65 research outputs found
Gambaran Tingkat Pengetahuan Tentang Penggunaan Lensa Kontak pada Siswa dan Guru di Sekolah Menengah Atas Negeri 1 dan 9 Kota Pekanbaru
Contact lens is a result of technology in ophthalmology which is used as an alternative for eye glasses to correct the refractive error. The use of contact lens also has negative effect mainly for those who use it continuously without paying attention to its health impact. This research aimed to assess knowledge about the use of contact lens in students and teachers of Sekolah Menengah Atas Negeri (SMAN/State High School) 1 and SMAN 9 Pekanbaru. The research was done in both high schools room on December 2015. Population amount of this research was 353 which consisted of all class XI students and all teachers of SMAN 1 and SMAN 9 Pekanbaru. The sample taking method used was total sampling method. Primary data was taken and then managed by using computerized method. Data analysis used in this research was univariate and bivariate analysis. Result of the research showed that most of respondents (students) in SMAN 1 were female (21 persons, 52,5%), 25 persons (62,5%) of them use contact lens for fashion reason. There were 28 persons (70,0%) of respondents who had less knowledge about contact lens USAge. The cooperation between school and health worker especially ophthalmologist is needed to give information and improve the knowledge of students and teachers about the correct and safe use of contact lens
Laser Lap Joining of Dissimilar Materials: A Review of Factors Affecting Joint Strength
Laser joining of dissimilar materials has been the subject of intensive studies in the past decade or thereabout. This is mainly due to the
several benefits it offers when used to manufacture various electromechanical components for automotive, aerospace, electronics, and biomedical
applications. There are many possible variations of joining dissimilar materials; this article, however, considers the main engineering
materials in use today, namely, metal, polymer, ceramic, glass, and silicon. The strength of the joints determined by, inter alia, the material
combinations, joining technique, and material treatment is crucial for the above mentioned applications if safety and reliability requirements
are to be adhered to. Undoubtedly, the challenges posed by such complex selection of materials and process factors are unquantifiable and
as such have been given a critical review in this article. The relationship between some important laser processing parameters and joint
strength are also discussed. Furthermore, it has been observed that the joint strength can also be influenced by factors such as bubbles morphology,
material preparation/treatment, depth of molten pool and formation of chemical bonds, and intermetallic phases and their effects
are also reviewed and discussed. This article is concluded with an outlook providing the summary and key findings of the authors
Determination of optimum parameters using grey relational analysis for multi-performance characteristics in CO2 laser joining of dissimilar materials
This study concerns the employment of grey relational analysis to determine the optimized joint characteristics in CO2 laser lap joining of dissimilar materials classes. The joint characteristics, namely weld strength, weld width and kerf width are optimized as a function of laser power, its stand-off distance and the speed of welding. Due to a number of experimental constraints pertaining to joining polymer and glass-ceramic substrates, a full-factorial experiment is considered. Detailed images of the welded samples show the formation of crystallized glass leading to the failure of the joint. Thereafter, grey relational analysis (GRA) is employed to characterize the multiple quality characteristics of welded joint in terms of a relational grade. The set of the optimized processing parameters is determined based on the highest grade at 40 W laser power with a welding speed of 10 mm/s at a stand-off distance of 37 mm. Analysis of variance (ANOVA) is then carried out to ascertain the relative influence of process parameters on the joint characteristics. It was found that the weld speed has dominant effect on joint characteristics in comparison to stand-off distance at a fixed laser power
Cutting processes of natural fiber reinforced polymer composites
Recently, natural fiber-reinforced polymers (NFRPs) have become important materials in many engineering applications; thus, to employ these materials some final industrial processes are needed, such as cutting, trimming, and drilling. Because of the heterogeneous nature of NFRPs, which differs from homogeneous materials such as metals and polymers, several defects have emerged when processing the NFRPs through traditional cutting methods such as high surface roughness and material damage at cutting zone. In order to overcome these challenges, unconventional cutting methods were considered. Unconventional cutting methods did not take into account the effects of cutting forces, which are the main cause of cutting defects in traditional cutting processes. The most prominent unconventional cutting processes are abrasive waterjet (AWJM) and laser beam (LBM) cutting technologies, which are actually applied for cutting various NFRPs. In this study, previously significant studies on cutting NFRPs by AWJM and LBM are discussed. The surface roughness, kerf taper, and heat-affected zone (HAZ) represent the target output parameters that are influenced and controlled by the input parameters of each process. However, this topic requires further studies on widening the range of material thickness and input parameter values
Pengetahuan dan Sikap Ibu Hamil Risiko Tinggi dalam Mencegah Kematian Ibu Berdasarkan Tingkatan Komunikasi Interpersonal
