bluuebunny/crossref_metadata_2025 huggingface dataset:
A culturally responsive teaching approach and ethnochemistry integration of Tegal culture for developing chemistry students’ critical thinking skills in acid-based learning
Authors: Rahmawati Y , Baeti H R , Ridwan A , Suhartono S , Rafiuddin R
Published: December 2019

The aim of this study was to develop students’ critical thinking skills through a Culturally Responsive Teaching (CRT) approach and ethnochemistry of Tegal culture. The teaching approach focused on exploring the culture and local wisdom in Tegal Culture, especially in Acid-Base such as the Nginang, Moci, and Jamasan traditions from chemistry perspectives integrated into CRT. The study employed a teaching model consisting of five phases; self-identification, cultural understanding, collaboration, critical reflections, and transformative construction. The study involved 35 year 11 students from a secondary school in Balapulang Tegal. A qualitative methodology approach was employed using observation, interviews, a critical thinking test, and reflective journals as data collection methods. The results show that the integration of ethnochemistry in a CRT approach engaged students in developing their critical thinking skills by developing a conclusion, making connections, conceptual understanding, and interpretation with the critical thinking skills test which shows 40% of students reached level 3 (Satisfactory). In addition to the students engaging in the cultural identity empowerment, meaningful chemistry learning experiences, and team work, the students were challenged in developing their critical thinking skills.
Analysis of water quality and hotel liquid waste in Ubud Region, Gianyar
Authors: Pratiwi A E , Sumadewi N L U
Published: December 2019

A research on the analysis of water quality and hotel liquid waste in Ubud sub-district, Gianyar-Bali has been conducted. The analysis of raw water quality was done to discover whether the raw water can be appropriately classified as clean water. The parameters used in analyzing the raw water are its bacteriological and hardness level. Analysis on the quality of liquid waste was done discover whether the hotel liquid waste can still be categorized align with the government standard in the disposal to the surrounding environment. Based on the result of hotel raw water analysis, five samples have aligned with the clean water standard, which is possible to categorized as clean water; while for the analysis of hotel liquid waste, the parameters used are turbidity, pH, BOD, COD and bacteriological test. The analysis shows that four hotels have exceeded the reasonable level of waste, where scheduled surveillance is required in keeping the environment away from waste disposal.
Chemistry students’ cognitive structures in oxidation-reduction, through an 8E learning cycle
Authors: Rahmawati Y , Ridwan A , Faustine S , Auliyani C N , Kartika I R , Rafiuddin R
Published: December 2019

The purpose of this study was to analyse students’ cognitive structure in the concept of oxidation reduction by employing an 8E learning cycle model. 32 students in year-10 were participated in the study. Data was collected by a drawing and writing technique demonstrated through student worksheets, interviews, observations, and a reflective journal. The 8E learning cycle, which consist of engage, explore, e-search, elaborate, exchange, extend, evaluate and explain stages, was applied to the process. Data analysis consisted of data reduction, data presentation, and a conclusion. Students’ cognitive structures were divided into three categories, namely; an understanding, misconception and no understanding. Categories of understanding were found in the concept of redox, oxidizing agents and acid-base nomenclature, and transitions. Students’ misconceptions of categories were found in the redox applications and polyatomic. Students faced challenges in understanding the oxidation number and binary nomenclature. The results show that misconceptions were decreased through the implementation of the 8E learning cycle. The 8E Learning cycle also has implications for students’ critical thinking, collaboration, and empathy communication skills.
Problem-based learning tools oriented of green chemistry in reaction rate concept
Authors: Fauziah N , Andayani Y , Hakim A
Published: December 2019

The aims of the study to produce and discover the quality of problem-based learning tools oriented to green chemistry in the reaction rate concept. Learning tools consists of the syllabus, lesson plan, student worksheet, modules, and test instruments. This research and development adapted Nieveens model which consisted of four stages: preliminary research, prototyping stage, summative evaluation, and reflection and documentation. The quality of the learning tools developed was measured through the analysis of validity and practicality. Product validity assessment used validation questionnaires distributed to experts, the data obtained were analyzed by using the content validity formula. Practicality used response questionnaires assessed by teachers and students, and the implementation of learning was analyzed by using a percentage of practicality. This study resulted in the average of content validity being 0,67 categorized valid. The practicality percentage of each aspect is 90,87%, 80,06%, and 80,56% categorized highly practical. The concluded that learning tools developed fulfills the criteria for developing quality products that are valid and practical.
Variations of binding, washing, and concentration of imidazole on purification of recombinant Fim-C Protein Salmonella typhi with Ni-NTA Resin
Authors: Nurjayadi M , Afrizal R , Hardianto D , Agustini K
Published: December 2019

