bluuebunny/crossref_metadata_2025 huggingface dataset:
Motivations and challenges on the inclusion of environmental topics in Brazilian physics teacher education courses
Authors: Leite Danielle Aparecida Reis , Silva Luciano Fernandes
Published: February 2021

In Brazil, environmental topics in teacher education programmes have largely been addressed and explored by the field of research in Environmental Education and subsidized by legislative and normative instruments. Nevertheless, the difficulties in articulating environmental topics within some areas of knowledge compromise their integration in certain subject-specific courses, as is the case for initial physics teacher education courses. In this light, this article seeks to identify the main challenges and motivations to incorporating environmental topics in physics teacher education courses, with the aim of identifying strategies that may contribute to overcoming these difficulties. Interviews were carried out with 15 physics teacher education courses coordinators at state-funded higher education institutions in the state of São Paulo, Brazil. Drawing upon Content Analysis procedures, analysis was conducted on the interview transcripts as well as pedagogical plan courses. The main findings highlight that the presence of environmental topics in these programmes reflects legislative and normative requirements. In addition, other factors motivated the inclusion of environmental topics in these courses, thus indicating recognition of its importance to initial physics teacher education. This study also shows that the small number of university lecturers and professors involved in environmental education working within these programmes is the main challenge to including environmental topics in initial physics teacher education curriculum.
Secondary school students’ conceptions about the viscous behaviour of liquids
Authors: Faltin Lukas , Feser Markus Sebastian
Published: February 2021

Since the viscous behaviour of liquids is evident in many everyday situations, it is plausible to assume that students have (pre-)conceptions about the physics behind these phenomena. As yet, no reliable studies exist on this topic. Therefore, the present study aims to address this research gap by exploring secondary school students’ conceptions about the viscous behaviour of liquids. For this purpose, we conducted structured interviews with 12 ninth grade students, in which the students were asked to describe and explain various viscosity phenomena of everyday life, presented to them as video clips. Our analysis of the interviews revealed that many of the students have the conception that density is associated with viscous behaviour. In addition, some students explain viscous behaviour with reference to the ingredients of a liquid or by its stickiness or compression. Further, both macroscopic- and sub-microscopic-level explanations for the viscous behaviour of liquids emerged in the interviews.
Multiple electrically tunable parametric resonances in a capacitively coupled electromechanical resonator for broadband energy harvesting
Authors: Surappa Sushruta , Erdogan Tuna , Degertekin F Levent
Published: February 2021

Parametric excitation (PE) has widely been employed as a method of mechanical pre-amplification in nonlinear vibration energy harvesting systems. However, despite their advantages, most current PE systems are limited to degenerate parametric operation within a narrow frequency band around the primary instability tongue. In this paper, we simulate and experimentally demonstrate a parametrically driven capacitive electromechanical resonator having multiple electrical degrees of freedom. Multiple modes allow for several frequency bands in which the electrical resonator is driven into nondegenerate (combination) parametric resonance (PR) in addition to degenerate resonance, thereby enabling operation over a broader range of frequencies while maintaining the same mechanical footprint. These frequency bands and PR thresholds are tunable by simply changing the electrical circuit parameters and PR can be achieved in the presence of high mechanical damping making the method more adaptable than purely mechanical approaches. Experimental results are extended by simulations indicating that proper selection of operating parameters can enable the merging of instability tongues to produce a broadband region of PR for elastic wave energy harvesting thereby obtaining superior performance when compared to an equivalent single degree of freedom PE energy harvester.
Finite-time quantum Stirling heat engine
Authors: Hamedani Raja S , Maniscalco S , Paraoanu G S , Pekola J P , Lo Gullo N
Published: February 2021

We study the thermodynamic performance of a finite-time non-regenerative quantum Stirling-like cycle used as a heat engine. We consider specifically the case in which the working substance (WS) is a two-level system (TLS). The Stirling cycle is made of two isochoric transformations separated by a compression and an expansion stroke during which the WS is in contact with a thermal reservoir. To describe these two strokes we derive a non-Markovian master equation which allows to study the real-time dynamics of a driven open quantum system with arbitrary fast driving. Following the real-time dynamics of the WS using this master equation, the endpoints of the isotherms can deviate from the equilibrium thermal states. The role of this deviation in the performance of the heat engine is addressed. We found that the finite-time dynamics and thermodynamics of the cycle depend non-trivially on the different time scales at play. In particular, driving the WS at a time scale comparable to the resonance time of the bath enhances the performance of the cycle and allows for an efficiency higher than the efficiency of the quasistatic cycle, but still below the Carnot bound. However, by adding thermalization of the WS with the baths at the end of compression/expansion processes one recovers the conventional scenario in which efficiency decreases by speeding up the processes. In addition, the performance of the cycle is dependent on the compression/expansion speeds asymmetrically, which suggests new freedom in optimizing quantum heat engines. The maximum output power and the maximum efficiency are obtained almost simultaneously when the real-time endpoints of the compression/expansion processes are considered instead of the equilibrium thermal endpoint states. However, the net extractable work always declines by speeding up the drive.
A path integral approach to electronic friction of a nanometer-sized tip scanning a metal surface
Authors: Wang Yang , Jia Yu
Published: February 2021

