Heavy Disk Research Articles

An Aero Engine Disk Sizing and Weight Estimation Approach with Improved Temperature Profiles

Abstract During the predesign phase of an aero engine, interdisciplinary parametric studies are crucial for identifying an optimum engine. As innovative engine concepts emerge, it is essential to study trends aiming to minimize climate impact and one of its key contributors, fuel burn. The comparatively heavy disks, subjected to high thermal and mechanical loads, are central to this analysis due to their high impact on the overall module mass. This paper proposes an approach to achieve a first lightweight mechanical design of disks in the predesign phase. Based on a performance and aerodynamic baseline, the design space and physical boundary conditions are set. Firstly, an initial mass optimized disk is derived using simplified temperature profiles and stress calculations under the Mechanical Design Point conditions. Subsequently, all the module disks are considered and an estimation for each bore temperature is achieved through a novel loop over the entire module and all available operating points. By evaluating the temperature and stress profiles across various operating conditions, the lowcyclefatigue life of each disk can be studied. As part of a highly modular engine predesign framework, this method allows for zooming capabilities of single disk calculations by prescribing individual boundary conditions. The proposed approach already yields an initial assessment of the rotors within a short runtime, facilitating simple iterations with the succeeding design phases due to method and tool commonalities. While the primary focus of the current work is on compressor design, the principles presented are adaptable and expandable to turbine disk applications as well.

Water consumption of corn under different methods of primary tillage after row-crop predecessors on an energy-storage soil maintenance system

The object of research was the light chestnut soil of the Chokh Agrofirm of the Gunibsky district in the Kizilyurt transhumance zone of the Republic of Dagestan. The humus content in the arable layer is 2.77%, P2O5–2.21, K2O – 32.8 mg/100 g, the density of the arable soil layer is 1.24 g/cm3, the lowest moisture capacity (MC) is 29.2% (layer 0–0.6 m). The effectiveness of two row-crop predecessors was studied: sunflower for seeds and corn for grain, and the use of skimmers in the main tillage for corn. Soil moisture, watering and irrigation standards, incoming and outgoing items of the water balance and the coefficient of water consumption for corn were determined. In the second ten days of May, the plant remains of predecessors were crushed using double disking with heavy disc harrows BDT-3, plowing was carried out to a depth of 0.28–0.30 m with a PLN-4-35 plow with and without skimmers, the field was leveled with a small leveler MV – 6 and watered at the rate of moistening the soil layer of 0–0.6 m in strips with lateral release of water manually, vegetation irrigation was carried out in furrows. Sunflower sowing was carried out with seeds of the VNIIMK-8883 variety, corn – hybrid ROSS-299, the seeding rate for both crops was 72 thousand seeds/ha. Fertilizers for sunflower were applied at the rate of N90Р40К90, including N40Р24К74for plowing, N16Р16К16– when sowing with seeds, N34for fertilizing in the phase of 5–6 leaves when cutting furrows, for corn – N90Р40, of which N40Р24for plowing, N16Р16К16when sowing with seeds, N30in fertilizing in the phase of 3–5 leaves. It has been established that in the areas of irrigated agriculture of the Western Caspian region, when selecting row-crop predecessors for corn for grain, preference should be given to early-ripening varieties of sunflower for seeds, which are harvested in the third decade of July, and after harvesting it remains in the soil more than 15 t/ha of plant mass. At the same time, the maximum corn yield is achieved – 9.16 t/ha of grain, exceeding the control by 33.1%, due to which, with the same total water consumption as the control option, the water consumption coefficient is reduced by 23.7%.

