bluuebunny/crossref_metadata_2025 huggingface dataset:
Cosmic Evolution of Nearby Radio Active Galactic Nuclei
Authors: Andika Irham Taufik , Arifyanto Mochamad Ikbal , Istiqomah Ade Nur , Amalina Shinta Nur , Aprilia  , Hakim Muhamad Irfan
Published: June 2019

The exact formation mechanism of massive galaxy in the universe still become an open question in modern astrophysics. Radio emission from active galactic nucleus (AGN) is known to be suppressing stellar growth in the most massive galaxies, thus becoming significant ingredient in modeling galaxy formation process. Radio luminosity function across cosmic redshifts (z) is an important tool to constrain the co-evolutionary models of radio AGN and its host galaxy. Therefore, we aim to calculate radio luminosity function at 1.4 GHz frequency for radio AGN in the range of 0.1 ≤ z ≤ 1.3 in this work. The radio data was taken from deep VLA observation of Stripe 82 field at angular resolution of 1.8” and 52 μJy sensitivity. On the other hand, the optical/near-infrared data was taken from Dark Energy Survey DR1 observation in g, r, i, z, Y bands with co-added catalog limiting magnitude of i = 23.44.

We estimated the photometric redshift (photo-z) of each sources by using combined two machine learning algorithms: neural networks and boosted regression trees. We successfully performed accurate photo-z measurement with average bias 〈δ〉 = −3.5 × 10−3, scatter 〈σ〉 = 0.15 and outlier fraction 〈f(3σ)〉 = 0.06. By using 1/V
max method, we calculated the luminosity function, then constrained their evolution with pure density evolution (PDE) or pure luminosity evolution (PLE) model. At median z = {0.31, 0.59, 0.88, 1.10}, we found the power-law index of PDE is αD
= {1.29, 1.43, 1.73, 0.94} while for PLE is αL
= {2.28, 2.59, 3.19, 1.63}. Our result is consistent with previous studies and gives better constraint to radio AGN luminosity and density evolution power-law indexes due to larger number of sources (6900) and wider covered sky fraction (92 deg2).
Diffuse Interstellar Bands in the High-Resolution GAOES Data
Authors: Puspitarini L , Malasan H L , Hashimoto O
Published: June 2019

Diffuse interstellar bands (DIBs) are an enigmatic set of interstellar absorption features, observed at optical and near infrared wavelengths in the spectra of reddened stars in our Galaxy also in other galaxies. Identifying the carriers of DIBs has been a longstanding challenge and is still very much a work in progress. In recent years, surveys of DIBs have been conducted, but mostly focus on strong bands. In this work, we extracted and measured DIBs recorded in the high-resolution stellar spectra of ε Auriga (ε Aur) and IQ Per observed by using Gunma Astronomical Observatory Echelle Spectrograph (GAOES) (spectral resolution R∼65000). Observations were aimed at obtaining high resolution spectra of double-lined detached eclipsing binaries. For each selected DIB, we performed spectral fitting of a combination of a smooth stellar continuum (polynomial function), an empirical DIB model, and a synthetic telluric transmission. The high-quality data allow us to measure not only strong and well-known DIBs, but also weaker DIBs.
Introducing the Zwicky Transient Facility and the Be star variability program: a progress report at the National Central University
Authors: Ngeow C-C , Lee C-D , Yu P-C , Masci F , Laher R , Kupfer T , Golkhou V Z
Published: June 2019

The Zwicky Transient Facility (ZTF) is a modern-day wide-field optical survey to systematically explore the transient and variable sky. The ZTF utilizes the 48-inch Samuel Oschin Schmidt Telescope located at the Palomar Observatory. This telescope is equipped with a mosaic CCD camera that provides a field of view of 47 squared degrees. The allocated observing time of ZTF can be divided into partnership time (40%), public time (40%) and Caltech time (20%). The public time contains two surveys: a 3-day cadence for the Northern Sky Survey and a 1-day cadence for the Galactic Plane Survey. Astronomical communities in South East Asian countries are encouraged to explore the public ZTF data once it is released in March 2019. Taiwan’s National Central University (NCU) is one of the partnered institutions, and a major ZTF-related project carried out at NCU is the ZTF Be stars variability (ZTF-BeV) program. The main goal of our program is to study the variability of Be stars in the range of ∼13.5 to ∼20.5 magnitudes.
Identification warp and flare milky way’s disk in the third galactic quadrant
Authors: Hidayat W , Arifyanto M I , Aprilia  , Hakim M I
Published: June 2019

Milky Way’s disk has a feature called warp and flare. Warp is a bending phenomenon of the galactic disk. This feature is noticeable in the first and third galactic quadrant. Meanwhile, flare define as the increment of galactic disk scale high depends on galactocentric distance. Galactic disk tracers (dust, gaseous, and stars) can be used to explain the presence of both structures. The reddening of 10 young open clusters (OC) and 2985 early-type (OB) stars chosen in this work. Both components predicted to represent the galactic disk component where the warp and flare occurred. The Milky Way Star Cluster (MWSC) catalogue used to select the open clusters initial parameters. Then, we used proper motion data from GAIA DR2 combined with photometric data from Two Micron All Sky Survey (2MASS) catalogue to determine the open cluster membership and reddening. The open cluster memberships are selected using scatter algorithm. Then, the JHKs photometric data used to build the Two Colour Diagram (TCD) and Colour-Magnitude Diagram (CMD). We selected the reddening of OB stars data from Tycho 2 catalogue. The result is an increment of colour excess depends on galactocentric distance. This distribution could indicate the presence of warp and flare of the Milky Way’s disk.
Relationship among Self-Motivation, Self-Efficacy and Achievement of High School Student in Biology
Authors: Nurwendah Wenty , Suyanto Slamet
Published: June 2019

