Surface Ploughing Research Articles

Засоренность посевов и урожайность сои в зависимости от способов обработки почвы, посева и защиты от сорных растений

The primary soil treatment along with herbicide application plays an important role in decreasing weed number in soybean sowings as this crop is differed with slow growth and is not competitive with weeds in the initial phase of development. The purpose of the research is improvement of soybean cultivation tech-nology through increasing of the efficiency of main technological methods (primary soil treatment, sowing method, and chemical ways of weeds control) on leached black soil of the Western Ciscaucasia that will promote high yield of seeds. The research was conducted in 2020–2022. The experiment scheme includes two sowing methods: wide-row (70 cm inter-row spacing) and common row (15 cm interrow spac-ing); three methods of the primary soil treatment: moldboard (25–27 cm), subsurface (25–27 cm), and surface (12–14 cm) ploughing; three herbicide applications in a phase of 1–3 true leaves: Concept, OD (1.0 l/ha), tank mixtures Geyzer, CCS (2.0 l/ha), Tan-to, CCS (0.75 l/ha), Harmony, DFS (7.0 g/ha), Ba-zagran, WS (3.0 l/ha), and Shogun, EC (1.0 l/ha) (standard). The highest weed infestation of soybean sowings was stated in variants with subsurface and surface soil treatments. The application of Concept and the tank mixture of Harmony, Bazagran, and Shogun was very effective – to 87.7% and 88.3%, respectively. The highest yield (2.57–2.68 t/hа) was obtained in variants with subsurface and surface soil treatments in common row sowing at the application of a herbicide Concept and a tank mixture of Har-mony, Bazagran, Shogun.

Correlation development of erosive wear and silt erosion failure mechanisms for pump as turbine

One of the factors contributing to the gradual decline in the performance as well as the failure of hydropower plants over the years is silt erosion. Several researchers have developed empirical correlations for the prediction of erosive wear of hydro turbines, but these correlations are not directly applicable in practice as the materials examined for the impeller blades were different from the actual impeller material. In this study, an effort has been made to experimentally evaluate the silt erosion of the Pump as Turbine (PAT). The novelty of the study is to use the same material (SS304) for the specimens used for the analysis as well as for the impeller. The experiments were performed with three silt sizes of 100–350 μm, 350–700 μm, and 700–1000 μm; with three different silt concentrations of 0.75 %, 1 %, and 1.25 % for the duration of 18 hrs, 36 hrs, and 54 hrs. An empirical correlation is established for the assessment of normalized wear of the PAT impeller in terms of silt size, concentration, and operating time based on the experimental data. This correlation can be utilized to estimate normalized erosive wear of PAT impeller made up of SS304 material with an inaccuracy of ±15 %. According to the analysis, silt concentration was found to be a more significant parameter in causing erosion than silt size. Additionally, scanning electron microscopy was used to conduct a thorough analysis of the erosive failure mechanism of SS304 specimens. According to the analysis, silt size was observed to be an important factor in producing various types of erosive failures. The material removal from the substrate’s surface was found to be caused by plastic deformation and surface ploughing.

Resource-saving technologies for the basic cultivation of chernozem typical in the northeastern region of the Central Chernozem region

