Corrosion Studies on Ss-321 in Natrium-Hydroxide Solution

Corrosion Studies On Ss-321 In Natrium-Hydroxide Solution. Experimental corrosionstudies on commercial SS-321 have been carried out. The experiments were carried out in a sodiumhydroxide medium with a concentration variation of 0.4 M. 0.5 M, 0.6 M, and0.7Mcorresponding topHvalues of 13.6, 13.69, 13.78, and 13.84 respectively. The experiments were carried out using a type ofM-273 EG&Gpotentiostat/galvanometer test instrument. The post-corrosion samples' microstructure wereanalyzed with the aid of EDS (energy dispersive spectroscopy) equipped SEM instrument to detect thepresence of any viable corrosion byproducts. Forfurther verification x-ray diffraction method was alsoused to detect any possible emerging corrosion byproducts on the samples' surfaces correlated to theSEM-EDS result. Experimental results confirm that A1SI-321 commercial alloys immersed in a natriumhydroxide corrosion medium with a variation of concentration experience very little or almost nocorrosion, so that according to the so-called Fontana's criteria these test-materials turn out to have anexcellent resistance toward natrium hydroxide corrosion. This is also evidenced by the very low corrosionrate value measured in this study. EDS study and X-ray diffraction results indicate that the possibleensuing corrosion byproducts are iron oxides, chromeoxides and silicon oxides

Ekplorasi Dan Penangkaran Bibit Rumput Laut (Eucheuma Cottonii) Di Perairan Teluk Ekas Lombok Timur

Tujuan dari penelitian ini adalah untuk mendapatkan bibit Eucheuma cottonii dari habitat aslinya di perairan Teluk Ekas dan menangkarkan bibit tersebut. Penelitian ini dilakukan di Teluk Ekas Lombok Timur Nusa Tenggara Barat. Metode yang digunakan pada penelitian ini adalah metode ekplorasi di perairan Teluk Ekas serta mendeskripsikan hasil pengamatan. Eucheuma cottonii yang berhasil di temukan dan di ekslporasi dari perairan Teluk Ekas, memiliki ciri morfologi lebih banyak memiliki bakal talus sehingga tampak sebagai duri-duri pada thalus. Talus keras dan kaku serta berwarna coklat kehijauan. Eucheuma cottoniidijumpai menempel pada batuan dan karang yang berada pada kisaran kedalaman 1 meter sampai dengan 1,5 meter. Eucheuma cottoniimenempel kuat pada subtrat sehingga sulit untuk diambil dengan tangan, harus menggunakan pisau atau alat pemotong lainnya. Eucheuma cottoniidapat ditangkarkan dan tumbuh dengan baik di perairan Teluk Ekas

Sintesis Paduan Co-cr Menggunakan Metode Ultrasonik

Paduan Co-Cr merupakan material tahan suhu tinggi dan tahan korosi. Penelitian ini bertujuan mensistesis serbuk paduan Co-Cr dengan metode ultrasonik, kemudian dilanjutkan dengan proses sintering dalam kapsul kaca kuarsa. Iradiasi ultrasonik yang digunakan pada frekuensi 20 kHz dan amplitudo 40 % dengan komposisi Co : Cr sebesar 80 : 20.Waktu perlakuan sonikasi adalah selama 0 jam, 3 jam, 6 jam, 12 jam, 24 jam, dan 48 jamdalam larutan etanol. Setelah sonikasi selama 48 jam, fasa FCC dari Co mulai bertransformasi menjadi fasa HCP. Perlakuan ultrasonik terhadap campuran Co-Cr juga memberikan efek pengurangan ukuran partikel. Parameter kisi serbuk setelah ultrasonikasi 48 jam adalah: untuk HCP-Co a = b = 0,25074 nmdan c = 0,40699 nm, untuk FCC-Co a = b = c = 0,35411nm, dan untuk BCC-Cr a=b=c=0.28827 nm. Perlakuan ultrasonik selama 48 jam menhasilkan pembentukan paduan Co-Cr dengan persentasi berat sebesar 25,2124. Hasil sintering padatan Co-Cr menunjukkan parameter kisi HCP-Co memiliki nilai yaitu a = b = 0,25230 nm dan c=0,41223 nm, dan FCC-Co a = b = c = 0,35232 nm. Terbentuknya microalloying CoCr diindikasikan dari hasil EDS, teramati partikel yang mempunyai komposisi Co : Cr = 71,25 : 24,45. Paduan Co-Cr yang terbentuk setelah sintering pada 1300 oC adalah sebesar 15,33416 %berat

