bluuebunny/crossref_metadata_2025 huggingface dataset:
Materials Selection and Tests for Precise Execution of Foundry Molds Designed to Geopolymer Casts
Authors: Łopata Kinga , Korniejenko Kinga , Azzopardi Brian , Łach Michał
Published: October 2020

The paper presents the results of research on the selection of material for molds intended for geopolymer castings as well as an appropriate technological process for the preparation of such castings. Three silicons with different elasticity and hardness of 30, 40 and 60Sh were tested. The above-mentioned rubbers were used to make one-piece open molds and test the performance of each material. A model having several details and a small flat surface was chosen for the replica. Based on this variation in the wall structure, it was possible to assess the accuracy of mapping, both small elements and straight cast planes. In the prepared forms 10 tests of geopolymer casting were carried out to develop the best technological process. The appropriate result was achieved when the molds covered with the divider were flooded with raw material by vibrating them on a vibrating table, and then allowed to react for an hour for free mass components and leaking gases to the surface. After a set time, the compaction was carried out again to more accurately eliminate the resulting air bubbles. The effect of this method is to obtain a cast with precisely mapped details and a smooth even surface, and almost complete elimination of air bubbles from representative surfaces.
Ecological and technological effects of using concretes with low Portland clinker
Authors: Ostrowski Mikołaj , Pichniarczyk Paweł , Kądzielawski Grzegorz
Published: October 2020

Concrete with a low Portland clinker content involves the use of mineral additives as a cement component or as a additive in a concrete mix. The main factors influencing the increasing use of mineral additives in concrete technology are the advantageous development of the functional properties of the concrete mix, hardened concrete and a large impact on the ecological effects, including reduction of CO2 emissions. The use of concrete with a low Portland clinker content is part of the strategy for sustainable development of the economy. This paper describes the technological and ecological effects of using silica fly ash and granulated blast furnace slag additives in concretes with a low Portland clinker content. The cement and concrete additives used were mechanically activated, which allowed to reduce the content of Portland clinker in concrete. A new generation superplasticizer was used in the research, enabling a low water-cement ratio to be obtained. The mechanical properties and ecological effects of the production and use of concretes with a low content of Portland clinker were determined, including the reduction of CO2 emissions. Test results confirmed the very good mechanical properties of concrete with a high content of mechanically activated mineral additives. The research also showed an average of 3 times lower CO2 emissions compared to reference concretes made of CEM I Portland cement without additives.
Functionality and durability of anti - graffiti - systems on concrete
Authors: Jäntsch Sandra , von Laar Claudia , Bombeck Henning
Published: October 2020

Property damage and vandalism through illegal graffiti can be found worldwide. As graffiti increased, so did the interest in proper removal and the possibilities of a high-quality protection system. Anti- graffiti systems (AGS) can be used to protect objects and buildings from damage caused by graffiti. At present, AGS is still recommended for use in unspecified areas for plastics, metal, wood, brick, concrete and natural stone. In practice, it has turned out that no AGS is suitable for all surfaces. A specific reference to surface quality and properties is missing. For graffiti protection, however, the surface properties are of particular importance. They influence the liability of the AGS on the one hand and the removability of the graffiti on the other. This study is intended to demonstrate the extent to which concrete types and surfaces influence the functionality and durability of permanent AGS. This paper presents first results of practical tests on 180 concrete test specimens after currently one year of outdoor weathering. The results from three years of weathering are to be used to conclude the study for the development of an evaluation concept. Matching surfaces and AGS, with focus on the surface properties should be defined.
Microscopic analysis of the alkali-silica reactivity of various origin fine aggregate
Authors: Antolik Aneta , Jóźwiak-Niedźwiedzka Daria , Dziedzic Kinga , Bogusz Karolina , Glinicki Michał A.
Published: October 2020

Alkali silica reaction (ASR) is a harmful phenomenon occurring as a result of chemical interactions between sodium and potassium hydroxides in the pore solution and reactive minerals contained in the aggregate. Reactive minerals like microcrystalline, cryptocrystalline or strained quartz dissolve in the alkaline solution and form an expansive gel product. Proper selection of concrete constituents is necessary to ensure the durability of concrete structures. The proper recognition of the aggregate mineralogical composition is a very important element in the process of selection of concrete components due to the risk of ASR occurrence. This paper presents the results of detailed microscopic analysis of alkali-silica reactivity of domestic fine aggregates of various origins. Six siliceous sands from different locations in Poland and one limestone sand were tested. Detailed petrographic analysis was performed on thin sections. In all siliceous sands micro- and cryptocrystalline quartz was recognized as a reactive mineral. Digital image analysis was performed for quantitative assessment of the potential of reactivity of sands. It revealed, that siliceous river sands were the most susceptible to an alkali-silica reaction, which was confirmed by mortar bar expansion test performed according to the standard test method.
Micromechanical modelling of damage induced by delayedettringite formation in concrete
Authors: Yammine Alexandre , Bignonnet François , Leklou Nordine , Choinska Marta
Published: October 2020