In this work, we study the dissipation mechanism and frictional force of a nanometer-sized tip scanning a metal surface via a path integral approach. The metal, with internal degrees of freedom (c, c
†) and a tip with an internal degree of freedom (d, d
†) couple with one another by means of an exchanged potential, V. Having integrated out all internal degrees of freedom, we obtain the in-out amplitude. Moreover, we calculate the imaginary part of the in-out amplitude and the frictional force. We find the imaginary part of the in-out amplitude to be positive, and correlated to the sliding velocity in most cases. The frictional force is proportional to the sliding velocity for the case where v < 0.01. However, for cases where v > 0.01, the frictional force demonstrates nonlinear dependence on sliding velocity.
Infinitely many nonlocal symmetries and nonlocal conservation laws of the integrable modified KdV-sine-Gordon equation
Authors: Liang Zu-feng , Tang Xiao-yan , Ding Wei
Published: February 2021

Nonlocal symmetries related to the Bäcklund transformation (BT) for the modified KdV-sine-Gordon (mKdV-SG) equation are obtained by requiring the mKdV-SG equation and its BT form invariant under the infinitesimal transformations. Then through the parameter expansion procedure, an infinite number of new nonlocal symmetries and new nonlocal conservation laws related to the nonlocal symmetries are derived. Finally, several new finite and infinite dimensional nonlinear systems are presented by applying the nonlocal symmetries as symmetry constraint conditions on the BT.
High-efficiency reflection phase tunable metasurface at near-infrared frequencies*
Authors: Li Ce , Zhu Wei , Du Shuo , Li Junjie , Gu Changzhi
Published: February 2021

The realization of active modulation of reflection phase based on metasurfaces is of great significance for flexible control of electromagnetic wavefront, which makes metasurfaces have practical application values in polarization conversion, beam steering, metalens, etc. In this paper, a reflection phase tunable gap-surface plasmon (GSP) metasurface based on phase change materials Ge2Sb2Te5 (GST) is designed and experimentally demonstrated. By virtue of the characteristics of large permittivities difference before and after GST phase transition and the existence of stable intermediate states, the continuous modulation of near-infrared reflection phase larger than 200° has been realized. At the same time, through the reasonable design of the structure sizes, the reflection has been maintained at about 0.4 and basically does not change with the GST phase transition, which improved the working efficiency of the metasurface significantly. In addition, the coupled-mode theory (CMT) is introduced to make a full analysis of the modulation mechanism of the reflection phase, which proves that the phase transition of GST can induce the transition of metasurface working state from overcoupling mode to critical coupling mode. The improvement of the metasurface working efficiency has practical values for wavefront modulation.
Optical spectroscopy study of damage evolution in 6H-SiC by

H2+

implantation*
Authors: Wang Yong , Liao Qing , Liu Ming , Zheng Peng-Fei , Gao Xinyu , Jia Zheng , Xu Shuai , Li Bing-Sheng
Published: February 2021

Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques. One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization. In this work, confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV

H
2
+

implantation and thermal treatment in the microstructure of 6H-SiC single crystal. The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks. The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence. The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700 °C to 1100 °C. The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.
On the uncertainties in the realization of the kelvin based on thermodynamic temperatures of high-temperature fixed-point cells
Authors: Todd A D W , Anhalt K , Bloembergen P , Khlevnoy B B , Lowe D H , Machin G , Sadli M , Sasajima N , Saunders P
Published: February 2021

In July 2016 the Consultative Committee for Thermometry’s Non-Contact Thermometry Working Group formed a task group to compile a complete list of uncertainties for high-temperature fixed points, categorize them as well specified or not, and recommend areas of future research. We describe herein two paths to realizing T by indirect primary radiometry using high-temperature fixed-point blackbody cells: one in which published values for the metal–carbon eutectic material transition temperatures are used and the other where a set of cells has their transition temperatures determined directly. The uncertainty components that need to be considered for each path are given together with typically achievable values and how well those values are known. This work concentrates on Co–C, Pt–C and Re–C.
Research on Influencing Factors of Power Grid Security Risk Based on “Cognitive-Constraint” Model
Authors: Yu Lei , Lv Jin , Peng Qiwei , Zhao Linying , Li Gang
Published: February 2021

With the improvement of the intelligent level of the power grid, the operation safety of the power system has received extensive attention. The current accident analysis mostly relies on the experience of personnel, which is prone to omissions. Firstly, this article analyzes the safety risk factors of power grid accidents from four aspects: man factors, equipment factors, management factors, and environmental factors based on the accident causes theory. Secondly, the fault tree model is used to explore the mechanism of each failure factor and quantify the structural importance of each event. Finally, summarize the rules of accidents and make reasonable suggestions for scientifically and reasonably avoiding similar accidents and building a safe power grid.
Research on Modeling and Simulation of Smart Substation Cyber-Physical System Considering Coupling Analysis
Authors: Yang Huifeng , Chen Liandong , Cheng Kai , Li Gang , Wang Xinying
Published: February 2021

