bluuebunny/crossref_metadata_2025_split huggingface dataset:
E-Comic mathematics based on STEAM-CC and its effect on students creative thinking ability
Authors: Hobri  , Adeliyanti S , Fatekurrahman M , Wijaya H T , Oktavianingtyas E , Putri I W S , Ridlo Z R 
Published: March 2021

Abstract
This research aims to create an e-comic mathematics based on Science, Technology, Engineering, Arts, and Mathematics – Caring Community (STEAM-CC) concept as well as to know its effect on the students’ creative thinking ability. Creative thinking is heavily influenced by approaching the students’ during the teaching and learning process. Moreover, it can be done through conducting small group students as a medium to collaborate, learn, and care each other along Caring Community (CC) in Lesson Study for Learning Community (LSLC). This study was used mixed method, 4D development method by Thiagarajan and experimental researcch. The result of this study showed that the developed e-comic was valid according to the material and media experts, while STEAM-CC concept was effective and practical way by looking at the students were able to achieve the standard minimun score on the test and observation. This research also found that the media can effect the studens’ creative thinking ability.
Eigenvalues of Adjacency and Laplacian Matrices of Bracelet—Kn
Graph
Authors: Albirri E R , Fatahillah A , Hussen S , Sugeng K A 
Published: March 2021

Abstract
Let G be an undirected simple graph. Adjacency matrix of a graph G, denoted by (A(G)), is defined as a matrix which has entry-(i, j) is equal 1 if vertex i and vertex j are adjacent and 0 if otherwise. Let D(G) be the diagonal matrix of vertex degree and J(G) be the matrix which has entry all ones. Laplacian matrix (L(G)) can be defined by L(G) = D(G) – A(G). This study discusses eigenvalues of adjacency and Laplacian matrices of the Bracelet—Kn
graph. The results of this study indicate that the Bracelet—Kn
graph for n ≥ 4, n even has four different eigenvalues of adjacency and Laplacian matrices.
Corrections for photons attenuation and scattering for the extrapolation chamber for measurement of air-kerma strength of 125I brachytherapy source
Authors: Liu C. , Song M. , Liu Y. , Wang H. , Wei K. , Hang Z. 
Published: March 2021

Abstract
A type of extrapolation chamber was designed in China Institute of Atomic Energy, CIAE. The chamber was used for the measurement of the air-kerma strength of the medical radiation 125I source on primary standard level. In order to obtain the air-krema strength with a low uncertainty, some correction factors such as photon attenuation and scattering are needed to calculate. Correction factors for different types of 125I seeds were estimated with increasing chamber depth. Based on the relation between ionization current and average photon fluence, attenuation correction factors were calculated with the analytical solution. Additionally, the scattering correction factors were estimated by a suitable method of Monte Carlo simulation. Photon attenuation includes four components. katt-volume, katt-foil, katt-sf, and katt-Al. The differences of correction factors are concerned, mainly due to the variation of chamer depths and 125I seed types. katt-volume increases from 1.001 to 1.005. katt-foil varies between 1.0012 and 1.0014. katt-sf changes from 1.015 to 1.018. katt-Al varies between 1.038 and 1.048, which largely depend on the photon spectrum from the source. Meanwhile, the geometric dimension of the ionization chamber has a great influence on the scattering correction factors. The ksca values vary from 0.9960 to 0.9964 with different chamber depths, which only has 0.04% fluctuation.
Automatic segmentation of fish midlines for optimizing robot design
Authors: Fetherstonhaugh Samuel E A W , Shen Qiang , Akanyeti Otar 
Published: March 2021

