Association between Agricultural Production Value and the Use of Rural Area within the Municipalities in the State of Sao Paulo, Brazil

Rural economic development can differ intensely among municipalities within the same region. The economic activity disparity among them makes public policy actions difficult. It is possible to find highly efficient and globally competitive producers, as well as those producing for subsistence, in the same area. This disparity stands out the total productivity importance of the factors of production in the agricultural sector, especially the productivity of the land. The way the land is occupied in the rural area, namely crops, pastures, reforestation and other areas, can be indicative of the productivity of the land factor and the value of agricultural production. The products that compose the value of the agricultural production present different land occupation through their own productive characteristic. The main objective of this work was to measure the association between the production value of groups of agricultural products and the diversified uses of the rural area in the production of the municipalities in the state of Sao Paulo. In this research, 52 agricultural products produced in 2008 were used, grouped in five production value variables and other nine variables of the land use in production of the municipalities in Sao Paulo. The multivariate statistical technique of canonical correlation was used to measure the association between the product variables group of the production value with the land use group in agricultural activities. It was concluded that there is a strong correlation （94.3%） in the first pair of canonical variables, representing the production value and the land use, allowing groups of municipalities to be formed at different stages of development in agricultural production. It can be verified that 61.8% of the municipalities in the state were below the average in the production group and land use and that only 4.8% were above average for the production variables group and with values below the average in land use. The stages of agricultural development in the municipalities of Sao Paulo and the association between the production and use of the area can contribute to identify the direction of public policies to increase the productivity of the agricultural sector.

Comparison of iron aluminide Fe_(3)Al with armour steel in ballistic behaviour OA

Intermetallic aluminide compounds possess several potential advantages compared to alloyed steels,like enhanced oxidation resistance,lower density and the omittance of critical raw materials.Iron aluminides,compared to other transition metal-aluminides of TM_(3)-Al type,although having a higher density compared to titan-aluminides,have a lower density compared to nickel-aluminides,but also a higher ductility than both alternatives,making this material potentially effective in ballistic protection application.Density-wise,this material may be a worthy alternative to armour steels,which was the aim of this study.Two materials,Fe_(3)Al intermetallic compound(F3A-C)and Armox 500 armour steel were ballistically tested against tungsten-carbide(WC)armour-piercing ammunition,in accordance with STANAG 4569.After ballistic testing,microhardness and metallographic testing were performed,revealing differences in strain hardening,crack propagation mode and exit hole morphology.F3A-C ballistic resistance is similar to that of armour steel,in spite of the lower tensile and impact mechanical properties,relying on a considerably higher strain hardening rate,thermal properties and a lower density.

A Review and Bibliometric Analysis of the Current Studies for the 6G Networks

The race to develop the next generation of wireless networks,known as Sixth Generation(6G)wireless,which will be operational in 2030,has already begun.To realize its full potential over the next decade,6G will undoubtedly necessitate additional improvements that integrate existing solutions with cutting-edge ones.However,the studies about 6G are mainly limited and scattered,whereas no bibliometric study covers the 6G field.Thus,this study aims to review,examine,and summarize existing studies and research activities in 6G.This study has examined the Scopus database through a bibliometric analysis of more than 1,000 papers published between 2017 and 2021.Then,we applied the bibliometric analysis methods by including(1)document type,(2)subject area,(3)author,and(4)country of publication.The study’s results reflect the research 6G community’s trends,highlight important research challenges,and elucidate potential directions for future research in this interesting area.

A new electric field mill array with each of the mill’s rotor controlled precisely by a GPS module:Equipment and initial results

We have newly designed an electrostatic sensor,called an electric field mill(EFM),to simplify the estimation of the charge position and charge amount transferred by lightning discharges.It is necessary for this remote estimation of the transferred charge to measure electric field changes caused by charge loss at the time of a lightning strike at multiple locations.For multiple-station measurement of electric field changes,not only speed but also phase for exposure and shielding of the sensing plates inside each EFM of the array should be synchronized to maintain the sensitivities of the deployed instruments.Currently,there is no such EFM with specified speed and phase control performance of the rotary part.Thus,we developed a new EFM in which the rotary mechanism was controlled consistently to within 3%error by a GPS module.Five EFMs had been distributed in the Hokuriku area of Japan during the winter season of 2022-2023 for a test observation.Here we describe the design and a simple calibration method for our new EFM array.Data analysis method based on the assumption of a simple monopole charge structure is also summarized.For validation,locations of assumed point charges were compared with three-dimensional lightning mapping data estimated by radio observations in the MF-HF bands.Initial results indicated the validity to estimate transferred charge amounts and positions of winter cloud-to-ground lightning discharges with our new EFM array.

