Temperatures In Excess Research Articles

The dissolution rates of naturally altered basalts at pH 3 and 120 °C: Implications for the in-situ mineralization of CO2 injected into the subsurface

Due to their widespread distribution in the Earth's crust, it seems likely that altered basalts could be targeted for CO2 storage via subsurface carbon mineralization. To assess the potential efficiency of this approach, the steady state release rates of major elements from a suite of altered basalts have been measured at pH 3, 120 °C, and far from equilibrium conditions. The altered basalt samples have chemical compositions close to that of fresh basalt, but their mineralogy varies due to their alteration either at the Earth's surface or hydrothermal conditions at temperatures up to 250 °C. The studied altered basalts contain variable amounts of primary plagioclase and pyroxene, and substantial secondary phases including quartz, zeolites, epidote, chlorites and clay minerals. Despite their differing mineralogy, the steady-state element release rates of all the altered basalts are similar to each other when normalized to geometric surface area. These rates, however, are one to three orders of magnitude slower than corresponding release rates of basaltic glass and fresh crystalline basalt, depending on the element and on whether the rates are normalized to initial BET or geometric surface area. If present in small amounts in the altered basalts, calcite dissolves rapidly in the acidic reactive fluids, and does not contribute to the measured steady-state calcium release rates. Taken together, the results of this study indicate that altered basalt formations can provide sufficient divalent cations for subsurface carbon mineralization. As the element release rates of these altered basalts are lower than those of basaltic glass or fresh crystalline basalt, efforts to carbonate subsurface altered basalts may be best targeted at systems having temperatures in excess of 100 °C to compensate for the lower reactivity of these rocks.

Friends in Arms: Flavonoids and the Auxin/Cytokinin Balance in Terrestrialization.

Land plants survive the challenges of new environments by evolving mechanisms that protect them from excess irradiation, nutrient deficiency, and temperature and water availability fluctuations. One such evolved mechanism is the regulation of the shoot/root growth ratio in response to water and nutrient availability by balancing the actions of the hormones auxin and cytokinin. Plant terrestrialization co-occurred with a dramatic expansion in secondary metabolism, particularly with the evolution and establishment of the flavonoid biosynthetic pathway. Flavonoid biosynthesis is responsive to a wide range of stresses, and the numerous synthesized flavonoid species offer two main evolutionary advantages to land plants. First, flavonoids are antioxidants and thus defend plants against those adverse conditions that lead to the overproduction of reactive oxygen species. Second, flavonoids aid in protecting plants against water and nutrient deficiency by modulating root development and establishing symbiotic relations with beneficial soil fungi and bacteria. Here, we review different aspects of the relationships between the auxin/cytokinin module and flavonoids. The current body of knowledge suggests that whereas both auxin and cytokinin regulate flavonoid biosynthesis, flavonoids act to fine-tune only auxin, which in turn regulates cytokinin action. This conclusion agrees with the established master regulatory function of auxin in controlling the shoot/root growth ratio.

A Mantle Plume Beneath South China Revealed by Electrical Conductivity Obtained from Three-Dimensional Inversion of Geomagnetic Data.

A three-dimensional electrical conductivity model of the mantle beneath South China is presented using the geomagnetic depth sounding method in this paper. The data misfit term in the inversion function is measured by the L1-norm to suppress the instability caused by large noises contained in the observed data. To properly correct the ocean effect in responses at coastal observatories, a high-resolution (1° × 1°) heterogeneous and fixed shell is included in inversion. The most striking feature of the obtained model is a continuous high-conductivity anomaly that is centered on ~(112° E, 27° N) in the mantle. The average conductivity of the anomaly appears to be two to four times higher than that of the global average models at the most sensitive depths (410-900 km) of geomagnetic depth sounding. Further analysis combining laboratory-measured conductivity models with the observed conductivity model shows that the anomaly implies excess temperature in the mantle. This suggests the existence of a mantle plume, corresponding to the Hainan plume, that originates in the lower mantle, passes through the mantle transition zone, and enters the upper mantle. Our electrical conductivity model provides convincing evidence for the mantle plume beneath South China.

