Temperature Values Research Articles

On the size- and shape-dependence of integral and partial molar Gibbs energies, entropies, enthalpies and inner energies of solid and liquid nano-particles

In this paper the size- and shape dependences of 8 different integral and partial molar thermodynamic quantities are derived for solid and liquid nano-phases, starting from the fundamental equation of Gibbs: i) The integral molar Gibbs energies of nano-phases and the partial molar Gibbs energies of components in those nano-phases, ii) The integral molar enthalpies of nano-phases and the partial molar enthalpies of components in those nano-phases, iii) The integral molar entropies of nano-phases and the partial molar entropies of components in those nano-phases, and iv). The integral molar inner energies of nano-phases and the partial molar inner energies of components in those nano-phases. All these 8 functions are found proportional to the specific surface area of the phase, defined as the ratio of its surface area to its volume. The equations for specific surface areas of phases of different shapes are different, but all of them are inversely proportional to the characteristic size of the phase, such as the diameter of a nano-sphere, the side-length of a nano-cube or the thickness of a thin film. Therefore, the deviations of all properties discussed here from their macroscopic values are inversely proportional to their characteristic sizes. The 8 equations derived in this paper follow strict derivations from the fundamental equation of Gibbs. Only the temperature dependent surface energy of solids and surface tension of liquids will be considered as model equations to simplify the final resulting equations. The theoretical equations are validated for the molar Gibbs energy against the experimental values of liquidus temperatures of pure lead. The theoretical equations for the molar enthalpy are validated i). Against the experimental values of dissolution enthalpy differences between nano- and macro cobalt particles in the same liquid alloy and ii). Against the size dependent melting enthalpy of nano-indium particles. In this way, also the theoretical equations for the molar entropy and molar inner energy are validated as they are closely related to the validated equations for the molar Gibbs energy and molar enthalpy.

The process and mechanism of coke gasification dissolution loss in hydrogen-rich blast furnace

Blast furnace (BF) hydrogen-rich smelting has become an important way for low-carbon ironmaking. The coke gasification dissolution loss will be accelerated by H2O generated through hydrogen reduction, which is the fundamental reason for the limited injection rate of hydrogen-rich gas in BF. The gasification dissolution loss experiments of coke were carried out under different conditions. Experimental results indicate that: The pore size of coke containing H2O is larger under the same gasification time. The quantitative relationship between pore size and gasification time, flow rate of H2O is obtained. The pore wall around the inner hole will gradually be eroded, the pore wall gradually dissolves along the edge of the inner hole. The connectivity between two pores starts from the deep layers of the pores, the pore walls in the deep layers of pores are first connected. The carbon layer spacing slightly decreases with gasification time, which indicates that the microcrystalline cells inside the coke have contracted in the vertical direction. The carbon layer stacking height shows an overall upward trend with the increase of temperature and gasification time, and it will reach a maximum value for a certain temperature. The carbon layer diameter increases with the prolongation of gasification time, the aromatic carbon layers continue to grow as gasification progresses. The dynamic model of H2O diffusion is established, the effective internal diffusion coefficients of H2O under different conditions are calculated, the diffusion ability of H2O is stronger than that of CO2. The mechanism of H2O dissolution loss of coke based on surface active sites is summarized, whether the gasification dissolution loss reaction can occur depends on whether there are active sites on the adsorbed surface. The competitive gasification always occurs vigorously at active sites, the gasification reaction between H2O and C is easier and the reaction rate is higher.

