bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resolving Hubble tension with quintom dark energy model *
Authors: Panpanich Sirachak , Burikham Piyabut , Ponglertsakul Supakchai , Tannukij Lunchakorn 
Published: October 2020

Abstract
Recent low-redshift observations have yielded the present-time Hubble parameter value

. This value is approximately 10% higher than the predicted value of

, based on Planck's observations of the Cosmic Microwave Background radiation (CMB) and the

CDM model. Phenomenologically, we show that, by adding an extra component, X, with negative density to the Friedmann equation, it can address the Hubble tension without changing the Planck's constraint on the matter and dark energy densities. To achieve a sufficiently small extra negative density, its equation-of-state parameter must satisfy

. We propose a quintom model of two scalar fields that realizes this condition and potentially alleviate the Hubble tension. One scalar field acts as a quintessence, while another “phantom” scalar conformally couples to matter such that a viable cosmological scenario is achieved. The model only depends on two parameters,

and

, which represent the rolling tendency of the self-interacting potential of the quintessence and the strength of the conformal phantom-matter coupling, respectively. The toy quintom model with

(Quintom I) yields a good Supernovae-Ia luminosity fit and acceptable

fit but slightly small acoustic multipole

. A full parameter scan revealed that the quintom model was superior to the

CDM model in certain regions of the parameter space,

, while significantly alleviating the Hubble tension, although it is not completely resolved. A benchmark quintom model, Quintom II, is presented as an example.
One-pot synthesis of spirooxindole-pyrrolizidine compounds using magnetically separable Fe3O4-graphene oxide (Fe3O4-GO) catalyst
Authors: Hapsari M , Cahyana A H , Yunarti R T 
Published: October 2020

Abstract
A couple of novel Spirooxindole-pyrrolizidine compounds have been synthesized from chalcone derivatives as α, β-unsaturated carbonyl compounds by the help of heterogeneous magnetically separable Fe3O4-GO catalyst. Four steps involved in this research are synthesis of Fe3O4-GO catalyst, synthesis of chalcone derivatives from 4-hydroxybenzaldehyde and cinnamaldehyde, synthesis of spirooxindole-pyrrolizidine derivatives by 1,3-dipolar-cycloaddition reaction through the formation of azomethine ylide, and the last is antioxidant activity assay using DPPH method. The result showed that the use of Fe3O4-GO catalyst as much as 5 wt% can increase the reaction yield to 86.27 %. From the DPPH assay, it is known that spirooxindole-pyrrolizidine derivatives have an antioxidant activity but spirooxindole-pyrrolizidine derived from 4-hydroxybenzaldehyde is the better one.
Phase system of hexane-water for SnO2 nanoparticles preparation using Cassia alata leaf extract and its photocatalytic activity
Authors: Hakim F L , Yulizar Y , Apriandanu D O B 
Published: October 2020

Abstract
SnO2 nanoparticles (NPs) were prepared using a hexane phase of Cassia alata leaf extract (CLE) and a water phase of SnCl2 precursor by high-speed stirring (HSS) method. In this study, HSS was utilized to analyze the nanoparticle formation via phase system of hexane-water. Next, the synthesized SnO2 NPs were characterized by Fourier transform infrared (FT-IR) spectroscopy, particle size analyzer (PSA), transmission electron microscopy (TEM), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDX), UV-Vis diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). Phytochemical screening confirms that CLE contains secondary metabolites such as alkaloids as a source of base, saponins and tannin as a capping agent in SnO2 NPs formation. TEM characterization shows that the particle size of SnO2 NPs was approximately 25–50 nm. The photocatalytic activity of SnO2 NPs was tested for methylene blue (MB) degradation under UV light irradiation. As a result, the degradation percentage of MB was 70.29 % for 160 min.
Sixth-generation of ziegler-natta catalyst for homopolymer polypropylene polymerization: Effect to product properties and regulation
Authors: Syahrudin R I , Herlambang B A 
Published: October 2020

