bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cognition processes of student with low functioning autism in solving mathematical problem
Authors: Fauziyah N , Budayasa I K , Juniati D 
Published: March 2020

Abstract
The purpose of this research was to describe the cognition processes of student with low functioning autism in solving mathematical problem. The subject in this research is a high school student with low functioning autism. Data was revealed through task-based interviews using instrument of mathematical problems. The cognition processes in solving mathematical problems involved understanding the problems, devising a plan, carrying out a plan, and checking to ensure the process of problem solving resulted in a correct answer. Some characteristics of autism was very perceptible during mathematical problems solving processes. The subject has difficulty in understanding the problem, even though the information in the problems is split into some simple information. The use of media provides assistance in an attempt to understand the problems even though it is not significant. The subject is unable to determine the plan of completion the problems because he has difficulty in understanding the problems. Subject provides answers that do not suitable with the question in a repetitive way. The subject speaks for itself during the process of understanding the problems.
Practical work design based on Science, Technology, Engineering, Mathematics (STEM) on manufacture of liquid sugar from cassava peel waste (Manihot esculenta) to improve student creativity
Authors: Muhardias D , Sunarya Y , Arifin M 
Published: March 2020

Abstract
The aim of this study is to create a practical work design based on science, technology, engineering and mathematics (STEM) on the manufacture of liquid sugar from cassava husks (Manihot esculenta) to improve the creative abilities of students. To achieve this, the question that arises in this study is “How can the characteristics of developing practical design based on science, technology, engineering and mathematics improve students’ creativity?" The researcher used Design-Based Research (DBR) method consisting of 4 phases: Problem identification and analysis, Designing a solution, Repeated cycles in testing and refining designs and Reflection to produce the principles of design and implementation. The Participants in this study were senior high school students, chemistry teacher and 3 observers who understood the STEM approach. Data was collected by interviewing, testing and observing the activities students. The results showed that student creativity increased through STEM-based practice.
How to analyze the students’ mathematization competencies in solving geometrical problems?
Authors: Suaebah E , Mardiyana M , Saputro D R S 
Published: March 2020

Abstract
Mathematization competency is considered in the field as the focus of the modeling process. This study aims to determine the extent to which the students mathematization competitions in solving geometrical problems. This research uses the descriptive qualitative method by using purposive sampling technique. The data in research are the result of contextual geometry problems and interview by the 8th graders of Junior High School in Surakarta. After that tested to five students can be concluded that students difficulties in horizontal and vertical mathematization. Students difficulties in horizontal mathematization refer to cannot transferring a real-world geometry problem to a mathematical model and difficulties vertical mathematization is adjusting, combining, refining and integrating models.
The effect of Double Loop Problem Solving (DLPS) on critical thinking skills and mathematical problem solving abilities
Authors: Muhammad M , Purwanto J 
Published: March 2020

Abstract
This research aimed to identify the effect of DLPS model on students’ critical thinking skills and mathematical problem-solving abilities. The variables involved in this research were thinking skills and mathematical problem-solving abilities as independent variables, and DLPS model as a dependent variable. One of the best learning strategies to encourage active thinking and problem-solving is the Double Loop Problem Solving (DLPS) model. DPLS model is a learning model of mathematical problem-solving approach that emphasizes students to find the main cause of the existence of a problem. This is in line with students’ mathematical problem-solving abilities that require the student to understand problems, plan or design problem-solving strategies, carry out calculations and verify the truth of the outcome or solution. The population of this study was the students at seventh grade in Junior High School State 1 Rembang, Purbalingga Regency, even semester in the school year 2017/2018. There was selected seventh grade of class B as experimental with 34 students and seventh grade of class E as control class with 34 students. The summary of the hypothesis testing, with the help of the SPSS program, is presented. Using Kolmogorov-Smirnov test for normality test and Levene’s test for equality of variances for homogeneity test, obtained significant value are 0.057; 0.145 and 0.168; 0.062 0.063; 0.681 and 0.244; 0.171 and 1.306; 2.359 more than alpha 0.05. It means that the students’ critical thinking skills and mathematical problem-solving abilities fulfilled assumption of normality test and homogeneity test. After conducting a series of normality and homogeneity tests, it was concluded that t-test for equality of means was used for hypothesis testing. The significant value is 0.019; 0.012 less than alpha 0.05. So that H0 is rejected, it means that students’ critical thinking skills and mathematical problem-solving ability taught by using DLPS model are better than students’ critical thinking skills and mathematical problem-solving ability taught by conventional learning. In other words, the DLPS model influences or effects on students’ critical thinking skills and mathematical problem-solving abilities.
Braking control strategies of modern hybrid and electric vehicles
Authors: Zaini Z 
Published: March 2020