The research was carried out with the aim of solving the problem of optimizing the system of basic tillage, providing a reduction in energy costs, obtaining high crop productivity and profitability of production in a grain-fallow crop rotation in the conditions of the northeast of the Central Chernozem Region. The work was carried out in 2013-2021, in a stationary field experiment on a typical heavy loamy chernozem with a high supply of mineral nutrients with a humus content in the arable layer of 6.8-7.0%. The scheme of the experiment included the following options for the main tillage systems: traditional mid-depth moldboard, for soybean at 25-27 cm (control); resource-saving: surface (disking by 10-12 cm) for all crops and non-moldboard mid-depth, 25-27 cm for soybeans and 20-22 cm for cereals; combined: moldboard-less plowing (25% plowing for soybeans + 75% non-moldboard semi-deep plowing for cereals) and moldboard-surface (25% plowing for soybeans + 75% surface plowing for cereals). Against the background of treatments for crop rotation, fertilizers and plant protection products were used. It was found that resource-saving non-moldboard and combined tillage for sowing, on average, for crop rotation crops, accumulated more moisture in the arable layer by 12.1-13.8%, by 3.9-7.8% in the meter layer, compared with traditional moldboard cultivation. . Surface tillage reduced the reserve of productive moisture in the arable layer by 4.4%, in the meter layer - by 5.1%. It has been studied that the best nitrogen, phosphorus and potassium regimes are established with traditional dump and combined dump-surface treatments. In the variants with surface and non-moldboard tillage, a decrease in the content of mineral nutrition elements in the arable soil layer is noted. At the same time, there was an increase in the process of differentiation of the arable layer by fertility with a concentration of nutrients in the layer of 0-10 cm and a significant decrease in them in the layer of 20-30 cm. 2.1 times without herbicides, 2.2 times against the background of herbicide treatment, in terms of the number of weeds and 1.4 and 1.5 times in terms of their mass, in comparison with traditional moldboard treatment. The use of herbicides contributed to a decrease in the number of weeds and the mass of the weed component on average for the variants of the experiment by 55.4 and 60.0%, respectively. It was analyzed that the use of surface and non-moldboard tillage systems led to a decrease in the productivity of a hectare of arable land in crop rotation by 0.09 tons of grain units without protection and by 0.11-0.14 tons in combination with plant protection. The combined (dump-surface) system of tillage ensured the productivity of arable land at the level of the traditional dump system at different depths. It has been proved that the highest profitability of production in crop rotation (250.3%) was achieved using a combined (dump-surface) tillage system in combination with the use of complex protection products (seed dressing + pesticides for crop vegetation). Resource-saving processing systems (surface and non-moldboard) worsened economic performance. Income from the use of these tillage systems decreased by 4.8-5.5%, profitability decreased by 1.6-2.7% compared to the traditional mid-depth moldboard tillage system in crop rotation.

Natural Regeneration of Scots Pine Requires the Application of Silvicultural Treatments such as Overstorey Density Regulation and Soil Preparation

Current management strategies for European Scots pine (Pinus sylvestris L.) forests are oriented towards the use of natural regeneration processes. They aim to maintain continuity of stand structure by preserving seed-producing and shelter trees at varying densities. Soil scarification techniques may be employed to support the natural regeneration of pine. Our study is based on data from seven study sites in the German lowlands, where the basal areas of the overstorey pine trees varied between 4 and 21 m2/ha. The soil scarification methods ranged from full surface ploughing by tractor or horse through small-scale scarification by cultivators to sites without soil scarification. Differences in the densities, spatial distributions, age structures, and above-ground development of pine seedlings were evaluated. We analysed the spatial interactions between overstorey pine trees and the densities of naturally regenerated pine seedlings as a function of the microsite types using the multitype Strauss hard-core process (MSH) method. The results show a significant decrease in height growth with increasing stand density after a period of 5 years, with seedling density and spatial patterns strongly influenced by soil scarification. The MSH pairwise interaction analyses revealed significant negative effects on seedling densities based on combinations of microsites and overstorey trees.

Influence of tillage and fertilizer systems on productive moisture reserves under agrophytocenosis in crop rotation

The paper reveals the results of research on the impact of tillage and fertilizer systems using by-products on moisture reserves in the soil and crop yields in a four-course short-term crop rotation (winter rape – winter wheat – corn for grain – spring barley) on dark gray podzolized soil on the stationary experimental plot of the Institute of Agriculture of Western Polissia NAAS of Ukraine in 2016–2020. Three variants of tillage systems were studied: 1) 20– 22 cm depth moldboard ploughing – control; 2) 10–12 cm depth shallow ploughing; 3) 6–8 cm depth surface ploughing. The system of fertilization involved application of mineral fertilizers N128P90K120 kg/ha of crop rotation area, including the following options for straw: 1) without straw; 2) straw + destructor + N10 kg (ammonium nitrate) per 1 ton of precrop straw; 3) straw + N10 (ammonium nitrate) per 1 ton of pre-crop straw. It has been found out that the reserves of productive moisture in the meter layer of soil on average over the years of research within the period of germination and harvesting (corn, spring barley, winter wheat) in non-moldboard cultivation systems increased by 177.8, 147.1, 99.4 and 74.7, 65.9, 85.4 mm respectively compared with the moldboard ploughing system where moisture reserves were 150.8, 132.8, 73.5 and 55.5, 48.6, 52.6 mm. Under the system of fertilization which provided for the application of straw + N10 and straw + destructor + N10 kg, the reserves of productive moisture in the meter layer were 3.6 and 9.0 mm in the germination period and 10.2 and 14.4 mm in the harvesting period bigger than in the experiment without using straw. The 20–22 cm moldboard ploughing and the 10–12 cm shallow ploughing tillage systems provided higher crop yields compared to the 6–8 cm surface tillage system, which made it possible to obtain 6.91 and 6.50 of winter wheat yields, respectively, 5.37 and 5.13 of spring barley, 11.47 and 11.74 of corn and 3.08 and 3.19 t/ha of winter rape. Resulting from the application of surface tillage system by depth of 6–8 cm, the yield of winter wheat decreased by 1.45, that of spring barley by 1.69, corn by 3.66 and winter rape by 0.31 t/ha. Fertilizer systems based on the use of straw and straw + destructor provided an increase in grain yield respectively: winter wheat by 0.45–0.36 t/ha; corn by 0.60–0.46 t/ha; spring barley by 0.32–0.22 t/ha compared to the option without straw. Key words: productive moisture, crop, straw, tillage, crop rotation, yield.

