An In-Depth Exploration of Unconventional Machining Techniques for INCONEL® Alloys.

Build-up-edge (BUE), high-temperature machining and tool wear (TW) are some of the problems associated with difficult-to-machine materials for high-temperature applications, contributing significantly to high-cost manufacturing and poor tool life (TL) management. A detailed review of non-traditional machining processes that ease the machinability of INCONEL®, decrease manufacturing costs and suppress assembly complications is thus of paramount significance. Progress taken within the field of INCONEL® non-conventional processes from 2016 to 2023, the most recent solutions found in the industry, and the prospects from researchers have been analysed and presented. In ensuing research, it was quickly noticeable that some techniques are yet to be intensely exploited. Non-conventional INCONEL® machining processes have characteristics that can effectively increase the mechanical properties of the produced components without tool-workpiece contact, posing significant advantages over traditional manufacturing.

Investigations on the Surface Integrity and Wear Mechanisms of TiAlYN-Coated Tools in Inconel 718 Milling Operations.

Inconel 718 is a Ni superalloy with superior mechanical properties, even at high temperatures. However, due to its high hardness and low thermal conductivity, it is considered a difficult-to-machine material. This material is widely used in applications that require good dimensional stability, making the milling process the most used in machining this alloy. The wear resulting from this process and the quality of the machined surface are still challenging factors when it comes to Inconel 718. TiAlN-based coating has been used on cutting tools with Yttrium as a doping element to improve the process performance. Based on this, this work evaluated the machined surface integrity and wear resistance of cutting tools coated using Physical Vapor Deposition (PVD) HiPIMS with TiAlYN in the end milling of Inconel 718, varying the process parameters such as cutting speed (vc), feed per tooth (fz), and cutting length (Lcut). It was verified that the Lcut is the parameter that exerts the most significant influence since, even at small distances, Inconel 718 already generates high tool wear (TW). Furthermore, the main wear mechanisms were abrasive and adhesive wear, with the development of a built-up edge (BUE) under a125 m/min feed rate (f) and a Lcut = 15 m. Chipping, cracking, and delamination of the coating were also observed, indicating a lack of adhesion between the coating and the substrate, suggesting the need for a good interlayer or the adjustment of the PVD parameters.

Pigeon Pea Intercropped with Tropical Pasture as a Mitigation Strategy for Enteric Methane Emissions of Nellore Steers.

In this study, we evaluate the effects of intercropping pigeon pea (Cajanus cajan (L.) Millsp.) with tropical pastures for feeding Nellore cattle and compared animal performance and enteric CH4 emissions with other pasture-based systems during the dry and rainy seasons of 2021. Thirty-six Nellore steers (with a body weight of 221 ± 7 kg and an age of 15-16 months) were randomly distributed in three treatments with three replicates (in paddocks of 1.5 hectares each): (1) a degraded pasture of Urochloa spp. (DEG); (2) a recovered and fertilized pasture of Urochloa spp. (REC); and (3) pigeon pea intercropped with Urochloa spp. (MIX). Enteric CH4 emissions were estimated using the sulfur hexafluoride (SF6) tracer gas technique, and dry matter intake (DMI) was determined using internal (iNDF) and external (TiO2) markers. Forages were collected by hand plucking after observations of ingestive behavior, and feces was collected after voluntary defecation. The proportion of grass and legume intake was estimated by C stable isotopes, and the forage nutritional quality was determined, while animal performance was monitored monthly, and the stocking rate was adjusted by the "put and take" technique. The results indicated that intercropping pigeon pea with tropical grasses is an interesting strategy for sustainable livestock production based on pastures. The MIX treatment was able to meet the nutritional requirements of the animals, which presented higher performance. In addition, there was a reduction in CH4 emissions up to 70% when expressed per average daily weight gain in comparison to the DEG treatment.

Greenhouse gas balance and mitigation of pasture-based dairy production systems in the Brazilian Atlantic Forest Biome.

