A computational analysis of heat transfer and fluid flow in high-speed scanning of laser micro-welding

A transient three-dimensional model is numerically developed using computational fluid dynamics (CFD) method to understand some critical criteria such as temperature fields and melt pool formation by considering the heat source and the material interaction and the effect of laser welding parameters on laser micro-welding process. To gain more implicit insight of fluid dynamics, the issue of circulation of molten metal assisted by the surface tension, buoyancy and recoil pressure forces in the weld pool has been investigated Assuming that atmospheric and vaporised material pressures are balanced at the front of the laser beam. The governing equations from the Navier–Stokes for Newtonian fluid are prepared to estimate the melt flow that influences the rate of temperature distribution in a 3-D domain. The simulation results have been compared with two sets of experimental research to predict the weld bead geometry and solidification pattern which laser welds are made on thin stainless steel sheet (SUS304). The shape comparison describes those parameters relevant to any changes in the melt dynamics and temperatures are of great importance on the formation of weld pool and heat distribution during laser micro-welding. The fair agreement between simulated and experimental results, demonstrates the reliability of the computed model

Hubungan Intensitas Belajar dengan Hasil Belajar Matematika Siswa

The purpose of this study was to determine the relationship between learning intensity and mathematics learning outcomes of students at SD Inpres 1 Donggulu. The method used in this research was experimental research, this type of research was a quantitative research that was correlated to fifth grade elementary school students, the sample in this study was 16 students. The research data were obtained in two ways; distributing questionnaires containing a number of statements to which the respondent's students responded, and obtaining midterm test scores on Mathematics from students who had been designated as respondents. The data obtained were analyzed quantitatively using the help of Statistical Package for the Social Sciences (SPSS) software version 23 for windows. The results of data analysis shown that the significance value (0.002) ≥ 0.05. It indicated that there was a relationship between learning intensity and student learning outcomes with the degree of strong correlation was 0.717

Hubungan Intensitas Belajar dengan Hasil Belajar Matematika Siswa

The purpose of this study was to determine the relationship between learning intensity and mathematics learning outcomes of students at SD Inpres 1 Donggulu. The method used in this research was experimental research, this type of research was a quantitative research that was correlated to fifth grade elementary school students, the sample in this study was 16 students. The research data were obtained in two ways; distributing questionnaires containing a number of statements to which the respondent's students responded, and obtaining midterm test scores on Mathematics from students who had been designated as respondents. The data obtained were analyzed quantitatively using the help of Statistical Package for the Social Sciences (SPSS) software version 23 for windows. The results of data analysis shown that the significance value (0.002) ≥ 0.05. It indicated that there was a relationship between learning intensity and student learning outcomes with the degree of strong correlation was 0.717

Finite element analysis of elastomeric push-fit spigot and socket steel pipe joint

Spigot and socket push - fit joint is one of the methods, which can be used as pipe joining system. This technique was mostly used for small diameter pipe but has not been introduced for steel main pipe. With the co-operation from BOON & CHEAH STEEL PIPES SDN. BHD. company, a project has been developed to analyse the ability of the joint for 600mm steel pipes. Finite element method was used to analyse the ability of this joint. Two types of finite element software were used namely, LS-DYNA3D and LUSAS13. There were another two methods involved, theoretical and experimental methods, to support the finite element analysis of the joint. Elastomer, which was used in this study, used Mooney-Rivlin strain energy equation.!t has been identified that the permissible working pressure value for the joint occurred at the bottom surface of the elastomer. The value is higher than the water pressure in the pipe. From different cases studied by changing the thickness and width of the elastomer, the best pressure distribution developed was at t =3 mm and h = 0.5 l mm. For the pushing force analysis, it is identified that to fit the joint, the pushing force must exceed 10 kN. It is shown that the joint method can be used for large size steel pipe because the pressure value developed was higher than the internal water pressure. For the ease of joining, it has also been identified that the pushing force must be higher than the shear stress produced by the elastomer. Some recommendations have been proposed to get the most benefit of the analysis

Analysis of the Electronic Implementation of A Malaria Surveillance Information System (E-SISMAL) in the Lahat District

