bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat-exchange units with porous inserts
Authors: Stepanov Oleg , Aksenov Boris , Rydalina Natalia , Antonova Elena
Published: December 2019

Currently, porous metals are not used in heat supply systems. Usage of porous materials in heat exchangers increases the heat transfer intensity and makes the heat exchangers more compact. An experimental setup consisting of two circuits was developed in order to study the influence of porous metals on heat transfer intensity. In the first circuit the hot coolant is water, which flows through narrow tubes inside the porous metal. In the second circuit the cold coolant is freon. The purpose of the study is to obtain experimental confirmation of the hypothesis of an increase in the heat transfer intensity when using porous metals. To achieve this goal, experiments were carried out, which showed the increased heat transfer intensity. The standard methods for calculating heat exchangers cannot be applied in this case as the inner pores’ surface is unknown. A mathematical model was compiled allowing engineering calculations for the heat exchangers of this type. The hot water temperature inside the heat exchanger is determined analytically. The resulting equation allows us to determine the cooling degree of the first coolant, i.e. hot water. The obtained deviations between experimental and analytical data are within the acceptable limits, which indicates the reliability of the proposed model.
The investigation of absolute flow non-uniform velocity distributions influence at the centrifugal compressor axial radial impeller inlet using numerical calculation methods in ANSYS CFX
Authors: Rakhmanina L.A. , Zuev A.V. , Petrov A. Yu. , Aksenov A.A. , Nguyen Minh Hai
Published: December 2019

Currently, methods of numerical modelling are widely used. They are especially widely used in the design of turbo compressors. For the specific task of designing new flowing parts of a centrifugal compressor, it is not recommended to deviate from the canonical design techniques, but it is preferable to supplement them with numerical methods. This article is devoted to the end two-element stage investigation of a centrifugal compressor with an axial radial impeller; the stage main dimensions were obtained using the method of V.F. Rice. In order to obtain the necessary pressure characteristics and determine the dependence for the absolute velocity non-uniform distribution at the inlet to the axial radial impeller, the flow path main dimensions were optimized using numerical calculation methods. The calculation was performed using the SST turbulence model using computational gas dynamics methods in the ANSYS CFX software environment. Based on the optimization results, five compressor designs and corresponding characteristics were obtained. The absolute velocity distribution nature at the inlet to the centrifugal compressor axial radial impeller for five flow path variants is investigated. Empirical dependences are obtained for the deviation of the absolute velocity at the inlet in the hub section axial radial impeller and the absolute velocity deviation at the shroud from the absolute velocity at the average diameter based on the results of a numerical experiment. Recommendations are made for further absolute velocity distributions investigating at the inlet to the compressor impeller.
Expedited method of testing and refinement of refrigeration centrifugal compressors
Authors: Sukhomlinov Igor , Golovin Mihail
Published: December 2019

Currently existing regulatory documents assume that refrigeration compressors are tested as part of test rigs with heat-exchange equipment. Given the high energy intensity of centrifugal compressors, the drive power of which in cooling mode with a cold capacity of up to 8.0 MW can be 2.0 or more MW, the creation of test rigs for preliminary and acceptance tests at the manufacturer’s factory requires a large investment. An alternative to the considered refrigeration centrifugal compressors test method is a test on a test rig in which the agent is partially condensed. In this case, an evaporator and a full-sized condenser are not required. The mathematical model of the refrigeration centrifugal compressors developed by JSC VNIIKHOLODMASH, allows testing of the refrigeration centrifugal compressors in model conditions, when the entire compressor operation cycle at the test rig is carried out in the area of superheated steam. Since the refrigeration centrifugal compressors mathematical model is based on physical simulation of compression processes in model stages at different values of conditional Mach numbers, dimensionless characteristics of model stages can be used to calculate the characteristic of the created compressor when operating under new conditions. The implementation of the model test method provides reduction of testing time due to absence of phase changes of the agent, improves the accuracy of the obtained results, reduces of power consumption, simplifies the test rig, and reduces consumption of the agent for filling the rig and water for cooling the agent.
The ensemble-averaged characteristics of the bubble system during cavitation in the separator
Authors: Kapranova Anna , Lebedev Anton , Neklyudov Sergey , Melzer Alexander
Published: December 2019

The object of research is the process of formation of vapor-gas bubbles at an early stage of hydrodynamic cavitation during throttling of the liquid in the axial valve separator. Designing a separator under conditions of decreasing bubble formation intensity is an urgent problem. Based on the energy approach, a stochastic model of the formation of an energetically closed system of bubbles in the separator according to the Gibbs ensemble is proposed. Analytical dependences are obtained for the density function and the bubble geometric characteristics averaged over the ensemble, depending on the design parameters, operating parameters, and physic-mechanical properties of the working medium, including the ratio of the gas and vapor contents in the inner cavity of the bubble. The expressions for the indicated distribution function over the size of the bubbles and for the ensemble-averaged characteristics of the system of bubbles formed (diameter and surface area) can be used in the formation of an engineering methodology for calculating control equipment.
Development of the model for a diesel engine catalytic converter
Authors: Blinov Artem , Malastowski Nikolay , Myagkov Leonid
Published: December 2019

