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1. Sweet corn growth, yield, and lignocellulose decomposition on Excelzyme-treated Histosol

Author

Prawito P., Handayani M., Herman W., and Puspaningsih N.N.T.

Subjects
Environmental sciences, GE1-350
Abstract

Histosol is a sub-optimal soil containing high lignocellulose resulting in its lower decomposition rate. To improve Histosol decomposition, the application of Excelzyme was used. The purposes of this study were (1) to determine the decomposition rate of lignocellulose of histosol treated with Excelzyme; and (2) to determine the best dosage of Excelzyme for the growth and yield of sweet corn. The study has been conducted at the University of Bengkulu Research Station, from July to November 2021. This experiment was designed in randomized completely block design, involving dosages of Excelzyme i.e. E0 = 0 ml plot-1; E1 = 1,000 ml plot-1; E2 = 1,500 ml plot-1; and E3 = 2,000 ml plot-1. The plot size was 2 m x 3 m, and all treatments were repeated 3 times. Results of the study showed that Excelzyme application affects the rate of histosol decomposition showed by decreasing lignin, cellulose, and hemicellulose compared with the untreated Histosol. The best dosage of Excelzyme was 2.000 ml plot-1 that decrease lignin, cellulose, and hemicellulose content by 32.69 %, 24,43 %, and 5.80 % in the upper 0 – 15 cm respectively compared to the untreated Histosol. While in the 15 – 30 cm depth, lignin, cellulose, and hemicellulose decrease by 25,92 %, 21.11 %, and 7.05 % respectively, compared with the untreated histosol. The application of Excelzyme of various dosages was not significantly affecting soil pH at both depths as well as sweet corn growth and yield.

Published
2023
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5. Effects of Corn Stalks Ash as A Substitution Material of Cement Due to the Concrete Strength of Rigid Pavement

Author

Mildawati, Roza, Puri, Anas, and Handayani, M. Zaky

Subjects
Cement Substitution, Compressive Strength, Flexural Strength, Rigid Pavement, Optimum Content
Abstract

Cement is an adhesive material for concrete mixtures in addition to water, fine and coarse aggregates. One of the main ingredients of cement is silica (SiO2) which is originated from the earth's crust. Silica is also available in plants such as corn stalks. This research is aimed to utilize the corn stalk ash (CSA) as an alternative substitution for some cement in concrete for the rigid pavement of road construction. According to the Indonesian standard, the flexural tensile strength should be exceeded at least 4.5 MPa. The flexural tensile strength has also a correlation due to compressive strength. The concrete materials consisted of the coarse aggregate (river crushed stone) from Kampar River and Danau Bingkuang sands from Kampar District of Riau Province, and Portland Composite Cement from Semen Padang. The CSA was made by burning the dried corn stalks in a steel cylinder can over 24 hours. The content of CSA was varied by 0%, 5%, 7% and 9%. The compressive strength design of concrete was 31,3 MPa. Testing procedures were based on the Indonesian Standard for concrete. The tested specimens have consisted of cube specimens (150 mm x 150 mm x 150 mm) for compressive tests, and beam specimens (150 mm x 150 mm x 600 mm) for flexural strength tests. All specimens were tested on 28 days-age. The results show that CSA can be used as a partial substitution of cement in concrete. The addition of CSA tends to increase the compressive strength of concrete instead of its flexural tensile strength. The optimum content of CSA was 7% and resulted in an 8.0% and 6.9% increase in compressive and flexural tensile strength due to design respectively. Compressive and flexural tensile strength fulfilled the standard. Flexural tensile strength is obtained by 15% of the compressive strength. Cornstalk ash can be used as a substitution of cement for rigid pavement concrete. It can reduce the utilization of cement and will be potentially cost efficiency.

