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In order to study the effect of temperature effect on CO2 injection and gas extraction in deep coal seams, a fluid-solid-thermal coupling model for CO2-injection enhanced coal seam extraction was established based on the basic theory of coal deformation characteristics and gas seepage characteristics, which also considered non-isothermal adsorption, binary gas competitive adsorption, gas seepage and diffusion, heat transfer and heat convection. The influence of temperature effect on coal reservoir parameters and gas production evolution law is investigated. The results show that the shrinkage of coal matrix caused by coal bed temperature decrease promotes CH4 desorption, and the fluid-solid coupling model ignoring temperature effect will underestimate gas production. When the initial permeability is 3.95×10−17 m2 and the CO2 injection pressure is 8 MPa, for the deep coal body buried 1 400 m in the No. 3 coal seam in Hancheng Mining area, compared with the fluid-solid-thermal coupling model considering the temperature effect (319.5 K), the gas extraction time of 3 650 days is higher than that of the fluid-solid coupling model. The average gas pressure of coal seam decreased by 0.69%, the permeability of A point increased by 11.02%, the gas production rate increased by 13.51%, and the cumulative gas production increased by 13.76%.

In order to explore the influence of thermal effect and strain on gas drainage, a fluid solid thermal coupling model considering coal deformation, gas adsorption and thermal effect was established to simulate the influence of thermal effect and strain on gas drainage. The results show that the gas production rate is 11.48% higher and the gas production rate is 11.45% higher when the thermal effect is considered than when the thermal effect is not considered. The stronger the thermal effect, the greater the permeability, and the higher the gas production. This shows that the influence of thermal effect on gas drainage cannot be ignored; the influence of different strains on gas extraction is different, adsorption strain > temperature strain > pressure strain.

The technology of CO2-enhanced coalbed methane (CO2-ECBM) can reduce greenhouse gas emissions, and has the function of clean energy production and environmental protection. In order to study the drainage and production laws of CH4 production by CO2 injection in water-bearing coal seams under gas-water two-phase flow conditions, as well as the effects of different initial water saturation and CO2 injection conditions on CH4 production, CO2 storage, and reservoir permeability. A coupled fluid-solid-thermal model for competitive adsorption, temperature changes, coal deformation, and water transport was constructed. The high accuracy of the model was demonstrated by comparing with the field data, existing experiments and numerical solutions of existing model, and the advantages of the model were specified. CO2-ECBM numerical simulation were subsequently carried out using COMSOL. The results shown that, CO2 injection can enhance the rate and amount of CH4 production, which indicated the feasibility of CO2 injection to increase production. With the continuous CO2 injection, the CH4 concentration in the reservoir decreased, the CO2 concentration increased, the temperature near the gas injection well increased, the temperature near the production well decreased and the temperature from the gas injection well to the production well slowly decreased. Water phase relative permeability gradually decreased and gas phase relative permeability gradually increased during gas injection and extraction period. Due to the combined effect of effective stress and matrix shrinkage/expansion, the reservoir permeability exhibited a trend of “decrease-increase-decrease”. The higher the initial water saturation of the coal seam, the lower the CH4 production and the lower the permeability decrease. The maximum decrease in cumulative CH4 production was 15.19%. Ignoring the impact of water in coal seams can overestimate CH4 production, and the impact of coal seam water should be considered in numerical simulation. The higher the CO2 injection temperature and pressure, the greater the CH4 production and the greater the permeability decrease. The cumulative CH4 production increased by 13.27% and 39.77%, and permeability decreased by 20.4% and 46.14%, respectively. Increasing the CO2 injection temperature and pressure was conducive to increase CH4 production.

Let $ k, l, m_1 $ and $ m_2 $ be positive integers and let both $ p $ and $ q $ be odd primes such that $ p^k = 2^{m_1}-a^{m_2} $ and $ q^l = 2^{m_1}+a^{m_2} $ where $ a $ is a positive integer with $ a\equiv {\pm 3}\pmod 8 $. In this paper, using only the elementary methods of factorization, congruence methods and the quadratic reciprocity law, we show that Je$ \acute{s} $manowicz' a conjecture holds for the following set of primitive Pythagorean numbers: $ \frac{q^{2l}-p^{2k}}{2}, p^kq^l, \frac{q^{2l}+p^{2k}}{2}. $ We also prove that Je$ \acute{s} $manowicz' conjecture holds for non-primitive Pythagorean numbers: $ n\frac{q^{2l}-p^{2k}}{2}, np^kq^l, n\frac{q^{2l}+p^{2k}}{2}, $ for any positive integer $ n $ if for $ a = a_1a_2 $ with $ a_1\equiv 1 \pmod 8 $ not a square and $ \gcd(a_1, a_2) = 1 $, then there exists a prime divisor $ P $ of $ a_2 $ such that $ \left(\frac{a_1}{P}\right) = -1 $ and $ 2|m_1, a\equiv 5 \pmod 8 $ or $ 2\not|m_2, a\equiv 3\pmod 8 $.