This research aims to reveal: (1) the relationship among self-motivation and self-efficacy of high school student in biology (2) the relationship among self-efficacy and achievement of high school student in biology (3) the relationship among self-motivation and self-efficacy of high school student in biology, and (4) the relationship among self-motivation and self-efficacy and achievement of highs school student in biology. This research was a quantitative descriptive research, using a survey method. The instrument used a questionnaire for collecting the data. The population was all of grade XI students of natural science class of high schools in Yogyakarta City. The sample was by using the quota sampling technique. The data were analyzed by using the linear regression, Pearson correlation coefficient, and multiple regression analysis. The criteria for determination was at the significance level of 0.05.
A Meta Analysis on Biology Worksheet’ Students Forms
Authors: Windari Tri , Gusti Suryadharma I
Published: June 2019

This study was aimed to analyze LKPD (students’ worksheet) in Biology subjects. The LKPD (students’ worksheet) is a collection of sheets containing the activities of students that allow students to carry out real activities with objects and problems learned. The LKPD (students’ worksheet) is used by teachers in facilitating students and must be oriented to the scientific process to find or prove the concept. This research method is a meta-analysis. Data collection techniques were by searching for electronic journals on Google and Google scholars. The population of this study is the level of secondary education, especially high school. The sample is LKPD (students’ worksheet) of Biology subjects. Based on the meta-analysis, the results of this study are the LKPD (students’ worksheet) in Biology subjects can be grouped according to their form, namely LKPD which helps students find concepts, LKPD which helps students apply and integrate concepts, LKPD as a learning guide, LKPD as reinforcement, LKPD as practical guide. The LKPD (students’ worksheet) classification including conventional LKPD (students’ worksheet), approach based LKPD (students’ worksheet), learning model based LKPD (students’ worksheet), character education based LKPD (students’ worksheet), thinking skills based LKPD (students’ worksheet), problem based LKPD (students’ worksheet), and technology based LKPD (students’ worksheet). The form of LKPD (students’ worksheet) finding the highest concept of 39% and the highest frequency is conventional LKPD (students’ worksheet) of 12.
Exploring Guided Discovery Learning: The Effect on Students’ Integrated Ability and Self-Regulated in Chemistry
Authors: Permatasari Dea , Laksono E. W.
Published: June 2019

The purpose of this study was to investigate the effect of a guided discovery learning (GDL) toward students’ integrated ability and self-regulated. The study was post-test only control group research design and the participants consisted of students in senior high school (N = 65). The topic of buffer solution was selected both the experimental class and control class, whereas the experiment class used GDL approach and control class used expository learning (EL). The ‘Integrated Assessment’ and ‘Self-Regulated Questionnaire Form’ were used as data collection tools in the research. Results of the descriptive analysis of post-test showed that the frequency of answers was the higher category for the experimental class than the control class students. In addition, results of the MANOVA test indicated that post-test scores were students in GDL class had significantly higher total integrated ability and self-regulated scores over their traditional counterparts. In this research, it was concluded that the GDL used in relation to the topic of buffer solution had significant effect toward students’ integrated ability.
Development of Android Comic Media for the Chapter of Newton’s Gravity to Map Learning Motivation of Students
Authors: Nikmah Syafridatun , Haroky Faruq , Jumadi  , Wilujeng Insih , Kuswanto Heru
Published: June 2019

This research was designed to map students’s learning motivation by developing comic physics media. This study used the ADDIE development model. The subjects tried in this study were students in one senior high school in Yogyakarta at the grade of 10th science. Data collection instruments were in the form of students’ motivation observation sheets and students’ learning motivation questionnaire. The data obtained were analyzed quantitatively. The results showed that (1) Android-based physics comic media on the Newton’s Gravity chapter was an innovation in the world of education that utilized TPACK (Technological Pedagogical Content Knowledge). (2) Comic media can be and are suitable for use in physics learning for senior high school, and (3) comic media can be used to map the learning motivation of high school students.
Experimental and Numerical Study of Co-firing Peat with Syngas in a Vortex Burner
Authors: Evdokimov O A , Mikhailov A S , Guryanov A I , Piralishvili Sh A , Veretennikov S V
Published: June 2019

Experimental and numerical study of co-firing peat with different gaseous fuels in the vortex burner are carried out. At the “lean” operational regimes co-firing peat with syngas is more effective and allows to organize reliable ignition and stable combustion at the values of excess air coefficient up to αΣ = 2.7. In addition, co-firing with syngas requires less initial methane to produce it applying catalytic reforming than direct co-firing with methane. Also, syngas supply into vortex burner allows to reduce combustion temperature and emission of NOx.
Mathematical modeling of burn-out of the coal particle coke residue
Authors: Salomatov Vl , Salomatov Vas
Published: June 2019