One of the key issues of the modern engine development is to comply with today’s stringent emission standards. It forces the manufacturers to enhance in-engine and after treatment emission reduction technologies continuously. The selective catalytic reduction (SCR) is still the most effective technique for nitrogen oxides removal from exhaust gases of vehicles with diesel engines. Numerical modelling is widely used for SCR systems development and assessment. In this paper, a simplified one-dimensional numerical model of diesel SCR catalyst, which was implemented in Matlab, is described. The algorithm for automatic mesh generation describing real cross-section geometry of the catalyst block and the calculation procedure allowing to take into account non-uniform distribution of the gas flow parameters at the catalyst inlet are presented. Model was validated by the experimental data available in the literature. Numerical simulations for the full-scale modern SCR catalyst were carried out. The effect of the gas velocity non-uniformity at the catalyst inlet on the overall NOx reduction efficiency was evaluated.
Principles of electricity metering in networks with non-liner load
Authors: Pudkova Tamara , Bardanov Alexey
Published: December 2019

The existing approach to electricity metering, which underlies the formation of payment for consumed electricity, has a significant drawback. It can be correctly used in systems with a sinusoidal symmetrical mode, but needs to be improved in other network modes. The article defines indicators that numerically reflect the effect of distortions on the modes of distribution electric networks, as well as indicators that take into account consumed inactive power (by analogy with reactive power in a sinusoidal mode) when paying electricity bills to an electricity supplier. The proposed principles of electricity consumption metering includes the influence of such indicators as the spectral composition of voltage and current, the ratio of linear and nonlinear loads of consumers, as well as the influence of the topology of the electric network.
K&C suspension parameters stability by production tolerances
Authors: Borisenko Vladislav , Kiselev Artem , Leoro Luis , Borovkov Aleksei , Boldyrev Yury
Published: December 2019

This paper considers a modern approach of K&C parameters stability analysis using the suspension MBS model of a short-wheelbase electric vehicle. According to the results of the work, even minor errors in suspension hardpoints positioning when overlaying can greatly affect the K&C parameters of car suspensions. Using MBS models, quasi-static K&C events have been simulated. In the same way the dependences of the suspension K&C parameters are numerically determined. Moreover, these calculations were made with different hardpoints positions for joints of wishbones fastening on a frame, and joint of a steering rod with a steering rack. The influence of suspension hardpoints displacement on the K&C parameters of the vehicle was estimated. As a result, recommendations are made for production positioning tolerances of suspension hardpoints in order to avoid deterioration of K&C parameters. Basically, the appearance of inaccuracies in the positioning of hardpoints leads to critical changes in anti-dive, anti-lift, kingpin inclination angle, bump camber and bump steer parameters.
Development of measures to ensure information security in structural division of the university
Authors: Boltyonkova Elena , Andreev Andrey , Doronin Alexander
Published: December 2019

In this paper we have determined the place of information security in the national security system of the Russian Federation and analyzed information processed in higher education institutions. The categorization of the processed information in the information system of the Higher School of Technosphere Safety is carried out. The estimation of the potential violator of information security is executed and an improved threat model is made, on the basis of which we have formulated practical proposals for the protection of information in the structural unit of the University.
Research of noise-proof feature of addressable fire indication system with sequential addressing
Authors: Balabanov Ivan , Shtonda Daria , Nikitina Maria
Published: December 2019

Currently, one of the ways to quickly detect fires in buildings is an automatic fire alarm system. The alarm loop is the most “vulnerable” part of the security and fire alarm system. This article is devoted to the study of the stability of the address fire alarm system with serial addressing under the influence of electromagnetic interference and other interfering factors. During the study, the system performance was evaluated when changing the parameters of the communication line and the stability of the transmission of the measured controlled parameter from the multicriteria detector having a heat and smoke sensor to the control panel of the DEMP DT №1. The influence of electrical impulse noise on the stability of the system was evaluated.
Methodology for assessing the environmental characteristics of various methods of generating electricity
Authors: Gryznova Ekaterina , Davydov Vadim , Batov Yuri , Dudkin Valentin , Puz’ko Danila , Myazin Nikita , Rud Vasiliy
Published: December 2019

The article considers the energy efficiency of energy production from various types of fuel. The analysis of the negative impact of the use of various types of fuel on the environment. The most significant indicators for assessing the environmental efficiency of the use of fuel for electricity production are established. A comparison is made with the performance indicators that are currently used. The advantages and disadvantages are established. The necessity of developing a more effective methodology for assessing environmental performance is substantiated. A new methodology for assessing the environmental efficiency of using various methods for the production of electricity is proposed. Research results are presented.
Elimination of the consequences of an emergency situation at a fire and explosion hazardous facility with the presence of flammable liquids
Authors: Klochikhin Ilya , Gomazov Fedor , Scherbakov Andrey , Chalovskaya Ekaterina , Uvarova Anastasia
Published: December 2019

