22 research outputs found

    Analisis Pengaruh Suhu Preheating 125˚C, 150˚C Dan 200˚C Hasil Pengecoran Logam Terhadap Terjadinya Hot Tearing Menggunakan Material Alumunium 6061

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    The aluminum casting industry has experienced a lot of innovation and creativity to maintain its existence. Metal casting is a process by which hot molten metal is poured into a mold containing hollow pieces or cavities of the desired finished shape. The process of casting with a permanent mold is preheating the casting mold before the casting process is carried out. This is done so that the temperature of the casting mold increases, so that the difference between the temperature of the mold and the temperature of the aluminum to be poured is not too great. This study aims to overcome or prevent hot tearing by increasing the preheating temperature in the mold. The test results show that the preheating temperature of 200ÂșC does not experience shrinkage in the metal casting results. Whereas at preheating temperatures of 125ÂșC and 150ÂșC there are hot tearing defects and there is shrinkage. whereas at the preheating temperature variation of 200ÂșC there are only shrinkage defects. The results of the vickers hardness test showed that the higher the preheating temperature, the hardness value of the casting product will increase. The highest vickers hardness value was obtained at the 200°C preheating temperature variation of 69.55 HV, while at the 150°C preheating temperature variation, the vickers hardness value was 68.51 HV. and at a variation of the preheating temperature of 125ÂșC, the vickers hardness value is 67.04 HV. The results obtained from metallographic testing are aluminum 6061. Judging from the microstructure at the 200℃ preheating variation, the dentite grains look smaller than the 125℃ preheating variation and the 150℃ preheating variation. It can be concluded that the higher the preheating temperature, the better the denrite density.Industri pengecoran aluminium telah mengalami banyak inovasi dan kreativitas untuk mempertahankan keberadaannya. Pengecoran logam adalah proses dimana logam cair yang panas dituangkan ke dalam cetakan yang berisi potongan berlubang atau rongga dengan bentuk jadi yang diinginkan. Proses dari pengecoran dengan cetakan permanen adalah preheating cetakan coran sebelum dilakukan proses penuangan. Hal ini dilakukan agar temperatur cetakan coran mengalami peningkatan, sehingga perbedaan antara temperatur cetakan dengan temperatur aluminium yang akan dituang tidak terlalu jauh Penelitian ini bertujuan untuk mengatasi atau mencegah terjadinya hot tearing dengan cara menaikan suhu preheating pada cetakan. Hasil pengujian menunjukkan bahwa suhu preheating 200ÂșC tidak mengalami penyusutan pada hasil pengecoran logam. Sedangkan di suhu preheating 125ÂșC dan 150ÂșC terdapat cacat hot tearing defect dan terdapat penyusutan. sedangkan pada variasi suhu preheating 200ÂșC hanya terdapat cacat penyusutan. Hasil pengujian kekerasan vickers menunjukkan bahwa semakin tinggi suhu preheating nilai kekerasan hasil pengecoran akan semakin meningkat, didapat nilai kekerasan vickers tertinggi pada variasi suhu preheating 200ÂșC sebesar 69,55 HV, sedangkan pada variasi suhu preheating 150ÂșC didapatkan nilai kekerasan vickers sebesar 68,51 HV, dan pada variasi suhu preheating 125ÂșC didapatkan nilai kekerasan vickers yaitu sebesar 67,04 HV. Hasil yang didapat dari pengujian metalografi adalah pada aluminium 6061. dilihat dari struktur mikro pada variasi preheating 200℃ butiran denrite terlihat lebih kecil dibandingkan dengan variasi preheating 125℃ dan variasi preheating 150℃, Dapat di simpulkan semakin tinggi suhu preheating maka kerapatan denrite akan semakin bai

    Inspeksi Sambungan Rangka Mobil Listrik Tipe Tubular Space Frame Menggunakan Las GMAW dengan Cairan Liquid Penetrant

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    Technological developments increasingly require humans to increase their competence and innovation. The process of making frames for electric cars is one of the innovations to produce a strong frame. The frame is the main and important part of a vehicle, because the components and passengers will support the frame. The connection between frame components uses GMAW welding, which is the process of joining metal materials by heating them until they reach their melting point. To obtain a frame that meets the criteria, it is necessary to carry out a testing process, this testing process is NDT testing (Non Destructive Test), namely testing the physical part of the material in a way that does not damage the test object. Meanwhile, the aim of this research is to inspect the electric car frame so as to find discontinuities in the GMAW welding results. The results of this research were that there were 22 samples that underwent the liquid penetrant test process, of the total samples according to ASME Section VIII Division 1 Mandatory Appendix 6 there were 14 specimens that were acceptable while 8 needed improvement in the connection process. After the repair or repair process has been carried out, the frame is declared fit for use

    Analisis Pengaruh Variasi Suhu Tempering Pada Sifat Mekanik Baja ASTM A36 Setelah Pengelasan SMAW Menggunakan Elektroda E 7016

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    ASTM A36 is a type of structural metal that can be applied for various purposes such as making gears, bridge structures and ship buildings. After welding, ASTM A36 steel will produce residual stress. Residual stress in the welded metal is caused not balanced temperature distribution. The method for eliminating residual stress is tempering. Tempering is used to reduce residual stresses, increase the ductility and toughness of metals. This research aims to analyze the effect of variations in tempering temperature on the mechanical properties of ASTM A36 steel after SMAW welding using E7016 electrodes. The tensile strength test on the specimen showed the highest increase due to the tempering effect of 537,880 MPa at a temperature of 200°C. This is proven by the reduction in material hardness of 165.07 VHN at a tempering temperature of 200°C when compared to the hardness of the raw material. The growth of ferrite grains in the material structure shows that the ASTM A36 material is increasingly ductile after tempering. The results of research on the effect of variations in tempering temperature on the mechanical properties of ASTM A36 can be used as an alternative way to increase ductility after the welding proces

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    PENGUJIAN BUCKET ELEVATOR GEN.01 TM

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    Post-harvest agricultural products are all activities carried out from the process of handling agricultural products to the process that produces semi-finished products. Improper post-harvest handling will result in yield loss, both weight and product quality. Readiness of mature harvest and post-harvest technology will improve the quality of rice and the understanding of farmers and technology users in efforts to reduce crop losses. Bucket elevator is a tool for moving material that can be used to lift grain during the grain milling process, which can help work to move grain from the surface into the milling machine. In the Bucket Elevator test results, the effective rotational speed is 352.5 Rpm using a 1 hp 3 phase motor. The design of model 1 is the optimal bucket for lifting grain, resulting in a net weight of 243 gr/bucket contents with a maximum capacity of 280 gr/bucket. When attached to the Bucket carrier belt with 3 test results with different 1 hp motors get test results 1 = 22.5 kg/m , test 2 = 21.3 kg/m , and test 3 = 22.7 kg/m , with average result– average 22.1 kg/m. The noise test on the Bucket Elevator gets the results of noise intensity at 3 different points with an average value of point 1 (front) = 77.7 dBA, point 2 (side) = 72.0 dBA, and point 3 (top) = 77, 1dBA
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