Impact of climate change on lemon (Citrus limon L.) production in eastern Bangladesh

The study was conducted to assess the impact of climate change on lemon production at Sreemangal of eastern Bangladesh as the area is moderately vulnerable to climate change. The study sample consisted of 80 randomly selected lemon growers who were interviewed and the data were collected to identify their perceptions, social characteristics, and the impact of climate change on lemon production. The results of the survey indicated that the grower’s perception of climate change was impactful as a majority of growers claimed increased annual precipitation (48.8%), increased summer temperature (48.8%), and reduced winter temperature (46.3%). In the case of extreme events, 56.3% of growers mentioned that the intensity of storms has increased in the last 5 years (2015-2019) and 58.8% of lemon growers said that the intensity of rainfall had increased substantially. However, in terms of environmental hazards, the findings indicate that excess rainfall, pest infestation, cloudy skies, hail storms, and drought are the major problems in lemon production. On the surface, overcast skies cause most of the damage to lemon production. Apart from this, soil fertility, pests, diseases, excess temperature, crop sowing time, maturity period, and drought had a significant impact on lemon production in the study area. From the correlation coefficient table, it appears that many socioeconomic characteristics were also influenced by the impact of climate change on lemon production. In the study area, there is a positive significant relationship between changes in lemon production and changes in environment and risks. The lemon crop requires moderate temperatures and average rainfall for improved production. Bangladesh J. Agri. 2022, 47(2): 64-70

Determination of the Optimum Operating Conditions and Geometrical Dimensions of the Plate Fin Heat Sinks Using Teaching-Learning-Based-Optimization Algorithm

Abstract Electronic devices must be effectively cooled for long-term reliability and safe operation. It is essential to determine operating conditions and optimum dimensions of cooling devices in terms of device weight, space, cost, and sound limits. Plate fin heat sinks (PFHSs) are frequently used for cooling electronic devices. Optimum thermal designs of PFHSs are explored in this study using a teaching-learning-based-optimization (TLBO) algorithm where entropy generation (S˙gen) minimization, profit factor (J) maximization, base plate temperature excess (θb) minimization, total mass (mass) minimization, and total volume (volume) minimization are the objective functions of the constrained single-objective optimization problems. For further investigations of the entropy generation minimization method, three different optimization problems are also studied: minimization of thermal resistance (Rth), minimization of pressure drop (ΔP), and minimization of pumping power (W˙pump). Each optimization problem is subjected to a constraint, namely, temperature excess of base plate temperature (θb) should be lower than 10 K. Four optimization variables are considered which are the number of plate fins (N), freestream velocity (Vf), the thickness of the fin (tfin), and height of the fin (Hfin). Optimum configurations belonging to the different optimization problems are compared, and the effect of each optimization variable on the objective functions is discussed in detail. It is found that one can obtain optimum operating conditions and geometrical dimensions of the PFHSs according to the design objective, i.e., minimum mass requirement, space limitation, minimum base plate requirement, etc. As a result, the optimum designs of the studied cases are different which are superior to each other in terms of design targets.

Fire spread among multiple vehicles in tunnels using longitudinal ventilation

The characteristics of fire spread among multiple vehicles in tunnels using longitudinal ventilation were investigated by analyzing the experimental data from a series of fire tests in a 1:15 scale tunnel. Further, a simple theoretical model for gas temperature in a tunnel with multiple fire sources was proposed and used in analysis of the experimental data. The results showed that, for objects (wood piles) placed at a same separating distance downstream of the fire, the fire spread occurred faster and faster along the tunnel. Validation of the simplified temperature model for multiple fire sources was made against both model and full-scale tunnel fire tests. The model was further used to predict the critical conditions for fire spread to the second and third objects. Comparisons with the test data showed that average excess temperature of 465 K (or an equivalent incident heat flux of 18.7 kW/m2) could be used as the criterion for fire spread, and this was verified further by other model-scale tests and full-scale tests. The results showed that the critical fire spread distance monotonously increases with the heat release rate, and decreases with the tunnel perimeter. For multiple fire sources with equivalent heat release rates, as the separation distance between the first two fire sources increases, the critical fire spread distance from the second fire source to the third fire source decreases, but the total fire spread distance from the first fire source to the third one increases. If the total heat release rate at the site of a downstream fire source is greater than that at the former fire source, the critical fire spread distance becomes longer.