The Effect of Some Nitrogen Fertilization Practices and Tillage Systems on Growth and Yield of Wheat Crop within The Conditions of The Sedimentary Plain in Iraq

This study was carried out in the Faculty of Agriculture in Abu Ghraib in silty loam texture soil classified as Typic Torrifluvents, as a factorial experiment in split-split plot designs with four replicates. Tillage treatment input in the main blocks, By dividing the field into three sections, the first was left without a tillage (T0), the second was plowed a surface plowing to a depth of 12 cm (T1), while the last section of the field plowed with moldboard plow was used at operating depth of 25 cm (T2). The Nitrogen fertilization was added as the following: Ground addition (N1) included the addition of 125 Kg N ha-1 in two batches were added, first at the second irrigation after germination the wheat crop Ibaa 99 variety (broadcasting) and the second batch at the stage of expulsion of spikes, while the second treatment (N2) was foliar applied on the plant with the same amount above, as well as the third treatment (untreated control) no-Nitrogen fertilizer added (N0).At the end of the experiment after harvesting the following characteristics were studied: plant length, number of strokes, vegetative system weight, grain yield, weight of 1000 grains. Soil bulk density and the Mean weighted diameter of soil aggregate’s for depths of 5-0, 10-5, 20-10, 30-20, and 30-40cm, and we measured the mean weighted diameter and volumetric distribution of soil aggregates by dry sieving method, also the water infiltration.The results showed that the tillage method had significant effect on the soil bulk density values of the soil after preparing the land for cultivation. Also, there were significant differences between tillage treatments in this property values after harvesting. While there was a significant effect of nitrogen fertilization in increasing the soil mean weighted diameter values as affected by tillage when compared with the control treatment (without nitrogen addition), the Nitrogen fertilization resulted a significant increase in the studied wheat crop growth indicators in both tillage treatments T1 and T2. Within two the Nitrogen addition methods N1 and N2 compared to the control treatment for both treatments. In addition, there was a significant effect for interaction for the two studied treatments on the overlap of both factors in the studied growth indicators. Also Nitrogen fertilization had a significant effect on wheat yield content (seed yield, 1000 grain weight and protein content in grains) due to reduce tillage and nitrogen fertilization was reflected in the increase of yield.

Investigation on Tribological and mechanical behaviour of AA6082—Graphene based composites with Ti particles

In the recent years, high strength and low weight materials are being preferred in automobile sectors for fabricating high-speed rotating shafts and machineries. For satisfying dynamic requirements, Aluminium Metal Matrix Composites can be used. In this paper, an attempt has been made to fabricate AA 6082—graphene based Aluminium Matrix Composites reinforced with Titanium (Ti) particles. The effect of increase weight percentage of Graphene and Ti reinforcement on the mechanical characteristics was evaluated. Using tensile tests and surface micro hardness measurements, the fluctuations in mechanical aspects were measured. Tribological characteristics of the Aluminium Matrix Composites were found using pin on disc tribo wear meter, using Silver (Ag) nanoparticles incorporated Jatropha oil as bio-lubricant. Microstructural variations were evaluated by using FESEM which indicated surface tear offs, surface ploughing, demarcations, micro pits, grooves, demarcations, micro cuts and micro tears on the surfaces. The effect of Ag Nano particle addition on Jatropha oil was observed with the fluctuations in Coefficient of friction, specific wear rate and wear mass loss. On increase in reinforcement percentage of G and Ti, specific wear rate was found to decrease and coefficient of friction decreased till 3% by weight reinforcement and beyond 3%, it increased. The surface chemistry modifications were identified using XRD. It was observed that AA6082 Aluminium Matrix Composites reinforced with 3% G and 3% Ti exhibited better mechanical and tribological properties when used with 1% Ag Nanoparticles incorporated Jatropha oil as lubricant.