Typhoid fever is an endemic disease in Indonesia. Prevention of typhoid fever can be done by administering vaccines. It is known that one of the raw materials for vaccines is a recombinant protein. This study aims to obtain information on the optimum conditions for purification of Salmonella typhi Fim-C recombinant protein with Ni-NTA resin as vaccine raw material. The three main stages of the purification process in this study were binding, washing, and elution of S. typhi Fim-C recombinant proteins. The binding and washing variations of recombinant proteins were carried out twice, four times and six times, while the elution process was carried out at imidazole concentrations of 200 mM, 250 mM, and 300 mM. Purification with a binding process four and six times gave almost the same intensity of S. typhi Fim-C protein bands. Whereas protein was elution at an imidazole concentration of 300 mM showed higher band instability. The results of characterization using SDS-PAGE and analysis using software ImageJ gel analysis showed that the longer the incubation time and the repetition of the binding process, the more protein bound to the resin. Furthermore, the more washing processes are obtained the purer proteins. Based on the data obtained it can be concluded that the purification of the S. typhi Fim-C recombinant protein was optimum at a four-time binding process, six times washing and a 300 mM imidazole concentration. These results are expected to be the basis for recombinant protein refining on a pilot scale and industry scale in better vaccine preparation.
Make it real: Simulation of 3D molecules using Augmented Reality in chemical bonding topic
Authors: Fitriani E , Suhartono S , Mugiarti I
Published: December 2019

The chemical bonding is one of the crucial topics in chemistry as it becomes a basic concept to comprehend other topics. Unfortunately, it is difficult for students to understand because it is at the submicroscopic level. This study proposes a way to comprehend that topic by developing a simulation of 3D molecules using Augmented Reality (AR). The data was collected by questionnaire. This study was used ADDIE procedure to develop the product. From the results of this study, it can be concluded that the Augmented Reality learning media has a very good quality and is worthy of being used as a supporting media in chemical learning activities in the chemical bond topic.
Constructing a simple electrolyte conductivity meter for chemistry learning
Authors: Hafimiyah D , Sukmawardani Y , Sundari C D D , Farida I
Published: December 2019

This research is based on the idea of the need for an innovative experimental learning media in the study of physical chemistry on electrolyte solutions conductivity concept. Through Research and Development method with the stages of analysis, design and development, a simple electrolyte conductivity measurement device has been produced. Based on the results of the research, the product was obtained in the form of an electrolyte solution conductivity measuring device that equipped with a user guidebook and an experimental worksheet of the electrolyte solution conductivity measurement. The electrolyte solution conductivity device is designed to measure the conductivity of an electrolyte solution. This measurement device is able to compare the conductivity value of fruit juices, vegetable juices and isotonic drinks quantitatively based on Kohlrausch’s law with simple and easy devices and materials. The validation result shows that the product is valid. The product was tested to chemistry education students using a feasibility test instrument. The result shows that the average of the value of the feasibility test is 93.85%. These results indicate that the constructed electrolyte conductivity meter is feasible to be used.
Development of mobile learning on acid and base to improve student performance
Authors: Cahyana U , Yusmaniar Y , Zahari P A
Published: December 2019

The aim of this research is to (1) make a Mobile Media Learning on Acid and Base and to determine the quality of the media produced, (2) determine the feasibility of the media used in learning process. The subjects of this research were students of 54 Senior High School Jakarta, 42 Senior High School Jakarta, and 7 chemistry teachers. The research was conducted from January to May 2018. The method used in this research is Design-Based Research. The steps performed in this research are: (1) needs analysis, (2) developing mobile learning, (3) validation test of mobile learning media, (4) media testing by students and small scale of teachers, (5) media trials by students and teachers on a large scale. The results obtained from expert validation tests, small class trials, large class trials, and effectiveness of the media, it can be concluded that the mobile media learning developed in this research is good enough to use in the learning process. The n-gain value obtained from the effectiveness test is 0.76 which can be categorized as high effectiveness, based on the Paired t-test the Tcount value is 28.048. The paired t-test value is Tcount>Ttable (2.03), so it can be concluded that there is a significant difference between pre-test score and post-test score. That difference means that there is improvement in students average score after using the mobile media learning.
Development of mobile game base learning on buffer solution to improve student performance
Authors: Cahyana U , Paristiowati M , Pratiwi W E , Zahari P A
Published: December 2019

This study aims to develop innovative learning media that is Mobile Learning and know the quality of media produced and know the feasibility of media to be used in learning on buffer solution. This research was conducted at 107 Senior High School Jakarta and 42 Senior High School Jakarta starting in January 2018 until May 2018. The research method used is Design-Based Research which includes 4 stages, namely: (1) needs analysis, (2) development of mobile learning media, (3) Feasibility and trial test. Mobile learning media that generates an app on Android-based smartphones (smartphone) called “ChemBuff” is 167 MB compatible on Android devices up to v.7.1 Nougat with features such as material, video and educational features about the solution buffer. Based on the feasibility test results and the small scale and large scale effectiveness tests, it can be concluded that the mobile learning media is feasible and effective. The result of the effectiveness test shows that there is a very significant difference between the pre-test and post-test value as well as an increase in the average learning outcomes of learners after using mobile learning media buffer solution. The resulting media test can improve student learning outcomes.
Synthesis of silicalite-1 zeolite using silica from elephant grass (Pennisetum purpureum)
Authors: Sundari C D D , Setiadji S , Andriani A , Sumiyanto E , Ivansyah A L
Published: December 2019

