scholarly journals KAJIAN PENGARUH MATERIAL PROPERTIS DOMAIN BATUAN DASAR TERHADAP KESTABILAN LERENG PADA NIKEL LATERIT DI SITE POMALAA , SULAWESI TENGGARA, PT ANTAM Tbk

2020 ◽  
Vol 1 (1) ◽  
pp. 453-462
Author(s):  
Mutiara Andini ◽  
Niki Rahma Rizkita ◽  
Pherto Rimos ◽  
Febri E. Prihasto ◽  
Ahmad R. Trilaksana ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Key Words ◽  
Safety Factor ◽  
Material Properties ◽  
Friction Angle ◽  
Probability Of Failure ◽  
Mining Operations ◽  
Average Value ◽  
Simulation Results ◽  
Proper Material

ABSTRAK Untuk mendukung kegiatan operasional penambangan, perlu dilakukan pembuatan kajian geoteknik yang bertujuan sebagai rencana awal desain lereng tambang maupun mengevaluasi kestabilan lereng pada saat kegiatan penambangan berlangsung. Untuk pembuatan kajian geoteknik di Site Pomalaa, dilakukan pengambilan 15 sampel untuk masing-masing domain (Hazburgit, Dunit, Serpentinit dan Peridotit) yang dibagi menjadi 5 sampel limonit, 5 sample saprolit dan 5 sampel bedrock. Selanjutnya, sampel tersebut dilakukan pengujian di laboratorium untuk mendapatakan nilai material properties. Material propertis limonit pada setiap domain  memiliki rentang nilai kohesi 31,22 kN/m2- 40,49 kN/m2, sudut geser dalam 31,30o-37,36o, berat jenis basah 11,56 kN/m2-12,89 kN/m2, UCS 0,11Mpa – 0,59 Mpa.Sedangkan nilai material propertis pada saprolit memiliki rentang nilai kohesi 31,22 kN/m2-39,18 kN/m2, sudut geser dalam 34,71o-39,11o, berat jenis basah 10,86 kN/m2-13,52 kN/m2, UCS 0,19Mpa – 0,29 MPa. Material propertis tersebut selanjutnya digunakan sebagai parameter dalam melakukan analisis kestabilan lereng dengan mengeluarkan nilai faktor keamanan (FK) dan probability of failure (PoF). Pada kajian ini dilakukan simulasi dengan 4 pendekatan : (a) Pertama, menganalisis lereng dengan domain geologi tunggal, (b)Kedua, menganalisis lereng dengan menggabungkan 2 domain geologi yang berbeda, (c) Ketiga, menganalisis lereng dengan menggabungkan 3 domain geologi yang berbeda, (d) Menganalisis lereng dengan menggabungkan 4 domain geologi yang berbeda. Hasil simulasi dengan menggunakan 4 pendekatan tersebut menunjukkan nilai rata-rata FK limonit secara berturut sebesar 1.72, 1.71,1.73, dan 1.73 . Sedangkan nilai FK saprolit secara berturut sebesar 1.74, 1.78 , 1.75 dan  1.74. Rata-rata probability of failure pada simulasi ini dibawah 1%. Dari hasil simulasi dapat dilihat bahwa nilai faktor keamanan dari hasil simulasi beberapa material menunjukkan nilai yang konsisten, sehingga dapat dikatakan bahwa nilai material propertis nikel laterit pada batuan dasar yang berbeda cenderung sama (homogen), oleh karena itu pengambilan sampel geoteknik di site pomalaa tidak sensitif terhadap domain batuan. Key words: Domain Batuan Dasar, Kohesi, Sudut Geser Dalam, Berat Jenis Basah, UCS, Faktor Keamanan, Probability of Failure.  ABSTRACT Concerning mining operations activities, geotechnical analysis should be carried out with the aim of planning the initial design of slope and evaluating the stability of the slope during mining activities. For making geotechnical studies at the Pomalaa Site, 15 samples were taken for each domain (Hazburgit, Dunit, Serpentinit and Peridotit) which were allocated into 5 samples for limonite, 5 samples for saprolite and 5 samples for bedrock. Furthermore, the sample is tested in a laboratory to obtain the value of material properties. Limonite property material in each domain has a range of cohesion values of 31.22 kN / m2-40.49 kN / m2, friction angle at 31.30o-37.36o, wet density 11.56 kN / m2-12.89 kN / m2, UCS 0.11Mpa - 0.59 Mpa. While the value of proper material in saprolite has a range of cohesion values of 31.22 kN / m2-39.18 kN / m2, shear angle in 34.71o-39.11o, wet specific gravity 10.86 kN / m2-13.52 kN / m2, UCS 0.19Mpa - 0.29 Mpa. The property material is then used as a parameter input to obtain slope stability analysis by issuing factor of safety (FK) and probability of failure (PoF) values ). In this case a simulation was conducted to 4 approaches: (a) First, analyzing slopes with a single geological domain, (b) Second, analyzing slopes by combining 2 different geological domains, (c) Third, analyzing slopes by combining 3 different geological domains , (d) Analyze slopes by combining 4 different geological domains. The simulation results using the 4 approaches show the average value of FK limonite which are 1.72, 1.71.1.73, and 1.73 respectively. While FK saprolite values were 1.74, 1.78, 1.75 and 1.74 respectively. The average probability of failure in this simulation is below 1%. From the simulation results it can be seen that the value of the safety factor from the simulation results of several materials shows a consistent value, so it can be said that the material value of laterite nickel properties in different bedrock tends to be the same (homogeneous), therefore geotechnical sampling at the Pomalaa site is not sensitive to the rock domain. Key words: Host Rock Domain, Cohesion, Friction angle, Wet Specific Gravity, UCS, Safety Factor, Probability of Failure.