AUSTRAL WRIGHT 5083

Abstract Austral Wright 5083 is a wrought, non-heat-treatable, aluminum-magnesium-manganese-chromium alloy (5xxx series). It has the highest strength of the non-heat-treatable alloys but is not recommended for use at temperatures in excess of 65 °C (150 °F). It is among the most widely used aluminum alloys for marine applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: Al-493. Producer or source: Austral Wright Metals.

Comparisons of Structured Surface Floors for Pool Boiling Enhancement at Low Heat Fluxes: Hands-On Learning Setup for Heat Transfer Classroom

Various enhanced surfaces have been proposed over the years to improve boiling heat transfer. This paper introduces an experimental setup designed for boiling demonstration in the graduate-level Heat Transfer course. The pool boiling performance of water under atmospheric pressure of 1.025 bar is investigated by using several structured surfaces at heat fluxes of 28 and 35 kW/m2. Surfaces with holes, rectangular grooves, and mushroom fins are manufactured by an NC-controlled vertical milling machine. The heat flux versus excess temperature graph is plotted by using thermocouple measurements of water and base temperatures of the boiling vessel. The separation, rise, and growth of individual vapor bubbles from the surface during boiling were recorded with a digital camera. The results for the plain surface are compared to the Rohsenow correlation. The enhancement of heat transfer coefficient (h) ranged between 15% - 44.5% for all structured surfaces. The highest heat transfer coefficient enhancement is observed between 41% - 56.5% for holed surface-3 (405 holes) compared to the plain surface. The excess temperature dropped around 29% - 34% for holed surface-3 (405 holes) compared to the plain surface. The heat transfer coefficient increases as the spacing between channels or holes decreases. While the bubbles on holed and mushroomed surfaces were spherical, the bubbles on the flat and grooved surfaces were observed as formless. The suggested economical test design could be appropriate to keep students focused and participating in the classroom.

Экспериментальное исследование запорного устройства вихревого типа

Modern technologies for obtaining materials include chemical reactions occurring at excess pressure and high temperatures accompanied by phase transitions. Such processes take place in devices for sulfuric acid production, heterogeneous catalysis and chemical synthesis, in devices for drying, burning and melting bulk materials and other furnaces. The technological processes under consideration are accompanied by the loading of bulk material into the internal cavity of the apparatus – the reactor. In this case, the material loading window is sealed by a mechanical locking device which opens at the stage of the technological process, accompanied by loading of raw materials into the reactor. In this case, the air-tightness of the reactor is broken and gases can be released into the environment, which poses a threat to the health of the working staff and the environment as a whole. The article focuses on an experimental study of the gas-dynamic characteristics of the air flow at the exit of the annular nozzle of a vortex-type pneumatic shut-off device. The paper analyzes the methods for studying hydro-gas-dynamic parameters of vortex flows with justification for the choice of the study method. It also describes the laboratory setup and instrumentation for the study. The results of the research include the distribution of total pressure from the axial component of velocity and its structure. We also constructed the diagrams of the distribution of the axial component of the active air velocity and obtained a refined velocity distribution along the nozzle radius. The results of the study indicate the operability of the device and can be used in the physical and mathematical description of the working process of a vortex pneumatic shut-off device, as well as in the development of methods for optimal profiling of the device.