Silicalite-1 is a type of zeolite with no aluminum content and is hydrophobic. This zeolite can be synthesized from various types of silica. Elephant grass (Pennisetum purpureum) is one of the potential agricultural wastes that has a fairly high silica content that can be used for zeolite synthesis. In this study, silicalite-1 zeolite was synthesized using silica extracted from elephant grass and tetrapropylammonium bromide (TPABr) templates. Silica samples extracted from elephant grass have 71.91% amorphous SiO2 content. Silicalite-1 zeolite was synthesized with molar ratio of 1SiO2 : 0.527TPABr : 0.395Na2O : 98.45 H2O, using hyrothermal method at 180°C for 24 hours in a stainless steel-teflon lined autoclave. The resulting silicalite-1 samples were confirmed by X-Ray Diffraction (XRD) and showed 2θ which was typical for silicalite-1 i.e. 8.02°, 8.93°, 23.09°, and 23.98°. The results of Scanning Electron Microscopy (SEM) show that silicalite-1 zeolite has hexagonal crystals with 43.36 µm size as a result of the calculation using the Schrerrer method.
Identification of glibenclamide in antidiabetic jamu by high performace liquid chromatography method: Study in Purwokerto, Indonesia
Authors: Utami P I , Firman D , Djalil A D
Published: December 2019

Adulteration of synthetic pharmaceutical drugs in jamu is prohibited by law in Indonesia. Glibenclamide is one of the drugs commonly added to antidiabetic jamu. The purpose of this study was to obtain a valid high performance liquid chromatography (HPLC) method for qualitative and quantitative analysis of glibenclamide in antidiabetic jamu. HPLC separation was carried out with a Kromasil 100 C18 column (150 x 4.6 mm i.d, 5 μm particle size) using methanol: water (75:25) v/v as the mobile phase at a flow rate of 0.5 mL/min, UV detection was set at 301 nm. There was no potential interference from other compounds at the glibenclamide retention time (retention time of 5.234 ± 0.056 minutes). The method has good linearity (r = 0.9936) in the range 10-50 µg/mL. The detection limit of the method was 6.21 µg/mL while the quantitation limit was 20,71 µg/mL. The relative standard deviation (RSD) of intraday precision was 0.85%. The average recovery using standard addition method was 100.63 ± 13.71%. The application of the HPLC method for the analysis of five antidiabetic jamu samples obtained from the market in Purwokerto showed that glibenclamide was detected in one sample with a level of 1.88 ± 0.25 µg/g.
Formulation of facial cleansing gels using aloe vera as natural surfactant
Authors: Wulandini R , Irwansyah F S , Windayani N
Published: December 2019

This study aims to make facial wash gel made from Aloe vera as a natural surfactant. The design based research experimental method used includes the phytochemical screening analysis of samples of A. vera extract, making A. vera gel with the addition of carbomer 960 to the aloe extract solution with a percentage of 0.5%, 0.7% and 2%, selection of essential oils according to the needs of facial skin. Furthermore, making Aloe gel as a facial wash by adding carbomer 960 with a percentage of 0.5%, 0.7%, 2% then add triethanolamine to alkalinize the A. vera extract to form a stable gel according to the characteristics of the Indonesian national standard (SNI 2588:2017). This facial wash utilizes secondary metabolites contained in A. vera. The results showed that A. vera extract used positively contained flavonoid, triterpenoid, saponin and polyphenol compounds. The best formulation of facial wash gel has been successfully obtained from the addition of carbomer 960 with a percentage of 0.7%, triethanolamine eight drops, moringa seed oil 1ml, virgin coconut oil 1ml, one drop of lavender oil, whey kefir five drops, and natural E 2 capsules. The organoleptic results of A. vera gel as facial wash include having an aroma following the added essence, soft texture, gel form, cloudy white color, feeling relaxed or cold when applied to facial skin, and without foam having a pH of 5 according to SNI.
The effect of concentration and temperature on the activities of Polyethylene Oxide (PEO) as iron corrosion inhibitor in electrolyte solution of NaCl
Authors: Sudiarti T , Silviayanadewi A Y , Supriadin A
Published: December 2019

Internal corrosion in the piping system is a serious problem. The use of corrosion inhibitors for corrosion control in piping systems is a practical and cost-effective method. Many polymers have been reported to be used as an inhibitor corrosion. However, there was little attention to the research of Polyethylene Oxide (PEO) as a corrosion inhibitor in NaCl medium. The purpose of this study was to determine the corrosion inhibition activity of polymeric compounds of polyethylene oxide against ferrous metals in 1% NaCl electrolyte solution. The study of Polyethylene Oxide (PEO) activity as a corrosion inhibitor in 1% NaCl electrolyte solution was carried out by the Wheel Test method with variations in concentration and temperature. The surface analysis of iron by SEM (Scanning Electron Microscopy). The results showed that polyethylene oxide (PEO) had the optimum inhibitory activity at a concentration of 16 ppm, with inhibition efficiency of 80.15% at 25°C. Polyethylene Oxide has adsorption properties which are in accordance with the Langmuir adsorption isotherm with free adsorption energy of -21.385 kJ / mol. The results of the surface analysis by Scanning Electron Microscopy (SEM) showed that polyethylene oxide could inhibit corrosion rates with iron surfaces that had fewer pores than without inhibitors.
Chemical changes coconut oil in different fermentation during long time storage
Authors: Janurianti N M D , Sudiarta I W , Situmeang Y P
Published: December 2019