Combustion of solid fuels in general includes a number of stages: heating, drying, devolatilization, ignition, and burn-out of coke. The stage of coke residue burn-out is the leading one. In this paper, analytical solutions for the burn-out of the coke part of an anthracite particle were developed using the asymptotic procedures, and combustion of anthracite particles with the size of 100 µm and less (presented size for the flare process) and 12 mm or more (characteristic size for burning in a fluidized bed) was calculated. In the first case, combustion occurs in the kinetic regime, and in the second, it occurs in the diffusion regime. The models of the “hard” ash frame, as well as the model “with segregating” ash, have been implemented.
Subsurface analysis of 6082-T6 Aluminium alloy’s mechanical properties subjected to small particles erosion
Authors: Erdoğan A A , Țarcă I C , Rus A , Țarcă R C
Published: June 2019

6082-T6 aluminium alloy is a ductile metal. When subjected to small particles erosion, sub-surface deformations are expected due to the particle impact. Plasticity is one of the properties which might reveal the rate of the deformations. As a result of plastic deformation, mechanical properties of the samples are expected to change with distance from the surface. Typically, the depth of the plastically deformed region could be between 5 and 200 μm. In order to understand the plasticity of the materials, nanoindentation researches were conducted. Aluminium alloy samples were previously subjected to hard material particles jets (Al2O3) under different values of incident angle, between 15 and 90 degrees. After a 3D scan of the resulted surfaces, the samples were cut in such a manner that the middle section remained visible and prepared for nanoindentation analysis. The paper presents the experiments conducted as well as some of the achieved results.
Additivation of vegetal oils for improving tribological characteristics
Authors: Georgescu C , Solea L C , Deleanu L
Published: June 2019

This paper presents a review on issues on additivating vegetal oils with friction and anti-wear modifiers. A SWOT analysis on vegetal oils reveals the shortcomings of these oils and the trend in their modification by the help of additives. Based on research reports available from literature and their experimental work, the authors formulated a synthesis on how the friction and wear modifiers act in lubricants and especially in vegetal oils. They discussed the influence of some friction and anti-wear modifiers added in vegetal oils, especially in soybean oil and rapeseed oil. The conclusion is that additivation of vegetal oils is still at the beginning as the reported results are not so efficient as compared to aditivation of classical alternative -mineral oils and even less as compared to synthetic oils. But research must be continued as these vegetal oils become an actual resource for lubricants base-stock.
Geometry influence on silent chain – sprocket friction
Authors: Jurj L , Velicu R , Lates M T
Published: June 2019

The silent chains in theory should not present friction at the level of the plate entering in contact with the sprocket, based on the literature. Experimental results have shown that there is a certain amount of friction, which can be inspected even visually. This scientific paper presents a geometric simulation using the exact geometry of the plate and the sprocket, to calculate the amount of mechanical work lost by friction at the entering of the plate in contact with the sprocket teeth. This modelling considers the different deviations of the pitch of the chain, resulted from nominal tolerances, elastic elongation and wear.
Virtual keyboard based on a brain-computer interface
Authors: Rusanu O A , Cristea L , Luculescu M C , Cotfas P A , Cotfas D T
Published: June 2019

This paper proposes a novel LabVIEW based algorithm regarding the implementation of an eye-blinks strength controlled virtual keyboard aimed to help people with neuromotor disabilities. The application can be considered a brain-computer interface which is useful for the assistance of patients suffering from Locked-In syndrome or amyotrophic lateral sclerosis. A precise, repeatable and easily detectable control signal could be the eye-blink strength. The LabVIEW based virtual keyboard provides the following features: detection and counting the voluntary eye-blinks, switch command, select command, highlight action running in parallel with the previously mentioned processes, enabling cancel, delete and space commands. The working principle underlying the implementation of the proposed virtual keyboard is Divide and Conquer paradigm. Thus, it is possible the switching task across the rows, half rows and keys (characters) in order to select a row, half row, respectively key associated to the character that should be introduced in the text box.
Classification of industrial robots according to the number of degrees of mobility-structural synthesis and useful configurations
Authors: Staretu I
Published: June 2019

Industrial serial robots can be classified according to several criteria, the most important being: the number of mobility degrees or independent movements, the number of independent kinematic axes, the shape of the workspace, the value of the useful load, the precision of touching a predetermined point, etc. Among these criteria, the number of degrees of mobility directly determines the structure of the kinematic chain corresponding to the robot and implicitly its construction, functionality and utility. In this paper, we define the three classes of industrial serial robots according to the degree of mobility: the class of industrial serial robots of minimum configuration, the class of redundant industrial serial robots and the class of hyper-redundant industrial serial robots. For each class of industrial serial robots the structural synthesis method is presented and representative examples of structures are given.
A survey on gear meshing quality based on tooth contact analysis
Authors: Radu M C , Andrei L , Andrei G
Published: June 2019