Abstract
Environmental issues and oil resource depletion have urged government and car manufacturers to reduce production of combustion engine vehicle and at same time give more attention to hybrid and electric vehicle (HEV/EV). Fortunately, we have seen these future cars on the rood, for example, Nissan Leaf, Chevrolet Volt and Toyota Auris hybrid. To attract the buyers, these cars must have better efficient in term of equivalent litter per km. One way to achieve this goal, brake blending is incorporated to replace conventional brake system. This paper aims to investigate and compare the performance of such braking system using road test data. Recovered energy and driver comfort are two main aspect analyzed in aforementioned cars. Based on investigation detailed braking data on many driving conditions, it was found that different manufacturers employ different control strategies and have unique feature, respectively. Also, brake blending could cause driver confusion due to different pedal feeling experienced as in the combustion engine car.
5,10,15,20-tetraphenylporphyrin photoluminescence on nanoporous silicon substrates
Authors: Koroleva M O , Elistratova M A , Zakharova I B , Li G V , Sreseli O M 
Published: March 2020

Abstract
Photoluminescence of 5,10,15,20-tetraphenylporphyrin (H2TPP) on nanoporous silicon substrates has been studied. Used nanoporous silicon has a visible PL in the region of H2TPP absorption. Reradiation of porous silicon photoluminescence to the tetraphenylporphyrin long-wavelength peak of the photoluminescence spectrum is observed. The substrate microrelief plays a major role in the formation of tetraphenylporphyrin crystalline structures. The microrelief size of porous silicon was controlled by changing the technological parameters of electrochemical etching.
Photovoltage measurement by modulated photoemission on the p-GaAs surface with cesium overlayers
Authors: Khoroshilov V S , Protopopov D E , Kazantsev D M , Zhuravlev A G 
Published: March 2020

Abstract
A contactless two-beam modulated photoemission technique for measuring the photovoltage on the surface of highly doped semiconductors is proposed and verified for the p+-GaAs surface with adsorbed Cs. The surface photovoltage evolution under the Cs deposition on the highly doped p+-GaAs surface is compared with that observed on Cs/UP+-structures by the photoreflectance spectroscopy method. The pump intensity dependence of the photovoltage is measured. This allows us to determine the absolute photovoltage values.
Terahertz luminescence and photoconductivity associated with the impurity electron transitions in GaAs/AlGaAs quantum wells
Authors: Kurnosova A D , Makhov I S , Firsov D A 
Published: March 2020

Abstract
The photoconductivity and photoluminescence spectra of GaAs/AlGaAs quantum wells doped with shallow donors are studied at low lattice temperatures. The optical electron transitions between the first electron subband and donor ground states, as well as between the excited and ground donor states, are revealed in the terahertz photoluminescence and photoconductivity spectra. The temperature evolution of the impurity-related photocurrent in the terahertz spectral range is also studied.
Difference in the behavior of the photon echo of excitons in InGaAs/GaAs quantum wells from the predictions of the model of two-level system ensemble
Authors: Yanibekov I I , Solovev I A , Eliseev S A , Efimov Yu P , Lovcjus V A , Kapitonov Yu V 
Published: March 2020

