A STRUCTURED RELIABILITY AND MAINTAINABILITY ASSESSMENT MODEL: AN APPLICATION TO HIGH VOLTAGE MOTORS

Motors are one of the vital equipment and generally the higher in numbers in oil and gas processing facilities. The primary function is to drive the process equipment such as compressors, fans, pumps etc. Unreliability of the motors is a threat to safety but also to production loss and high operating expenditure. Motors experience higher failure rates and maintenance costs with age due to lower focus during useful life periods. In order to properly address the long-term reliability and maintainability of the motors and associated subsystems, this paper aims to propose a structured methodology and set of tools to ensure effective assessment. The proposed model mainly consists of data collection, analysis, assessment, financial analysis and later developed actions to properly address the concerns. Equipment failure and repair data is a challenge to any reliability assessment; hence, proposed methodology was introduced to collect, verify and validate the data. Later, multiple tools such as Pareto Analysis, Failure Mode and Effect Analysis and Root Cause Analysis were used to perform a detailed assessment. Weibull analysis was also explored to understand the failure modes, which ultimately helped in improving the availability of the motors. The proposed methodology has been applied to high-voltage motors to observe the effectiveness of the tools and proposed model in addressing reliability and maintainability. The results show significant reliability improvements of 12% (from 58% to 70%) and prove that the structured method can be effectively used in complex process facilities with significant benefits

The Effect of Si and Extrusion Process on the Microstructure and Tensile Properties of Mg-Mg2Si Composite

AbstractThis investigation has been carried out to study the influence of extrusion process on microstructure and tensile properties of Mg-Mg2Si composite with different amounts of Si (3, 5 and 7wt.%). Microstructural examination was carried out using optical microscopy (OM). The cast specimens were extruded at 350°C at different extrusion ratios (6:1, 12:1 and 18:1). The results showed that the specimens with lower Si contents, have higher ultimate tensile strength (UTS) and tensile elongation values. Moreover, there was a considerable improvement in tensile properties for the specimens extruded with the ratio of 12:1 and 18:1 in comparison to the specimens of 6:1. This can be attributed to the significant reduction in size of primary Mg2Si particles from more than 200μm to 20μm, 10μm and 5μm after extrusion with the ratio of 6:1, 12:1 and 18:1, respectively. The highest UTS values were found to be 265MPa for extruded with 1:18 ratio of Mg-3Si composite

Meningkatkan Ketrampilan Berpikir Kritis Menggunakan Bimbingan Konseling Kelompok Teknik Problem Solving Berbantuan Mind Mapping

The purpose of this study was to test the effectiveness of group guidance on mind mapping and problem solving techniques to improve students' critical thinking skills in mathematics. This study used a random control group pretest-posttest design, involving 14 students of SMKN 3 Sukabumi. The data analysis technique used is one-way Anova. The results showed that the group guidance of mind mapping and problem solving techniques was effective in improving students' critical thinking skills in mathematics. Through this research, it is expected to be able to provide understanding to students that it is important to have critical thinking skills because students have developmental tasks that must be achieved in order to develop optimally with regard to mathematics subjects to be more responsible and consequently

Hubungan antara Kecemasan dan Kecanduan Internet dengan Insomnia pada Mahasiswa Yang Sedang Skripsi

The purpose of this study was to determine the relationship between anxiety and internet addiction with insomnia in students who are doing their thesis. This study uses a non-experimental quantitative design. Taking the subject using purposive sampling. Respondents in this study were 40 people. Data collection uses 3 instruments; insomnia scale, internet addiction scale, anxiety scale. Data analysis used multiple linear regression with the help of SPSS. The results of this study indicate that there is a significant relationship between anxiety and internet addiction with insomnia in students who are doing their thesis. The higher the level of anxiety and internet addiction, the higher the level of insomnia experienced by students.Tujuan dari penelitian ini adalah untuk mengetahui hubungan kecemasan dan kecanduan internet dengan insomnia pada mahasiswa yang sedang skripsi. Penelitian ini menggunakandesain kuantitatif non eksperimental. Pengambilan subjek menggunakan purposive sampling. Responden dalam penelitian ini sebanyak 40 orang. Pengumpulan data menggunakan 3 instrumen; skala insomnia, skala kecanduan internet, skala kecemasan. Analisis data menggunakan regresi linier berganda dengan bantuan SPSS. Hasil dari penelitian ini menunjukkan bahwa terdapat hubungansignifikanantara kecemasan dan kecanduan internet dengan insomnia pada mahasiswa yang sedang skripsi. Semakin tinggi tingkat kecemasan dan kecanduan internet maka semakin tinggi juga tingkat insomnia yang dialami siswa