Abstract
The development of catalysts for polypropylene (PP) polymerization has begun since Ziegler-Natta (Z-N) discovered the catalyst for polyethylene polymerization. However, the first-generation catalyst which was a combination of TiCl3-AlEt2Cl (catalyst-co-catalyst) has low productivity and isotacticity. The modifications continue to be made to increase the productivity and isotacticity by combining the Z-N catalyst with MgCl2, internal donors, and external donors. The fourth-generation Z-N catalyst, TiCl4/Phthalate/MgCl2-AlEt3/Silane, has given satisfactory results with high productivity and isotacticity. Another concern arose when phthalate derivatives turned out to be able to initiate cancer formation. This problem has led catalyst development to the sixth-generation Z-N catalyst with a phthalate-free internal donor. This research intends to study the effects of sixth-generation catalysts to polypropylene properties when compared to the fourth-generation catalysts. We produced homopolymer polypropylene (HPP) by fourth- and sixth-generation of Z-N catalyst with the same polymerization technology. Then, the effects on product properties, namely melt flow rate (MFR), xylene soluble, residual catalyst, physical properties, optical properties, and rheological properties were observed. Sixth-generation catalyst exhibited a better stereoregularity and it made a better flexural modulus. The rheological properties showed the sixth-generation catalyst products have lower molecular weight and it generates fewer gels and lower impact strength. Sixth-generation catalyst also exhibited lower catalyst residue which allows lower dosage of an acid scavenger with comparable color performance. With increasingly strict restrictions on the use of phthalates, the sixth-generation catalyst is more convenient to use. In terms of the effect on the polypropylene properties, fourth-and sixth-generation catalysts have their respective advantages.
Effect of film fabricating conditions and its implications on mechanical properties of high-density polyethylene film
Authors: Herlambang B , Anando M R O B 
Published: October 2020

Abstract
The use of plastics, especially High-Density Polyethylene (HDPE) film has increased rapidly in recent years due to its low cost, lightweight and excellent mechanical properties which is depended on the extrusion condition in the owner’s film fabrication machine. The blown film process is the common process used to make a thermoplastic film in large volumes. However, many research performed long ago in the mechanical properties of polyethylene only concerned on the effect of conventional processing parameters such as temperature and pressure in blown film machines and neglected the significant effect of critical extrusion conditions. We did the study to know the effect of critical extrusion conditions such as output rate, blow-up ratio (BUR) and neck-point height (NPH) which was intended to get the optimum film fabrication conditions in a blown film extrusion machine. Each parameter was performed in five different conditions by increasing one parameter and controlling the other. The resin first melted, conveyed, and delivered before finally blown to form the film. The mechanical properties observed were impact resistance, tensile strength, elongation, tear strength, and young modulus. The result indicates that increasing the output rate, BUR and NPH imparted in the film’s orientation balance, bubble shape, relaxation, and crystallization effects will lead to the increase of impact resistance, decrease of tear strength, and balance of film direction properties. The excessive and low amount of output rate, BUR and NPH are not desirable as it decreases the mechanical properties from HDPE film whether in mechanical direction or transverse direction. Hence, the optimum operating condition depends on which mechanical properties that needed to be achieved by film fabricators.
Synthesis and characterization of zinc-aluminum and zinc-chromium LDHs intercalated citrate anion
Authors: Hidayati N , Azmi M F , Oktriyanti M , Palapa N R , Mohadi R , Elfita  , Lesbani A 
Published: October 2020

Abstract
In this study, the preparation of Zinc-Al and Zinc-Cr LDH intercalated by citrate anion conducted using co-precipitation method at room temperature. The characterization of Zinc-Al and Zinc-Cr LDHs intercalated citrate anion was performed using XRD and FTIR. The result of XRD pattern and FTIR spectra confirmed that Zinc-Al and Zinc-Cr intercalated citrate anion were successfully prepared. The vibration of citrate anion observed at 1590 cm−1 and 1390 cm−1, respectively, correspond to the characteristic of the carboxylate group (-COO-). Structure of Zinc-Al and Zinc-Cr LDHs were shown by reflection at 2 theta (003) that indicated the interlayer space was higher than before intercalation.
Simple isolation method of cannabinol from Cannabis sativa to produce secondary reference standard analysis material
Authors: Hidayati N , Saefumillah A , Cahyana A H 
Published: October 2020