Abstract
While fish use continuous and flexible bodies to propel themselves, fish robots are often made from interconnected segments. How many segments do robots need to represent fish movements accurately? We propose a new method to automatically determine parsimonious robot models from actual fish data. We first identify key bending points (i.e., joint positions) along the body and then study the concerted movement of the segments so that the difference between actual fish and modelled bending kinematics is minimized. To demonstrate the utility of our method, we analyse the steady swimming kinematics of 10 morphologically distinct fish species. Broadly classified as sub-carangiform (e.g., rainbow trout) and carangiform (e.g., crevalle jack) swimmers, these species exhibit variations in the way they undulate when traditional parameters (including head and tail beat amplitudes, body wavelength and maximum curvature along the body) are considered. We show that five segments are sufficient to describe the kinematics with at least 99% accuracy. For optimal performance, segments should progressively get shorter towards the tail. We also show that locations where bending moments are applied vary among species, possibly because of differences in morphology. More specifically, we find that wider fish have shorter head segments. We discover that once bending points are factored in, the kinematics differences observed in these species collapse into a single undulatory pattern. The amplitude and timing of how body segments move entirely depend on their respective joint positions along the body. Head and body segments are also coupled in a timely manner, which depends on the position of the most anterior joint. Our findings provide a mechanistic understanding of how morphology relates to kinematics and highlight the importance of head control, which is often overlooked in current robot designs.
Multi-decadal improvement in US Lake water clarity
Authors: Topp Simon N , Pavelsky Tamlin M , Stanley Emily H , Yang Xiao , Griffin Claire G , Ross Matthew R V 
Published: March 2021

Abstract
Across the globe, recent work examining the state of freshwater resources paints an increasingly dire picture of degraded water quality. However, much of this work either focuses on a small subset of large waterbodies or uses in situ water quality datasets that contain biases in when and where sampling occurred. Using these unrepresentative samples limits our understanding of landscape level changes in aquatic systems. In lakes, overall water clarity provides a strong proxy for water quality because it responds to surrounding atmospheric and terrestrial processes. Here, we use satellite remote sensing of over 14 000 lakes to show that lake water clarity in the U.S. has increased by an average of 0.52 cm yr−1 since 1984. The largest increases occurred prior to 2000 in densely populated catchments and within smaller waterbodies. This is consistent with observed improvements in water quality in U.S. streams and lakes stemming from sweeping environmental reforms in the 1970s and 1980s that prioritized point-source pollution in largely urban areas. The comprehensive, long-term trends presented here emphasize the need for representative sampling of freshwater resources when examining macroscale trends and are consistent with the idea that extensive U.S. freshwater pollution abatement measures have been effective and enduring, at least for point-source pollution controls.
Generalised Airy polynomials
Authors: Clarkson Peter A , Jordaan Kerstin 
Published: March 2021

Abstract
We consider properties of semi-classical orthogonal polynomials with respect to the generalised Airy weight

ω

(

x
;
t
,
λ

)

=

x

λ

exp

−

1

3

x

3

+
t
x

,

x
∈

R

+

with parameters λ > −1 and

t
∈
R

. We also investigate the zeros and recurrence coefficients of the polynomials. The generalised sextic Freud weight

ω

(

x
;
t
,
λ

)

=
|
x

|

2
λ
+
1

exp

−

x

6

+
t

x

2

,

x
∈
R

arises from a symmetrisation of the generalised Airy weight and we study analogous properties of the polynomials orthogonal with respect to this weight.
Influence of asymmetric factor on spur gears to dynamic bending stress
Authors: Pramono Agus Sigit , Rizal Mohamad Zainulloh 
Published: March 2021

Abstract
Asymmetric spur gear is used in one-way rotation transmission. This spur gear has a higher bending strength than symmetric spur gear. In this research, the effect of asymmetrical spur gear level on bending stresses is studied dynamically. The asymmetric spur gear level is expressed as asymmetric factor (K). Asymmetric factors K = 1, K = 1.05, K = 1.06, K = 1.07 and K = 1.08 are used. Dynamic analysis is performed by explicit dynamics numerical modeling. Material used for five asymmetric factor is AISI 1045. Two variables applied on this spur gears are torque loads and rotational speeds to investigate that effect on bending stress. Torque loads varied from 100 Nm to 250 Nm with 50 Nm increment and rotational speeds varied from 1000 rpm to 2500 rpm with 500 rpm increment. The results of this study show that the asymmetric factor can reduce more significantly bending stress cause of torque loads than cause of rotational speeds.
Kijang LGX camshaft’s failure analysis using the finite element method approach
Authors: Prasetya Riduwan , Andoko  
Published: March 2021

