Quadratic Regression Equation Research Articles

Research and analysis of the influence of recipe and technological factors on the strength of expanded clay concrete on quartz sand

The aim of the work is to study the strength and deformation properties of expanded clay concrete on cement-ash binder and to prove the technical possibility and economic feasibility of its study in structural elements of civil buildings. The five-factor plan B5 was implemented. In the matrix, each of the technological factors changed at three levels (-1; 0; +1), which made it possible to obtain quadratic mathematical models of output parameters - the bulk mass of concrete, cubic and prismatic strength of the expanded clay concrete at the age of 1 (a.s), 28, 115, 180 and 360 days, when the expanded clay concrete mixture is mobile (the constant draught of the cone is DC= 2...6 сm). Processing of experimental results to identify regularities of influence of studied factors - consumption: cement (x1); lime (х2); fly ash (х3); expanded clay gravel (х4); quartz sand (x5) on water consumption of ceramic and concrete mixtures – B, volume of inter-grain voids Vn, the density of the ceramic concrete mixture – ρo and the density of the expanded clay concrete ρ allowed to obtain with 95% reliability quadratic regression equations, taking into account only significant regression coefficients. Based on the results of experimental studies with 95% reliability quadratic regression equations of cubic and prismatic strength in the age of 1 (a.s), 28, 180* and 360* days are obtained, expanded clay concrete on CLF-binder and quartz sand with only significant regression factors. The paper examines and analyzes the influence of recipe and technological factors on the strength of expanded clay concrete on quartz sand. The invention makes it possible to use the dependence of a cubic and prism strength expanded clay concrete on quartz sand using a large component binder with a further prospect of saving cement and fillers.

Strength and workability of one-part sodium carbonate activated mortar incorporated with silicomanganese slag

This research utilized sodium carbonate (Na2CO3) as an alkaline activator to produce one-part alkali-activated mortar (AAM) with silicomanganese (SiMn) slag as the aluminosilicate precursor. In the experiment, the effect of Na2CO3 dosage (4 %, 6 %, 8 %, 10 %, 12 %) and binder replacement with ordinary Portland cement (OPC) (10 %, 30 %, 50 %) on the compressive strength and workability of AAM was investigated. To improve the workability, several types of superplasticizer (SP), including MasterGlenium ACE 389 (MG) and sodium naphthalene sulfonate formaldehyde (SNSF), and retarder, including REAL SET 231 (RS231) and vinegar (acetic acid), were incorporated. The relationship between strength and workability of one-part AAM was also established. The results showed that increasing the Na2CO3 content from 4 % to 10 % improved the strength by about 2 times but reduced workability by 7.8 % due to the increased alkalinity and OH− concentration. The incorporation of up to 50 % OPC further increased the strength by 3.2–5.3 times due to the synergetic effect of alkali activation of SiMn slag and cement hydration. In addition, SNSF-type SP outperformed MG-type SP in terms of workability and compressive strength. Both the RS231 retarder and acetic acid enhanced the workability by 8%–48 % and strength by 10.5 %–28.3 %. A quadratic regression equation with R2 values of 0.58–0.81 was developed to correlate the strength and workability of one-part AAM.

Orthogonal experimental study of ultrasound-assisted fused deposition molding

To improve the quality of fused deposition molding (FDM), we introduced ultrasonic vibration into the molding process to enhance the strength of the tensile samples. We used the response surface method to optimize the FDM molding process. We carried out orthogonal experiments to investigate the effects of ultrasonic power and process parameters (extrusion temperature, hotbed temperature, and delamination thickness) on the mechanical properties of fused deposition acrylonitrile butadiene styrene products. We obtained the quadratic regression equations and response surfaces of the data through analysis of variance and significance analysis by software. Last, we received the optimum combination of process parameters for tensile strength as extrusion temperature 233.85 °C, hotbed temperature 93.38 °C, delamination thickness 0.1 mm, and ultrasonic power 43.09 W.