EFEKTIVITAS PENERAPAN METODE CONTEXTUAL TEACHING AND LEARNING TERHADAP PENINGKATAN HASIL BELAJAR SISWA DALAM MATA PELAJARAN ILMU PENGETAHUAN ALAM (IPA) KHUSUS DALAM MATERI SIFAT-SIFAT CAHAYA

2018 ◽  
Vol 2 (3) ◽  
pp. 329
Author(s):  
Ni Wayan Rusniati
Keyword(s):  
Learning Outcomes ◽  
Learning Process ◽  
Material Properties ◽  
Teaching And Learning ◽  
Science Learning ◽  
Learning Model ◽  
Learning Material ◽  
Average Value ◽  
Lecture Method ◽  
Contextual Teaching

The process and student learning outcomes in science learning material properties of light is a problem faced by class IV SD Negeri 3 Mengwi. Student activity and learning outcomes have not been maximized because the teacher delivered science learning materials using the lecture method. This is the background of the researchers to conduct research with the aim of improving the process and learning outcomes of science with material properties of light with learning models Contextual Teaching and Learning. This research is a type of classroom action research conducted in SD Negeri 3 Mengwi. The subjects of this study were fourth grade students, amounting to 27 students consisting of 14 female students and 13 male students. The implementation of this study used 2 cycles. Instruments used to collect data are observation sheets, interviews, documentation and test questions. The results of this study indicate that science learning outcomes with material properties of light using the Contextual Teaching and Learning model in SD Negeri 3 Mengwi have increased in two cycles with quite satisfactory values. There was an increase in learning outcomes from cycle 1 an average value of 68.51 to 75.37 in cycle 2. In addition, there was an increase in the learning process of students in science learning carried out by teachers using the Contextual Teaching and Learning model. Keywords: Learning process, learning outcomes, Contextual Teaching and Learning

Transfers with a rendezvous lasting no more than one orbit between close near-circular coplanar orbits

2020 ◽  
pp. 82-93
Author(s):  
Aleksandr F. BRAGAZIN ◽  
Alexey V. USKOV
Keyword(s):  
Key Words ◽  
Relative Velocity ◽  
Free Parameter ◽  
Space Station ◽  
Characteristic Velocity ◽  
Orbital Station ◽  
Orbit Transfer ◽  
Simulation Results ◽  
The Moment ◽  
Phase Differences

Consideration has been given to orbit transfers involving spacecraft rendezvous which belong to a class of coplanar non-intersecting near-circular orbits of a spacecraft and a space station. The duration of the transfer is assumed to be limited by one orbit. The feasibility of a rendezvous using an optimal two-burn orbit-to-orbit transfer is studied. To determine a single free parameter of the transfer, i.e. the time of its start, ensuring a rendezvous at a given time or at a given velocity at the end of transfer, appropriate equations have been obtained To implement in the guidance algorithms optimal three-burn correction programs are proposed to achieve a rendezvous at a given time with a specified relative velocity at the moment of spacecraft contact. A range of phase differences at the start of maneuvering is determined, within which the characteristic velocity of the rendezvous is equal to the minimum characteristic velocity of the orbit-to-orbit transfer. The paper presents simulation results for “quick" rendezvous profiles that use the proposed programs. Key words: spacecraft, orbital station, “quick” rendezvous, orbit transfer, rendezvous program.