Gears are common mechanical elements in power transmission systems. In order to avoid failure of transmission systems, it is necessary to inspect the gear meshing condition with respect to kinematic and dynamic parameters. Tooth contact analysis (TCA) method represents a useful tool for designing and analysing gear performance. It represents an important method to examine gear tooth contact points, contact ratios and kinematic errors. The primary objective of TCA is to establish the contact trail on gear tooth surfaces, and also to determine the transmission error functions generated by gear misalignments. TCA has several branches such as the loaded tooth contact analysis, unloaded tooth contact analysis and tooth contact analysis with errors. The determination of the initial contact point is necessary in order to achieve an accurate solution. The present survey allows a new insight into the improvement of the gear meshing quality, based on tooth contact analysis and transmission error.
The effect of urban buildings on the implementation of small wind turbines
Authors: Ciobanu D , Gheorghe M , Saulescu R , Midoi B , Jaliu C
Published: June 2019

The paper presents the main factors that can influence the location of a wind turbine (building shape, construction height, direction and wind speed) aiming to increase its performance. Thus, three types of buildings with various shapes and heights, which can be found in the urban environment (houses, offices and hotels) are presented in a case study, numerical simulations being carried out using the ANSYS software. The aerodynamic tunnel is customized for each building while maintaining a proportion of the building and the space needed to analyse it. All buildings are rotated to the wind direction and not to the theoretical North. The objective of this paper is to identify the area of the building in which an increase of the airflow is obtained, which allows to increase the performances of the wind turbine. The results allow formulating recommendations for the implementation location and types of units that should be installed.
Study behavior of Geneva mechanism using 3D printing technology
Authors: Rizescu D , Besnea D , Rizescu C I , Moraru E
Published: June 2019

The authors developed a study for behaviour of Geneva mechanism considering different materials and technologies. Generally, there are three basic types of Geneva motion mechanisms named external, internal and spherical. In this paper the authors considered external Geneva mechanism. The design and machining of a conventional Geneva mechanism are generally well known, but there are some particularities, if we consider 3D printing technologies. Conventional, Geneva mechanisms are used to low-speed applications, or to those in which noise and vibration are of no importance. Using PLA+Copper or ABS materials noise and vibrations are reduced considerably. Also, the entire mechanism has a reduced weight. There were considered different fill factors for 3D printed parts. The experimental setup allows fast changing of mechanism parts. This research aims the study of behaviour of 3D Printed machine elements like: springs, bearings, clutches gears, bellows, diaphragms, bushes, brakes, sliders, etc developed by authors.
Research concerning the achievement of eco-innovation virtual hub tools to increase Romanian economic environment competitiveness
Authors: Radulescu I
Published: June 2019

The paper presents the virtual hub experimental model achievement consisting of an innovative tools series in order to facilitate innovation, knowledge transfer and waste recycling efficiency of electrical and electronic equipment.

The Hub includes a tools set to increase recycling efficiency: the passport for electrical and electronic products recycling, the multi-criteria analysis method for the product, pointing relevant features for recycling, the implementation model of eco-innovative technologies at company level, the recyclability evaluation method based on idealism. It also includes an eco-innovation library, an eco-innovation and training laboratory, a Forum, as well as User Guides for each tool and a cost-benefit analysis guide for e-waste recycling.

The obtained tools, in their form, are an absolute novelty in the field of WEEE recycling and they address a new way of thinking and a new philosophy about material recovery and recycling and resource economy.
The components and vectors of excellence
Authors: Puiu C , Puiu V
Published: June 2019

This work aims at identifying the components of excellence (market, products / service, development) through a new contextual approach. An interdisciplinary scientific instrumentation is utilized, by placing, into the space of the vector theory in physics, the economical sizes that, by summing, can provide a real quantification (concrete, precise) of the excellence in business. The work proposes a new quantification modality of the excellence level through the method of vectorial composition, taken over from physics (mechanics). After the components of excellence (market, product / service, development) have been established and represented as vectors, the calculation of the resulting vector (excellence) can be done, through the classical vectorial composition, into a system of axes, determined by the excellence components.
Assisted quality inspection for hip prostheses components
Authors: Braun B C
Published: June 2019

In the paper is presented a new method for quality analysis of some hip prosthetic elements, surface quality standpoint. First of all it is about the head, as spherical joint for the hip prosthesis. For best bio-compatibility is absolutely necessary that its surface to be well processed standpoint roughness, for lowest friction forces, as much as possible those in the case of the natural hip joint. For this reason, within our current research activities, we have developed a virtual instrument, as software interface for efficient assisted roughness deviations for spherical joints of the hip prostheses, reported to a reference hip prosthesis. This application could be very practical and useful for the stage of adjustment and grinding prostheses heads, increasing the productivity and reducing the number of scraps cases in production
Method to model the spinal column shape
Authors: Vutan A M , Gruescu C M , Lovasz E C , Ciupe V
Published: June 2019