Abstract
The camshaft on the Kijang LGX was broken after 14 years of use. This study aims to determine causes of camshaft fracture using finite element approach. The software used is Solidworks and ANSYS 17.0 for FEM simulation. The results to be obtained from the simulation results are stress, strain, and deformation which are then analyzed. The results showed that the greatest stress occurred in the fillet section where the area with highest stress concentration was 168.93 MPa. This value is smaller than the compressive strength so that the applied stress is within the limits of the strength of the material. Maximum stress location is 7 mm away from the fracture site (53.17 MPa), therefore the stress is not the main cause of the camshaft fracture and it can be assumed that there is a defect. The maximum strain is located at the same location as the maximum stress which is 0.0015361 mm/mm. The maximum deformation value is 0.016741 which is far from the fracture (located at the end of the cam). This value is included in the elastic deformation of the material so that the load applied to the camshaft does not change shape / does not lead to plastic deformation that triggers the appearance of cracks.
Strength consideration on car body of light rail transit making from aluminum extrusion
Authors: Syaifudin Achmad , Nurfadillah Egy Meirarizka , Farid Abdul Rohman , Windharto Agus 
Published: March 2021

Abstract
There are two common series of aluminum alloy that used to construct car body of light rail transit (LRT), i.e. Al 6061 and Al 6005a. Type of Al 6005a has lower strength but cheaper rather than Al 6061. In this numerical study, their extrusion characteristics based on strength consideration are analyzed using ANSYS Workbench 18. The 3D solid model is extracted from interior-exterior facet models of LRT. To save computational time, the car body model is simplified by removing fillets and then generating a symmetrical model. Anyhow, the effect of fillet removal is also studied by introducing a correction factor. Four cases of static loading are given to observe actual loading phenomena that could occur. The simulation results indicated that Al 6005a has better characteristics to be used for constructing the car body of LRT. In addition, simplifying the model in the FEM simulation of a rail-based car body using a shell element type and applying a correction factor to the simulation results is a breakthrough simulation method that could improve the accuracy of the results.
Experimental study of thermoelectric cooler box using heat sink with u-shape heat pipe and methanol working fluid
Authors: Winarta Adi , Made Rasta I , Ike Midiani Luh Putu , Wayan Adi Subagia I , Gde Sapteka Anak Agung Ngurah 
Published: March 2021

Abstract
Thermoelectric refrigeration system is considered environmentally friendly because it does not use refrigerants which have huge potential damaging the ozone layer. In this experimental work, u-shape heat pipe with heat sink was charged with methanol working fluid with different filling ratios to observe its effect on the thermoelectric performance. The cooler box has 240 mm x 180 mm x 130 mm of inner dimension. 37.3 watt DC power supply supplied constantly to the thermoelectric module to performed cooling action. The result shows that methanol with 45% and 55% filling ratios has the maximum COP about 0.03881 and 0.03885 respectively. This filling ratio also provides for a lower cabin temperature and temperature difference between the cold and hot thermoelectric sides.
Droplet combustion behavior of crude palm oil-carbon nanoparticles blends
Authors: Marlina Ena , Nanlohy Hendry Y. , Gusti Ketut Puja I , Riupassa Helen 
Published: March 2021

Abstract
Research on the combustion behavior of a mixture of palm oil and carbon nanoparticles has been carried out. The burning phenomenon is observed through oil droplets that are ignited at the thermocouple junction, and the evolution of the droplets is recorded with a high-speed camera. The results indicate that the addition of carbon nanoparticles increases the molecular density of the fuel. This has the potential to produce effective collisions that weaken the strength of carbon chain bonds and increase the reactivity of fuel molecules. The increased motion of fuel molecules makes it easy for molecules to absorb heat and burn. This analysis was proven because the results showed that the addition of carbon nanoparticles succeeded in increasing the temperature and burning rate.
Effect of performance generator set 1.5 PK 4 stroke with variations in load and type of spark plugs
Authors: Paristiawan Permana Andi , Simanullang Bantu Hotsan , Saefudin  
Published: March 2021