Sand–concrete interface response: The role of surface texture and confinement conditions

Sand–concrete interface direct shear tests were used to investigate the effects of surface roughness, surface waviness, mean sand diameter and relative density on interface strength and behavior under different confinement conditions. Extreme concrete surface textures, including smooth, rough and rough–wavy textures, were reproduced. Surface plowing was assessed via image analysis, laser scanning and extended multifocal micrographs. The experimental results showed that smooth concrete surfaces exhibited high values of interfacial–to–internal friction angle ratios, ranging 88–90%, due to the angular shape of sand particles. The rough concrete surfaces generated higher interface strength than smooth concrete surfaces; however, the interface strength was still inferior to the surrounding sand strength. Surface plowing, which identified a mixed shear plane at the sand–concrete interface, was developed as particles were detached from the surface, thus inhibiting the interface friction angle from reaching the sand friction angle. Higher sand–concrete interface strength was achieved as surface waviness increased, and interface friction angles greater than the surrounding sand friction angle were reached. Under a constant normal stiffness condition, significantly high interface strength is achieved due to the increase of the current normal stress, which was directly influenced by the initial normal stress, stiffness, surface roughness, mean sand diameter and relative density; surface waviness did not have a marked effect on the normal stress variation. Based on these results, multiple regressions were proposed to estimate the sand–concrete interface strength by the interfacial–to–internal friction angle ratio and the effect of the constant normal stiffness condition.

Estimation of the spatial distribution of spring barley yield using ground-based and satellite spectrophotometric data

The article presents a method for estimating the spatial distribution of spring barley yield, based on the use of optical ground and satellite spectral data (PlanetScope data with a spatial resolution of 3 meters). This approach is highly relevant for the development of precision agriculture technologies. Yield mapping is carried out on the basis of data on the spatial distribution of the actual yield and the spatial distribution of the spectral optical characteristics. The method’s characteristic feature is the use of the integral values of vegetation indices (NDVI, MSAVI2, ClGreen) at various stages of crop development. The method was tested on the basis of stationary field experience, where traditional agriculture (deep plowing) is compared with resource-saving technologies (subsurface and surface plowing, and direct seeding with zero tillage).

Tribological behavior of a hydrostatically extruded ultra-fine grained Ti-13Nb-13Zr alloy

Abstract This contribution summarizes the results an investigation of the wear resistance of as received initial state and nano-structured Ti-13Nb-13Zr alloy obtained by hydrostatic extrusion. The tribological behavior was examined using a ball-on-disc tribometer under unlubricated sliding contact conditions against an Al2O3 ceramic ball. Friction coefficient, material transfer and wear debris of the samples were observed after the wear tests. Wear characteristics of the samples were investigated by means of an optical profilometer, mechanical profilometer and scanning electron microscope for wear debris morphology and wear tracks. Although friction coefficients are very similar according to tribological observations, the domestic distribution of wear characteristics varied for samples of various grain sizes. Morphological observations have shown that surface responses to abrasive ceramic balls involve localized long and short wear debris, fracture, surface plowing causing adhesive wear and the formation of larger surface debris, and material transfer between titanium and the ceramic counterpart.

The evolution of theoretical and practical basis of proceeding from beard tillage to beardless tillage and from surface tillage to no-tillage of Ukrainian soils since the middle of the first part of the 20th century up today

The evolution of theoretical and practical basis of proceeding from beard tillage to beardless tillage and from surface tillage to no-tillage of Ukrainian soils since the middle of the first part of the 20th century up today

Effect of different lubricants on microstructural and tribological properties of TC21 titanium alloy against Si3N4 under fretting–reciprocating sliding