Correct evaluation of the spine is important in detecting the deficiencies that may occur at this level, especially in case of scoliosis. It is proposed a new method of acquiring the coordinates of the column in order to generate a model of it. A number of eight coordinates has been chosen to use, a big enough number to assure a true model of the spine and a wide area of possible mathematical approaches. The acquiring system consists of eight accelerometers, from which is collected the pitch angle. This angle, as the angle of inclination in the frontal plan is used to compute the pairs (x, y), considering known the distance between the sensors. The accuracy of the model is validated by comparison with images taken during the measurement.
Printed Low-Cost Microfluidic Paper-based Analytical Devices for Quantitative Detection of Vitamin C in Fruits
Authors: Andini  , Andayani Ulfa , Anneke  , Sari Meiria Istiana , Sabarudin Akhmad
Published: June 2019

Microfluidic paper-based analytical device has been fabricated and subsequently applied to determine the Vitamin C level of the non-seasonal fruit i.e pineapples, oranges, guavas, and apples in Indonesia. µPAD was prepared by creating a hydrophobic barrier on Whatman Chromatography paper No. 1 in a certain pattern printed using Xerox Colorcube 8580 DN-2. 0.05 µl of 2,6-Dichlorophenolindophenol was dispersed into a detection area on the µPAD devices prior to the addition of 0.2 µl of fruits juice samples. The barrier allowed the fruits juice to flow and alter the color of the reagents through a redox reaction. Vitamin C in fruit juice altered the color of 2.6-Dichlorophenolindophenol reagent into a pinkish color. The changing of the reagent color was then processed using Image J software to determine the RGB intensity level. The results showed that the average amounts of Vitamin C in pineapples, oranges, guavas, and apples are 0.05%, 0.05%, 0.08%, and 0.04% respectively.
Comparing between mGCV and aGCV Methods to Choose The Optimal Knot Points in Semiparametric Regression with Spline Truncated Using Longitudinal Data
Authors: Damaliana Aviolla Terza , Nyoman Budiantara I , Ratnasari Vita
Published: June 2019

Semiparametric regression is a combination of parametric and nonparametric components. The estimation of the semiparametric regression function uses a parametric approach and a nonparametric approach. This study uses longitudinal data. The estimation technique in this study uses Spline truncated which has very special, excellent statistical interpretation and visual interpretation. The estimation technique in longitudinal semiparametric regression uses the weighted least square (WLS). The choice of knots in semiparametric spline truncated regression is very important because the number of knot points and locations of each knot will affect the regression estimation form. The method of selecting knots in this study uses a Modification of Generalized Cross-Validation (mGCV) and aGCV. This study uses cases of life expectancy in East Java Province 2001-2015. Comparison of the two methods based on the R-square value and the value of Mean Square Error (MSE). The results show that the R-square value of mGCV is greater than aGCV and the MSE value of mGCV is smaller than aGCV. So, it can be concluded that the mGCV method is better than the aGCV method for optimal selection of knot points in the case of life expectancy in East Java Province.
Fuzzy Logic Application as A Tool for Classifying Water Quality Status in Gajahwong River, Yogyakarta, Indonesia
Authors: Dewanti Novita Ayu , Abadi Agus Maman
Published: June 2019

The growth of manufacturing and waste disposal in the Gajahwong River watershed has resulted in decreasing river water quality. Therefore this study aims to develop a fuzzy logic system in classifying water quality status in Gajahwong River. There are 11 parameters used for classifying water quality status, namely temperature, potential hydrogen (pH), dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), free chlorine, nitrate, nitrite, oil and fat, lead and Escherichia coli (E. Coli). These parameters are used to assess the Gajahwong River water quality at three different stations during the period of 2007 to 2017. The application process of fuzzy logic begins with the use of 11 parameters consisting of physical, chemical and biological parameters as input, with the Mamdani method as the fuzzy inference system. The output of this application is in the form of water quality status which is categorized as normal (N), lightly polluted (LP), moderately polluted (MP) and heavily polluted (HP). The classification is expected to facilitate the public in reading information about the quality of river water from the environmental agencies D.I. Yogyakarta, thus, the public can be aware of maintaining watersheds.
Acquisition of Voltage and Current Signals using A Single Board Computer for Online Monitoring of Powers
Authors: Dharmawan Hari Arief , Wardoyo Arinto Yudi P. , Widodo Chomsin S.
Published: June 2019

During this time, Single Board Computers (SBCs) are widely used in monitoring and control applications. Many relatively low-cost SBCs are available. This paper explains the implementation of an SBC LattePanda for online monitoring of powers through Local Area Networks (LANs). The SBC was used as the main part of the monitoring system that mainly performed acquisition of voltage and current signals sent by some sensors. A program for the microcontroller on the SBC was written for the acquisition processes. Furthermore, a client/server application was developed using Delphi to perform online monitoring of the signals. Some experimentation was performed to mainly ensure that the microcontroller could capture the voltage and current signals with precise and constant sampling timing as well as send the data to the client/server application successfully. A PicoScope was utilized during the experimentation to gain the timing information performed by the microcontroller. For calibration of the voltage and current, a 4.5-digit digital multimeter was implemented. The final stage of the experimentation revealed that the intended signals could be sampled with a constant timing and in this case 128 samples per channel was chosen. The developed application could also show the expected parameters including the signal of powers using an additional remote computers connected to the LAN.
Theoretical study on the corrosion inhibition performance of dibenzo-18-crown-6 and its derivatives
Authors: Hadisaputra Saprizal , Purwoko Agus Abhi , Rahmawati  , Hamdiani Saprini , Prananto Yuniar Ponco , Nuryono
Published: June 2019