Abstract
Energy is one of the most important needs for humans, and electricity is one of the energy needs needed to support various human activities both day and night. One source of electrical energy is obtained by using a generator as a power plant. The generator set is used as a backup when the electricity supply from PLN is cut off.Efforts to get a good performance generator set are made by improving the combustion quality to increase efficiency. Tests carried out on a four-stroke one cylinder generator capacity of 1.5 PK with variations in load and type of spark plugs are standard, platinum, and iridium, which at 3000 rpm engine speed with a load of 350, 700 and 1050 Watt pertalite fuel with a volume of 10 ml. The value of Torque and power has increased along with the increased engine load. The optimum generator performance is obtained at a load of 700 watts when using this type of platinum spark plug. The maximum engine power generated is 1,092 HP. Torque of 2.59 Nm and the lowest fuel consumption (SFC) of 0.484 kg/hp.hour.
Experimental investigation on the effect of carbon chain length to the droplet combustion characteristic of fatty acid methyl ester
Authors: Ibadurrohman Ibrahim Ahmad , Hamidi Nurkholis , Yuliati Lilis , Valentino Benedict Amadeus 
Published: March 2021

Abstract
Biodiesel which produces from vegetable oil consists of various fatty acids as fatty acid methyl ester constituent. Each fatty acid has a specific combustion characteristic due to the difference in physicochemical characteristics. This study was done with a single fatty acid methyl ester from various saturated fatty acids to analyze the effects of carbon chain length on the droplet combustion during the evaporation and combustion stages in ambient temperature and atmospheric pressure. Results show that the ignition delay time increase with the longer carbon chain due to the higher viscosity and boiling point. The higher oxygen content in the fatty acid methyl ester molecule promotes the faster combustion, gives a higher burning rate, and cause the flame dimension shorter. Furthermore, oxygen content results in higher radiation caused a brighter flame. The high droplet temperature occurs in the long carbon chain due to the higher of combustible matter gives an increase to the heating value. Low radiation heat loss in a long carbon chain which indicates by the flameless bright also causes the droplet temperature higher. The higher droplet temperature gives the lower gas density which causes the flame dimension higher due to the natural convection.
Performance of diesel engine using cooking oil biodiesel (B20) with additional bioaditive essential oils (Eucalyptus)
Authors: Permanasari Avita Ayu , Sukarni Sukarni , Wulandari Retno , Hamidi Nurkholis , Ramadani Ramadani , Mauludi Muhammad Najib 
Published: March 2021

Abstract
This research is geared by the depletion of the availability of fossil fuels in nature. This is inversely proportional to the level of fossil fuel consumption, which is getting higher from year to year. Thus, there is a need for alternative fuels. One of which is biodiesel. The existence of an assessment in preparing biodiesel as an alternative fuel is significant. This study aims to determine the effect of the addition of bioaditive essential oil (eucalyptus) on the performance of diesel engines. The method used in this research was the manufacture of biodiesel through esterification and transesterification steps, then testing the diesel engine to determine the performance and gas emissions were also carried out. The results show that brake torque has decreased along with the loading at each engine speed. The value of brake power increases from 1700 rpm to 1900 rpm and then decreases to 2300 rpm. Brake fuel consumption increases with increasing engine speed, and thermal brake efficiency decrease with increasing engine speed. The CO emission is constant, but in the B20 biodiesel sample with 0.1% eucalyptus oil additive, the CO emission increases to 2100 rpm. CO2 and HC emissions fluctuate with an increasing trend with increasing engine speed. O2 emissions fluctuate with a decreasing trend along with the increase in engine speed, the O2 content produced by pure biodiesel B20 is lower than B20 with additives
Identification of gradient temperature and heat flow area of geothermal Ijen Volcano Indonesia
Authors: Afandi Akhmad , Lusi Nuraini , Catrawedarma IGNB , Badarus Zaman M. , Subono  
Published: March 2021

