bluuebunny/crossref_metadata_2025 huggingface dataset:
Flux-driven nonlinear fluid simulations of ion thermal confinement change by external torque
Authors: Jhang Hogun , Kim S. S.
Published: November 2019

From nonlinear flux-driven fluid simulations, we show that the external torque has a profound influence on ion thermal confinement. A key parameter controlling the confinement change is found to be the ratio of the net external torque to the applied power input. For a given value of external torque, the ion temperature profile destiffening and the corresponding confinement enhancement occur when the ratio is below a threshold value. This confinement improvement is shown to originate from the increase in the zonal flow shearing rate due to the conversion of parallel flow compressibility to zonal vorticity. Confinement degradation and the restoration of profile stiffness arise beyond the critical value of the ratio due to the onset of the parallel velocity gradient instability. This result implies the existence of an optimal torque value for the given heating power to maximize the thermal confinement.
Two-phase flow simulation of scour beneath a vibrating pipeline during the tunnel erosion stage
Authors: Tofany Novan , Low Ying Min , Lee Cheng-Hsien , Chiew Yee-Meng
Published: November 2019

A new numerical model is developed to simulate and investigate scour beneath a vibrating pipe during the tunnel erosion stage. This study is motivated by the fact that existing numerical models are not able to properly simulate scour under a vibrating pipeline, and the underlying physical mechanisms are not well understood due to the complex fluid-structure-sediment interaction. The present model incorporates the hybrid fictitious domain-immersed boundary method into a recently developed rheology-based two-phase model. The present model is validated against published experiment results of flow beneath a vibrating pipeline near a rigid boundary and scour beneath a fixed pipe. The flow velocity at the gap and the scour profile beneath the pipe are generally well produced by the model. Subsequently, the proposed model is applied to simulate scour under a vibrating pipe with different vibration amplitudes and frequencies. Among other things, it is found that maximum pipe acceleration has a dominant effect on the underlying physics that induce scour, irrespective of the combination of the vibration amplitude and frequency. An explanation for this finding is proposed based on various quantitative simulated results.
Optical excitations of chlorophyll a and b monomers and dimers
Authors: Preciado-Rivas María Rosa , Mowbray Duncan John , Lyon Keenan , Larsen Ask Hjorth , Milne Bruce Forbes
Published: November 2019

A necessary first step in the development of technologies such as artificial photosynthesis is understanding the photoexcitation process within the basic building blocks of naturally occurring light harvesting complexes (LHCs). The most important of these building blocks in biological LHCs such as LHC II from green plants are the chlorophyll a (Chl a) and chlorophyll b (Chl b) chromophores dispersed throughout the protein matrix. However, efforts to describe such systems are still hampered by the lack of computationally efficient and accurate methods that are able to describe optical absorption in large biomolecules. In this work, we employ a highly efficient linear combination of atomic orbitals (LCAOs) to represent the Kohn–Sham (KS) wave functions at the density functional theory (DFT) level and perform time-dependent density functional theory (TDDFT) calculations in either the reciprocal space and frequency domain (LCAO-TDDFT-k-ω) or real space and time domain (LCAO-TDDFT-r-t) of the optical absorption spectra of Chl a and b monomers and dimers. We find that our LCAO-TDDFT-k-ω and LCAO-TDDFT-r-t calculations reproduce results obtained with a plane-wave (PW) representation of the KS wave functions (PW-TDDFT-k-ω) but with a significant reduction in computational effort. Moreover, by applying the Gritsenko, van Leeuwen, van Lenthe, and Baerends solid and correlation derivative discontinuity correction Δx to the KS eigenenergies, with both LCAO-TDDFT-k-ω and LCAO-TDDFT-r-t methods, we are able to semiquantitatively reproduce the experimentally measured photoinduced dissociation results. This work opens the path to first principles calculations of optical excitations in macromolecular systems.
Quenching of the Sm2+ luminescence in NaMgF3:Sm via photothermal ionization: Alternative method to determine divalent lanthanide trap depths
Authors: Schuyt J. J. , Williams G. V. M.
Published: November 2019

Photoluminescence and radiophotoluminescence measurements were performed on the promising dosimeter compound NaMgF3 doped with Sm at different temperatures. Quenching of the Sm2+ photoluminescence during continuous 448 nm optical stimulation into the Sm2+ 4f 55d1 level was observed at high temperatures. We attribute this to photothermal ionization from the Sm2+ 4f 6(7F0) ground state to the NaMgF3 conduction band followed by nonradiative decay to the Sm2+ ground state. This was confirmed by X-ray-induced radiophotoluminescence, Sm3+ + e− → Sm2+, where the valence conversion was reversed by simultaneous thermal and optical stimulation. From these measurements, we deduce that the energy from the Sm2+ 4f 55d1 level to the conduction band is 1.2 eV and the energy from the Sm2+ 4f 6(7F0) ground state to the conduction band is approximately 4.0 eV. Thus, we provide an alternative method to determine the trap depths of divalent lanthanides in insulators, which is of critical importance in the development of commercially relevant luminescent materials.
Heterogeneities in electricity grids strongly enhance non-Gaussian features of frequency fluctuations under stochastic power input
Authors: Wolff Matthias F. , Schmietendorf Katrin , Lind Pedro G. , Kamps Oliver , Peinke Joachim , Maass Philipp
Published: October 2019