Solar photothermal utilization of coupled latent heat storage: A numerical and optimization study

The combination of Organic Rankine Cycle (ORC) and Latent Heat Thermal Energy Storage (LHTES) is a novel approach for effectively utilizing solar energy. However, the influence of solar energy fluctuations on the heat transfer process of LHTES systems is not yet clear. In this study, a sinusoidal heat source is applied to a rotating triple-tube LHTES system, and numerical analysis and model verification are conducted. The parameters of the sinusoidal heat source are optimized using the response surface method. The effects of heat source amplitude, half period, and rotation speed on the heat release time and heat release rate of LHTES are investigated, and corresponding quadratic regression equations are fitted. The optimized structure (rotation speed = 0.5 rpm, amplitude = 7.5 K, half-cycle = 100) obtained through the response surface method reduced the solidification time by 12.45% compared to the initial structure (rotation speed = 0.3 rpm, amplitude = 7.5 K, half-cycle = 100). The average temperature response and heat release rate increased by 28.34% and 16.25%, respectively. The sensible heat and total heat release within one solidification cycle increased by 12.17% and 1.87%, respectively. This study lays the foundation for the optimization design of LHTES systems and the integrated application of Organic Rankine Cycle.

Response surface optimization for deep eutectic solvents extraction of bamboo shoots proteins

To enhance the protein extraction rate of bamboo shoots, the Response Surface Methodology was utilized to optimize the protein extraction process of Chimonobambusa purpurea Hsueh f. & T.P.Yi (syn. Chimonobambusa neopurpurea T.P.Yi) bamboo shoots. Choline chloride and proline were utilized as hydrogen bond acceptors in a total of eight deep eutectic solvents, whereas glucose, sucrose, glycerol, ethylene glycol, acetylpropionic acid, malic acid, and lactic acid were used as hydrogen bond donors. This work examined the protein extraction from bamboo shoots using deep eutectic solvents. Single-factor experiments were conducted to determine the optimal composition of the deep eutectic solvents, along with the ideal gradients of material-liquid ratio gradients, water content, extraction time, and water bath temperature. The impact and interplay of various variables on the protein extraction rate of bamboo shoots were examined using the Box-Behnken Design and Response Surface Methodology. Both the water bath temperature and the extraction time significantly influenced the protein extraction rate of bamboo shoots. Notably, the interaction between extraction time and water bath temperature had the most substantial effect on the protein extraction rate of bamboo shoots. The quadratic response surface regression equation for the protein extraction rate of bamboo shoots relative to the actual values of each factor was obtained as follows: Protein extraction rate = −193.3275 + 3.8395 A - 18.7075 B + 6.3285 C + 0.2125 AB - 0.0089 AC + 0.024 BC - 0.02885 A2 + 0.685 B2 - 0.06455 C2. Finally, this work predicted optimum extraction parameters for bamboo shoots with choline chloride-sucrose (molar ratio 1:2), a material-liquid ratio of 1:50, a water content of 74 %, an extraction time of 4 h, and a water bath temperature of 44 ℃. Under the optimal conditions, the protein extraction yield was 59.39±0.45 %, which aligned with the predicted value from the response surface fitting equation. This indicated that the optimised regression equation may have practical significance. Compared with conventional extraction using a sodium hydroxide (NaOH) solution, deep eutectic solvents extraction of bamboo shoots is more environmentally friendly, non-toxic and harmless. It provides a theoretical and experimental reference for industrial extraction and offers a reference for deep eutectic solvent development in bamboo shoot resource utilization.Key message:To enhance the protein extraction rate of bamboo shoots, the Response Surface Methodology was utilized to optimize the protein extraction process of bamboo shoots.

Multi-Objective Optimization of Process Parameters in Laser DED Ni-Based Powder on Steel Rail Using Response Surface Design