Abstract
The simple isolation method of Cannabinol compounds from cannabis plants by maceration combined with ultrasonication assisted extraction, fractionation, separation and purification was carried out to obtain Cannabinol isolates which can be used as a reference standard analysis material. Ultrasonication was proven to shorten the extraction time, where extraction for 5 h with ultrasonication assisted for 15 min produced 5.536 % yield greater than the 24 h extraction. The results of extraction were fractionated using n-hexane and then chromatographically isolated with a column containing Silica Gel 60, with 2.5 cm diameter and a 15.3 cm height, eluted by n-hexane-ethyl acetate (90:10) solution. The fraction containing Cannabinol was purified using HPTLC preparative with eluent n-hexane-ethyl acetate (80:20). The purification of the Cannabinol isolate was further characterized by Spectrophotometer UV, FTIR, DCS, GCMS and LCMSMS and compared its profile to the reference standard of Cannabinol from Lipomed. The characterization results showed that the purified isolates had UV spectra with λ max at 219.0 nm and 284.5 nm, FTIR spectra at wave numbers 1620.21 cm−1, 1051.20 cm−1, 1581.63 cm−1, 1026.13 cm−1, 1128.36 cm−1 and 1232.51 cm−1. The DSC thermogram shows the melting point of compound is 74.36 °C with 99.35 % purity, GCMS fragmentation at m/z 295, 296, 238 and 310, LCMSMS with [M + H]+ at 311.1 and MS2 at 222.95, 292.95 and 240.95 confirmed the chemical structure of the compound. The results of the characterization of pure isolates indicate that the compound produced was Cannabinol in accordance with the standard characterization profile of the reference standard of Cannabinol used.
Phytochemical and antiacne investigation of Indonesian White Turmeric (Curcuma zedoaria) Rhizomes
Authors: Setyani D A , Rahayu D U C , Handayani S , Sugita P 
Published: October 2020

Abstract
White turmeric (Curcuma zedoaria) is one of plant species belongs to Zingiberaceae from Himalaya, India. Previous research showed that the rhizomes of this plant contained several secondary metabolites such as alkaloid, phenolic, and terpenoid which commonly known to have antibacterial activities. This study aims to investigate the phytochemical of white turmeric rhizomes growth in Indonesia and evaluate its antibacterial activity against Propionibacterium acnes and Staphylococcus epidermidis as acne-causing bacteria. In this study, secondary metabolites from Indonesian white turmeric rhizomes were successfully extracted in methanol and partitioned in polarity increasement of several organic solvents. Furthermore, crude and all partitioned extracts were subjected to phytochemical investigation. The ability of crude and ethyl acetate extracts to inhibit the growth of P. acnes and S. epidermidis were evaluated using disk diffusion method. According to the antibacterial activity results, all of samples did not exhibit antibacterial activity against both acne-causing bacteria. The results of this study will provide a useful information regarding the phytochemical and antiacne investigation of Indonesian white turmeric rhizomes.
Activity of hydrogenated curcuminoid on Pd/C catalyst and its antibacterial activity against Staphylococcus aureus and Streptococcus mutans
Authors: Adriani N H , Rahayu D U C , Saepudin E 
Published: October 2020

