Row Spacing Research Articles

Modified Double Row Spacing and Fertilizer Rate for Improved Productivity of Glutinous Corn

Various high yielding glutinous corn varieties have been developed and NSIC registered, however, the national and regional yield averages are still very low. A study therefore, was conducted to increase the yield of glutinous corn in Ilocos Norte though modification of planting distance and fertilizer rate. Experimental setups were established for two consecutive dry seasons from 2019-2021 which were laid-out in Split-Plot following the randomized complete block design with three replications using MMSU Glut 1 variety as test plants. Soil pH level of the soil before and after harvest from a depth 0-20 cm and 21-40 cm was increased from 7.26 to 7.52 and 7.33 to 7.60, respectively. MDR plots have higher OM at the 0-20 cm depth by 11.67% to 15.55% as N levels applied increase from 120 to 200 kg N ha-1. At 90 DAE, glutinous corn fertilized with 200-100-100 kg NP2O5K2O ha-1 was significantly taller by 4.2% and 10.77%; higher ear height by 9.6% and 21.40%, longer ear length, and wider ear diameter than those applied with 120-60-60 kg NP2O5K2O ha-1 and unfertilized corn plants, respectively. Heavier ear weight and larger seed size were attained from treatment combination of PD 75 cm x 20 cm and FR of 200-100-100 kg NP2O5K2O kg ha-1 and PD – MDR and FR of 200-100-100 kg NP2O5K2O ha-1. Combination of PD (MDR) and FR 200-100-100 kg NP2O5K2O ha-1 obtained the highest shelling percentage of 93.23%. PD and FR significantly affected the agronomic fertilizer use efficiency (AFUE) of glutinous corn. Application of FR 200-100-100 kg NP2O5K2O ha-1 provided glutinous corn an increased in yield of 17.5% (PD 75 cm x 20 cm), 55% (PD 60 cm x 20 cm) and 105% (PD 80:30 cm x 20 cm) over FR 180-80-80 kg NP2O5K2O ha-1, FR 120-60-60 kg NP2O5K2O ha-1, and the unfertilized, respectively. Treatment combination of PD MDR and FR 200-100-100 kg NP2O5K2O ha-1 gave glutinous corn higher yield by 28.10% using the combination of PD 60 cm x 20 cm and FR 200-100-100 kg NP2O5K2O ha-1 and 29.53% using ...

Support Patterns of Roadways Under Fractured Surrounding Rocks Based on the Quality Level of Rock Mass

The roadway project of broken rock mass in the Shilu Iron Deposit was taken as the research object to discuss the stability control of the surrounding rocks using support patterns with broken rock mass. The grade evaluation of rock mass quality was conducted based on the geomechanical classification of rock mass. The roadway support effect in broken rock mass was calculated. Then, the section convergence characteristics of roadway surrounding rocks were analyzed under the current support scheme using displacement monitoring technology. The conclusions were described as follows: (1) The surrounding rock integrity of the No. 6 and No. 7 transportation roadways in the middle section of the Baoxiu mining area (Level 120) is poor. Based on geological survey data and rock mass classification, the rock mass quality in this region has been rated as Class IV. The joint support pattern of the anchor net and shotcrete was used according to the support guidelines. (2) The parameters for the support structure within Shilu Iron Deposit were designed, according to the requirements, as follows: the use of Portland cement; a shotcrete thickness of 55 mm; resin bolts with a minimum outer diameter of φ 20 mm and a length of 2200 mm; and row and column spacings of 1100 mm each. Meanwhile, a rectangular metal mesh of 80 × 80 mm was used as the anchor mesh. (3) The cross-section displacement reached 20 mm within a week using the support pattern according to displacement monitoring results of the on-site roadway section. Moreover, the convergence deformation rate significantly changed. However, the rate rapidly decreased after the first week, and the cross-section showed no further deformation after one month. The support pattern could control the displacement of surrounding rocks, which was verified by the monitoring results.

