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The leaf spring fabrication process, which consists of various processes, will result in susceptibility to atomic defects. Therefore, the identification of defects at the atomic scale through crystallography is very important in analyzing the slip mechanism to minimize the occurrence of leaf spring failure. This study aimed to analyze the causes of leaf spring failure by crystallography through an experimental approach. Residual stress testing was carried out using XRD with the sin 2 approach. The Sin 2 method uses angles -20°, -16°, -12°, -4°, 0°, 4°, 12°, 16°, 20°. Crystal orientation and texture were performed using MAUD 2.94 software to analyze the Miller index and crystallographic orientation distribution. Hardness test using Vickers micro with indentation points near and far from the leaf spring fracture surface. Leaf spring fracture morphology was tested using a DSLR camera and Scanning Electron Microscopy (SEM). The results of the residual stress analysis show a wavy elliptical curve indicating that the broken leaf spring has a shear stress and a stress gradient. The resulting residual stress has compressive properties with a value of -278.5±17.4 with the resulting crystal orientation consisting of miller index planes (110), (200), (211). The crystal orientation plane (200) has a characteristic texture that is oriented towards the Normal Direction (ND). Normal direction is indicated by a high probability value of 1.20. A high probability indicates that the leaf spring has material surface defects. The void is the beginning of the formation of crack initiation and becomes the center of stress concentration.

Environmental contamination poses a significant threat to the integrity of materials, including metals and composites. Addressing the degradation of natural fiber-reinforced polymer composites necessitates effective management strategies, particularly in mitigating UV and water-induced deterioration. This study explores the efficacy of Acrylated Epoxidized Soybean Oil (AESO) coating treatment following alkali treatment as a potential solution. Alkali treatment of Kapok fiber (KF) combined with polymer coating yielded composites exhibiting superior mechanical properties, particularly in tensile and flexural strength, following a 30-day aging period. Remarkably, the application of alkali and coating treatments led to a substantial enhancement in the mechanical strength of polyester composites, with the highest tensile strength recorded at 96.04 MPa. This represented a notable increase of 31.97% compared to untreated KF specimens. The observed enhancement in composite performance underscores the critical role of interfacial adhesion between fibers and the matrix, particularly under conditions of UV exposure and water immersion. Importantly, the study demonstrates that alkali treatment and polymer coating effectively mitigate degradation in Natural Fiber-Reinforced Polymer Composites, thereby offering promising avenues for enhancing their durability and longevity.

Natural and synthetic fibers have their own advantages and disadvantages. For this reason, hybridization was performed to combine the two fibers to get composite reinforcement with high mechanical properties. It is used to synergize the two fibers aiming to create a higher performance than that of natural fiber-reinforced composites. This study used carbon fiber and natural fiber namely Ceiba petandra fiber (CPF). Compared to hybrid and CPF reinforced composites, carbon fiber (CF)-reinforced composites had superior mechanical properties, especially in terms of tensile and flexural characteristics. However, it is more brittle and expensive. In contrast, CPF composite has the lowest tensile strength, flexural quality, and abundance. The optimal value was shown in CF/CPF reinforced hybrid composites with a composition of 15 % CF and 15 % CPF, with tensile and flexural strength reaching 130.16 ± 17.37 MPa and 98.53 ± 12.2 MPa. Hybrid composite improves the thermal stability of the composite. Findings showed that incorporating natural and synthetic fibers produced composite materials with acceptable and ideal mechanical performance.

Crystal defects can be identified through the crystallographic characteristics of crystal orientation (lattice), microstrain, and texture. Identification of crystal defects on the atomic scale through crystallography is very important in analyzing the mechanism of material properties due to the influence of dislocations. The slip mechanism is analyzed to minimize coil spring failure. This study aims to analyze the causes of coil spring failure based on crystallography. XRD testing was carried out for analysis of residual stress, crystal orientation, and texture using MAUD 2.94 version software. Hardness testing was carried out on the surface of the coil spring with locations near and far from the fracture using micro Vickers. The macro fracture morphology was analyzed using a DSLR camera and the micro fracture morphology was analyzed using SEM. The XRD result shows that the coil spring material has a tensile residual stress value of "202.4 ± 15.9 MPa" with the resulting crystal orientation showing the hkl (100), (200), (211), (200) fields. The plane (200) has a texture characteristic that is oriented towards the Rolling direction along the spring axis. Texture oriented towards Rolling Direction can be shown with a maximum probability value of 1.191. A high probability will have an impact on the presence of material surface defects. Surface defects are indicated by the presence of pit corrosion on micro and macro fracture morphology observations. The pit corrosion defects that occur in the failed coil springs are the beginning of the formation of crack initiation and cause stress concentration. The stress concentration will increase with loading and cause crack propagation.