Effect of Cultivation Methods on Structural Elements and Grain Yield of Winter Wheat

The main part of human food is wheat, and the main task facing agriculture is to obtain high-quality grain from a single field in the current conditions. Yield varies depending on the variety, soil and climatic conditions and the cultivation used. Taking these into account, our research studied the structural elements and yield of winter wheat against the background of predecessors, soil cultivation and nutritional conditions in dry rainfed conditions, and the 3-year average result is also given in the article. For the first time in the region, optimal nutritional conditions and soil cultivation were studied by minimizing soil cultivation based on its predecessor and replacing some mineral fertilizers with organic fertilizers in order to obtain both high and quality grain products through efficient use of land. The studies were conducted in a 3-factor (2×3×3) field experiment in a short-rotation cropping turnover (peas, wheat, wheat) located in the Jalilabad Regional Experimental Station in the dry rainfed conditions of South Mugan. The object of research is the fertile 95 durum wheat varieties. Structural analysis of the yields was carried out on samples of sheaves taken from 1 m2(4×0.83×2×0.15 m) in two rows of 83 cm in 4 different replicate locations. After the shave samples were taken, the yield of the grain was determined according to the cultivation options by harvesting directly in each field with a combine. From the 3-year average results of the study for 2019-2021, it was found that the structural indicators of the variety and grain yield were dynamic depending on the cultivation option. However, the highest results were obtained after the pea predecessor against the background of N60P60+10 tons of manure applied with a heavy disc harrow at a depth of 10-12 cm in the twice disc option.

The Behavior of Some Alternative Crops Under the Synergic Effect of Soil Work and Climate Conditions in the Eastern Area of Romania

Water and thermal stress accentuated in the last decade, hinder farmers from obtaining rich and balanced harvests in the quality-quantity ratio. Thus, it is studied to carry out minimal soil work and to cultivate a wide range of agricultural species that have increased adaptability to climate changes. Dry farming is one of those working systems that allow the exploration of several combinations of soil works and rarely cultivated plants that can replace conventional crops. The present experiment was carried out to observe the influence of tillage on the yield of some alternative types of grassy cereals cultivated under water and thermal stress conditions in the eastern part of Romania, in the 2020-2022 agricultural years, at A.R.D.S., Braila. Rye and triticale crops were sown in three repetitions for each tillage: L1 – Plow (control), L2 – Paraplow, L3 – Scarifier, L4 – Heavy Disc, and L5 – No Tillage. The 2020-2021 agricultural year was rich in precipitation, therefore the difference in yields, for L2, L3, and L4 tillage compared to control - L1, was between -540 kg/ha and +267 kg/ha for the rye crop and between 0 - 535 kg/ha for triticale crop. Climatic conditions influenced yields, especially for triticale crops.

Effect of Land Ploughing Methods and Leveling Techniques on Wheat Production in the Upper Terraces of the Northern State - Sudan

Precision land leveling must be treated as a precursor technology for improving crop yield, enhancing input-use efficiency and ensuring long-term sustainability of the resources. A field experiment was conducted in Dongola Agricultural Research Farm, Northern State, for two successive seasons to investigate the effect of three type of ploughing; heavy disc harrow (H1), disc plough (H2) and no-ploughing (H3), and three land leveling techniques, Laser (L), Scraper (S) and traditional (T),on wheat production. The experiment was arranged in a strip split plot design and the treatments were replicated three times.
 The results indicated that effective field capacity, fuel consumption, and slippage were significantly affected by ploughing method. Laser land leveling recorded the highest fuel consumption (16.3 L/hr), and the lowest field efficiency (55%). while the heavy disc harrow recorded the highest effective field capacity (0.98 ha/hr), field efficiency (71.2%) and wheel slippage (8.1%). The soil moisture content (db %) was increased with time and depth. The highest mean soil moisture content was obtained with the laser land leveling and heavy disc harrow treatment at 75-100cm soil depth as 24.82%. The results revealed that the highest average grain yield (4.63 ton/ha) and infiltration rate (31cm/hr) were also recorded by the laser land leveling and heavy disc harrow. The treatments showed significant differences at the 5% level between the treatments for the parameters measured. Multiple regression analysis showed a highly significant effect (P≤ 0.001) of laser leveling with disc harrow ploughing on grain yield, compared to the other treatments used in the study (R2 = 0.40). The relation between the grain yield (Y) and the treatments: X1 ploughing, X2 leveling is summarized in the following equation: 
 Y = 2.875 + 0.552X1 + 0.254X2
 The study concluded that, although Laser leveling has increased the grain yield with high cost, yet it is not an expensive technique when the cost is distributed over the period of Laser leveling. The highest grain yield was obtained by the heavy disc harrow with laser land leveling.