Theoretical studies on the performance of corrosion inhibition of dibenzo-18-crown-6 compounds and its derivatives have been carried out using the B3LYP/631G(d) theory level. The effect of electron donor groups (NH2, OCH3, OH, CH3, CHCH2) and electron withdrawing groups (COOCH3, COOH, CHO, F, NO2) was also studied in the gas and aqueous medium. Electron donor groups increase the value of corrosion inhibition efficiencies; in contrast electron withdrawing groups have the opposite effects. The theoretical calculation indicated that NH2 gave the highest efficiency value, whereas the NO2 group gave the lowest corrosion inhibitor efficiency value. The positive correlation was shown between the corrosion inhibition efficiency and the quantum parameters. The Fukui function showed that the delocalisation of electrons around the benzene ring was the area that most contributes to the bond formed between the metal and the crown ether.
Identification of Bioactive Compounds in Ginger Based on Molecularly Imprinted Polymer Quartz Crystal Microbalance Gas Sensor
Authors: Hardoyono Fajar , Windhani Kikin , Sambodo Herman , Pudjianto Hary
Published: June 2019

Borneol, citral, and geraniol have been investigated as the major bioactive compound commonly found in ginger. In this work, a molecularly imprinted polymer (MIP) coated quartz crystal microbalance (QCM) sensor array has been employed for selective recognition of bioactive compounds in the ginger essential oil. In the experiment, the concentration of these bioactive compounds previously was measured using solid phase micro extraction gas chromatography-mass spectroscopy (SPME-GC/MS). Design of MIPs as the template of target molecules was created using polyacrylic acid (PAA) polymer matrix and three molecular targets (borneol, citral, and geraniol). An array of QCM sensor was prepared using four 9-Mhz AT-cut quartz crystal embedded between vacuum-deposited Au electrodes. For data recording, the headspace system flew the odorant of three varieties of ginger essential oil as positive control odorant and wild ginger essential oil as negative control odorant into the QCM sensor chamber. Then, mass loading in the MIP films caused frequency change of QCM sensor array due to odorant adsorption in a thin layer of MIP. Principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to analyse the QCM response sensor. PCA score plot showed segregation of feature response of ginger essential oil with and without the molecular target in the coordinate of principal components. Meanwhile, LDA was able to discriminate training datasets of 80 ginger samples containing borneol, citral, and borneol with accuracy more than 92.50%.
Parameter estimation for porang (Amorphophallus muelleri Blume) chips milling by using a batch type of ball mills
Authors: Hermanto M B , Widjanarko S B , Suprapto Wahyono , Suryanto Agus
Published: June 2019

Porang bulbs (Amorphophallus muelleri Blume) are native Indonesian bulbs which have high glucomannan content. It is almost similar to konjac bulbs (Amorphophallus konjac) which also glucomannan source. Porang flour is made from dried porang chips with about 10 % wet based water content. Unfortunately, there are no studies which were focused on the underlying mechanism of porang chip milling by using a batch type of ball mills. The objective of this research is to determine optimal milling rotational velocity and milling parameters of the kinetic model of porang chip milling by using ball mills. A batch type of ball mills was occupied in this research for milling 1.5 kg of dried porang chips. Optimal rotational velocity was calculated in order to have an optimal performance of milling. Kinetic model form of the back-calculation algorithm was chosen to describe the milling process. There were five estimated parameters of the validated kinetic model of the porang chip milling process.
Modelling Radiation Dose Distribution within Thorax using Monte Carlo Package Codes
Authors: Herwiningsih Sri , Fielding Andrew
Published: June 2019

In radiotherapy practice, it is difficult to measure radiation dose within patient anatomy. Although it is possible to do so, the technique would cause discomfort and pain to the patient due to the insertion of the radiation detector inside the patient’s body. Monte Carlo simulation offer a non-invasive technique to estimate radiation dose distribution within the patient’s body. This paper presents a work on modelling the radiation dose distribution within the thorax region in lung cancer treatment cases. EGSnrc/DOSXYZnrc Monte Carlo codes were employed in this study. Patient anatomy was modelled by converting the images data obtained from Computed Tomography (CT) scan to EGSPHANT files. Three CT images set from three lung cancer patients were used in this study. The simulated data were compared with the treatment planning data by using a gamma analysis with selection criteria of 3% dose difference and 3 mm distance-to-agreement. The results show that a good agreement was obtained between the simulated data and the treatment planning data which is indicated by the gamma analysis results of > 95%.
Development of Flow Injection-Spectrophotometry Method for Hydroquinone Determination Based on The Formation of Blue Starch-Iodine Complex
Authors: Trenggamayunelgi Fahrana Salas , Sulistyarti Hermin , Retnowati Rurini
Published: June 2019