With the rise of global industrialization, the requirements for the operating speed and carrying capacity of high-speed trains are increasingly higher. Because the wear and tear of rails gradually increases during the running of high-speed trains, strengthening or repairing rail surfaces is of paramount significance. Laser-directed energy deposition (DED) exhibits significant advantages in improving surface hardness, corrosion resistance, and abrasion resistance. Because of the multiple interacting optimization objectives, the development of a multi-objective optimization method for process parameters is significant for improving DED deposition quality. Response surface design employs multivariate quadratic regression equations to fit the functional relationship between the factors and the responses, which can be employed to find the optimal process parameters and solve multivariate problems. This study develops a multi-objective optimization model with response surface design and 2D process mappings to visually analyze the effects of scanning speed, laser power, and powder feed rate on aspect ratio, dilution rate, and microhardness. The optimal combination of process parameters for Ni-based alloys on U71Mn rail is a laser power of 431 W, a scanning speed of 5.34 mm/s, and a powder feed rate of 1.03 r/min. In addition, a multi-physics field finite element model is developed to analyze the evolution mechanism of the microstructure from the bottom to the top of the single track. This study can provide theoretical and technical support for the surface strengthening or repair of U71Mn rail.

Optimizing Preparation of Fish Scale Collagen Peptide/Sacha Inchi (Plukenetia volubilis L.) Seed Oil Nanoemulsion

AbstractThis study presents results of extracting hydrolyzed collagen peptide from fresh‐water fish scale and using it to prepare a nanoemulsion based on Sacha inchi (Plukenetia volubilis L.) seed oil and collagen peptide. The sacha inchi seed oil is extracted from the seeds of Sacha Inchi (abbreviated as sachi) plant and contains approximate 45 % triple omega 3–6‐9 (ω‐3, ω‐6, ω‐9) content. Pseudo‐ternary phase diagrams of three components: aqueous collagen solution, sachi seed oil, and surfactant/co‐surfactant (Smix) have been constructed. The parameters including the composition of Smix, sachi seed oil, and aqueous collagen solution have been selected to optimize the technology factors for the emulsion process. A quadratic regression equation was chosen, and experimental planning following the Box‐Behnken model using response surface methodology was used to optimize the preparation conditions for the nanoemulsion. The average droplet size of the emulsion systems is the object function for optimization. The Smix is a mixture of surfactant (Tween80) and propylene glycol (PG) with different ratios of Tween80/PG of 1/1, 2/1, 3/1, and 4/1, corresponding to the formation of four emulsion systems, code 1, 2, 3, 4, respectively. The optimal parameters for each emulsion system are different, however, the aqueous collagen solution contains a higher proportion in emulsions. Under the optimal conditions, the predicted values of the objective function of emulsions code 1–code 4 ranged from 95.62 to 185.14 nm, increasing together with the Tween80 ratio in Smix. The experiment values of the objective function of emulsions code 1–code 4 prepared under the optimal conditions are 104.22, 133.70, 159.27, and 207.87 nm, respectively. These values are close to the predicted values, suggesting that the suitability of the experiment and theory. Additionally, the stability of the nanoemulsion prepared under the optimal conditions is also evaluated. A stable nanoemulsion is potentially for loading nutraceuticals and vitamins for applications in personal health care and medicinal fields.

Simultaneous effect of pH, deposition time, deposition potential, and step potential on the stripping peak current of lead and cadmium by response surface methodology

In this paper, a simple voltammetric method has been reported for the lead, and cadmium determination using platinum nanoflowers modified glassy carbon electrode (PtNFs/GCE). The effects of pH, deposition time, deposition potential, step potential were investigated on the stripping peak current of lead, and cadmium based on response surface methodology (RSM). The results of RSM analysis and analysis of variance (ANOVA) have shown that the experimental data could be well described by quadratic regression equations with determination coefficients (R2) of 0.935, and 0.972 for the stripping peak current of lead, and cadmium, respectively. Results of the statistical analysis showed that the fit of the model was good in all cases. The maximum stripping peak current of the lead, and cadmium of 5.54µA, and 2.81µA, respectively were obtained at the optimum levels of process variables (pH (4.72), deposition potential (-1.14V), deposition time (120s), step potential (7mV)). Testing the model to analyze lead, and cadmium on the PtNFs/GC electrode using differential pulse anodic stripping voltammetry (DPASV) and obtained with the stripping peak current of the lead, and cadmium of 5.43µA, and 2.75 µA, respectively.

