Pemanfaatan Lignin Dari Lindi Hitam (Black Liquor) Sebagai Inhibitor Korosi Besi

Corrosion is one of the important problems faced by advanced industry groups. The corrosion process occurs naturally and can not be prevented entirely, and often unexpectedly taking place beyond the planned prediction. Various processes can be done to prevent corrosion, one of them by using corrosion inhibitor process. A corrosion inhibitor is the process by which a substance is added to the environment so as to reduce the risk of corrosion to the metal. The inhibitor used is derived from lignin obtained from waste from the pulp and paper industry named black liquor. In this study used lignin variation with percent weight (0, 3, 5, 8 gram) and time variation with time spent (2, 4, 6 hours). The most optimal inhibition efficiency occurs in iron which is soaked with time 4 hours and with lignin concentration 8 g / L that is equal to 73,6842105

Synthesis of silver and gold nanoparticles-enzyme-polymer conjugate hybrids as dual-activity catalysts for chemoenzymatic cascade reactions

Novel hybrids containing silver or gold nanoparticles have been synthesized in aqueous media and at room temperature using enzymes or tailor-made enzyme-polymer conjugates, which directly induced the formation of inorganic silver or gold species. The choice of pH, protein, or bioconjugate strongly affected the final metallic nanoparticles hybrid formation. Using Candida antarctica lipase (CALB) in a solution, nanobiohybrids containing Ag2O nanoparticles of 9 nm average diameter were obtained. The use of tailor-made bioconjugates, for example, the CALB modified with dextran-aspartic acid polymer (Dext6kDa), resulted in a nanobiohybrid containing smaller Ag(0)/Ag2O nanoparticles. In the case of nanobiohybrids based on gold, Au(0) species were found in all cases. The Au-CALB hybrid contained spherical nanoparticles with 18 nm average diameter size, with a minor range of larger ones (>100 nm) while the AuNPs-CALB-Dext6kDa hybrid was formed by much smaller nanoparticles (9 nm, minor range of 22 nm), and also nanorods of 20-30/40-50 nm length. Using Thermomyces lanuginosus lipase (TLL), apart from the nanoparticle formation, nanoflowers with a diameter range of 100-200 nm were obtained. All nanobiohybrids maintained (dual) enzymatic and metallic activities. For instance, these nanobiohybrids exhibited exquisite dual-activity for hydrolysis/cycloisomerization cascades starting from allenic acetates. By merging the transition metal reactivity with the inherent lipase catalysis, allenic acetates directly converted to the corresponding O-heterocycles in enantiopure form catalysed by AgNPs-CALB-Dext6kDa, taking advantage of a kinetic resolution/cyclization pathway. These results showed the high applicability of these novel hybrids, offering new opportunities for the design of novel reaction cascades.Peer reviewe

Enzymatic Bromocyclization of alpha- and gamma-Allenols by Chloroperoxidase from Curvularia inaequalis

Vanadate-dependent chloroperoxidase from Curvularia inaequalis catalyzes 5-endo-trig bromocyclizations of alpha-allenols to produce valuable halofunctionalized furans as versatile synthetic building blocks. In contrast to other haloperoxidases, also the more challenging 5-exo-trig halocyclizations of gamma-allenols succeed with this system even though the scope still remains more narrow. Benefitting from the vanadate chloroperoxidase's high resiliency towards oxidative conditions, cyclization-inducing reactive hypohalite species are generated in situ from bromide salts and hydrogen peroxide. Crucial requirements for high conversions are aqueous biphasic emulsions as reaction media, stabilized by either cationic or non-ionic surfactants.Peer reviewe

PENGARUH KETERAMPILAN DAN PENGALAMAN KERJA TERHADAP KEMAMPUAN KERJA KARYAWAN PADA PT. PILAR UTAMA ASIA MEDAN

ABSTRACTEmployees in a company have diverse abilities, seen from the sectors or divisions they occupy. Developments in the field of skills and work experience have made the company more sensitive in improving the quality of its resources. There are also human resources or employees who occupy certain positions in the company have the ability in accordance with the required requirementsThe problem in this study is whether there is an influence of skills on the work ability of employees at PT. Main Pillar of Asia Medan, is there any influence of work experience on the work ability of employees at PT. Main Pillars of Asia Medan, and whether there is an influence of skills and work experience on the work ability of employees at PT. Asia's Main Pillars of Medan.The research method used is associative method. Associative research is research that aims to determine the relationship of two or more variables. In this study used as many as 40 respondents.The results showed that based on the results of the t-test research, the value of skills t-test was 2.972> t-table = 1.68709, meaning Ho was rejected and H1 was accepted. So the skills can partially affect the work ability of employees at PT. Asia's Main Pillars of Medan. Based on the results of t-test research, the value of t-work experience is 2.646> t-table = 1.68709, meaning that Ho is rejected and H2 is accepted. So work experience can partially affect the work ability of employees at PT. Asia's Main Pillars of Medan. Based on the results of the F-test research, the F-calculated value of 9.933> F-table = 3.25, it can be concluded that Ho is rejected and H3 can be accepted, namely skills and work experience together (simultaneously) simultaneously affect the work ability employees at PT. Asia's Main Pillars of Medan. It is recommended that PT. Main Pillars of Asia Medan continues to provide skills to employees because it is one of the factors to improve employee work capabilities. So that the PT. Main Pillars of Asia Medan pay more attention to the work experience that employees have at work because it is a factor that affects the work ability of employees.Keywords: Skills, Work Experience, and Work Abilit