On semi-orthogonal matrices with row vectors of equal lengths

When does a rectangular matrix with an orthonormal set of column vectors have row vectors of equal lengths? The column spaces of such matrices are multidimensional generalizations of the projection plane used in isometric perspective. We show that in the absence of unexpected linear relations, any rectangular matrix can be row-scaled so that if we were to orthonormalize the column vectors, the row vectors would attain equal lengths in the process. We use Grassmann coordinates to reduce the question into an instance of the famous matrix scaling problem, and with the help of existing theory introduce simple numerical solutions.

Growth and yield of little millet (Panicum sumatrense L.) as influence by varieties and row spacings under rainfed condition

Growth and yield of little millet (Panicum sumatrense L.) as influence by varieties and row spacings under rainfed condition

Simulation Approaches for the Study of the Oil Flow Rate Distribution in Lubricating Systems with Rotating Shafts

This study addresses the issue of predicting the distribution of lubricant flow through the outlets of a rotating shaft used in vehicle power transmission. A typical geometry with closely spaced rows of holes, suitable for the lubrication of multi-disk clutches, was considered. Both lumped parameter and computational fluid dynamics approaches were applied and compared. The test rig for model validation was designed with a variable speed shaft featuring an axial oil inlet and three equally spaced pairs of radial outlet holes. The main characteristic of the experimental facility is the possibility to selectively measure the flow rates through each outlet. It was found that the three-dimensional model based on the multiple reference frame approach provides a reliable prediction of how the flow rate is distributed. Generally, the flow rate is lower through the outlet closest to the inlet and is maximum at the farthest exit. The flow distribution is minimally affected by the shaft speed. The influence of geometric parameters on making the flow distribution more uniform was studied. It was found that a better flow balance is obtained with a low ratio between the diameter of the radial holes and that of the axial channel. The results obtained offer best-practice guidelines for accurately simulating comparable systems, in order to optimize reliability of the mechanical transmission and energy efficiency of the flow generation unit.

Effect of planting densities by the practice of twin rows on the agronomic and technological parameters of sugar cane in rainfed cultivation

With the aim of improving sugar cane productivity under rainfed conditions, a study of the effect of planting densities using paired rows on sugar cane yield parameters was carried out at the CNRA Ferkéssédougou station in northern Côte d'Ivoire. The experimental design used was a Fischer block, comprising three repetitions of six treatments, designated T1 to T6. The results revealed that treatments T1 and T2 improved cane yields, reaching 149±18.04 and 157±44.55 t/ha, respectively. Similarly, an increase in the number of usable stems per hectare of 207,726 ± 13144.44 and 216,468 ± 70412.15 was noted for treatments T1 and T2 respectively. Furthermore, the T6 treatment improved the technological parameters (Brix (22.4 ± 0.86 %); Fibre content (16.8 ± 0.11 %); Pol (19.4 ± 0.81 %) ; Purity of juice (86.7 ± 1.09 %) ; Saccharin content (14.9 ± 0.62 %); Extractable sugar (10.5 ± 0.52 %)). The study also identified three promising planting densities for village cane :1.1m and 1.3m row spacing at 0.4m and 1.3m row spacing at 0.5m. In conclusion, the cultural practice of density in twin rows in sugar cane plantations in rainfed conditions allows an increase in agronomic and technological parameters. This cultivation practice could contribute to an increase in yield or even a substantial increase in sugar production.