Brazilian cattle production is mostly carried out in pastures, and the need to mitigate the livestock's greenhouse gas (GHG) emissions and its environmental footprint has become an important requirement. The adoption of well-suited breeds and the intensification of pasture-based livestock production systems are alternatives to optimize the sector's land use. However, further research on tropical systems is necessary. The objective of this research was to evaluate the effect of Holstein (HO) and Jersey-Holstein (JE x HO) crossbred cows in different levels of pasture intensification (continuous grazing system with low stocking rate-CLS; irrigated rotational grazing system with high stocking rate-RHS), and the interaction between these two factors on GHG mitigation. Twenty-four HO and 24 JE x HO crossbred dairy cows were used to evaluate the effect of two grazing systems on milk production and composition, soil GHG emissions, methane (CH4) emission, and soil carbon accumulation (0-100 cm). These variables were used to calculate carbon balance (CB), GHG emission intensity, the number of trees required to mitigate GHG emission, and the land-saving effect. The number of trees necessary to mitigate GHG emission was calculated, considering the C balance within the farm gate. The mitigation of GHG emissions comes from the annual growth rate and accumulation of C in eucalyptus trees' trunks. The CB of all systems and genotypes presented a deficit in carbon (C); there was no difference for genotypes, but RHS was more deficient than CLS (-4.99 to CLS and -28.72 to RHS ton CO2e..ha-1.year-1). The deficit of C on GHG emission intensity was similar between genotypes and higher for RHS (-0.480 to RHS and -0.299 to CLS kg CO2e..kg FCPCmilk-1). Lower GHG removals (0.14 to CLS higher than 0.02 to RHS kg CO2e..kg FCPCmilk-1) had the greatest influence on the GHG emission intensity of milk production. The deficit number of trees to abatement emissions was higher to HO (-46.06 to HO and -38.37 trees/cow to JE x HO) and to RHS (-51.9 to RHS and -33.05 trees/cow to CLS). However, when the results are expressed per ton of FCPCmilk, there was a difference only between pasture management, requiring -6.34 tree. ton FCPCmilk-1 for the RHS and -3.99 tree. ton FCPCmilk-1 for the CLS system. The intensification of pastures resulted in higher milk production and land-saving effect of 2.7 ha. Due to the reservation of the pasture-based dairy systems in increasing soil C sequestration to offset the GHG emissions, especially enteric CH4, planting trees can be used as a mitigation strategy. Also, the land-save effect of intensification can contribute to the issue, since the area spared through the intensification in pasture management becomes available for reforestation with commercial trees.

Economic viability of a crop-livestock integration system / Viabilidade econômica de um sistema de integração lavoura-pecuária

ABSTRACT: Crop monoculture and single conventional cattle raising were designed for a rapid increase in productivity and food supply. However, some of these production systems have shown signs of saturation and negative environmental impacts. Crop-livestock integration systems have been developed as an alternative that delivers increased productivity and greater environmental sustainability. This article presents an evaluation of the economic viability and the financial risk associated with an investment in crop-livestock integration with a focus on the production of beef cattle in São Carlos, SP, Brazil. Results showed that the investment is economically viable and has an Internal Rate of Return higher than that of a conventional system. Monte Carlo simulations showed that the integrated system presents lower market risks when compared to the conventional system.

RESUMO: A produção agrícola em monocultivo e a pecuária convencional não integrada com culturas foram desenhadas para um aumento rápido da produtividade e da oferta de alimentos. Entretanto, alguns destes sistemas de produção têm mostrado sinais de saturação e impactos ambientais negativos. Sistemas de integração lavoura-pecuária têm sido desenvolvidos como uma alternativa que oferece aumento de produtividade e maior sustentabilidade ambiental. O presente trabalho tem por objetivo estimar a viabilidade econômica e o risco financeiro associado a um projeto de investimento em integração lavoura-pecuária com foco para a produção de animais de corte em São Carlos, SP. Os resultados mostraram que o investimento é economicamente viável e apresenta Taxa Interna de Retorno superior à de um sistema convencional. Por meio da simulação de Monte Carlo constatou-se o sistema integrado apresenta menores riscos de mercado quando comparado com o sistema convencional.

Pasture intensification in beef cattle production can affect methane emission intensity.

Increasing greenhouse gas (GHG) emissions from anthropogenic activities have contributed to global warming and consequently to climate change. Among all sources of emissions, the agricultural sector accounts for just under a quarter, mainly because of the intensification of food production systems necessary to supply the growing demand of the population. As ruminal fermentation is the largest source of methane emission in the livestock industry, emission by cattle has become the focus of studies. The aim of this study was to evaluate enteric methane emission and emission intensities of Nellore cattle at different ages submitted to levels of intensification of the grazing system. Twenty-four animals per cycle (age of 21.8 and 13.1 mo in cycles 1 and 2, respectively) were randomly distributed across different grazing systems: irrigated pasture with a high stocking rate (IHS), dryland pasture with a high stocking rate (DHS), recovering dryland pasture with a moderate stocking rate (DMS), and degraded pasture with a low stocking rate (DP). Methane emission was measured using the sulfur hexafluoride technique in each season of the cycle. Intensive systems provided higher yields of good-quality forage as well as superior animal performance when compared with DP. Methane yields were different between seasons and cycles. Methane emissions per average daily weight gain and dry matter digestible intake were different between treatments. Differences in the results were observed when they were analyzed per hectare, with the highest gain yield (P = 0.0134), stocking rate, weight gain, carcass production, and total methane emission (P < 0.0001) being found for the intensive systems. There were no differences in emissions per weight gain or carcass production between production systems, while a difference was observed between cycles (P = 0.0189 and P = 0.0255, respectively), resulting in lower emission intensities for younger animals. We conclude that more intensive systems resulted in a higher kilograms production of carcass per hectare; however, animals at 19 mo of age raised in the IHS and DMS systems had a lower emission intensity in kilogram of CO2-eq. per kilogram of carcass. Moderate intensification (DMS) using animals at about 19 mo of age might be an effective strategy to mitigate GHG emissions from Brazilian tropical pastures. Further studies are needed to understand the relationship between increasing productivity and decreasing environmental impacts, especially methane emission from ruminants.

Methane Emissions, Performance and Carcass Characteristics of Different Lines of Beef Steers Reared on Pasture and Finished in Feedlot.