The focus of today’s machining industry is on how to maintain high productivity and low cost achieved by high tool life during the operation. Laser cutting is considered the right solution because it offers cutting speeds of up to 170000 mm/min through a non-contact process regardless of the workpiece material hardness. The aim of this study is to analyze the effect of cutting speed on the surface texture aspects namely surface roughness, kerf shape, and dross height on the stainless steel 304 plate after laser cutting. The nitrogen laser was utilized with the cutting speed of 400, 1700, and 2000 mm /min and the average roughness (Ra) was then measured using a surface roughness tester. On the other hand, the top, middle, and bottom area of the kerf surface as well as the dross height were analyzed by scanning electron microscopy (SEM). The highest Ra value was resulted at cutting speed of 2000 mm/min with 2.965 ± 0.05 μm while the lowest was at 1400 mm/min with 2.522 ± 0.16 μm. In parallel, the Ra was found to be higher when subjected gradually from the top to bottom zone. The kerf surface also proved that the top zone is dominated by the cutting zone, while the middle and bottom zone are characterized by the transition and deformation zone respectively. The width between kerf lines increased when the higher cutting speed was performed. Additionally, the larger dross height was found at the cutting speed of 1400 mm/min with 32.75 ± 5.21 μm and then degraded gradually at the higher cutting speed. The heat input and laser capability in exposing the material thickness are responsible for determining the corresponding surface texture aspects.

The focus of manufacturing for tungsten carbide applications often demands a smooth surface quality as the result of the Electric Discharge Machine (EDM) die-sinking process, especially in the manufacture of die and mold with tungsten carbide material processed using a die-sinking EDM machine. The purpose of this study is to analyze the effect of electric current and pulse-on time on the Material Removal Rate (MRR) and surface roughness of tungsten carbide. Through the experimental method, the parameters varied, namely electric current 17 A, 20 A, 23 A, and pulse-on time 30 µs, 55 µs, and 80 µs. MRR was calculated through weight loss. Surface roughness was obtained from a surface roughness tester and a Scanning Electron Microscope for surface morphology. The results showed that the highest material removal rate was 1.509 mm3/min at 23 A and 30 µs, and the lowest material removal rate was 0.262 mm3/min at 17 A and 80 µs. The highest surface roughness value was 4.278 µm at 23 A and 80 µs. The lowest surface roughness value was 2.166 µm at 17 A and 30 µs. The tungsten carbide surface topography results are crater, globule, crack, and porous. The greater the current used, the higher the MRR value and surface roughness. Meanwhile, the greater the pulse-on time used, the MRR value decreases, and the surface roughness increases.

Extracted stevia leaves can be natural sweetener in pudding. This research aimed to obtain formulation of functional pudding with stevia leaf extract as a substitute for granulated sugar. This research used a simple randomized block design consisting of three replications. The treatments added were the proportion of sugar and stevia leaf extract, which consisted of six treatments, namely 170 g and 0 g, 136 g and 0.17 g, 102 g and 0.34 g, 68 g and 0.51 g, 34 g and 0.68 g, 0 g and 0.85 g. Variables of the tests carried out are rate fiber food, syneresis test, texture test, color test, pH test, and organoleptic test. The best treatment was pudding sugar 0 g and extract stevia leaves 0.85 g with average rate fiber 0.21 %, syneresis test 2.7167 mg min-1, gel strength 50.1 N, intensity color: brightness (L) 31.26, redness (a) 0.33, yellowish (b) 1.13, organoleptic: color 3.50 (fair), aroma 2.5 (no smell), taste 3.47 (enough delicious), texture 3.47 (enough soft), pH 7.41. Differences in the proportion of stevia leaf extract did not have a significant effect on the redness level and organoleptic variables of the pudding aroma but has a real effect on other variables, i.e rate fiber, syneresis, gel strength, brightness level, yellowish level, pH, color, taste, and texture.

The research aimed to determine the interaction of corn flour formulation, yellow sweet potato, arrowroot starch, and concentration of Gracilaria sp. seaweed slurry on the physicochemical properties of rice analogue. This research was conducted using a factorial randomized group design. This research consists of two factors. The first factor is the composite flour formulation (corn flour: yellow sweet potato flour: arrowroot starch) with different ratios; the second is Gracilaria sp. seaweed slurry concentration, which consists of four levels, namely 0 %, 1 %, 2 %, 3 % (w w-1). This research shows an interaction between the composite flour formulation and the concentration of Gracilaria sp. seaweed porridge on analogue rice’s water, fat, fibre, and antioxidant content. Analogue rice is known to have a water content ranging from 6.10 % to 8.25 %, ash content ranging from 1.45 % to 4.09 %, fat content ranging from 2.40 % to 5.91 %, and protein content ranging from 1.31 % to 3.60 %; carbohydrate levels range from 80.96 % to 87.99 %. Besides that, the analogue rice fibre content ranged between 1.33 % to 4.48 %, and the antioxidant activity was 83.32 % to 86.46 %.