Stochastic feed-in of fluctuating renewable energies is steadily increasing in modern electricity grids, and this becomes an important risk factor for maintaining power grid stability. Here, we study the impact of wind power feed-in on the short-term frequency fluctuations in power grids based on an Institute of Electrical and Electronics Engineers test grid structure, the swing equation for the dynamics of voltage phase angles, and a series of measured wind speed data. External control measures are accounted for by adjusting the grid state to the average power feed-in on a time scale of 1 min. The wind power is injected at a single node by replacing one of the conventional generator nodes in the test grid by a wind farm. We determine histograms of local frequencies for a large number of 1-min wind speed sequences taken from the measured data and for different injection nodes. These histograms exhibit a common type of shape, which can be described by a Gaussian distribution for small frequencies and a nearly exponentially decaying tail part. Non-Gaussian features become particularly pronounced for wind power injection at locations, which are weakly connected to the main grid structure. This effect is only present when taking into account the heterogeneities in transmission line and node properties of the grid, while it disappears upon homogenizing of these features. The standard deviation of the frequency fluctuations increases linearly with the average injected wind power.
Computational and experimental identification of hydrogen defect vibrational modes in zinc sulfide
Authors: McCloy J. S. , Wolf W. , Wimmer E. , Poisl W. H. , Zelinski B. J. J.
Published: November 2019

The characteristic extrinsic infrared absorption in bulk chemical vapor deposited (CVD) ZnS has been unambiguously identified. High resolution absorption measurements and ab initio vibrational calculations identify the absorption of 1760–1580 cm−1 as due to defects of the form (ZnHn)S, with n = 3 being the highest concentration. Multiple absorption peaks in this spectral region are due to Zn-H stretching from different bond lengths. Phonon spectra calculations of hexagonal ZnO impurities do not account for the spectral position of the absorption without three-phonon processes and thus are unlikely to be responsible for the extrinsic infrared absorption in CVD ZnS. This work shows the complementary utility of computational and experimental work for identifying defect structures in semiconductors.
Photo-charging polymeric sodium-ion cell based on YSZ/PVDF film
Authors: Khatun Farha , Thakur Pradip , Bagchi Biswajoy , Das Sukhen
Published: October 2019

A cost-effective, light-weighted, and easy to handle photochargeable Na-ion power cell (NPPC) has been demonstrated by integrating solar active solid electrolyte poly(vinyl alcohol)-carbon black-V2O5-Na2SO4 and a high dielectric YSZ/PVDF film in a very simple and unique way. An open circuit voltage of ∼1.18 V is obtained under photocharging of the NPPC by light with an intensity of ∼110 mW/cm2. The discharging phenomenon is investigated at a constant discharge current density of ∼0.63 mA/cm2. The reversible charging-discharging nature of the device is recorded repeatedly for 200 cycles to investigate the storage capacity. A maximum capacitance of ∼ 2.84 mF/cm2 is obtained with an energy density and a power density of ∼5.6 mWhr/m2 and ∼ 7.4 W/m2, respectively. The high storage impact of NPPC is realized in practical by glowing blue light emitting diodes for two days with high intensity.
Thermal effects in a triplet and beam interaction in a plasma
Authors: Peter E. , Pakter R. , Rizzato F. B. , Marini S.
Published: November 2019

The dynamics of three interacting waves fulfilling the frequency and wavenumber matching conditions can be dramatically modified if a charged particle beam is added to the system. Energy is exchanged not only among the waves but also between the particles of the beam and the waves. In the present work, a model that includes these interactions is revisited, allowing a more realistic case where the beam has an initial velocity distribution. This study aims to present the role of this thermal effect over the system at the beginning of the dynamics and after the breakdown of the laminar regime of the particle beam.
Photobleaching statistics in single-molecule on-/off-time distributions
Authors: Yang Haw , Li Hao , Liu Tao
Published: November 2019