GIS-Based Agricultural Land Use Favorability Assessment in the Context of Climate Change: A Case Study of the Apuseni Mountains

With an emphasis on the effects of climate change, this study offers a thorough GIS-based assessment of land use favorability in the Apuseni Mountains. The Apuseni Mountains, a region characterized by its biodiversity and complex terrain, are increasingly vulnerable to the impacts of climate change, which threaten both natural ecosystems and human activities. The territory of 11 territorial administrative units was selected for the investigation because it shows more of an anthropogenic influence due to the migration of people to mountainous areas following the COVID-19 pandemic, which increased the amount of anthropogenic pressure in this area. Factors that describe the climate of the study area, the soil characteristics, and the morphometric characteristics of the relief were used to create a classification for the present on classes of favorability and restrictiveness for the plots of land, using a quantitative GIS model to determine the favorability of the land for the main crops and agricultural uses. The current land favorability was thus initially obtained, taking into account current temperature and precipitation values and using the SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios for the 2020–2099 time frame. The results indicate a variation in the statistical classification of the land for different favorability classes, a decrease of 4.7% for the high favorability class for pastures, an estimated decrease of 4.4% for grassland, and in the case of orchards, the situation reflects a fluctuating variation. There is a decrease of 6.4% in the case of the very low favorability class according to SSP2-4.5 (in the case of reaching an average temperature of 12.7 °C and an annual precipitation of 895 mm), and in case of high and very high favorability, there is an increase in plots falling into better high favorability classes of up to 0.7%.

Mechanical Properties and Thermal Decomposition Mechanism of Glycidyl Azide Polyol Energetic Thermoplastic Elastomer Binder with RDX Composite.

To improve the reinforcement effect between a binder and high solid filler in a propellant formula, grafting the bonding group into the binder to form a neutral polymeric is a practically novel approach to improving the interface properties of the propellant. In this work, a glycidyl azide polyol energetic thermoplastic elastomer binder with a -CN bonding group (GAP-ETPE) was synthesized, and the mechanical and thermal decomposition mechanism of GAP-ETPE with Hexogeon (RDX) model propellants were studied. The stress-strain results indicated that the tensile strength and strain of GAP-ETPE/RDX model propellants were 6.43 MPa and 32.1%, respectively. DMA data showed that the storage modulus (E') of the GAP-ETPE/RDX model propellants could increase the glass transition temperature (Tg) values, those were shifted to higher temperature with the increase in filler RDX percentages. TG/DTG showed the four decomposition stages of the decomposition process of the GAP-ETPE/RDX model propellants, and the thermal decomposition equation was constructed. These efforts provide a novel method to improve GAP-ETPE/RDX propellants mechanical property, and the thermal decomposition behavior of GAP-ETPE/RDX propellants also provided technical support for the study of propellant combustion characteristics.

Optimization of polarization spectroscopy signal for laser-frequency stabilization

Abstract We experimentally generate polarization spectroscopy (error) signals corresponding to the D2-line hyperfine transitions, F g = 2 → F e = 1 , 2 , 3 of 87Rb, and F g = 3 → F e = 2 , 3 , 4 of 85Rb, and show that the strongest error signals correspond to the closed hyperfine transitions (oscillator strength ∼ 0.7 ), F g = 2 → F e = 3 and F g = 3 → F e = 4 , respectively. We make the generated error signal robust to fluctuations in external parameters by finding optimum values for the vapor cell temperature and pump-probe intensities at two different beam diameters. We further employ these optimized error signals to directly (without the need for frequency/phase modulation) lock the laser frequency—reducing the rms drift/linewidth from ∼ 10 MHz to < 500 kHz, when measured over a ∼ 60 min duration. In addition, by comparing theoretically calculated and experimentally measured error signals for the pump intensities ranging from ∼ 0.1 I sat 0 − 10 I sat 0 (where, I sat 0 ∼ 1.6 mW cm−2 is the two-level saturation intensity for the Rb D2-line transitions), we discuss the applicability and limitations of existing numerical and analytical approaches based on a full multi-level rate equation model for polarization spectroscopy.