This research aims to know the old fermentation influence the chemical changes during storage on coconut oil. Coconut oil is made with fermented pineapple extract as much as 15%. Coconut oil characteristics compared with the standard National Indonesia No. 01-2902-1999. This research was carried out in the laboratory of Food Analysis Faculty of Agriculture Warmadewa University. This study is a Randomized Design with factorial experiment complete consisting of two factors, namely: factor I, long fermentation that consists of 3 levels, namely 12 hours, 24 hours and 36 hours. Factor II, long storage that consists of 4 levels, namely 0, 1, 2 and 3 weeks. The observed variables against the coconut oil include objective observations i.e. water content, free fatty acids, peroxide, levels of dirt and acid number. The characteristics of coconut oil during storage tend to change but still meet Indonesian National Standard No. 01-2902-1999. From the results of research on the long fermentation 12% with prolonged storage 0 weeks gives the characteristics of the best oils than any other treatment that is the average value of water content, the level of dirt, free fatty acids, peroxide and acid number respectively i.e. 0.17%, 1.56%, 0.53%, 1.45% and 2.20%. During the storage of chemical changes tend to occur on coconut oil. The value of the average water content, the level of dirt, free fatty acids, peroxide and acid number highest obtained on treatment of fermentation 36 hours and long storage of 3 weeks in a row with a value of 0.50%, 3.70%, 0.85%, 2.51% and 4.38%.
Preparation and photocatalytic activity of hematite from iron sand modified ZnO for indigo carmine degradation
Authors: Lubis S , Maulana I , Sheilatina S , Mahyuni L
Published: December 2019

Modification of hematite (α-Fe2O3) with ZnO to produce ZnO/α-Fe2O3 composites by sol gel method and their photocatalytic activity testing on the degradation of indigo carmine (IC) dye has been done. The hematite was extracted from iron sand using hydrochloric acid and precipitated using aqueous ammonia. The ZnO/α-Fe2O3 composites were prepared with the mole ratio of ZnO to α-Fe2O3 1:1, 1:5 and 5:1. XRD pattern analysis showed that the average crystallite size of ZnO/α-Fe2O3 composites were greater than that of α-Fe2O3. The result of photocatalytic activity test showed that composite with the mole ratio of ZnO to α-Fe2O3 1:5 has the highest photocatalytic activity under the optimized conditions, with the maximum degradation efficiency of IC are 91.75 % and 93.18 % under UV light and sunlight irradiation, respectively. These highest of photocatalytic activity was reached at the initial pH of dye solution = 1, photocatalyst dosage of 300 mg, initial dye concentration 15 ppm and irradiation time 120 minutes under UV light and 90 minutes under sunlight irradiation.
Effect of blanching pre-treatment on colour and anthocyanin of dried slice purple sweet potato (Ipomoea batatas L)
Authors: Mahmudatussa’adah A , Patriasih R , Maulani R R , Nurani A S
Published: December 2019

Purple sweet potato (Ipomoea batatas L) contains many acylated anthocyanins which are beneficial for human health. Purple sweet potato roots are easily damaged due to the high water and nutrient content. To extend the shelf life of purple sweet potatoes can be done by a drying process. The drying process can affect the colour and amount of anthocyanin. The purpose of this study was to analyse the effect of blanching on colour and the amount of anthocyanin of dried slice purple sweet potato. The blanching method studied was steam blanching with a temperature of 70°C-80°C and blanch with boiling water 90°C – 98°C for 2 minutes. To measure the amount of anthocyanin by the pH difference method and measure colour using the chromameter. The results showed that the steam blanching technique produced a higher colour and amount of anthocyanin of dried chips purple sweet potato compared to blanching boiling water. This is because Anthocyanin dissolves in water. The conclusion is to get the colour and the relatively high amount of anthocyanin in dried pieces of purple sweet potato can be done by steam blanching. The implication to prevent browning process when making dried slice purple sweet potato can do steam blanching.
Screening of the drought tolerant phosphate solubilizing bacteria in dissolving P-inorganic
Authors: Susilowati L E , Kusumo B H , Arifin Z
Published: December 2019

The drought tolerant phosphate solubilizing bacteria is needed to dissolve inorganic phosphate (P) which is usually low in the availability at dry land. This study is aimed to obtain a combination of drought tolerant phosphate solubilizing bacteria which has high potential in dissolving P-inorganic. An experimental study which has 4 treatments of bacterial combinations has been conducted in a laboratory. The first treatment was the combination between Pseudomonas azotoformans (A) and Acinetobacter baumannii (B). The second treatment was the combination of A and Bacillus paramycoides (C). The third treatment was B and C, then the fourth treatment was A, B, and C. The potential of the bacterial combination in dissolving P-inorganic was measured qualitatively using phosphate solubilizing index (PSI) on pikovskaya solid medium. While, the potential of the bacterial combination in dissolving P-inorganic was measured quantitatively by measuring dissolved P using the ascorbic acid method in pikovskaya liquid medium containing 0.5% Ca3(PO4)2. The results showed that the combination of those three bacteria (A B and C) has the best potential to dissolve P-inorganic compared to other combinations. In addition, the three bacteria combination also resulted in the highest dissolved P with 0.29% potential dissolution of the total Ca3(PO4)2 contained in the pikovskaya liquid medium, followed by combination of B and C (0.19%), and A and C (0.18%), respectively. Thus, before the combination of these three bacteria is applied in soil, it is needed further experiment of the potential of the bacteria in dissolving soil P-inorganic.
Antioxidant activity from ethanol extract of kupa leaves (Syzygium polycephalum(Miq.) Merr& L. M.Perry) using DPPH (2,2-diphenyl-1-picrylhydrazil) method
Authors: Perdana F , Martiani I , Dhanti D
Published: December 2019