Deformation behaviors of magnesium alloy AZ31 sheet in cold deep drawing

To investigate how the popular magnesium alloy AZ31 sheet(aluminum 3%,zinc 1%)behaves in cold working,deep drawing experiments at room temperature,along with finite element(FE)simulation,were performed on the cold forming sheet of the AZ31 alloy after being annealed under various conditions.The activities were focused on the fracture pattern,limit drawing ratio(LDR),deformation load,thickness distribution,anisotropic effect,as well as the influences of the annealing conditions and tool configuration on them.The results display that punch shoulder radius instead of die clearance,has much influence on the thickness distribution.The anisotropy is remarkable in cold working,which adversely impacts the LDR.The fracture often happens on the side wall at an angle to axis of the deformed specimen.The results also imply that the LDR for the material under present experimental conditions is 1.72,and annealing the material at 450 ℃ for 1 h may be preferable for the cold deep drawing.

High temperature tribological behaviors of aluminum matrix composites reinforced with solid lubricant particles

The AA6061-10 wt.%B4 C mono composite, AA6061-10 wt.%B4 C-Gr(Gr: graphite) hybrid composites containing 2.5, 5, and 7.5 wt.% Gr particles, and AA6061-10 wt.%B4 C-Mo S2 hybrid composites containing 2.5, 5, and 7.5 wt.% Mo S2 particles were fabricated through stir casting. The dry sliding tribological behaviors of the mono composite and hybrid composites were studied as a function of temperature on high temperature pin-on-disc tribotester against EN 31 counterface. The wear rate and friction coefficient of the Gr-reinforced and Mo S2-reinforced hybrid composites decreased in the temperature range of 30-100 ℃ due to the combined lubrication offered by the wear protective layer and its solid lubricant phase. Scanning electron microscopy(SEM) observation of the worn pin surface revealed severe adhesion, delamination, and abrasion wear mechanisms at temperatures of 150, 200, and 250 ℃, respectively. At 150 ℃, transmission electron microscopy(TEM) observation of the hybrid composites revealed the formation of deformation bands due to severe plastic deformation and fine crystalline structure due to dynamic recrystallization.

Microstructure and corrosion behavior of NiTi shape memory alloys sintered in the SPS process

NiTi shape memory alloys(SMAs) was developed using the spark-plasma sintering(SPS) process with different average particle size(45 μm and 10 μm) under various temperature. The influence of particle size and temperature on the density, microstructure, and corrosion behavior of the NiTi in simulated body fluid was examined. The porosity decreased with increasing sintering temperature and decreasing particle size, which resulted in an increase in density of the alloy. Increasing the sintering temperature led to the formation of Ni-and Ti-rich intermetallic such as Ni3Ti and NiTi2. The formation of these secondary phases influenced the corrosion behavior of NiTi by changing its chemical composition. The planar structure of NiTi was transformed into a dendritic structure at 900℃, which resulted in the formation of uniform oxide and phosphate layers on the entire surface. A high corrosion potential and low corrosion current density were achieved with NiTi prepared with 10 μm particles at 900℃, which exhibited superior corrosion resistance.

Multiobjective optimization of friction welding of UNS S32205 duplex stainless steel

The present study is to optimize the process parameters for friction welding of duplex stainless steel(DSS UNS S32205).Experiments were conducted according to central composite design.Process variables,as inputs of the neural network,included friction pressure,upsetting pressure,speed and burn-off length.Tensile strength and microhardness were selected as the outputs of the neural networks.The weld metals had higher hardness and tensile strength than the base material due to grain refinement which caused failures away from the joint interface during tensile testing.Due to shorter heating time,no secondary phase intermetallic precipitation was observed in the weld joint.A multi-layer perceptron neural network was established for modeling purpose.Five various training algorithms,belonging to three classes,namely gradient descent,genetic algorithm and LevenbergeM arquardt,were used to train artificial neural network.The optimization was carried out by using particle swarm optimization method.Confirmation test was carried out by setting the optimized parameters.In conformation test,maximum tensile strength and maximum hardness obtained are 822 MPa and 322 Hv,respectively.The metallurgical investigations revealed that base metal,partially deformed zone and weld zone maintain austenite/ferrite proportion of 50:50.