Characterization of early fatigue damage in CFRP unidirectional laminates based on Micro‐CT

AbstractFatigue damages of Carbon Fiber Reinforced Polymer (CFRP) laminates are not obvious. Obtaining the evolution of the internal fatigue damage in CFRP laminates before visible cracks occur is of vital importance for ensuring structural reliability. Micro X‐ray computed tomography (Micro‐CT) can provide micron scale nondestructive imaging of internal structure of materials. In this paper, a preliminary study was conducted on the early fatigue damage evolution of 0° UD laminates. Axial tension‐tension fatigue tests of [0]16 CFRP laminates were carried out, and the evolutionary behavior of damages was confirmed by fatigue dissipated energy. Then, the internal damages of fatigued specimens were observed and reconstructed using Micro‐CT, and statistical parameters such as damage sphericity, length and angle were calculated. The spatial distribution characteristics of cracks were further acquired by surface porosity and frequency distribution of damage positions in ROI. Early damages from tensile‐tensile fatigue in 0° UD laminates extend along the fiber direction with original defects in the interlayer resin enrichment areas as the nucleus, and tend to concentrate near the width edge of the specimens. Finally, a “sandwich” structural model was developed to analyze the internal stresses of laminates under the influence of interlayer resin enrichment. The FEA results revealed that the internal stresses σy and σz concentrate near the width edges of the specimen, resulting in cracks tend to evolve more in the regions close to edges.Highlights Imaging matrix cracks of specimens by Micro‐CT at 12.91 μm voxel size. Demonstrating evolution patterns of cracks with its morphology statistics. Revealing crack distributions in ROIs with variations of surface porosity. Analyzing internal stress distribution by “sandwich” model created from reality.

Improved algorithm for fracture-dissolution pore detection in resistivity imaging logging based on dung beetle optimization

Abstract Resistivity imaging logging has become a direct and precise method for visualizing the structural complexities of reservoir fractures and dissolution pores. The current use of Otsu's thresholding for segmentation results in poor segmentation quality and significant noise. Accurate segmentation of sub-images containing fracture and dissolution pore targets is essential for automated structure identification and subsequent parameter calculation. This study leverages the rapid convergence and robust global optimization capabilities of the Dung Beetle Optimizer to develop enhanced image segmentation approaches. Specifically, it introduces a refined K-Means algorithm for multi-category image segmentation and an Otsu algorithm for multi-threshold image segmentation, both optimized by the Dung Beetle Optimizer. Compared to conventional binary segmentation algorithms, this new algorithm effectively isolates noise and extracts multi-category information. Using the segmented sub-images, this paper integrates mathematical morphology techniques to compute parameters such as area, perimeter, tortuosity length, and pore shape factor for identified targets. Additionally, Principal Component Analysis is used to derive recognition factors for fractures and dissolution pores. Applications show that this factor can identify matrix, fracture, and dissolution pore targets in complex background images. By combining parameter information of the target area, the method effectively removes false information in resistivity imaging and segments sub-images of fractures and dissolution pores, calculating fracture area ratio, dissolution pore area ratio, and total area ratio.

Study on the Method of Vineyard Information Extraction Based on Spectral and Texture Features of GF-6 Satellite Imagery

Accurately identifying the distribution of vineyard cultivation is of great significance for the development of the grape industry and the optimization of planting structures. Traditional remote sensing techniques for vineyard identification primarily depend on machine learning algorithms based on spectral features. However, the spectral reflectance similarities between grapevines and other orchard vegetation lead to persistent misclassification and omission errors across various machine learning algorithms. As a perennial vine plant, grapes are cultivated using trellis systems, displaying regular row spacing and distinctive strip-like texture patterns in high-resolution satellite imagery. This study selected the main oasis area of Turpan City in Xinjiang, China, as the research area. First, this study extracted both spectral and texture features based on GF-6 satellite imagery, subsequently employing the Boruta algorithm to discern the relative significance of these remote sensing features. Then, this study constructed vineyard information extraction models by integrating spectral and texture features, using machine learning algorithms including Naive Bayes (NB), Support Vector Machines (SVMs), and Random Forests (RFs). The efficacy of various machine learning algorithms and remote sensing features in extracting vineyard information was subsequently evaluated and compared. The results indicate that three spectral features and five texture features under a 7 × 7 window have significant sensitivity to vineyard recognition. These spectral features include the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Normalized Difference Water Index (NDWI), while texture features include contrast statistics in the near-infrared band (B4_CO) and the variance statistic, contrast statistic, heterogeneity statistic, and correlation statistic derived from NDVI images (NDVI_VA, NDVI_CO, NDVI_DI, and NDVI_COR). The RF algorithm significantly outperforms both the NB and SVM models in extracting vineyard information, boasting an impressive accuracy of 93.89% and a Kappa coefficient of 0.89. This marks a 12.25% increase in accuracy and a 0.11 increment in the Kappa coefficient over the NB model, as well as an 8.02% enhancement in accuracy and a 0.06 rise in the Kappa coefficient compared to the SVM model. Moreover, the RF model, which amalgamates spectral and texture features, exhibits a notable 13.59% increase in accuracy versus the spectral-only model and a 14.92% improvement over the texture-only model. This underscores the efficacy of the RF model in harnessing the spectral and textural attributes of GF-6 imagery for the precise extraction of vineyard data, offering valuable theoretical and methodological insights for future vineyard identification and information retrieval efforts.

