ANALISA SIFAT MEKANIK DAN STRUKTUR MIKRO TERHADAP PENGELASAN BAJA AISI 1045 DENGAN METODE SMAW DAN GTAW PADA ARUS 100 AMPERE

Pengelasan adalah proses penyambungan logam atau non-logam yang dilakukan dengan memanaskan material yang akan disambung hingga temperatur las, yang dilakukan dengan atau tanpa menggunakan tekanan dan dengan atau tanpa menggunakan logam pengisi. Salah satu teknik pengelasan adalah dengan pengelasan SMAW (Shield Metal Arc Welding) dan GTAW (Gas Tungsen Arc Welding). Dengan las tersebut kita dapat menyambung logam seperti: Aluminium, Tembaga, Carbon Steel, dan Stainless Steel. Penelitian ini dilakukan untuk mengetahui sifat mekanik, struktur mikro, dan kekuatan sambungan las pada Baja AISI 1050. Pengelasan dilakukan dengan menggunakan tungsten TG-S50 untuk las GTAW dan elektroda E-6013 untuk las SMAW pada arus 100 Ampere dengan sambungan kampuh V 60o. Metode pengujian yang dilakukan adalah uji kekerasan dengan metode Brinell Hardness Tester, uji tarik dengan Tensile Tester, dan uji struktur mikro dengan Metallurgycal Microscope. Hasil rata-rata dari uji kekerasan Brinell didapat sifat mekanik baja AISI 1045 las SMAW pada daerah las dengan elektroda E-6013 pada arus 100 A adalah 160,04 BHN dan las GTAW dengan filer TG-S50 pada arus 100 A adalah 172,53 BHN. Nilai rata-rata tegangan las SMAW dengan elektroda E-6013 pada arus 100 A adalah 323,14 MPa dan las GTAW dengan filler TG-S50 pada arus 100 A adalah 411,57 MPa. Bentuk struktur mikro pada daerah lasan dengan pengelasan GTAW memiliki struktur mikro yang lebih kecil dibandingkan dengan pengelasan SMAW, hal ini membuktikan bahwa nilai kekerasan pada daerah lasan GTAW lebih besar dari pada nilai kekerasan pada daerah lasan SMAW

Evaluation of far-field tsunami hazard in French Polynesia based on historical data and numerical simulations

International audienceThe first tsunami hazard map of French Polynesia is presented here on the basis of historical data, and numerical simulations. French Polynesia, because of its central position in the most tsunami prone ocean, the Pacific, is strongly exposed to far-field tsunamis. As no previous study on the area had been conducted, we compiled catalogues of all the historical observations (14 events), and tide gauges records (69 marigrams). The catalogues emphasise the higher hazard associated to the Marquesas archipelago, but also the deficiency of robust data in most other parts of French Polynesia. The recourse to numerical simulations allowed us to complement the existing records, and to test tsunami scenarii over different bathymetry and topography configurations, representative of the diversity of islands in French Polynesia. The tsunami hazard map assigns a high exposure level to the Marquesas and the island of Rurutu. Other islands of the Austral, and the Gambier archipelago have a elevated level of exposure, as well as three islands of Society: Tahiti, Moorea, and Huahine. All other islands of French Polynesia are considered as moderately exposed

Arabidopsis glucosinolates trigger a contrasting transcriptomic response in a generalist and a specialist herbivore.

Phytophagous insects have to deal with toxic defense compounds from their host plants. Although it is known that insects have evolved genes and mechanisms to detoxify plant allochemicals, how specialist and generalist precisely respond to specific secondary metabolites at the molecular level is less understood. Here we studied the larval performance and transcriptome of the generalist moth Heliothis virescens and the specialist butterfly Pieris brassicae feeding on Arabidopsis thaliana genotypes with different glucosinolate (GS) levels. H. virescens larvae gained significantly more weight on the GS-deficient mutant quadGS compared to wild-type (Col-0) plants. On the contrary, P. brassicae was unaffected by the presence of GS and performed equally well on both genotypes. Strikingly, there was a considerable differential gene expression in H. virescens larvae feeding on Col-0 compared to quadGS. In contrast, compared to H. virescens, P. brassicae displayed a much-reduced transcriptional activation when fed on both plant genotypes. Transcripts coding for putative detoxification enzymes were significantly upregulated in H. virescens, along with digestive enzymes and transposable elements. These data provide an unprecedented view on transcriptional changes that are specifically activated by GS and illustrate differential molecular responses that are linked to adaptation to diet in lepidopteran herbivores

Quantifying the Impact of Social Media on Adolescent Delinquency

This study examines social media's quantitative effect on juvenile criminality. The researcher intends to quantify how social media usage affects juvenile delinquency. The research will examine mediating elements, including peer influence, self-esteem, and antisocial content. This study may educate parents, educators, politicians, and mental health experts on adolescent social media usage hazards. This study aims to establish evidence-based social media mitigation and youth development solutions. This research employed quantitative methodologies. The target population for this study will be two hundred (200) criminology students of Headstart College of Cotabato. Participants will be selected using a time-efficient random selection strategy. The findings of a power analysis will be used to calculate the sample size needed to achieve the desired level of statistical significance. The researcher will administer the survey questionnaire face-to-face after proper coordination with the College head. Respondents had enough time to complete the survey questions. The researcher and respondents will complete the questionnaire in their own time to gather and retrieve data: data quantification, categorization, and statistical description. Weighted mean and correlation were utilized to assess the association between social media use and teenage delinquency and behavior. The researcher carried out all methods using SPSS Application Guide as statistical software. The study revealed that excessive social media use is associated with negative outcomes such as mental health issues, decreased social interactions, and potential impacts on academic performance. Additionally, the level of parental monitoring and communication regarding social media usage was varied, and family conflict related to social media use was evident to some extent. There needs to be more research done to determine the mechanisms that link adolescent social media usage and behavior. Longitudinal studies may help explain what happens and why, as well as suggest any necessary countermeasures