Published
2022
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15. CHARACTERISATION OF GRAPHENE DERIVED FROM COCONUT SHELLS: IMPACT OF AMMONIA DOPING AND THE SONICATION METHOD

Author

Giyanto, Jon Affi, Gunawarman, Handayani Murni, Yetri Yuli, and Rohmat Nur

Subjects
coconut shell, carbonisation, pyrolysis, sonication, graphene nanosheet, Clay industries. Ceramics. Glass, TP785-869
Abstract

Coconut shells, a type of biomass, are a potential carbon source. They can be transformed into charcoal via carbonisation, and then can be synthesised into graphene. As an eco-friendly and cost-effective material, it can be used to produce Graphene Nanosheets (GNS). The process involves roasting the coconut shells at 220 °C and pyrolysing at 600 °C to obtain pure GNS or GNS-NH3 doped. The material is then sieved using a 200-mesh sieve and sonicated. The graphene's morphology is examined using SEM-EDX tests and characterised by XRD and FTIR. Its electrical conductivity stability is assessed by measuring the current strength at voltages of 40, 44, 48, 51, and 55 Volts with a current of 17.6 Amperes. Graphene demonstrates relative stability, with a slight decrease in electron loss with small current increases, which helps control the electron mobility. This is due to graphene's capacity to store and slowly release electrons. The stability of graphene's conductivity aids in electric current conduction and extends the lifespan of graphene-based batteries. However, graphene exhibits better electrical conductivity at 40 V than at 55 V. The literature suggests that increasing the voltage results in decreased electrical conductivity. This is because GNS is not yet fully capable of controlling the electron mobility at higher voltages, making it less stable in accommodating the electrical conductivity.

Published
2024
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21. Deletion Polymorphism of Angiotensin-Converting Enzyme Gene Is Associated with Low Muscle Mass in Elderly People in Jakarta, Indonesia

Author

Handayani, M. D. N., Sadewa Ahmad Hamim, Farmawati, A., and Rochmah, W.

Subjects
Aged, 80 and over, Male, Aging, Sarcopenia, Polymorphism, Genetic, Base Sequence, Genotype, Articles, Middle Aged, Peptidyl-Dipeptidase A, Cross-Sectional Studies, Indonesia, Humans, Female, Aged, Sequence Deletion
Abstract

Decline in muscle mass due to aging is a growing public health problem as it contributes to a decreased capacity for independent living among elderly people. A clear understanding of genetic factors is important, as it is known that angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism affects muscle mass, although the findings are frequently heterogeneous. This study was conducted to determine the association between ACE I/D polymorphism and muscle mass in elderly people. A total of 130 elderly people were recruited from nursing homes in Jakarta. Anthropometric components affecting the muscle mass were examined. Cross-sectional analyses were performed to compare data using t-test, ANOVA and ANCOVA, and linear regression. Genotyping of the ACE I/D polymorphisms was performed by PCR methods, and muscle mass was evaluated by BIA. Genotype distribution counts II 65.38%, ID 13.85%, and DD 20.77% were not consistent with the Hardy–Weinberg equilibrium (χ(2) = 22.2, df = 2; p < 0.01). Individuals with the DD genotype showed lower muscle mass that was significantly different compared to the muscle mass in individuals with the II/ID genotype (II 16.14 ± 0.38, ID 15.71 ± 0.59; DD 13.95 ± 0.61 kg), after adjusting for % fat as a covariate. The linear regression analysis showed that age, gender, weight, height, nutritional status, protein content, and waist, hip, and calf circumference were significant contributors to muscle mass. In the multivariate analysis, adjusted age and gender significantly correlated with muscle mass, with r(2) = 0.98, by the likelihood ratio test (p < 0.01). The genotype variability accounted for 2.65% of the DD genotype. This study showed that in an elderly population in Jakarta, the DD genotype was associated with low muscle mass. This result suggests the role of nutritional status as a potential mediator in the association between ACE gene and muscle mass.