Kupa is one of the endemic plants from Indonesia belong to guava family (Myrtaceae). This research conducted to determine antioxidant activity of kupa leaves (Syzygiumpolycephalum (Miq.) Merr& L. M. Perry) ethanol extract. Extraction of kupa leaves was carried out by maceration method using ethanol 96%. The antioxidant activity test was done qualitatively and quantitatively. The qualitative antioxidant test was carried out by Thin Layer Chromatography (TLC) using mobile phase chloroform: methanol: formic acid (8: 2: 1) and DPPH 0.2% spotting appearance. Quantitative testing of antioxidant was carried out using DPPH (2,2-diphenyl-1-picrylhydrazil) assays. The TLC test results showed yellow spot on the DPPH with Rf value 0.381. Kupa leaves ethanol extract had the lowest IC50 of DPPH scavenging activity 10.327 ppm which was a very strong antioxidant.
Formulation and evaluation of body splash from Java preanger Arabica coffee (Coffea arabica L.) oil
Authors: Handayani R , Auliasari N , Oktaviany T K , Hindun S , Sriarumtias F F
Published: December 2019

Java preanger Arabica coffee (Coffea arabica L.) is a distinctive coffee from Priangan having special property as a natural fragrance. The essential oil in java preanger arabica coffee (Coffea arabica L.) beans contains Abhexon, Furaneol, Sotolon, and Pentandion. The purpose of this study was to find out the percentage of the coffee extract concentration contributes to a good fragrance and how to formulate a safe and stable body splash preparation. The research began with material collection, determination, coffee roasting production, soxletation with ether solvents, dosage formulations with one percent, three percent, and six percent concentrations and evaluations including organoleptic test, pH, viscosity, quality test of the body splash preparations (spreadability, endurance, spot, and adhesion tests), irritation test, sharpness test and preference test. The results showed that the formula with the three percent Java preanger Arabica coffee (Coffea arabica L.) oil concentration was a safe, stable and the scent was favored because it was not too strong and left no stains.
Formulation and evaluation fast disintegrating film salbutamol sulfat using HPMC E15
Authors: Nurhabibah N , Sriarumtias F F , Fauziah S , Auliasari N , Hindun S
Published: December 2019

The aim of the study was to formulate and evaluate Fast Disintegrating Film salbutamol sulfate with HPMC E15 polymer using a solvent casting method. FDF salbutamol sulphate preparations with variations oaaf HPMC E15 polymer concentration (F1 = 30%, F2 = 40%, F3 = 50% and F4 = 60%). Film of salbutamol sulphate was evaluated organoleptic, thickness, uniformity of weight, folding endurance, PH surface, moisture loss, moisture uptake and in vitro disintegration time. The result showed that film of salbutamol sulphate produce flexible and semi-transparent films. Evaluation results of thickness, weight, folding endurance, surface pH, moisture loss and moisture uptake and film disintegration time of all formulas met the requirements, except the uniformity of weight at F4, time of disintegration of F1, F2, F3 and F4 because high concentration of polymer and not added surfactant and superdisintegrant.
Graphite surface profile with different polishing treatment
Authors: Budiman B A , Sambegoro P , Halimah P N
Published: December 2019

Graphite is a fascinating material to study in nanotechnology. Surface profile and roughness of the graphite are some of the most important parameters to determine many physical and mechanical behaviors including friction or bonding condition. To acquire certain surface profile, mechanical polishing treatment is one of the easiest ways that can be applied. In this work, graphite is polished by three different grades of sandpapers (P800, P400, and P220) and cellulose-based paper. The surface properties are observed by a laser microscope and various surface roughness parameters were quantified. The sequential polishing process employed in this work is able to modify the surface roughness and might improve the physical properties. This work sheds light on the importance of the mechanical surface treatment on graphite.
Characteristics composite of wood powder, coconut fiber and green mussel shell for electric motorcycle brake pads
Authors: Kholil A , Dwiyati S T , Sugiharto A , Sugita I W
Published: December 2019

The brake pads mostly consist of asbestos fiber with polymeric matrix and other ingredients. The use of asbestos fiber is been avoided due to its carcinogenic nature. The main purpose of this study was to determine characteristics of the composite made from wood powder, coconut fiber, and green mussel shell that will be used for electric motorcycle brake pads. Composites were made with three variations. Specimen A consisted of 30% wood powder, 10% coconut fiber, 10% green mussel shell and 50% polyester resin. Specimen B consisted of 20% wood powder, 20% coconut fiber, 10% green mussel shell and 50% polyester resin. Specimen C consists of 10% wood powder, 30% coconut fiber, 10% green mussel shell and 50% polyester resin. All specimens were characterized by hardness testing according to ASTM E 92 by Vickers FV-300e test equipment. Each specimen was tested three times and taken data-average. Decomposition testing used TGA NETZSCH TG 209F3. The results of the characterization were compared with commercial brake pads. Specimens with the closest characteristics to the commercial brakes were shown by specimens A with 33.1 VHN and decomposition temperature 90 °C.
Analysis of jacket pile failure at breasting dolphin pile on berthing dolphin system
Authors: Hakim B L , Subawi H , Taptajani D S , Ikhwana A , Chandrahadinata D
Published: December 2019