Efficient extraction of oleoresin from Ferula gummosa roots by natural deep eutectic solvent and its structure and chemical characterizations

Deep eutectic solvents in the extraction of plant metabolites have found many advantages, such as low toxicity, biodegradability, low cost and ease of preparation over the conventional methods. This work aims to compare natural deep eutectic solvents in extraction and optimization of oleoresin from Ferula gummosa and determining its chemical and structure properties. Box–Behnken design was applied to optimize the extraction of oleoresin from Ferula gummosa using eutectic solvents. The variables of extraction were extraction time, temperature, and ratio of eutectic solvents. Six mixtures of eutectic solvents including choline chloride/urea, acetic acid, lactic acid, formic acid, formamide and glycerol at ratios of 2:1 and 3:1 were evaluated. The highest yields were obtained for choline chloride/formic acid, choline chloride/formamide. The quadratic regression equation was set up as a predictive model with an R2 value of 0.85. The optimum condition was 6 h, 40 °C, and ratio 12.5% (w/v). No significant difference was found between the predicted and experimental yield. The main components of the oleoresin were β-pinene (40.27%), cylcofenchen (11.93%) and α-pinene (7.53%) as characterized by gas chromatography-mass spectrometry. The chemical structure study by spectroscopy showed that no solvents remained in the oleoresin. Therefore, F. gummosa oleoresin can be explored as a novel promising natural pharmaceutical ingredient extracted with eutectic solvents.

The new approach to calculation of physiological cost of activity: antinociception and normalization of the respiratory pattern of heart rate variability

Purpose of this work is to propose an approach to the assessment of allostatic load based on the antinociceptive effect, which appears, obviously, due to changes in the activity of the endogenous opioid system (EOS); to compare the estimates obtained by measuring the pain threshold and calculating the index of respiratory effects on heart rate variability (HRV). The method of measuring the pain threshold is based on fixing the latent time of the thermonociceptive reaction (LTTR). The respiratory effect is measured by graphically determining the minimum normalized power of the fast HRV component in the range of 0.16...0.67 Hz, corresponding to the frequency of the respiratory pattern. Results. Based on small-volume experimental data (4 athletes and 4 episodes of physical activity), a quadratic two-factor regression equation was calculated for LTTR, respiratory effects factor and stress. A high correlation was demonstrated between the respiratory effect on HRV and the LTTR for one studied athlete. Conclusion. Using the example of sports, it is shown that it is possible to track the physiological cost of activities through LTTR. The inconveniences and subjectivity of the LTTR measurement procedure can be circumvented by replacing it with a normalized numerical index that considers the effect of breathing on HRV and the stress index. The proposed approach demonstrates the presence of reference values in the studied group, but requires further specially planned clinical studies.

Swarm intelligence algorithms for optimising sliding wear of nanocomposites

This paper presents simulation results obtained by a set of modern algorithms adhering to swarm intelligence for minimising wear rate in the case of A356/Al2O3 nanocomposites produced using a compocasting process. Grey wolf optimisation (GWO) algorithm, moth-flame optimisation (MFO) algorithm, dragonfly algorithm (DA) and whale optimisation algorithm (WOA) were the algorithms under examination. A full quadratic regression equation that predicts wear rate, as the optimisation objective by considering reinforcement content, sliding speed, normal load and reinforcement size as the independent process parameters, was utilised as the objective function. Simulation results obtained by the selected algorithms were quite promising in terms of fast convergence and global optimum result arrival, thus prompting to further investigation of applying swarm intelligence to general problem-solving aspects related to tribology.

Unlocking the potential of Garcinia atroviridis fruit polysaccharides: A synergistic approach for obesity and hypertension management

The potential of Garcinia atroviridis fruit polysaccharides (GAP) in inhibiting lipase and angiotensin converting enzyme was investigated. The GAP was initially optimized using microwave-deep eutectic solvents (DES) assisted extraction. The obtained quadratic regression equation served as a predicted model with an R2 value of 0.9385. The experimental maximum yield of the sample (24.33%) closely matched the predicted yield (24.88%), demonstrating the accuracy of the model. The GAP showed a high molecular weight (28.15 × 103 ± 3.17 kDa), viscosity (3.171 ± 1.23 Pa s) as well as high branching size (6.39 ± 0.030) that may have a greater ability to form complex structures that can inhibit targeted enzyme activities. These large structures can physically block the access of enzymes to their substrate, thus reducing the rate of activities. These properties influence the biological activities of extracted GAP that was measured in vitro and showed the inhibition of pancreatic lipase (79.41%) and angiotensin converting enzyme (ACE) – inhibitory activity (81.23%) which shows potential as a viable source for the development of ACE-inhibitory and anti-obesity agents with promising effectiveness. Hence, the GAP can be an alternative source as a therapeutic treatment for hypertension and obesity.

