The arsenic spreading over thallus of Saccharina latissima of different habitats of the Barents Sea

The algae Saccharina latissima (Phaeophyceae) and bottom sediment were studied in two places of its habitat in the Zelenetskaya Bay of the Barents Sea: 1) in the zone of shipping traffic and ship parking (ZST&SP) and 2) algae plantations (AP) - the background part of the bay. According to the results of scanning electron microscopy and micro-X-ray spectral analysis, an active new formation of framboidal pyrite, iron oxides-hydroxides, and salt crystals were founded in the bottom sediment in the ZCST&SP of the bay. In the structure of the rhizoids of the thallom algae, inclusions of bottom sediment particles were revealed. The ICP MS method showed that the arsenic content in the S. latissima thallom significantly exceeds its level of presence in the bottom sediment. The maximum content of arsenic in algae from both habitats is determined in the rhizoids, and the lowest in the young part of the plate (meristem). The bottom sediment and thallom of S. latissima from the ZCST&SP contain two to three times more arsenic than the algae on the plantation.

Thermal Performance Analysis of a Newly Designed Circular Firewood Boiling Salt Stove

Different biomass stoves are introduced and distributed among people living in rural and urban areas, especially in developing countries. For salt crystal production in Thailand’s rural north-eastern area, open fire stoves are used in domestic and small productive activities. Their thermal efficiency is very low for converting heat into utilization energy. A new stove with a circular configuration was designed and constructed to consider its thermal efficiency and economics, which were compared with those from a traditional and an improved traditional stove. The obtained thermal efficiency of the newly designed stove was 14.77% higher than that of the improved stove and 81.45% higher than that of the traditional stove. For the same initial saline volume, the final amounts of salt crystals and salt flowers obtained from the newly designed stove was higher compared with those obtained from the improved stove and the traditional stove, respectively, resulting in a 69.25% shorter payback period.

Analysis on Material Characteristics of Restored Areas with Mortar and Basis of Surface Deterioration on the Stupa of State Preceptor Jigwang from Beopchensaji Temple Site in Wonju, Korea

The Stupa of State Preceptor Jigwang from Beopcheonsa Temple Site in Wonju (National Treasure) is a representative stupa of the Goryeo Dynasty, with outstanding Buddhist carvings and splendid patterns, clearly indicating its honoree and year of construction. However, it was destroyed by bombing during the Korean War (1950-1953) and repaired and restored with cement and reinforcing bars in 1957. The surface condition of the original stone shows long-term deterioration due to the m ortar used in past restorations. In order to identify the exact causes of deterioration, the m ortar and surface contaminants on the original stone were analyzed. Portlandite, calcite, ettringite, and gypsum from the mortar were identified, and its ongoing deterioration was observed through pH measurements and the neutralization reaction test. Analysis of surface contaminants identified calcite and gypsum, both poorly water-soluble substances, and their growth in volume among rock-forming minerals was observed by microscopy. Based on those results, semi-quantitative analysis of Ca and S contents significantly influencing the formation of salt crystals was conducted using P-XRF to analyze the basis of surface deterioration, and cross-validation was performed by comparing the body stone affected by the mortar and the upper stylobate stone unaffected by the mortar. Results indicate that the elements are directly involved in the surface deterioration of the body stone.

Salt-rejecting rGO-coated melamine foams for high-efficiency solar desalination

Solar-driven interfacial desalination has been emerged as a promising water treatment technology to generate drinkable water out of seawater. The accumulated salt crystals generated from seawater, however, have adverse effects on solar-driven interfacial evaporation. In this work, we prepared a salt-rejecting reduced graphene oxide (rGO) foam by depositing rGO particles on a hydrophilic melamine foam for solar desalination. Benefitting from the intrinsic porous microstructure and hydrophilicity, the rGO-coated melamine foam has sufficient wettability to draw water to the evaporation region, leading to rapid replenishment of water and simultaneously avoiding salt precipitation. Based on the rGO-coated melamine foam, the interfacial evaporation system can achieve a steady-state evaporation efficiency of 89.6% under a solar flux of 1 kW m−2 and has good durability under one sun over 12 h. With the high solar-to-thermal conversion efficiency and excellent long-term stability, this interfacial evaporation system exhibits the potential of commercial seawater desalination. Graphic abstract

Rochelle Salt-Based Ferroelectric and Piezoelectric Composite Produced with Simple Additive Manufacturing Techniques

More than one century ago, piezoelectricity and ferroelectricity were discovered using Rochelle salt crystals. Today, modern societies are invited to switch to a resilient and circular economic model. In this context, this work proposes a method to manufacture piezoelectric devices made from agro-resources such as tartaric acid and polylactide, thereby significantly reducing the energy budget without requiring any sophisticated equipment. These piezoelectric devices are manufactured by liquid-phase epitaxy-grown Rochelle salt (RS) crystals in a 3D-printed poly(Lactic acid) (PLA) matrix, which is an artificial squared mesh which mimics anatomy of natural wood. This composite material can easily be produced in any fablab with renewable materials and at low processing temperatures, which reduces the total energy consumed. Manufactured biodegradable samples are fully recyclable and have good piezoelectric properties without any poling step. The measured piezoelectric coefficients of manufactured samples are higher than many piezoelectric polymers such as PVDF-TrFE.