The study evaluated the structural damage of the jetty pile jacket due to the impact load within operation days. The pile jackets on breasting dolphin (BD) were destroyed in front of pneumatic floating fender or leaning back direction. It observed that the failure was due to an impact load perpendicular to the pile and shear load between the floating fender and the pile jacket. The polyolefin material for pile jacket is not designed to hold any impact load from pneumatic fender vertically during docking. The pile jacket was installed to protect against to corrosion attack between tidal and splash zone. While the coal barge is docking on the jetty, the floating fender will crash and push the pile jacket by impact load at about 13.88 ton.m and swing press perpendicular to the breasting dolphin pile or shear load vertically. The installation of rack fender may practically protect the breasting dolphin pile and to back up currently pneumatically floating fender and the jacket pile.
Analysis of determining deliverability test and transient pressure in the PW-02 Well of Alpha Fields by using Ecrin software
Authors: Wijayanti P , Said L , Singh P J
Published: December 2019

Quantitative analysis of reservoir properties in a well is determined by transient pressure analysis. Transient pressure according to its type consists of Pressure Build up and Pressure Draw Down. this analysis provides an overview of the characteristics of a reservoir. This analysis includes the process of determining drainage area, shape, heterogeneity, porosity, average pressure, skin, permeability, and distance from a reservoir to boundary or flow discontinuities. This test is to determine the ability of gas production in the PW-02 Well, carried out by using the Modified Isochronal test method. This test aims to determine the productivity of a potential (Absolute Open flow). Transient pressure test on PW-02 Well using the Pressure Build up Test (Type Curve Pressure Derivative) method, it is found that the well model is Vertical well and the reservoir model is Two porosity PSS. While the boundary model obtained is Rectangle. Then, the data obtained in the form of positive skin is 1.46, the permeability is 62.5 mD and the reservoir pressure is 2529.32 psia. Based on the analysis obtained Absolute Open Flow Potential (AOFP) is 117406 mscf/D. While the deliverability test value obtained is 117413 mscf/D with n value of 0.825.
Effect of Salt quenching on the microstructures and mechanical properties of AISI 1045 steel
Authors: Basori I , Pratiwi W D , Dwiyati S T
Published: December 2019

Steel has a very important role in the industrial applications, especially for the manufacture of automotive components such as gear. In its applications, gear undergoes the compressive and friction loads, so that in the manufacturing process, materials with high hardness and wear resistance are needed. One method to increase steel hardness is by quenching process. In this research, quenching process will be carried out on AISI 1045 steel using pure water and the salt solution as the cooling medium. The austenization process was conducted at a temperature of 850 ° C with the holding time of 15 and 30 minutes. The samples were then quenched at the cooling medium of salt solution with concentration of 0, 10 and 23%. The results showed that the quenching process on AISI 1045 steel promotes the phase transformation from mixture of ferrite and pearlite to be martensite. The increase of austenization holding time and salt concentration level resulted in higher martensite intensity and hardness. In contrast, the increase of austenization holding time and salt concentration level resulted in lower toughness.
Laboratory study on the addition of banana midrib and kwikseal as LCM to the physical properties of mud at high temperature
Authors: Pauhesti P , Hamid A , Anggoro C A
Published: December 2019

Drilling mud is a very important role in drilling operations, start over drilling until reaches the depth of the intended. In the importance of drilling mud, therefore there should have an analysis of potential problems that might happen in the process of the drilling, one of them is about the lost circulation. One of the ways to overcome the loss of drilling mud is to use LCM (Lost Circulation Material). In this study used Kwikseal and Banana Midrib as an ingredient LCM. Both of these materials into the fibrous material categories that have a little stiff texture so as inhibit the lost circulation in a way in the forced entry into the cracks and can clog the pores and close it to be able to cope with the onset of the lost circulation problem. In research was done three times experiment with the additional kwikseal and adding banana midrib. The results of the research are expected us to know how much composition kwikseal or banana midrib to be added to the mud and effective to overcome lost circulation. From the overall results obtained that the LCM Kwikseal has a better effect than the LCM Banana Midrib to reduce fluid loss at temperatures above 250°F.
Application hall plot method for surveillance waterflood in oil reservoir
Authors: Dalimunthe Y K , Hanifah A , Setiati R
Published: December 2019

Pattern X is one of the patterns in Field Z which is 60 km west of Prabumulih, South Sumatra, where the full-scale waterflood is implemented. In general, the pattern used is an irregular inverted 5-spot where there are six production wells namely Z-091, Z-098, Z-110, Z-157, Z-195, and Z-233 and one injection well namely Z-227. Waterflood is a secondary recovery method by injecting water into the reservoir. Waterflood surveillance analysis was carried out to determine the conditions around the production and injection wells during waterflood. Surveillance analysis is used as a measure of success in waterflood activities. One of the methods that used is the Hall Plot method. It is obtained a slope which moves upward where displacement is moved normally or stable. However, over time there is an increase in the slope of the tilt where skin changes occur. In fact, the slope that occurs due to the installation of Multilayer Packer is used to adjust the desired injection rate. In the end, the injection results have no problems and run stable.
Application of pressure build up analysis for reservoir oil
Authors: Sunardi A H , Setiati R , Samsol S
Published: December 2019