Published
2018

23. Development of graphene and graphene quantum dots toward biomedical engineering applications: A review

Author

Handayani Murni, Hendrik, Abbas Aumber, Anshori Isa, Mulyawan Rahmat, Satriawan Ardianto, Shalannanda Wervyan, Setianingsih Casi, Pingak Charline Tiara Rehuellah, Zahro Qurriyatus, Rurisa Ayu Candra Sekar, Setiawan Iwan, Khotimah Khusnul, Sunnardianto Gagus Ketut, and Rahmayanti Yosephin Dewiani

Subjects
graphene, graphene quantum dots, synthesis, biomedical engineering, Technology, Chemical technology, TP1-1185, Physical and theoretical chemistry, QD450-801
Published
2023
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38. In-situ Hydrothermal Synthesis of Nickel Nanoparticle/Reduced Graphene Oxides as Catalyst on CO2 Methanation.

Author

Krisnandi, Y. K., Abdullah, I., Prabawanta, I. B. G., and Handayani, M.

Subjects
METHANATION, HYDROXYL group, GRAPHENE oxide, HYDROTHERMAL synthesis, NICKEL, SCANNING electron microscopes, NANOPARTICLES, CATALYSTS
Abstract

In this study, Nickel nanoparticles/reduced graphene oxide was successfully prepared through an in-situ hydrothermal process by applying graphene oxide as a precursor that was applied as a catalyst for converting CO2 into CH4. NiNPs/rGO were characterized using UV-Vis spectrophotometer, Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy-Dispersive X-Ray Spectroscopy (EDS). The characterization of the UV-Vis spectrophotometer shows NiNPs/rGO gave absorption at 260 nm which indicates red shifting from GO absorption peak (230 nm). FTIR spectra of NiNPs/rGO shows a decreasing in absorbance from the peaks of the oxygen-containing group (i.e. carboxylic and hydroxyl group) previously contained in the GO, moreover disappearance of the absorption peak at 1736 cm−1 (C=O) in NiNPs/rGO also indicates that reduction process from GO into rGO has been successfully carried out. The construction of Nickel nanoparticles on the surface of the rGO was proven from the results of EDX (% mass) shows the presence of C (21.84 %), O (5.58 %), and Ni (72.58 %) on the surface of NiNPs (30 %)/rGO. In its application as catalysts, the NiNPs (30 %)/rGO catalysts have shown a good activity in the process of CO2 methanation (i.e. CO2 conversion into CH4). Initial catalytic test had been done to evaluate the effect of reaction temperature on CO2 methanation using NiNPs (30 %)/rGO as catalyst. The catalytic test result shows that catalys could produce methane as the main product with highest value of 17.63 % at 673 K. [ABSTRACT FROM AUTHOR]

Published
2020
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41. Upaya Meningkatkan Pemahaman Konsep Matematika Melalui Model Pembelajaran Problem Solving Pada Siswa Kelas Viiid SMP N I Kasihan

Author

Handayani, M. D. (ML), Handayani, M. D. (ML), Wardani, W. W. (Wahyu), Handayani, M. D. (ML), Handayani, M. D. (ML), and Wardani, W. W. (Wahyu)