Performance optimization design of trapped vortex combustion chamber with a sand dune blunt body

In an effort to enhance the performance of the trapped vortex combustion chamber, this paper improved the trapped vortex combustion chamber and proposed a sand dune trapped vortex combustion chamber. Firstly, the effects of different inlet velocities and equivalence ratios on the performance of the two combustion chambers were analyzed. The results showed that under the same operating conditions, the performance of the sand dune trapped vortex combustion chamber was better than that of the trapped vortex combustion chamber. Then, a central composite design (CCD) response surface experimental method was adopted to optimize the structure of the sand dune trapped vortex combustion chamber in detail. The windward angle (α), leeward angle (θ), and rear blunt body height (h) were used as influencing factors. The combustion efficiency (η), pressure loss (δ*), and NOx emissions were used as response variables. Quadratic polynomial regression equations for η, δ*, and NOx emissions were established respectively. Subsequent to this, the expected value function method was employed for multi-objective optimization of the three regression equations. After optimization, compared with the original trapped vortex combustion chamber, the combustion efficiency of the sand dune trapped vortex combustion chamber increased from 87.56 % to 95.41 %, NOx emissions decreased from 747.94 ppm to 386.35 ppm, the outlet temperature distribution factor (OTDF) decreased from 0.21 to 0.07, and field synergy β diminished from 83.11 to 76.60. Although the pressure loss increased from 2.30 % to 3.50 %, this is within an acceptable range.

Investigation of computer numerical control wood milling parameters for occupationally safer by the minimization of produced wood dust

ABSTRACT Computer numerical control (CNC) wood machining produces wood dust, harming the operator's health. In this research, the effective parameters of the amount of produced wood dust (PM) in CNC milling are investigated. The design of the experiment was done based on the response surface method (RSM) and subsequently, 27 experimental tests were performed. The results of the analysis of variance show that the parameters of the depth of cut (ap ), step over (ae ), feed rate (vw ) and cutting speed (vc ) have a great impact on PM, respectively. Changing these machining parameters leads to severe changes in the PM (0.043–11.200 mg/m3). Also in 78% of experimental tests, the amount of PM is higher than the National Institute for Occupational Safety and Health (NIOSH) standard value (1 mg/m3). In the next step, for the reduction and minimization of PM, a quadratic regression equation was derived. After model validation, the model was minimized by the distance-based optimality method at Minitab software. Optimization result shows that by choosing the optimum parameters ap = 3 mm, vw = 50 mm/s, vc = 15,393 rpm and ae = 6.270 mm, PM is reduced to 0.011 mg/m3, which is much lower (about 89%) than the NIOSH standard value. This prediction was tested and validated by the experimental test.

Study of the influence of the current distortion power of the secondary winding of a transformer on the level of losses in it using the method of experiment planning

Purpose. Detection the relationship between the level of losses of a three-phase transformer and the power of distortion caused by current harmonics.. Methodology. During the research, the methods of determining power losses and additional losses in the elements of the electrical system from higher current and voltage harmonics, the visual programming method, the experiment planning method, and the orthogonal central composite plan method were used. Findings. An analysis of the indicators characterizing voltage and current distortions was carried out, and it was found that these distortions are most fully characterized by the current distortion power and voltage distortion power. These indicators are used to analyze the transmission of electric energy by a transformer of a traction substation. It is noted that the order of harmonics in the distortion power is not eliminated, and higher harmonics are taken into account by the corresponding effective current of higher harmonics. The specifics of the transformer secondary winding connections to the consumer, namely the grounding of one of the secondary winding phases, were taken into account. A number of combinations of current harmonics were used to simulate current distortions. The experiment was carried out using the planning method. The coefficients of the quadratic regression equation that relates power losses to the level of load current harmonics of the third, fifth, and seventh orders are obtaine To determine the significance of the obtained coefficients of the regression equation, the variances and the corresponding values of the Student's criterion were calculated, as a result, factors that do not affect the process and can be excluded from the regression equation were identified. The adequacy of the obtained regression equation was checked by Fisher's criterion. The analysis of the effects and their interaction showed that the standard error of the sample does not exceed 1.66%. As a result of analyzing the combinations of current harmonics that were set during the experiment, it was noted that some of them lead to the same effective phase current, while the power of current distortion is different. The greatest significance of the level of the third harmonic of the current is determined. The constant level of active power on the high voltage side of the transformer is noted, which is due to the absence of voltage distortions on it. Originality. Cases of combinations of current harmonic levels at which the current distortion power index remains unchanged, while the level of transformer power losses caused by current harmonics changes, have been identified. Practical value. This research can be used to assess and reduce the level of power losses in a transformer by filtering certain current harmonics.