A multi-scale poromechanical model of damage induced by Delayed Ettringite Formation (DEF) as a consequence of progression of micro-cracks at the fine aggregate scale is developed. The aim is to link the DEF-induced expansion at both the microscopic and macroscopic scales to the loss of stiffness of the mortar and the increase of its diffusion coefficient. At the microscopic scale, mortar is assumed to be constituted of three phases: cement paste, sand and micro-cracks. Damage is assumed to be driven by a free expansion of cement paste due to ettringite crystallization pressures in small capillary pores, at a lower scale. The corresponding homogenised poroelastic properties are estimated along with the diffusion coefficient by resorting either to a Mori-Tanaka scheme or to a self-consistent scheme, as a function of paste and aggregate properties as well as on the density of micro-cracks. The latter is assumed to be an evolving internal variable in order to model DEF-induced damage in the mortar. As the DEF-induced expansive free strain in the cement paste is restrained by the sand particles, internal stresses arise in the mortar. The corresponding free energy can be partially released by an increase in the micro-cracks density by analogy with the energy restitution rate of linear elastic fracture mechanics. The role of the damage criterion adopted on the thermodynamic force associated with micro-cracks density increase is investigated.
A comparative study on the effect of different activating solutions and formulations on the early stage geopolymerization process
Authors: Alves Lais , Leklou Nordine , de Barros Silvio
Published: October 2020

Concrete is a major construction material that produces high levels of carbon dioxide in its manufacturing process. Hence the construction sector is responsible for relevant environmental impacts. This justifies the need to find materials as green and ecological alternatives to common Portland cement. Geopolymers represent the most promising alternative due to its proven durability, mechanical and thermal properties. This study investigates the effects of solid-to-liquid and alkali activator ratios on the synthesis of slag-based pure geopolymer and their relation to the geopolymerization process. Two activating solutions were used: a) a mixture of sodium hydroxide, sodium silicate, and water; and b) a mixture of potassium hydroxide solution, potassium silicate, and water. As precursor material, ground blast furnace slag was used. Precursors and activators were mixed with solid-to-liquid ratios in range of 1.5 to 2.2. In the first stage of the study, the mechanical properties were evaluated for each activating solution. In the following stage, different formulations, with variations in the water percentage and solid-to-liquid ratio were tested for mechanical properties and SEM observations. Test results indicate that the resulting geopolymer has the potential for high compressive strength and is directly affected by the composition of the activating solution. It can also be observed that compressive strength was affected by solid-to-liquid ratio and % of water added to the mixture, and strength increased with ageing day.
Chilean Construction Institute: building consensus in coordinating common issues
Authors: Pfenniger Francis
Published: October 2020

The twenty years of research experience of the Chilean Construction Institute (IC) to promote “public and private efforts to improve quality, productivity and sustainability in construction” are presented in this paper. IC is a non-profit organisation formed by some public, private and academic actors: two ministries, two universities (Universidad de Chile and Universidad Católica de Chile) the Chilean Construction Chamber, three guilds (Architects, Builders and Engineers) and private industries (from the materials sector) formed this very atypical organisation back in the nineteen-nineties. The IC is a transverse association in which the actors meet freely to discuss issues that affect the construction sector, trying to find common proposals to contribute regarding the development of the country. Important actions have been developed, such as the Chilean isolation regulation; the social housing pathologies study; the National Construction Norms Council; the Chilean construction norms site; the public buildings case study; the CES - Chilean building certification system; the digitalisation of the building authorization system (on the municipal level); the Regional Seismic Code (for all Latin American and Caribbean countries) and others impossible to include here. This effort has proved to be effective and efficient in order to promote regulation upgrading and conduct studies that would otherwise be difficult to do. An interesting case is the thermal isolation regulation: with the support of the academic world, it was possible to agree a common starting point which, at the beginning, was strongly opposed by some actors. This updated regulation has proven that this public-private and academic joint venture is reliable and effective. Two cases are discussed in detail in this document.
Sprung mass positioning by semi-actively controlled damper
Authors: Jeniš Filip , Mazůrek Ivan
Published: October 2020

Recently, the intensive wear of rails, especially in curves of small radii and at switches, has been studied. The wear is caused by the high lateral force peak of the wheel against the rail when entering the curves. An effective solution for reducing undesirable lateral forces on the rail is to rotate the vehicle bogie in the direction of the rail curve, which influences the distribution of lateral force over the first and second wheelset. This reduces the force peak and thus the track wear. The bogie rotation is nowadays realized by actuators, which replace the yaw dampers. However, actuator implementation is complicated, expensive, energyintensive and demanding for the performance of a fail-safe system. From this point of view, a semi-actively controlled yaw damper appears to be a better candidate. An algorithm such as Skyhook can hold the sprung mass in the desired position. It is believed to be possible to rotate the vehicle bogie by the special S/A control strategy of a yaw damper. This paper deals with the possibilities and limits of the positioning of the sprung mass by the semi-actively controlled damper. It has been shown that the system relative attenuation and the damper response time have the greatest influence on the mass positioning efficiency.
Aminosäuren – Essenziell zum Leben
Authors: Meyer Alfons
Published: October 2020