Heat Conduction Control Using Deep Q-Learning Approach with Physics-Informed Neural Networks

As modern systems become more complex, their control strategy no longer relies only on measurement data from probes; it also requires information from mathematical models for non-measurable places. On the other hand, those mathematical models can lead to unbearable computation times due to their own complexity, making the control process non-viable. To overcome this problem, it is possible to implement any kind of surrogate model that enables the computation of such estimates within an acceptable time frame, which allows for making decisions. Using a Physics-Informed Neural Network as a surrogate model, it is possible to compute the temperature distribution at each time step, replacing the need for running direct numerical simulations. This approach enables the use of a Deep Reinforcement Learning algorithm to train a control strategy. On this work, we considered a one-dimensional heat conduction problem, in which temperature distribution feeds a control system. Such control system has the objective of reacing and maintaining constant temperature value at a specific location of the 1D problem by activating a heat source; the desired location somehow cannot be directly measured so, the PINN approach allows to estimate its temperature with a minimum computational workload. With this approach, the control training becomes much faster without the need of performing numerical simulations or laboratory measurements.

Fuzzy Logic Model for Determining Optimal Temperature-Humidity Index Values in Dairy Farms in Temperate Climate

ABSTRACT In livestock, temperature, humidity, and Temperature-Humidity Index (THI) affect the welfare, yields, health and viability of animals. This study aimed to develop optimal temperature, humidity, and THI thresholds for dairy farms in temperate climate regions using a fuzzy logic model. THI values were calculated using three different literature-derived equations, considering different temperature and humidity situations in dairy farms. The Mamdani-type fuzzy logic method was utilized to formulate linguistic expressions for temperature, humidity, and THI values. According to the THI thresholds, the areas below the Receiver Operating Characteristic (ROC) were found to be significant (p < 0.001) in all fuzzy algorithms. The study found 100% harmony with the THI thresholds of 66 and 72 for cattle in temperate climates, but only 73.6% harmony with the threshold of 74 for cattle adapted to tropical climate. Briefly, in temperate dairy farms, the fuzzy logic revealed that the optimal temperature, humidity and THI values should be between 14–18.5°C, 65–70% and 52.5–64.5, respectively. However, further research is required to understand the impact of thresholds determined by fuzzy logic on dairy cow production and welfare.

PSVII-27 Nasal surface temperature variation before, during and after routine interventions

Abstract Routine practices such as teeth clipping (TEE), tail docking (TAI) and ear tagging (TAG) can be considered controversial due to the potential pain or stress they might cause. This study sought to evaluate how nasal surface temperature changes before, during and after each of these procedures (TEE, TAI, TAG) as performed routinely on a commercial farm. A total of 116 crossbred piglets (Landrace x Large white x Duroc Danish) from multiparous sows were used. As litters were processed, thermographic images were taken using a high-resolution handheld infrared camera FLIR T650sc (640 x 480 pixels; FLIR Systems, Wilsonville, OR) at a uniform distance of 1 m on the left side of the face. All thermal images were collected between 0900 and 1600 h. To assess procedures separately, a recovery period (12 ± 2.5 min) was allowed between procedures. Due to order differences in which procedures were implemented, the following study groups were created (procedures in brackets indicate the procedures performed prior to the procedure being assessed): TEE, (TEE+) TAI, (TEE+TAI+) TAG, TAI, (TAI+) TEE, (TAI+TEE+) TAG, TAG, (TAG+) TEE, (TAG+TEE+) TAI. Temperature values were recorded from images using FLIR Tools software 6.0 (FLIR Systems). GraphPad Prism 10.0.2 (San Diego, CA) statistical software was used to analyze the obtained data. All data were analyzed via a linear mixed model for repeated measures and Multiple comparisons were calculated using a post-hoc Tukey test (GraphPad Prism 10.0.2). There were no significant differences in Nasal surface temperature among groups at any time points (Table 1, P &amp;gt; 0.05). However, there was a significant reduction in temperature from before the procedure(s) to during and after the procedures in the TAG (P = 0.006) and the (TEE+) TAG (P &amp;lt; 0.001) groups. Changes in the surface temperature of piglets can be related to the sympathetic activity and the hypothalamic-pituitary-adrenal axis activation during the perception of a stressor, which causes a sympathetically mediated acute vasomotor response that shifts cutaneous capillary blood flow due to transient peripheral vasoconstriction. Infrared thermography recognizes such blood flow changes as a reduction in the amount of heat radiated from the skin. Indeed, the nasal surface temperature was reduced in TAG and (TEE+) TAG piglets during and after the procedure(s) which suggests these procedure groups caused a greater degree of thermal change to the piglets. Furthermore, the results suggest that infrared thermography could be a useful tool to assess the impact of routine husbandry practices on piglet welfare. Nonetheless, further research should assess infrared thermography alongside behavioral and physiological assessments to establish the relationship between surface temperature and stress during husbandry procedures.