Case of corrosion control in a closed cooling system

The cooling system of the food is one of the main essential systems to maintain food quality in the food processing plant. The using of corrosion inhibitor for the cooling systems is a familiar practice to control the corrosion which is happening due to a different kind of parameters like water quality and the type of materials for the cooling system, in this work, the case of adding corrosion and scale inhibitor to a cooling system containing carbon steel and stainless steel and copper was investigated. The inhibitor was mixed of two materials which are (Sodium Tripolyphosphate as a scale inhibitor and Sodium Polyphosphate as a corrosion inhibitor). The results demonstrate that there is an improvement in reducing the corrosion rate for iron after adding the inhibitor, and the copper ions in the solution reduced if the PH values below 9.5

A standard tag set expounding traditional morphological features for Arabic language part-of-speech tagging

The SALMA Morphological Features Tag Set (SALMA, Sawalha Atwell Leeds Morphological Analysis tag set for Arabic) captures long-established traditional morphological features of grammar and Arabic, in a compact yet transparent notation. First, we introduce Part-of-Speech tagging and tag set standards for English and other European languages, and then survey Arabic Part-of-Speech taggers and corpora, and long-established Arabic traditions in analysis of morphology. A range of existing Arabic Part-of-Speech tag sets are illustrated and compared; and we review generic design criteria for corpus tag sets. For a morphologically-rich language like Arabic, the Part-of-Speech tag set should be defined in terms of morphological features characterizing word structure. We describe the SALMA Tag Set in detail, explaining and illustrating each feature and possible values. In our analysis, a tag consists of 22 characters; each position represents a feature and the letter at that location represents a value or attribute of the morphological feature; the dash ‘-’ represents a feature not relevant to a given word. The first character shows the main Parts of Speech, from: noun, verb, particle, punctuation, and Other (residual); these last two are an extension to the traditional three classes to handle modern texts. ‘Noun’ in Arabic subsumes what are traditionally referred to in English as ‘noun’ and ‘adjective’. The characters 2, 3, and 4 are used to represent subcategories; traditional Arabic grammar recognizes 34 subclasses of noun (letter 2), 3 subclasses of verb (letter 3), 21 subclasses of particle (letter 4). Others (residuals) and punctuation marks are represented in letters 5 and 6 respectively. The next letters represent traditional morphological features: gender (7), number (8), person (9), inflectional morphology (10) case or mood (11), case and mood marks (12), definiteness (13), voice (14), emphasized and non-emphasized (15), transitivity (16), rational (17), declension and conjugation (18). Finally there are four characters representing morphological information which is useful in Arabic text analysis, although not all linguists would count these as traditional features: unaugmented and augmented (19), number of root letters (20), verb root (21), types of nouns according to their final letters (22). The SALMA Tag Set is not tied to a specific tagging algorithm or theory, and other tag sets could be mapped onto this standard, to simplify and promote comparisons between and reuse of Arabic taggers and tagged corpora

Carbon dioxide interaction with isolated imidazole or attached on gold clusters and surface: Competition between σ H-bond and π stacking interaction

Using first principle methodologies, we investigate the subtle competition between σ H-bond and π stacking interaction between CO 2 and imidazole either isolated, adsorbed on a gold cluster or adsorbed on a gold surface. These computations are performed using MP2 as well as dispersion corrected density functional theory (DFT) techniques. Our results show that the CO 2 interaction goes from π-type stacking into σ-type when CO 2 interacts with isolated imidazole and Au clusters or surface. The balance between both types of interactions is found when an imidazole is attached to a Au 20 gold cluster. Thus, the present study has great significance in understanding and controlling the structures of weakly-bound molecular systems and materials, where hydrogen bonding and van der Waals interactions are competing. The applications are in the fields of the control of CO 2 capture and scattering, catalysis and bio- and nanotechnologies. © 2014 the Partner Organisations