Meta analysis of growth performance and immune parameters in freshwater fish fed with dietary supplementation of selenium

ABSTRACT Selenium-based feed supplement is essential for increasing the performance of aquatic organisms. This study aims to analyze and evaluate various data on selenium supplementation in freshwater fish feed by meta-analysis with mixed-model. The study used secondary data from the literature database. Total 27 references containing 125 treatments were analized. Using linear and quadratic regression equations, selenium supplementation in freshwater fish feed resulted in a significantly increased final body weight, weight gain, feed intake, and protein efficiency ratio (P < .05). Then, the GPx activity enzyme in the liver and the increased high-density lipoprotein (HDL) content in the blood of fish exhibited a favorable trend with significantly higher value (P < .05) compared to control fish. However, selenium supplementation could significantly reduce total protein, globulin, low-density lipoprotein (LDL) and cholesterol levels (P < .05). This study concluded that organic selenium supplementation in the range of 0.95 to 6.8 mg/kg feed could improve freshwater fish’s performance.

Force-Velocity Profiling During the Braking Phase of Countermovement Jump: Relationship to Eccentric Strength and Validity of the 2-Point Method.

Nishiumi, D, Yamaguchi, S, Kurokawa, T, Wakamiya, K, and Hirose, N. Force-velocity profiling during the braking phase of countermovement jump: Relationship to eccentric strength and validity of the 2-point method. J Strength Cond Res 37(11): 2141-2148, 2023-The aims of this study were threefold: to investigate the force-velocity profile during the braking phase (bFVP) of the countermovement jump (CMJ) and its relationship with other performance indicators, and whether it could be measured using the two-point method. Sixteen trained men performed 6 different loaded CMJs (0%, 32 kg, 60, 80, 100, and 120% body mass), and eccentric strength measurements were determined. Scatter plots were created using the mean force and velocity during the braking phase of each loaded CMJ. The corrected Akaike's information criterion (AICc) was calculated by fitting linear, quadratic, and cubic regression equations to the bFVP and compared using the 1-way analysis of variance and Bonferroni's post hoc tests. A correlation analysis was performed between the bFVP and other performance indicators. A bias assessment was performed to validate the 2-point method of the bFVP. The significance level was set at p < 0.05. The AICc in the linear regression equation was significantly lower (p < 0.05) than those in the other regression equations. Significant correlations were found between the slope and theoretical maximum force of the bFVP obtained from the linear regression equation and eccentric 1 repetition maximum. The acceptable condition for bias was met by 0-120%. The bFVP is likely to have a linear relationship and can be associated with eccentric strength. Furthermore, the 2-point method in bFVP has validity.