With the rapid development of Internet of Things and communication technologies, substations are becoming more intelligent, which brings opportunities for cyber attacks, threatens the safety of substations, and the high coupling of equipment in substations increases the threat. This paper analyzes and studies the information-physical characteristics and equipment coupling problems of smart substations, constructs a smart substation CPS model based on the balance equation of state quantity, and designs a line fault simulation example to verify the stability of the model.
Analysis on the Layout and Capacity Adaptability of China’s Coastal Iron Ore Unloading Terminals
Authors: Yao Haiyuan , Wang Dachuan , Li Yijun , Su Mengchao , Tang Guo-lei
Published: February 2021

As the most important raw material for the iron and steel industry, demand for iron ore is rapidly recovering with the steady recovery of domestic machinery, manufacturing and other iron and steel-related industries. Recently, the number of ore ships waiting to berth has increased significantly at the major iron ore unloading ports along the coast of China. Factors, such as weather influences and concentrated arrivals, make the problem of port ore ships under pressure reappear. This article describes the overall situation of China’s iron and steel market and coastal iron ore transportation and analyzes the characteristics of iron ore import transportation in various regions. The construction layout, stockpiling situation conditions and the capacity adaptability of China’s iron ore terminals are systematically studied. And it proposes that the specialized ore unloading terminals generally need to meet the demand of foreign trade imports. However, the capacity of the Bohai Rim, the Yangtze River Delta and the regions are-as along the coast is still tight, and the local port pressure is still prominent. In the future, further research and the optimization of China’s iron ore unloading terminal system should be done. Through AIS dynamic data monitoring, port and shipping big data mining and analysis, and the other new technical means, the adaptability of iron ore unloading capacity at terminal is refined research, the peak arrival of ships and other situations are properly handled, and China’s iron ore foreign trade Import transportation is protected stablly and safely.
Study on Scheme Optimization of bridge reinforcement increasing ratio
Authors: Shuai Song , Xili Qi , Shiyong Cao , Yi Xu , Huiying Ou , Hongbo Tao , Xiaoxu Huang
Published: February 2021

The bridge reinforcement methods, each method has its advantages and disadvantages. The load-bearing capacity of bridge members is controlled by the ultimate strain of concrete in the compression zone or the ultimate strain of reinforcement in the tension zone, so the selection of the bridge reinforcement method is affected by the section reinforcement ratio. When the reinforcement ratio of the section is between the minimum reinforcement ratio and the critical reinforcement ratio, we should choose the beam bottom reinforcement plan; when the section reinforcement ratio is between the critical reinforcement ratio and the maximum reinforcement ratio, it should be adopted Reinforcement method of bridge deck reinforcement layer.
Experimental evaluation of polymer performance for tertiary oil recovery in oil field
Authors: Liu Xiang
Published: February 2021

Polymer flooding is an important technology for enhancing the recovery of underground crude oil, and it is currently the most widely used technology for enhancing recovery in China. The main principle of polymer flooding is to increase the viscosity of injected water through a water-soluble polymer, thereby improving the mobility ratio, expanding the swept volume, and increasing the oil recovery rate and crude oil recovery factor. The viscosity-increasing performance of the polymer solution is the most important parameter of its oil displacement characteristics. The main factors that affect the viscosity of the polymer are the molecular structure, molecular weight, concentration, the salinity of formation water or injected water, temperature, and formation shear. Therefore, the viscosity-increasing performance, salt resistance, and shear resistance of the polymer are evaluated. Through indoor experiments under target reservoir conditions, the viscosity-concentration curves of four polymers A, B, C, and D are measured, and the viscosity data before and after shearing of the polymer as well as the viscosity of the polymer at different salinities are obtained. The results show that, considering the viscosity-increasing performance, shear resistance, salt resistance and quality control of the polymer, under the experimental conditions, the recommended sequence of the 4 polymers is: A, C, D, and B.
Application of composite foundation in marine environment
Authors: Xu Zhi Xiong
Published: February 2021

Under the marine environment, most of the underground projects will be eroded by the corrosive materials in varying degrees, which will lead to the deterioration of engineering materials, The reduction of structural strength, and affect the normal use and service life of the project; the rich sea water in the marine environment is often the premise of the smooth implementation of the underground projects, And the chaotic scouring of the intertidal sea water will affect the underground structure It has great influence on the strength of concrete. Generally, the measures taken for underground structure concrete include: improving concrete grade according to environmental category, adding admixtures, reducing water cement ratio, increasing compactness, etc. to improve concrete performance, anti-seepage, anti freezing, anti carbonization, anti-corrosion performance, increasing concrete protective layer thickness, brushing anti-corrosion materials, etc. to extend concrete durability; the measures taken for reinforcement include: coating epoxy resin, mixing anti rust agent, etc They can protect the concrete of underground structure to a certain extent, and the relevant specifications have corresponding provisions on it, but only qualitative provisions, the real effectiveness and validity period are unknown, the durability of the structure leaves long-term hidden danger, and also leads to the increase of construction cost. In marine environment, the foundation treatment under complex geological conditions can provide reliable working face for the construction of underground structure, eliminate the adverse impact of marine environment on the concrete of underground structure, and provide guarantee for improving the durability of concrete.
High resolution analysis based on deconvolution and matching pursuit
Authors: Sun Huajun , Qiong Li
Published: February 2021