Reserves of available soil moisture, productivity and mass of root residues of winter wheat and post-harvest white mustard depending on cultivation, precursors and fertilizer

Three-year (2020–2022) research at the experimental field of Bila Tserkva National Agrarian University, make it possible to calculate the economic and energy efficiency and to recommend a differentiated system of the main tillage on typical deep, low-humus medium-loamy chernozems of the Right Bank Forest-Steppe of Ukraine in a five-field specialized (cereal) crop rotation, which involves deep plowing only for row crops, and for winter wheat after both predecessors (peas and buckwheat) and post-harvest mustard for green manure cultivation with heavy disc harrows, respectively, to a depth of 8–10 and 10–12 cm with the introduction of N140P60K100 under the bread plant and N120P60K90 – after peas, and under cabbage – N80P60K80 after both predecessors. For the placement of winter wheat after legume and cereal crops and recommended agricultural measures, the cost of one ton of grain was 3.82 and 4.06 thousand hryvnias respectively, conditional net profit was 18.11 and 16.06 thousand hryvnias/ha, profitability 44.4 and 37.1 %, energy efficiency ratio 2.4 and 1.9. Reserves of available soil moisture under winter wheat are higher in the link with peas than buckwheat. The highest reserves of it in the upper, arable and meter layers in the seedling phase of the culture after both predecessors under differentiated cultivation in crop rotation. In the phase of entering the tube, this indicator is the lowest in the arable layer under differentiated, and in the meter layer - under disk cultivation in crop rotation. On the date of sowing white mustard in the row with peas, the reserves of available soil moisture in the upper layer differed insignificantly according to tillage options, and in arable land they are the highest under shelf-disc tillage. In the meter layer, this indicator did not undergo significant deviations from the control, although it increased compared to it by 1.2–2.5 mm. For the predecessor of buckwheat, the content of soil moisture in the investigated layers (0–10, 0–30 and 0–100 cm) on the date of sowing white mustard increased significantly under differentiated and decreased significantly under disk tillage. In the upper layer of the soil, this indicator is slightly higher in the link with peas (by 0.5 mm), in the arable one with buckwheat (by 2.6 mm), and in the meter layer – it is almost the same for both predecessors. The yield of winter wheat is 0.59 t/ha higher in the link with peas than with buckwheat. After both predecessors, it is the largest under differentiated cultivation of fertilized and unfertilized plots. With chisel-disk and disk processing, this indicator is significantly reduced. Only on unfertilized plots under shelf-disk and disk tillage, the yield of green mass of white mustard is higher in the link with peas than with buckwheat, in the remaining variants of the experiment, the preference is for the grain predecessor. This indicator in the link with peas decreased, for all tillage options, compared to the control, but significantly only for disc tillage. In the link with buckwheat, its significant decrease is observed under disc cultivation and a significant increase under differentiated cultivation of fertilized areas. The dry mass of root residues of winter wheat is significantly lower for chisel-disc and disc than for shelf-disc treatments in both predecessors. Under differentiated processing, this indicator increased, compared to the control, but insignificantly. The mass of the dry root of white mustard in the link with leguminous crop is less for all tillage options, compared to the control, but it is significantly (by 0.19–0.25 t/ha) less for discing the soil. With an increase in fertilizer application rates, the dry weight of the root residues of the studied crops grows more slowly than the yield. At the same time, a slower growth of both above-ground and underground mass of both agrophytocenoses was established for placing them after the leguminous than for the cereal predecessor. Calculations of economic and energy efficiency give reason to recommend a differentiated system of the main soil cultivation on typical deep, low-humus, medium-loam chernozems of the Right Bank Forest Steppe of Ukraine in a five-field specialized (cereal) crop rotation, which involves deep plowing only for row crops, and for winter wheat after both predecessors (peas and buckwheat) and post-harvest mustard for green manure tillage with heavy disc harrows, respectively, to a depth of 8–10 and 10–12 cm with application of N140P60K100 under the bread plant after 1 buckwheat and N120P60K90 – after peas, and under cabbage – N80P60K80 after both predecessors. For placing winter wheat after leguminous and cereal crops and recommended agromeasures, the cost price of one ton of grain was UAH 3.82 and 4.06 thousand respectively, conditional net profit was UAH 18.11 and 16.06 thousand/ha, profitability 44.4 and 37.1 %, energy efficiency ratio 2.4 and 1.9. Key words: soil, cultivation, productivity, fertilizers, predecessors, cultures, root residues, crop rotation.