The on- and and off-time distributions from fluorescence single-molecule experiments are widely used to extract kinetics parameters with the goal to provide a quantitative description for the molecule’s behavior on the ensemble level. Such experiments are inevitably influenced by photobleaching, where the fluorescent probe transitions to a nonemissive state. Yet, it appears that few reports went beyond acknowledging this unavoidable complication; in fact, it has so far been ignored when evaluating off-time distributions. Here, we present a theoretical framework that allows the derivation of analytical equations in which photobleaching kinetics are rigorously incorporated. Unexpectedly, our results indicate that the off-time distribution should be nonexponential even when all the rate processes are single exponential. With the analytical theory understood and demonstrated as easy to implement, such ubiquitous photochemical processes can now be readily included in routine experimental analyses.
Identification of critical residues for the catalytic activity of ComQ, a Bacillus prenylation enzyme for quorum sensing, by using a simple bioassay system
Authors: Hirooka Kazutake , Shioda Saki , Okada Masahiro
Published: October 2019

Bacillus ComQ participates in the biosynthesis of a quorum-sensing signaling molecule (ComX pheromone) through catalyzing the prenylation at a Trp residue of the precursor peptide (pre-ComX) with geranyl diphosphate (C10 type) or farnesyl diphosphate (C15 type). We hypothesized that several residues specifically conserved among either type of ComQs are important for their substrate specificities. Using a simple bioassay, we revealed that Phe63, Asn186, and Gly190 in ComQRO-E-2 (C10 type) were nondisplaceable to Ser63, Gly186, and Val190, the corresponding residues in the C15-type ComQ, respectively. A three-dimensional model suggested that the 186th and 190th residues are involved in the pre-ComX binding. In vitro analysis showed that substitution of Phe63 with Ser in ComQRO-E-2 significantly reduced the geranylation activity but substantially enhanced the farnesylation activity, whereas substitution of Ser63 with Phe in ComQ168 (C15 type) reduced the farnesylation activity. Therefore, the 63rd residue was found to be significant for the prenyl-substrate preference.

Abbreviations: GPP: geranyl diphosphate; FPP: farnesyl diphosphate; IPP: isopentenyl diphosphate; GGPP: geranylgeranyl diphosphate; FARM: first aspartate-rich motif; SARM: second aspartate-rich motif; β-Gal: β-galactosidase; TBABG: tryptose blood agar base supplemented with glucose; X-gal: 5-bromo-4-chloro-3-indolyl-β-D-galactoside
Student understanding of Fermi energy, the Fermi–Dirac distribution and total electronic energy of a free electron gas
Authors: Justice Paul , Marshman Emily , Singh Chandralekha
Published: November 2019

We investigated the difficulties that physics students in upper-level undergraduate quantum mechanics and graduate students after quantum and statistical mechanics core courses have with the Fermi energy, the Fermi–Dirac distribution and total electronic energy of a free electron gas after they had learned relevant concepts in their respective courses. These difficulties were probed by administering written conceptual and quantitative questions to undergraduate students and asking some undergraduate and graduate students to answer those questions while thinking aloud in one-on-one individual interviews. We find that advanced students had many common difficulties with these concepts after traditional lecture-based instruction. Engaging with a sequence of clicker questions improved student performance, but there remains room for improvement in their understanding of these challenging concepts.
Soft x-ray emission from laser-produced strontium ions
Authors: Miyazaki Takanori , O’Sullivan Gerry , Dunne Padraig
Published: November 2019

Soft x-ray spectra, in the range from 2 nm to 9 nm, were recorded from strontium plasmas formed by pulses from 20 ps, 170 ps and 5.5 ns Nd:YAG lasers operating at the fundamental wavelength of 1064 nm. Features due to 3d–4p and 3d–4f transitions were identified by comparison with spectra from adjacent ions and atomic structure calculations with both the Cowan code and the Flexible Atomic Code. As in the spectra of ions of other elements in the fifth row of the periodic table, resonant lines 3d

n
–3d

n−14p
1, 3d

n
–3d

n−14f
1 and satellite lines 3d

n−14s
1–3d

n−24s
14p
1, 3d

n−14s
1–3d

n−24s
14f
1 of Δn = 1 were observed over the 3.0–8.5 nm region, emitted by 10+ to 19+ ions. These Δn = 1 transitions provide a range of narrow band emission features which may match to specific multi layer combinations for reflective optics in the extreme ultraviolet region of the spectrum.
Two-dimensional interactive media for fourth grade students
Authors: Wahyuningtyas D T , Yuniasih N , Sesanti N R , Hudha M N
Published: October 2019

The use of advanced technology as instructional media can facilitate students’ understanding about instructional materials. The purpose of this research is to develop two-dimensional interactive media for fourth grade students. To this end, this study employed Thiagarajan’s Four-D (Define, Design, Develop, and Disseminate) model. Data were analyzed descriptively, both qualitatively and quantitatively. Data analysis was performed using qualitative and quantitative descriptive data analysis techniques. The results revealed that two-dimensional interactive media was deemed valid by experts with an average score of 4.5 and applicable for teaching elementary school students. Elementary students responded positively to the use of the interactive media and their understanding about two-dimensional instructional materials improved.
Learning results dribbling handball through the application of methods of play
Authors: Ruslan R , Hamdiana H
Published: October 2019