Aminosäuren sind biochemisch Aminocarbonsäuren. Neben der Säureamidreaktion der Aminosäuren untereinander zur Bildung von Peptiden (z. B. Glutathion) und Proteinen ermöglichen ihre reaktiven Gruppen, wie die Amino- und Carboxylgruppe, weitere lebenswichtige biochemische Reaktionen. So führt die Decarboxylasereaktion zu den bedeutenden biogenen Aminen, die Abtrennung der Aminogruppe zur Bildung der α-Ketosäuren, die Transaminierung zur Bildung neuer Aminosäuren und die Reaktion mit einer weiteren Aminogruppe zur Amidbildung. Aminosäuren und ihre Folgeprodukte erfüllen vielfältige Funktionen im Organismus, z. B. als Neurotransmitter, im antioxidativen Schutz und bei der Entgiftung toxischer Substanzen. Therapeutische Einsatzgebiete sind u. a. chronisch entzündliche Darmerkrankungen, Herzrhythmus- und Schlafstörungen sowie Burnout.
N-Acetyl-Cystein – Nur ein Mukolytikum?
Authors: Gröber Uwe
Published: October 2020

Durch die Spaltung von Disulfidbrücken wirkt N-Acetyl-Cystein (NAC) mukolytisch bei Atemwegs-/Lungenerkrankungen und greift die Hülle von SARS-CoV-2 an, wodurch die Infektiosität des neuen Coronavirus abgeschwächt wird. Als Gluthation-Prodrug hat die Substanz zentrale Bedeutung für Immunfunktion, Regulation der Stickstoffbilanz und Erhalt immunkompetenter Zellmasse. In einer Studie konnte eine Verbesserung der Überlebenszeitprognose von AIDS-Patienten unter NAC-Therapie belegt werden. Kardioprotektive Wirkung zeigt N-Acetyl-Cystein bei endothelialer Dysfunktion und Homocyst(e)inämie. Zudem konnte die Gabe von NAC in einer Studie kontrastmittelinduzierte Nierenschäden reduzieren.
The Impact of Obesity on the Management and Outcomes of Postpartum Hemorrhage
Authors: Polic Aleksandra , Curry Tierra L. , Louis Judette M.
Published: October 2020

Objective The study aimed to evaluate the impact of obesity on the management and outcomes of postpartum hemorrhage.

Study Design We conducted a retrospective cohort study of women who delivered at a tertiary care center between February 1, 2013 and January 31, 2014 and experienced a postpartum hemorrhage. Charts were reviewed for clinical and sociodemographic data, and women were excluded if the medical record was incomplete. Hemorrhage-related severe morbidity indicators included blood transfusion, shock, renal failure, transfusion-related lung injury, cardiac arrest, and use of interventional radiology procedures. Obese (body mass index [BMI] ≥ 30 kg/m2) and nonobese women were compared. Data were analyzed using Chi-square, Student's t-test, Mann–Whitney U test, and linear regression where appropriate. The p-value <0.05 was significant.

Results Of 9,890 deliveries, 2.6% (n = 262) were complicated by hemorrhage. Obese women were more likely to deliver by cesarean section (55.5 vs. 39.8%, p = 0.016), undergo a cesarean after labor (31.1 vs. 12.2%, p = 0.001), and have a higher quantitative blood loss (1,313 vs. 1,056 mL, p = 0.003). Both groups were equally likely to receive carboprost, methylergonovine, and misoprostol, but obese women were more likely to receive any uterotonic agent (95.7 vs. 88.9%, p = 0.007) and be moved to the operating room (32.3 vs. 20.4, p = 0.04). There was no difference in the use of intrauterine pressure balloon tamponade, interventional radiology, or decision to proceed with hysterectomy. The two groups were similar in time to stabilization. There was no difference in the need for blood transfusion. Obese women required more units of blood transfused (2.2 ± 2 vs. 2 ± 5 units, p = 0.023), were more likely to have any hemorrhage-related severe morbidity (34.1 vs. 25%, p = 0.016), and more than one hemorrhage related morbidity (17.1 vs. 7.9, p = 0.02). After controlling for confounding variables, quantitative blood loss, and not BMI was predictive of the need for transfusion.

Conclusion Despite similar management, obese women were more likely to have severe morbidity and need more units of blood transfused.

Key Points
Photoacoustic spectroscopy: Trace CO detection by using 10 mW near-infrared laser and cantilever beam
Authors: Cheng Hongtu , Zhang Xiaoxing , Bian Chao , Cheng Jun , Chen Zhenwei , Zhang Yin , Tang Ju , Xiao Song
Published: October 2020

Sulfur hexafluoride (SF6) is commonly used in gas insulated switchgears (GIS) as an insulating medium. When local overheating or partial discharge occurs in GIS, SF6 may be decomposed into various products including CO. In this paper, based on the photoacoustic (PA) effect of gas molecules, the infrared absorption line at 6380.318 cm−1 was chosen as the target line. An infrared laser with a center wavelength of 1567 nm was chosen as the light source, and a cantilever enhanced PA detector was used as the sensor; then, the experimental platform was constructed. The influence of the temperature and pressure on the infrared absorption coefficient of CO was analyzed. The relationship of the PA signal and the CO concentration under the background of SF6 and N2 were obtained. The results show that the temperature has a great influence on the CO absorption coefficient while the influence of pressure is negligible, and the temperature influential coefficient is about 5.0 × 10−6 cm−1/°C. The detection system has the highest signal-to-noise ratio when the frequency of the chopper is 40 Hz. Under N2 and SF6 background gases, there is a good linear relationship between CO concentration and pure PA signals. The minimum detection limit of CO in the background of N2 is 3.63 ppm, while it is 9.88 ppm in SF6. The different kinds of the background gases can influence the PA signals. The PA signals decrease with the increase of the temperature of the gas cell, and they also decrease with the increase of the pressure.
Revealing the magnetic properties in a double-perovskite thin film
Authors: Frank Jodi Ackerman
Published: October 2020

