Efficiency of pneumatic and horizontal perforated disk meter mechanism in corn no-tillage seeders in soil with different mobilization reports

This work objectified to evaluate the efficiency of two meter mechanism of corn seeds when submitted to different forward speed and soil management system during the non-tillage seeding. It was used a factorial design in randomized blocks. The factors whose effects were examined were related to the seeders with pneumatic and horizontal disk meter mechanisms for the distribution of the seeds, to the set tractor-seeder forward speeds (4.4; 8.0 and 9.8 km h-1), and to the soil management system considering the corn no-tillage seeding over minimum tillage with chisel plow and the no-tillage system for the seeding of oat culture (Avena strigosa Schreb). It was verified that the forward speed didn't influence the initial and final stands of plants but it interfered in the regularity of longitudinal distribution of plants. The smallest speed provided the largest percentile of normal spacing between plants. The pneumatic meter mechanism presented better performance than the horizontal disk perforated in the longitudinal distribution of plants. About corn productivity aspect it's indifferent the recommendation of use for pneumatic and perforated horizontal disk meter mechanism of seeds.

A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates.

Comparison of estimation methods of soil strength in five soils

In agriculture, the soil strength is used to describe the susceptibility to deformation by pressure caused by agricultural machine. The purpose of this study was to compare different methods for estimating the inherent soil strength and to identify their suitability for the evaluation of load support capacity, compaction susceptibility and root growth. The physical, chemical, mineralogical and intrinsic strength properties of seven soil samples, collected from five sampling pits at different locations in Brazil, were measured. Four clay (CS) and three sandy clay loam (SCL) soils were used. The clay soils were collected on a farm in Santo Ângelo, RS (28 º 16 ' 16 '' S; 54 º 13 ' 11 '' W 290 m); A and B horizons at the Universidade Federal de Lavras, Lavras, MG (21 º 13 ' 47 '' S; 44 º 58 ' 6'' W; 918 m) and on the farm Sygenta, in Uberlandia, MG (18 º 58 ' 37 '' S; 48 º 12 ' 05 '' W 866 m). The sandy clay loam soils were collected in Aracruz, ES (19 º 47 ' 10 '' S; 40 º 16 ' 29 '' W 81 m), and on the farm Xavier, Lavras, MG (21 º 13 ' 24 '' S; 45 º 05 ' 00 '' W; 844 m). Soil strength was estimated based on measurements of: (a) a pneumatic consolidometer, (b) manual pocket (non-rotating) penetrometer; and (c) automatic (rotating) penetrometer. The results of soil strength properties were similar by the three methods. The soil structure had a significant influence on soil strength. Results of measurements with both the manual pocket and the electric penetrometer were similar, emphasizing the influence of soil texture. The data showed that, to enhance the reliability of predictions of preconsolidation pressure by penetrometers, it is better to separate the soils into the different classes, rather than analyze them jointly. It can be concluded that the consolidometer method, although expensive, is the best when evaluations of load support capacity and compaction susceptibility of soil samples are desired.

Emprego de nebulizador pneumático de ICP-MS como câmara de diluição em sistemas de injeção em fluxo para determinações multielementares

An automatic dispenser based on a flow-injection system used to introduce sample and analytical solution into an inductively coupled plasma mass spectrometer through a spray chamber is proposed. Analytical curves were constructed after the injection of 20 to 750 µL aliquots of a multielement standard solution (20.0 µg L-1 in Li, Be, Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, Se, Sr, Ag, Cd, Ba, Tl, Pb) and the acquisition of the integrated transient signals. The linear concentration range could be extended to ca. five decades. The performance of the system was checked by analyzing a NIST 1643d reference material. Accuracy could be improved by the proper selection of the injected volume. Besides good precision (r.s.d. < 2%), the results obtained with the proposed procedure were closer to the certified values of the reference material than those obtained by direct aspiration or by injecting 125 µL of several analytical solutions and samples.

Combinación de sistemas de flujo de baja y alta presion para la determinacion de Mg, Ca y Sr en salmueras por espectrofotometria de absorcion atomica con llama

This article describes the combination of low- and high-pressure flow systems for the determination of Magnesium, Calcium and Strontium by flame atomic absorption spectrometry (FAAS). In the low-pressure system a short C-18 RP column (length 0,5 cm) was utilized for the preconcentration/matrix separation step, xylenol orange was used as chelating agent and tetrabutylamonium acetate for ion pair formation. The hydraulic high pressure nebulization (HHPN) was used for sample transport and sample introduction in the high pressure system. The repeatabilities and detection limits for Mg, Ca and Sr were determined and compared with those obtained by pneumatic nebulization (PN). The results show that the detection limits obtained using the HHPN for Mg, Ca and Sr are between 1.5 to 2 times better than those obtained by PN when the signal transient was measured in area. The system presented a sampling frequency of 130 h-1 for direct determination of Mg, Ca or Sr in samples of saturated sodium chloride used in the production of chlorine and sodium hydroxide.