Hydroquinone (1,4-dihydroxybenzene) is an aromatic organic phenolic compound used in drug and should not be used as cosmetic products. Although the use of hydroquinone has been banned in cosmetics, it is still found at low concentration for skin whitening. The effect for excess use of hydroquinone can cause irritation and changes in skin color become blackish permanently. The determination of hydroquinone can be performed by a flow injection system with spectrophotometric detection based on the redox reaction between hydroquinone and iodine. Under this method, hydroquinone can be determined based on the decreasing intensity of the blue color of the starch-iodine complex when hydroquinone was added to the solution. Hydroquinone will react with the excess iodine, thus iodine is reduced to iodide. The rest of iodine which does not react with hydroquinone, will form a blue complex with starch in an acidic condition (pH = 1). The blue color of the starch-iodine complex was analyzed by visible spectrophotometry at a wavelength of 628 nm. The optimum conditions for determination of hydroquinone using the flow injection system provide at 0.05 % starch and 40 mg/L iodine by the length of mixing coil of 50 cm on the flow rate of 5.8 mL/min, and a sample volume of 100 µL. Under these optimum conditions, the flow injection method showed the linearity from 0 to 15 mg/L with a correlation (R2) of 0.9941.
The Effect of Stirring Time on The Characteristics of Carbonated Hydroxyapatite from Pearl Shells (Pinctada maxima)
Authors: Anggraini R M , Yusuf Yusril
Published: June 2019

Carbonated hydroxyapatite (CHAp) is hydroxyapatite (HAp) substituted by carbonate ions that has bioactivity because of their similarities to the natural bone. Pearl shells (Pinctada maxima) have been used as natural ingredients for the synthesis of B type CHAp using precipitation method with different stirring time (0 h, 2 h, and 4 h). The CHAp was characterized by using X-Ray Diffractometer (XRD), Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy (SEM). The XRD results show the characteristics of B type CHAp from the position of the main peak and some diffraction plane, as well as from lattice constants a and c. The position of the main peak and plane (300) is above the position of pure HAp, plane (002) is below the position of pure HAp, and the lattice constants a are smaller than 9.418 Ǻ and c higher than 6.884. FTIR results showed that the main peak B type CHAp found at wavenumbers 874, 1450 and 1420 cm−1. According to the FTIR data, it can be concluded that stirring time variations was affecting the intensity of the functional group peaks. The smallest crystal deffect found in 2 h stirring sample based on the calculation of microstrain. SEM results indicated that CHAp morphology was affecting by stirring time. The morphology of CHAp tends to agglomerate for sample with 4 h stirring time.
Effects of Ni and Annealing Temperature on Crystal Structure and Magnetic Properties of MnNi-Fe2O4 Nanoparticles
Authors: Herdiman  , Saputra A I , Suharyadi E , Kato T , Iwata S
Published: June 2019

Manganese nickel ferrite (MnNi-Fe2O4) nanoparticles have been synthesized by co-precipitation method. In this research, the effects of Ni concentration (0.2-0.8M) and annealing temperature (400-1000°C) on the structural and magnetic properties of nanoparticles were studied. Ferrite samples were characterized by X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Fourier Transform Infrared (FTIR) spectroscope. The XRD patterns showed that nanoparticles possess cubic spinel structure that indicated by peaks of (220), (311), (400), (511) and (440). The crystallite size decreased with the increase of Ni concentration (23.5-4.5 nm) and increased with the increase of annealing temperature (14.8-49.3 nm). Stretching vibration on octahedral and tetrahedral of metal-oxygen from FTIR spectra was observed at 354.9 - 462.9 cm−1 and 586.3 - 601.7 cm−1, respectively. Magnetic properties of ferrite sample were analyzed by Vibrating Sample Magnetometer (VSM). The saturation magnetization (Ms) lay in the range of 11.07 – 20.7 emu/g and the Coercivity (Hc) decreases with the increase of annealing temperature (217.0 – 167.0 Oe).
Structure, Morphology, Electrical Transport, and Magnetoresistance Properties of La0.7Ba0.1Sr0.2Mn0.9Cu0.1O3
Authors: Kurniawan Budhy , Imaddudin Agung , Komala Tesya , Faruq Umar , Nur Alfin Naufal , Bisma Bathara , Razaq Dhawud Sabilur , Munazat Dicky Rezky
Published: June 2019

The structure, morphology, electrical transport and magnetoresistance properties of La0.7Ba0.1Sr0.2Mn0.9Cu0.1O3 has been investigated. The sample has been successfully prepared using sol-gel method. Structural investigation using X-ray diffraction (XRD) shows that the sample crystallizes in rhombohedral structure with R3c space group. The surface morphology of the sample shows that the sample consists of irregular polygonal grain. Furthermore, resistivity measurement shows that the sample undergoes a transition from metal to semiconductor behaviour upon heating. The electrical properties of the sample follow the electron-phonon-magnon scattering theory. Under the influence of the external magnetic field, the sample shows that up to 8% of the resistivity decreased at 200 K.
Effect of Calcium Carbonate on The Tensile and Density Properties of Kenaf/Polyester Hybrid Composite
Authors: Wicaksono S T , Laksana A H , Ardhyananta Hosta
Published: June 2019