The magnetism is dependent on the crystal structure orientation and the extent of ionization of B-site ions affected by strain.
C4F7N holds promise as an environmentally friendly electrical insulation gas
Authors: Bandari Anashe
Published: October 2020

Understanding how C 4 F 7 N decomposes is a necessary step for determining its applications to large-scale power equipment.
Spectral solar irradiance on inclined surfaces: A fast Monte Carlo approach
Authors: Li Mengying , Liao Zhouyi , Coimbra Carlos F. M.
Published: October 2020

Estimating spectral plane-of-array (POA) solar irradiance on inclined surfaces is an important step in the design and performance evaluation of both photovoltaic and concentrated solar plants. This work introduces a fast, line-by-line spectral, Monte Carlo (MC) radiative transfer model approach to simulate anisotropic distributions of shortwave radiation through the atmosphere as photon bundles impinge on inclined surfaces. This fast Monte Carlo approach reproduces the angular distribution of solar irradiance without the undesirable effects of spatial discretization and thus computes detailed POA irradiance values on surfaces at any orientation and also when surfaces are subjected to the anisotropic ground and atmospheric scattering. Polarization effects are also easily incorporated into this approach that can be considered as direct numerical simulation of the physics involved. Here, we compare our Monte Carlo radiative transfer model with the most widely used empirical transposition model, Perez4, under various conditions. The results show that the Perez4 model reproduces the more detailed Monte Carlo simulations with less than 10% deviation under clear skies for all relevant surface tilt and azimuth angles. When optically thin clouds are present, observed deviations are larger, especially when the receiving surface is strongly tilted. Deviations are also observed for large azimuth angle differences between the receiving surface and the solar position. When optically thick clouds are present, the two models agree within 15% deviation for nearly all surface orientation and tilt angles. The overall deviations are smaller when compared with cases for optically thin clouds. The Perez4 model performs very well (∼6.0% deviation) in comparison with the detailed MC simulations for all cases, thus validating its widespread use for practical solar applications. When detailed atmospheric profiles and cloud optical properties are available, the proposed fast Monte Carlo radiative model reproduces accurate spectral and angular POA irradiance levels for various atmospheric and cloud cover conditions, surface orientations, and different surface and ground properties.
Floating GaN whispering gallery mode micro-ring lasing with Burstein–Moss effect
Authors: Zhu Gangyi , Fang Ming , He Siqing , Qin Feifei , Yang Xuelin , Wang Yongjin , Xu Chunxiang
Published: October 2020

A floating GaN micro-ring is fabricated by standard semiconductor technology. Under pump power conditions, ultraviolet lasing with a quality factor of 3600 is obtained. Resonant mode analysis indicates that the lasing spectra contain two types of whispering gallery modes and one type of Fabry–Perót mode. With the increase in pumping power, the state filling induced Burstein–Moss effect is observed and understood through synchronous measurement of photoluminescence and time resolution photoluminescence spectra.
Structural damage identification based on the method of generalized uniform load surface curvature
Authors: Zhao Jiangang , Zhang Yuxiang , Chen Jiazhao , Zhang Xin
Published: October 2020

In view of the fact that the lower-order structural modes can be obtained easily in practice and the structural parameters before damage are unknown, the generalized uniform load surface curvature method based on least squares polynomial fitting is proposed to detect structural damage. First of all, the modal flexibility curvature method and the uniform load surface curvature method derived from the modal flexibility curvature are analyzed theoretically, and then, combining with the concept of generalized modal flexibility matrix, the generalized uniform load surface curvature method is obtained, and the generalized uniform load surface curvature method based on least squares polynomial fitting is put forward finally. Second, taking the numerical simulation of a T-beam fixedly supported at both ends as an example, the damage identification effect of the four methods mentioned above is calculated and compared. The results show that the generalized uniform load surface curvature method based on least squares polynomial fitting needs only lower-order modal parameters after the structural damage, can well identify not only the damage location but also the damage degree of the single damage or the multiple damage, and presents small truncation errors. Compared to the other three methods, it has certain advantages. Finally, the damage of a T-shaped simply supported beam is identified by using the proposed method, which verifies the effectiveness of the method, and hence, this method has important practical application value.
Calling behaviour in the invasive Asian house gecko (Hemidactylus frenatus) and implications for early detection
Authors: Hopkins Jaimie M. , Higgie Megan , Hoskin Conrad J.
Published: October 2020