This Research action research is to improve the skills of dribbling the ball of the hand through the application of the method of play. This action research studies using qualitative approach. This research is numbered 20 people. To measure and find out the results of the study with handball dribbling test. The test results before the given action (pre-test) results of 6 students (30%) reached a standard learning of completeness to the value of the average student 57.90, the results obtained are still not as expected so that the given action through method of play. Test on cycle I obtained results, i.e. 14 students (70%) have reached a standard learning of completeness students with an average score of 71.95.Learning continues to cycle II and the results of tests obtained the results of 17 students (85%) have reached a standard learning of completeness students with the average value of 82.05 and 15% (3 students) have not yet reached a standard learning of completeness with the average student 81.05. The results of this research it can be concluded that: (1) the method of play can create an atmosphere of student learning that is engaging and fun, (2) the application of the method of play can improve learning results dribbling handball in physical education.
Packaging science and local wisdom in digital devices for primary school students: Challenges and obstacles
Authors: Nasrudin D , Irwansyah F S , Sugilar H , Ramdhani M A , Aulawi H
Published: October 2019

Today the use of digital media in science learning has become a demand and necessity, not least in the elementary school level. However, the use of digital devices as a medium of instruction in primary schools should have positive impacts and surplus value, one of them reviving and maintaining local wisdom. This paper aims to present of outlining the challenges and obstacles to pack science learning and local wisdom in digital devices. The research method is qualitative descriptive through stages of elementary school curriculum analysis, local wisdom value analysis and Focus Group Discussion (FGD) to find the packaging formula both in science learning. The results show that local wisdom values of a region can integrate into relevant science learning. Appropriate techniques are required in packing the learning design in digital devices by considering the competence factor to be built, the adequacy of the content, the value of local wisdom and the ease of the media to be accessed.
Improve the ability of understanding mathematics and confidence of elementary school students with a contextual approach using VBA learning media for Microsoft Excel
Authors: Bernard M , Akbar P , Ansori A , Filiestianto G
Published: October 2019

The main problem of this research is the lack of students understanding the ability and mathematical self-confidence for mathematics learning in elementary school students in Indonesia. Lack of students understanding of mathematics is caused by the learning process in school. Teachers still use conventional learning in the learning process. Also, the basic skills aspects of students also affect the ability of math skills. Furthermore, the learning process with a contextual approach assisted by VBA Learning Media (Visual Basic Application for Excel) gives positive influence on students both regarding mathematical understanding and self-confidence. The data processed in this study is from the post-test score. This score arises from both the experimental class group and the control class group. Then, the data processed using SPSS 22 and Microsoft excel. Data were analyzed using the t-test statistic. The final result of this study concludes achievement and improvement of mathematical understanding ability and Self Confidence students learning with contextual approach supported by VBA (learning media Visual Basic Application for Excel) are better than students who get conventional learning.
The use of the Synthesia application to simplify Angklung learning
Authors: Julia J , Kurnia D , Isrokatun I , Wulandari H , Aisyah I
Published: October 2019

The majority of students in the department of pre-service elementary school teacher cannot read the notation correctly. However, they have a strong motivation to learn music composition, such as angklung music composition. This paper aims to analyze the development of students who are members of the music community in studying the composition of angklung music by using the Synthesia application. The research method was carried out in the following stages: (1) making angklung musical composition in the type of MIDI (Musical Instrument Digital Interface) files; (2) input MIDI files for the Synthesia application; (3) setting up the Synthesia application; (4) learning Angklung using the Synthesia application; and (5) evaluating the learning process. Research subjects were students who were members of the music community on campus, so that their age and musical abilities were very heterogeneous. The research subjects were 15 people, as many as one angklung player group. The results showed that angklung learning for students who had the low notation reading ability, became easier by using a touch of technology. Students can read, visual-based notation correctly. It can be concluded; that technology can provide the convenience in the process of learning music composition, especially in angklung music composition.
Thematic learning design development: STEM model through water play activity
Authors: Nur L , Hamdu G , Mulyadiprana A , Nuraeni E , Yulianto A
Published: October 2019

2013 curriculum is a curriculum model that can integrate skills, themes, conceps, and topics in both within disciplines, across several disciplines and within and across learners. The enactment of the 2013 curriculum will have an impact on the way learning will be designed and implemented by teachers in the classroom. The lessons that are held are not necessarily rigid, absolute housed in the classroom, trapped by an enclosed wall and a short time. Instead learning should be flexible, fun, stimulating student activities and can provide meaningful experiences for students so that students can be creative, productive, and innovative. The purpose of this research is to develop STEM model learning design through water game activity in elementary school. The development of thematic teaching design is done by several experiments to several schools by adopting DBR (Design-Based research) approach. The resulting product is a STEM thematic learning tool based on a water game activity as the implementation of the 2013 curriculum. One of the major reasons for developing this learning tool is to get an example of a learning device integrated with the game. Fun learning but still oriented to learning materials so that learning can be a weapon that will develop student competence.
The design of student mathematical representation instrument on problem solving reviewed from introvert-extrovert personality
Authors: Selvia N , Awaludin A A R , Andrari F R
Published: October 2019