The safety of technological processes and order of elimination of the emergency situations arising on fire and explosion hazardous objects with availability of flammable liquids and vapours, the reasons and the mechanism of appearance of an emergency situation is considered. The analysis of process of emergence of an emergency situation on potentially hazardous production facility in Russia and St. Petersburg is made. Mechanisms of development of an emergency on the object containing fire and explosion hazardous and easily flammable liquids at various scenarios of passing of an emergency situation are constructed: floods, ignitions and manifestations of secondary dangerous factors. Priority tasks for carrying out effective and safe mitigation of consequences of the arisen emergency situation are designated. The technology and models elimination of an emergency situation on the object containing fire and explosion hazardous and easily flammable liquids on the example of explosion with the subsequent burning of the gas mixture formed in a consequence of evaporation of oil products in reservoir park of Ruchi oil depot in the city of St. Petersburg is developed. Recommendations for the officials controlling actions for elimination of an emergency situation on this object are developed.
Modelling of forest decluttering technology along with estimation of deadwood amount
Authors: Karpachev Sergey , Makuev Valentin , Bykovskiy Maksim
Published: December 2019

A technology has been proposed for cleaning the forest from deadwood along with an evaluation of its total amount on the site (CFD). The basis of the deadwood quantitative evaluation is the linear intersection sampling (LIS). Within the CFD framework technology, the paper considers the technique of harvesting deadwood using a portable winch with a cable length from 40 to 120 m. A mathematical model has been developed of both the technological process and deadwood estimation. In the model, a number of sites were considered accounting for 50 to 150pcs of deadwood / ha. The results of simulation experiments have showed that the required number of sampling lines decreases in a power-law dependence with an increase in the amount of deadwood on the site and the length of the winch cable (sampling line). For the accuracy index P = 20%, the required number of sampling lines is within the range of 10-70 pcs / ha. Errors between the true values of the deadwood amount on the strip and its estimates did not exceed 7% in absolute value. At the same time, the deviation of the estimates depends neither on the amount of deadwood on the strip nor the length of the winch cable (sampling line). Errors in estimating the mean deadwood length for a sample made from the pieces that crossed sampling lines did not exceed 3%. The estimation procedure impact on the deadwood harvesting productivity proved to be negligible. The drop in performance does not exceed 1%. The impact of the amount of deadwood on the productivity on the site can be considered insignificant. With an increase in the length of the winch cable, a noticeable decrease in productivity is observed. Thus, with an increase in the length of the cable from 40 m to 120 m, productivity drops by 40%. This is due to the fact that the technology in question assumes piece skidding of deadwood. In this case, the time it takes to unwind the cable to a greater distance exceeds the time for the skid relocation. However, should the technology change, for example, in case of using a more powerful winch and skidding several trees at the same time, the situation may change.
Capacity payment allocation in hydrothermal power systems with high shares of renewable energies
Authors: Benavides Carlos , Álvarez Ricardo , Torres Rigoberto , Moreno Rodrigo , Matus Marcelo , Muñoz D. Francisco , González José M. , Jiménez-Estévez Guillermo , Palma-Behnke Rodrigo
Published: December 2019

The increasing use of variable generation technologies (VGTs) in power systems, such as wind and photovoltaic generation, has introduced new challenges in the definition of capacity remuneration mechanisms for promoting system reliability. In this context, in this article we propose a novel framework for determining the capacity value of VGTs to contribute to the generation system adequacy, as well as a corresponding method for allocating capacity payments in hydrothermal power systems. We show that the capacity value of VGTs increases with the presence of water reservoirs, since VGTs help relieving hydropower plants from using scarce water resources during off-peak hours thus making more resources available to supply the demand during peak hours.
Development of a concept of an energy-efficient house for an environmentally friendly settlement in the South Ural
Authors: Gandzha Sergey , Aminov Dilshod , Kosimov Bakhtiyor , Nimatov Rustam , Davlatov Azamdzhon , Mahmudov Azamjon
Published: December 2019

Creation of comfortable housing for the population meeting the modern requirements of ecology, aesthetics, economical energy consumption and healthy lifestyle is a strategic task of any state. The world’s leading countries have achieved significant results in this direction. In the context of economic sanctions, Russia will not be able to take advantage of the scientific achievements of foreign countries. In addition, our country has its own climatic features. Therefore, this strategic direction of development should be implemented independently. The project should go through several stages of development. At the first stage, all the necessary scientific research should be carried out. In the second stage, these scientific studies should find their engineering solutions. At the third stage, an industry for the production of such settlements should be established. This article attempts to formulate the basic requirements for the house, site and the most ecological settlement. The authors of the project consider this to be a very important initial stage of the project development.
Immunapherese bei akutem Multiple-Sklerose-Schub
Authors: Lehner Helmut
Published: December 2019

Leitliniengerechte Methylprednisolontherapien mit 1 g über 3–5 Tage führen leider nicht immer zu einer gewünschten Remission der Symptomatik bei MS-Patienten (MS: Multiple Sklerose). Hier bietet die Immunapherese für manche Patienten meist die einzige verbliebene leitliniengerechte Behandlungsmethode.
S2e-Leitlinie „Therapie der rheumatoiden Arthritis mit krankheitsmodifizierenden Medikamenten“ – was ist neu?
Authors: Fiehn Christoph
Published: December 2019