Kematian dan kesakitan ibu masih merupakan masalah kesehatan yang serius di negara berkembang. Menurut laporan WHO (World Health Organization) tahun 2014 Angka Kematian Ibu (AKI) di dunia yaitu 289.000 jiwa. Penyebab kematian ibu terbanyak masih di dominasi perdarahan (30,3%), disusul hipertensi dalam kehamilan (27,1%), infeksi (7%). Penyabab lain-lain 45% cukup besar termasuk didalamnya penyebab penyakit non obstertik (Kemenkes RI, 2016). Pada tahun 2017 angka kematian ibu di Sulawesi Tenggara sebanyak 75 orang per tahun. Sedangkan di Kabupaten Kolaka Utara sebanyak 209 per 100.000 kelahiran hidup. Data dari puskesmas Lasusua, Kecamatan Lasusua, Kabupaten Kolaka Utara, Provinsi Sulawesi Tenggara memperlihatkan jumlah ibu hamil sebanyak 700 orang dan yang termasuk ibu hamil resiko tinggi sebanyak 140 orang. Metode penelitian ini merupakan penelitian kuantitatif. Desain penelitian yang digunakan yaitu cross sectional yang bertujuan untuk mengetahui hubungan tingkatan komunikasi interpersonal dengan perilaku ibu hamil risiko tinggi dalam mencegah kematian ibu di Puskesmas Lasusua Tahun 2020. Dalam penelitian ini populasi berjumlah 140 orang dengan menggunakan besar sampel penelitian ini menggunakan rumus Slovin. Pengambilan sampel dalam penelitian ini menggunakan probability sampling dengan teknik simple random sampling. Cara pengumpulan data dalam penelitian ini kuesioner dimana peneliti bertemu dengan responden dan respondenlah yang mengisi daftar pertanyaan tersebut. Dan cara menganalisis data penelitian dengan menggunakan SPSS. Hasil penelitian menunjukkan bahwa ada hubungan antara komunikasi interpersional dengan pengetahuan ibu hamil dengan nilai p (value) = 0,001. Tidak ada hubungan antara komunikasi interpersional dengan sikap ibu hamil dengan nilai p (value) = 0,976. Di harapkan pada peneliti selanjutnya sebaiknya meneliti tingkatan komunikasi kesehatan yang efektif yang mempengaruhi penyakit yang berhubungan dengan ibu hamil. Dan di harapkan petugas kesehatan dapat meningkatkan komunikasi interpersonal lebih efektif dengan ibu hamil risiko tinggi.
 
Little Princes: Petualangan Backpacker Amerika Menyelamatkan Anak-Anak Korban Perdagangan Manusia
460 hlm,; 20,5 c
An innovative approach to monitor the chip formation effect on tool state using acoustic emission in turning
Chip formation in metal cutting is inevitable and has a remarkable effect on tool state and therefore on the tool life. The work presented here introduce a new technique to independently monitor the chip formation effect on the tool state. This his been done by separating the chip formation events from the rest of the frequencies of occurrences. A customized tool holder and sensor setup are designed and integrated with the conventional tool holder to capture the signals from chip formation independently during turning. The signals taken by acoustic emission (AE) sensor represent the effect of chip formation on the tool state. The frequencies remaining below the transient offset signal are mostly coming from the tool wear and plastic deformation of the workmaterial. It has been observed that the acoustic emission is more susceptible to entire occurrences in turning. The time domain signal and corresponding frequency response can predict the tool state effectively. From raw AE signals and their RMS values, the tool wear and plastic deformation are observed to increase with the increase of cutting speed, feed rate and depth of cut. However, the tool wear has been found to decrease with chip breakage even at higher cutting speed and feed rate, and this has been verified by measuring the tool wear. The chip formation frequency has been found to vary between 68.3 kHz and 634.83 kHz while the maximum intensity was observed at 97.7 kHz
Laser cutting of square blanks in stainless steel-304 sheets: HAZ and thermal stress analysis
Laser cutting is a non-traditional cutting process and cutting of square blank in stainless steel-304 sheets cause heat affected zone (HAZ) and thermal stress. Formation of HAZ is undesirable and excessive stress cause surface defects. Thus, it is necessary to analyze them intensively. The process of laser cutting is a complex thermo-mechanical process. Hence, in this study a thermo-mechanical finite element model has been introduced by ANSYS to predict the temporal variation together with thermal stress and width of heat affected zone (HAZ). CO2 laser is used to cut 10 × 10 mm square blank in a 3 mm thick stainless steel-304 sheet. Optical microscope and SEM are used to analyse the parametric effect on surface quality at the cutting edge. The results showed that maximum temperature at the cutting edge is about to melting temperature and independent to laser power and cutting speed. Importantly, cutting speed has significant effect on rate of temperature variation. Moreover, the width of HAZ increases with the increase of laser power and decrease of cutting speed. However results of ANOVA suggested that laser power is the most significant parameter having 64.21% of contribution to width of HAZ. Furthermore, maximum stress is observed at the corner; which is supported by SEM analysis
A Two Pressure-Velocity Approach for Immersed Boundary Methods in Three Dimensional Incompressible Flows
This paper describes innovative method for computing fluid solid interaction using Immersed boundary methods with two stage pressure-velocity corrections. The algorithm calculates the interactions between incompressible viscous flows and a solid shape in three-dimensional domain. The fractional step method is used to solve the Navier-Stokes equations in finite difference schemes. Most of IBMs are concern about exchange of the momentum between the Eulerian variables (fluid) and the Lagrangian nodes (solid). To address that concern, a new algorithm to correct the pressure and the velocity using Simplified Marker and Cell method is added. This scheme is applied on staggered grid to simulate the flow past a circular cylinder and study the effect of the new stage on calculations cost. To evaluate the accuracy of the computations the results are compared with the previous software results. The paper confirms the capacity of new algorithm for accurate and robust simulation of Fluid Solid Interaction with respect to pressure field
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