Makna Televisi Bagi Generasi Z

Saat ini menonton televisi tidak menjadi pilihan utama bagi generasi saat ini. Di era globalilasi saat ini banya sekali media yang dipilih selain televisi. Penggunaan Televisi berbeda-beda disetiap khalayak masyarakat Beberapa orang mejadikan televisi sebagai sarana informasi, ada pulayang mejadikan televisi sebagai sarana hiburan saja . Ini memungkinkan generasi saat menggunakan televisi sebagaisarana yang mudah sesuai dengan ketertarkkannya.Televisi dapat menimbulkan berbagai dampak bagi para pemirsanya, terutama kaum generasi saat ini. Baik itu berupa dampak positif maupun dampak negatif melalui televisi, dapat menyaksikan semua tayangan yang mereka inginkan mulai dari tayangan yang layak untuk mereka konsumsi hingga tayangan yang belum sepantasnya mereka konsumsi. Pada saat ini banyak stasiun televisi yang menayangkan berbagai macam program acara yang bisa kita saksikan selama 24 jam.Penelitian ini bertujuan untuk mendeskripsikan makna televisi dikalangan generasi Z. Penelitian ini menggunakan pendekatan kualitatif dengan teknik pengumpulan data yang digunakan di penelitian ini, ada wawancara, setelah wawancara dilaksanakan, data ditulis dalam transkrip yang telah kami transkip sebelumnya. Hasil dari Selective Coding yaitu Menonton televisi, Pilihan tayangan dan Kebebasan mengendalikan remote.Hasil penelitian ini menunjukan bahwa televisi bukan menjadi pilihan utama bagi kalangan milenial untuk mendapatkan infomasi ataupun hiburan, dan remaja lebih suka sesuatu hal yang praktis dan mudah diakses seperti internet

Chemoenzymatic Hydrogen Production from Methanol through the Interplay of Metal Complexes and Biocatalysts

Microbial methylotrophic organisms can serve as great inspiration in the development of biomimetic strategies for the dehydrogenative conversion of C1 molecules under ambient conditions. In this Concept article, a concise personal perspective on the recent advancements in the field of biomimetic catalytic models for methanol and formaldehyde conversion, in the presence and absence of enzymes and co-factors, towards the formation of hydrogen under ambient conditions is given. In particular, formaldehyde dehydrogenase mimics have been introduced in stand-alone C1-interconversion networks. Recently, coupled systems with alcohol oxidase and dehydrogenase enzymes have been also developed for in situ formation and decomposition of formaldehyde and/or reduced/oxidized nicotinamide adenine dinucleotide (NADH/ NAD+). Although C1 molecules are already used in many industries for hydrogen production, these conceptual bioinspired low-temperature energy conversion processes may lead one day to more efficient energy storage systems enabling renewable and sustainable hydrogen generation for hydrogen fuel cells under ambient conditions using C1 molecules as fuels for mobile and miniaturized energy storage solutions in which harsh conditions like those in industrial plants are not applicable.Peer reviewe

The QUEST initiative anemia study in ESRD: rationale and study protocol

No abstrac

Self-Sufficient Formaldehyde-to-Methanol Conversion by Organometallic Formaldehyde Dismutase Mimic

The catalytic networks of methylotrophic organisms, featuring redox enzymes for the activation of one-carbon moieties, can serve as great inspiration in the development of novel homogeneously catalyzed pathways for the interconversion of C-1 molecules at ambient conditions. An imidazolium-tagged arene-ruthenium complex was identified as an effective functional mimic of the bacterial formaldehyde dismutase, which provides a new and highly selective route for the conversion of formaldehyde to methanol in absence of any external reducing agents. Moreover, secondary amines are reductively methylated by the organometallic dismutase mimic in a redox self-sufficient manner with formaldehyde acting both as carbon source and reducing agent