Jeder Patient mit aktiver rheumatoider Arthritis (RA) soll ein DMARD erhalten. Wie bisher ist dabei Methotrexat die Therapie der ersten Wahl. Die Therapie soll dabei zielgerichtet erfolgen (Prinzip des Treat to target). Remission, oder, wenn diese nicht zu erreichen ist, zumindest die niedrige Krankheitsaktivität sind die angestrebten Therapieziele. Remission ist definiert als ein Simplified Disease Activity Score (SDAI) von ≤ 3,3 oder als die Erfüllung der sogenannten Booleschen Kriterien. Eine erste Evaluation des Ansprechens ist nach 12 Wochen vorgesehen. Zu diesem Zeitpunkt sollte ein Ansprechen messbar sein, was als mindestens 50 %ige Verbesserung des Composite Score (z. B. des DAS28) definiert ist. Findet sich nach 3 Monaten kein Ansprechen oder ist nach 6 Monaten das Therapieziel nicht erreicht, soll die Therapie eskaliert werden. Abhängig von dem Vorhandensein von Risikofaktoren für einen schweren Verlauf soll entweder eine zweite DMARD-Strategie mit konventionell synthetischen DMARD (csDMARD) oder aber die Umstellung auf biologische oder targeted synthetic (b oder ts) DMARD erfolgen. Glukokortikoide werden initial gegeben, sollen aber nach 3–6 Monaten ausgeschlichen oder auf eine Dosis von max. 5 mg/d Prednisolon reduziert werden. Im weiteren Verlauf sind sowohl Wechsel innerhalb der b- und tsDMARD wie auch Deeskalation der Therapie möglich.
Homöopathie – Stand der Forschung
Authors: Behnke Jens
Published: December 2019

Outcome-Studien belegen, dass PatientenunterHomöopathie klinisch relevante Therapieeffekteerfahren, die denjenigen inderkonventionellen Behandlung ähneln, jedochmit weniger Nebenwirkungen. PlacebokontrollierteStudien (RCTs) und derenMetaanalysendeuten auf eine spezifische Wirksamkeitpotenzierter Arzneimittel. Es mangeltaber an hochwertigen Studien undunabhängigenReplikationen. In der präklinischenForschung zur Homöopathie existieren zuviele „positive“ Befunde, um sie ohne Weiteres durch die Placebohypothese zu erklären.Ein harter naturwissenschaftlicher Nachweissteht aber bislang aus.
Topical Application of 7,3′,4′-Trihydroxyisoflavone Alleviates Atopic Dermatitis-Like Symptoms in NC/Nga Mice
Authors: Park Sang Hun , Lee Chang Hyung , Lee Ji Yun , Yang Hee , Kim Jong Hun , Park Jung Han Yoon , Kim Jong-Eun , Lee Ki Won
Published: December 2019

Atopic dermatitis is a skin disease characterized by chronic inflammatory lesions, and new therapies are needed to address its rising prevalence. Soy isoflavone has been highlighted as a potential new cosmeceutical material that may have applications in atopic dermatitis care. We have developed a technique to attach an additional -OH group to the ortho position of -OH in the phenol ring using a special enzyme. By adding the -OH group to daidzein, 7,3′,4′-trihydroxyisoflavone can be generated for possible use as a cosmeceutical and functional food material. In this study, we sought to examine the anti-atopic effects of 7,3′,4′-trihydroxyisoflavone, an analog of daidzein. Topical application of 7,3′,4′-trihydroxyisoflavone reduced Dermatophagoides farina extract-induced atopic dermatitis symptoms in NC/Nga mice. Histological analysis demonstrated that 7,3′,4′-trihydroxyisoflavone suppressed D. farina extract-induced infiltration of eosinophils and mast cells into skin lesions. We also found that 7,3′,4′-trihydroxyisoflavone significantly reduces the D. farina extract-induced increases in serum IgE and macrophage-derived chemokine (CCL22) levels. We observed that 7,3′,4′-trihydroxyisoflavone suppresses atopic markers including macrophage-derived chemokine (CCL22) and thymus and activation-regulated chemokine (CCL17) in HaCaT cells. 7,3′,4′-Trihydroxyisoflavone also reduced TNF-α/IFN-γ-induced phosphorylation of ERK1/2 and JNK1/2. These results highlight several desirable properties of 7,3′,4′-trihydroxyisoflavone, which support its use as a cosmeceutical ingredient for the treatment of atopic dermatitis.
Efficient chemical vapour deposition and arc discharge system for production of carbon nano-tubes on a gram scale
Authors: Rajaura Rajveer Singh , Singhal Ishu , Sharma Kamal Nayan , Srivastava Subodh
Published: December 2019

Three indigenous systems—the underwater arc discharge setup, the inert environment arc discharge system, and the chemical vapor deposition (CVD) system—for the gram-scale production of carbon nanotubes were designed and fabricated. In this study, a detailed description of the development and fabrication of these systems is given. Carbon nanotubes were synthesized by using all the three systems, and comparative analyses of the morphology, composition, and purity were done. The synthesized materials were characterized using scanning electron microscopy, X-ray diffraction (XRD), and Raman spectroscopy. The scanning electron microscopy images show agglomerated tubed fiberlike structures in samples from the arc discharge setup, whereas samples from the CVD system do not show any tubelike structures decorated around the carbon nanotubes. Structural investigations done using powder XRD revealed the presence of the hexagonal crystallographic phase. Furthermore, the presence of the G and 2D bands reveals sp2 hybridization and confirms the presence of carbon nanotubes in samples. In conclusion, carbon nanotubes synthesized via the CVD system is of high quality and quantity. Moreover, the CVD is a cheap, easy to operate, and energy-saving synthesis method compared with the other two methods.
Algebraic backgrounds for noncommutative Kaluza-Klein theory. II. The almost-commutative case and the standard model
Authors: Besnard Fabien
Published: December 2019