Experimental and numerical analyses of magnesium alloy hot workability

Due to their hexagonal crystal structure,magnesium alloys have relatively low workability at room temperature.In this study,the hot workability behavior of cast-extruded AZ31B magnesium alloy is studied through hot compression testing,numerical modeling and microstructural analyses.Hot deformation tests are performed at temperatures of 250℃ to 400℃ under strain rates of 0.01 to 1.0 s^(−1).Transmission electron microscopy is used to reveal the presence of dynamic recrystallization(DRX),dynamic recovery(DRY),cracks and shear bands.To predict plastic instabilities during hot compression tests of AZ31B magnesium alloy,the authors use Johnson–Cook damage model in a 3D finite element simulation.The optimal hot workability of magnesium alloy is found at a temperature(T)of 400℃ and strain rate(ε)of 0.01 s^(−1).Stability is found at a lower strain rate,and instability is found at a higher strain rate.

Investigation on dry sliding wear behavior of Mg/BN nanocomposites

The present research objective is to investigate the effect of boron nitride nanoparticles reinforcement on dry sliding wear behavior of pure Magnesium and magnesium nanocomposites.The fabricated nanocomposites contains varied percentages of boron nitride such as 0%(pure Mg),0.5%,1.5%and 2.5%were synthesized by using powder metallurgy technique and followed by a hot working process called hot extrusion.The pin on disk equipment was used for conducting the wear tests for traditional loads of 5 N,7 N and 10 N at different sliding speeds of 0.6,0.9 and 1.2 m/s against the steel disk at room temperature.For all traditional loads and sliding speeds,the changes in wear rate and friction co-efficient(μ)with respect to sliding distances were observed and analyzed.The wear characteristics are observed with the help of scanning electron microscopy under given test conditions.To investigate dominant wear mechanisms for various test conditions,the morphologies of all worn composites surfaces were analyzed.Final results show that,for all nanocomposites the wear level raises with respect to the sliding speeds and loads.Magnesium reinforced with 0.5%boron nitride shows lower wear rates and low friction coefficient values compare with magnesium reinforced with 1.5%boron nitride and 2.5%boron nitride nanocomposites.

Effect of thermal cycle on Ni-Cr based nanostructured thermal spray coating in boiler tubes

Ni-Cr based nanostructured feedstock powder was prepared by mechanical milling technique involving repeated welding, fracturing, and re-welding of powder particles in a planetary ball mill. The milled nanocrystalline powders were used to coat carbon steel tubes using high velocity oxygen fuel（HVOF） thermal spraying process. The characterization of the feedstock powder and HVOF coated substrates was performed using optical microscope, X-ray diffractometer（XRD）, scanning electron microscope（SEM）, high resolution transmission electron microscope（HR-TEM）, energy dispersive spectrometer（EDS） and microhardness tests. The coated and uncoated samples were subjected to different thermal cycles and characterized for their phase changes, metallurgical changes and microhardness variations. Ni-Cr nanostructured coated samples exhibited higher mechanical and metallurgical properties compared to their conventionally coated counter parts. The results showed that the nanostructured coating possessed a more uniform and denser microstructure than the conventional coating.

Integrated risk management: a Petrobras application in offshore well construction safety to minimize critical emergency disconnections

In order to avoid mistakes and to save a great deal of time in analysis, an innovative methodology was developed that can analyze the well operations and rig characteristics involved to define the best emergency disconnect sequence （EDS） available. A solution was developed based on the characteristics of the rigs and blowout preventers （BOPs）, and six variables were considered that directly affect the choice of EDS. All possible combinations of 64 scenarios were analyzed, and the priority of choice of the EDS was defined empirically. This paper presents an approach to EDS risk management and examples of exposure time （time without riser safety margin and shear capability） for the same well, which can be lowered from 13% to 0.1%. The impact of this reduction is related to the ability of the BOP to cut some of the heavy casings, in addition to improved availability of EDS modes. This implementation opened up many possibilities for the performance of risk exposure analysis, enabling comparison of several BOP configurations of contracted rigs and selection of the best options. This innovative approach allowed a better management of the rig schedules, prioritizing safety aspects and making it possible to allocate the fleet in a systematic way.

