Selected Crater and Small Caldera Lakes in Alaska: Characteristics and Hazards

This study addresses the characteristics, potential hazards, and both eruptive and non-eruptive role of water at selected volcanic crater lakes in Alaska. Crater lakes are an important feature of some stratovolcanoes in Alaska. Of the volcanoes in the state with known Holocene eruptive activity, about one third have summit crater lakes. Also included are two volcanoes with small caldera lakes (Katmai, Kaguyak). The lakes play an important but not well studied role in influencing eruptive behavior and pose some significant hydrologic hazards. Floods from crater lakes in Alaska are evaluated by estimating maximum potential crater lake water volumes and peak outflow discharge with a dam-break model. Some recent eruptions and hydrologic events that involved crater lakes also are reviewed. The large volumes of water potentially hosted by crater lakes in Alaska indicate that significant flowage hazards resulting from catastrophic breaching of crater rims are possible. Estimates of maximum peak flood discharge associated with breaching of lake-filled craters derived from dam-break modeling indicate that flood magnitudes could be as large as 103–106 m3/s if summit crater lakes drain rapidly when at maximum volume. Many of the Alaska crater lakes discussed are situated in hydrothermally altered craters characterized by complex assemblages of stratified unconsolidated volcaniclastic deposits, in a region known for large magnitude (>M7) earthquakes. Although there are only a few historical examples of eruptions involving crater lakes in Alaska, these provide noteworthy examples of the role of external water in cooling pyroclastic deposits, acidic crater-lake drainage, and water-related hazards such as lahars and base surge.

Ship course control system with compensation of external disturbance on steering gear

The article focuses on developing synthesis methods for automatic heading control systems for the rudder-controlled sea vessel. The solution of the problem of vessel heading control is carried out in the conditions of heavy sea. The disturbing effect of the external water environment causes the vessel yawning, which results in exceeding activity of the steering gear. This leads to its increased wear and loss in the longitudinal speed of the vessel. To reduce the wave effect there has been supposed an approach based on the additionally introduced internal model of the ship dynamics. The given approach is aimed at improving the operation of the steering gear in rough seas. To implement the proposed algorithm, changes are made to the original system by introducing an internal model in parallel to the control object and modifying the feedback channel of the control system. To describe the sea vessel dynamics there is used the 1st order Nomoto model, the steering gear model is implemented in accordance with the imposed speed limits and the rudder shift value. Wave disturbance is close to harmonic disturbance. The identification of the parameters of the internal model can be carried out in advance, both by maneuvering tests and by the process of operation. Numerical simulations carried out in the MATLAB/Simulink system confirmed the advantage of the proposed approach. The synthesis of control in a system with an internal model makes it possible to significantly neutralize the influence of wave disturbance. The modifications introduced to the original control system help to improve functioning of the steering gear, significantly reducing the number of rudder shifts during operation.

Experimental Study on the Permeation and Migration Rules of Pressurized Water in Textile-Reinforced Concrete (TRC)

As a new type of repairing and reinforcing material, textile-reinforced concrete (TRC) is often used to improve mechanical properties and durability of offshore, port, and hydraulic structures in the corrosive environment. In order to investigate how to quantify the permeability performance of TRC under external pressurized water, standard concrete permeability tests, nuclear magnetic resonance (NMR) tests, and scanning electron microscope (SEM) tests were conducted. These tests considered the effects of fiber grid size, Tex content, and water–cement ratio on the impermeability of TRC. Experimental results show that water gathers around the fiber bundles and migrates upwards along the longitudinal fiber under external water pressure and seeps out from the upper surface of the concrete specimen. Furthermore, based on the concentric annular slit flow theory and hydropower similarity principle, this study established a formula for the permeability of TRC and the calculated values are in good agreement with the experimental values.

APPLICATION OF HUMATIC REAGENT FOR DUST DESTRUCTION AND DEGASATION IN MASS EXPLOSIONS

The work is devoted to the coverage of the results of research and industrial tests of environmental efficiency of water replacement in internal and external hydraulic wells in the quarries of mining enterprises for humic reagent [1]. Scientific and technical problem of determining environmental efficiency, solved by conducting in 2020 by the Research Mining Institute (NDGRI KNU) industrial research in the conditions of PJSC "Northern Mining and Processing Plant" (PJSC "PIVNGZK", Kryvyi Rih) kg / dust3 kg rocks) and gas formation (kg / kg BP) during mass explosions with the use of water in the holes in comparison with the use of humic reagent. Dust- binding and degassing properties of humate-based reagents are confirmed by the results of research and industrial tests conducted by the Research Institute of Occupational Safety and Ecology in the Mining and Metallurgical Industry (NDIBPG KNU) in 2019 by conducting experiments with pre-wetting blocks before conditions of quarries of Inguletskyi, Central and Northern GZK [1]. According to the results of experimental and industrial tests, it is substantiated that the efficiency of the use of humic reagent in the external water hammer in comparison with the use of technical water was: dust suppression increases by 20.0%; neutralization of carbon monoxide - 59.4%; neutralization of nitrogen oxides - 55.1%.