We define almost-commutative algebraic backgrounds and give conditions on them allowing us to compute their configuration space in terms of those of the continuous and finite parts. We apply these results to a background with finite algebra C⊕H⊕M3(C) and find that the configuration space is larger than the one obtained from the fluctuations of the metric and contains in addition to the Standard Model (SM) gauge fields, the ZB-L′-boson, a complex scalar field σ, and flavor changing fields. The latter can be removed similarly to centralizing fields in the gravity model studied in the first part. The remaining fields belong to a U(1)B-L-extension of the SM.
Non-linear behavior of flexoelectricity
Authors: Wang Zhiguo , Song Ruobing , Shen Zhenjiang , Huang Wenbin , Li Chunchun , Ke Shanming , Shu Longlong
Published: December 2019

Coupling between polarization and the strain gradient, namely, flexoelectricity, is a universal phenomenon that widely exists in all solid dielectrics and polymers. At a low level of the applied strain gradient, this electromechanical coupling is strictly a linear effect. In this Letter, a strong nonlinearity between the polarization and the strain gradient was experimentally found in polyvinylidene fluoride when the strain gradient was higher than a material-dependent threshold value. Such nonlinear behavior was in good accordance with an ion chain theory and could be fitted by a nonlinear equation. The observed flexoelectric nonlinearity in this work will help in the understanding of the discrepancy between the previous findings about the bulk materials and their nanoscale counterparts.
Resonant microwaves probing the spatial afterglow of an RF plasma jet
Authors: Platier B. , Staps T. J. A. , van der Schans M. , IJzerman W. L. , Beckers J.
Published: December 2019

The electron density and effective electron collision frequency in the spatial afterglow of a pulsed radio frequency driven atmospheric-pressure plasma jet are obtained by using microwave cavity resonance spectroscopy in a temporal manner with an ∼1 μs resolution. During the “plasma on” phase, values of 1.7 ± 0.3×1018 m−3 for the electron density and 0.12 ± 0.01 THz for the electron collision frequency were found. These values and standard deviations represent the collective measurement set with repetition rates ranging from 125 to 8000 Hz. The spread in the plasma parameters during this phase within one repetition frequency is smaller than 3%. It is observed that remnant species, e.g., metastables, of previous discharges influence the decay of the plasma. The work reported is enabled by recent developments in the applied diagnostic with respect to the resolution in the plasmas' permittivity. Moreover, a multiplying probe is used for the electrical characterization of the plasma and the presence of the cavity did not influence the plasma impedance. This strongly suggests that the cavity did not affect the discharge.
Temperature-gradient effects on heterogeneous ice nucleation from supercooled water
Authors: Wang Liping , Kong Weiliang , Wang Fuxin , Liu Hong
Published: December 2019

Investigating the nucleation and freezing behavior of supercooled water under temperature gradients is of significance for theoretical research and practical application. This paper focuses on the freezing temperature of bulk supercooled water in a rectangular container for which the temperature at two sides can be controlled to present a temperature difference. The experimental results show that the nucleation temperature under temperature differences will be lower than that under isothermal conditions. In addition, an increase in the temperature difference is shown to linearly increase the supercooling needed for ice nucleation. The temperature gradient is capable of suppressing heterogeneous ice nucleation. Based on the classical nucleation theory, the free energy barrier for heterogeneous nucleation is attributed to the main factor to affect the nucleation rate. By comparing theoretical evaluations with experimental results, correction on the free energy barrier was conducted to predict the nucleation rate in the temperature gradient. Our experimental research and theoretical correction reveal the nucleation behavior of supercooled water under nonequilibrium conditions.
Dopant activation and photoresponses of boron-doped silicon by self-assembled molecular monolayers
Authors: Fu Jing , Chen Kaixiang , Chang Shannan , Zhi Kanru , Gao Xuejiao , Wei Hao , Dan Yaping
Published: December 2019

Self-assembled molecular monolayer doping is an emerging doping technique. In this work, we investigated the activation rate and photoresponses of boron doped silicon by self-assembled molecular monolayer doping. By using low temperature Hall effect measurements and by secondary ion mass spectroscopy, we find that the activation rate of boron in these samples is in the range of 91%–54%, depending on the doping concentration. Interestingly, the photoresponsivity of the boron doped samples is also significantly higher than that of the phosphorus doped samples even though the same doping technique is used. The intriguing photoresponses are closely related to the trapping of photogenerated minority carriers by the defects in the p-type silicon.
High-compact picosecond laser functionalizes surfaces with microscale precision
Authors: Liebendorfer Adam
Published: December 2019