The complexity of seismic exploration targets makes the exploration process more difficult and requires higher resolution of seismic data. Singular Methodology (inverse Q filtering, spectrum shaping, etc.) is limited in improving the resolution of seismic data and cannot meet the requirements of data interpretation. In this regard, combining time-varying frequency division deconvolution and matching pursuit (MP) methods, first perform time varying frequency division deconvolution processing on the original signal, and then use matching pursuit to remove the strong reflection seismic event and reconstruct the signal. Which can reflect the characteristics of reservoirs. By testing analog signals, deconvolution and matching pursuit methods improve the signal resolution. In the actual seismic data analysis, the comprehensive use of several methods can better identify the distribution characteristics of the effective tight carbonate reservoirs, and correspond well with the actual geological structure and drilling data. Which also provides a reference basis for further capacity analysis.
Oxidation-reduction state of lithospheric mantle in northern Xingmeng orogenic belt
Authors: Li Huaibin , Jinlai Feng
Published: February 2021

Xingmeng orogenic belt is located in the eastern part of East Asian orogenic belt, which is a typical area of superimposition and reconstruction of multiple tectonic systems. Spinel peridotite captives have been found in Nuo Min and Kolo areas in the north of Xingmeng orogenic belt. The olivine Mg# of lherzolite is 0.895 ∼ 0.911, which is slightly smaller than that of lherzolite (0.912 ∼ 0.928), and the high Mg# of lherzolite also indicates that the upper mantle in the study area is refractory. The lherzolite and lherzolite in the study area show high fO2 values, FMQ+1.947 ∼ 3.145, which is in sharp contrast with the relatively reduced ancient lithospheric mantle facies in general. The fundamental reason may be that the Paleozoic ancient Asian Ocean and the Mesozoic ancient Pacific Ocean successively subducted under the Xingmeng orogenic belt, resulting in the sharp rise of fO2 in the lithospheric mantle at that time.
Numerical simulation of the relationship between resistivity and microscopic pore structure of sandstone
Authors: Li Yuteng , Zhao Jiajia , Fao Tao , Liu Lei , Fang Zhe , Tian Xiaochao , Xiongwei Qu
Published: February 2021

The microscopic pore structure of the sandstone rock layer determines the water richness and permeability of the rock layer. Mastering the relationship between the resistivity of the sandstone rock layer and the microscopic pore structure is an important way to evaluate the water richness of the water-bearing rock layer from qualitative analysis to quantitative calculation. Using the finite element method to study the basic single and double modal structures in the sandstone layer of constant current field, the matrix resistivity, pore throat water resistivity, pore shape and difference in single sand model, pore throat model and capillary model are studied. The relationship between the direction of the current and the resistivity of the rock layer. The results show that the resistivity of the sandstone rock layer changes with the change of the matrix resistivity and has a linear relationship. When the contrast ratio between the sand and the matrix resistivity is between 10−1and 10, the resistivity of the rock layer changes linearly with the resistivity of the sand; when the contrast ratio is greater than 10, the influence of the resistivity of the matrix is smaller. And when the contrast is greater than 103, the resistivity of the rock layer tends to be constant; when the contrast is less than 10−2, the smaller the resistivity of the sand grains, the smaller the effect on the resistivity of the rock layer, and when the contrast is less than 10−3, the resistivity of the rock layer tends to constant. Since the water in the sandstone rock layer is the main conductive medium, when the water resistivity is fixed, the smaller the water saturation or the smaller the porosity, the smaller the pores through which water can flow and the greater the resistivity of the sandstone formation. When the microstructures of the horizontal and vertical rock layers are different, different transmitting and receiving electrode layouts have a greater impact on the resistivity of the rock layer, and the different microstructures lead to electrical anisotropy of the rock layer. The research results of this paper lay the foundation for the analysis of the relationship between the more complex sandstone rock model resistivity and micro-pore structure, and the quantitative calculation of the water richness of the sandstone rock layer.
Research on Faults Slip Rate in Weihe Basin based on GPS Data
Authors: Zhang Yongqi , Zhang Yuxiang , Cao Jianping , Ding Xiaoguang , Han Meitao
Published: February 2021

Based on the GPS data from 2001 to 2011 in Shaanxi Province, a three-dimensional geometric model of faults in Weihe Basin is constructed. Based on the deep fault dislocation model, the present slip rate of main faults in Weihe basin is studied. The results show that: (1) The place with large GPS fitting residual is located at the junction of two faults. (2) The slip rate inversion of most faults is consistent with the geological results, but the slip rate of some faults is quite different from the geological results, and even the movement mode changes. (3) In general, the activity of faults in Weihe Basin is relatively weak. Relatively speaking, the current tensile slip rates of Weihe fault, Chang’an-Lintong fault and eastern segment of northern Qinling fault are relatively high, which are (1.20 ± 0.87∼1.69 ± 1.24) mm/a, 2.54 ± 0.94 mm/a, 0.63 ± 1.00 mm/a, respectively.
Numerical Simulation on Failure Rules of Overburden Strata in Shallow Coal Seam
Authors: Senlin Huang
Published: February 2021