Manufacturing time and energy consumption are two important parameters to evaluate the manufacturing process. The main purpose of this study was to analyze the energy consumption and printing time of 3D printed part between hollow and without any hollow structure. The specimen models were designed according to ASTM D368-IV standards and printed using a 3D printer device. During the printing process, the wall thickness of specimen was varied into three different types, 0.4 mm; 0.8 mm and 0.12 mm. Furthermore, the cavity was filled by polymer resin as main material for strengthening the specimen. Time and energy consumption of manufacturing process was recorded. In addition, the strength of specimens was observed using universal tensile test machine. The results showed that the highest manufacturing speed was occurred on the specimen that had wall thickness of 0.4 mm. Besides that, its parameter had a lowest energy consumption than specimen that had wall thickness 0.12 mm. The wall thickness showed the significant parameter to reduce the energy consumption, printing speed and material usage..

Friction Stir Welding (FSW) is a solid-state welding method that has diffusion and different metal structures can blend well. Friction stir welding (FSW) has a weakness, one of which is the lack of flexibility the welding process is only carried out on one side of the plate being welded, so it is not applied on thick materials. Double side friction stir welding is a double working process in which the plate to be welded is subjected to friction from two tools on opposite sides. In the DS-FSW welding process, the dimensions and geometry of the tool and pin greatly affect the quality of the joint. This study to determine the mechanical properties and corrosion rate of Double side friction stir welding aluminum 6061 with variation rotation speed and axis of top and bottom tools. The results of this radiographic test can be seen that specimen 4 welded with variations in speed and tool position has defects in the form of incomplete fusion (IF). The results of microstructural observations showed that the heat caused by the welding process resulted in recrystallization in the form of fine grains in the stirring area and there was no phase change. The highest hardness value in the welding area is specimen B. The largest bending value at the 1G welding positions is specimen D, which is 41.86 MPa with a strain value of 13.23%, while the smallest value at the 4G welding position is specimen A, which is 38.18 MPa with a strain value of 5.03%. The fracture and crack surfaces showed that crack initiation, propagation and material stirring failure occurred in all test specimens, even though the impact test specimen was cut in a small area of Incomplete Fusion, but the test results showed that there was still a surface of the parent metal that had not been stirred. The corrosion test method uses three electrode cells with corrosion media as a substitute for seawater with a salinity of 3.5% NaCl, result of corrosion test is specimen B at the 1G welding position has the highest corrosion rate value of 0.63856 mm/year and specimen An at the 1G welding position has the lowest corrosion rate of 0.058567 mm/year.

The protective ability of an organic inhibitor varies and is affected by the pH of the solution. Related with this fact, this work investigated corrosion inhibition performance of Bee Wax Propolis (BWP) extract on 304 SS in various environment (0–14 pH). The BWP extract inhibitor had formed a passive layer on the surface, indicated by the increase of the passive region. The inhibition efficiency changed randomly at all pH. The optimum inhibition efficiency for the acid and alkaline condition happened at pH 2 (96.60%) and 12 (97.75%). BWP was found to control corrosion better at pH 2 and 12.

A failure happens within the camshaft of the minibus when the vehicle is in utilize. The camshaft was a fracture within the bearing between the primary cylinder exhaust valve and the second cylinder suction. This simulation aims to find the causes of camshaft failure utilizing the finite element method with a static structural approach, including simulations of deformation, strain, stress, fatigue life (stress-life and strain-life), and cracks. The method used in this paper is the finite element method with a static structural approach by ANSYS software. The camshaft material is a gray cast iron designed using Solidworks. Pre-processing includes meshing with a size of 3 mm. The value of loading force (1348.28 N) and torque (113400 Nmm) are fixed, and the boundary conditions are varied. Processing includes the process of computation and post-processing into a part that displays the results. The simulation results show that for all the deformation and strain values that are in the elasticity area of the material, the maximum and minimum stress which is below the strength of the material, the location of the maximum values of deformation, strain, and stress is not at the fault location. The simulation of fatigue life both in stress-life and strain-life results in infinite cycles, which is above 106 cycles, while the simulation of cracks results in a decrease in the cycle. Based on the simulation results with the above parameters to the camshaft, it was found that a failure was caused by a defect characterized by reduced fatigue life at the same loading conditions.

This paper presents the development of Smartphone app for monitoring the heart rate, which used as a tool for life-based learning. The app featured life-based experiments for undergraduates' students through do-it-by-your-self activities. This app was developed with Firebase to create a heart rate monitoring system interface as well as a framework for life-based experiments. Also, this app had video features as learning resources. We used an experimental method to evaluate the proposed system of learning. The subjects were 30 undergraduate students who were separated into two groups. Based on our survey, student learning outcomes increased by 35 percent compared to conventional experiments.