Optimization of influencing factors during co-pyrolysis of biomass and plastics with focus on monocyclic aromatic hydrocarbons content

The thermal conversion of organic solid waste is a relatively economical and feasible method to obtain monocyclic aromatic hydrocarbon. In order to clarify the effect of different temperature, blend ratio and reaction time on the monocyclic aromatic hydrocarbon content during the co-pyrolysis of biomass and plastics, and to seek the best experimental conditions, maize stalk and polystyrene plastic were used as raw materials to analyze the content of monocyclic aromatic hydrocarbons by pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). At the same time, based on the Response Surface Methodology of Central Composite Design, a quadratic regression equation for the co-pyrolysis of maize stalk and polystyrene with focus on content of monocyclic aromatic hydrocarbon was established through the response surface optimization experiment of three factors and three levels. Variance analysis showed that the regression model was significant. The order of influencing factors from high to low on monocyclic aromatic hydrocarbon content was temperature, blend ratio of maize stalk to polystyrene, and reaction time. The optimal experimental conditions were temperature 600 ℃, blend ratio 1:3, reaction time 10.246 s, and the simulated content of monocyclic aromatic hydrocarbons was 68.99%. Based on actual situation, the optimum experimental conditions were temperature 600 ℃, blend ratio 1:3, reaction time 10 s, the theoretical and experimental content of monocyclic aromatic hydrocarbon were 68.31% and 65.68%, respectively. And the error among the simulated, theoretical, and experimental content is also within a reasonable range.

Study on the Temperature Field Change Characteristics of Coal Gangue Dumps under the Influence of Ambient Temperature in Heat Pipe Treatment

In order to investigate the influence of ambient temperature on the temperature field of coal gangue dumps governed by heat pipes (HPs), using self-developed heat pipe and intelligent cloud monitoring software, a 1-year field test was conducted in the spontaneous combustion coal gangue dump of Danao liang. This study analyzed the temperature distribution changes of a spontaneous combustion coal gangue dump under different ambient temperatures, as well as the temperature changes of the coal gangue at different time scales. Correlation analysis between ambient temperature and coal gangue temperature was conducted, and a quadratic regression model was established for goodness of fit and significance testing. The results show that ambient temperature affects the distribution of the temperature field of the spontaneous combustion coal gangue dump under the action of the HPs, and the cooling effect on the high-temperature zone is stronger in autumn and winter. The daily change in coal gangue temperature at each measurement point is similar, showing a peak-shaped curve of low at night and high during the day. The inter-day changes of each measuring point have seasonal characteristics: the cooling rate of the high-temperature zone measuring point is affected by the ambient temperature; the seasonal characteristics of the low-temperature zone measuring point are more obvious than the high-temperature zone, and its daily average temperature is affected by the ambient temperature. The ambient temperature and the internal temperature of the coal gangue dump are correlated, and the quadratic regression equation has a high degree of goodness of fit and meets the F-test, indicating that the quadratic regression model can be used for the empirical regression formula of the ambient temperature and the internal temperature of the coal gangue dump. The results of this study provide some references for the sustainable development of mining environments.

Growth , yield and quality of medicinal plant Chia (Salvia hispanica) as influenced by planting methods and density

An experiment was conducted at Central Research Farm, Gayeshpur, Nadia under BCKV, West Bengal to assess the impact of plant density and planting methods on growth, yield and quality attributes of chia (Salvia hispanica L.) grown during winter (rabi) seasons of 2019–20 and 2020–21. Treatments were distributed in split-plot design, with 2 establishment methods (M1, direct sowing and M2, Transplanting) in main plots and 4 planting density (S1, 60 cm × 50 cm = 33,333 plants/ha; S2, 50 cm × 50 cm = 40,000 plants/ha; S3, 50 cm × 25 cm = 80,000 plants/ha; S4, 50 cm × 20 cm = 1,00,000 plants/ha) in sub-plots. Crop under direct sowing with closer spacing (50 cm × 20 cm) had the greater number of primary branch (15.7/plant), primary branch length (38.4 cm) and main inflorescence length (25.9 cm), thereby reflecting superiority of this treatment combination over others. The same treatment combination produced significantly the highest grain (671.7 kg/ha), stem (1109.4 kg/ha) and husk yield (375.2 kg/ha), which led to increase harvest index (31.2). The greatest economic response in terms of gross return (228.4 × 103 ₹/ha), net return (166.3 × 103 ₹/ha) and B: C ratio (3.67) was recorded in crop under the same treatment combination. Based on quadratic regression equation, the optimum plant density of chia was calculated as 71,428 plants/ha. Thus, direct seed sowing at a density of 71,428 plants/ha (spacing ~ 55 cm × 25 cm) can be done for chia cultivation during rabi season in West Bengal condition.