The mining, under the condition of the shallow coal seam, the thick loose beds and the thin base rock in Shendong mining area in Shaanxi province of China, makes the surface subsidence take on the situation of the discontinuous falling crack failure. A great deal of analysis and research indicates that the crack damage is controlled by the key strata in the overburden strata. Therefore, the key for solving the control of mining damage under this condition is to research the rules of the key stratum failure in the shallow seam. Taking 1203 longwall face in Daliuta mine of Shendong mining area as the example, the paper studies the relationship between the stability condition of the key stratum structure and the mining damage, supplying the theoretic evidence for the environmental protection and the confirmation of the reasonable and economical controlled mining methods in Shendong mining area.
Construction of Deposit Model-oriented Knowledge Graph
Authors: Qun Yan , Linfu Xue , Zeyu Liu , Xin Gao , Rui Wang , Junhao Dai
Published: February 2021

It has become a hot research direction under the background of artificial intelligence to effectively organize geological big data and to mine corresponding potential value. The knowledge graph, as a new form of knowledge representation, can effectively organize and represent data. This paper presents the deposit model ontology according to the triune framework of “ ore-forming geological body, ore-forming structure and structural plane, and mineralization mark” by centering on the deposit model, sets up the knowledge graph with the “branch intersection, top-down action and step-by-step layering” method, expresses and mines big data for geological text in the form of knowledge graph, and establishes a special knowledge graph for deposit model with semantic processing capacity and open interconnection capacity, providing a routine to match geological data from new perspective and showing the integrity and relevance of genesis features of deposits on deeper level. The results show this method can effectively realize semantic correlation and constraints between deposit model ontology, as well as retrieval and reasoning of correlation objects, and prove the usefulness of the research workflow in this paper.
Seismic Velocity Modeling in the Northwest Pearl River Mouth Basin, South China Sea
Authors: Lu Wenchao , Li Gang , Zhao Bin , Zhang Baojin , Gu Yuan , Li Yan
Published: February 2021

Accurate seismic velocity can determine the depth, dip angle and location of the stratum, and study the properties of rocks and pore fluid, such as rock density, reservoir location, gas hydrate anomaly and deep tectonic characteristics. The South China Sea (SCS) has special tectonic location and complex evolution history, which has always been the focus of geologists and geophysicists. At the same time, the SCS is rich in oil/gas resources, and is one of the four major marine oil-gas accumulation zones in the world. In this paper, three-dimensional velocity modeling was carried out in northwest Pearl River Mouth Basin of the SCS based on the three-dimensional geological framework model. Minimum Curvature Interpolation was used in the three-dimensional velocity modeling. Results showed that the three-dimensional velocity model can visually display sedimentary boundary and basin basement. The geological framework model makes the lateral velocity change of strata more in line with the actual geological structure. Considering the key role of the underground layer velocity in the exploration of oil, gas, hydrate and lower-crustal structure, it will be of great scientific and resources significance to carry out the three-dimensional velocity modeling research in the SCS.
Seismic stratigraphy analysis of main controlling factors of Lower Wuerhe Formation reservoir in Manan area
Authors: Jiang Qingping , Zhu Zhengping , Chang Tianquan , Li Sheng , Xiong Qian , Zhou Yang , Liu Kai
Published: February 2021

Fan delta sedimentary reservoirs developed in the Lower Wuerhe Formation of the Manan Slope in the Mahu Sag of the Jungger Basin have good prospects for oil and gas exploration and development. In order to clarify the high-quality reservoir system and the distribution range of the reservoir plane, a seismic stratigraphic interpretation of the Lower Wuerhe Formation is carried out in combination with geology, logging and 3D seismic data. The Lower Wuerhe Formation is divided into three stratigraphic series, a total of 8 four-level sequences, and 8 water body lifting cycles. Through seismic wave group and sedimentary evolution analysis, combined with pseudo-acoustic impedance amplitude and production test analysis, the high-quality oil-bearing reservoirs of the Lower Wuerhe Formation are mainly the third member of the Lower Wuerhe Formation. Oil-bearing reservoirs are mainly controlled by sedimentary facies belts caused by the ups and downs of water bodies. The well-developed oil-bearing reservoirs are developed in the fan delta plain-fan delta front-shore shallow lake sedimentary system.
Application of Gravity-flowed Convey Technology by Pipeline at Great Times Line for High Concentration Backfill Slurry
Authors: Sun Kaihua
Published: February 2021

In order to realize the gravity-flowed convey of high concentration backfill slurry of aeolian sand at 15 times line, the industrial test on convey by high concentration slurry backfill pipeline is carried out based on the calculation and analysis of backfill pipeline with respect to the design of the backfill pipeline and the critical velocity of slurry in Yuyang Coal Mine. The calculation and test results show that the high concentration aeolian sand backfill slurry has good fluidity, which drops markedly when the slurry concentration exceeds 72%. In order to achieve gravity-flowed convey of backfill slurry, it must be subject to an upper limit of concentration of 75%; The critical velocity of backfill slurry convey in Yuyang Coal Mine is 1.19m/s, with an operating velocity of 4.19m/s, which is 3.5 times of the critical velocity. With a maximum conveying capacity of backfill pipeline of 396m3/h, and high reliability in the pipeline convey of slurry, the great times line gravity-flowed convey of high concentration backfill slurry with aeolian sand as aggregate is achieved.
Composite of amorphous silica encapsulated urea as a slow-release fertilizer
Authors: Idris M , Sutarno  , Rusdiarso B
Published: February 2021