New Horizons of Well Bonding: Cement Expansion in Absence of Water Access

Zonal isolation for primary cementing is generally of concern when there is potential for gas migration. The challenge for the industry is to achieve a long-term annular cement seal and prevent gas migration. This paper focuses on the problem of ensuring sufficient bulk expansion of set cement without access to external water and optimizing the cement slurry formulation. The approach to solving this problem is creative and simple within the industry. One of the reasons for wellbore gas migration and inter-connected flows can be due to cement shrinkage over time. This study focuses on laboratory testing of an expanding cement system in the absence of water and analysis of test results of novel the cement system in terms of its implementation on well with high gas migration potential. The cement system behavior will also be described in terms of rheological, filtration and mechanical properties and compared to conventional expanding cement slurries. This approach can be used to improve cement bonding with the aim of minimizing future remedial jobs. Several approaches were implemented to achieve noticeable expansion in anhydrous media. One of the methods showed it was feasible to achieve 1.27% linear expansion in set cement without external water contact, while linear expansion in the presence of water was 0.78%. This method uses the addition of sodium chloride (NaCl) and while it has been previously described in literature, no practical design/testing directions have been given. The study identified the most effective concentration of sodium chloride required for set cement expansion without water availability. The study described how other cement system properties permitted better results in terms of placement quality of highly salt-saturated cement. Overall, complex laboratory test results provide evidence of effective linear expansion in set cement in the absence of external water. The optimization of cement slurry properties was focused on obtaining optimal thickening time, rheology and compressive strength, which was complicated by the presence of a high concentration of sodium chloride. An expanding cement system was successfully tested in the absence of water showing positive linear expansion. A new approach for testing expanding cement systems in the absence of water was introduced how excessive linear expansion could be compromised with compressive strength development. The research results have shown that the use of NaCl additive in high concentrations in high SVF self-healing systems provided improved performance when aiming for effective linear expansion in set cement in the absence of water.

Volcano-air-sea interactions in a coastal tuff ring, Jeju Island, Korea

The Holocene tuff ring of Songaksan, Jeju Island, Korea, is intercalated with wave-worked deposits at the base and in the middle parts of the tuff sequence, which are interpreted to have resulted from fair-weather wave action at the beginning of the eruption and storm wave action during a storm surge event in the middle of the eruption, respectively. The tuff ring is overlain by another marine volcaniclastic formation, suggesting erosion and reworking by marine processes because of post-eruption changes of the sea level. Dramatic changes of the chemistry, accidental componentry, and ash-accretion texture of the pyroclasts are also observed between the tuff beds deposited before and after the storm invasion. The ascent of a new magma batch, related to the chemical change, could not be linked with either the Earth and ocean tides or the meteorological event. However, the changes of the pyroclasts texture suggest a sudden change of the diatreme fill from water-undersaturated to supersaturated because of an increased supply of external water into the diatreme. Heavy rainfall associated with the storm is inferred to have changed the water saturation in the diatreme. Songaksan demonstrates that there was intimate interaction between the volcano and the environment.

Pencegahan Kerak Dan Korosi Umpan Ketel Uap Di PG Mojo Sragen

Air umpan ketel uap adalah air yang disuplai ke dalam ketel untuk di rubah menjadi uap. Air Umpan Ketel (Boiler Feed Water) Secara umum yang akan digunakan adalah air yang tidak mengandung unsur kalsium (Ca) yang dapat menyebabkan terjadinya endapan yang dapat membentuk kerak pada ketel uap, air yang tidak mengandung unsur yang dapat menyebabkan korosi terhadap ketel dan sistem penunjangnya dan juga tidak mengandung unsur yang dapat menyebabkan terjadinya pembusaan terhadap air ketel uap. Tujuan dari penelitian ini adalah untuk mengetahui pencegahan kerak dan korosi air umpan ketel uap dalam mendukung proses produksi gula agar proses produksi dapat berjalan dengan efektif di pabrik gula mojo sragen menggunakan cara pencegahan kerak dan korosi dengan internal water treatment dan external water treatment. Hasil yang diperoleh dari penelitian ini menunjukkan bahwa penyebab dari masalah pada ketel uap yoshimine dengan tekanan kerja 17kg/jam yaitu karena terbentuknya kerak di dalam ketel yang di sebabkan terutama oleh kalsium (Ca) dan magnesium (Mg) pada dinding pipa yang dapat menghambat proses penghantaran panas serta terjadinya korosi terhadap logam ketel, sepanjang aliran air umpan dan aliran kondensat yang disebabkan oleh gas oksigen yang terlarut dalam air dan solusinya dengan external water treatmen merupakan perawatan yang dilakukan terhadap air sebelum masuk kedalam ketel uap untuk menghilangkan kandungan mineral dan gas tertentu pada air dan internal water treatmen untuk menyempurnakan apa yang telah dilakukan oleh perawatan eksternal, sehingga masalah yang mungkin terjadi didalam ketel uap dan jalur kondensat dapat diminimalkan

Proteins as Hair Styling Agents

The perming of hair is a common styling procedure with negative impact on the overall properties of the hair fibers. Usually, this process uses harsh chemicals to promote the disruption of disulfide bonds and the formation of new bonds to change the shape of hair. Here, we explored bovine serum albumin (BSA), silk fibroin (SF), keratin and two fusion recombinant proteins (KP-UM and KP-Cryst) as new perming agents. A phosphate buffer prepared at different pH values (5, 7 and 9) was used to apply the proteins to virgin Asian hair, and a hot BaByliss was used to curl the hair fibers. To assess the potential of the protein formulations for hair styling, the perming efficiency and the perming resistance to wash were measured. Furthermore, the fiber water content was evaluated to assess if the proteins protected the hair during the styling process. Despite all of the proteins being able to assist in the curling of Asian hair, the best perming efficiency and perming resistance to wash results were observed for BSA and keratin. These proteins showed perming efficiency values close to that measured for a commercial perming product (chemical method), particularly at pH 5 and 9. The increase in the hair’s internal and external water contents revealed a protective effect provided by the proteins during the application of heat in the styling procedure. This study shows the potential of proteins to be used in the development of new eco-friendly hair styling products.