Diffractive optics allows 500-watt pulses to rapidly functionalize surfaces in up to 16 parallel beamlets, each controlled by an acousto-optical modulator.
Action Plan for Australian Lizards and Snakes 2017
Authors: Chapple David , Tingley Reid , Mitchell Nicola , Macdonald Stewart , Keogh J Scott , Shea Glenn , Bowles Philip , Cox Neil , Woinarski John
Published: December 2019

Lizards and snakes (squamate reptiles) are the most diverse vertebrate group in Australia, with approximately 1000 described species, representing about 10% of the global squamate diversity. Squamates are a vital part of the Australian ecosystem, but their conservation has been hindered by a lack of knowledge of their diversity, distribution, biology and key threats.
The Action Plan for Australian Lizards and Snakes 2017 provides the first comprehensive assessment of the conservation status of Australian squamates in 25 years. Conservation assessments are provided for 986 species of Australian lizards and snakes (including sea snakes). Over the past 25 years there has been a substantial increase in the number of species and families recognised within Australia. There has also been an increase in the range and magnitude of threatening processes with the potential to impact squamates. This has resulted in an increase in the proportion of the Australian squamate fauna that is considered Threatened. Notably over this period, the first known extinction (post-European settlement) of an Australian reptile species occurred – an indication of the increasingly urgent need for better knowledge and management of this fauna. Six key recommendations are presented to improve the conservation management and plight of Australian squamates.
This Action Plan represents an essential resource for research scientists, conservation biologists, conservation managers, environmental consultants, policy makers from Commonwealth and State/Territory governments, and the herpetological community.
Current velocity, temperature and oil thickness as determinants of the refloating process of stranded oil in the Bohai Sea
Authors: Yu Yue , Qi Zhixin , Yu Xinping , Li Wenxin , Fu Sinan , Xiong Deqi
Published: December 2019

After oil spill accidents, weathered oil slicks can drift to coastal areas and interact with shoreline substrates. This process has been demonstrated to be the cause of the formation of stranded oil, which has attracted much attention. However, the refloating process of stranded oil when coastal hydrodynamic conditions change has been little investigated. This study evaluated the effects of current velocity, temperature and oil thickness on the refloating process of a simulated oil patty in a flow-through tank. The oil refloating efficiency (ORE) was used to quantitatively examine the degree of refloating. Non-linear fitting results indicated that the ORE increased gradually over time and then plateaued. Both observations and measurements indicated that higher current velocity brought about more oil refloat and enhanced the oil refloating rate. Furthermore, both the mass of refloating oil and the oil refloating rate showed a positive linear correlation with current velocity. The effects of temperature on the oil refloating process were determined by the effects of temperature on oil viscosity. In addition, the ORE at equilibrium increased linearly with increasing oil thickness. An empirical model was introduced and found to be closely consistent with the experimental data. This information is useful in predicting the fate and transport of stranded oil in the Bohai Sea.
The role of negation in the grammaticalization of ability verbs
Authors: Wilson Brianna , Hansen Cynthia
Published: December 2019

This paper investigates the role of negation in grammaticalization in Iquito, an endangered Zaparoan language of the Peruvian Amazon. Iquito has a verb,pajɨɨni, which has undergone two paths of grammaticalization only in negated clauses. First,pajɨɨnihas grammaticalized from “learn” to “be able to.” Subsequently, it is undergoing grammaticalization from an ability verb to a future auxiliary. Given that ability verbs are an uncommon source for future auxiliaries (Bybee et al. 1994), this study provides a detailed case study of this rare path. Our analysis of Iquito demonstrates that grammaticalization paths are not limited to affirmative contexts and may behave differently depending on the polarity of the utterance.
Why and how the nematode’s early embryogenesis can be precise and robust: a mechanical perspective
Authors: Tian Binghui , Guan Guoye , Tang Lei-Han , Tang Chao
Published: December 2019

The early embryogenesis in the nematode Caenorhabditis elegans is well-known for its stereotypic precision of cell arrangements and their lineage relationship. Much research has been focused on how biochemical processes achieve the highly reproducible cell lineage tree. However, the origin of the robustness in the cell arrangements is poorly understood. Here, we set out to provide a mechanistic explanation of how combining mechanical forces with the order and orientation of cell division ensures a robust arrangement of cells. We used a simplified mechanical model to simulate the arrangement of cells in the face of different disturbances. As a result, we revealed three fail-safe principles for cell self-organization in early nematode embryogenesis: ordering, simultaneity, and the division orientation of cell division events. Our work provides insight into the developmental strategy and contributes to the understanding of how robust or variable the cell arrangement can be in developing embryos.
Development of Physics Learning Media Based on Self-Efficacy Use Mobile Augmented Reality for Senior High School
Authors: Nasir Muhammad , Fakhruddin Z , Prastowo Rizo Budi
Published: December 2019

It was found that the value of self efficacy in physics learning in high school (SMA) is still low in one school. Self-efficacy was found at the level of 48%. And this is supported by OECD data (3) which also states that the performance of Indonesian science more than 55% of students score below level 2 out of 5 levels. The development of self-efficacy media in learning physics astronomy is an effort made to improve students’ self-efficacy. Media self-efficacy is designed using mobile augmented reality which is considered capable of giving students a better learning experience so as to be able to improve student learning abilities so that students’ self-efficacy also increases. To be able to improve self-efficacy better this media must be supported by teacher assistance as a motivator to students so that the effects given are even better.
The Leaching Process of Alumina from Red Mud for Synthesis of Mesoporous Alumina
Authors: Ramdhani E P , Permana D , Wulandari F , Prasetyoko D
Published: December 2019