Exogenous application of mepiquat chloride and crop geometry alters cotton growth and yield traits of compact cotton cultivars (Gossypium hirsutum L.)

Mepiquat chloride is widely used as a growth regulator in cotton fields to increase crop yield. The present study investigated the effects of growth regulator (mepiquat chloride) and row spacings on compact cotton's growth and yield attributes. An experiment was conducted during summer and winter seasons of 2023-2024 at Cotton Research Station, Veppanthattai and the field trial was designed as a split-split plot with three main plots (Varieties - CO 17, VPT 2, Suraksha), four sub-plots (crop geometry - 90 x 15 cm, 70 x 15 cm, 90 x 10 cm, 70 × 10 cm), and two sub-sub plots (growth regulators - mepiquat chloride @150 ppm, mepiquat chloride + cyclanilide @400 ppm), each replicated three times. Results concluded that the Suraksha variety showed superior performance with greater plant height, higher biomass, more sympodial branches, higher bolls/m2 and higher seed cotton yield than CO 17 and VPT 2. Wider spacing of 90 cm resulted in greater plant height, more sympodial branches and more bolls/m2 to a significantly rise in dry matter production due to the higher number of plants per unit area. Combining mepiquat chloride with cyclanilide at 400 ppm during square initiation and boll development stages significantly increased sympodial branches and bolls/m2, improving seed cotton yield.In contrast, applying mepiquat chloride alone led to more significant biomass accumulation, increased plant height and longer internodal distances. It was suggested that the Suraksha variety be sown at a spacing of 90 x 15 cm and treated with a combination of mepiquat chloride and cyclanilide. This resulted in a plant architecture well-suited for mechanical harvesting.

Research on the Arrangement Scheme of Spirally Twisted Tape Inserts in a Grate Furnace

To eliminate the flow dead zone and homogenize the asymmetric flow field of a grate furnace, spirally twisted tape inserts (STTIs) with a pitch ratio of 1.5 were installed in the vertical flues of an SCL1000-13.5/450 grate boiler. The arrangement schemes found to be present inside the chosen 1000 t/d grate furnace, determined using the orthogonal experimental method, included separate installation in chamber II, separate placement in chamber III, and simultaneous arrangement in both chamber II and chamber III. The effects of row spacing H, column spacing W, and mounting angle φ were investigated by means of the practicable and feasible numerical simulation method. With a focus on the uniformity degree of the flue gas, the results showed that temperature distribution is directly correlated with the velocity field. When it comes to the uniformity of the flow field, the exclusive use of STTIs in chamber II was better than that in chamber III. Under the optimal combination scheme of STTIs in both chamber II and chamber III (scheme N323), the exhaust gas temperature reached the minimum value and the uniformity index of temperature increased to the range of 0.994~0.997. The findings in this work could provide a reference for the optimization of the flow field in a grate furnace.