Abstract
ContextAcoustic communication is common in some animal groups, with an underlying function typically associated with mating or territoriality. Resolving the function of calls is valuable both in terms of understanding the fundamental biology of the species and, potentially, for applied reasons such as detection. Early detection is a key step in exclusion and eradication of invasive species, and calling behaviour can be used in this regard. The Asian house gecko (Hemidactylus frenatus) is one of a minority of lizards that uses acoustic communication. However, despite how conspicuous the call is, its function remains poorly resolved. It is also one of the world’s most invasive species, with exclusion via early detection being the key form of control.
AimsThe aim was to resolve calling patterns and underlying function of the loud, multiple-chirp call (‘chik, chik, chik…’) in H. frenatus, in the context of using the results for developing effective methods for detection of new and establishing populations.
MethodsThe calls of wild H. frenatus were recorded to assess peaks in calling activity. Also, laboratory experiments were performed to determine which individuals call, what causes them to call and the degree of call variation among individuals.
Key resultsAssessment of calling behaviour in the wild revealed greater calling activity in warmer months, and five- to 10-fold peaks in calling activity at sunset and 30min before sunrise. Laboratory experiments revealed that calls were uttered exclusively by males and primarily by adults (although juveniles can call). Males called more when they were paired with females as opposed to other males. Calls differed among geckos, including the expected negative correlation between dominant frequency and body size.
ConclusionsThe results suggest that the multiple-chirp call functions as a territory or sexual broadcast by males, perhaps containing information such as body size.
ImplicationsDetection success can be maximised by performing acoustic surveys (by human or machine) during the calling peaks at 30min before sunrise and at sunset, particularly during warm nights. However, these surveys will only be effective for detecting adult males. The results also suggest that good quality recordings could potentially be used to identify individual geckos.
Performance vs. competence in human–machine comparisons
Authors: Firestone Chaz
Published: October 2020

Does the human mind resemble the machines that can behave like it? Biologically inspired machine-learning systems approach “human-level” accuracy in an astounding variety of domains, and even predict human brain activity—raising the exciting possibility that such systems represent the world like we do. However, even seemingly intelligent machines
fail
in strange and “unhumanlike” ways, threatening their status as models of our minds. How can we know when human–machine behavioral differences reflect deep disparities in their underlying capacities, vs. when such failures are only superficial or peripheral? This article draws on a foundational insight from cognitive science—the distinction between
performance
and
competence
—to encourage “species-fair” comparisons between humans and machines. The performance/competence distinction urges us to consider whether the failure of a system to behave as ideally hypothesized, or the failure of one creature to behave like another, arises not because the system lacks the relevant knowledge or internal capacities (“competence”), but instead because of superficial constraints on demonstrating that knowledge (“performance”). I argue that this distinction has been neglected by research comparing human and machine behavior, and that it should be essential to any such comparison. Focusing on the domain of image classification, I identify three factors contributing to the species-fairness of human–machine comparisons, extracted from recent work that equates such constraints. Species-fair comparisons level the playing field between natural and artificial intelligence, so that we can separate more superficial differences from those that may be deep and enduring.
Does stress matter?
Authors: Tsiamas Athanasios , Jarema Gonia , Kehayia Eva
Published: October 2020

This study investigates the effect of stress change during compound processing in Modern Greek. Twenty-five native
speakers were tested in a cross-modal lexical decision task and a naming task in order to test for performance differences across
stress-change vs. non-stress-change compounds. No statistically significant difference was found for the lexical decision task. However, the
naming task showed a significant effect of stress change in compound processing, with the production of non-stress-change compounds showing
facilitation. These results indicate that stress change is reflected in compound processing in Greek and underscore the importance of
considering the interplay between specific tasks and the computational role of linguistic features.
Formation of flat electron density profiles at the L-2M stellarator at high ECRH powers
Authors: Meshcheryakov A I , Vafin I Yu , Grishina I A
Published: October 2020

The shapes of the electron temperature profiles were analyzed at the L-2M stellarator based on the data obtained in experiments on the axial ECR plasma heating performed at different plasma densities and heating powers. It was ascertained that, at the reduced ECRH power exceeding some threshold value, the electron temperature profiles become broadened and flat in the axial region of the plasma column. The appearance of the flat temperature profiles correlates with the occurrence of the density profiles with a dip in the axial region forming at high reduced heating powers as a result of the density pump-out effect. It was concluded that, as a result of occurrence of the density profiles with a dip in the axial region, the mechanism for the microwave radiation absorption changes. Apparently, the cyclotron absorption of the electron Bernstein waves becomes the main mechanism for the microwave radiation absorption, which, in turn, results in the occurrence of the broad and flat (in the axial region) electron temperature profiles.
Nonlinear absorption of Alfvén waves: model taking into account photorecombination radiation
Authors: Gavrikov M B , Pestryakova N V , Taiurskii A A
Published: October 2020

Damping of the Alfvén wave falling onto the boundary of the dissipative plasma is considered. In this model, the following dissipation mechanisms are included: the hydrodynamic viscosities and thermal conductivities of electrons and ions, magnetic viscosity, thermal relaxation, losses due to bremsstrahlung as well as the synchrotron and photorecombination radiations. These studies are based on the equations of the two-fluid electromagnetic hydrodynamics that fully account for the electron inertia. Numerical analysis based on the implicit finite-difference scheme indicates the existence of a quasi-stationary regime of the Alfvén wave damping in dissipative plasma and shows that the Alfvén wave can be imprisoned in plasma.
Creation of stable dust structures in the glow discharge in magnetic fields of up to 15000 G
Authors: Pavlov S I , Novikov L A , Dzlieva E S , Karasev V Yu
Published: October 2020