The well analysed in this paper is A-1 well, T field, located approximately 90 km north of Bali. Reservoir in this field is gas reservoir with sandstone rock formation, one of the problems of A-1 well is sand problem. Due to the sand problem in well A-1, well test analysis must be done first, to see if there is any damage to the formation if the flow rate is increased. Identification of formation damage in a well can be done by doing Pressure Build up test. The method used is pressure build up test by Horner method with Sapphire software v.3.20. The determination of deliverability test was conducted by back pressure test. Given the results of the analysis, the permeability value remains, the value of the skin and reservoir pressure decreased. From the results of the tests, there were no significant changes, indicating no formation damage. The results of the deliverability tests decrease, due to decreased reservoir pressure. Since there is no formation damage, the flow rate can still be increased up to 30% of AOFP.
Comparison between import and local product of Koma material for hardness and microstructure
Authors: Tjahjanti P H , Wicaksono A D , Akbar A , Ganda A N F
Published: December 2019

Koma material is one of the wire cutting machine part from PT. X in Indonesia, which has a function as a wire straightening device that will be processed or cut. This material is made from white cast iron and is obtained from imports. Never tried to make the local product. The aim of the research is making Koma material from white cast iron. The method is used to make Koma material which has a quality similar to imported products. The prepared material later will be tested using hardness testing and optical microscope measurement for observing its microstructure. The results are compared with Koma imported products show that Koma material of imported products has a higher hardness than local products, due to the differences content in chemical elements in the white cast iron.
Size dependencies on melting of Gold nanoparticle: A Molecular Dynamics study
Authors: Fahdiran R , Handoko E , Sugihartono I
Published: December 2019

We study the size dependencies on melting of Gold nanoparticle. The nanoparticles are built with different sizes and heated up with same temperature gradient from room temperature up to 1400 K. The trajectories of the atoms are investigated based on Molecular Dynamics (MD) simulation. Pressure evolution as a function of time shows the oscillation pattern as in the case of thermal induced melting. Analysis based on structure factor combined with Common Neighbour Analysis (CNA) indicated the properties of melting depends on nanoparticle sizes.
Fourier Transformed Infrared (FTIR) spectroscopy for analysis of cholesteryl acrylate liquid crystall-indium tin oxide composites
Authors: Afrizal A , Rahman A , Florencia F V , Jati L
Published: December 2019

The aim of this research is to synthesis composites and polymerizations of cholesteryl acrylate with dopan of Indium Tin Oxide (ITO). Composite of cholesteryl acrylate-ITO was made by using casting solution technique at 75°C for 30 minutes. Monomer cholesteryl acrylate and ITO have succeeded in becoming a composite with blending process in variations concentrations of ITO. The photopolymerization process by UV curing method with variation of UV lamp power that is 10, 25, 40 and 55 watt. Analysis of functional group with FTIR showed vibration of In-OH bond with C-O at wave number 1056,99 cm−1. Other peak in wave number 2929,87 cm−1 for vibration of groups in bond C-H in vinyl, wave number at 2860,01 cm−1 for vibration bond of C-H alyfatic. Spectrum FTIR of ITO showed at wave numbers: 437,84; 487,99; 534,28; 619,15 cm−1. Therefore, after photopolymerizations process, peak at 2100 cm−1 has disappeared in spectrum FTIR of Cholesteryl acrylate which showed molecule of cholesteryl acrylate had polymerized. Conductivity of composite of cholesteryl acrylate-ITO was determined using by LCR meter. In general conductivity value and permittivity of composite of cholesteryl acrylate-ITO increase with the increasing of the concentration of dopan ITO was added to the composites. SEM images of composite of cholesteryl acrylate-ITO show that pores of cholesteryl acrylate had been filled by ITO particles. The SEM-EDX data show that the content of the elements contained in the composite cholesteryl acrylate-ITO are: C 76.91%, O 3.13% and In 5.13%. The value conductivity (σ) of composite of cholesteryl acrylate-ITO is 4.078 x 10−10S/m, therefore polymer of cholesteryl acrylate-ITO of σ is 11.2 x 10−10S/m.
Temperature dependence of the mechanical behavior of ZnO-Na2O-P2O5 glasses
Authors: Budi A S , Mujadi M
Published: December 2019

In this research, we investigate the mechanical behaviour of zinc sodium phosphate glass system with the various concentration of chromium oxide doped. The glass system was synthesized using the melt quenching technique. The concentration of chromium oxide varying from 0.5% to 2.5%. The ultrasonic wave velocities have been determined as functions of temperature from 273 K and 333 K. The transit time data and density are used to determine all of the mechanical behavior for these glasses, we found that the mechanical behaviour of the glass system decrease as the Cr2O3 content increase, which indicates a weakening of the binding energy in the network.
Structure, microstructure, electrical transport mechanism and magnetoresistance in La0.8Ag0.2MnO3
Authors: Kurniawan B , Sahara N A , Imadudin A , Rahman I N , Razaq D S , Munazat D R
Published: December 2019