This study aims to determine whether the instrument to be used is feasible or not to obtain research data. The research instrument used is the introvert-extrovert personality testand math-type problem-solving test. The introvert-extrovert personality testconsist of 17 questionsand the math-type problem-solving consist 2 types of questions, that is TPM I and II. The feasibility test of the introvert-extrovert personality instrument includes content validity, internal consistency, and reliability. While the feasibility test of the mathematical problem solving test instrument only used the validity of the content. For the validity of the contents of each test, conducted through expert judgment is the assessment made by experts. The number of respondents who took the test for the instrument test was 35 students. The respondents are students of secondary school in East Jakarta. The results of the instrument feasibility test show that: 1) Introvert-extrovert personality instruments have 17 statements that are eligible to retrieve the research data, and 2) The mathematical problem solving test instrument with linear equation system topic is feasible to use with some revisions from the expert judgment.
The mathematics communication of students in learning based on ethnomathematics Rejang Lebong
Authors: Herawaty D , Gusri S A , Saputra R , Liana E , Aliza F
Published: October 2019

The objective of study was to describe the metacognition of students in the mathematical communication process of high school students in learning mathematics oriented ethnomathematics Rejang Lebong. This research method is descriptive qualitative research, with the subject of the student of Senior High School in Rejang Lebong. The results showed that subjects with high cognitive level were able to think metacognitive with the mathematical communication process through planning, monitoring and evaluating the thinking process in the mathematical communication process. Subjects with cognitive level are doing mathematical communication in the form of planning, and monitoring but not exactly in evaluating the thinking process. While subjects with low cognitive level can make planning but cannot monitor and cannot evaluate the thinking process.
The REACT strategy and discovery learning to improve mathematical problem solving ability
Authors: Widada W , Herawaty D , Mundana P , Agustina M , Putri F R , Anggoro A F D
Published: October 2019

The purposes was to examine the comparison of problem solving abilities and critical thinking abilities for students who are taught with the REACT learning strategies and conventional learning. A quasi-experimental study with non-equivalent pretest-posttest design was applied in this study. The sample of this study was 64 students of Senior High School Kota Bengkulu. This research instrument is a test of problem solving skills and a critical thinking ability test. The result of the research was the ability of students taught with REACT strategies was higher than students taught with traditional learning. Also, the ability of students taught with guided discovery models was higher than students taught with traditional learning.
Students’ reading skills related to science learning using big book media
Authors: Saefuddin A , Malik A , Maulidah I R , Chusni M M , Salahudin A , Carlian Y
Published: October 2019

Reading skill is an active receptive language skill to get a message from the writer in the written variety. This research is based on the phenomenon reading skill of students in Madrasah Ibtidaiyah Bongas IV Cililin related to science including low category. This study aims to determine the enhancing reading skills of a student after applying Big Book media in science learning. The research method used is a pre-experiment design with one group pretest-posttest design. The subjects of this study are the third-grade students of Madrasah Ibtidaiyah Bongas IV Cililin selected by purposive sampling technique amounted to 22 people. Student reading skill is measured through multiple choice test and supporting instrument in the form of an observation sheet to know student and teacher activity in using Big Book media. The results showed that there was enhancing reading skill of student with normalized gain  including high category. Based on the paired sample t-test, using Big Book media in science learning can improve the reading skills of the student. The average results of observation sheet analysis in the book Big Book to improve reading skills of the student at every meeting good category. It can be concluded that the use of Big Book in science learning can be an alternative to enhancing reading skills of the student. Thus, Big Book media can motivate students to have a high read culture.
Use of flannel puzzle to improve the initial of counting ability
Authors: Mulyati M , Yufiarti Y , Supriyati Y , Suharti S
Published: October 2019

The initial of counting ability is essential for children to solve problems in everyday life. This study aims to describe the use of Flannel Puzzle in improving the initial of counting ability in Renggali one of the early childhood education institutions. This action research on 15 student who were the subject of research. Data are analysed by descriptive qualitative and quantitative. Stages of planning, action, observation, and reflection. The results of the study conclude that: flannel puzzles can improve initial of counting ability. By using the flannel puzzle the initial of counting ability of students can increase. Students’ abilities increase from 44.66% before action and increased in the first cycle around 49.25% and in the second cycle became 90.16%.
Design of problem-solving questions for measuring student’s mathematical thinking type representation
Authors: Irenika I , Susanti E , Hiltrimartin C , Hapizah H , Meryansumayeka M
Published: October 2019