The knowledge of the biological aspects and feeding activity of fish is required to manage the lack of data on fisheries. In this study, a total of 200 Plotosus canius were caught and examined to obtain information on their biological aspects, length-weight relationship, and feeding activity. The fish were captured using a gill net and traditional fishing trap called Bubu. Subsequently, all samples were examined for total body weight, total length, condition factor, gonad maturity, and feeding activity. The results showed that the specimens captured were 156 males and 44 females weighing between 95-280 gr and 117-214 gr with the length of 26-39 cm and 28-36.3 cm, respectively. The length-weight relationship showed a negative allometric growth pattern. The mean condition factors of males and females were 1.1048 and 1.0102, respectively. At the same time, the maturity level of gonads was at I and II. Moreover, it was discovered that most organisms in the digestive tract were shrimp, worms, small fish, and crabs, while the highest index of preponderance was in shrimp with 42%. In conclusion, this study showed the new information about length-weight, biological condition, and feeding habits of Plotosus canius, which can be inventoried to strengthen data on sustainable fisheries management.

The aim of this study was to provide a sensitive model animal for studying hyperuricemia. Male uricase-deficient rats, named Kunming-DY rats, were raised for 130 days, or orally administered with purines and other chemicals. Serum uric acid (SUA) in the animals was assayed, and the UA level in their organs and their 24-h excretion was determined. Genes in the jejunum, ileum, kidney and liver related to UA synthesis and transportation were detected by quantitative RNA sequencing. Uricase-deficient rats have a high level of SUA and are sensitive to xanthine, adenosine, inosine, allopurinol, and alcohol. Besides, the high level of SUA in male uricase-deficient rats was stable, much higher than that in wild-type rats but similar to that in men. The distribution pattern of UA in uricase-deficient rats’ organs was different from that in wild-type rats. The kidney, liver, and small intestine were the top three organs where UA distributed, but the UA in the small intestine, colon, lung, thymus, and brain was less affected by uricase deficiency, indicating that these organs are constitutive distribution organs in UA. The 24-h UA excreted by a uricase-deficient rat was about five times higher than that excreted by a wild-type rat. However, the 24-h UA excreted through feces was not significantly changed. Both the urine volume and UA in uricase-deficient rats significantly increased, and more than 90% of UA was excreted via urine. The expression of xanthine dehydrogenase was not upregulated. Some genes of transporter associated with uric acid excretion in the kidney were significantly regulated, though not sufficient to explain the increase in SUA. In conclusion, male uricase-deficient rats’ UA metabolism is similar to that of men. The elevation of SUA in uricase-deficient rats is caused by uricase deficiency, and uricase-deficient rats are a sensitive model for studying hyperuricemia.

Abstract As an effective carbon utilization technology, the injection of N2/CO2 mixtures into coal seams has significant potential for improving coalbed methane recovery. Considering the technical barrier that injection of pure CO2 decreases the well injectivity index and pure N2 injection leads to the rapid methane recovery, a method of injecting N2‐enriched gas mixtures with a constant component is proposed. In this study, a thermo‐hydro‐mechanical (THM) coupling numerical model for enhanced coalbed methane (CBM) recovery by injecting N2/CO2 mixtures is established. This model includes complex interactions of coal deformation, competitive adsorption, ternary gas seepage, and heat transfer. The THM coupling model is first validated, and then applied to investigate the evolution of mixed gas concentrations, reservoir permeability, reservoir temperature, CH4 production, and N2/CO2 storage during N2/CO2 enhanced CBM recovery. The results show that the displacement radius and concentration of the mixed gas in the coal seam increased with gas injection pressure increase. The concentration of CH4 gradually decreased with time, and the early decline is faster than the later stage. The sweep of the N2 flow accelerates CH4 desorption and migration, promoting a reduction in reservoir temperature near the production well. Reservoir permeability evolution results from the combined effects of ternary gases (CH4, CO2, N2) competitive adsorption, gas pressure, and geostress on the coal seam within the THM fields. At the methane natural depletion stage (within 250 days), the permeability of coal reservoir first decreases and then increases. With the arrival of the N2/CO2 mixture, the permeability decreases dramatically. From the perspective of cumulative CH4 production, the optimal composition is dominated by the synergistic effect of maximizing breakthrough time and minimizing coal matrix swelling. For 30% CO2‐70% N2, the CH4 recovery ratio reached 71.76%, representing an increase of 16.67% compared to natural depletion.