Repair of automotive bumpers and bars with modified friction stir welding

This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used for joining of acrylonitrile butadiene styrene(ABS)composites.The dissimilar thermoplastics were processed for maintaining a useful range of melt flow properties followed by preparation of feed stock filament for fused deposition modeling(FDM)process through screw extrusion.Finally,3D printed PA6 based consumable rapid tool(RT)was prepared for MFSW.The joints prepared were subjected to flexural,hardness,morphological and thermal testing.The study has suggested the that maximum mechanical strength was obtained for sample welded at 1400 r/min,50 mm/min transverse speed and 3 mm plunge depth,whereas the minimum mechanical strength was obtained for sample welded at 1000 r/min,30 mm/min transverse speed and 2 mm plunge depth.The results are also supported with thermal analysis and photomicrographs.

Optimisation of laser welding parameters for welding of P92 material using Taguchi based grey relational analysis

Creep strength enhanced ferritic(CSEF) steels are used in advanced power plant systems for high temperature applications. P92(Cr–W–Mo–V)steel, classified under CSEF steels, is a candidate material for piping, tubing, etc., in ultra-super critical and advanced ultra-super critical boiler applications. In the present work, laser welding process has been optimised for P92 material by using Taguchi based grey relational analysis(GRA).Bead on plate(BOP) trials were carried out using a 3.5 k W diffusion cooled slab CO_2 laser by varying laser power, welding speed and focal position. The optimum parameters have been derived by considering the responses such as depth of penetration, weld width and heat affected zone(HAZ) width. Analysis of variance(ANOVA) has been used to analyse the effect of different parameters on the responses. Based on ANOVA, laser power of 3 k W, welding speed of 1 m/min and focal plane at-4 mm have evolved as optimised set of parameters. The responses of the optimised parameters obtained using the GRA have been verified experimentally and found to closely correlate with the predicted value.? 2016 China Ordnance Society. Production and hosting by Elsevier B.V. All rights reserved.

Sliding wear behaviour of AZ31B magnesium alloy and nano-composite

AZ31B magnesium alloy and nano-composite were manufactured by hybrid casting process and hot extruded at 350 °C. The sliding wear behaviour of alloy and nano-composite was estimated at room temperature using the standard pin-on-disc wear test equipment. The tests were conducted under a normal load of 10 N at different sliding speeds ranging from 0.60 to 1.2 m/s for distance up to 2000 m. The wear mechanisms of the worn out surface were studied using SEM analysis. The influence of test parameters on wear rate of the pins was established using a linear regression model statistically. Compared with the AZ31B magnesium alloy, the nano-composite shows lower wear rates due to higher hardness improvement caused by the reinforcement. The wear mechanism appears to be a mix-up of ploughing, rows of furrows, delamination and oxidation.

FEM Modeling of Crack Propagation in a Model Multiphase Alloy

In this paper, several widely applied fracture criteria were first numerically examined and the crack-tip-region Jntegral criterion was confirmed to be more applicable to predict fracture angle in an elastic-plastic multiphase material. Then, the crack propagation in an idealized an elastic-plastic finite element method. The variation dendritic two-phase AI-7%Si alloy was modeled using of crack growth driving force with crack extension was also demonstrated. It is found that the crack path is significantly influenced by the presence of α-phase near the crack tip, and the crack growth driving force varies drastically from place to place. Lastly, the simulated fracture path in the two-phase model alloy was compared with the experimentally observed fracture path.

Comparative study on transverse shrinkage, mechanical and metallurgical properties of AA2219 aluminium weld joints prepared by gas tungsten arc and gas metal arc welding processes

Aluminium alloy AA2219 is a high strength alloy belonging to 2000 series. It has been widely used for aerospace applications, especially for construction of cryogenic fuel tank. However, arc welding of AA2219 material is very critical. The major problems that arise in arc welding of AA2219 are the adverse development of residual stresses and the re-distribution as well as dissolution of copper rich phase in the weld joint.These effects increase with increase in heat input. Thus, special attention was taken to especially thick section welding of AA2219-T87 aluminium alloy. Hence, the present work describes the 25 mm-thick AA2219-T87 aluminium alloy plate butt welded by GTAW and GMAW processes using multi-pass welding procedure in double V groove design. The transverse shrinkage, conventional mechanical and metallurgical properties of both the locations on weld joints were studied. It is observed that the fair copper rich cellular(CRC) network is on Side-A of both the weldments. Further, it is noticed that, the severity of weld thermal cycle near to the fusion line of HAZ is reduced due to low heat input in GTAW process which results in non dissolution of copper rich phase. Based on the mechanical and metallurgical properties it is inferred that GTAW process is used to improve the aforementioned characteristics of weld joints in comparison to GMAW process.