The strength of 3D printed part is an important factor that must be considered before carrying out a product design. Moreover, manufacturing speed was also as key of successfully product design. The main focus of this study was to analyze the strength of 3D printed part and reduce the time manufacturing processing for getting the optimal design. The specimen models were designed according to ASTM D368-IV standards and printed using a 3D printer device. During the printing process, the infill density was varied into two different types, 0% and 100%. Meanwhile the main material used as a base material was Polylactic Acid or PLA which has an initial diameter of 1.75 mm. Furthermore, time consumption of manufacturing process was recorded, whereas the strength of specimens was observed using universal tensile test machine. The specimen model, especially for infill density 0% were added the resin polymer before carry out the tensile test. The results showed that the highest [1]tensile strength was occurred on the specimen that had the infill density of 100% without any addition of resin polymer. Besides that, the time consumption (infill density 0%) was showed significantly reduce than specimen that had infill density of 100%

The analog rice produced by UMM is made as a functional food by prioritizing good nutrition to make consumers healthy who consume it. The research objective is to analyze the characteristics of UMM analog rice consumers and the factors that influence consumer preferences for UMM analog rice in Malang. The research used a qualitative and quantitative approach by surveying 50 panelists in Malang City. Data were analyzed descriptively and factor analysis using SPSS. Consumer preferences of UMM Analog Rice are influenced by eight factors, namely product characteristics and health benefits, consumer income and personal factors, product preferences and roles, health perception and value factors, historical and promotional factors, price and marketing influence factors, marketing location factors, and product advantage factor. Product characteristics and health benefits are the factors that most influence consumer preferences for UMM Analog Rice in Malang. Product characteristics are the values contained in a product that describe the product. Originality/Value – UMM analog rice was introduced for diabetes mellitus sufferers. This study brings awareness to the importance of consuming nutritious and safe products for health.

This study aimed to analyze gluten free biscuits’s from purple sweet potato flour, rice bran flour, and coffee cherry flour; using completely randomized design method. The treatments applied were the ratio of adding purple sweet potato flour, bran flour and coffee cherry flour B0 (100 %: 0 % : 0 %); B1 (80 % : 20 % : 0 %); B2 (60 % : 30 % : 10 %); B3 (40 % : 40 % : 20 %); B4 (20 % : 50 % : 30 %); B5 (0 % : 60 % : 40 %) with four repetitions. The results showed that there was a significant effect between the proportions of the composite use of purple sweet potato flour, bran flour and coffee cherry flour on moisture content, ash content, fiber content, fracture power, color intensity and organoleptic taste. The best formulation was treatment B2 which had 5.05 % moisture content, 2.82 % ash content, 8.80 % protein content, 25 fat content, 05 %, carbohydrate content 58.28 %, crude fiber content 7.63 %, antioxidant activity 83.68 %, color intensity (L = 41.15; a = +5.05; b = +5.97), power broken 6.118 N, texture 4.52 (Slightly not crunchy), taste 5.40 (neutral), and aroma 5.60 (neutral).

A connecting rod is one of the most critical parts in engine assembly which transfers energy from the piston to the crankshaft. The connecting rod mainly undergoes tensile and compressive loading under engine cyclic process. The forces acting on the connecting rod are forces due to maximum combustion pressure and forces due to the inertia of the connecting rod. This research aimed to analyze the design of the connecting rod of single-cylinder four-stroke engines. This study used CAD software for modeling and structural design. Stresses generated across all the locations of the connecting rod were evaluated using FEA Software. Elastic linear analysis of model design was also performed. The simulation results in this study have led to the conclusion that failure occurred due to the incorrect selection of materials. Among all materials under study, AA 6061 is considered the most suitable material for use at high RPM. In fact, aluminum is preferable for use at high RPM.

This study aimed to determine the toughness of casts produced by the sand casting process at various temperatures against brass, and to investigate the structure contained in the cast madeusing abrass metal mould. This study was experimental research that observed the results of a treatment applied to a specimen group. This pre-experimental study usedthe one-shot case study model in which a group of samples was given treatment. The results showed that the specimen poured at 900°C exhibiteda microstructure consisting ofgood Cu-Zn content, while that at 700°Chad the least Cu content. It indicates that the higher the temperature used for metal casting (brass), the more brittle the cast. The toughness of the materialwas influenced by the alloy composition and the pouring temperature of each specimen; the higher the pouring temperature, the better the treatment of alloy. The photomicrographs indicate that the higher the pouring temperature usedin the metal casting (brass), the lesser the carbon element contained in the material.

A binder is any material used to strengthen the bonding of moulding sand grains. The primary function of the binder is to hold the moulding sand and other materialstogether to produce high-quality casts. In this study, there were four binder compositions being tested, i.e. 5% bentonite + 5% Portland cement, 4% bentonite + 6% Portland cement, 6% bentonite + 4% Portland cement, and 7% bentonite + 3% Portland cement. Each specimen was measured for its compressive strength, shear strength, tensile strength and permeability. The highest compressive strength was obtained fromthe specimen composed of 6% bentonite+ 4% Portland cement. The highest shear strength was obtained from the moulding sand with 7% bentonite+ 3%Portland cement. The highest tensile strength was obtained fromthe specimen contained 5% bentonite+ 5% Portland cement. The specimen composed of 5% bentonite + 5% Portland cement had the lowest permeability of 131 ml/min, while that of 6% bentonite + 4% Portland cement had the highest permeability of 176 ml/min.