МЕТОД РАСЧЕТА ВЫБРОСА ДИОКСИДА УГЛЕРОДА МАШИННО-ТРАКТОРНЫМИ АГРЕГАТАМИ НА ТЕХНОЛОГИЧЕСКИХ ОПЕРАЦИЯХ, С УЧЕТОМ ВЛИЯНИЯ ПАРАМЕТРОВ АГРЕГАТОВ НА ФОРМИРУЕМЫЙ УРОЖАЙ ЗЕРНОВЫХ КУЛЬТУР

Researches were conducted for the purpose of development of a method of calculation of emission of carbon dioxide by machine and tractor units on technological operations in crop production at cultivation of grain crops. The criterion of optimization of parameters and operating modes of soil-cultivating, sowing and other units – the minimum emission of carbon dioxide in the atmosphere at their production, maintenance and production operation is offered. Feature of the offered method is the fact that it considers the influence of parameters of the equipment on losses of a potential harvest which to avoid at today's level of development of the equipment and technologies it is impossible. Formation of a harvest results from absorption by carbon dioxide plants from the atmosphere and, partially, from the soil. Carbon dioxide (CO2) which the lost harvest could absorb from the atmosphere is removed from a circulation, so remains in the air, and in our technique it is attributed to CO2 released into the atmosphere at production, service and operation of the unit. In article the method of calculation of the amount of the carbon dioxide necessary for the formation of unit of a grain part of a harvest and not grain part accompanying it is in detail considered. The formula which allows to calculate the mass of carbon dioxide in kg for the formation of grain weighing 1 kg is offered. It became clear that from grain crops on formation of unit of a harvest, most of all CO2 from the atmosphere is absorbed by winter rye (about 3 kg/kg), further corn (2.8 kg/kg by theoretical calculations). Leaning on these researches, the mathematical model of operation of machine and tractor units on technological operations on preparation of the soil for crops and crops by the offered criterion of optimization is developed. An inspection of operability of the offered method by carrying out computing experiments with use of the created mathematical model on technological operation – preparation of the soil heavy disk harrows is carried out. During calculations of influence weight of the tractor, power of its engine, width of capture of the unit and working speed of the unit on carbon dioxide emission became clear. The minimum emission of carbon dioxide, for conditions of carrying out a computing experiment, is provided weighing tractor of 145 kN. The tractor weight deviation towards increase or reduction leads to growth of emission of carbon dioxide in the atmosphere.

Coupled Thermal Stress Analysis of Volvo Truck Disc Brake

This paper deals with the coupled thermal structural analysis developed in Volvo heavy truck disc brake as a function of disc thickness and braking time. A ventilated type of disc brake was employed by having vents (holes) on its surface, which needs a cooling system. When the brake pedal is applied, the friction between the disc and pad tremendously increases due to the heat generated in this system. This heat was partitioned into two contacting bodies (disc rotor and pad). Both analytical and numerical approaches were used to carry out the analysis. Analytically, the transient temperature obtained by the partial solution approach and the stress field were evaluated by the elastic von Mises criterion. In the numerical approach, temperature and stress response were analyzed by the explicit standard ABAQUS. From both results, high thermal gradient and von Mises stress distribution were observed at the sharp edges of the disc, which causes a decrement in braking efficiency and an overall drop in braking performance.