Abstract
In this work, we studied the photon echo from heavy-hole excitons in a thin InGaAs/GaAs quantum well. To analyze the results, we used the model of an ensemble of two-level systems. The model allows us to describe the temporal profile and the moment of arrival of the echo signal, as well as the echo amplitude decay with increasing delay between pulses. In addition, excitation-induced dephasing effect was observed, that was beyond the limits of applicability of the model.
Variable-temperature luminescence studies of InAsSb-based LED heterostructures emitting beyond 5 μm
Authors: Semakova A A , Romanov V V , Moiseev K D , Bazhenov N L , Mynbaev K D 
Published: March 2020

Abstract
Variable-temperature (4.2 - 300 K) electroluminescence (EL) studies were performed on two asymmetrical InAs/InAsSb/InAsSbP LED heterostructures emitting at 5.02 and 5.10 μm wavelengths at 300 K (with an InSb content in the active layer of 0.15 and 0.16, respectively). For the structure with the narrowest bandgap, a weak temperature dependence of the position of the EL peak was observed. Along with strong carrier localization in the active layer, which was provided by the design of the structure, this made the studied heterostructures promising for fabrication of LEDs with working wavelengths extending beyond 5 μm at 300 K.
Acceptor-related terahertz and infrared photoconductivity in p-type GaAs/AlGaAs quantum wells
Authors: Vinnichenko M Ya , Makhov I S , Panevin V Yu , Kharin N Yu , Vorobjev L E , Sorokin S V , Sedova I V , Firsov D A 
Published: March 2020

Abstract
Photoconductivity in GaAs/AlGaAs quantum well nanostructures doped with acceptors was studied at low lattice temperatures in the infrared and terahertz spectral ranges. The photocurrent spectra revealed features that can be attributed to the hole transitions from the ground acceptor state to the excited acceptor states and size-quantized subbands.
Synthesis and characterization of GaPN/GaP heterostructures grown on silicon (001)
Authors: Koval O Yu , Sapunov G A , Fedorov V V 
Published: March 2020

AbstractIII-V compound semiconductor heterostructures grown on Si wafers are one of the promising materials in modern optoelectronics. The most promising candidate providing lattice matching with Si is III-phosphide-based alloys diluted with nitrogen. In this work, we study the effect of growth conditions on the structure and optical properties of GaP1−xNx/GaP/Si planar heterostructures synthesized by plasma assisted molecular beam epitaxy. A series of samples with a maximum impurity nitrogen content as high as 5.05% was synthesized. The morphological, structural and optical properties of heterostructures are studied with scanning electron microscopy and optical spectroscopy. All of the samples demonstrate a broad photoluminescence (PL) response in the red wavelength region at room temperature (RT). The most efficient RT PL is obtained with the samples grown under a high nitrogen gas flow through a nitrogen plasma cell.
GaAs diode structures with n+-p junction on Ge/Si templates
Authors: Rykov A V , Denisov S A , Shengurov V G , Baidus N V , Buzynin Yu N 
Published: March 2020

Abstract
GaAs layers were grown by metalorganic epitaxy on Ge/Si(001) substrates, which were formed by chemical vapor deposition with decomposition of GeH4 on a hot wire. High structural quality of thin Ge layers (0.2 - 0.3 μm) on a silicon substrate made it possible to grow high-quality GaAs layers. The resulting n+-GaAs/p-GaAs/p-Ge/p+-Si diode structures demonstrate low reverse currents.
Temperature activation of indirect exciton in nanostructures based on MoS2
Authors: Smirnova O O , Eliseyev I A , Rodina A V , Shubina T V 
Published: March 2020