Composite of amorphous silica encapsulated urea as a slow-release fertilizer has been performed. Amorphous silica was obtained from dealumination of natural clay by the reflux method using HCl 6M. Encapsulation composite was prepared with amorphous silica mass variations of 0.50; 0.75; 1,00; 1.50; and 2.00 g. The preparation of encapsulation composite aimed to study the effect of amorphous silica mass on compressive strength and water absorption of composite. The XRD data showed that the dealumination process was successfully prepared by the formation of an amorphous diffraction pattern. The dealumination process was also supported by EDX data that indicated a decrease in the percentage of Al atomic weight from 11.29 to 0.36%. The optimum compressive strength and water absorption results were obtained at amorphous silica mass of 0.75 g with values of 5.40 MPa and 42.60%, respectively. The kinetics model followed the pseudo-second order for urea as a control and Korsmeyer-Peppas for composite of amorphous silica encapsulated urea with rate values of 0.847 mg−1 hour−n and 0.012 mg−1 hour−1, respectively.
Fabrication of magnetic activated carbon from spent coffee ground by hydrothermal synthesis for methylene blue removal
Authors: Rizkiana M F , Hidayatullah  , Rosalina A , Fachri B A , Harada H
Published: February 2021

Spent coffee ground-based magnetic activated carbon (MSC) was prepared using hydrothermal synthesis and utilized for the adsorption of methylene blue (MB). The MSC was made using the following conditions: the molar ratio of ferrous/ferric ions was 1:1.5, the hydrothermal treatment at 126°C for 2 h. The prepared MSC was investigated for surface morphology and chemical structure using FTIR and SEM. Batch adsorption studies were performed at 308 K; 318 K and MB concentration of 50-400 mg L−1 to evaluate the adsorption behaviour. The results showed as follows: there were C=O, C=C, C-O, Fe-O groups on the MSC surface and magnetite existed in the pores and surfaces of the MSC. Sorption behaviour at different temperatures were evaluated using the Langmuir, Freundlich, Temkin models, confirming Freundlich model was fitted on MSC. First and second order kinetic models were tested and the data fitted the first order behaviour. The adsorption process was a spontaneous, endothermic, and more reactive upon raising the temperature. After adsorption, MSC could be separated by applying magnetic field. Magnetic removal would allow convenient tool for adsorbent separation from contaminated water.
Synthesis and characterization of graphene-like material derived from sugarcane bagasse
Authors: Ariyanti Dessy , Lesdantina Dina , Budiyono  , Satriadi Hantoro
Published: February 2021

The superior ability of graphene has attracted much interest in both its development and application in various field. Graphene has been developed as material for a precursor for fabricating transparent conductive films, absorbents for environmental application, filler or additive in bioplastics, and many other applications. Graphene can be generated from carbon-based materials such as wood charcoal, sawdust, coconut shells, bagasse, rice husk, old tires, polymer-based waste, and cellulose. In this research, graphene is synthesized via Hummers route using carbon of sugarcane bagasse as raw materials. Parameter such as various addition of KMnO4 (5,10,15 gr) is observed. The characterization of the graphene such as X-Ray Diffraction (XRD), Fourier transform infra-red (FTIR) and scanning electron microscope (SEM) were used to investigate the different implication of the parameter applied during the production process. The results show that the graphene-like materials exhibit similar characteristics as published in previous works in term of crystalline structures, morphology, and its chemical bonding characteristics which can be used for diverse application as demonstrates by graphene derived from graphite exfoliation followed by reduction.
Prediction of Kappa number and carbohydrate degradation in oxygen delignification of Abaca fiber
Authors: Bazliah Dinda , Wulansari Safitri , Darmawan Aria , Idzati Eka Maulana , Ni’mah Hikmatun , Roesyadi Achmad , Kurniawansyah Firman
Published: February 2021

Abaca banana fiber (Musa textilis) is a source of non-wood fiber that can be used as material in the manufacture of pulp. Oxygen delignification is a process to reduce lignin content in pulp with Kappa numbers as parameters. In addition, carbohydrate degradation also occurs which is indicated by the value of viscosity. The purpose of this study is to predict the decrease in Kappa number, to predict carbohydrate degradation, and to determine the best operating condition based on prediction data obtained from the kinetic reaction model. Comparison between experimental data and prediction data was also analyzed. The prediction of Kappa number was started by developing kinetic model of oxygen delignification from experimental data, in which the rate of Kappa number reduction is dependent to temperature, hydroxy ion concentration, and oxygen pressure with specific reaction order of each species. Similar steps were done for predicting carbohydrate degradation. Prediction of Kappa number and carbohydrate degradation was done at various operating conditions, which are: oxygen pressures (2–5 bar), temperatures (70–100 oC), sodium hydroxide concentrations (NaOH) (1–5%), and heating times (0–120 min). The prediction results showed that the best operating conditions were at pressure of 2 bar, temperature of 85°C, 1% of NaOH for 56.6 min with a viscosity of 878.52 ml/g. This study also performed that the experimental data were fitted well with the prediction data.
Mass Transfer and Reaction in Hydrolysis of Coconut Husk Using Immobilized Enzyme on Chitosan Magnetic Nanoparticle
Authors: Putri N F , Dwinanda M R G , Widjaja A , Hamzah A , Sangian H F
Published: February 2021