This study is design research aimed to describe the design result of problem-solving question that can be used to measure mathematical thinking type representation. The process of this study consists of five stages, namely: preliminary design, focus group discussions (FGD), trials, observation and interview, and retrospective analysis. The subjects of this study are three students. The technique for data analysis was qualitative. The instrument consists of test and directive interview. Based on preliminary design and FGD stages, researchers have designed two problem-solving questions. Based on the results of the trials, observations and interviews, all these questions can lead students’ mathematical thinking type representation. This is illustrated by the results of research subjects’ answers when working on questions that showing symbolic representation, numeric representation, and visual representation. Symbolic representation is seen from the completion of students who use symbols to solve problem number 1 and 2. Visual representation is seen from students resolve the problems using images to solve problem number 2. Numeric representation is seen from students solving problems using a trial and error strategy and then doing mathematical calculations to make sure the correctness of answers. This is done by students in working on questions number 1.
Problem posing skill of elementary school students
Authors: Isrokatun I , Syahid A A , Putri H E , Julia J , Sunaengsih C
Published: October 2019

Children generally have a high level of curiosity, hence they often ask many questions repeatedly. Their high level of curiosity is ought to be developed by adults, which includes their parents and teachers. However, in reality, the older the children get, the more reluctant they become to ask questions due to many reasons. This results in the weakening their confidence to ask questions and diminishing their problem posing skill. By employing ADDIE (Analyzing, Designing, Developing, Implementing, and Evaluating) method, this research was conducted to illustrate elementary school students’ problem posing skill. The respondents comprised elementary school students aged 10-12 years. The research discovered that the students’ problem posing skill still needs to be developed by providing a certain facilitation that allows the students to be more confident to ask questions. The research also found that the confidence to ask questions can be encouraged with the utilization of a student worksheet that provide situations instead of problems.
Problem-based learning and ethnomathematics on mathematical understanding
Authors: Perdana D C , Isrokatun I
Published: October 2019

Mathematical understanding is very important aspect for students in elementary school. However, the mathematical understanding is still low. Innovative learning mathematics is chosen as a solution to improve mathematical understanding by using problem-based learning and ethnomathematics. The purpose of this research is to know how the effect of problem-based learning approach with ethnomathematics on mathematical understanding. The method used in this research was Four-D models which consists of: Defining, Designing, Developing, and Disseminating. The subjects of this research consisted of 83 students from fourth grade elementary school. The selected samples of research will be divided into experimental class and control class. The instruments used were the mathematical understanding test, and student response questionnaire. The result of the research showed problem-based learning and ethnomathematics have a positive effect on mathematical understanding. Problem-based learning and ethnomathematics is better than conventional learning to improve mathematical understanding. The new finding in this research from the questionnaire result was students prefer modern culture rather than local culture.
Elementary school teacher’s understanding on the scientific approach in natural science and mathematics subjects
Authors: Rostika D , Prihantini P
Published: October 2019

This research is motivated by the urgency of applying a scientific approach to be able to equip students’ skills in facing the challenges of 21st century life. With the support of the results of previous research, this research aims to describe the understanding of elementary school teachers about the scientific approach and its implementation in the learning of natural sciences and mathematics subjects. The method of this research applied quantitative descriptive research. To be able to apply the scientific approach, teachers are not only armed with understanding but need to be supported by efforts to find other knowledge that can improve their self-efficacy. Most teachers know the scientific approach, but have not been able to apply the teaching and learning process systematically.
Steady on MHD Heat and Mass Transfer Flow of an Inclined Porous Plate in the Presence of Radiation and Chemical Reaction
Authors: Sandhya A. , Reddy G.V.Ramana , Deekshitulu G.V.S.R.
Published: October 2019

In the present paper steady on MHD heat and mass transfer flow of a viscous incompressible fluid flow through a porous medium in the presence of radiation, heat source and chemical reaction effects are considered. The set of non linear differential equations can be solved analytically. Effects of various parameters like magnetic parameter, permeability parameter, Grashof number, modified Grashof number, radiation parameter, heat source parameter, Prandtl number, Schmidt number, chemical reaction and an angle of inclination on the velocity, temperature and concentration profiles as well as the skin friction, Nusselt number and Sherwood number are discussed qualitatively and shown graphically.
Locally Rotationally Symmetric Bianchi Type-I Cosmological Model in f(R,T) Gravity
Authors: Santhi M.Vijaya , Gusu Daba Meshesha , Rao V.U.M. , Suryanarayana G.
Published: October 2019