Wide dynamic range tranimpedance amplifier using peaking capacitance technique for high speed optical wireless communication system

In the high speed optical communication, the requirement of designing the new optical transceivers is quite challenging due to the bandwidth, noise and environmental conditions for designing the optical transceivers. The optical transceivers design is also challenging because of weak optical signal at the frond-end amplifier. In this paper, the optical transceivers via an optical preamplifier for optical wireless communication is designed. The designed system offers the improved performance in terms of bandwidth and gain compared to existing optical transceivers. It is defined that using the designed system, a high bandwidth of 2.114GHz at 29.72dB gain is achieved. The designed optical transceiver provides the bandwidth enhancement utilizing the peaking inductor and capacitor

Integrated Open Loop Resonator Filter Designed with Notch Patch Antenna for Microwave Applications

This paper presented the design of integrated open loop resonator bandpass filter with notch type antenna for the use in microwave applications. Chebyshev type filter is selected as the filter characteristics and cascaded design with the antenna to produce a single module, Integrated Filter Antenna (IFA). Special feature of the antenna is the implementation of notch on the patch antenna to improve the efficiency. IFA is then simulated in electromagnetic simulation tool, Agilent Advance Design System (ADS) version 2016 and measured using R&S Vector Network Analyzer. It shows that the proposed IFA produced good measured return loss >-30dB with both vertical and horizontal gain of 9.11dBi and 8.01dBi respectively

Integrated Open Loop Resonator Filter Designed with Notch Patch Antenna for Microwave Applications

This paper presented the design of integrated open loop resonator bandpass filter with notch type antenna for the use in microwave applications. Chebyshev type filter is selected as the filter characteristics and cascaded design with the antenna to produce a single module, Integrated Filter Antenna (IFA). Special feature of the antenna is the implementation of notch on the patch antenna to improve the efficiency. IFA is then simulated in electromagnetic simulation tool, Agilent Advance Design System (ADS) version 2016 and measured using R&S Vector Network Analyzer. It shows that the proposed IFA produced good measured return loss >-30dB with both vertical and horizontal gain of 9.11dBi and 8.01dBi respectivel

Detour spectrum and detour energy of conjugate graph complement of dihedral group

Study of graph from a group has become an interesting topic until now. One of the topics is spectra of a graph from finite group. Spectrum of a finite graph is defined as collection of all distinct eigenvalues and their algebraic multiplicity of its matrix. The most related topic in the study of spectrum of finite graph is energy. Energy of a finite graph is defined as sum of absolute value of all its eigenvalues. In this paper, we study the spectrum and energy of detour matrix of conjugate graph complement of dihedral group. The main result is presented as theorems with complete proof

Mapping human genetic diversity in Asia

Asia harbors substantial cultural and linguistic diversity, but the geographic structure of genetic variation across the continent remains enigmatic. Here we report a large-scale survey of autosomal variation from a broad geographic sample of Asian human populations. Our results show that genetic ancestry is strongly correlated with linguistic affiliations as well as geography. Most populations show relatedness within ethnic/linguistic groups, despite prevalent gene flow among populations. More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations

Coercive Pressures and Anti-corruption Reporting: The Case of ASEAN Countries

This paper aims to investigate the extent of anti-corruption reporting by ASEAN companies and examine whether coercive factors influence the level of disclosure. The authors adopt indicators from the Global Reporting Initiative version 4.0 to measure the extent of anti-corruption disclosures in 117 companies’ reports. Informed by a coercive isomorphism tenet drawn from the institutional theory, the authors propose that several institutional factors influence the extent of their voluntary disclosures. The findings reveal that a large degree of variability difference between the average levels of anti-corruption disclosure in Thailand (434 words) and the Philippines (149 words). The dependence on government tenders and foreign ownership are associated with the level of disclosure. Surprisingly, the United Nation Global Compact membership is not a significant determinant of anti-corruption reporting. This signifies that the membership in the international initiative does not correspond to individual company’s commitment to disclose anti-corruption information. In spite of significant efforts undertaken by global organizations to combat corruption, the level of anti-corruption disclosure is significantly different among the four countries under study. The disclosure of sensitive information such as the confirmed incidences of corruption cases requires careful consideration by the top management as it is subjected to legal implications and reputational risks. Thus, impression management can complement the coercive pressure in explaining the level of anti-corruption reporting. This study is among the first studies which explores the association between coercive factors and the level of anti-corruption disclosure in ASEAN region