Adjuvants alter the physical–chemical properties of pesticide formulations, influencing either the droplet size or drift phenomenon. Selecting the appropriate adjuvant and understanding its characteristics can contribute to the efficiency of Plant Protection Product (PPP) application. This reduces drift losses and promotes better deposition on the crop. The objective of this study was to evaluate the effects of four commercial adjuvants based on mineral oil (Agefix and Assist), vegetable oil (Aureo), and polymer (BREAK-THRU) on the physical–chemical properties (surface tension, contact angle, volumetric mass, electrical conductivity, and pH), droplet size, and drift, using pure water as the control treatment (no adjuvant). Surface tension and contact angle were measured with a DSA30 droplet shape analyzer, while droplet size measurements were determined through a laser diffraction particle analyzer (Malvern Spraytec), using a single flat fan spray nozzle (AXI 110 03) operating at 0.3 MPa. Drift reduction potential was evaluated inside a wind tunnel with an air speed of 2 m s−1. All adjuvants reduced surface tension and contact angle compared to water. volumetric median diameter (VMD) increased for Aureo, Assist, and Agefix, generating coarse, medium, and medium droplets, respectively, while BREAK-THRU formed fine droplets, similar to those generated by water. Aureo had the greatest reduction in Relative Span Factor (RSF), with a reduction of 30.3%. Overall, Aureo, Assist, and Agefix adjuvants significantly reduced the percentage of droplets 500 µm. Drift reduction potential was achieved for all adjuvants, with Aureo showing the highest reduction of 59.35%. The study confirms that selecting the appropriate adjuvant can improve PPP application and promote environmental sustainability in agricultural practices.

Spray droplet diameters play a key role in the field of liquid plant protection product (PPP) application technology. However, the availability of various measurement techniques, each with its unique operating principles for evaluating droplet size spectra, can lead to different interpretations of spray characteristics. Therefore, in this study, four measurement techniques—Liquid Immersion (LI), Laser Diffraction (LD), Phase Doppler Particle Analysis (PDPA), and Shadowgraphy (SG)—were utilized to evaluate the droplet size distribution of agricultural spray nozzles. Additionally, PDPA and SG were used to assess the average velocity of spray droplets. Experiments were conducted in three different laboratories with the main aim of comparing results obtained with various types of equipment utilized under ordinary practical conditions. Spraying tests were carried out using three flat fan nozzles and an air-induction flat fan nozzle. As a general trend, the lowest values for droplet diameters were measured using the Laser Diffraction technique, followed by Shadowgraphy. The PDPA technique provided the highest values for mean diameters (D₁₀, D₂₀, and D₃₀) and the numeric median diameter (Dn_0.5), whereas the Liquid Immersion method yielded the highest values for the Sauter mean diameter (D₃₂) and volumetric diameters (Dv_0.1, Dv_0.5, and Dv_0.9). Importantly, all measurement techniques were able to discriminate the four nozzles based on their Dv_0.5 diameter. Average droplet velocities showed a similar pattern across the four nozzles with the PDPA and the SG measurement techniques. The differences in diameter values observed with the four measurement techniques underline the necessity of always including reference nozzles in spray quality assessments to base classifications on relative rather than absolute values.

The use of agricultural residues in anaerobic digestion (AD) for biogas production promotes environmental and socioeconomic benefits. This study aimed to evaluate the biogas production from dry coffee husks (DCH), wet coffee husks (WCH), and cattle manure (CM) in AD. Prototypes of Indian anaerobic benchtop digesters with a batch feeding system supplied with 100 CM, 100 DCH, and 100 WCH for anaerobic mono-digestion (AMoD) and 25:75 DCH:CM and WCH:CM for anaerobic co-digestion (ACoD) were used in the experiment. The dry husk was mechanically pre-treated with grinding in a manual mill. Moisture and total solid presented no statistically significant difference between the studied relationships but the coffee husk as a co-digestant acidified the medium to be digested. The 25:75 DCH:CM ratio anticipated biogas production (7th week) and showed higher potential for weekly and accumulated biogas production. The Gompertz model showed the best fit considering the coefficient of determination, mean relative error, standard deviation of the estimate, and mean squared deviation. Therefore, the coffee husk as a co-digestant of cattle manure is a potential lignocellulosic biomass for biogas production provided that the process is conducted under pre-treatment.