Experiments towards quantum information with trapped Calcium ions

Ground state cooling and coherent manipulation of ions in an rf-(Paul) trap is the prerequisite for quantum information experiments with trapped ions. With resolved sideband cooling on the optical S1/2 - D5/2 quadrupole transition we have cooled one and two 40Ca+ ions to the ground state of vibration with up to 99.9% probability. With a novel cooling scheme utilizing electromagnetically induced transparency on the S1/2 - P1/2 manifold we have achieved simultaneous ground state cooling of two motional sidebands 1.7 MHz apart. Starting from the motional ground state we have demonstrated coherent quantum state manipulation on the S1/2 - D5/2 quadrupole transition at 729 nm. Up to 30 Rabi oscillations within 1.4 ms have been observed in the motional ground state and in the n=1 Fock state. In the linear quadrupole rf-trap with 700 kHz trap frequency along the symmetry axis (2 MHz in radial direction) the minimum ion spacing is more than 5 micron for up to 4 ions. We are able to cool two ions to the ground state in the trap and individually address the ions with laser pulses through a special optical addressing channel.Comment: Proceedings of the ICAP 2000, Firenz

Insect eggs induce a systemic acquired resistance in Arabidopsis.

Although they constitute an inert stage of the insect's life, eggs trigger plant defences that lead to egg mortality or attraction of egg parasitoids. We recently found that salicylic acid (SA) accumulates in response to oviposition by the Large White butterfly Pieris brassicae, both in local and systemic leaves, and that plants activate a response that is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here we discovered that natural oviposition by P. brassicae or treatment with egg extract inhibit growth of different Pseudomonas syringae strains in Arabidopsis through the activation of a systemic acquired resistance (SAR). This egg-induced SAR involves the metabolic SAR signal pipecolic acid, depends on ALD1 and FMO1, and is accompanied by a stronger induction of defence genes upon secondary infection. Although P. brassicae larvae showed a reduced performance when feeding on Pseudomonas syringae-infected plants, this effect was less pronounced when infected plants had been previously oviposited. Altogether, our results indicate that egg-induced SAR might have evolved as a strategy to prevent the detrimental effect of bacterial pathogens on feeding larvae

Feasibility of therapeutic pneumoperitoneum in a large animal model using a microvaporisator

Background: Multimodal therapy is used increasingly in advanced gastrointestinal tumors. Potential benefits of using an intraoperative adjuvant therapy during laparoscopy for cancer have been documented in animal studies. The aim of this study was to develop a device that could deliver such an intraoperative drug therapy. Methods: We developed a micropump suitable for minimally invasive surgery procedures that allowed microdroplets of therapeutic substance to be distributed into the pneumoperitoneum (CO2), creating a "therapeutic pneumoperitoneum.” A closed-loop control system regulates drug delivery according to the gas flow. In vitro, the micropump is able to aerosolize various aqueous and ethanol solutions, including cytostatic and bacteriostatic drugs and adhesionmodulating agents. The size of the microdroplets has been optimized to prevent visual artifacts. Results: The micropump was tested in an animal model (pig). The system was inserted into a 5-mm trocar. After insufflation of a 12-mm CO2 pneumoperitoneum, laparoscopic sigmoid colon resections could be performed with no special difficulties. No fog developed, and no systemrelated complication was observed. At autopsy, the active principle was distributed to all exposed peritoneal surfaces. Conclusions: As opposed to conventional peritoneal washing, therapeutic pneumoperitoneum reaches the entire peritoneal surface, allowing an optimal drug distribution. Drug diffusion into the tissues is enhanced by the intraperitoneal pressure. Precise determination of the instantaneous and total drug quantity is possible. Therefore, this drug delivery system has several advantages over conventional irrigation. Its potential domains of application are locoregional cancer therapy, prevention of port-site recurrences, immunomodulation, analgesia, peritonitis, and prevention of postoperative adhesion

Terrestrial–marine connectivity: patterns of terrestrial soil carbon deposition in coastal sediments determined by analysis of glomalin related soil protein

Glomalin, an arbuscular mycorrhizal protein component of soil, can be used as an indicator of terrigenous-derived carbon. We measured glomalin in sediments using the terrestrial end-member as a reference in four coastal settings: (1) intertidal seagrass meadows distributed over a rainfall gradient, (2) sediments inshore and offshore from the mouth of a river, (3) coastal coral reefs at various distances from the shore, and (4) intertidal wetlands with varying levels of groundwater influence. Across the rainfall gradient, glomalin in seagrass meadow sediments increased at sites with high mean annual rainfall during the wet season (r(2) = 0.27; F-1,F-29 = 5.75; p = 0.029). Glomalin decreased in inshore river sediments (terrestrial) to offshore (marine) sediments (r(2) = 0.81; F-1,F-17 = 71.7;

The Measurement Bench for the LHC Spool Corrector Magnets in Industry

The LHC accelerator will be equipped with more than 3500 superconducting spool corrector magnets. CERN has awarded the contract for the series production and testing of these corrector magnets to industry. Magnetic field measurements are done at the factory. Dedicated magnetic measurement benches have been built to test these corrector magnets in the resistive state at room temperature. The benches allow to measure the strength of the main field, normal and skew harmonics, the magnetic axis position and orientation of the main field with respect to the mechanical reference points of the magnet. This paper presents the objectives, a description and the performances obtained with the benches during first measurements at industry