The present study aimed to investigate whether different lines of a composite breed (5/8 Charolais × 3/8 Zebu), formed at different times, and genetically improved, would result in differences in animal performance, enteric methane emissions, and carcass traits. Forty-six Canchim steers (15 months, 280 ± 33 kg liveweight) from three different lines were used: old, new, and their cross. These three breed lines were considered the treatments (arranged in four randomized blocks based on initial liveweight) and were evaluated under grazing and feedlot conditions in relation to the performance and emission of enteric methane. During the grazing period, the new line was found to be superior to the old only in relation to the average daily liveweight gain (0.692 vs. 0.547 kg/day), and with no differences in relation to the cross line (0.692 vs. 0.620). In the feedlot finishing phase, only the average daily liveweight gain was significantly higher in the new line compared to the cross and old line (1.44 vs. 1.32 and 1.23 kg/day). The new and cross lines demonstrated higher dry matter intake when compared to the old line (10.25 and 10.42 vs. 9.11 kg/day), with the crossline animals demonstrating the best feed conversion. The new line showed higher enteric methane emissions compared to the old line (178 vs. 156 g/day). The line had an effect on the carcass dressing of the animals, with greater fat thickness in carcasses from the new and cross lines than the old line (4.4 and 3.8 vs. 3.2 mm). Canchim cattle selected for improved productive performance characteristics does not guarantee animals with lower methane emissions under grazing conditions; while in feedlots, can lead to increased daily feed consumption, and hence, to higher emissions of methane.

Behavior and body surface temperature of beef cattle in integrated crop-livestock systems with or without tree shading.

Pasture-based livestock production is largely centered on monoculture systems that degrade grasslands. In integrated crop-livestock-forestry systems a synergy is supposed to occur between its components, contributing to global food production. Thus, this study aimed to evaluate the effects of the microclimate on integrated crop-livestock-forestry (CLF) and crop-livestock (CL) systems on the behavior and body surface temperatures of beef cattle in a tropical climate. The experiment was carried from December/2016 to June/2017. Adult beef cows were maintained in CL (n = 11) or CLF (n = 12) systems, permanently monitored by automatic weather stations. The microclimatic conditions indicated that CLF was more effective in mitigating the environmental heat load. Animals maintained in CLF showed favorable behavior, longer rumination (42.9 ±â€¯2.2 vs 36.6 ±â€¯2.2 min) and shorter resting time (57.6 ±â€¯2.7 vs 65.9 ±â€¯2.8 min) during the morning. The grazing time and other activities did not differ between treatments (P > 0.05) in the afternoon. Animals in CLF exhibited lower surface temperatures of the back (TBack: 31.9 ±â€¯0.2 vs 32.8 ±â€¯0.2 °C, P < 0.05) and of the trunk (TTrunk: 32.0 ±â€¯0.1 vs 32.5 ±â€¯0.1 °C, P < 0.05) measured by infrared thermography. Animals maintained in CLF showed a significant preferential use of shade and a 23% reduction in the frequency of the animals searching for water troughs. It is evident from the study that integrated crop-livestock-forestry systems can be used to provide a more favorable microclimate within grasslands. Thus, beef cattle benefits from the milder environment and exhibits a higher thermal comfort, which favors food production and the rational use of natural resources.

Epworth sleepiness scale outcome in 616 Brazilian medical students

The Epworth Sleepiness Scale (ESS) measures daytime sleepiness in adults. This paper reports the following data in 616 medical students: 1-ESS scores, 2-its correlation with the declared night sleep time, 3-comparison with ESS values obtained from Australia, 4-comparison of ESS values in a sub-population of 111 students tested early and late 1995. There were 387 males, 185 females and 4 not specified. Age = 20.16+2.23 (SD). ESS score = 10.00+3.69 (SD), declared sleep time = 7.04+1.033 (SD). ESS scores did not sttistically correlate with sleep time. Average ESS score was statistically higher than in the Australian sample. Retesting of the medical students showed an increase in ESS values from March to November 1995. Sleep time difference was non-significant. Higher ESS scores in this sample seem to be related to shorter sleep time, but fatigue effects can not be ruled out.

Resultados da escala de sonolencia Epworth em 480 alunos de graduacao da Faculdade de Medicina da Universidade de Sao Paulo / Epworth sleepiness scale outcome in 480 Brazilian medical students

Este estudo relata os resultados da aplicacao da Escala de Sonolencia de Epworth (ESE) em 480 alunos da FMUSP, o resultado da correlacao do valor obtido da ESE com o numero declarado de horas de sono por noite e a comparacao com um estudo semelhante com alunos de medicina da Australia. A ESE e um questionario auto-aplicado de 8 itens usado para se avaliar sonolencia subjetiva em adultos. Os valores da ESE variam de 0 ate o maximo de 24 pontos. Os questionarios foram aplicados no final de 1994. Total de respostas = 480 sendo que 293 masculino, 185 feminino. Idade media = 20,55 + ou - 2,15 (DP). Etnia branca = 3346; amarela = 96; negra = 3; outros = 10; nao declarados = 25...