The tribological properties of a Si3N4 ball sliding against a TC21 disc lubricated by pentaerythritol ester (5750), bis (2-ethylhexyl) sebacate (1088), 1-butyl-3-methylimidazolium tetrafluoroborate (L-B104) and an as-synthesized ionic liquid L-C8F17SO3P4444(L-4P) have been studied by an Optimol SRV-V oscillating reciprocating friction and wear with load, temperature and frequency. Scanning electron microscopy and X-ray photoelectron spectroscopy results showed that L-4P has an excellent extreme pressure wear resistant effect (750N) and the lowest friction coefficient (<0.08), in addition to possess excellent tribological behavior due to the formation of chemical reaction (SnF2 and a friction oxidation product lubrication film) and deposition films on the rubbing surface. The wear mechanisms were mainly adhesive wear, abrasive wear and microcosmic fatigue wear, with less cracks on the worn surface. Under the 5750, 1088 and L-B104 lubrications conditions, the friction coefficients were markedly increased with the load increasing and the values were larger, friction surface was a clear plowing effect. The wear mechanisms were mainly surface plowing and abrasive wear. In this investigation, the results demonstrated that L-4P could react with the TC21 titanium alloy to produce lubrication film to improve the tribological properties.

Comparative study of surface integrity aspects of Incoloy 825 during machining with uncoated and CVD multilayer coated inserts

One of the major concerns related to machining of Ni-based super alloy is surface integrity since it directly affects the performance of the machined component during its intended application. In the current study, the influence of cutting speed (51, 84 and 124m/min) and CVD multilayer tool coating (TiN/TiCN/Al2O3/ZrCN) on various aspects of surface integrity such as surface roughness, crystal structure and microstructure of the surface and sub-surface region, thickness of white layer and work hardening tendency have been investigated during dry turning of Incoloy 825. Particular emphasis has been given to understand the mechanism of formation of modified surface layer and the associated process of dynamic recrystallization. The study indicated coated tool resulted in better surface finish compared to that obtained with uncoated tool only at high cutting speed. Various macro features of machined surface included feed mark, material smearing, surface ploughing, re-deposited materials and chip debris. Transformation of crystallographic phase of the machined surface could not be detected compared to that of bulk material. Increase in cutting speed caused gradual refinement of grains, and increased white layer thickness. Coated tool, on the other hand, resulted in the generation of large number of nucleation sites and consequently finer grains at high cutting speed, whereas the uncoated tool promoted growth of sharply defined recrystallized grains. The coated tool prevented the formation of white layer at low and medium cutting speed and also decreased work hardening tendency of Incoloy 825 when compared with that of uncoated tool.

Different tribological behaviors of titanium alloys modified by thermal oxidation and spraying diamond like carbon

The tribological behaviors of titanium alloys modified by new thermal oxidation and spraying diamond like carbon (DLC) were compared with original sample. The structural characteristics, micro-hardness, friction and wear properties in dry fiction and bovine serum lubrication were investigated. According to the results, rutile TiO2 as well as alumina and DLC coating formed with the micro-hardness increasing by 1.27 and 2.21 times separately after being treated by thermal oxidation and spraying DLC, respectively. After modification, the average friction coefficients with a counterface of ZrO2 ball decreased significantly, especially under spraying DLC treatment. After wear test, the wear volumes in dry sliding condition decreased by 37.6% under thermal oxidation and decreased by 94.8% under spraying DLC treatment, respectively. In 25% bovine serum lubrication and compared with the original sample, wear volumes decreased by 70.7% under thermal oxidation and decreased by 93.8% under spraying DLC treatment, respectively. The surface ploughing by the hard mating ball mainly affected the friction and wear of untreated samples. The predominant factor for oxidized samples was the mechanical interaction between two hard ceramic surfaces: (TiO2/Al2O3) and ZrO2 while the improvement of friction and wear resistance for DLC coating was attributed to the decrease of the shearing forces. In this investigation, the results proved that spraying DLC was more promising than thermal oxidation to improve the tribological properties.

Wear Performance of Fly Ash-enhanced Aramid Fibre Reinforced Polymer Matrix Composites

The abrasive wear performance of fly ash filled aramid fibre reinforced phenolic based composites has been investigated on a rubber wheel abrasive wear tester (RWAT). The design of the experiment approach which uses Taguchi’s orthogonal arrays is adopted to objectively evaluate and prioritize five influencing factors that are taken as experimental variables. A predictive mathematical model for damage assessment in wear rate is developed and validated by a well designed set of experiments. The study reveals that sliding distance, external abrading particle size and fly ash content show greater influence on the specific wear rate of the composites. An investigation on worn surface morphology with a scanning electron microscope (SEM) has been carried out to understand the plausible wear mechanisms. The study thus carried out has revealed the decisive role of quartz particles and photovoltaic (PV) conditions in terms of their influence not only on the alterations of topographical attributes, but also surface ploughing, micro-pitting and sub-surface damage as the various modes of wear of these composites.

Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger

This paper describes the first use of Hydrology‐Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The investigation showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season, by altering pool basin microtopography, could reduce the pool persistence time to less than the time needed for establishment of mosquito breeding, approximately 7 days. Undertaking soil surface plowing can also reduce pool persistence time by increasing the infiltration rate through an existing pool basin. Reduction of the pool persistence time to less than the rainfall interstorm period increases the frequency of pool drying events, removing habitat for subadult mosquitoes. Both management approaches could potentially be considered within a given context. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control in water‐limited, Sahelian Africa.

Static and dynamic mechanics of the temporomandibular joint: plowing forces, joint load and tissue stress

OBJECTIVES - To determine the combined effects 1) of stress-field aspect ratio and velocity and compressive strain and 2) joint load, on temporomandibular joint (TMJ) disc mechanics. SETTING AND SAMPLE POPULATION - Fifty-two subjects (30 female; 22 male) participated in the TMJ load experiments. MATERIAL AND METHODS - In the absence of human tissue, pig TMJ discs were used to determine the effects of variables 1) on surface plowing forces, and to build a biphasic finite element model (bFEM) to test the effect of human joint loads and 2) on tissue stresses. In the laboratory, discs received a 7.6 N static load via an acrylic indenter before cyclic movement. Data were recorded and analysed using anova. To determine human joint loads, Research Diagnostic Criteria calibrated investigators classified subjects based on signs of disc displacement (DD) and pain (+DD/+pain, n = 18; +DD/-pain, n = 17; -DD/-pain, n = 17). Three-dimensional geometries were produced for each subject and used in a computer model to calculate joint loads. RESULTS - The combined effects of compressive strain, and aspect ratio and velocity of stress-field translation correlated with plowing forces (R(2) = 0.85). +DD/-pain subjects produced 60% higher joint loads (ANOVA, p < 0.05), which increased bFEM-calculated compressive strain and peak total normal stress. CONCLUSIONS - Static and dynamic variables of the stress-field and subject-dependent joint load significantly affect disc mechanics.

Comparative study of friction behaviour of alumina and zirconia ceramics against steel under water lubricated conditions

PurposeThe paper aims to study the friction behaviour of alumina and zirconia against steel DIN‐Ck45K under water lubricated conditions.Design/methodology/approachThe tests were performed with a contact stress of 3.5 MPa and a constant sliding velocity of 0.5 m/s for 5.35 km of sliding distance, using a pin‐on‐disk tribometer.FindingsThe friction coefficient and the energy dissipated in the contact were considered in this comparative study. The zirconia ceramic present less friction coefficient and contact temperature than alumina ceramic. The zirconia present about 70 per cent of the energy dissipated against when compared with the alumina. Abrasive scars of the surface ploughing were observed on every wear track for two pairs in contact.Research limitations/implicationsThis research used only one test condition.Originality/valueThe paper describes the tribological conditions used and a new methodology based on the energy dissipated in the contact is proposed.

Design of Surface Micro-structures for Friction Control in Micro-systems Applications

In this work, the effectiveness of controlling the frictional force at the micro-scale using well structured surface micro-grooves is demonstrated. Such micro-structured surfaces are designed to eliminate wear particles or contaminants from the sliding interface, thereby, minimizing the effect of surface plowing. Also, the surfaces are designed to minimize the effective area of contact, which is found to have a profound effect on the magnitude of the surface force for micro-systems. Experimental evidence of stiction/friction reduction even at high relative humidity by using such micro-structured surfaces are provided in this work. The results of this work can be utilized in optimization of tribological surface design for micro-systems applications.

Mechanistic Understanding of Material Detachment During CMP Processing

AbstractA combined experimental and numerical approach has been devised to understand the abrasion aspects of material removal mechanisms of ductile copper film on silicon wafers during Chemical mechanical planarization. The experimentally observed trends of the deformation patterns and the force profiles from micro and nano-single scratch experiments are used to guide numerical simulation using finite element simulation at the continuum scale and molecular dynamics simulation at the atomistic scale. Such integrated approach has provided several plausible mechanisms for material detachments through a combination of surface plowing and shearing under the abrasive particles. The gained insights can be integrated into mechanismbased models for the material removal rate in these processes as well as addressing possible defect formation.