Can rheometer be used for determination of baking stability of cocoa based filling creams

Bake stable filling creams are important for some products such as biscuits, cakes, cookies, etc. In the present study, a rheometer-based method for determining the baking stability of the cream fillings was developed considering the consistency and fluidity of the fillings after baking. For this aim, the heating and cooling process was simulated depending on the temperature of the filling reached during the baking process of cookies. Three bake-stable and three bake-unstable filling creams were obtained from the market. Rheological, textural, and baking stability analysis were performed on the samples. Change in the apparent viscosity values of the samples was observed at temperature values from 20 °C to 105 °C and from 105 °C to 30 °C using rheometer. The percentage of viscosity change at 30 °C before and after the heating process was calculated. This value for stable samples was 67%, 73% and 9%. Fluctuation observation during the measurement is also important for stability. Unstable fillings have many fluctuations in the temperature versus apparent viscosity curve as their viscosity change value was lower. The absence of fluctuations on the temperature versus viscosity graph indicates the stability of the filling creams. The findings of the study indicated that a rheometer can be used as an effective tool for determining the baking stability of the creams with minimal effort, labor, sample requirement, and time.

471 The use of infrared imaging of piglets to assess ocular surface temperature change before, during and after routine procedures

Abstract Procedures including teeth clipping (TEE), tail docking (TAI), and ear tagging (TAG) are conducted routinely in commercial pig production units during the first days of life in piglets. However, as these procedures are conducted without anesthetics, there is controversy surrounding these procedures due to the pain/stress they may cause. The assessment of vasomotor activity using non-invasive infrared thermography (IRT) is increasingly being promoted as a tool to detect acute stress. The objective of this study was to assess changes in the ocular (OCU) window of piglets before, during and after each of the aforementioned procedures using IRT. This study used crossbred piglets (n = 116; Duroc Danish x Landrace x Large white) from multiparous sows. All thermographic images of piglets were taken between 0900 h and 1600 h using a high-resolution handheld infrared camera FLIR T650sc (640 x 480 pixels; FLIR Systems, Wilsonville, USA) at a uniform distance of 1 m on the left side of the face. To assess TEE, TAI and TAG procedures separately, a recovery period (12 ± 2.5 min) was allowed between procedures. Due to order differences in which procedures were conducted, the following study groups were created (procedures in brackets indicate the procedures performed prior to the focal procedure): TEE, (TEE+) TAI, (TEE+TAI+) TAG, TAI, (TAI+) TEE, (TAI+TEE+) TAG, TAG, (TAG+) TEE, (TAG+TEE+) TAI. Temperature values were recorded from images using FLIR Tools software 6.0 (FLIR Systems). Data were analyzed using a linear mixed model for repeated measures and multiple comparisons were calculated using a post-hoc Tukey test (GraphPad Prism 10.0.2). Table 1 shows the mean and standard deviation (SD) values for IRT recordings in the OCU window. Comparison of evaluation times showed a significant reduction in OCU temperature from before to after the procedure(s) in (TEE+) TAI (-1.21 °C, P &amp;lt; 0.001), (TAI+TEE+) TAG (-0.65 °C, P &amp;lt; 0.001), TAG (-0.58 °C, P &amp;lt; 0.05) and (TAG+TEE+) TAI (-0.3 °C, P &amp;lt; 0.01) groups. These changes in the OCU window of piglets may be in response to the procedures performed, resulting in a sympathetically mediated acute vasomotor response as cutaneous capillary blood flow shifts due to transient peripheral vasoconstriction. In turn, IRT detects this blood flow change as a reduction in surface temperature. Comparison between procedure groups found that mean OCU temperature during the procedure was greater (P = 0.01) in (TAI+) TEE and (TAG+) TEE than the rest of the groups, though the reason for this is unclear and requires further investigation. This work shows that IRT can be used as a non-invasive tool to detect surface temperature changes of piglets.