Abstract
Micro-photoluminescence studies of MoS2 nanotubes have shown that both direct and indirect excitonic transitions contribute to the emission spectra despite the fact that dozens of monolayers are inside their walls and, therefore, only indirect exciton emission would be expected. In addition, the intensity of the indirect exciton band increases with temperature in contrast to the direct exciton band, the intensity of which decreases. The same effects are observed for MoS2 flakes. To describe these phenomena, we propose a theoretical model that considers the balance between exciton transitions taking into account the spin-forbidden exciton states.
Viability of encapsulated Lactobacillus casei using glucomannan iles-iles and skim milk to low pH and bile salts
Authors: Ngatirah  
Published: March 2020

Abstract
The aim of this study was to determine the effect of glucomannan iles-iles concentration as an encapsulating agent and skim milk concentration as the protectant agent on the viability of L. casei in the encapsulation process using spray drying, and to determine its viability in low pH and bile salts. The experiment used a randomized complete block design with two factors. The first factor was the concentration of glucomannan in three levels, A1 (5%), A2 (10%), A3 (15%). The second factor was the concentration of skim milk as a protectant agent with three levels, B1 (9%), B2 (12%) and B3 (15%). The concentration of glucomannan iles-iles and skim milk had no significant effect on the cell number of L. casei. Based on the number of L. casei after the spray drying process. Decrease in viability L. casei after spray drying and stored for 3 months, about 2 log cycles. The highest viability of encapsulated L. casei cells against low pH and bile salts was obtained at 5% glucomannan concentration and 9% skim milk.
Pigments extraction from monascus-fermented durian seed
Authors: Srianta I , Ristiarini S , Nugerahani I 
Published: March 2020

Abstract
Durian seed has been studied as a new substrate for Monascus solid state fermentation. Monascuspurpureus produce yellow, orange and red pigments during the fermentation. The purposes of this research were to study the pigment extraction from the Monascus-fermented durian seed (MFDS) by using ethanol and water at various ratios and to analyze the pigment composition of the extracted pigment. The extraction was conducted in a 250 mL Erlenmeyer with 1 g of powdered MFDS and 50 mL of solvent at various ethanol:water ratios (10:0; 9:1; 8:2; 7:3; 6:4 and 5:5), in a shaking waterbath at different temperature (30°C and 60°C), 100 rpm agitation for 2 hours. The extracts were subjected to pigment content analysis by using a spectrophotometer and thin layer chromatography (TLC). Extract with the highest pigment content was then subjected to pigment compounds detection by using liquid chromatography-mass spectrometry (LC-MS). The results showed that extraction at 30°C was more effective than that at 60°C. The lower the ethanol:water ratio until 7:3, the higher the pigment content extracted. However, the lower the ratio tends to lower pigment content. Interestingly, the lower ethanol:water ratio, more viscous extract resulted. The TLC analysis showed that the extracts contained various pigments. Consistent with those results of TLC, various pigment compounds detected by LC-MS.
Physico-chemical and antimicrobial properties of caseinchitosan edible films as food quality and food safety
Authors: Apriliyani M W , Purwadi  , Manab A , Ahmad B M , Uula L M 
Published: March 2020

Abstract
Edible films can be useful in extending product shelf life and the surrounding environment to enhance the quality of food products protecting from physical, chemical, biological deterioration. Casein and chitosan are natural materials for producing edible films. These films are also able to incorporate as barriers to water vapor, oxygen and carbon dioxide and as carrier substances to inhibit pathogenic and spoilage microorganisms. Observations were conducted to the formulations of the casein and chitosan solution ratio 1:1; 1:2; 1:3 and 1:4 (ml:ml) in order to determine one that yields the best solution. The objectives of this study was to characterize physicochemical (water vapor permeability, water activity, and film solubility) and antimicrobial properties of casein-chitosan (Staphylococcus aureus, Lactobacillus bulgaricus, Escherichia coli, and Salmonella sp.). The effect of the casein-chitosan on edible films was monitored. The best solution on casein:chitosan ratio = 1:4 (ml:ml). The greatest water vapor permeability with 0.1140 g.mm/m2.h.kPa, film solubility with 32.809% and water activity with 0.709. Antimicrobial activity of edible films casein-chitosan against Staphylococcus aureus, E.coli, Salmonella sp. and Lactobacillus bulgaricus was ratio solution dependent.
Powder production of sea cucumber (Holothuria scabra): effect of processing methods on the antioxidant activities and physico-chemical characteristics
Authors: Ansharullah  , Tamrin  , Patadjai A B , Asranuddin  
Published: March 2020