scholarly journals Development of Elastoplastic-Damage Model of AlFeSi Phase for Aluminum Alloy 6061

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 954
Author(s):  
Hailong Wang ◽  
Wenping Deng ◽  
Tao Zhang ◽  
Jianhua Yao ◽  
Sujuan Wang
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Material Properties ◽  
Damage Model ◽  
Scratch Test ◽  
Aluminum Alloy 6061 ◽  
Ultra Precision ◽  
Simulation Results ◽  
Alloy 6061 ◽  
Elastoplastic Damage

Material properties affect the surface finishing in ultra-precision diamond cutting (UPDC), especially for aluminum alloy 6061 (Al6061) in which the cutting-induced temperature rise generates different types of precipitates on the machined surface. The precipitates generation not only changes the material properties but also induces imperfections on the generated surface, therefore increasing surface roughness for Al6061 in UPDC. To investigate precipitate effect so as to make a more precise control for the surface quality of the diamond turned Al6061, it is necessary to confirm the compositions and material properties of the precipitates. Previous studies have indicated that the major precipitate that induces scratch marks on the diamond turned Al6061 is an AlFeSi phase with the composition of Al86.1Fe8.3Si5.6. Therefore, in this paper, to study the material properties of the AlFeSi phase and its influences on ultra-precision machining of Al6061, an elastoplastic-damage model is proposed to build an elastoplastic constitutive model and a damage failure constitutive model of Al86.1Fe8.3Si5.6. By integrating finite element (FE) simulation and JMatPro, an efficient method is proposed to confirm the physical and thermophysical properties, temperature-phase transition characteristics, as well as the stress–strain curves of Al86.1Fe8.3Si5.6. Based on the developed elastoplastic-damage parameters of Al86.1Fe8.3Si5.6, FE simulations of the scratch test for Al86.1Fe8.3Si5.6 are conducted to verify the developed elastoplastic-damage model. Al86.1Fe8.3Si5.6 is prepared and scratch test experiments are carried out to compare with the simulation results, which indicated that, the simulation results agree well with those from scratch tests and the deviation of the scratch force in X-axis direction is less than 6.5%.

FEMLIB: An Object-Oriented Framework for Optimization and Simulation

1995 ◽  
Author(s):  
Michael M. Tiller ◽  
Jonathan A. Dantzig
Keyword(s):  
Material Properties ◽  
Object Oriented ◽  
The Finite Element Method ◽  
Simulation And Optimization ◽  
Gradient Based ◽  
Level Problem ◽  
Simulation Results ◽  
Optimization And Simulation ◽  
High Level ◽  
Simulation Parameters

Abstract In this paper we discuss the design of an object-oriented framework for simulation and optimization. Although oriented around high-level problem solving, the framework defines several classes of problems and includes concrete implementations of common algorithms for solving these problems. Simulations are run by combining these algorithms, as needed, for a particular problem. Included in this framework is the capability to compute the sensitivity of simulation results to the different simulation parameters (e.g. material properties, boundary conditions, etc). This sensitivity information is valuable in performing optimization because it allows the use of gradient-based optimization algorithms. Also included in the system are many useful abstractions and implementations related to the finite element method.

scholarly journals Penerapan Model Pembelajaran Multilierasi Informasi Untuk Meningkatkan Pemahaman Konsep Jual Beli

JURNAL IQRA ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 42-55
Author(s):  
Budi Febriyanto ◽  
Ari Yanto
Keyword(s):  
Elementary School ◽  
Action Research ◽  
Social Studies ◽  
Key Words ◽  
Average Score ◽  
Class Iii ◽  
Learning Models ◽  
Average Value ◽  
The Third ◽  
Model Understanding

