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Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage

Di era pandemi Covid-19, kebutuhan akan refreshing menjadi salah satu kebutuhan pokok yang dapat menimbulkan kebahagiaan sehingga dapat mendorong terbentuknya imunitas tubuh yang baik. Selain hemat biaya, daerah wisata ruang terbuka menjadi pilihan utama bagi para penikmat wisata untuk menikmati pemandangan alam dengan tetap memperhatikan protokol kesehatan dan meminimalisir resiko tertular Covid-19. Yang tak kalah penting, daerah wisata terbuka ini tentunya juga harus mengakomodir kebutuhan penikmatnya untuk mengabadikan momen berwisatanya melalui foto sehingga desain kawasan wisata nantinya merupakan daerah yang instagrammable dan menarik untuk dikunjungi. Hal-hal inilah yang mendorong tim pengabdian masyarakat untuk membantu masyarakat di Dusun Langkap Barat, Kec. Burneh, Kab. Bangkalan untuk merencanakan wisata sawah untuk mengembangkan potensi sumber daya alam serta sumber daya manusia di desa tersebut, sehingga usaha kecil dan menengah di desa ini dapat semakin berkembang dan nantinya kawasan wisata sawah ini dapat dinikmati oleh masyarakat luas dan mendorong tumbuhnya imunitas masyarakat yang semakin baik. Simulasi untuk melihat kekuatan struktur jembatan untuk spot swafoto dilaksanakan menggunakan perangkat lunak. Struktur dirancang sesuai dengan kondisi di lapangan. Dari hasil simulasi, diperoleh defleksi maksimum sebesar 0,23 mm dengan beban enam orang. Defleksi ini masih dalam kategori aman. Kawasan wisata sawah di Desa Langkap telah dibangun dengan tiga spot swafoto.

Hydrides of the AB2 Laves type alloys (A=Zr, Ti; B = transition metal – Fe, Co, Ni, Mn, Cr, V) have been extensively studied as materials for the storage of gaseous hydrogen. They contain up to 4 H atoms/formula unit AB2, thus achieving reversible H storage capacities in the range between 1.5 and 2.0 wt% H and offering high rates of hydrogen charge and discharge, thus making them suitable for designing efficient hydrogen stores operating at ambient conditions. In the present study, we performed an experimental study and modeling of the thermodynamics and the kinetics of interaction in the AB2-hydrogen system. The experimental data was collected by studying a model alloy with a composition Ti0.15Zr0.85La0.03Ni1.126Mn0.657V0.113Fe0.113. Hydrogen absorption and desorption were studied in a volumetric Sieverts type apparatus at isothermal conditions using a single-step change/discharge and stepwise methods. The results obtained from the model simulation show that the reaction follows the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, with the value of exponent n = 1–1.25 for absorption and 1 for desorption. This indicates that the rate-limiting hydrogen absorption and desorption steps are jointly governed by hydrogen diffusion and grain boundary nucleation of alpha-solid solution and beta-hydride. The activation energies for both hydrogen absorption and desorption decrease along with increasing hydrogen content in the hydride.

Due to its low cost and recycle-ability, the lead-acid battery is widely used in mobile and stationary applications. Despite much research on lead-acid batteries, the effect of charging voltage on the degradation mechanism requires further investigation. In particular, the origin of cycle life degradation remains unclear. In the present work, by using electrochemical tests and materials characterization, we studied the effect of charging voltage at voltages slightly higher than the open-circuit potential (OCP) i.e., 103-107% OCP, on the battery life cycle. The highest degradation was observed at 105% OCP charging voltage. Based on the materials characterization results, we found that the degradation of a lead-acid battery is influenced by the amount of hard sulfate and the sulfate particles' size.

In-situ (on-site) metallography has been proven as a method to assess metallurgical condition of material without damaging the material (Non Destructive Testing). However in this case, in-situ metallography must be completed together with several analysis to prevent metallography misinterpretation. This paper also provides an overview of inspection technique continuity, together with result from in-situ (on-site) and laboratory analysis.Water wall tube in-situ metallography was conducted during periodic inspection of a 200 MW Steam Power Plant Boiler. It was found another phase beside ferrite and pearlite. The phase is in horizontal direction and suspected as micro crack, delta ferrite or retained austenite.The further investigation was carried out by performing laboratory analysis including: metallography, scanning electron microscopy (SEM) equipped with EDX (Energy-dispersive X-ray spectroscopy) and hardness test.Result of the investigation showed that the phase was oxide as a corrosion product derived from tube surface and hot gas reaction during combustion. The oxide is identical as dry corrosion oxide, without liquid electrolyte. The oxide was only found on fireside tube surface. It also can be described that the fireside tube was over exposed to high temperature as shown the change lamellar pearlite to globular spheroidized pearlite.

One of the main components in a gas turbine for the power plant is the turbine blade. The turbine blade lifetime depends on materials, operation, and maintenance. A prominence reason for accelerate turbine blade degradation is caused by the failure of the thermal barrier coating (TBC). In the present work, we studied the failure of TBC on the 1st stage turbine blade. A scanning electron microscope, optical light microscope, and X-Ray diffraction were used for samples examination. The analysis results showed that the TBC of first stage turbine blades is a plasma-water type sprayed and consists of 7 wt. % yttria-stabilized zirconia (YSZ). Mechanism of separation in the TBC layer is caused by thermal fatigue due to thermal differences expansion between the TBC and the thermally grown oxide (TGO), thereby causing tensile stress and compression on the TBC. The pressure causes micro-cracks on the top coat lead to the separation of the TBC top coat.

The combined cycle power plant (PLTGU) is the second largest percentage of electrical production method which is 26% of all electrical production technology in Indonesia. One of the components in combined cycle power plant is the heat-recovery steam generator (HRSG), which serves as heat-exchanger between hot gasses from gas turbine cycle and water from steam turbine cycle. There are four stages on HRSG, preheater, economizer, evaporator, and superheater. In the present work, there is a case of thinning on a bend tube preheater which exceeds the tolerance limits, therefore the purposes of this research determine the cause of failure and determine the failure mechanism on bend tube preheater. Thinning of bend tube preheater occurred due to corrosion from both the inside surface and outside surface. Corrosion that occurred on the inside surface of bend tube preheater caused by a reaction between water and metal surface of the tube. Corrosion on the outside surface could be happen caused by a reaction between the hot gas and metal surface of the tube. Largest thinning rate occurred on bend area of bend tube preheater caused by deformation itself, it induces local reduction of breakdown potential.

Medan magnet dapat membantu proses ionisasi pada bahan bakar, sehingga bahan bakar saat proses pembakaran dapat mudah mengikat oksigen. Pengikatan oksigen pada bahan bakar secara stoikiometri menyebabkan pembakaran lebih sempurna, sehingga torsi dan daya pada mesin dapat meningkat. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh pemasangan magnet 800 gauss terhadap torsi, daya, dan konsumsi bahan bakar spesifik motor bensin 150 CC. Penelitian ini dilakukan dengan membandingkan prestasi mesin motor bensin merk Honda Verza CW 150 CC yang dipasang magnet 800 Gauss merk X-Power pada saluran bahan bakar dengan tanpa dipasang magnet 800 Gauss merk X-Power. Setiap pengujian dilakukan pada putaran mesin 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, dan 7000 rpm. Metode yang digunakan adalah secara eksperimen di Laboratorium Efisiensi dan Konversi Energi. Hasil penelitian menunjukkan bahwa dengan menggunakan magnet 800 gauss terjadi peningkatan torsi maksimal sebesar 0,59%, dan peningkatan daya maksimal sebesar 1%.