Thermodynamic assessment of gasification and pyrolysis of marine algae to produce hydrogen-containing gas

The article gives a thermodynamic assessment of modes of gasification and pyrolysis of algae of gross formulation C1H1.66O1.4 with obtaining hydrogen gas. The authors investigate the modes of air gasification and pyrolysis of algae at pressures of 0.1 MPa and 1 MPa with varying the fuel excess ratio and temperatures. In the case of gasification at a pressure of 0.1 MPa the hydrogen and carbon monoxide concentration increases with an increase of the fuel excess ratio (φ) from 2 to 10 and at φ = 10 and T = 1000 K reaches 25.95 mole % and 27.84 mole %, respectively. An increase in temperature from 1000 K to 1300 K leads to a decrease in the amount of hydrogen and an increase in carbon monoxide in the gaseous products. An increase in the operating pressure from 0.1 to 1 MPa at a gasification temperature of 1000 K leads to the formation of a small amount of methane (~ up to 5 mole %), a decrease in the mole content of hydrogen and carbon monoxide in the final products, and also to the formation of coke (at φ≥7), which we can use as a target product. The caloric value of the gases produced is higher in the pyrolysis of algae than in its gasification. The pressure increase at 1300 K has almost no effect on the equilibrium composition of the products in the gaseous products.

Particle films improve photosynthesis of citrus trees under excess irradiance by reducing leaf temperature

High irradiance and increased air temperature during extreme weather conditions affect tree crops and impact the yield and quality of fruits. Moreover, flowering and fruit set of Citrus are likely impaired by UV radiation and/or reduced carbon assimilation, which increase reactive oxygen species production and damage the leaf photosynthetic apparatus. Particle coating films sprayed on leaves have been offered as a way to minimize crop losses due to the climate change scenario, even though the extent of leaf protection is not characterized. We evaluated the use of two protective films on the oxidative stress and leaf photosynthesis of sweet orange trees exposed to varying daylight levels. Trees were maintained under full sun light, sprayed or not (control) with kaolin or calcium carbonate, and under reduced irradiance using either aluminum shade cloth 50% or anti-UV transparent plastic. Kaolin or calcium carbonate reflected 20%-30% of the incident light on the leaf surface compared to leaves not sprayed and under full sunlight. Leaves with coating exhibited improved CO2 assimilation and photosystem II efficiency, and lower leaf temperatures over time. In addition, the coating protected leaves against excess irradiance due to dissipation of excess energy into the photosynthetic apparatus (NPQt). Nonenzymatic mechanisms for UV protection, such as carotenoids, were higher in full sun control plants than in leaf-coated plants. Comparable responses were observed on trees maintained covered either by the cloth or the plastic film. Finally, we conclude that the use of suspension particles mitigates the harmful effects of excess UV irradiance and temperature in sweet orange trees.

An Environmentally Friendly and Cost-Effective Route to LiNi0.5Mn1.5O4 Crystals: Structure, Morphology Evolution, and Electrochemical Properties

A green and economical process based on the room-temperature solid-state reactions is developed to synthesize LiNi0.5Mn1.5O4, and the effects of sintering temperature and lithium excess on the structure, morphology and performance are investigated in detail. The measurements reveal that the performance of the LiNi0.5Mn1.5O4 is highly dependent on the crystal morphology and integrity which are significantly influenced by the sintering temperature, and the results demonstrate that well-crystallized octahedral-like crystals with superior electrochemical performance can be readily synthesized by the new developed route at a moderate sintering temperature of 800 °C with a small lithium excess of 3%.