Robotic replacement for disc cutters in tunnel boring machines

Disc cutters are representative cutting tools in tunnel boring machines (TBMs). They are installed at the cutter head of the TBM to disintegrate rocks during tunnel boring. Disc cutters require regular replacement to avoid wear and malfunctions. Currently, most replacement work is performed manually, with intensive labor requirements and hazardous working conditions. To solve these problems, we proposed a robotic solution for disc cutter replacement in a widely used TBM. We used a novel eccentric-locking mechanism to simplify the disc cutter installation and developed a robotic manipulator with high dexterity and a high payload capacity for moving heavy disc cutters within the highly constrained TBM chambers. The proposed system can be operated through a specially designed teleoperation platform, either manually or semi-autonomously. We fabricated and tested a prototype in a laboratory environment and applied it to a real TBM. The results confirm the effectiveness and efficiency of the robotic solution.

Effect of main cultivation methods in dry rainfed conditions on the amount of weed under winter wheat

Relevance. Against the background of predecessors, soil cultivation and nutritional conditions, weeding of the area under Barakatli 95 durum wheat variety was studied and the results obtained are given in the article. Thus, high weeds in the field reduce the quantity and quality of crops. One of the main factors preventing this is the application of proper cultivation methods appropriate to the region. This is one of the most important and urgent issues in agriculture.Methodology. The research was conducted in a 3-factor (2×3×3) field experiment in a short-rotation crop rotation (pea-wheat-wheat) located at the Jalilabad Regional Experimental Station in the rainfed conditions of South Mugan. The amount of weeds in the field was studied in the first decade of March and April by counting weeds per 1 m2 from different parts of the field according to the options.Results. The results of the 3-year study (average for 2019–2021) showed that the effect of predecessors, soil cultivation and nutritional conditions on the amount of weeds under winter wheat was different. Among the cultivation options, relatively high weeding soil was obtained with a heavy disc harrow at a depth of 10–12 cm in the form of 1 disc, and against the background of feeding conditions, N60P60 + 10 tons of manure on all three cultivations, and the least weeding was observed in the variant where N90P60K45 fertilizer norm was applied in 2 discs at a depth of 10–12 cm with a heavy disk trowel after the pea predecessor.

Mudanças no estoque de carbono orgânico e produtividade de culturas em solo arenoso tropical sob sistemas de produção de grãos-algodão em sequeiro na Bahia, Brasil

ABSTRACT Most studies about soil organic carbon stock changes in the Cerrado (Brazilian Savanna) biome are either related to field data collected in clayey Ferralsols or different land uses, as if they were in equilibrium. This study aimed to evaluate the effect of tillage systems and crop sequences on the soil organic carbon stock and crop yield, in a sandy Ferralsol from Bahia, Brazil. The experimental design was randomized blocks, with four replicates. Soil samples were collected after fve years of cotton, soybean and maize monocropping under heavy disk harrow and leveling harrow (conventional tillage), and of crop rotation of cotton, soybean and maize with green manure or cover crop (no-tillage). Additional samples were collected from a non-cultivated site (Neotropical Savanna, Cerrado sensu stricto). Soil conservation practices such as no-tillage and crop rotation with cover crop and green manure favored the soil organic carbon stock at the 0-40 cm layer, with the highest values reaching 36.03 Mg ha−1. The accrued soil carbon stock under conventional tillage and monoculture of cotton, maize and soybean was lower than under no-tillage, which ranged from 30.9 to 54.9 %, with the soil organic carbon stock increasing at the annual rate of 2.36 Mg ha−1 during fve years. The no-tillage, with the soybean-maize-cotton rotation, in combination with cover crop and green manure, increased the cotton and soybean yields, with a simultaneous organic carbon accumulation in the sandy soil.

Soil density, soil moisture content and maize yield using No-till technology of cultivation

The research was carried out at the experimental field of the North Caucasus Federal Research Center. In the field, years of experience, founded in 2012, in crop rotation of soybean-winter wheat-sunflower-corn all crops cultivated on the recommended scientific institutions technology soil treatment, and these same crops in the same crop turnover has grown by No-till technology. The recommended technology of maize cultivation consisted of soil double tillage by the heavy disk tools to the depth of 0.120-0.140 m immediately after harvesting the previous sunflower, winter plowing at 0.200-0.220 m, early spring harrowing, pre-sowing cultivation and sowing with an Optima seeder. In the No-till technology, the soil was not treated and ten days before corn sowing, the plots were sprayed with a continuous herbicide Rap 600 at a dose of 2 l/ha. The research showed that better accumulation and conservation of moisture can be provided during the flowering of maize with the content in the soil layer of 1.5 m at the depth of 34 mm, or 18.1% more moisture than usage of the technology with tillage which is recommended by scientific institutions. It contributes to a significant increase of 0.42 t/ha, or 12.0% in crop yield by using this technology.