Abstract The similarity in the structure and function between leaf veins and multibranch wells provided the inspiration for a novel design of multibranch coalbed methane (CBM) well. The leaf vein structure of leaves was analyzed by leaf specimen scanning and microstructure measurements. Fluorescence labeling experiments were used to study the influence of leaf vein structure on moisture transport, and the geometric characteristics were obtained. A CBM extraction physical simulation experiment was carried out in a custom‐made experimental system. The temporal and spatial evolution of seepage‐temperature fields in reservoir during CBM recovery were studied, and the influence of leaf vein geometric characteristics and how they affected was analyzed. The results indicated that in experimental gas extraction, asymmetrically distributed branch wells improved the CBM recovery 4.02% higher than symmetric structure after 1000 seconds. The reduction in branch well angle leads to the decrease in gas pressure relief. If the branch well angle is reduced by 20°, it reduced by 11.34% after 4000 seconds. When the branch well length increased by 50%, it increased by 28.37%. Coalbed methane recovery effect can be improved by 6.81%, when the distance between branch wells increased by 50%. In the early extraction stage, the reduction in methane pressure and reservoir temperature was positively correlated with the initial methane pressure, but they were less affected in the later stage.

Uricase-deficient rats could be one of the optimal model animals to study hyperuricemia. The present study aimed to find the biological differences between uricase-deficient (Kunming-DY rats) and wild-type male rats. Uricase-deficient rats and wild-type rats were commonly bred. Their body weight, water and food consumption, 24-h urine and feces, uric acid in serum and organs, and serum indexes were recorded or assayed. Organs, including the heart, liver, spleen, lung, kidney, thymus, stomach, duodenum, and ileum, were examined using a routine hematoxylin-eosin staining assay. We found that the growth of male uricase-deficient rats was retarded. These rats excreted more urine than the wild-type rats. Their organ indexes (organ weight body weight ratio), of the heart, liver, kidney, and thymus significantly increased, while those of the stomach and small intestine significantly decreased. The uricase-deficient rats had a significantly higher level of serum uric acid and excreted more uric acid via urine at a higher concentration. Except for the liver, uric acid increased in organs and intestinal juice of uricase-deficient rats. Histological examination of the uricase-deficient rats showed mild injuries to the heart, liver, spleen, lung, kidney, thymus, stomach, duodenum, and ileum. Our results suggest that uricase-deficient rats have a different biological pattern from the wild-type rats. Uricase deficiency causes growth retardation of young male rats and the subsequent increase in serum uric acid results in mild organs injuries, especially in the kidney and liver.

Urate oxidase (uricase, Uox) is a big obstacle for scientists to establish stable animal models for studying hyperuricemia and associated disorders. Due to the low survival rate of uricase-deficient mice, we generated a Uox-knockout model animal from Sprague Dawley (SD) rats using the CRISPR/Cas9 technique by deleting exons 2 to 4 of the Uox gene. The uricase-deficient rats were named “Kunming-DY rats”, and were apparently healthy with more than a 95% survival up to one year. The male rats’ serum uric acid (SUA) increased to 48.3 ± 19.1 µg/ml, significantly higher than those of wild-type rats. Some indexes of the blood fat like total triglyceride, low density lipoprotein, and renal function indexes including blood urea nitrogen and serum creatinine were significantly different from those of wild-type rats, however, all the indexes were close to or in normal ranges. Histological renal changes including mild glomerular/tubular lesions were observed in these uricase-deficient rats. Thus, “Kunming-DY rats” with stable uricase-deficiency were successfully established and are an alternative model animal to study hyperuricemia and associated diseases mimicking human conditions.