Alumina was leached from red mud by hidrometalurgy method. Alumina from red mud was leached by desilication process, separation of iron oxide process, and formation of alumina salt process. Residu of each step was characterized by X-ray diffraction (XRD), X-ray flourence (XRF), scanning electron microscopy-energy dispersive x-ray analysis (EDX). From X-ray diffraction result. The composition of red mud from Bintan was determined by characterization process with X-ray diffraction (XRD) and X-ray flourence (XRF) that show red mud from Bintan contains hematite (Fe2O3), gibbsite (Al(OH)3), boehmite (γ-AlO(OH)), anatase (TiO2) dan quartz (SiO2). After desilication process, SiO2 on residue of red mud were collected 38.85 wt.%. From separation of iron oxide process, the residue of leaching process was Fe2O3 81.80 wt.%. The product from formation of alumina salt process was characterized by scanning electron microscopy-energy dispersive x-ray analysis (EDX) that showed the leaching process of alumina from red mud had element oxygen and aluminium in its salt amounted to 64.94 wt.% and 26.40 wt.%. The product could be the source of alumina to synthesis of mesoporous alumina.
Antibacterial Activity of Red Dragon Peel (Hylocereus polyrhizus) Pigment
Authors: Hendra Rudi , Masdeatresa Lidya , Abdulah Rizky , Haryani Yuli
Published: December 2019

Red dragon fruit (Hylocereus polyrhizus) is a species of plant that provides natural pigment which is betalain. Betalain is a one of the pigments that gives a natural colour to flowers and fruits. Moreover, of betalain in red dragon fruit peel, there are bioactive compound such as polyphenol and flavanoid with antioxidant and antibacteria activities. This research was objected to extract pigments and others secondary metabolites from red dragon fruit peel using ethanol, methanol, dicloromethane and ethyl acetate solvents, continued with determined potential antibacteria activity using Resazurin Microtitter Assay (REMA) method. The results of antibacterial activity showed inhibition percentage against test of positive Gram bacteriaStreptococcus aureusATCC 29213 with extract ofn-haxane, ethyl acetate and pigment sequentially were 67.5, 67.0, 85.1, 83.1 % andBacillus subitilisATCC 11774 were 73.4, 98.6, 97.1, 100 % and negative Gram bacteriaEscherichia coliATCC 35218 were 70.0, 73.1, 74.2, 94. 9 % andVibrio algynolyticuswere 72.6, 73.1, 74.2, 94.9 % at final concentration of 20 μg/mL
Critical Thinking Skills of Fifth Grade Elementary School Students in Bandung City on the Topic of Water Cycle in Natural Science Subjects
Authors: Syaodih E , Kurniawati L , Handayani H , Setiawan D , Suhendra I , Hermita N
Published: December 2019

Critical thinking skills are skills that a person needs to have. Therefore developing students’ critical thinking skills is one of the main goals in 21st century education. The purpose of this study is to describe the critical thinking skills of fifth grade elementary school students on natural science subjects on water cycle topics. The research method used in this research is a quantitative descriptive method. The participants of this study were 25 elementary school students in Bandung city. The data is collecting by tests, interviews and documentation. After the data is obtained, the test is processed and analyzed using quantitative methods. The results of interviews and documentation studies were analyzed using descriptive methods. The research results showed that the critical thinking skills of fifth grade students in the elementary school of Bandung city were in the very poor category. The average score of students’ critical thinking skills is 48.3 (very low). The interview results show that students’ critical thinking skills are low because students do not like the type of description questions and because they did not willing to write. Students, who are in the low and medium category, are having another reason, which is they do not like to learn science.
Evolutionary Study of Binary Star Beta Lyr
Authors: Putra Singgih Prana , Aprilia
Published: December 2019

We present the evolutionary track of Beta Lyrae (β Lyr), an interacting eclipsing binary star, with orbital rotation period of 12.94 days, with one component known as the B-emission (Be) star. The primary star is a B6-B8II of 3M⊙ and the secondary is a 13M⊙ B0.5V star. The secondary star is embedded in the accretion disc produced by the infalling matter from the primary star, and this disc is estimated as the source of the emission lines. The evolution of the β Lyr system is simulated by using MESA software with the MESAbinary programming code. We obtain that the age of the binary system is 2.7 × 107 years, mass and radius of the primary component are M1 = 3.54M⊙, R1 = 16.1R⊙, and mass and radius of the secondary component are M2 = 13.1M⊙, R2 = 6.85R⊙.
Energy Refurbishment of the General Physiology Institute at Sapienza University Campus
Authors: Pini Fabrizio , Romano Giada , Aureli Cristina
Published: December 2019