Abstract

Penelitian ini bertujuan untuk meningkatkan pemahaman konsep dalam pembelajaran matematika siswa kelas VIII D SMP N 1 Kasihan setelah mengikuti kegiatan pembelajaran matematika dengan menggunakan model pembelajaran Problem Solving pada pokok bahasan Kubus dan Balok. Metode penelitian yang digunakan adalah metode penelitian tindakan kelas, yaitu suatu upaya untuk mencermati kegiatan belajar secara kolaboratif berupa sebuah tindakan yang sengaja dimunculkan dan terjadi dalam sebuah kelas. Subyek penelitian ini adalah siswa kelas VIII D dengan jumlah 30 siswa. Teknik pengumpulan data yang digunakan adalah observasi, tes, catatan lapangan dan dokumentasi. Teknik anaslisis data yang digunakan adalah deskriptif kualitatif yaitu menganalisis data observasi, catatan lapangan dan dokumentasi, sedangkan deskriptif kuatitatif yaitu menganalisis data observasi dan tes. Hasil penelitian ini adalah pembelajaran matematika dengan model pembelajaran Problem Solving dilakukan melalui enam fase yaitu menyajikan permasalahan, mengidentifikasi pola atau aturan yang disajikan, mengekplorasi, menginvestigasi, menduga dan menemukan solusi, dengan tingkat keterlaksanaan 95,83% (kriteria tinggi) di siklus I dan 100% (kriteria tinggi) di siklus II sehingga dapat meningkatkan pemahaman konsep matematika siswa dari Prasiklus 44,44 (kriteria kurang), meningkat pada siklus I 72,25 (kriteria baik) dan meningkat pada siklus II 85,08 (kriteria baik sekali).

Published
2015

49. Iron and boron removal from sodium silicate using complexation methods.

Author

Wahyuningsih, S., Suharty, N. S., Pramono, E., Ramelan, A. H., Sasongko, B., Dewi, A. O. T., Hidayat, R., Sulistyono, E., Handayani, M., Firdiyono, F., Amal, M. Ikhlasul, Herbirowo, Satrio, Hasbi, M. Yunan, Lestari, Yulinda, Annur, Dhyah, and Malau, Daniel Panghihutan

Subjects
SOLUBLE glass, COMPLEXATION reactions, BORON, IRON, SILICA, SOLAR cells, ATOMIC absorption spectroscopy
Abstract

Silica purification of other materials is needed to improve the purity of silica that suitable for solar cells requirement. The silica is obtained from roasting of sand minerals in sodium silicate form. Iron (Fe) and boron (B) are an impurity that must be separated to obtain high pure silica. Separation of Fe and B used complexation methods. Chitosan-EDTA is used to remove Fe component and curcumin is used to remove B component. The elemental analysis with Atomic Absorption Spectrophotometer (AAS) showed the amount of Fe in sodium silicate decreased after binding to Chitosan EDTA. The contact duration between sodium silicate and chitosan-EDTA at baseline did not affect the results. Then the removal of B from sodium silicate using curcumin was done under basic conditions. B-Curcumin complexes were known from the wavelength number shifts of O-H, C-O, and C = O vibrational in the IR spectrum. The results showed that the optimum concentration of curcumin for removal B was 2 × 10−7 M. [ABSTRACT FROM AUTHOR]

Published
2018
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50. Protein enrichment in instant pudding with fish protein hydrolysate (FPH) from trash fish

Author

Salampessy Randi B.S., Yuniarti Tatty, Handayani Melur Gitawigati, and Nurbani Siti Zachro

Subjects
Microbiology, QR1-502, Physiology, QP1-981, Zoology, QL1-991
Abstract

Fish Protein Hydrolysate (FPH) from trash fish is a product derived from fish through the process of protein hydrolysis, into smaller protein, including peptides and eventually amino acids. The FPH is used to enhance the characteristics of various food products, such as to amino acid profiles, and improve nutritional content. The purpose of this study was to increase protein levels and flavor intensity profiling instant pudding by adding FPH. The design experimental utilized the Complete Random Design (RAL) method. The study evaluated several parameters related to pudding quality: Hedonic Quality, Taste Intensity and Proximate, used ANOVA (Analysis of Variance) to compare means among different treatments (pudding with varying levels of FPH). The protein content of instant pudding ranged between 7.68-8.77%, higher than comercial instan pudding. The protein content of ready-to-eat pudding ranged from 1.84-2.28%, The highest acceptance rate observed was 5% for pudding with added FPH. Taste intensity tests revealed that adding FPH at higher concentrations resulted in intensified burning, fishy, and bitter aromas. The highest protein content was achieved with the addition of 15% FPH. The study provides valuable insights into how FPH impacts instant pudding.

Published
2024
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