The dusty plasma created in the dust trap in strata of the glow discharge in the strong magnetic field was studied. The conditions were found that make it possible to avoid the development of instabilities in the glow discharge plasma in the magnetic field. For the first time, in the magnetic field range of higher than 10000 G, the dust structures were obtained. The rotational speed as a function of the magnetic field induction was studied. The experimental conditions were discussed under which the stable dust structures can be created.
The method of Г-operators and the tertiary quantization of quantum electrodynamics equations
Authors: Veklenko B A
Published: October 2020

In cases of solving the problem described by the equations of quantum electrodynamics within the second quantization formalism, it is proposed to quantize these equations one more time, and then solve this problem within the tertiary quantization formalism. In optics of the dispersive media, this procedure makes it possible to avoid the problem of the forced breaking of the photon quantum correlators and to discover many correlation effects previously unknown.
Densification of SiC from Amorphous Polysilazane with The Addition of β-SiC as a Filler Prepared by Hot Pressing Furnace
Authors: Sukmarani Galuh , Noviyanto Alfian , Kusumaningrum Retno , Muhammad Habieb Alvin , Fauzi Fiqhi , Bambang Widayatno Wahyu , Sukarto Wismogroho Agus , Ikhlasul Amal Muhamad , Taufiqu Rochman Nurul
Published: October 2020

Dense silicon carbide (SiC) was successfully sintered from amorphous polysilazane (PSZ) using hot pressing at 1750oC for 1 hour under an applied pressure of 20 MPa in Ar atmosphere. The effect of β-SiC powder as a filler on the density, phase, micro structure and hardness were examined. Al2O3 and Y2O3 were used as sintering additives through the liquid phase sintering mechanism. The phase analysis showed the formation of SiC after sintering of amorphous PSZ. However, α-SiC was a dominant phase and the amount of α-SiC decreased with the addition of β-SiC powder. The relative density of sintered SiC was obtained in range 99.6 -99.7% regardless of the addition of β-SiC powder. Sintered SiC from amorphous PSZ revealed significant shrinkage compared to sintered SiC from β-SiC powder, while the minimum shrinkage was achieved by the addition of 70% β-SiC into amorphous PSZ. However, the hardness of sintered SiC did not correlate with the addition of β-SiC powder, with highest hardness of 26.4 GPa, which is SiC from solely β-SiC powder. This result indicates that amorphous PSZ is an alternative precursor to fabricate dense SiC.
Design of Frangible Composite Production Process and Plant Layout with Powder Metallurgy Method and Capacity of 50.000.000 Rounds/Year
Authors: Widyastuti  , Sulistya F F , Pratiwi V M , Jatimurti W , Ardyananta H
Published: October 2020

Frangible composite material is one of the types of advanced material utilized by defense technology application which has been certified. In fact, this material is in development for mass production. In order to realize the mass production stage, it is necessary to have a comprehensive design on process production, specification, machine capacity and the blueprint of plant’s layout. Production process planning would be conducted by the target up to 50 million rounds per year. This process uses powder metallurgy method which consists of mixing, compaction, sintering, finishing, quality control, and packaging. This research would result various variable and constants in each processes, plant design, specification, and number of machines needed by using data from literature review and previous research. Then, the number of machines is going to be calculated in order to find the certain number of machines that are needed. The calculation implies the needed of production machines which are 1 unit of mixer, 3 units of automatic mechanical compaction machine, 1 unit of continuous sintering furnace, 1 unit of finishing machine, and 3 units of quality control machines. For the production process simulation, we use Tecnomatix Plant Simulation in order to simulate the processes to get the data. The simulation process would be started by inputting the total number of machines that are used by and the variables and constants in each process which had been determined before. By calibrating the running time for 365 days 3 hours 15 minutes, the result stated that the simulated production process produced the number of outputs of 50,037,120 rounds/year and 45,696 rounds per shift.
Reactivating Adsorption Capacities of Spent Bleaching Earth for Using in Crude Palm Oil Industry
Authors: Eko Saputro Kurniawan , Siswanti Puji , Wahyu Nugroho Dwi , Ikono Radyum , Noviyanto Alfian , Taufiqu Rochman Nurul
Published: October 2020

The spent bleaching earth from the palm oil refining industries contains various contaminants, including free fatty acids and hazardous material. The conventional procedure is harmful to the environment. In this study, spent bleaching earth (SBE) was successfully regenerated by calcination and acid-activation process. The calcination process was performed at 500, 600 and 700°C for 2, 3 and 4 h. All samples were then mixed with CaCO3 and lastly activated with aqueous acid. The results showed the SBE color restored at calcination temperature higher than 500°C, even though the decomposition of the volatile compound was removed at 680°C according to thermal gravimetric analysis. Treatment affected the clay structure and mostly removed the impregnated organic matter. The primary phase of regenerated SBE is similar to virgin bleaching earth (VBE), implying the calcination and acid-activation is not alter the phase. Moreover, the adsorbent capacity of regenerated SBE was comparable with VBE, showing the regenerated SBE has promising potential for many applications, in particular for the palm oil refining industry. Regenerated SBE gave significantly larger specific surface area, microporous surface area and total pore volume with smaller the average pore diameter.
Preparation and Structures of Carbon-Copper Oxide Nanofibers from Electrospun Polyacrylonitrile Composite
Authors: Nasir Muhamad , Ida Sugatri Rana
Published: October 2020