This article aimed to improve the understanding of the concept of purchase and sale in class III Elementary School of Mekarjaya III through the application of information multiliterasi learning models. This research was  classroom action research. This research was conducted in three cycles. The results showed that the percentage of classical completeness in the first cycle has average 63.2 with the percentage of classical completeness which was 48.5%. In the second cycle the average score of students were 70 with the percentage of classical completeness  63.6%. In the third cycle the average value of students were  81.2 with the percentage of classical completeness 87.9%. Then it can be concluded that the application of the multiliteration learning model of information on social studies subjects has success to increase the understanding of the concept purchase and sale in class III Elementary School of Mekarjaya III District Majalengka. Key words: Multiliteration Information Model, Understanding of Purchase and Sale

scholarly journals Field and Laboratory-based Approach for the Determination of Friction Angle of Geological Discontinuities of Malaysian Granites

2011 ◽  
Vol 28 (2) ◽  
pp. 151 ◽  
Author(s):  
R. A Ghani ◽  
T. L Goh ◽  
A. M Hariri ◽  
Y. N Baizura
Keyword(s):  
Friction Angle ◽  
Roughness Coefficient ◽  
Average Value ◽  
Peak Friction Angle ◽  
Maximum Value ◽  
Wide Range ◽  
Discontinuity Surfaces ◽  
Geological Discontinuities ◽  
Range Of Values

The basic friction angle, Φb for artificially sawn discontinuity planes for fresh granite, as determined by tilt testing, has an average value of 30º. For the natural rough discontinuity surfaces, a wide range of values have been determined for the peak friction angle, Φpeak ranging from 47º to a maximum value of 80º, depending on the joint roughness coefficient (JRC). The average values of the friction angles for the different degrees of roughness were as follows: JRC 2–4 = 58°; JRC 6–8 = 60°; JRC 8–10 = 47°; JRC 12–14 = 60°; JRC 14–16 = 71° ; JRC 18–20 = 80°.

scholarly journals Analisis Perancangan Frame Gokart dari Pengaruh Pembebanan dengan Menggunakan CAD Solidworks 2016

Jurnal METTEK ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Angga Restu Pahlawan ◽  
Rizal Hanifi ◽  
Aa Santosa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Safety Factor ◽  
Frame Structure ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Aisi 1045 ◽  
Steel Aisi ◽  
Simulation Results ◽  
Manual Calculation

Frame adalah salah satu komponen yang sangat penting dalam sebuah kendaraan, yang berfungsi sebagai penopang penumpang, mesin, suspensi, sistem kelistrikan dan lain-lain. Melihat fungsi dari frame sangat penting, maka dalam merancang sebuah frame harus diperhitungkan dengan baik. Banyak sekali jenis pengujian yang sering dipakai dalam perancangan sebuah struktur frame, salah satunya adalah digunakannya metode komputasi dengan menggunakan metode Finite Element Analysis (FEA). Tujuan dari penelitian ini adalah untuk mengetahui distribusi tegangan, regangan, displacement, dan safety factor dari hasil pembebanan statis pada frame gokar. Struktur frame didesain dan dianalisis menggunakan software Solidworks 2016. Material yang digunakan frame adalah baja AISI 1045 hollow tube 273,2 mm, dengan menggunakan pembebanan pengendara sebesar 50 kg dan 70 kg. Hasil dari perhitungan manual didapatkan tegangan maksimum sebesar 4,735  107 N/m2, sedangkan dari simulasi didapatkan sebesar 4,516  107 N/m2. Regangan maksimum didapatkan dari perhitungan manual sebesar 2,310  10-4. Displacement maksimum didapatkan dari perhitungan manual sebesar 1,864  108 mm, sedangkan dari simulasi didapatkan sebesar 1,624  108 mm. Safety factor minimum didapatkan dari perhitungan manual sebesar 11,193, dan perhitungan simulasi didapatkan sebesar 11,736. The frame is one of the most important components in a vehicle, which functions as a support for passengers, engines, suspensions, electrical systems and others. Seeing the function of the frame is very important, so designing a frame must be taken into account well. There are many types of tests that are often used in the design of a frame structure, one of which is the use of computational methods using the Finite Element Analysis (FEA) method. The purpose of this study was to determine the distribution of stress, strain, displacement, and safety factor from the results of static loading on the kart frame. The frame structure was designed and analyzed using Solidworks 2016 software. The material used in the frame is steel AISI 1045 hollow tube 27  3,2 mm, using a rider load of 50 kg and 70 kg. The result of manual calculation shows that the maximum stress is 4,735  107 N/m2, while the simulation results are 4,516  107 N/m2. The maximum strain is obtained from manual calculation of 2,310  10-4. The maximum displacement is obtained from manual calculations of 1,864  108 mm, while the simulation results are 1,624  108 mm. The minimum safety factor obtained from manual calculation is 11,193, and the simulation calculation is 11,736.