This research aimed to investigate the fatigue crack behaviorof nodular cast iron heat-treated with two-step austempering. In this study, the material was initially reheated at 260 °C for 10 minutes, and then the temperature was increased to 280 °C, 310 °C, and 340 °C with the holding time of 60 minutes and 120 minutes. The results of these treatments showed that slower fatigue crack propagation occurred at the austempering temperature of 340 °C with 60-minutes holding time than those at lower temperatures (280 °C and 310 °C) and with longer time (120 minutes). The maximum fatigue crack propagation resistance occurred at the holding time of 60 minutes compared to that at the 120 minutes holding time.

This research is a preliminary study of which purpose is to find some information about corrosion behavior of brass casted product in nitric acid. The corrosion rate test was conducted by polarization and Electrochemical Impedance Spectroscopy (EIS). This study was run with the variation of nitric acid of 0,5; 1; 1,5; 2 M. Optical Microscope (OM) were used to explain and to confirm polarization and EIS result. A mechanism for the reactions taking place at the electrode/electrolyte interface was explained.

Leaf spring, as one of the main components of the suspension system, serves the function of absorbing road shocks and any wheel vibrations, preventing them from being transmitted directly to the vehicle body. Moreover, it can increase the tire traction as well as support the weight of the vehicle and various kinds of external forces. Various studies on the use of composite materials for leaf springs have shown that the strength of composite leaf spring is similar to steel leaf spring with the same load carrying capacity. However, the composite leaf spring has the added advantage of being more lightweight. In fact, composite materials have been preferable for many purposes not only because of its properties but also its lightweight structure and cost effectiveness. The analysis process was carried out using the finite element method by means of ANSYS software to display the output of the analysis being performed. After the output is known, the amount of voltage in conventional, mounted, and progressive spring can be determined. Based on the data analysis, we concluded that conventional straight leaf springs produced a maximum voltage of 653.13 MPa and maximum deflection of 4367.1 mm. The results of the analysis using the finite element method showed that conventional leaf springs (both straight and not) are considered as the most effective model of leaf spring in terms of the power generated.

The major factors determining the quality of sand casting products are the base sand and the composition of the sand mould and the binding material. In the foundry industry, the most commonly used binder for creating sand moulds is bentonite. However, the price of bentonite is likely to keep rising. This study aimed at discovering a new binder formula associated with the effect of binder composition i.e. bentonite, tapioca flour, and sago flour on the basis of its mechanical and physical properties. The new formula was expected to be a better binder in the production of sand moulds, resulting in high-quality casting products with minimal defects. Moreover, it is probable to be much more economical than bentonite. This research focused on testing the moulding sand composition with a number of different binders, i.e. bentonite, tapioca flour, and sago flour, each in a different proportion. The mixture of the moulding sand with each of the three binders will be tested in terms of its mechanical properties including compressive, shear, and tensile strength. Based on the test results, sago flour has the highest dry compressive strength of 28.6 N/cm2, whereas bentonite has the highest wet compressive strength, i.e. 11.83 N/cm2 and the highest wet shear strength i.e. 3.16 N/cm2. The binder with the highest dry shear strength is tapioca flour with 18.16 N/cm2. Regarding the tensile strength value, bentonite has the highest wet tensile strength of 0.85 N/cm2, while sago flour has the highest dry tensile strength of 1.73 N/cm2.

Pengaruh Penggunaan Bahan Dasar dan Bahan Tambah pada Minyak Pelumas terhadap Gejala yan Timbul pada KEndaraan Bermotor

Pengaruh Bilangan Oktana Bensin di Dalam Proses Pembakaran Kendaraan Bermotor

The extract of honeycomb waste was studied as a corrosion inhibitor on 304 stainless steel in H2SO4 solutions. The honeycomb waste was obtained from beekeeping at Lawang-Malang, East Java, Indonesia. Electrochemical and scanning electron microscopy methods were used to investigate the performance of the corrosion inhibition process. The inhibition efficiency of the inhibitor (2000 mg/L) reached 97.29% in 0.5 M H2SO4 and decreased with the acid concentration. Kinetic parameters were calculated to explain the effect of acid concentration on the inhibition process. The study on the adsorption behavior of the extracts followed the Frumkin isotherm model. The adsorption of the inhibitor on the 304 stainless steel surface was confirmed by the negative and lower values of Gibbs free energy. The obtained scanning electron microscopy (SEM) images were confirmed by comparing the surface of the specimens with and without inhibitor after corroding for one week. The results indicated that the extract acted as a good inhibitor for 304 stainless steel in acid corrosion.