Investigation of the damping properties of the process module for a tractor of traction class 1.4

To analyze the positive influence of the technological module on the fluctuations of the external load of the tractor, the methods of statistical dynamics are used. A dynamic model of a process module with two rotating masses is considered: the rim and tire of the drive wheel and the translational mass of the process module. Using the transfer function, the spectral functions of the output process (the horizontal component of the force on the MTZ-82 tractor) were determined when performing a machine-tractor unit (MTA) technological operation with heavy disks (BDT-7) intended for a class 3 tractor. The developed mathematical model of the technological module allowed us to construct theoretical spectral densities of the horizontal component of the force on the tractor hitch when completing it with the technological module. The use of the process module allows the frequency range of forces on the tractor hitch to be shifted to a lower zone from 0 to 2.5 Hz, excluding high-frequency components compared to the standard configuration of the tractor.

РАСШИРЕНИЕ ТЕХНОЛОГИЧЕСКИХ ХАРАКТЕРИСТИК БОРОНОВАЛЬНОГО АГРЕГАТА

Improving the quality of pre-sowing tillage is a priority direction. Harrowing with the use of heavy disc harrows is one of the operations of pre- sowing tillage. An important task when using heavy disc harrows is to ensure sufficient load on the working body. (Research purpose) The research purpose is in increasing the efficiency of the harrowing process by adjusting the coupling weight in the tractor–harrow link using special devices. (Materials and methods) It is important to match the necessary condition of balance between the load on the working body and the traction qualities of the tractor with a low load- bearing capacity of the soil. The article describes a regulator of the coupling weight of the harrowing unit, for which was applied a patent. The article presents the general types of connection of the device with the disk harrow frame. (Results and discussion) The proposed device allows you to redistribute the weight of the unit, thereby automatically changing the load on the working body. Authors performed experimental studies on the influence of the main design parameters of the devices on the operation of the machine and tractor unit. (Conclusions) The proposed device allows, by expanding the design and technological parameters, to regulate the depth of processing, traction characteristics and speed of the harrowing unit.

РАСШИРЕНИЕ ТЕХНОЛОГИЧЕСКИХ ХАРАКТЕРИСТИК БОРОНОВАЛЬНОГО АГРЕГАТА

Improving the quality of pre-sowing tillage is a priority direction. Harrowing with the use of heavy disc harrows is one of the operations of pre-sowing tillage. An important task when using heavy disc harrows is to ensure sufficient load on the working body. (Research purpose) The research purpose is in increasing the efficiency of the harrowing process by adjusting the coupling weight in the tractor-harrow link using special devices. (Materials and methods) It is important to match the necessary condition of balance between the load on the working body and the traction qualities of the tractor with a low load-bearing capacity of the soil. The article describes a regulator of the coupling weight of the harrowing unit, for which was applied a patent. The article presents the general types of connection of the device with the disk harrow frame. (Results and discussion) The proposed device allows you to redistribute the weight of the unit, thereby automatically changing the load on the working body. Authors performed experimental studies on the influence of the main design parameters of the devices on the operation of the machine and tractor unit. (Conclusions) The proposed device allows, by expanding the design and technological parameters, to regulate the depth of processing, traction characteristics and speed of the harrowing unit.