In this paper, we have investigated a spatially homogeneous locally rotationally symmetric Bianchi type-I space-time with cosmological term Λ in presence of perfect fluid distribution in f (R,T ) gravity theory. We have derived explicitly the field equations of the theory and obtained the exact solution of field equations by employing a periodic varying deceleration parameter, which is a unique feature of the model. We have also performed the analysis of the model such as the equation of state parameter, pressure, energy density, density parameter and jerk parameter which are significant in the discussion of cosmology. Some physical and geometrical properties of the model have also been discussed along with the graphical representation of various parameters. We obtained the presence of quintessence and phantom regions based on chosen parameters. It is observed that the deceleration parameter exhibits a smooth transition from early deceleration to late time acceleration of the universe and oscillate based on chosen parameters. We have observed that the presented model is compatible with the recent cosmological observations.
Soret and Dufour Effects on MHD Convective Flow Past a Vertical Plate Through Porous Medium
Authors: Dhanalakshmi .M , Jyothi .V , Jayarami Reddy .K
Published: October 2019

The objective of the present paper is to investigate the soret and dufour effect of Kuvshinshiki fluid on MHD free convection flow past a vertical porous plate with heat and mass transfer in the presence of chemical reaction. The velocity, temperature and concentration are obtained by using a perturbation technique. The results have been discussed graphically and numerically for various values of the flow parameters by using Matlab.
Ferro electric, ferro elastic & magneto electric polarizability domain and tensor pairs of magnetite (Fe3O4)
Authors: Surendra Talari
Published: October 2019

The present work is based on group theoretic analysis of crystal structures. Group theory can be employed to a variety of problems in physics and chemistry. It plays a major role in the solution of solid state physics problems. The concept of symmetry plays an important role in our physical environment. The symmetry of a molecule can be used to determine various physical properties of a crystal using group theoretical methods. The applications of magneto-electric devices lie in the regions of millimeter and sub-millimeter wavelengths and in the areas of reducing electrical conductivity, improving dielectric magnetic or magneto-electric properties by solid solutions improving optical quality and obtaining larger crystals. Ferro-electric, Ferro-elastic and magneto-electric polarized domain pairs and tensor pairs are calculated using coset decomposition and double coset decomposition respectively for the crystal magnetite (Fe3O4). While considering Ferro-electric and Ferro-elastic properties only ordinary point group m3m is considered as prototypic point group since they are non-magnetic properties. In case of magneto-electric polarizability grey group m3m1 is taken as prototypic point group.
Some Bianchi Type Bulk Viscous String Cosmological Models in f(R) Gravity
Authors: Santhi M. Vijaya , Naidu T. Ch. , Papa Rao D. Ch.
Published: October 2019

In this paper, we investigate bianchi type II, V III and IX Bulk viscous string cosmological models in the context of f(R) gravity. Here, we obtained the solutions of the field equations in the presence of cosmic strings under some specific possible physical conditions. Some physical and geometrical features of the models are also discussed.
Bianchi type-III, V and VI0 generalized ghost dark energy models with polytropic gas in Brans-Dicke theory of gravitation
Authors: Rani N. Sandhya , Sireesha K.V.S. , Rao V.U.M.
Published: October 2019

This paper elaborates the homogeneous and anisotropic Bianchi type-III, V and VI0
space times filled with matter and generalized ghost dark energy components in the framework of Brans-Dicke (Phys. Rev. 124, 925 1961) theory of gravitation. The behavior of generalized ghost dark energy for Bianchi type-III, V and VI0
background is discussed. The solutions of the field equations obtained using following two assumptions: (i) shear scalar of the model is proportional expansion scalar, which leads to a relation between the metric, (ii) scalar field in the Brans-Dicke theory is a function of average scale factor of the models. We have further established a correspondence between the generalized ghost dark energy models with the polytropic gas dark energy model. We also reconstructed the potential and dynamics of the scalar field. We discuss some physical and geometrical properties of the obtained models which are found to be consistent with recent observation.
Opportunities for Local Energy Supply in Norway: A Case Study of a University Campus Site
Authors: Backe S , Sørensen Å L , Pinel D , Clauß J , Lausselet C
Published: October 2019

Neighbourhoods can contribute to climate change mitigation by supplying and/or facilitating renewable energy sources (RES). In this context, we evaluate opportunities related to the energy system of a Norwegian university campus, Campus Evenstad, by quantifying monetary value of local energy resources like solar photovoltaics (PV) and a bio-based combined heat and power (CHP) plant in a cost analysis. Environmental value is discussed regarding operational control of energy units to minimize emissions. Using mixed integer linear programming (MILP), we also present results from an investment analysis for local thermal and electric energy system to achieve different levels of emission compensation. Results show that local electricity supply generates most monetary value through saved costs related to reduced power grid import, and that solar PV is the most cost-efficient resource to achieve compensation of GHG emissions.
Process-related risks in refurbishment of dwellings using prefabricated wall elements with integrated PV and ventilation ducts
Authors: Holøs S B , Lukina V , Hauge Å. L. , Thunshelle Kari
Published: October 2019