Bulk polycrystalline sample of La0.8Ag0.2MnO3 has been successfully synthesized by the sol gel method. Structural, morphology, electrical properties and magnetoresistance has been investigated. Refinement results from XRD at room temperature showed a single-phase material with a rhombohedral crystal structure and R-3c space group. Electrical transport showed by comparison of experimental data with theoretical model, the sample undergo a metal-insulator transition at TM-I accompanying the ferromagnetic-paramagnetic transition. Data for temperature dependence of resistivity has been fitted using the formula ρ(T) = ρ

FM

f + (1 − f)ρ

PM
, ρ

PM
is resistivity of the ferromagnetic region, ρPM is resistivity of the paramagnetic region and f is the volume fraction of ferromagnetic phase. Result of fitted data is in good agreement with experimental data. MR measurements in the range of magnetic field 0-1 T, measurements were carried out at temperatures of 15 K, 100 K, 200 K and 285 K, the results showed a decrease in resistivity.
Specific capacitance and impedance of electrodeposited polyaniline, polypyrrole and polyaniline/polypyrrole composite films
Authors: Budi S , Deswara R D , Mahmud A , Paristiowati M , Handoko E , Sugihartono I , Fahdiran R
Published: December 2019

The aim of this work was to prepare polyaniline, polypyrrole and polyaniline/polypyrrole composite films using electrodeposition techniques. Films were examined using a Fourier transform infrared spectrometer, which confirmed the formation of the single polymers and their composite. Morphological analysis was carried out using a scanning electron microscope and showed the flat and highly compact deposit of polypyrrole/polyaniline composites, whose morphological characteristics varied from those of the single polymers, which had porous deposits. Electrochemical properties of the materials were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Impedance values showed that polyaniline had the best charge transfer and the polyaniline/polypyrrole composite had the highest specific capacitance value, which was 530.96 F/g. This result indicates that the electrodeposited films can find application for electrode in capacitive deionization systems.
The I-V characteristics of hydrothermal growth ZnO nanorods
Authors: Budi A S , Sari I Y , Nuryadi R , Bakri F , Muliyati D
Published: December 2019

This study aims to analyze the conductivity of ZnO nanorods grown by using the hydrothermal method. We use the I-V characteristic test to determine the conductivity. In this research, the process of making samples of ZnO nanorods was carried out in two stages: preparing the seed layer and then growing ZnO nanorods using the hydrothermal method. After testing the characteristics of using SEM, the resulting crystal structure of ZnO nanorods is hexagonal wurtzite with the direction of growing perpendicular to the substrate. Besides, the resulting I-V characteristics indicate a physical phenomenon that occurs at a temperature variation of ≥ 190°C which means a peak. While the details of phenomena still need to be elaborated. Besides, a gas effect test was also conducted which showed that the sensor was at a maximum working temperature of 190°C with an input voltage of 8 volts and reached a gas sensitivity at 220°C.
Mud gas play
Authors: Burhannudinnur M
Published: December 2019

The presence of methane gas seepage in the mud volcano proves the existence of gas associated with over pressured zone in the subsurface. The analysis of C isotope on samples of methane gas seepage of mud volcano show the gas is thermogenic methane at the level of thermal maturity that is equivalent to the peak of petroleum formation. The mud of mud volcano extruded from overpressures zone beneath is predicted to have high gas storage capacity. The objectives of this paper are to define capacity of the mud of mud volcano system as a potential reservoir gas and its role in petroleum system. Isothermal absorption test is performed to answer the storage capacity of the mud of Kesongo and Lusi mud volcanoes system. Seismic data and velocity data show over pressured mud zone as chaotic zone with low velocity anomaly distributed crossing the reflector layer as chamber. The gas storage capacity of the mud based on adsorption test at the temperature of 65-degree Celsius ranges from 812 scf/ton up to 3,217 scf/ton shows it has capacity of gas reservoir. The adsorbed gas in over pressured mud shows different mechanism with that of the conventional reservoir. Adsorbed gas in over pressured mud can be proposed as unconventional gas reservoirs with new alternative hydrocarbon play: mudgas-play (MGP). Mud-gas-play is defined as the accumulated gas trapped in over pressured zone. Gas accumulations tend to be concentrated in the upper part of over pressured zone.
Index group optimization based on automatic clustering using K-Means genetic algorithm
Authors: Multazam M T , Dijaya R , Devi N M S
Published: December 2019

E-prints UMSIDA is a repository of student and lecturer publication documents at the Muhammadiyah University of Sidoarjo (UMSIDA). The collection of documents is still random and the search can only detect from the title keywords. The increasing culture of writing and research makes it possible for more and more documents as literature. Documents in E-prints are grouped by subject provided by the repository manager and grouped by the admin who uploaded the document. Automatic document grouping can be done by grouping documents based on the contents of the document using the Information Retrieval (IR) approach. The retrieval process is carried out by document processing with tokenisation to obtain data tokens, the data tokens are processed through a stemming process to obtain the stem value of each word. The stem value is processed using the indexing process and word stem to get sentence indexes through the weighting process. The index results stored in the database become document variables that are the features or characteristics of each document. The index of all documents is grouped through Automatic Clustering technique using K-Means Genetic Algorithm.