Abstract
A researcher carried out a study about gradient temperature and heat flow in the field of regional area of solfatara Ijen Banyuwangi Regency, East Java province, Indonesia. It is according to the temperature from the surface to about 100 cm deep, while making use of thermocouples with the accuracy of ± 0.5 % and ± 1 °C. Coordinate position measurements using a Garmin GPS device. This research aims to study the distribution of the temperature at any given depth, which is the gradient of temperature at a depth of 2000 m and the value of heat transfer through conduction. Temperature distribution of the depth contour, there are zones with high-temperature, and they increase along with the increase in depth. The gradient of temperature is 35 °C m−1 at a depth of 2000 meters generates 175.6 °C. The maximum heat flow value is always obtained in the presence of sulfur, while the average heat flow of solfatara on the field is 21.08 W m−2.
Adding the activated carbon of rice husk to increase hydrogen production on water electrolysis
Authors: Purnami  , Wardana ING. , Sudjito  , Widhiyanuriyawan Denny , Hamidi Nurkholis 
Published: March 2021

Abstract
Water electrolysis is decomposing water (H2O) into Oxygen and Hydrogen with the help of electric current. At present, the conventional electrolysis efficiency is around 50%. The use of catalysts is partly engineered to increase the hydrogen production. In this paper, activated carbons from rice husk (RHAC) of 50 ppm and 100 ppm were added as the catalyst to increase Hydrogen production. FTIR tests showed that RHAC had an aromatic ring functional group with magnetic field. By the help of ImageJ software, it was proven that RHAC surface has an electric charge dominated by a positive charge. The magnetic field weakens the hydrogen bonding, while the electric charge increases the solution acidity, and makes it a good electrical conductor. As a result, greater addition of RHAC increases Hydrogen production. The largest hydrogen production of 8.2 ml for 10 minutes was obtained by the addition of 100 ppm.
Preliminary study of FCC design for palm-based biofuel production through heat balance analysis
Authors: Hilman Gumelar Syafei M. , Siswantara Ahmad Indra , Budiarso  , Widiawaty Candra Damis , Farhan Tanwir Ahmad , Pujowidodo Hariyotejo , Ramdlan Gunadi Gun Gun 
Published: March 2021

Abstract
Fluid Catalytic Cracking (FCC] is playing a big role in oil refinery industries and it has been used for producing most of the fuel around the world. FCC has also a great potential for producing biofuel derived from palm-based bio oil. However, it takes a complex calculation to design the overall FCC system. This paper offers the design simplification of FCC through heat balance analysis in two main components, that is riser section and regenerator section. The objective of this study is to estimate the appropriate amount of fuel for a given amount of feed. It is obtained that the required amount of fuel is greater as amount of the given feed increased.
Effect of natural zeolite on biomass pyrolysis
Authors: Bahri Mokh. Hairul 
Published: March 2021

Abstract
Study the pyrolysis of biomass with the addition of natural zeolite to determine the enthalpy required to become gas, oil, and char. The materials used were Sengon (S) sawdust and natural zeolite type Clipnotilolite (Z). The pyrolysis process used STA Iliensies PTA 1600. The test samples S, S + Z1, S + Z2, and S + Z3 were heated at a heating rate of 20 °C min−1 and an air flowrate (Argon) of 0.5 liters min−1. The result shows that the enthalpy of pyrolysis S decreases with the increase of Z. The greater the percentage of Z the decrease in enthalpy is getting sharper, while the decrease in mass is relatively small.
The influence of increased carbon content on the number of electrons in dye-sensitized solar cell (DSSC)
Authors: Trihutomo Prihanto , Marji  
Published: March 2021

Abstract
Dye-Sensitized Solar Cell (DSSC) is a solar cell that uses sensitive dye toward visible light to convert light into electricity. The sensitive dye that are commonly used are chlorophyll which contains many elements of carbon. The carbon element in chlorophyll contains electrons which can generate an electric current in the DSSC. This research has proven that increasing the carbon content of dye can increase the number of electrons generated in the DSSC. The method used in this study was to vary the dye content of TiO2, namely dye concentrations of 25%, 50%, 75% and 100%. The results showed that increasing the dye content would increase the carbon content and the number of electrons generated by the DSSC, namely that the 100% dye content had a carbon content of 1.414% and the number of electrons was 0.22 x 1019.