The Influence of Climate Variability on the Watermelon Production in Zanzibar

Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Currently, there is either no or scant information that describes the influence of climate changes and variability to watermelon production in Zanzibar. Thus, this study aimed to determine the influence of climate variability on the quantity of watermelon production in Zanzibar. The study used both primary and secondary datasets, which include the anecdotal information collected from interviewers’ responses from four districts of Unguja and Pemba, and climate parameters (rainfall, maximum and minimum temperature (Tmax and Tmin) acquired from Tanzania Meteorological Authority (TMA) at Zanzibar offices. Pearson correlation was used for analyzing the association between watermelon production and climate parameters, while paired t-test was applied to show the significance of the mean differences of watermelon and climate parameters for two periods of 2014-2017 and 2018-2021, respectively. Percentage changes were used to feature the extent to which the two investigated parameters affect each other. The anecdotal responses were sorted, calculated in monthly and seasonal averages, plotted and then analyzed. Results have shown a strong correlation (r = 0.8 at p ≤ 0.02, and r = 0.7) between watermelon production, Tmax and rainfall during OND, especially in Unguja, as well as Tmin during JJA (i.e. r = - 0.8 at p ≤ 0.02) in Pemba. Besides, results have shown the existence of significant differences between the means of watermelon production and climate parameter for the two stated periods, indicating that the climate parameters highly affects the watermelon production by either enhancing or declining the yields by 69% - 162% and 17% - 77%, respectively. Moreover, results have shown that respondents were aware that excess temperature intensity during dry periods can lead to high production costs due number of soil and other environmental factors. Besides the results have shown that OND seasonal rainfall and MAM Tmax had good association with watermelon production in Unguja while JJA Tmin declined the production in Pemba. Thus, the study concludes that seasonal variability of climate parameter has a significant influence on the watermelon production. The study calls for more studies on factors affecting watermelon production (e.g. soil characteristics, pest sides and manure), and recommends for climate based decision making on rain fed agricultural yields and routine monitoring of weather information.

Deep solar ALMA neural network estimator for image refinement and estimates of small-scale dynamics

Context. The solar atmosphere is highly dynamic, and observing the small-scale features is valuable for interpretations of the underlying physical processes. The contrasts and magnitude of the observable signatures of small-scale features degrade as angular resolution decreases. Aims. The estimates of the degradation associated with the observational angular resolution allows a more accurate analysis of the data. Methods. High-cadence time-series of synthetic observable maps at λ = 1.25 mm were produced from three-dimensional magnetohydrodynamic Bifrost simulations of the solar atmosphere and degraded to the angular resolution corresponding to observational data with the Atacama Large Millimeter/sub-millimeter Array (ALMA). The deep solar ALMA neural network estimator (Deep-SANNE) is an artificial neural network trained to improve the resolution and contrast of solar observations. This is done by recognizing dynamic patterns in both the spatial and temporal domains of small-scale features at an angular resolution corresponding to observational data and correlated them to highly resolved nondegraded data from the magnetohydrodynamic simulations. A second simulation, previously never seen by Deep-SANNE, was used to validate the performance. Results. Deep-SANNE provides maps of the estimated degradation of the brightness temperature across the field of view, which can be used to filter for locations that most probably show a high accuracy and as correction factors in order to construct refined images that show higher contrast and more accurate brightness temperatures than at the observational resolution. Deep-SANNE reveals more small-scale features in the data and achieves a good performance in estimating the excess temperature of brightening events with an average of 94.0% relative to the highly resolved data, compared to 43.7% at the observational resolution. By using the additional information of the temporal domain, Deep-SANNE can restore high contrasts better than a standard two-dimensional deconvolver technique. In addition, Deep-SANNE is applied on observational solar ALMA data, for which it also reveals eventual artifacts that were introduced during the image reconstruction process, in addition to improving the contrast. It is important to account for eventual artifacts in the analysis. Conclusions. The Deep-SANNE estimates and refined images are useful for an analysis of small-scale and dynamic features. They can identify locations in the data with high accuracy for an in-depth analysis and allow a more meaningful interpretation of solar observations.

Вільна конвекція — дослідження регулярного теплового режиму в різних шарах по висоті рідини

The rate of cooling (heating) of experimental liquids is investigated separately for five thermocouples located at different heights of the experimental probe. Research is carried out on an experimental stand in the system "environment I — body II", where "environment I" is water, and "body II" is the investigated liquid medium in a thin metal cylindrical shell under conditions of free convection. The rate of cooling (heating) is studied for test liquids: water, sunflower oil, distilled glycerin. The analysis of cooling (heating) processes during free convection of non-stationary heat exchange is carried out. This paper presents research carried out on an experimental stand, which consists of an external metal vessel, containing the environment with a temperature of t1, an internal cylindrical metal vessel containing an experimental liquid medium with a temperature of t2. Accordingly, probes with five thermocouples are placed in hot and cold liquids to take temperature values at a fixed time Non-stationary heat conduction processes occur during heating or cooling of bodies, substances, gaseous media and are accompanied by a change in enthalpy. Non-stationary and stationary processes of body heating due to the internal heat source, the electric heater, are considered in laboratory practice to determine the thermophysical properties of materials, bodies of substances and where cooling occurs due to the surrounding air. The analysis of the excess temperature, carried out separately for each thermocouple, placed along the height of the cylindrical volume, shows that the linearity of the dependence Ln ϑ = f(τ) is preserved, while the influence of free convection on the value of m is manifested. The value of m depends on the height of the liquid layer in which the temperature is measured.