This aim of this research is to determine the contribution of self-regulated learning and social skills towards the achievement of vocational competence of vocational students packages machining engineering expertise in the city of Makassar. Type and data analysis of this study are included in the quantitative approach. The samples used as many as 150 students in class XI. Data collection techniques for the variable self-regulated learning and social skills using questionnaires while variable vocational competency achievement using tests and documentation. Data analysis included descriptive and regression. The results showed: (1) self-regulated learning contributes to the achievement of vocational competence of 7,67%; (2) social skills contribute to the achievement of vocational competence of 4,28%; and (3) contribution of self-regulated learning and social skills of students simultaneously towards the achievement of vocational competence of 40,5%. Penelitian ini bertujuan untuk mengetahui seberapa besar kontribusi kemandirian belajar dan keterampilan sosial terhadap pencapaian kompetensi kejuruan siswa SMK paket keahlian teknik permesinan di kota Makassar. Jenis dan data analisis penelitian ini termasuk dalam penelitian kuantitatif. Jumlah sampel yang digunakan sebanyak 150 siswa pada kelas XI. Teknik pengumpulan data untuk variabel kemandirian belajar dan keterampilan sosial menggunakan angket, sedangkan variabel pencapaian kompetensi kejuruan menggunakan tes dan dokumentasi. Analisis data meliputi deskriptif dan regresi. Hasil penelitian menunjukkan: (1) kontribusi kemandiran belajar terhadap pencapaian kompetensi kejuruan sebesar 7,67%; (2) kontribusi keterampilan sosial terhadap pencapaian kompetensi kejuruan sebesar 4,28%; (3) kontribusi kemandirian belajar dan keterampilan sosial siswa secara simultan terhadap pencapaian kompetensi kejuruan sebesar 40,5%.

Penyusunan buku teks harus menyesuaikan kurikulum yang ber­laku yaitu ku­rikulum 2013. Realita menunjukkan tidak semua bu­ku memiliki kualitas isi dan ke­se­suaian isi seperti KI dan KD dalam kurikulum. Ba­nyak buku teks yang disusun ti­dak menyesuaikan pendekatan scientific yang berlaku di kurikulum 2013. Kondisi ter­sebut bertentangan denganfungsi buku teks dibuat yaitu untuk menunjang proses bel­ajar sesuai materi KI dan KD yang tercantum dalam kurikulum 2013. Hal tersebut be­lumdipenuhi secara ideal ada beberapa buku teks perlu dikaji ulang.Peningkatan kua­­­litas buku teks, salah satunyabuku Mekanika dan Elemen Mesin SMK Kelas X, per­lu adanya kajian terkait kesesuaian isi buku yang dapat menunjang pem­bel­ajaran de­ngan pendekatan scientific sesuai dengan kurikulum 2013 serta bagaimana se­­­­­­­ha­rus­nya buku disusun dengan menggunakan pendekatan scientific.

The goals of this research is to describe more fully about the implications sarjana mengajar program in terms of success for fulfillment of vocational high school teachers, learning management, and improving the quality of learning. This research is qualitative descriptive study with multi-site research. The techniques of data analysis is descriptive qualitative analysis. Based on the data analysis results, there were three conclusions. First, sarjana mengajar program was on target for fulfillment of vocational high school teachers in the school target. Second, the role of sarjana mengajar participants for developing learning management in school target was already quite good, but still need improvement in some aspects of that learning objectives can actually be achieved. Third, sarjana mengajar program had a role to improving the quality of learning in schools target, but still needed more in-depth scrutiny to continue improving the quality of learning. Penelitian ini bertujuan untuk mengkaji secara lebih dalam terkait implikasi program sarjana mengajar ditinjau dari segi keberhasilan dalam pemenuhan guru SMK, manajemen pembelajaran, dan peningkatan mutu pembelajaran. Jenis penelitian yang digunakan adalah penelitian deskriptif kualitatif. Rancangan penelitiannya yaitu studi kasus multisitus. Teknik analisis data yang digunakan adalah analisis deskriptif kualitatif. Berdasarkan analisis data, diperoleh 3 kesimpulan. Pertama, program sarjana mengajar tepat sasaran dalam pemenuhan guru SMK di sekolah tujuan program. Kedua, peran peserta sarjana mengajar dalam mengembangkan manajemen pembelajaran di sekolah tujuan program sudah cukup baik, namun masih perlu adanya perbaikan pada beberapa aspek agar tujuan pembelajaran benar-benar dapat dicapai. Ketiga, program sarjana mengajar turut berperan dalam peningkatan mutu pembelajaran pada sekolah tujuan program, namun masih diperlukan pengawasan yang lebih mendalam untuk terus meningkatkan mutu pembelajaran.

Chassis on the vehicle serves as the main weight support vehicle. Designing a precise chassis will give optimal results between the safety level and the size of the construction, so that finite element simulation analysis is required to know how strong the chassis sustains the load on it. The purpose of this research is to get the result of chassis simulation on UM electric car when getting the loading by using ANSYS 18.1 software. As for the step this study started from chassis modeling using Autodesk Inventor Professional 2018 software and finite element simulation using static structural feature in software ANSYS 18.1. From the simulation result obtained Equivalent Stress 59,983MPa, Equivalent Elastic Strain 33,25x10-5 mm / mm Total Deformation 2,43mm and safety factor 3,55.