Humus condition under different systems of basic cultivation of dark gray forest soil

Studies, were conducted in a stationary experiment between 1988 and 2018 on dark gray forest heavy loam soil in Scientific Research Institute of Agriculture for Northern Trans-Ural Region - Branch of Federal State Institutions Federal Research Centre Tyumen Scientific Centre of Siberian Branch of the Russian Academy of Sciences. The aim of the study is to determine the effect of long-term (30 years) impact of different systems of basic cultivation of dark gray forest soils in the cultivation of grain crops on the humus content. Observations were made according to generally accepted methods during 6 rotations of grain and fallow crop rotation: bare fallow, winter rye, spring wheat, spring vetch, spring barley, unfolded in time and space. The impact of the combined system of tillage with alternation of plowing and no-tillage at 20-22 cm during 6 rotations of a 5-pole grain and steam crop rotation (30 years), increased the humus content in the 0-40 cm layer of dark gray forest soil compared with the initial content by 0.42%. The systems of main tillage - differentiated, without sowing, and mouldboard provided in general a relatively favorable dynamics of the humus state of the soil. The content of humus in the 0-40 cm layer of soil by differentiated and unswept systems during the study period remained close to the initial condition. По отвальной системе содержание гумуса снижалось на 0,22% или в среднем 0,37т/га в год. The greatest loss of humus in the 0-40 cm layer of soil by 0.80% in relation to the initial was the impact of surface treatment with annual discing BDT-2,5 (heavy disc harrows) on 10-12 cm or an average annual loss of 1.33 t / ha.

Uzun Süreli Korumalı ve Geleneksel Toprak İşleme Sistemlerinin Beta Glikosidaz Enzim Aktivitesi ve Potansiyel Mineralize Olabilir Azot Üzerine Etkisi

Bu çalışmada, dokuz yıl süre ile uygulanan iki geleneksel, üç azaltılmış ve sıfır toprak işleme yöntemlerinin GEA ve PMN üzerine etkileri belirlenmiş ve karşılaştırılmıştır. Tesadüf blokları şeklinde 2006 yılında başlatılan çalışmada, 6 farklı toprak işleme sistemi için 3 tekerrürlü ve toplam 18 adet parsel yer almaktadır. Bunlara ilaveten, Araştırma alanında, anızlı geleneksel toprak işleme (Gİ–1), anızları yakılmış geleneksel toprak işleme (Gİ–2), ağır diskli tırmıklı azaltılmış toprak işleme (ATİ–1), rototillerli azaltılmış toprak işleme (ATİ–2), ağır diskli tırmıklı azaltılmış sıfır toprak işleme (ASTİ) ve doğrudan ekimli sıfır toprak işleme (STİ) şeklinde altı farklı toprak işleme yöntemi uygulanmaktadır. Ürün rotasyonu olarak bugüne kadar kışlık bitki olarak her yıl buğday ve yazlık olarak (ikinci ürün) buğday hasadını takiben sırasıyla bir yıl mısır ve bir yıl soya yetiştirilmiştir. Toprak işleme sistemlerinin farklılaşması GEA ve PMN konsantrasyonunun önemli düzeyde farklılaşmasına neden olmuştur. Toprak işleme yoğunluğunun azalması ile birlikte önemli düzeyde artış gösteren GEA konsantrasyonu 44,68 mg PNP kg-1 sa-1 (Gİ-2) ile 207,66 mg PNP kg-1 sa-1 (STİ) arasında değişmiştir. Ancak GEA‘da belirlenen trend PMN‘de tespit edilememiştir. Sıfır toprak işleme altındaki topraklarda PMN konsantrasyonu önemli düzeyde yüksek olmakla birlikte ATİ-1 ile PMN konsantrasyonu bakımından aynı grupta yer almıştır. İşlenmemiş topraklarda PMN konsantrasyonunun daha yüksek olmasının muhtemelen toprak strüktürünün parçalanmaması ile ilişkili olduğu düşünülmektedir. Araştırma sonuçları, azaltılmış ve sıfır toprak işleme sistemlerinin bölgede toprağın kalitesinin arttırılması adına son derece gerekli olduğunu ortaya koymaktadır.