Fabrication of a cost-effective metal oxide-based adsorbent from industrial waste slag for efficient CO2 separation under flue gas conditions

Efficient and affordable adsorbents for CO2 capture are essential in implementing carbon capture technology to mitigate the negative impact of greenhouse gas emissions. This study focuses on synthesizing new nanoporous adsorbents from industrial waste slag using a simple and cost-effective coprecipitation method. In this method, raw slag was milled for 48 h and used as a benchmark for comparing two newly synthesized adsorbents. Selectivity and pure gas isotherm experiments were conducted for all adsorbents in the 25–65°C temperature range and under harsh industrial conditions of 65°C and 15 % CO2. This study utilized the response surface methodology (RSM) to optimize the CO2 adsorption parameters. Specifically, the optimized adsorption conditions were determined for the 15/85 % CO2/N2 condition, and the optimal values for pressure and temperature were found to be 5 bar and 45°C, resulting in CO2/N2 selectivity of 5.65. The NH3-slag adsorbent was identified as the superior choice based on its selectivity and maximum adsorption capacity. The maximum adsorption capacity and cyclic efficiency were determined to be 4.15 mmol/g and 98.1 %, respectively, at a temperature, pressure, and composition of 45°C, 5 bar, and 15 % CO2. Isotherm and thermodynamic models were employed to further investigate the adsorption process. The isotherm results indicated that the adsorption of CO2 by adsorbents occurred heterogeneously in patch-wise sites. Meanwhile, the thermodynamic parameters showed that the process was exothermic and spontaneous, with ΔH° falling below 20 (kJ/mol), showing physisorption phenomena.

XP-Endo Finisher behaviour and irrigant temperature in intracanal environment: Clinical measurements.

To evaluate the behaviour of the XP-Endo Finisher and the variation in the intracanal temperature of the irrigant at rest and when activated over time. Differential scanning calorimetry (DSC) determined the transformation temperatures of XP-Endo Finisher instruments. A digital thermocouple was used to measure the temperature of the irrigant inside the pulp chamber. Two measurements were performed for each tooth (n = 12): with the irrigant at rest and during XP-Endo agitation for 60 s to observe the temperature evolution. The data were statistically analysed using a t-test with a confidence level of 95%. DSC results suggested that the XP-Endo Finisher had a mixed R-phase and austenitic structure at room temperature. The temperature values at predetermined time points (0, 10, 40, 70, 120 and 240 s) were measured, and no statistical difference was observed between the values of the resting and activated solutions at any of the selected points (p > .05). For the protocol performed with the XP-Endo file, the mean irrigant temperature observed at instrument insertion inside the root canal was 28.65°C. After 60 s of agitation, the temperature was 34.02°C. The solution temperature stabilized inside the canal only after 211 s at 35.5°C. The mean maximum irrigation solution temperature recorded inside the canal was 35.5°C without agitation and after XP-endo agitation (p > .05). Although the XP-Endo Finisher system does not promote heating of the irrigation solution, file expansion responsible for improved instrument cleaning starts at a temperature below the expected value.