Optimization of electrical discharge machining process parameters for Al6061/cenosphere composite using grey-based hybrid approach

Fly ash has congregated considerable attention as a potential reinforcement for aluminum matrix composites(AMCs)to enhance selective properties and reduce the cost of fabrication.However,poor machinability of such AMCs limits their application.The present study focuses on the preparation of cenosphere fly ash reinforced Al6061alloys by compo casting method.X-ray diffraction analysis of the prepared AMCs exposes the presence of cenosphere particles without any formation of other intermetallic compounds.In this study,electrical discharge machining(EDM)was engaged to examine the machinability of the prepared metal matrix composite(MMCs).The measured performance characteristics for the various combinations of input process parameters were considered to be MRR,EWR and SR.Face centered central composite design(CCD)of response surface method(RSM)was employed to design the number of experimental trials required and a hybrid approach of grey-based response surface methodology(GRSM)was imposed for predicting the optimal combination of processing parameter in EDM process.Generous improvement was observed in the performance characteristics obtained by employing both the optimal setting of machining parameters.The optical3D surface profile graphs of the ED machined surface also revealed the improvement in surface quality and texture employing the optimal processing conditions proposed by hybrid GRSM approach.

Prediction and Verification of Resistance Spot Welding Results of Ultra-High Strength Steels through FE Simulations

Resistance spot welding (RSW) is the most common welding method in automotive engineering due to its low cost and high ability of automation. However, physical weldability testing is costly, time consuming and dependent of supplies of material and equipment. Finite Element (FE) simulations have been utilized to understand, verify and optimize manufacturing processes more efficiently. The present work aims to verify the capability of FE models for the RSW process by comparing simulation results to physical experiments for materials used in automotive production, with yield strengths from approximately 280 MPa to more than 1500 MPa. Previous research has mainly focused on lower strength materials. The physical weld results were assessed using destructive testing and an analysis of expulsion limits was also carried out. Extensive new determination of material data was carried out. The material data analysis was based on physical testing of material specimens, material simulation and comparison to data from literature. The study showed good agreement between simulations and physical testing. The mean absolute error of weld nugget size was 0.68 mm and the mean absolute error of expulsion limit was 1.10 kA.

Multi criteria decision making through TOPSIS and COPRAS on drilling parameters of magnesium AZ91

Magnesium(Mg)alloys are extensively used in the automotive and aircraft industries due to their prominent properties.The selection of appropriate process parameters is an important decision to be made because of the cost reduction and quality improvement.This decision entails the selection of suitable process parameters concerning various conflicting factors,so it has to be addressed with the Multiple Criteria Decision Making(MCDM)method.Therefore,this work addresses the MCDM problem through the TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)and COPRAS(COmplex PRoportional ASsessment)methods.The assessment carried out in the material Mg AZ91 with the Solid Carbide(SC)drill bit.The dependent parameters like drilling time,burr height,burr thickness,and roughness are considered with the independent parameters like spindle speed and feed rate.Drilling alternatives are ranked using the above said two methods and the results are evaluated.The optimum combination was found on the basis of TOPSIS and COPRAS for simultaneous minimization of all the responses which is found with a spindle speed of 4540 rpm and a feed rate of 0.076 mm/rev.The identical sequencing order was observed in TOPSIS and COPRAS method.The empirical model was developed through Box-Behnken design for each response.Superior empirical model developed for drilling time which is 3.959 times accurate than the conventional equation.The trends of various dependents based on the heterogeneity of various independents are not identical,these complex mechanisms are identified and reported.The optimized results of the Desirability Function Approach are greater accordance with the TOPSIS and COPRAS top rank.The confirmation results are observed with lesser deviation suggesting the selection of the above independent parameters.