Laboratory investigations on the thermo-mechanical behaviour of an energy pile group operated in heat release mode

Compared to the single energy pile, the thermo-mechanical behavior of pile group become more complicated due to mutual influences of different piles. A model test device of pile group with 2 × 2 layout was built to study the thermo-mechanical characteristics of pile group with different number of energy piles, inlet temperatures and connection forms of buried pipes. The results show that compared to single energy pile, the energy pile group mode will lead to the decrease of heat exchange performance and the increase of pile tip soil pressure and pile head displacement. But, the side friction and axial force of pile will decrease as a result of pile group effect. Meanwhile, increasing the inlet temperature can enhance heat exchange characteristics of pile group, but it will also result in the increase of the soil temperature, pile head displacement, pile tip soil pressure, pile shaft axial force and pile side friction. Additionally, reducing the number of energy piles in pile group can improve the heat exchange rate per unit pile depth, but the total heat transfer amount of energy pile group will decrease. With the increase of the number of energy pile in pile group, the temperature change and pile head displacement of the pile increase, but the pile side friction and pile body axial force decrease. Under current experimental conditions, the pile head displacement and pile body axial force in parallel connection mode are larger than those in series connection modes, and the pile body excess temperature is the smallest in parallel mode of four energy piles and the largest in series mode of four energy piles. For the series connection mode, the heat exchange performance, pile body excess temperature, pile head displacement and pile body axial force gradually decrease along the series direction due to the decrease of temperature change.

Analysis of a borehole ground heat exchanger with shape-stabilized phase change material backfill

GSHP (ground source heat pump) is a popular green building technology that utilizes renewable energy sources, but its efficiency can decrease significantly due to heat accumulation in soil. The borehole ground heat exchanger (BGHE) with shape-stabilized phase change material (SSPCM) backfill is a novel method to alleviate temperature fluctuation owing to better thermophysical properties. However, relevant experimental studies are still in scarcity and the impacts of backfill material on the soil temperature remain to be explored. This study conducted an experimental measurement on the soil temperature of a BGHE with SSPCM (expand graphite adsorbed paraffin) and sand backfill. A numerical model is established accordingly to be validated by the experimental results, in order to provide additional simulations on the sand-SSPCM mixture to identify the system performance and cost-effectiveness under different mass ratios of SSPCM. The experimental results show that SSPCM can effectively mitigate temperature fluctuations, especially closer to the heat source. The excess temperature difference is up to 10 °C near the heater wall. Compared to sand backfill, the sand-SSPCM backfill area's outside also maintains a steady temperature for a longer time during the cooling process. The numerical model couples the line heat source model of the BGHE with the validated phase change process. The simulation results found that the heat influence radius under the novel backfill was reduced by 16.5% after one operating cycle. Furthermore, after a 14 h shutdown, the novel backfill temperature is higher than the traditional backfill in the backfill area. The impact of various SSPCM mass mixing ratios indicates that a higher mass ratio can help reduce temperature variations, but the larger the mass ratio the less cost-effective it becomes. The optimum mass ratios are dependent on different parameters used as objectives.