Kenaf (Hibiscus cannabinus L.) was a plant belonging to the Malvaceae family. Kenaf was a natural fiber that has attracted researchers to explore its properties as reinforcement materials in composites. In addition, calcium carbonate (CC) particle can also improve the mechanical properties of composite. The aim of this study was to describe the fabrication of calcium carbonate particle reinforced kenaf/polyester hybrid composite. The hybrid composites were prepared using hand lay-up process with different particle loading (2.5%, 5%, 7.5%, 10% and 20% by weight). The hybrid composites were tested for tensile strenght using ASTM D368 standard. The highest tensile strength were showed for 5% wt calcium carbonate reinforced kenaf/polyester hybrid composite in this investigation. It was also observed that the density for hybrid composite decreased as the particle content increased.
Fabrication of Mixed Matrix Membrane Polysulfone - Zeolite Carbon Composites (ZCC) For Gas Separation
Authors: Larasati Z S , Wijiyanti R , Karim Z A , Ismail A F , Widiastuti N
Published: June 2019

Mixed matrix membrane polysulfone (PSF) - zeolite carbon composite (ZCC) was successfully fabricated in this study. The composition of ZCC as a filler in this membrane was 1%. Mixed matrix membrane PSF-ZCC 1 wt% was compared by neat polysulfone membrane. The prepared membranes were characterized using XRD to determine the membrane structure and FTIR to determine the functional groups in the membrane. The results of gas permeation for membrane permeability of O2 were 4.011 and 7.193 GPU for neat PSF and PSF-ZCC 1 wt% membrane, respectively. In addition, the permeability value of N2 was 5.603 and 7.862 GPU for neat PSF and PSF-ZCC 1 wt% membrane, respectively. Selectivities of O2/N2 for neat PSF and PSF-ZCC 1 wt% membrane were 0.715 and 0.914, respectively. The increasing permeability along with the addition of ZCC filler indicated that the membrane in this study is potentially applied for O2 and N2 separation.
Copper Nanoparticle Catalysed Aerobic Oxidation of α-pinene
Authors: Masruri  , Pamungkas K K
Published: June 2019

A green aerobic-oxidation of alpha-pinene using air and catalyzed by copper nanoparticle (CuNP) was studied. The study involved preparation and characterization of copper nanoparticle with three different calcination temperatures (300, 500 and 800°C). Nanoparticle characterization was conducted using FTIR spectrophotometry and SEM-EDX analysis. Evaluation of the catalytic activity was done using direct air-bubbled to the alpha-pinene with and without catalyst. It was found that oxidized alpha-pinene was formed as the major product.
Comparison of nutritive value between intact and defatted black soldier fly larvae for animal feed
Authors: Mulianda Randi , Ridla Muhammad , Laconi E B , Ridwan Roni , Jayanegara Anuraga
Published: June 2019

In this study, the possibility black soldier fly (BSF) larvae as a novel feedstuff for animal was investigated. The objective of this study was to compare the nutritive value between intact and defatted BSF larvae for animal feed by means of chemical composition determination and in vitro rumen fermentation technique. The following treatments were tested: intact BSF (T1), BSF low in lipid by mechanical extraction (T2), BSF low in lipid by chemical extraction (T3), and soybean meal (T4). The samples were subjected to proximate analysis, Van Soest’s fiber fraction and cell wall nitrogen determination. The samples were further incubated in vitro with buffered-rumen fluid in four replicates, represented by two incubation units per replicate, and conducted for 48 h at 39°C. Parameters measured in the in vitro evaluation were total gas production and methane emission at regular time point intervals. Other parameters measured after the incubation were dry matter degradation, organic matter degradation, total volatile fatty acid (VFA), ammonia concentration and pH. Data were tested using analysis of variance (ANOVA) and if there was a significant different at P<0.05 then continued with Duncan’s multiple range test. Results revealed that removal of lipid from BSF larvae either by mechanical or chemical extraction increased dry matter degradability (DMD), organic matter degradability (OMD) and total gas production values as compared to intact BSF (P<0.05). However, these values were still lower than those of soybean meal (P<0.05). Concentrations of ammonia and total VFA were similar across all dietary treatments. It can be concluded that removal of lipid from BSF larvae by either mechanical or chemical extraction improves its utilization in the in vitro rumen fermentation system.
The Chemical Properties of Seaweed Caulerpa lentifera from Takalar, South Sulawesi
Authors: Sinurat Ellya , Fadjriah Sofa
Published: June 2019

Indonesia is known as a maritime country having many types of seaweed. The type of seaweed that is still little studied is the type of green seaweed. One of the most common types of green seaweed found in Indonesia is Caulerpa lentifera. Green seaweed is informed to contain beta-glucan. Beta glucan has widely studied because it contains bioactive compounds. The bioactive content of green seaweed, in this case, is obtained from Caulerpa type. In this study, the type of Caulerpa studied derived from cultivation (Takalar, South Sulawesi). Test of chemical properties of seaweeds parameters observed were protein quality, fat content, carbohydrate, water content, and dietary fibre. This study is a preliminary treatment to determine the primary metabolite content of Caulerpa seaweed cultivation. The methods used to include rinsing, washing with water, drying and grinding. The result of analysis for moisture content (5.4%), protein (14.4%), fat (0.85%), total ash (41.85%) and carbohydrate (32.95%). Protein and carbohydrate were the most sources in this species. This study suggests that C. lentifera could potentially be used as a nutritious and functional food item for the human diet.