O sistema integrado entre aquicultura, hidroponia e dejeto bovino apresenta soluções ambientalmente viáveis para produção de alimentos e energia no meio urbano. Os biodigestores anaeróbios são compostos por câmara hermética, na qual sob condições ideais de operação permitem que bactérias degradem os resíduos orgânicos presentes no sistema. O biogás gerado a partir deste, pode ser utilizado como combustível, com uso em turbinas, motores a gás e caldeiras para produção de energia elétrica. Dessa forma, objetivou-se avaliar a substituição da água no processo de digestão anaeróbica do dejeto bovino pelo lodo de piscicultura. O experimento foi conduzido no Laboratório de Eletrificação Rural e Energias Alternativas do Departamento de Engenharia da UFRRJ. Utilizaram-se protótipos de biodigestores anaeróbios de bancada no modelo indiano, sendo o sistema de abastecimento a batelada. Os substratos utilizados nos processos de monodigestão anaeróbica e codigestão anaeróbica foram o lodo de piscicultura (LP) e dejeto de bovino (DB), nas concentrações de 100:0, 75:25, 50:50, 25:75 e 0:100 LP:DB. Por meio da realização do teste de queima do biogás, para detecção de presença ou não de metano, em quantidade suficiente para manter a chama, confirmou-se a presença de biogás a partir da terceira semana. Os modelos matemáticos Sigmoide de Boltzmann para as relações 75:25 e 0:100 LP:DB e Gompertz para 50:50 e 25:75 LP:DB foram considerados os melhores para estimar as curvas de cinética de produção acumulada de biogás. A relação 25:75 LP:DB apresentou maior valor de produção acumulada de biogás, sendo de 13,55 L em 16 semanas. O potencial de produção acumulada, demonstrou aproveitamento superior a 90% da eficiência energética para combustíveis fosseis comparado a relação 0:100 LP:DB. Portanto, conclui-se que o lodo de piscicultura ofereceu melhorias na codigestão anaeróbica em relação a monodigestão anaeróbica, sendo um substrato de grande importância para a geração de energia na produção de biogás. Ao realizar a substituição de um bem nobre como a água, tornou-se um sistema sustentável nos pilares das dimensões social, econômica e ambiental adequado.

The application of pesticides is essential in modern agricultural production. The concept of drift refers to the undue displacement of a product, which moves to areas outside the intended target, usually due to air currents. The aim of this study was to evaluate the drift potential of conventional spray tips and those incorporating drift reduction technology, at wind speeds both suitable and unsuitable for application. The following spray tips were used: ConeJet TXVS12, Teejet TT 110-02, Teejet TTI 110-02, and Hypro GA110-03. A wind tunnel was used to generate and control the flow of air. The pressure used was 300 kPa. The wind speeds were 6 and 10 km h⁻¹. The spray bar was mounted with the spray tip 50 cm from the ground. The spray solution included water and tracer dye. Polyethylene thread was used for the collectors, which were placed at four different distances (1, 2, 3, and 4 m) and five different heights (0.1, 0.2, 0.3, 0.4, and 0.5 m). The liquids were analysed in a spectrophotometer. At a wind speed of 10 km h⁻¹, a distance of 1 m and a height of 0.1 m, the drift values were 13.41%, 7.15%, 3.13%, and 5.11% for the ConeJet TXVS12, TT 110-02, TTI 110-02, and GA110-03, respectively. It was found that drift potential increased with the increase in wind speed but was reduced with the increase in distance and height. Drift reduction technology using air induction proved to be the best strategy when choosing the correct spray tip for reducing drigt. A aplicação de defensivos é essencial para a produção agrícola moderna. O conceito de deriva é dado pelo deslocamento de produto de maneira indevida, transferindo-se para lugares fora do alvo determinado, geralmente por movimentos de correntes de ar. Objetivou-se avaliar o potencial de deriva das pontas com tecnologia redutora de deriva e convencional, em velocidades do ar adequada e inadequada para aplicação. As pontas utilizadas foram: ConeJet TXVS12, Teejet TT 110-02, Teejet TTI 110-02 e Hypro GA110-03. Foi utilizado túnel de vento para gerar e controlar o fluxo de ar. A pressão utilizada foi de 300 kPa. As velocidades do vento utilizadas foram de 6 e 10 km h-1. A barra de pulverização foi montada com a ponta a 50 cm do solo. O líquido pulverizado foi uma solução de água com corante traçador. Os coletores utilizados foram fios de polietileno, dispostos em quatro distâncias (1, 2, 3 e 4 m) e cinco alturas (0,1, 0,2, 0,3, 0,4 e 0,5 m). Os líquidos foram analisados em espectrofotômetro. Na condição de 10 km h-1, distância de 1 m e altura de 0,1 m, os valores de deriva foram de 13,41, 7,15, 3,13 e 5,11% para ConeJet TXVS12, TT 110-02, TTI 110-02 e GA110-03, respectivamente. Concluiu-se que o potencial de deriva aumentou com o aumento da velocidade do ar, entretanto, reduziu com o aumento da distância e da altura. A tecnologia redutora de deriva de indução de ar mostrou-se como a melhor estratégia na escolha da ponta para redução de deriva.

The major problems of public health, environmental impact, and energy dependence due to conventional fuels can be solved by using biogas from biodigesters. Therefore, the objective of this paper was to evaluate the energy potential of using biogas in the replacement of firewood and liquefied petroleum gas (LPG). For the biogas production, Indian model batch digesters were used in a batch supply system. Those were supplied with 100: 0, 75:25, 50:50, 25:75 and 0:100 sewage sludge: cattle manure (SS:CM). The calculation of the energy conversion was based on the accumulated biogas production, biogas production potential, the amount of waste produced by dairy cattle in a rural property and the equivalence of one cubic meter of gas with wood and LPG. In general, the adoption of biodigesters in rural properties to generate biogas for thermal energy consists of a viable and sustainable technology, regardless of the number of animals in the property. The use of sewage sludge antecipated biogas production, with the highest biogas production potential being 25:75 SS:CM. The financial savings obtained by the owner and /or community when installing a biodigester can be invested in the rural property. Therefore, it is concluded that there is a feasibility to replace firewood and LPG with biogas.