Full-scale experimental and numerical study of smoke spread characteristics in a long-closed channel with one lateral opening

This paper aims to study the characteristics of smoke flow in a long-closed channel with one lateral opening at one end. A series of full-scale experiments with different longitudinal positions and heat release rates of fire sources were carried out. And, the corresponding numerical simulations were conducted to help explain the law of smoke flow field. The characteristics of the smoke spread on both sides of the fire source, the thermal plume distribution within the channel, and the maximum ceiling excess temperature were analyzed. Results show that the existence of the end walls in the long channel causes the smoke to accumulate, which further results in the smoke settlement going through three stages. The lateral opening causes a significant difference of smoke flow and other characteristics from the channel with both ends open. When the fire source approaches the closed end without opening, the vertical fire-induced plume inclines to the closed end because of the asymmetrical air supplementation. Due to the limited air supply, the combustion will change to ventilation-controlled as the fire source heat release rate increases. The maximum ceiling excess temperature is higher than that with both ends open and is basically not influenced by fire positions studied in this work. It has been verified that the dimensionless maximum ceiling excess temperature of the smoke is also proportional to the dimensionless heat release rate. This study can provide a reference for fire prevention and smoke exhaust strategies for long channels.

Efficient biodiesel production from waste cooking oil by fast co-immobilization of lipases from Aspergillus oryzae and Rhizomucor miehei in magnetic chitosan microcapsules

To achieve an efficient and cost-effective conversion from waste cooking oil (WCO) to biodiesel, a facile one-pot co-immobilization of Aspergillus oryzae lipase (AOL) and Rhizomucor miehei lipase (RML) was developed by rapid encapsulation of magnetic chitosan microcapsules. The encapsulation process was accomplished by self-assembly of negatively charged magnetic nanoparticles (citrate modified Fe3O4) on ionic cross-linked chitosan-citrate aggregates containing lipases. Integrating Tween 80 bio-imprinting of lipases, the co-immobilized AOL@RML (co-im Tween 80-AOL@RML) achieved a significant increase in activity and reached 98.5 % biodiesel yield under optimal conditions, which was 1.3 and 1.6 times higher than that of single immobilized AOL and RML, respectively. Notably, owing to the beneficial synergistic impact of methanol-tolerable AOL and thermal-stable RML, co-im Tween 80-AOL@RML displayed superior activity over single lipase counterparts under excess methanol and variable temperatures. The co-im Tween 80-AOL@RML could maintained 96 % activity after 3 cycles of biodiesel production; however, showed an obvious inactivation after continued reuse. Moreover, methanol-induced denaturation of lipases and glycerol-caused agglomeration of the magnetic nanoparticles during continued transesterification were ascertained by fourier transform infrared analysis and scanning electron microscopy. This study provides new pathways for constructing multi-lipase co-immobilzation as well as an economical and effective biocatalyst for biodiesel production from WCO.

The in-depth study of Romanian prehistoric ceramics: Late Neolithic/Eneolithic pottery and clay materials from the Foeni Tell-Orthodox cemetery in Timiş county

The study aims to analyze pottery samples from the archaeological site Foeni Tell – Orthodox Cemetery, a late Neolithic & early Eneolithic multi-stratified site (three phases, covering the period 4720-4457 cal BC), also inhabited during the Early Bronze Age and Middle Ages. The site is located on the western edge of Foeni (Timiș county, Romania), on the eastern bank of the Timișaț river. The analyzed samples come from 20 pottery shards, belonging to the Foeni cultural group (4920/4675–4580/4460 cal BC, corresponding to the later period of the Vinča culture, from the end of phase C to the end of phase D), and are representative of the categories (black, red, orange, painted) and types (fine, semi-fine, coarse) pottery associated with the cultural group; also analyzed were soil samples from the site. Complementary techniques were used in the analysis (TG/DTG, FT-IR, SEM, EDX, XRF, XRD and LIBS) to ascertain details regarding production technology and origin of the raw materials used in making the pottery. Results indicate the pottery was based on a high plasticity illite and montmorillonite paste, alongside albite, microcline, analcime, with heavy use of quartz and mica as temper. The clay composition shows an obvious link between the pottery and the local sampled source, implying the local production of Foeni type pottery. The firing temperature is uniform in Foeni pottery, estimated in the range of 550–600 °C, with a maximum firing temperature of 600 °C, with slightly higher temperatures for painted wares, of up to 620–630 °C, with a maximum temperature of 650 °C. The sole exception has an estimated firing temperature in excess of 900 °C.