In hot conditions and with various parameters, it has been found several cracks and wear in the hot rolling process due to several factors including von mises stress and plastic strain which is affected by the size of the roller diameter and thickness of the specimen. Modeling and optimization using Response Surface Methodology (RSM) are chosen in this study to determine the optimum parameter design. The effect of roller diameter and thickness of specimens on equivalent stress von mises and plastic strains on the hot rolling process were studied using RSM. Central Composite Design (CCD) with two factors and three levels which are part of the RSM used to present mathematical models. Based on the results of RSM the optimum value obtained is on the roller diameter of 577.1389 mm and the thickness of the specimen 8.5786 mm.

This study aimed to enhance the properties of aluminium-silicon (Al-Si) alloys by adding zinc oxide as a reinforcing material. This study was a type of pre-experimental design called the one-shot case study, in which sample groups subjects were given treatments and then observed. The steps included melting the aluminium-silicon in a furnace at 900° C, adding a certain amount of zinc oxide (0.05%, 0.1%, or 0.2%), stirring the mixture for 1 minute, and pouring it into a permanent mould. Results showed that, among the three specimens, the specimen reinforced with 0.2% zinc oxide had the highest tensile strength of 23.9 kg/mm2, the greatest hardness of 134.4 HV, and a flat surface with evenly distributed grains and more brittle fracture.

The combustion of fuel takes place inside the cylinder with the oxygen of the air, producing a very high-pressure combustion gas. The combustion gas does work on the piston and then passes through the connecting rod to the crankshaft. The reciprocating translational motion of the piston may damage the connecting rod. A simulation using ANSYS was performed on each of the three connecting rod materials. Results showed that the maximum deformation occurred in the connecting rod made of structural steel, aluminium alloy, and titanium alloy was 0.239 mm, 0.672 mm, and 0.496 mm, respectively.

Bones play an integral role in human survival. Damage to the knee joint has prompted orthopaedic specialists to develop implants as one of the solutions. In this study, Ti6Al4V as the implant material was optimised to determine and achieve the optimum implant condition based on the loading applied and the total deformation occurred. The optimisation results showed that the activity of walking downstairs resulted in the highest average of total deformation (19345 mm), followed by walking (15984 mm) and jumping (2.94 mm).

The body shape that is engineered in such a way will produce fluid flow characteristics that very and greatly affect the function of the shape of the body. However, until now researchers have not been able to find the right solution to diagnose and synthesize flow structures, so that it is done directly through experimental testing [3]. One of them by using the help of a software CFD (Computational Fluid Dynamics) is Ansys 18.1. Fluid Flow Analysis on the surface of the body electric car UM produces several characteristics such as fluid flow which has a significant obstacle, especially on the surface that has a wide surface that causes a flow that causes the flow is red which indicates the velocity of air flowing in that large area obtained maximum velocity air results of 21.1885m / s marked with the color red and velocity minimum of 0.03947m / s marked in blue, other than that when the air flows produce a pressure that produces the maximum pressure received by the body of 79.12Pa and the minimum pressure of -316.1Pa and the value of drag coefficient from the car body electric car UM obtained results of 0.46.

A connecting rod is the core component of an engine which has a function to transmit power released from combustion from the piston to the crankshaft. Deformation is the most commonly occurring damage to connecting rods. The connecting rods made of structural steel, aluminium alloy and titanium alloy were designed using Autodesk Inventor and analysed using ANSYS. The simulations showed the following results. The connecting rod made of structural steel had the highest maximum stress of 82.791 MPa. The connecting rod made of aluminium alloy had the highest maximum deformation of 0.84071 mm. The three connecting rod materials had the same maximum safety factor, i.e. 15.

Tannin isolated from Psidium guajava leaves are developed to enhance the corrosion protection of austenitic stainless steel. It is used as a green inhibitor, extracted from Psidium guajava which grow in East java, Indonesia. In the present work, the corrosion inhibition properties of the tannin inhibitors were investigated in 3M HCl by polarization potentiodynamic measurements. The result reveals that tannin 1g/L could enhance the inhibition efficiency up to 91.81%.

Bone is the connective tissue in the human body which consists of cells, fibers, and extracellular matrix. The bone matrix is the hardest part located in the outer layer of the bone, which is caused by the deposition of minerals in the matrix, so that the bone undergoes classification. The bone functions as a hard, rigid body frame, and provides a place or space for attachment of muscles and organs found in the human body. The simulation results using FEM showed that knee implants made with Ti6Al4V material had a total deformation of 0.15 mm, maximum principal stress of 17.012 MPa, and a maximum shear stress of 15.841 MPa. The analysis was performed using a variation of time 0 to 1.01 seconds.

Ammonia synthesis requires high pressure and high temperature process. Unfortunately, the capital intensive cost resulting low yield of ammonia by using recent catalyst which is iron oxide. Therefore, manganese zinc ferrite as a soft ferrite material will be introduced as a new nanocatalyst to enhance the ammonia yield. As a new nanocatalyst for ammonia production, study of comparasion two different concentration of MnZn Ferrite is very important. This paper will compare the yield of ammonia by using two different nanocatalyst which are Mn0.4Zn0.6Fe2O4 and Mn0.6Zn0.4Fe2O4. Both were synthesized by sol-gel method and has been characterize by using FESEM (morphology), XRD (phase identification), EDX (elemental analysis) and TPR (oxide reduction). The ammonia was produce with and without magnetic field applied. The result shows that the ammonia yield is higher for Mn0.4Zn0.6Fe2O4 nanocatalyst than Mn0.6Zn0.4Fe2O4 by using magnetic field applied. 67.2% of yield has been achieved by using new nanocatalyst Mn0.6Zn0.4Fe2O4 and magnetic field applied at ambient environment.