Manifestation of selection traits and properties of forage productivity in groups of alfalfa varieties with different resistance to viral and phytoplasma infections

The research was conducted in 2019–2023 in Belgorod region with the purpose of breeding evaluation of alfalfa cultivars with different resistance to «witches’ broom alfalfa» (WBA). Fifty-two selection samples belonging to species Medicago sativa L., M. varia Mart., M. falcata L. The soil is typical chernozem, humus content (according to Tyurin) 4.7…5.0 %, The year of sowing – 2019. Predecessor – pure fallow. Plots – two-row long 3.5 m, row spacing width – 0.3 m. Repetition – five times. Standard – variety Belgorodskaya 86, sown through 5 numbers. Seeding rate of 100 germinated seeds per 1 linear meter. It was found that the group of varietal samples (n = 10) with low resistance to WBA (variation of prevalence 24.3–34.9 %) is characterized by a greater accumulation of protein (by 44.6 g/kg, t = 8.0, p 0.05), higher foliage (by 4.8 %, t = 3.7, p 0.05) and height (by 25.3 cm, t = 6.2, p 0.05), compared to the group of varieties resistant to WBA (n = 12) (prevalence variation 4.6… 9.1 %). Varieties with high resistance to WBA, belong to yellow and yellow-hybrid alfalfa varieties: Pavlovskaya 7, PO-172, Marusinskaya 425, PO-173, Sarga, PO-174, Victoria, 20–89 H, 193–95d, PO-175, SGPR-8, Vela×Sarga. Varieties with low resistance to VML belong to blue alfalfa and partially – blue-hybrid varieties: Krasnoyaruzhskaya 2, SI-139, SI-138, Plateau, Verko, Luzelle, Salsa, Kreno, Galaxi, Planet.

Effect of Different Weed Management Practices on growth and yield in Potato at Khumaltar, Lalitpur, Nepal

Potato (Solanum tuberosum L.) is the fifth most important crops in the world in terms of production with an estimate of 375 million metric tons. In Nepal, potato ranks second in terms of production and sixth in terms of area coverage. Potato production is affected by weed infestation. Weeds compete with crops for nutrients, water and other resources, which eventually reduce the crop yield. The critical period of crop-weed competition for potato is 25-40 days from planting depending on the climatic-zone and planting seasons. The most common method of weed control in Nepal is manual method, while herbicides are uses in less areas. Weeds are considered as the major problem in conventional and organic farming, due to lower yields by weeds and higher costs of labor for weed control. Mulching is one of the best and safest practice for effective weed management in potato due to which micro-climate manipulation is developed. Metribuzin is widely used herbicides in potato that controls a range of broadleaf weed species and suppresses many grassy weeds. To study the performance of different weed management practices in potato ten treatments were set up viz., three herbicides (pendimethalin@ 1.0 kg a.i ha-1, metribuzin@ 0.5 kg a.i ha-1 and atrazine @ 0.25 kg a.i ha-1) constituting seven treatments, one mulching with rice straw, one treatment with two manual hoeing, and another treatment with no any weed management practices as control.The treatments were laid out in RCB design with 4 replications. The potato variety Janak Dev was planted on 12th Feb 2021 and 23rd Jan 2022 with tuber rate of 4.1 t.ha-1 with row spacing of 60 cm and plant to plant 20 cm in a plot size of 4 x 3 meter in flat bed. Growth parameters such as plant height, plant fresh and dry biomass were recorded. Data on weed density, weed dry biomass, and tuber yield were taken.The economics of the different treatments were calculated. Among the treatments metribuzin@ 0.25 kg a.i ha-1 as pre-emergence proved effective in controlling weeds showing highest weed control efficiency (200.7 %) and tuber yield (32.79 t ha-1) . However, the treatment rice straw mulch @ 6 t ha-1 produced the highest tuber yield (38.31 t ha-1), 73.4 % increased yield over control, weed control efficiency(147.1%), economic benefit (NRS 13,40,850), benefit cost ratio (4.93).The treatment rice straw mulch @ 6 t ha-1 showed superiority among the different weeds management practices.