Abstract
Turmeric (Curcuma longa) has been known for its benefit as one of medicinal herbs. Curcuminoids, the active compounds in turmeric, consist of three structurally related compounds, curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Curcuminoid has been reported to be effective for the treatment of chronic gingivitis and hence it can be a potential candidate to be used as an active ingredient for antimicrobial in a mouthwash. However, its yellow color has hampered its application as a mouthwash as it may cause the aesthetical problem to the teeth. In this study, curcuminoids, obtained from Soxhlet extraction of turmeric powder, were reduced by hydrogenation on Pd/C catalyst to remove the color. TLC analysis revealed that the products consist of three compounds as expected. The product was purified from unreacted curcuminoids by column chromatography on silica gel, to obtain a colorless product with percent conversion of 23.45 %. These three compounds were characterized by Uv-Vis spectrophotometer resulted in three peaks in three different wavelengths: 282, 283 and 280 nm. Characterization with FT-IR spectrometer showed an increase intensity of CH-sp3 peak (2932 cm−1) when compared to the IR spectrum of standard curcuminoids, and the shift in C-O absorption (1231 cm−1), indicated the existence of methoxy groups that can distinguish one to the other compounds. These three compounds then were evaluated for their antibacterial activity against Staphylococcus aureus and Streptococcus mutans. The result showed that the tetrahydrocurcumin had moderate antibacterial activity against S. aureus with inhibition zone of 5.5 mm and tetrahydro desmethoxycurcumin also showed moderate antibacterial activity against S. mutans with inhibition zone of 5.5 mm.
Characterization and Dielectric Properties of Fly Ash / Polystyrene / Low Density Polyethylene Composites
Authors: Nasr G M , Mohamed T A , Ahmed R M 
Published: October 2020

Abstract
Polystyrene (PS) and its blend with low density polyethylene (LDPE) were prepared by melting method. Fly ash was used as filler with different contents to form composites by the same way with PS/LDPE 80/20 blend. The obtained data of fly ash from X-Ray Fluorescence analysis displayed that the total mass summation of silicon, magnetite and aluminum (SiO2 + Fe2O3+ A12O3) is about 79.52 wt. % whereas the amount of calcium oxide is less than 10%. TGA curves showed that the sample of the more thermal stability was the composite that contains the highest amount of fly ash (50 wt.%). For all the samples, the dielectric constant and the dielectric loss were increasing by decreasing the applied frequencies while they were decreasing by increasing the temperatures. Also, increasing the fly ash content in the blend improved the ac conductivity up to a content of 40 wt.% then it decreased. The values of the real part of the electrical modulus (M’) did not equal to zero at low frequencies and high temperature. Therefore, it is expected that the electrode polarization may take place for the all samples.
Fano Resonance Properties in (K3C6o / HgBa2Ca2Cu3O10) 1D photonic crystal
Authors: Aly Arafa H , Mohamed D. , Abd El-Gawaad N. S. , Matar Z. S. , Trabeisi Y. , Mohaseb M. A. 
Published: October 2020

Abstract
The Fano resonance and Electromagnetic induced reflectance (EIR) properties in one-dimensional superconductor photonic crystals (SPCs) have been investigated theoretically by Transfer Matrix Method (TMM). The periodic structure consists of alternating of pair superconductor materials are made of (K3C60/HgBa2Ca2Cu3O10) one-dimensional photonic crystal. The SPCs is enclosed by dielectric cap layer at different induced fields. To exam the efficiency of the reported structure, different parameters are used for analysis such as layers thicknesses, temperature, angle of incidence and the dielectric constant, dielectric cap layer on the EIR and Fano line shape. The investigation results exhibits tunable Fano resonances and EIR resonance peaks accompanied by asymmetrical line shape very sensitive to dielectric cap layer, constituent materials and dependence incidence angle. This will be useful reference for different applications of photonic topological states in the integrated photonic devices and information processing chips.
The Effect of burnable absorbers on neutronic parameters of VVER-1200 reactor
Authors: Hafez Noura , Shahbunder Hesham , Amin Esmat , El-Kamessy S. U. , Elfiki S. A. , Latef Ahmed 
Published: October 2020