A more sustainable energy source is needed to fulfill the increasing demand for energy. In Indonesia, biomass waste utilization as biofuel source shows high potential. Coconut husk is a biomass comprised of cellulose and hemicellulose that can converted to reducing sugar through enzymatic hydrolysis and can be further converted into biofuel. However, enzymatic hydrolysis is expensive, as enzyme is soluble and cannot be separated after use. Immobilization is a technique where an enzyme is trapped onto an insoluble inert support material so that the enzyme can be recovered and reused. Chitosan magnetic nanoparticles (CMNP) are used in this experiment as the support as it is cheap and readily available. Since coconut husk is insoluble, mass transfer phenomena remains a major bottleneck in hydrolysis due to limitations in the substrate to enzyme accessibility, especially when the enzyme is immobilized on an insoluble material like CMNP. If only mass transfer resistance is accounted, hydrolysis only occurs on the enzyme particles’ surface. The mass transfer coefficients obtained are 0.0000723, 0.0368, 0.0295 in respect of A. niger cellulase, T. reesei cellulase, and T. longibrachiatum xilanase. Higher coefficients values contribute proportionally to higher yield. If the reaction is assumed to occur uniformly within the spherical immobilized enzyme, then the substrate will diffuse molecularly through the enzyme, where internal mass transfer is no longer negligible. Thiele’s Modulus obtained are 2.197, 0.0368, 0.0795 in respect of A. niger cellulase, T. reseei cellulase, and T. longibrachiatum xilanase. A smaller value in Thiele’s Modulus (ϕ ≤ 1) shows that diffusion occurs at a faster rate than the enzymatic reaction.
Neem-based oil-in-water (O/W) emulsion as a biopesticide
Authors: Ramadhany Putri , Witono Judy Retti B. , Rosaria Regina
Published: February 2021

Neem tree (Azadirachta indica) is well-known to contain active components, such as azadirachtin (AZA), nimbin, and nimbidin that are potent to eliminate pesky insects. These active components can be found in large numbers in the neem oil. The favourable properties of neem oil to kill pests with minimum impacts to the ecosystem makes it veritably attractive to replace synthetic chemical pesticide. In this research, the neem oil is mixed with water and emulsifiers in the homogenizer to generate oil-in-water (O/W) emulsions. The droplet size, the size distribution, the stability, and the effectiveness of emulsion are analysed to determine the best formulation of neem-based biopesticide. The results showed that the formulation of 10%- w neem oil and 5%-w non-ionic emulsifier Lutensol® TO 6 produces the most stable emulsion with d32 of 0.50 μm. The fastest mortality rate for Musca domestica larvae is achieved at 20 ppm and 8 minutes with emulsion formulae of 10%-w neem oil and 5%-w non-ionic emulsifier Lutensol® TO 8.
Autocatalytic Hydrolysis of Palm Oil for Fatty Acid Production by Using Hydrothermolysis Process
Authors: Yulianto Mohamad Endy , Amalia Rizka , Paramita Vita , Hartati Indah , Nisa’ Qurrotun A’yuni Khoirun
Published: February 2021

As the world major leader in the palm oil production, Indonesia need to develop a new efficient technology to replace the conventional production process of fatty acid from palm oil. Auto catalytic hydrolysis reaction of palm oil in a hydrothermal reactor offers several benefits in fatty acid production. This research objective was to determine the rate constant of hydrothermal auto catalytic hydrolysis reaction of palm oil in fatty acid production. The Auto catalytic hydrolysis reaction of palm oil was conducted in several reaction temperatures (130- 150°C) at a different time (5-30 minutes). The research results show that at all the temperature applied, along with the increasing of reaction time, the fatty acid obtained were increasing also, while the highest fatty acid concentration was obtained from the auto catalytic hydrolysis reaction of palm oil performed at temperature of 130°C.
Analysis of Red Colorants and Heavy Metals in Lipstick at Traditional Market in Surabaya
Authors: Sumiyani R , Diatmika I K C , Muslimah N H , Rachmaniah O
Published: February 2021