Nodular cast iron comes to be the most used material in manufacturing industry. Recently, a number of engineering to enhance the mechanical properties of nodular cast iron have been being given including through the heat treatment called single-step austempered. In general, the process of single-step heat treatment is conducted through austenization at the temperature of 900°C with the holding time of 60 minutes and quenched at various austempered temperatures of 280, 310, and 340°C in the holding time of 60 and 120 minutes. The observation on fatigue crack behaviour was performed in comparison of stress R=0 and at 11-Hz frequency. From the result of the research, a graphic about relationship of crack length (a) and the number of cycles (N), and the graphic of the fatigue crack growth rate (da/dN) with the stress intensity factor of (Δk). In addition, it is found that the single-step austempered heat treatment at the austempered temperature at 340°C with the holding time of 120 minutes showed a slower fatigue crack growth rate in comparison to the temperature and time below. The slowness of the fatigue crack growth rate was caused by the higher percentage of the pearlite matrix phase in comparison to the ferrite matrix, nodular distance, and the relatively even nodule distribution.

Carbonitriding is a surface hardening process of steel by heating on critical temperature, quench and followed by tempering process. In this research, pack media in carbonitriding was used as a new method. Usually, this process has been obtained using gas and liquid carbonitriding methods. The specimen used in this research is low carbon steel (St. 41) consist of 0.1517% carbon, 0.1994% of silicon, 0.5631% of manganese, 0.0224% of phosphorus, and 0.047% of sulfur. Temperature for pack carbonitriding was at 700 °C, 750 °C and 800 °C and holding time variation 60 minutes and 120 minutes respectively. The result showed that carbonitriding temperature difference affect the mechanical properties of steel St. 41. Steel hardness was increased at lower holding time (60 minutes) compared to 120 minutes. The result showed that at 700 °C and 750 °C with 60 minutes variation, the steel hardness increase from 85.7 HRB to 95.7 HRB and at 800 °C the hardness decrease to 93.1 HRB. Meanwhile, at holding time of 120 minutes, steel hardness decrease from 94.1 HRB to 92.7 HRB. This result caused by austenite phase produced at longer period of holding time.

The teachers have strate­gic roles in education. Even good education resour­ces are often meaningless unless equipped with highly qualified teachers. Therefore, a study needs to be conducted to exa­mine whether the certified teachers really have the competencies as stated in Minister of National Education Regulation No 16 2007. This method of research is a descriptive study to describe the teaching performance of the certified teachers at vocational schools especially on Industrial Engineering in Malang Muni­cipality. The study finds that the majority (78.77%) of the certified teachers seen from pedagogic competency is categorized as good, personal competency (78.38%) can be categorized as good, the majority (77.42%) of the social competen­cy can be categorized as good, and the majority (76.95%) of the professional compe­ten­cy can be categorized also as good. Guru mempunyai peran strategis dalam pendidikan. Meskipun sumber daya pendidikan yang baik seringkali tidak berarti tanpa dilengkapi dengan guru yang berkualitas tinggi. Oleh karena itu, sebuah studi perlu dilakukan untuk menguji apakah guru yang disertifikasi telah mempunyai kompetensi seperti dinyatakan dalam Permendiknas No 16 Tahun 2007. Metode penelitian ini adalah studi deskriptif untuk menjelaskan kinerja guru yang disertifikasi pada sekolah kejuruan khususnya pada Rekayasa Industri di kawasan Malang. Hasil studi menunjukkan bahwa sebagian besar (78,77%) dari guru yang disertifikasi me­m­­iliki kompetensi pedagogik baik, 78,38% mempunyai kompetensi kepribadian baik, 77,42% mempunyai kompetensi sosial baik, dan 76,95% mempunyai kom­pe­tensi profesional baik.

Proses chemical milling merupakan proses non traditional yang mampu mengurangi dimensi benda, apabila pada proses traditional machine sulit dilakukan. Akan tetapi kelemahan dari proses chemical milling adalah terjadi pengikisan permukaan, sehingga menyebabkan permukaan menjadi kasar. Kekasaran permukaan akibat proses chemical milling akan menimbulkan konsentrasi tegangan, dan hal itu berakibat timbul initial crack, sehingga akan mempercepat laju perambatan retak. Keberhasilan proses chemical milling juga sangat ditentukan oleh larutan etsa serta jenis maskant yang digunakan. Larutan etsa yang biasa digunakan untuk proses chemical milling adalah: NaOH, Na2S, HCl, dan HNO3. Sedangkan bahan maskant yang digunakan meliputi neoprene, polyvinilcloride, dan polyethiline.