Substantiation of probabilistic safety factors as a factor for optimizing the metal consumption of pipelines and the permissible operating pressure

2021 ◽  
pp. 364-371
Author(s):  
Юрий Григорьевич Матвиенко ◽  
Дмитрий Александрович Кузьмин ◽  
Владимир Васильевич Зацаринный ◽  
Максим Сергеевич Пугачев ◽  
Владимир Вячеславович Потапов
Keyword(s):  
Safety Factor ◽  
Probability Of Failure ◽  
Fracture Probability ◽  
Operating Pressure ◽  
Pipe Steels ◽  
Safety Factors ◽  
Metal Consumption ◽  
Load Variation ◽  
Coefficients Of Variation ◽  
The Given

Проведен анализ влияния коэффициентов вариации сопротивления материала разрушению и коэффициентов вариации нагрузки на вероятность разрушения и, следовательно, на коэффициенты запаса по характеристикам сопротивления материала разрушению при заданных показателях вероятности разрушения. Снижение неопределенности в условиях нагружения и повышение качества материала позволяют снизить коэффициенты запаса по пределу текучести и вязкости разрушения для заданных целевых показателей безопасности. На примере трубных сталей марок Ст 20 и 16ГС показана возможность снижения коэффициента запаса по пределу текучести до значений n = 1,45 при коэффициенте вариации нагрузки 0,1 и сохранении целевого показателя безопасности в терминах вероятности разрушения на уровне 10. Возможность снижения коэффициентов запаса по пределу текучести и вязкости разрушения при заданных целевых показателях безопасности в терминах вероятности разрушения позволяет оптимизировать металлоемкость и максимальные допустимые давления в эксплуатируемых трубопроводах. The analysis of the influence of the coefficients of variation of the material resistance and the coefficients of the load variation on the probability of failure as well as on the safety factors for the characteristics of the material resistance to failure has been done at given indicators of the probability of failure. Reducing uncertainty under loading conditions and improving material quality allow reducing the safety factors against fracture and collapse for given targets safety. Using the example of pipe steels of grades St 20 and 16GS, it seems possible to reduce the safety factor against collapse up to 1.45 with a load variation coefficient of 0.1 and maintaining the safety target in terms of the fracture probability at the level of 10. The possibility of reducing the safety factors against collapse and fracture at the given target safety indicators in terms of the fracture probability allows optimizing the metal consumption and the maximum allowable pressures in the operating pipelines.

scholarly journals EFFECT OF VARIATIONS OF BETA VULGARIS EXTRACTS ON MASKING THE BITTER TASTE OF MOMORDICA CHARANTIA EXTRACT SYRUP

2018 ◽  
Vol 10 (1) ◽  
pp. 159
Author(s):  
Sutriyo . ◽  
Raditya Iswandana ◽  
Elisa Nur Widiya
Keyword(s):  
Specific Gravity ◽  
Physical Properties ◽  
Beta Vulgaris ◽  
Sodium Benzoate ◽  
Bitter Taste ◽  
Momordica Charantia ◽  
The Other ◽  
Bitter Melon ◽  
Average Value

Objective: This study aimed to obtain a formula with an optimal sweetener concentration of beet extract that can cover the bitter taste of bitter melonand confer optimal physical properties on the syrup.Methods: The syrups were prepared by mixing bitter melon extract, sucrose, beet extract, sorbitol, sodium benzoate, strawberry essence, anddemineralized water. The control formula and formulas 1, 2, and 3 contained beet extract at concentrations of 0% and 10%, 15%, and 20%, respectively.All formulas were evaluated to determine their physical properties, stability, and bitterness. The bitterness was tested on 30 respondents, with databeing analyzed using Wilcoxon’s test on SPSS software.Results and Conclusion: Formula 3 with 20% beet extract was identified as the best formula for masking bitter taste because it had a significantlybetter average value than the other formulas (p<0.05) and the highest bitterless taste percentage (86.67%), with physical properties of a brownishblackcolor, odor of mixture of strawberry and dominant beet, a sweet and dominant beet taste, pH 5.46, and specific gravity of 1.228 g/mL.

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