Abstract
Sea cucumber is a fishery commodity in Southeast Sulawesi that has high economic value and has long been used as traditional natural medicine. One of the active ingredients contained in sea cucumbers is antioxidants. The purpose of this study was to characterize the antioxidant activity of sea cucumber (Holothuria scabra), which were processed into powder with various processing methods. The processing methods used were smoking, steaming and microwaving. The powder were then measured its antioxidant activity using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method. Other characteristics tested were their chemical content and morphological properties with Scanning Electron Microscope (SEM). The results showed that the sea cucumber powder production with the microwaving method produced a powder that had stronger antioxidant properties compared to smoking and steaming methods. The sea cucumber powder produced with microwave method had a higher protein content, and its morphological appearance indicated more physical damage. The method of sea cucumber powder preparation with microwave appeared to be likely more efficient in time and would have a better nutritional value.
The effect of ozonation on dissolved oxygen and microbiological content in refill drinking water
Authors: Sofia D R 
Published: March 2020

Abstract
One indicator of safe drinking water is its microbiological content of 0 colonies/100 ml. Ozonation is one method for killing microbes contained in drinking water. Disinfection in refillable drinking water that uses ozone needs to be studied, considering that the drinking water put into used gallons is washed again and can be drunk directly by consumers. It should be suspected that the drinking water used from drinking refill water contains bacteria, a dangerous virus. So the purpose of this study is to find out the microbiological content in refill drinking water with variable storage time for refill drinking water. The research method used is an observational research method. The parameters observed were temperature, pH, total microbes and dissolved oxygen content where the dissolved oxygen content indirectly indicates the reaction process of ozonation and bacterial activity contained in refill drinking water. The results showed that at pH showed a decrease from day to day, things this is caused by chemical reactions and microbiological activities. TPC shows that the smallest TPC value is 1 colony/100 ml on the second day, this is due to the ozone reaction in the water here H2O2 and (OH *) are very strong oxidizers which work optimally on the second day and then increase to 13 colonies/100 ml on day 5. The result of DO examination was an increase in DO on the second day to 8.2 mg/l which afterward finally decreased again the following day, this was due to an ozone reaction and bacterial activity in the water, therefore it was recommended that storage of drinking water after ozonation be stored for 2 days, and need renewal in the cleaning and disinfection of gallons to be used.
Effect of α-amylase digestion in fermented Nagara bean grits for gelatinization profile and in vitro starch digestibility
Authors: Susi  , Agustina L , Gendrosari S 
Published: March 2020

Abstract
Treatment of α-amylase digestion in wet grits nagara bean after spontaneous fermentation was assessed to determine changes in rehydration ability, gelatinization profile and in vitro starch digestibility of the flour produced. This was important for further processed products that required easy hydration in cold water and high starch digestibility. The research was carried out by hydrolysis of α-amylase with 60 IU enzyme activity as much as 0.1% on wet grits nagara beans from spontaneous fermentation which had been soaked in NaHSO3 and Ca(OH)2 for 1 hour. Moreover, α-amylase digestion was carried out at 37°C for 30, 60 and 90 minutes. The results showed that the amylose content of nagara bean flour from the pre-treatment soaking using Ca(OH)2 was relatively higher than the pre-treatment of NaHSO3, and there was a tendency for amylase digestion up to 90 minutes could reduce amylose and starch content. In vitro starch digestibility of flour by amylase digestion of wet grits nagara bean for 60 minutes with pre-treatment soaked in Ca(OH)2 were 88.79% db, peak viscosity and final viscosity of 2416 cP and 2419 cP respectively.