Atomic force microscopy wide-field scanning imaging using homography matrix optimization

During the offline combination of multiple atomic force microscopy (AFM) images, changes in probe displacement can be affected by dynamic noise, leading to dislocation and tearing in the stitching. To overcome this, we designed a homography matrix optimization method to describe the relative positional relationship between images by constructing the original image matrix and applying singular value decomposition to denoise the homography matrix. Additionally, we implemented a scale-invariant feature transform (SIFT) to extract feature points. To verify the effectiveness of this method, the SIFT + RANSAC (R), SIFT + affine transformation (AT), and oriented FAST and rotated BRIEF (ORB) algorithms were compared with the proposed algorithm. The experimental results demonstrate that the proposed method precisely computes the transformation matrix, thereby guaranteeing the geometric consistency of mosaic imaging. The proposed method preserves the intricate details of the original image and enhances the stitching quality of wide-field images.

Narrow rows increase maize grain yield regardless of plant density in a Mediterranean environment

Abstract The spatial distribution of maize plants influences the number of kernels set per plant by modifying the radiation environment during the critical period for kernel number determination. A two-year field experiment was conducted in Sardinia to explore whether, in a Mediterranean environment, a reduction in row distance can have a positive effect on grain yield of full-season maize hybrids and, if it does, whether this effect is also affected by plant density. Treatments were a factorial combination of three plant densities (6, 8 and 10 plants/m2) and two row spacings (35 and 70 cm). Grain yield and grain number benefited from a reduction in row distance from the canonical 70 cm to 35 cm irrespective of plant density and yield level (14.7 t/ha on average in 2021, 9.9 t/ha in 2022 vs 13.7 and 8.8 t/ha with canonical row distance). Row distance did not affect either the coefficient of extinction of radiation or the intercepted photosynthetically active radiation (PAR) during the critical period for grain number determination. The higher grain number per unit area at the smaller row distance translated into a greater grain yield, which cannot solely be attributed to radiation interception and plant growth rate during the period of kernel number determination. Halving the common row distance is a valuable management option for full-season hybrids grown in Mediterranean environments without nitrogen and water limitations as it seems capable of increasing grain yield via an increase in kernel number per unit area, regardless of plant density and yield level.

Design and Testing of a Crawler Chassis for Brush-Roller Cotton Harvesters

In China’s Yangtze River and Yellow River basin cotton-growing regions, the complex terrain, scattered planting areas, and poor adaptability of the existing machinery have led to a mechanized cotton harvesting rate of less than 10%. To address this issue, we designed a crawler chassis for a brush-roller cotton harvester. It is specifically tailored to meet the 76 cm row spacing agronomic requirement. We also conducted a theoretical analysis of the power transmission system for the crawler chassis. Initially, we considered the terrain characteristics of China’s inland cotton-growing regions and the current cotton agronomy practices. Based on these, we selected and designed the power system and chassis; then, a finite element static analysis was carried out on the chassis frame to ensure safety during operation; finally, field tests on the harvester’s operability, stability, and speed were carried out. The results show that the inverted trapezoidal crawler walking device, combined with a hydraulic continuously variable transmission and rear-drive design, enhances the crawler’s passability. The crawler parameters included a ground contact length of 1650 mm, a maximum ground clearance of 270 mm, a maximum operating speed of 6.1 km/h, and an actual turning radius of 2300 mm. The maximum deformation of the frame was 2.198 mm, the deformation of the walking chassis was 1.0716 mm, the maximum equivalent stress was 216.96 MPa, and the average equivalent stress of the entire frame was 5.6356 MPa, which complies with the physical properties of the selected material, Q235. The designed cotton harvester crawler chassis features stable straight-line and steering performance. The vehicle’s speed can be adjusted based on the complexity of the terrain, with timely steering responses, minimal compaction on cotton, and reduced soil damage, meeting the requirements for mechanized harvesting in China’s inland small plots.