Lipstick is classified as decorative cosmetics, generally, with many colours’ variance attracting the consumers. However, red is the favourites amongst them. Protecting the consumer’s health, lipstick should meet certain requirements which is registered by (National Agency of Drug and Food Control (Badan Pengawas Obat dan Makanan/BPOM). Regulation of BPOM No.HK.03.1.23.08.11.07517 of 2011 regulates prohibited red colorants such Rhodamine B. While at regulation of BPOM No.HK.03.1.23.07.11.6662 regulates a maximum level of heavy metals concentration. This study was conducted to determine the presence of Rhodamine B, Red Allure, and Amaranth as well as Pb and Cd in illegal brands of red lipstick at PXXX Market in Surabaya. The red colorants were identified with Thin Layer Chromatography (TLC)-densitometry while the metals, lead (Pb) and cadmium (Cd), were analysed with Inductively Coupled Plasma Spectrometer (ICPS). A validation method both for TLC-densitometry and ICPS were performed previously prior the analysis; meet the requirements for linearity, accuracy, precision as well as limit of detection (LOD) and limit of quantification (LOQ). Six illegal brands of lipsticks were identified at PXXX Market in Surabaya. One of them was qualitatively detected contains only Rhodamine B, 2 samples contain both Rhodamine B and Red Allure while the rest of 3 brands were contain Red Allure. None of them contain Amaranth. Hence, a quantitative analysis of Red Allure was further conducted. The Red Allure content in the identified red lipsticks was 34.19-187.88 mg/kg, below the maximum allowable content. In case of heavy metals, Pb and Cd. None of the lipstick’s samples contain both Pb and Cd.
Effect of Activated Carbon and Catalyst on Physical and Chemical Properties of Pyrolytic Oil from Microwave Assisted Pyrolysis of Automotive Paint Sludge (APS)
Authors: Za’bar Johan Ariff , Rahman Norazah Abd , Idris Siti Shawalliah
Published: February 2021

Automotive paint sludge (APS) contains valuable material which can be recovered by microwave-assisted pyrolysis as studied by previous researchers. In this study, combined application of microwave absorber and catalyst are studied in order to study the effect of both components in microwave-assisted pyrolysis of APS. Activated carbon and ZSM-5 acted as microwave absorber and catalyst, respectively were used to investigate their effect on pyrolytic oil produced from APS. By using One-Factor-At-Time (OFAT) analysis, results showed that at 1000W power level, 30 minutes radiation time, 6% activated carbon loading and 1.5% catalyst loading, the process was capable to produce highest oil yield of 7.75% pyrolytic oil as compared to other parameters. On the other hand, physical and chemical properties of pyrolytic oil produced via this process was also improved.
Rapid expansion supercritical solution (RESS) of CO2 as a green technology method for pineapple peels solid oil particle formation
Authors: Zainuddin N A , Mohamad N D , Rodzay R M
Published: February 2021

Current development using the technique of Rapid Expansion Supercritical Solution (RESS) in solid oil particle formation pineapple peel contains a great deal active pharmacological which are anti-inflammatory, anti-oxidants, and anti-cancer agent. Many researchers use the conventional technique such as hydro-distillation, supercritical fluid extraction, and soxhlet extraction in order to extract the valuable component in oil formed. However, these techniques have several disadvantages such as long extraction time, high usage of solvent and produce toxic residual which can harm the environment. The RESS technique is not as time consuming as it will directly produce oil in particle formation, instead of conventional technique that need to undergo further technique such as spray drying in order to produce solid oil particle. In this study the extraction was conducted using temperature 40, 45, 50, 55, 60°C and the pressure used were 3000, 4000, 5000, 6000 and 7000 psi at a constant flowrate of 24ml/min for 50 minutes extraction time. The extracted component in solid oil particle was analyzed using Gas Chromatography Mass Spectrometry (GCMS) and show that pineapple peels is rich in volatile components such as 1-Hexene, 4-methyl, Benzene, 1,1’-(1,2 cyclobutanediyl) bis-, trans, and 1-Buten-3-one, 1-(2-carboxy-4,4-dimethylcyclobutenyl).
The effects of UV-C and HNO2 mutagen, pH and the use of commercial fertilizers on the growth of microalgae Botryococcus braunii
Authors: Murprayana Ratnasari , Pukan Maria Stella Hadiyanti , Soedarmodjo Thea Prastiwi , Widjaja Arief , Wirawasista Hakun
Published: February 2021

Botryococcus braunii microalgae is a potential producer of biodiesel as an alternative fossil fuel because it has a high lipid content. This paper was conducted to determine the optimal mutation agent, microalgae resistance to changes in pH and, optimal nutrients from commercial fertilizers for the growth of Botryococcus Braunii. To find the best mutation agent, culture was planted in seawater media with Walne nutrient with UV-C and HNO2 exposure. The results showed that the optimal mutation agent was a mutation with UV-C exposure expressed by lipid productivity values. Furthermore, to see microalgae resistance to changes in pH, B. braunii was cultured in seawater media with Walne nutrients at various pHs, namely 3-8 with mutations of UV-C rays and without mutation agents. The results show that natural and mutated B. braunii microalgae grow optimally at pH 8. This also shows that mutated microalgae have better adaptability compared to natural microalgae, as evidenced by the number of natural microalgae cells that continues to decrease with a decrease in pH. The final goal is to find the optimal nutrient for growth in B. Braunii from commercial fertilizer. Culture was planted in seawater media with various concentrations of commercial fertilizer, for 7 days of culture, the results showed that each nitrogen source had a different effect on the growth of microalgae