Abstract
The presence of burnable absorbers play an important role in the safety of nuclear reactors. So, seeking their influences on the reactor core behaviour is a crucial issue in both reactor core design and operation. Therefore, the aim of the present work is to study the effect of the gadolinium oxide burnable absorbers on one of the significant safety parameters of WER-1200/V392M core which is the neutron flux distribution. A full-scale three-dimensional model of the WER-1200/V392M core was performed using MCNP5/MCNPX transport code with ENDF/B-VII.O nuclear data library. The calculations were performed in the normal operation state for the first fuel cycle. Besides the neutron flux in both radial and axial distributions, the comparison between the fuel assemblies contained gadolinium oxide and that without gadolinium oxide is also discussed. Also, the effect of gadolinium oxide on the produced major actinides is investigated.
Tunable filter based on the 1D photonic crystal within ultraviolet radiations
Authors: Aly A. H. , Barakat S. , Amin A. F. 
Published: October 2020

Abstract
In the present study, we develop a one-dimensional semiconductor photonic crystal to control ultraviolet radiation. We study the transmittance spectra of incident light on the proposed structure in the ultraviolet regime. A photonic bandgap appears with a width of 95.2 nm. by changing the thickness parameters, it can reach up to 125.6 nm with appearing of new band gaps. The incident angle effect on the band gap’s width is apparent. The bandgap shifted to a lower wavelength region. So the proposed structure could be useful in preventing UV radiation from passing through it.
Effect of UV-activated TiO2 Nanoparticles on the Properties and Performance of PAni-TiO2 Nanocomposite Films for Solar Cell Applications
Authors: El-Hossary F. M. , Ghitas A. , Abd El-Rahman A. M. , Ebnalwaled A. A. , Abdelhamid Shahat M. , Fawey M. H. 
Published: October 2020

Abstract
To improve the performance of organic solar cells by enhancing the properties of the photoactivated nanocomposite layer, the UV irradiation process was used to activate titanium dioxide nanoparticles (TiO2 NPs). Herein, polymer solar cells were fabricated with FTO/(PAni-TiO2)/Ag system. A series of mixed polyaniline (PAni) with 20% of activated TiO2 NPs at different processing times was used to form PAni-TiO2 nanocomposite films. The structural evolution, surface characteristics, optical and electrical properties of PAni-TiO2 films have been investigated. XRD patterns showed that the UV treatment of TiO2 NPs increased the crystallite from 18.35 to 24.1 nm and the degree of crystallinity increased by 5.6%. The irradiated PAni-TiO2 films showed a rougher and more porous surface compared to the untreated one. Moreover, the adhesion force and electrical conductivity of the treated nanocomposite films at 8 h improved to be 137 mN/m and 6.62 S/m, respectively. Incorporation of activated TiO2 NPs exposure to UV for different times from 0 to 8 h with the PAni matrix enhanced the current density (Jsc) of PAni-TiO2 based nanocomposite solar cells from 3.11 to 4.83 (mA/cm2) and their efficiency from 0.33 to 0.85%. The increase in the solar cell efficiency is mostly ascribed to a structural change accompanied by a rapid increase in surface roughness, which led to a decrease in the reflected photons and thus an increase in the charge carriers produced. These results revealed the effect of surface UV irradiation of TiO2 NPs on their structural properties and the electronic contact between PAni and TiO2 NPs, which greatly influenced the amount of carrier transport within the PAni-TiO2 composites.
A Civics Primer for American History
Authors: Ortiz Paul 
Published: October 2020

Abstract
This AHR Roundtable features four short essays on Jill Lepore’s widely read synthesis of American history, These Truths: A History of the United States (2018). Lepore’s framework insists that the “self-evident” truths of the nation’s founding were anything but. The driving force of her narrative is the struggle of those excluded from this magic circle—really, the majority of the country’s population—to extend those truths beyond their narrow core of elite white men. The four reviewers—Ned Blackhawk, Matt Garcia, Mary Beth Norton, and Paul Ortiz—appreciate the “shared sense of national destiny” that clearly informs Lepore book. At the same time, they chide her for what they regard as significant omissions. These critical essays invite further consideration of how best to write a fully inclusive (and therefore dramatically reconfigured) national narrative