Weathering Features of A Five-Story Stone Pagoda Compared To Its Quarrying Site In Geumgolsan Mountain, Korea

Understanding the long- and short-term weathering features according to rock type is very important for maintaining the original form of stone heritages. In this study, the material characteristics of a deteriorated five-story stone pagoda were compared with those of fresh rocks from its quarrying site at nearby Geumgolsan Mountain, Korea to diagnose the degree of damage and develop a comprehensive interpretation of the weathering mechanism. The stone pagoda was built from lithic tuff comprising pumice and phenocrysts such as quartz, K-feldspar, plagioclase, and mica based on plagioclase substrates; the mineralogical and geochemical characteristics are similar to those of the fresh rocks. The lithic tuff of the stone pagoda demonstrated a low ultrasonic velocity of 2863 m/s and a high water absorption rate and porosity of 9.5% and 19.2%, respectively, which are poorer than the physical properties of the fresh rocks (i.e., ultrasonic velocity of 3336 m/s, water absorption rate of 8.65%, and porosity of 17.83%). The lithological characteristics and physical properties demonstrated a considerable influence on the weathering and stability of the stone pagoda. In particular, fragments of relatively weak pumice detached from the original rock to form cavities of various sizes. These cavities introduced moisture within the rock, which produced oxides and hydroxides of iron and manganese. In addition, contaminants such as dust, salt crystals, clay minerals, and microorganisms adhering to the surface of the stone pagoda accelerated its physical, chemical, and biological weathering. The results of this study will be important for realizing the stable and long-term conservation of the five-story stone pagoda at Geumgolsan Mountain.

New Aspects on the Direct Solid State Polycondensation (DSSP) of Aliphatic Nylon Salts: The Case of Hexamethylene Diammonium Dodecanoate

The direct solid state polymerization (DSSP) of hexamethylene diammonium dodecanoate (PA 612 salt) was investigated for two different salt grades, fossil-based and bio-based. Aliphatic polyamide salts (such as PA 612 salt) are highly susceptible to solid melt transition (SMT) phenomena, which restrain the industrial application of DSSP. To that end, emphasis was given on reactor design, being the critical parameter influencing byproduct diffusion, amine loss and inherent DSSP kinetics. Experiments took place both at the microscale and the laboratory scale, in which two different reactors were tested in terms of bypassing SMT phenomena. The new reactor designed here proved quite successful in maintaining the solid state during the reaction. Scouting experiments were conducted in order to assess the effect of critical parameters and determine appropriate reaction conditions. Fossil-based PA 612 products proved to have a better end-group imbalance in comparison to bio-based ones, which is critical in terms of achieving high molecular weight. Finally, a real DSSP process was demonstrated, starting from PA 612 salt crystals and ending with PA 612 particles.

Rochelle Salt Based Ferroelectric and Piezoelectric Composite Produced with Simple Additive Manufacturing Techniques

One century ago, ferroelectricity and then piezoelectricity were discovered using Rochelle salt crystals. Today, modern societies are invited to switch towards a resilient and circular economy model. In this context, this work proposes a method to manufacture piezoelectric devices made from agro-resources such as tartric acid and polylactide significantly reducing the energy budget without requiring any sophisticated equipement. These piezoelectric devices are manufactured by liquid phase epitaxy grown Rochelle salt (RS) crystals into a 3D printed poly(Lactic acid) (PLA) matrix being the artificial squared meshes which mimic the natural wood anatomy. This composite material can easily be produced in any fablab with renewable materials and at low processsing temperatures, reducing then the total energy consumed. Manufactured biodegradable samples are fully recyclable and have good piezoelectric properties without any pooling step. The measured piezoelectric coefficients of manufactured samples are higher than many piezoelectric polymers such as PVDF-TrFE.

METHODS FOR BOTTOM BOREHOLE ZONE TREATMENT IN WELLS CHECHEN REPUBLIC

Состояние призабойной зоны пласта (ПЗП) имеет для интенсификации притока очень важное значение. По мере эксплуатации скважины постепенно ухудшаются фильтрационно-емкостные свойства пласта. В качестве кольматанта могут быть механические примеси (кварцевый песок, кристаллы солей, смолы, асфальтены, незакрепившийся пропиант, частицы бурового раствора и т.д.). Авторами предложены технологии и технические средства проведения обработок пласта. The state of the bottomhole formation zone (BHZ) is very important for the stimulation of the inflow. As the well is operated, the reservoir properties gradually deteriorate. Mechanical impurities (quartz sand, salt crystals, resins, asphaltenes, loose propant, particles of drilling mud, etc.)can be used as a bridging agent. The authors proposed technologies and technical means for carrying out treatment of the formation

Geological controls on brine discharge in Itumbula Salt Dam within the Rukwa Rift in Momba District, Tanzania

The Itumbula salt dam of the Rukwa Rift Basin is a depression formed through extraction of spring-derived salt crystals. Brine yield by springs which is the primary cause of significant amounts of salt in the dam required further geological investigations to understand yield controls. In this study, detailed field geological investigations in the salt dam and its surroundings were conducted to ascertain brine discharge controls. These included documentation of lithology and surface manifestations of brine deposition. Geophysical methods (i.e. magnetic and electric surveys) for studying geologic structures associated with brine deposits, and laboratory analysis of cations and anions (e.g. chlorides, bicarbonates or sulphates) essential to characterize composition of waters were also performed. The information on the springs discharge rate was retrieved from the previous studies. The magnetic profile revealed a very low magnetic anomaly across the salt dam, trending NW to SE direction, which is interpreted to be the main structure that controls fluid movements in the dam. Electric resistivity survey results delineated a low resistivity body in the central part of the dam interpreted as porous formation with saline water. Hydro-chemistry of the hot spring brines indicated high levels of sodium and chloride ions contents than magnesium, calcium, potassium, sulphate, and carbonate and bicarbonate ions, interpreted to be mature water with minimal water mixing. The structurally controlled brines of approximately 2.5 kg/s are discharged in the study area. Keywords: Geologic Structures, Brine, Salt Production, Momba, Rukwa Basin.