High resolution stable isotope ratios in modern African land snails: Testing inferred environmental conditions

High-resolution sub-annual stable oxygen isotope data were measured in modern land snail shells collected from different climatic zones in Africa to search for patterns in seasonal δ18O cycles associated with specific hydroclimates, keyed to flora/biozones. Thirty-three recently dead shells were collected between 1995 and 2012, and collection localities were divided into five climate types: tropical forest, woodland savannah, bushland savannah, woodland monsoon, and arid/semi-arid. Thirteen genera are represented in the collection. Sampling covered at least one year in the life of the land snails, often multiple years. A comparison of measured data to predicted δ18O values, using local temperature and rain δ18O value, shows that predictions tend to be lower than measured values, suggesting that surface waters or snail body waters have undergone some evaporation. Predictions based on night-time temperatures (average monthly minimum T) are closer to, but still underestimate, measured values compared to day-time (maximum) temperatures in a majority of cases. The largest range in δ18O values for individual shells occurs in the bushland savannah and woodland monsoon biomes. Longer seasonal intervals of dry conditions lead to greater δ18O ranges in shells, although if the dry interval approaches 10 months in the year the amplitude is again reduced. This is in agreement with other oxygen isotope studies of high-resolution land snail shell samples, which show very high δ18O variance in strong monsoon climates.

Effect of Polygonatum cyrtonema Hua polysaccharides on gluten structure, in vitro digestion and shelf-life of fresh wet noodle

This study aimed to investigate the effects of raw Polygonatum cyrtonema Hua polysaccharides (RPCPs) and “zhi” P. cyrtonema Hua polysaccharides (ZPCPs) on the gluten structure, in vitro digestion, and shelf life of fresh wet noodles (FWN). The results demonstrated that incorporating PCPs improved the cooking and sensory qualities of FWN. Moreover, the shelf life of FWN was extended by 6 days with 1.5 % RPCPs (w/w) compared with the control FWN. Furthermore, incorporating 1.5 % ZPCPs led to a 1.2- and 0.2-fold increase in the disulfide bond and α-helix content, respectively, compared with the control FWN. This resulted in enhanced gluten structure, improved springiness and viscidity, and reduced cooking loss by 14.47 %–52.19 %. The scanning electron microscopy analysis revealed that the starch particles were entrapped by PCPs, leading to higher gelatinization temperature and lower setback value of FWN, thereby reducing the starch digestion ratio to 55.50 %. In summary, the findings suggested that FWN containing PCPs can extend shelf life, improve taste, and slow starch digestion staple.

Diverse Strategies to Develop Poly(ethylene glycol)-Polyester Thermogels for Modulating the Release of Antibodies.

In this work, we present basic research on developing thermogel carriers containing high amounts of model antibody immunoglobulin G (IgG) with potential use as injectable molecules. The quantities of IgG loaded into the gel were varied to evaluate the possibility of tuning the dose release. The gel materials were based on blends of thermoresponsive and degradable ABA-type block copolymers composed of poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) or poly(lactide-co-caprolactone)-b-poly(ethylene glycol)-b-(lactide-co-caprolactone) (PLCL-PEG-PLCL). Primarily, the gels with various amounts of IgG were obtained via thermogelation, where the only factor inducing gel formation was the change in temperature. Next, to control the gels' mechanical properties, degradation rate, and the extent of antibody release, we have tested two approaches. The first one involved the synergistic physical and chemical crosslinking of the copolymers. To achieve this, the hydroxyl groups located at the ends of the PLGA-PEG-PLGA chain were modified into acrylate groups. In this case, the thermogelation was accompanied by chemical crosslinking through the Michael addition reaction. Such an approach increased the dynamic mechanical properties of the gels and simultaneously prolonged their decomposition time. An alternative solution was to suspend crosslinked PEG-polyester nanoparticles loaded with IgG in a PLGA-PEG-PLGA gelling copolymer. We observed that loading IgG into thermogels lowered the gelation temperature (TGEL) value and increased the storage modulus of the gels, as compared with gels without IgG. The prepared gel materials were able to release the IgG from 8 up to 80 days, depending on the gel formulation and on the amount of loaded IgG. The results revealed that additional, chemical crosslinking of the thermogels and also suspension of particles in the polymer matrix substantially extended the duration of IgG release. With proper matching of the gel composition, environmental conditions, and the type and amount of active substances, antibody-containing thermogels can serve as effective IgG delivery materials.