The energy requalification of the existing building heritage is one of the pillars European Union energy policy. A large part of the building heritage was built without taking into consideration the problem of energy consumption. With the aim of energy efficiency and energy savings in electrical uses, there are wide and diversified possibilities for improvement, including interventions on the building envelope and on the systems, with the introduction, where possible, of renewable energy sources. In this context, the redevelopment of historic buildings constitutes an important challenge, which involves both historical-artistic aspects and technological aspects relating to the improvement of energy efficiency and comfort. A critical analysis of every possibility is essential to preserve the balance between efficiency and architecture. The purpose of the study is the energy retrofitting of the Institute of General Physiology located within the “Sapienza” University campus. The proposed interventions include the renovation of the whole building envelope, investigated by thermographic surveys, and the installation of new heating and cooling systems. The results were analysed to identify the best intervention for a sustainable energy renovation of the historic building, taking into account the preservation of its architectural values and making it suitable for modern use.
Simulation Effect of Crack Depth and Crack Location on Cylindrical Pressure Vessel
Authors: Kusmartono Dodik , Nugroho Gesang
Published: December 2019

In the present study the problem of calculation of the stress intensity factors (SIF) of semi-elliptical cracks located in the shell and knuckle area of a pressure vessel is numerically solved by 3D Extended finite element method (XEFM) analysis. Crack also will be varied based on crack depth at constant elliptical ratio. The modeling details of the sub-structuring methodology, employed in the analysis, are discussed and the numerical approach is proven to be very efficient for the SIF calculation of pressure vessel semi-elliptical crack. Result of study show that crack with the same geometry, crack located in the shell has more tendency to propagate compare to crack located in the knuckle area. This phenomenon is due to stress at shell is dominated with tensile stress while in the knuckle area, stress is dominated with compressive stress.
Application Seasonal Autoregressive Integrated Moving Average to Forecast the Number of East Kalimantan Hotspots
Authors: Wahyuningsih S , Goejantoro R , Siringoringo M , Saputra A R , Aminah S
Published: December 2019

The objective of this research is to determine the best time series model for forecasting the number of hotspots in East Kalimantan. Seasonal time series model is applied to the data. The results of this research is the best model for the number of hotspots in East Kalimantan is SARIMA (0,1,1)(0,1,1)12.
Graphene Nanosheets (GNs) Addition on the Palm Oil Fuel Ash (POFA) Based Geopolymer with KOH Activator
Authors: Amri Amun , Hendri Yola Bertilsya , Zultiniar  , Malindo Eri , Rahman M Mahbubur
Published: December 2019

Graphene Nanosheets (GNs) have been successfully added to the palm oil fuel ash (POFA) based geopolymer with KOH activator to improve the geopolymer compressive strength. The graphene was synthesized using turbulence assisted shear exfoliation (TASE) method and identified using Raman spectroscopy. The influence of concentrations and weight percent of graphene against the compressive strength, porosity, and morphological properties were investigated. The crystallinity phases of geopolymer and graphene were also identified using XRD. Raman spectroscopy revealed that graphene produced by TASE method had ≥ 3 layers (graphene nanosheets, GNs). Furthermore, Raman maping constructed by the intensity D band showed the graphene had different atomic arrangements at the edge (armchair and zigzag). The compressive strength and the porosity tests showed that increasing the concentration and the weight percent of graphene increased the compressive strength and reduced the porosity. The highest compressive strength and the lowest porosity (10.8 MPa and 5.92%, respectively) were exhibited by the geopolymer synthesized using 0.7 wt% graphene with concentrations of 30 mg/ml. The SEM micrographs indicated that the graphene reduced the porosity of geopolymers with a pores fulfilling mechanism due to of very small of graphene nanosheets size (∼60 - ∼80 nm).
The Effects of Zn/Natural Zeolite Ratio and Adsorbent Calcination on H2s Adsorption in Biogas on the Processing of Palm Oil Mill Effluent (Pome)
Authors: Manullang Freddy , Ahmad Adrianto , Andrio David
Published: December 2019

Biogas is a renewable energy source derived from organic material that is anaerobically degraded by bacteria in an oxygen-free environment. The main components of biogas are methane (CH4) and carbon dioxide (CO2). In addition, there are other relatively small amounts of gas, namely nitrogen (N2), hydrogen sulfide (H2S) and hydrogen (H2). The quality of biogas that is non-optimal can be improved by separating or eliminating impurity gases, one of which is hydrogen sulfide (H2S). Hydrogen sulfide (H2S) is a poisonous and odorous gas that causes corrosion, so it needs to be reduced in biogas. Hydrogen sulfide (H2S) in biogas can be reduced by adsorption methods using modified natural zeolites. The purpose of this study is to determine the effect of the natural Zn/zeolite impregnation ratio and the effect of the adsorbent calcination temperature on biogas purification and determine the concentration of hydrogen sulfide (H2S) from biogas purification. The adsorbent is synthesized with variation: natural Zn/zeolite ratio of 10%, 20%, 30% w / w and calcination temperature of 200°C, 300°C, 400°C. Adsorbents are characterized using X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The result of this research show that the optimum adsorption capacity of hydrogen sulfide (H2S) in biogas is obtained at a variable ratio of Zn/zeolite natural 20% and calcination temperature of 300°C is 6.36 mg S g adsorbent and H2S can be purified or adsorbed up to 99%.