Carbon-copper oxide nanofibers have been prepared by heat treatment of polyacrylonitrile-copper salt nanofibers. In this study, fabrication of PAN-copper salt using two different methods - firstly, synthesis of PAN-copper salt solution using electrospinning (PAN-CuAc NF), and secondly, immersion of electrospun PAN nanofiber in the copper salt solution (PAN-c-CuAc NF). Those ways had a distinct effect on the structure of carbon-copper oxide nanofibers. The morphologies and structures of carbon-copper oxide nanofibers were observed by scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), infrared spectroscopy (IR), X-ray diffraction (XRD), and Raman spectroscopy. The SEM image showed a randomly oriented nanofiber structure without bead formation, which average diameter of the nanofiber decreased with increasing process temperature. IR spectra and XRD patterns confirmed the formation of aromatic structures and graphite-like structures on carbon-copper oxide nanofiber. The Raman spectrum revealed that the intensity ratio (ID/IG) of carbonized nanofibers showed different values when the electrospun PAN composite nanofibers were synthesized using a different method, 1.59 for electrospun PAN nanofibers (CNF), 1.92 for carbonized PAN- CuAc nanofibers (C-copper oxide NF), and 0.60 for carbonized PAN-c-CuAc nanofibers (C-c-copper oxide NF).The presence of Cu element has been successfully detected in carbon-copper oxide nanofibers using EDX analysis.
The Effect of Al2O3 Nano Particles on Characteristics of Mg-Al-5TiB Grain Refiner Composites Produced by Stir Casting Method
Authors: Zhafara Alintiya , Anne Zulfia S
Published: October 2020

High needs for light material with good mechanical characteristics made magnesium and its alloys as an alternative choice because of magnesium’s low density, 1.74 gr/cm3. However, its use is limited by its low strength and ductility. In this experiment, a fabrication process of the composite which is Mg-Al-5TiB as Matrix with the addition of Nano Al2O3 as a reinforced with volume fraction varied from 0.10 Vf-% to 0.25 Vf-% by stir casting method. The composites then were characterized by both microstructure and mechanical properties. The microstructure was analyzed by an optical microscope and scanning electron microscope link to energy-dispersive spectra to analyze the phases present in composites and confirmed by X-Ray Diffraction. The XRD shows some phases such as Mg, MgO, MgAl2O4, and B2O3. The optimum mechanical properties of composites were obtained at the addition of 0.2 Vf-% Al2O3, where the tensile strength, elongation, wear rate and impact strength were 46.1 MPa, 14%, 0.3x10-5 mm3/s, and 0.06 J/mm2. The hardness of composites was value, 40.1 HRH. The porosity maximum was found at the addition of 0.25 Vf-% with the value of 9.37% caused by nano Al2O3 particle forming clustering (porosity is related to clustered particles) and inhibiting liquid metal moving rate. The addition of grain refiner makes solidification went faster and refined the grains.
Preliminary Study of Zirconium Carbide Ceramic Deposition on Austenitic Stainless Steel by Pulsed Laser Deposition
Authors: Shabrina N. , Sumaryo  , Sugeng B. , Haerani D.N. , Mardiyanto  , Rivai A.K.
Published: October 2020

Coating Zirconium Carbide (ZrC) on the stainless steel (SS) will increase the corrosion resistance of SS which suffer from the intergranular attacks during operation as construction materials in reactors. ZrC coating have been partially deposited on Austenitic 316L SS by Pulsed Laser Deposition (PLD) at 800°C temperature substrate with constant oxygen flow injection of 40 sccm (Standard Cubic Centimeters per Minute), chamber pressure around 229-244 mTorr and 105 the numbers of laser shots. The sample was analyzed using X-Ray Diffraction (XRD), Microscope Optic (MO), Scanning Electron Microscope – Energy Dispersive X-Ray Spectroscope (SEM-EDS), and Atomic Force Microscope (AFM) to characterize the phase, morphology, thickness of the films and surface topography. The results showed that the thickness of the thin film around 4.93-8.10 µm with 49.6 nm surface roughness. The film surface was very smooth. The present of Zr and C was detected in SEM & EDS results but not appeared in XRD pattern, possibly due to diminish tension of the thin films on the substrates caused by low lattice mismatch between ZrC and Austenitic 316L SS substrate. Furthermore, ZrO2 phase has been found on the substrate which is predicted because of the interaction between ZrC target and oxygen background gas.
Hydrochloric Acid Leaching Approaches for Tantalum and Niobium Pentoxides Enrichment in 1st Tin Slag from Bangka Island
Authors: Permana Sulaksana , Abdul Majid Rafdi , Wahyuadi Soedarsono Johny
Published: October 2020