Analysis of spectroscopic characteristics of Sm3+ ions doped gallium silicate glasses for orange-red LEDs

In this work, a variety of Sm3+ ions doped gallium silicate glasses have been made using the conventional melt quenching procedure, and characterized by X-ray diffraction, absorption spectrum, fluorescence spectrum, fluorescence decay curves, respectively. The density of the glass increases with the increase of the concentration of Sm3+ ions, and XRD shows that the samples are all amorphous glasses. Absorption spectra were used to determine the J-O intensity parameters (Ωλ, λ = 2, 4, 6), as well as the radiation transition probability(A), fluorescence branching ratio(βr), and radiation lifetime(τr) of Sm3+ ions at the 4G5/2 energy level. Under 403 nm excitation, the emission spectra show obvious emission peaks at 602 nm and 649 nm, corresponding to 4G5/2 → 6H7/2 and 4G5/2 → 6H9/2 transitions respectively. The B3 glass sample has the largest emission cross section(σem) at the 4G5/2 → 6H7/2 transition, with σem = 11.40 × 10−22 cm2. The color coordinates, color purity and color temperature values of all samples were calculated. The color purity of all samples varied in the range of 96.20%–99.14 %, with the relevant samples separating in the orange-red light region. The experimental results indicate that the glass samples have a potential application prospect in the field of orange-red LEDs.

Integrating hydrogen into a hybrid system to meet a laboratory's electricity demand

Providing quality electricity to improve the living conditions of rural and urban populations in Africa, particularly in Cameroon, represents a challenging but achievable task. Indeed, Cameroon has the second largest hydrographic network in Central Africa, and thanks to this network, over 90% of electricity comes from aging hydroelectric dams that cause permanent power outages. The desire to take advantage of other benefits that nature has given this country has directed this work towards renewable energies. Thanks to the HOMER Pro software, a renewable energy hybrid system with hydrogen gas serving as storage and energy vector was adopted. Photovoltaic panels and wind turbines are proposed as primary energy sources for the permanent, low-cost supply of the IRAD laboratory at the University of Maroua. The software proposes three systems, one with the wind turbine as the only primary source, and considered as the most optimal. It has an energy cost equal to $0.0633, an NPC of $20330, and an initial capital of $8500. The other two systems are hybrids with a renewable fraction equal to 100%, and a load distribution strategy that is the charge cycle (CC) like the first system. The first less expensive hybrid system has an energy cost and an NPC respectively of $0.0778 and $24986. As for the second hybrid system, it has an NPC and an energy cost respectively of $26195 and $0.0778. Hydrogen fully plays its role as an energy vector and storage in all three systems. A sensitivity analysis was conducted in this work to ensure that the system proposed for the laboratory can also be adapted in the 9 other regions of the country. It appears that the values of wind resources, solar radiation, and temperature have a significant impact on the energy cost. The cities of Yaoundé and Ebolowa, displaying respective wind speeds of 2.07 m/s and 1.76 m/s, are recognized for having the lowest wind speeds in the country, which hinders the overall energy production and profitability of the system. The hybrid system suggested for these cities proves to be expensive, with energy costs exceeding the standard electricity price set by the energy distribution and marketing organization in the country.

Study on the Adsorption Law of n-Pentane in Silica Slit Nanopores.

As the main components of shale, inorganic minerals are important carriers for oil and gas adsorption, whose pore structures and surface properties have significant effects on the fluid adsorption capacity. In this study, slit nanopores (SNPs) were constructed by silica. To investigate the microscopic adsorption law of n-pentane in silica, the grand canonical Monte Carlo (GCMC) method was used to simulate the adsorption behaviors of n-pentane in silica nanoparticles. The effects of different surface wettability, pore size, temperature, and pressure values on the adsorption behavior of pentane were discussed, revealing the micro adsorption mechanism of pentane in silica with different pore sizes and wettability and evaluating the degree of oil and gas utilization. The research results indicate that the adsorption capacity of pentane is greatly affected by the temperature under low-pressure conditions. With the increase of the pore size, the adsorption capacity of pentane increases linearly, and the number of adsorbed pentane molecules gradually decreases. The availability of oil and gas increases, and the oil and gas are more easily extracted. As the surface hydrophobicity of minerals increases, the van der Waals force between minerals and pentane also increases, leading to an increase in the number of adsorbed states of pentane. The stronger the hydrophilicity of the wall, the fewer the pentane molecules adsorbed on the surface, which would improve the efficiency of oil and gas extraction. This study provides potential for the development of novel surfactants based on adsorption selectivity.

