. Based on the Sagdeev potential, the modified Bohm criterion is derived, and the influences of the non-extensive parameter and magnetic field on the AR sheath structure and parameters are discussed. Results show that, with the decrease of the parameter q, the high-energy electron leads to an increase of the potential drop in the sheath, and the sheath thickness expands accordingly, the kinetic energy rises when ions reach the wall, which can aggravate the wall erosion. Increasing the magnetic field inclination angle in the AR of the Hall thruster, the Lorenz force along the

x

direction acting as a resistance decelerating ions becomes larger which can reduce the wall erosion, while the strength of magnetic field in the AR has little effect on Bohm criterion and wall potential. The propellant type also has a certain effect on the values of wall potential, secondary electron number density and sheath thickness.
Comparative analysis of single- and multiple-frequency thermal wave radar imaging inspection of glass fiber reinforced polymer (GFRP)
Authors: Liu Lishuai , Mandelis Andreas , Melnikov Alexander , Wang Liming
Published: February 2022

Active infrared thermography has gained increasing popularity for nondestructive testing and evaluation in various industrial fields, especially for composite structures. In this regard, thermal wave radar (TWR) imaging is recognized as the next-generation active thermography technology to obtain great resolution and depth range over the inspected objects. A critical aspect concerns the optimal test parameter selection to guarantee reliable quality assurance required for industrial products. In this work, single- and multiple-frequency TWR was investigated in a quantitative manner with the goal of optimizing the detection parameters in terms of probing range and lateral and depth resolution. The effects of test parameters, including sampling frequency, modulation frequency, chirp duration, chirp bandwidth, etc, were investigated in detail through experiments on a glass fiber reinforced polymer specimen with multi-scale diameter-to-depth ratio defects. This paper aims to help yield a better understanding of the physical mechanism behind TWR and propose a workable scheme for testing parameter selection in practical applications.