Indonesia is the second largest tin producer in the world that resulting abound of byproduct. This by-product contains some of valuable metal oxides, such as 0.30% tantalum (Ta2O5) and 0.58% niobium pentoxide (Nb2O5). The supply deficit of these minerals induces researchers worldwide to conduct investigations. This study explored the effect of roasting at 900°C, NaOH quenching, and HC1 leaching with 45, 65, and 85°C temperature variables and 4M, 6M, 8M concentration variables. These measures were employed to upgrade the contents of tantalum and niobium pentoxide (TNP). The filtration products of quenching and leaching were characterized by X-Ray Fluorescence (XRF). On the one hand, 900°C roasting and NaOH quenching decreased the 100 mesh-measuring TNP contents, 0.14% Ta2O5 and 0.2% Nb2O5. On the other hand, HC1 leaching with a 65°C temperature variable showed an optimal yield ratio of 3.75 Ta2O5 and 3.57 Nb2O5. The total yield ratio of TNP is 3.63.
Synthesize & Characterization of Li3PO4(0.5)LiI(0.25)LiCl(0,25) Solid Electrolyte for Lithium Ion Battery
Authors: Paksi Raganata Gde , Kartini Evvy , Jodi Heri , Wahyudianingsih  , Sudjatno Agus , Nicolas Gunawidjaja Philips
Published: October 2020

Lithium phosphate (Li3PO4) is a promising candidate for solid electrolytes. However its ionic conductivity still stands at 3 × 10−7 S/cm which is very low compared to liquid electrolytes which are contained within widely distributed lithium ion batteries at 10−3 S/cm. This requires a solution to increase its conductivity which is the addition of dopants. The proposed dopants are lithium iodide (LiI) and lithium chloride (LiCl) which is mixed with the Li3PO4, creating the new solid electrolyte system Li3PO4(0.5)LiI(0.25)LiCl(0,25). The mixture had an ionic conductivity of 8 × 10−4 S/cm observed through electrochemical impedance spectroscopy (EIS). The crystal structure observation using x-ray diffraction identified the Li3PO4 belongs to the Hermann-Mauguinn symmetrical space group of P m n b.
GOF-SLFN- An Intelligent Attack Detection System against Denial of Service (DoS) attacks based on Glow Worm Swarm optimized Single Layer Feed Forward Networks for vehicular Cyber Physical Systems (VCPS)
Authors: Mercy Sam Sigamani Rama , Ganapathi Padmavathi
Published: October 2020

Vehicular cyber-physical network use either wireless communications or internet to communicate with each other for an efficient data transfer. Data includes transportation details, safety, mobility and sustainability. However, these communication networks for vehicular transportation are susceptible to different cyber-attacks, which may lead to severe damages or huge casualties in vehicular infrastructures. Hence the intelligent attack detection system needs to be obtaining the lime light of research based on recent machine and deep learning algorithms. In this paper, the GOF-SLFN (Glowworm optimized features for Single-layer feed-forward network) is proposed to detect the attacks among the vehicular cyber physical systems. Since DoS attacks can happen at any layer of OSI Model such as application, network and transport the foremost purpose of the paper is to detect the DoS attacks using the proposed intelligent algorithm. The glowworm algorithm extracted the optimum features based on the probabilistic mechanism and SLFN has been proposed using glowworm to detect the DoS attacks. The proposed system outperformed in detection when compared with artificial neural network, SLFN, Multi-layer Perceptron and random forest. The proposed GOF-SLFN has been again compared with firefly, Bat and Latent Dirichlet Allocation (LDA) and found the proposed intelligent system provided promising results for detection of DoS attacks in VCPS. The proposed system has been tested on the real time scenarios created with SUMO and OMNET++ environment integrated with CIC IDS 2018 datasets. The performance metrics considered were based on accuracy, sensitivity and specificity.
A Novel Approach for Improved Load Balancing and Interference Reduction in Wireless Networks using OFDMA
Authors: Saravana Kumar SS , Umapathy K
Published: October 2020

The quality of service offered to the user equipment in Multihop cellular networks with proper connection is affected severely due to the fading effects. These fading effects can lead to link loss between the user equipment (UE) and base station. This problem is severe when the UE traveling inside of tunnel, forests and big buildings. The duration of the link loss may vary from seconds to hours. Link loss management can control the link loss, increase the coverage area and signal quality in cell boundaries. It requires predictive power and link scheduling in cell sectors and signal quality enhancement at cell boundaries using filters. Interference Coordination and Load Balancing at base station and UE algorithm is used. This paper introduces a link loss management algorithm with load balancing to provide seamless service to users and this increases the Quality of Service (QoS) of safety critical communications.
Comparative review on mechanical properties of concrete with replacing curing water by self-curing compounds
Authors: Niranjan Reddy BL , Vinod Kumar M
Published: October 2020

The curing of concrete requires large amount of water. Self-curing concrete is one kind of concrete, which fix itself by holding water (dampness content) in it. A body of literature on the different self-curing compounds is uses for curing purpose without externally curing the concrete is currently available, but a systematic review is lacking. Therefore, this paper reviews the published literature on the use of different self-curing compounds in concrete and past work analysis on self-curing concrete. Various chemicals were uses to attain this curing. It was found out that various chemical admixtures like Poly ethylene glycol, Sodium lignosulphonate, Polyvinyl alcohol, Super absorbent polymer and normally accessible and regularly utilizes materials like Light weight aggregates, Wood powder and Light expanded clay aggregate were uses to fabricate self-curing concrete. This paper summarizes the collected literatures on replacement of curing water with self-curing compounds and how these affects the fresh properties and hardened (solidified) properties of concrete, furthermore, we expected that this work may advise further examination regarding the utilization of curing compounds to upgrade the properties of cement and concrete items.