Eva Oktavia Ningrum

Dr. Eva Oktavia Ningrum

orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2014 in Polymer
Verified
Journal Article
Closed access
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
YMYukiko Murakami
Yukiko Murakami
YOYasuhiro Ohfuka
Yasuhiro Ohfuka
TGTakehiko Gotoh
Takehiko Gotoh
SSShuji Sakohara
Shuji Sakohara

1 February 2015 in Polymer
Verified
Journal Article
Closed access
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
YOYasuhiro Ohfuka
Yasuhiro Ohfuka
TGTakehiko Gotoh
Takehiko Gotoh
SSShuji Sakohara
Shuji Sakohara

1 June 2019 in IOP Conference Series: Materials Science and Engineering
Verified
Conference Paper
Open access
PDF file
LPLily Pudjiastuti
Lily Pudjiastuti
TIT Iswanto
T Iswanto
AAA Altway
A Altway
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
TWTri Widjaja
Tri Widjaja
The effect of alkaline hydrogen peroxide (AHP) treatment on reducing lignin content in coffee pulp waste (CPW) was investigated to increase the digestibility and accessibility of cellulose during production of valuable products by enzymatic and biological process. Hydrogen peroxide (H2O2) at various concentrations (2.5, 5, and 7.5% (w/w of substrate)) was mixed into 10% (w/v) of CPW-NaOH solution at 35 °C for 24 h with pH 11.5. The concentration of lignocellulosic content was investigated. The characteristic of crystallinity index, functional groups, and surface morphology of CPW at before and after the treatment have been observed using XRD, FTIR, and SEM analysis, respectively. The results showed that the highest lignin removal was achieved at the addition of 7.5% H2O2which decreased from 16.85% to 8.5%. The concentration of cellulose and hemicellulose in CPW increased from 53% to 64% and 11% to 24%, respectively. The crystallinity index of AHP-treated CPW has increased from 30.83% to 42.08%. A surface morphological destruction on the CPW was getting worse as along with the increase of H2O2concentration. This would be useful to increase the porosity of biomass to give cellulose accessibility by enzyme for further processes.

28 June 2023 in International Journal of Technology
Verified
Journal Article
Closed access
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
IKIanatul Khoiroh
Ianatul Khoiroh
HNHanifah Inas Nastiti
Hanifah Inas Nastiti
RARyan Anindya Affan
Ryan Anindya Affan
AKAchmad Dwitama Karisma
Achmad Dwitama Karisma
SWSinung Widiyanto
Sinung Widiyanto
In the presented work, the formation of anodic oxide film on Ti-6Al-4V ELI (Extra Low Interstitial) alloy in 0.02 M trisodium phosphate (Na3PO4) electrolyte solution using various voltages were investigated. The color produced by the anodizing, the intensity of TiO2 content, the thickness of the oxide layer, and the corrosion rate were examined. It was obtained that the color appearance of Ti-6Al-4V ELI could be changed easily by altering the applied voltages. The higher the voltage applied in the anodizing process, the thicker the titanium oxide layer formed. The corrosion resistance analysis in a Simulated Body Fluid revealed that the non-anodized specimen showed a higher corrosion rate compared to the anodized specimen. The increase of oxide layer thickness leads to a significant decrease in corrosion rate and consequently increases the corrosion resistance. In addition, the anodized sample achieved the highest corrosion resistance at 15 V.

5 January 2023 in Journal of Chemical & Engineering Data
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Journal Article
Closed access
SASaidah Altway
Saidah Altway
ATArdila Hayu Tiwikrama
Ardila Hayu Tiwikrama
SRSerli Dwi Rahayu
Serli Dwi Rahayu
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
AAAli Altway
Ali Altway
LPLily Pudjiastuti
Lily Pudjiastuti

2 March 2020 in Indonesian Journal of Chemistry
Verified
Journal Article
Open access
PDF file
ENEva Oktavia Ningrum
Eva Oktavia Ningrum
APAgus Purwanto
Agus Purwanto
GRGaluh Chynintya Rosita
Galuh Chynintya Rosita
ABAsep Bagus
Asep Bagus
The properties of N-isopropylacrylamide copolymerized with N,N-dimethyl(acrylamidopropyl)ammonium propane sulfonate [poly(NIPAM-co-DMAAPS)] prepared with various monomer ratios such as transition temperature, molecular structure, viscosity were systematically investigated in water and Zn(NO3)2 solution. Poly(NIPAM-co-DMAAPS) in water and Zn(NO3)2 solution exhibited a phase transition with a lower critical solution temperature (LCST). The higher ratio of NIPAM monomer in poly(NIPAM-co-DMAAPS), the lower the LCST of the polymer. Furthermore, the transition temperature of poly(NIPAM-co-DMAAPS) with a lower NIPAM concentration were not confirmed both in water nor Zn(NO3)2 solution. The more increase the NIPAM concentration used in the preparation, the more increase the polymer viscosity. Moreover, the more increase the adsorption amount of ions onto the gel, the more increase the polymer transmittance as well.