Introduction and Agrotechnology of Greek Chambala (Trigonella Foenum-Graecum L.) in Surkhondaryo Region

This research explores the introduction and agrotechnology of Greek Chambala (Trigonella foenum-graecum L.) in the Surkhandarya region of Uzbekistan. The study focuses on the growth development and medicinal properties of this leguminous herb, with particular emphasis on agrotechnological factors such as planting dates, row spacing, and chemical protection measures that influence productivity. Greek Chambala is valued for its bioactive compounds, known for medicinal benefits like managing diabetes and obesity. The experiment was conducted at the "Jonchekka Sarhadlari" farm using different planting configurations and fertilization methods. The results showed that planting in November yielded optimal seed development and contributed to soil fertility through nitrogen fixation. The findings provide practical insights for enhancing the cultivation of Greek Chambala in Surkhandarya's climatic conditions, making it a promising crop for both agricultural and medicinal purposes.

Failure mechanism of severe deformation in gob-side entry rib and unloading-supporting coupling control technology

Given the problem of the solid coal side produces strong mine pressure in the stage of strong mining and lagging dynamic pressure in the gob-side entry retaining (GER). Using the W3233 ventilation roadway in the West-Third mining area as a case study, the research employs numerical simulation, field observation, and engineering analogy. Key findings include: (1) The optimal plan reduces maximum stress on the coal side and shifts it inward, primarily by severing the main roof and alleviating the gangue wall load, offering limited pressure relief on the solid coal rib. (2) When hole-creating depth is too close to the solid coal rib (b = 6 m), it compromises integrity. If the depth exceeds the stress maximum region (b = 10 m), it fails to effectively sever the peak stress area. However, a depth within the stress maximum region (b = 8 m) effectively absorbs and transfers stress, with a buffer area of approximately 3.7 m from the external support area. (3) The length of the hole (l = 2, 4, 6 m) directly affects deformation absorption and pressure relief, while longitudinal row spacing (s = 2.7, 3.6, 4.5 m) has an inverse effect. For optimal results, a hole length of 4 m and a row spacing of 3.6 m are recommended. (4) After 150 days, the new bag pressure regulating system maintains about 40 % of the absorbable deformation space in the LPRH, confirming simulation results. Observations show that external support forces remain stable at around 250 kN, and coal rib displacement is controlled within 350 mm, over 65 % less than similar GER sections with comparable geological conditions. This research introduces a novel technology and methodology for managing large deformations of the solid coal rib in gob-side dynamic pressure roadways, providing significant reference value.

Elimination and Factorization

Summary If a matrix A has rank r, then its row echelon form (from elimination) contains the identity matrix in its first r independent columns. How do we intepret the matrix F that appears in the remaining columns of that echelon form? The matrix F multiplies those first r independent columns of A to give its n–r dependent columns. Then F reveals bases for the row space and the nullspace of the original matrix A. And F is the key to the column-row factorization A = CR .

Cyclic shift short-distance attention for defect detection of fine etching mesh

Abstract Based on the deficiency of the existing Swin Transformer in the detection of surface defects in metal etched grids, i.e. the isolation of information transmission between different windows, and the limitations of image matrix size and network structure,which make it not suitable for long sequence data processing and dense prediction scenarios, a defect detection method for metal etching nets based on Cyclic shift Long Short Distance Attention (C-LSDA) is proposed. In the proposed method, cross-scale features are used to capture long and short distance relationships,and enhance the feature transfer between windows. Tracking position bias (TPB) is also used to improve relative position bias (RPB), in order to help the model to better understand the spatial relationships in the input data. In addition, the image is downsampled at various scales, so that the proposed method can be suitable for long sequence data processing and dense prediction scenarios. In order to improve the detection accuracy of small targets. a multi-feature fusion pyramid network (MFFPN) for feature fusion is also proposed. The experimental results show that the proposed method is significantly superior to the traditional CNN recognition method and the transformer recognition method. The proposed methodhas good identification accuracy and low computational cost.