Prefabricated façade elements with integrated technical infrastructure is an attractive technology for refurbishment of existing dwellings. Heating and cooling demand can be reduced, local energy production introduced, and indoor air quality be improved, with disturbance to the tenants and building site being small and of short duration compared to more traditional building processes. On the other hand, unexpected events could largely reduce these benefits. Thus, risk management of the building process is of great importance. Focus group interviews and workshops were arranged before and after the building phase in a pilot project using such elements in Oslo, Norway. Representatives of building owner, design team and contractor contributed actively at the workshop. In a pre-building phase workshop, a range of hazards were identified and prioritized using a participative process facilitated by a neutral moderator. A large proportion of the prioritized risks in the building phase were connected to the renovated flats being occupied during the renovation. Other significant identified risks related to transport and logistics, and undetected challenges in the existing construction. Mitigation included prioritizing tenant information, including direct dialog, and increasing the presence of on-site workforce both for coordination with tenants and in order to respond quickly to unforeseen events. The participants emphasized that an open, cooperative processes with a high degree of trust and sense of a common goal had been important for the robust design that was developed prior to the workshop. During the retrospective evaluation, the participants concluded that the risk mitigation procedures had been successful in preventing some events as well as reducing the consequences of others. However, some of the measures to mitigate an identified risk of rain intrusion were inadequate, and it was acknowledged that the combination of bad weather and long working days could have identified this as preventable.
Life cycle assessment for Zero Emission Buildings – A chronology of the development of a visual, dynamic and integrated approach
Authors: Wiberg A Houlihan , Wiik M. Kjendseth , Auklend H , Slåke M Løkland , Tuncer Z , Manni M , Ceci G , Hofmeister T
Published: October 2019

Current regulations to reduce energy consumption, and GHG emissions from buildings have focused on reducing operational impacts [1] This paper addresses the specific challenge of increasing complexity and decreasing usability when dealing with the level of detail required when modelling life cycle assessment (LCA) and integrating embodied emission calculations in the design process of a ZEB. It is well known that architectural design processes inherently have high degrees of complexity, and this paper investigates how the use of information and communication technology (ICT) in the design process can have a great impact on reducing GHG emissions and increasing sustainability in ZEBs. Visualisation is an invaluable tool to communicate complex data in an interactive way that makes it easier for non-expert users to integrate LCA thinking early and throughout the design process.

The paper presents a chronology in the development of a more visual, integrated and dynamic approach involving the use of parametric LCA models for decision-support purposes. Such an approach provides the designer with a direct link between the 3D digital model and embodied emissions data contained in the ZEB Tool to perform life cycle GHG emission calculations of buildings. Integrating LCA in a more visual and easily understood way in the holistic design process can also influence more tangible material choices in terms of, for example, architectural tectonics or cultural heritage. This allows designers the possibility to choose, for example, durable or natural materials with the lowest environmental impact or innovative materials with high or low associated emissions and consider these holistically early in the design phase when the level of design freedom is greater. The extent to which existing ICT tools and User Interfaces (UI), such as dashboards, can provide dynamic visual feedback on selected parameters, including LCA, in the design process of zero emission buildings, is discussed. The paper presents two ‘proof of concept’ dashboards to visualise LCAs at the building (ZEB) and neighbourhood (ZEN) scale. Both approaches are currently being further developed in The ZEN research centre to visualise, analyse and model the data at different scales for different ZEN Key Performance Indicators (KPIs) using visualisation and immersive technologies, such as Extended Reality (XR) technologies including Virtual Reality (VR) and Augmented Reality (AR).
Disturbance Characteristics of the Off-Grid Photovoltaic System in the Frequency Range from 9 - 150 kHz with Changing Solar Irradiance and Shading Area
Authors: Muhammad N , Sudiarto B
Published: October 2019

A solar power plant converts light into electricity using photovoltaics. It uses an inverter to convert DC to AC current to be connected to an AC load. Increasing use of solar panels in household application results in an increase in the use of inverters, in which some might due to the fact that inverters can produce disturbances at a frequency between 9-150 kHz. This study is focused on observing the disturbance characteristics of an off-grid photovoltaic system due to variations of irradiation and shading in the frequency range from 9 -150 kHz. It is expected that the output of this observation can provide a reference for research in determining the effects on electric power system. This observation provided a shading effect of 0%, 25%, 50%, 75%, and 100% of the photovoltaic area and then conducted observation based on two solar irradiation conditions. Based on the observations, it is identified that in general there are 3 frequency ranges of dominant disturbances, they are: 20-25 kHz, 72-73 kHz, and 144-146 kHz. Their voltage disturbance will decrease with increasing shading area, where at shading conditions of 25% and 50% they will have a value voltage disturbance that tends to be the same as that in the 3 dominant frequency ranges.