The SRG/eROSITA all-sky survey. X-ray emission from the warm-hot phase gas in long cosmic filaments

The properties of the warm-hot intergalactic medium (WHIM) in cosmic filaments are among the least quantified units in modern astrophysics. The Spectrum Roentgen Gamma/eROSITA All Sky Survey ((SRG/eRASS) provides a unique opportunity to study the X-ray emission of the WHIM. We applied both imaging and spectroscopic stacking techniques to the data of the first four eRASS scans to inspect the X-ray emissions from 7817 cosmic filaments identified from Sloan Digital Sky Survey (SDSS) optical galaxy samples. We obtained a $9 significant detection of the total X-ray signal from filaments in the 0.3--1.2 keV band. Here, we introduce a novel method to estimate the contamination fraction from unmasked X-ray halos, active galactic nuclei, and X-ray binaries associated with filament galaxies. We found an approximately 40&lt;!PCT!&gt; contamination fraction for these unmasked sources, suggesting that the remaining 60&lt;!PCT!&gt; of the signal could be coming from the WHIM and a $5.4 detection significance of the WHIM. Moreover, we modeled the temperature and baryon density contrast of the detected WHIM by fitting the stacked spectrum and surface brightness profile. The best-fit temperature $ K obtained by using a single temperature model, is marginally higher than in the simulation results. This could be due to the fitting of a single temperature model on a multi-temperature spectrum. Assuming a 0.2 solar abundance, the best-fit baryon density contrast $ b is in general agreement with the X-ray emitting phases in the IllustrisTNG simulation. This result suggests that the broadband X-ray emission traces the high end of the temperature and density values that characterize the entire WHIM population.

Colour tunability of Dy3+ & Sm3+ activated yttrium aluminium gallium nanocrystals for display applications

A set of powder samples of Y3AlGa4O12 doped with Dy3+ and Sm3+ with different concentration of Sm3+ ion were prepared via sol-gel synthesis. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive (EDS), Fourier transform infrared (FTIR) and photoluminescence spectral studies were carried out. All the diffraction peaks matched the cubic lattice Y3AlGa4O12, as given by the XRD. The SEM images revealed aggregated spherical particles ranging from 50 to 130 nm. The EDS analysis confirmed the presence of the initial chemicals in the synthesized samples. FTIR spectrum was used to examine the vibrational modes in the sample. Under a 366 nm excitation wavelength, the emission spectrum showed the peaks at 492 nm (blue), 580 nm (yellow), 673 nm (red), and 760 nm (near-infrared) corresponding to the characteristic transitions 4F9/2 → 6H15/2,13/2,11/2,9/2 of the Dy3+ ion, respectively. In comparison, the peaks at 568 nm, 614 nm, 664 nm, and 711 nm corresponded to the characteristic transitions 4G5/2 → 6H5/2,7/2,9/2,11/2 of the Sm3+ ion. Under near ultraviolet light excitation, the superposition of these blue, yellow and red colours produced excellent white light emission. The intensities of these transitions varied with the concentration of Sm3+ ion and the excitation wavelength. The emission spectrum of Dy3+ overlapped with the excitation spectrum of Sm3+, indicated possible energy transfer from Dy3+ to Sm3+. According to Inokuti-Hirayama's theory of energy transfer, the mechanism of energy transfer was understood to be quadrupole-quadrupole interaction. The CIE chromaticity co-ordinates and correlated colour temperature values showed that these samples were suitable for light-emitting diode applications.