Advanced disk-forging process in producing heavy defect-free disk using counteracting dies

During the conventional disk-forging, the upper die repeatedly compresses materials on the flat stationary base. As the strain distributions of the forged disk are non-uniform owing to friction and uneven temperature distribution, more uniform deformation within the entire volume is desirable to obtain sound disk free from defects. This study proposes an advanced disk-forging process in the production of a defect-free heavy disk using counteracting dies. An industry-applicable disk-manufacturing process using a conventional single die-forging process and a proposed counteracting die were characterized and compared based on variations in geometries with successive forging steps. Variations in stress, equivalent strain, and temperature were obtained through three-dimensional finite element simulations using FORGE™ software, during the disk-forging processes of cylindrical preforms. Comparison of the simulation results indicated that the proposed forging process using counteracting dies was highly effective in producing sound disks having uniform microstructure without process-induced defects. The shop-floor production was performed to validate the proposed process, and the feasibility of the process was demonstrated based on the forged disk qualities that were assessed by non-destructive examination and mechanical testing. The test data showed that the defect-free disk with uniform mechanical properties was successfully produced through the proposed forging process using counteracting dies.

Soil compaction on traffic lane due to soil tillage and sugarcane mechanical harvesting operations

Mechanical sugarcane harvesting increases soil compaction due to the intense traffic of agricultural machinery, reducing longevity of sugarcane crops. In order to mitigate the harmful effects caused by agricultural traffic on the soil structure in sugarcane fields, this study evaluated impacts of mechanical sugarcane harvesting on traffic lane under two soil tillage systems based on load bearing capacity models. The experiment was carried out in the region of Piracicaba, state of Sao Paulo, Brazil, on a Rhodic Nitisol, under conventional tillage (CT) and deep strip-tillage (DST). For CT soil tillage was applied to the entire area with a heavy disk harrow, at operating depths from 0.20 to 0.30 m followed by a leveling harrow at a depth of 0.15 m. For DST, soil tillage was performed in part of the area at a depth of 0.80 m, forming strip beds for sugarcane planting, while the traffic lanes were not disturbed. Undisturbed soil samples from traffic lanes were used in the uniaxial compression test to quantify preconsolidation pressure and to model the soil load bearing capacity. The surface layer (0.00-0.10 m) was most susceptible to compaction, regardless of the tillage system (CT or DST) used. In the DST, the traffic lane maintained the previous soil stress history and presented higher load bearing capacity (LBC) than the traffic lane in the CT. As in CT the soil was tilled, the stress history was discontinued. This larger LBC in DTS minimized the impacts of the sugarcane harvest. Under CT, additional soil compaction due to mechanical sugarcane harvesting in the traffic lane was observed after the second sugarcane harvest. There was a reduction in load bearing capacity from 165 kPa to 68 kPa under CT and from 230 kPa to 108 kPa under DST, from the first to the second harvest at surface layer. Water content at mechanical harvesting was the most relevant factor to maximize impacts on the soil structure in traffic lanes, for both tillage systems.

On the directional wave propagation in the tetrachiral and hexachiral lattices with local resonators

The wave propagation in the tetrachiral and hexachiral lattices with local resonators are investigated and the wave behaviors with different geometrical parameters are analyzed. In this study, the tetrachiral and hexachiral lattices are assembled with the repeat unit cells and the unit cell contains a ring and a number of massless slender elastic ligaments. The ligaments are rigidly connected to the ring and the ring contains a heavy disk with its surrounding soft elastic annulus, which acts as the local resonators. The governing equations of the lattices are established by energy variation principle and the wave behaviors of the lattices are calculated by solving the eigenvalue problem with the Bloch’s theorem. The effects of chiral angles on the distributions of band gaps including the width and position are studied to investigate the effects of the chirality and local resonators on the formation of low-frequency band gaps. The first mode of the phase and group velocities are calculated to analyze the effects of the geometrical parameters on the directional frequency-dependent energy flows in the anisotropic structures. We also use the commercial finite element software COMSOL to simulate and verify the directional wave behaviors in the structure. We find that the first mode of the elastic wave spread only along certain specific directions in the tetrachiral structure. As the chiral angle increases, the speed of wave propagation is reduced, and the direction of wave propagation rotates clockwise. The hexachiral lattice exhibits effective isotropic property in the low frequency range, and the wave propagation velocity gradually decreases with the increase of the frequency of the elastic waves.