Background: The requirement for malaria elimination to be recognized is to prove API lower than 1 per 1000 in the population, together with no indigenous case. Lahat Regency is an area of low-endemicity for malaria, where the target for elimination is projected for 2024.  Since 2019, Lahat Regency has received socialization about E-SISMAL, which was developed as a web-based basis to speed up the reporting process. However, there are still delays in reporting malaria on E-SISMAL. Methods: Descriptive research with a qualitative approach was designed. The study subjects were the malaria person in charge, the head of seven selected community health centers (Puskesmas) and the Lahat District Health Office. Primary data came from observation, focus group discussion (FGD) and in-depth interviews with eighteen informants selected by the purposive sampling method. Results: The available inputs are inadequate, such as the human resource education was not up to standard, the internet network was not smooth, and there were no guidelines on E-SISMAL in the health centers. Malaria person in charge does not understand how to use E-SISMAL. In the process, there was the involvement of cross-sectoral and networked establishments. The output shows that the report indicators on E-SISMAL are not up to standard with less than 80%. Conclusions: The use of E-SISMAL in the Lahat district has not been maximized. It has an impact on delays in reporting. It is recommended that training and practice of E-SISMAL occur to improve officers' ability through socialization and that the Lahat Health Office establishes partnerships with telecommunications companies to ensure the smooth running of the network. Developing specific guidelines on E-SISMAL and a mobile phone-based malaria surveillance information system to speed up the malaria reporting process in the Lahat district is also advisable

Vegetation Characteristics and Carbon Stocks After Earthquake in Forest for Specific Purpose (Khdtk) Senaru

Kawasan Hutan Dengan Tujuan Khusus (KHDTK) or Forest for Specific Purposes in Senaru is a forest area designated for educational purposes. This study aims to assess ecological changes (i.e., vegetation cover, vegetation structure and diversity, and carbon storage) in KHDTK Senaru during three-time scales, namely in 2013 and in 2018; before and after the earthquake. Data were collected from 30 permanent quadratic plots, systematically distributed in these three different time scales. The vegetation cover resultsshow a decreasing vegetation cover in the dense class but increasing in middle and sparse density classes. Changes in vegetation structure and diversity are noticeable at all regeneration stages, while the carbon storage changes at each time scale. This study indicates that disturbance due to the earthquake has minimal effect on the species diversity than management practices. Therefore, we recommend that the manager or forest users to consider planting more species to increase diversity, improve ecosystemresiliency, prevent damage expansion, and decrease the ecological function of KHDTK Senaru

In-situ sterilization of microalgae photobioreactor via ozone-rich macrobubbles

Aseptic technique plays a critical role in determining high volumes of microalgae biomass during the cultivation stage as the presence of a contaminant is one of the limiting factors. This study focuses on developing an energy-efficient method in sterilizing the 2 L microalgae photobioreactor. Initially, the seawater bacterial contaminant was successfully screened, isolated and identified as Kurthia gibsonii. The photobioreactor sterilization using ozonolysis was optimized using one factor at a time (OFAT), with 3 parameters studied: ozone aeration rate (0.5 L/min, 1.0 L/min and 1.5 L/min), bacterial culture volume (1.0 L, 1.5 L, and 2.0 L) and ozonation time (maximum of 180 minutes with 30-minute intervals). The ozonation technique at optimum condition reduced the contaminants up to 7 log reductions. The initial cells concentration in 1 L culture containing 6.73×107 cells/ml was reduced to 7 cells/ml after being ozonated for 180 min. The morphology study of the bacteria before and after ozonation (at 1000X magnification) confirmed that ozonation shattered the cells into small pieces. This study reveals the possibility of replacing energy-intensive sterilization techniques such as the autoclave method with ozonolysis. Ozonation method is more energy efficient, with a total 1.26 kW energy used during the sterilization process as compared to autoclaved method with 3.565 kWh. The study proves that the ozonation method is energy efficient, cheaper and easily applied to a larger industrial scale as well

Genome-wide analysis of the CAD gene family reveals two bona fide CAD genes in oil palm

Cinnamyl alcohol dehydrogenase (CAD) is the key enzyme for lignin biosynthesis in plants. In this study, genome-wide analysis was performed to identify CAD genes in oil palm (Elaeis guineensis). Phylogenetic analysis was then conducted to select the bona fide EgCADs. The bona fide EgCAD genes and their respective 5′ flanking regions were cloned and analysed. Their expression profiles were evaluated in various organs using RT-PCR. Seven EgCAD genes (EgCAD1-7) were identified and divided into four phylogenetic groups. EgCAD1 and EgCAD2 display high sequence similarities with other bona fide CADs and possess all the signature motifs of the bona fide CAD. They also display similar 3D protein structures. Gene expression analysis showed that EgCAD1 was expressed most abundantly in the root tissues, while EgCAD2 was expressed constitutively in all the tissues studied. EgCAD1 possesses only one transcription start site, while EgCAD2 has five. Interestingly, a TC microsatellite was found in the 5′ flanking region of EgCAD2. The 5′ flanking regions of EgCAD1 and EgCAD2 contain lignin-associated regulatory elements i.e. AC-elements, and other defence-related motifs, including W-box, GT-1 motif and CGTCA-motif. Altogether, these results imply that EgCAD1 and EgCAD2 are bona fide CAD involved in lignin biosynthesis during the normal development of oil palm and in response to stresses. Our findings shed some light on the roles of the bona fide CAD genes in oil palm and pave the way for manipulating lignin content in oil palm through a genetic approach