Propulsor pneumático versátil e isento de pulsação para sistemas de análise em fluxo

Aquarium air pumps are proposed and evaluated as pneumatic liquid propulsion devices for flow injection and continuos flow analysis (FIA and CFA) systems. This kind of pump is widely available at a very low cost and it can sustain a pressure around of 4 psi (0.28 bar) indefinitely. By applying this air pressure onto a solution contained in a reservoir flask, it is possible to reach flow rates of up to 12.5 mL min-1 for circuits comprising reactors, made from 0.8 i.d. tubing with a length of 100 cm. The precise adjustment of flow rate below the maximum one can be made with a simplified needle valve or inserting in series a short length of capillary tube. The absence of flow pulsation is a definite advantage in comparison with peristaltic pumps, especially when amperometric detection is elected, as confirmed experimentally in FIA and CF applications.

Evaluation of tractive performance of four agricultural tractors in laterally inclined terrain

The present work aimed to evaluate the tractive performance of four agricultural tractors with auxiliary front traction in function of six lateral inclinations in a lateral track of trials, which belongs to the Agronomic Sciences Faculty from the São Paulo State University, Campus of Botucatu. The lateral inclinations were 0; 5; 10; 15; 20 and 25 degrees. In all of these situations, the tractors operated with predetermined load of an imposed traction to the pulled tractor of 40 kN in the inclination of 0 degrees. Hence a delineation in random blocks was used, considering six inclinations and four tractors, and with three repetitions for each treatment. The analyzed variables were slippage, tractive force, hourly fuel consumption, and speed. It was concluded that the pneumatic tire configurations influenced in the tractive performance of the tractors, as they increased the lateral inclinations of the terrain.

Comparison of metering mechanisms of corn seed

It was compared the performance of the metering mechanism of corn seeds (Zea mays) in direct seeding in an area of ​​200 ha, a property in Piraí do Sul, State of Paraná - PR, in Brazil. It was seeded 4 maize hybrids, 50 ha of each, with seeds of different sieves. The experiment was conducted in a randomized block design (RBD), with 3 treatments and 9 repetitions for each corn hybrid. The treatments were the pneumatic seed of metering mechanisms, horizontal perforated disc with and without ramp®. The plots were 40 m² and were distributed at the early, middle and late sowing. The variables analyzed in each corn hybrid were initial population, faulty spacing, multiple spacing, acceptable spacing, and yield components. As there were no significant differences in the variables, it was concluded that the quality of seeding with different systems of distribution was similar in the different sieves of distributed corn seeds.

Drop Size Measurements in a Laboratory Scale Venturi Scrubber

Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by droplets formed by liquid atomisation, usually in the venturi throat. The size of the droplets formed is of fundamental importance to the performance of the equipment, both in terms of pressure drop and collection efficiency. In this study, drop sizes in a cylindrical laboratory scale venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90 m/s and 0.5 to 2.0 l/m3, respectively. Water was inserted as perpendicular jets at the beginning of the throat. Measurements were performed at three positions: two located along the throat, and the last one at the end of the diffuser. The data presented here are a typical example of pneumatic atomisation and can be relevant to other industrial applications such as combustion and engine technology. Finally, results are compared to available correlations and the validity of these equations is discussed.

Hemodynamic responses to acute aortic coarctation in conscious sinoaortic denervated rats

The hemodynamic responses to acute (45 min) partial aortic constriction were studied in conscious intact (N = 7) or sinoaortic denervated (SAD) adult male Wistar rats (280-350 g, N = 7) implanted with carotid and femoral arterial catheters, a pneumatic cuff around the abdominal aorta and a pulsed Doppler flow probe to measure changes in aortic resistance. In addition, the hypertensive response and the reflex bradycardia elicited by total (N = 8) vs partial (N = 7) aortic constriction (monitored by maintenance of the pressure distal to the cuff at 50 mmHg) were compared in two other groups of intact rats. Intact rats presented a smaller hypertensive response (26 to 40% above basal level) to partial aortic constriction than SAD rats (38 to 58%). The calculated change in aortic resistance imposed by constriction of the aorta increased progressively only in intact rats, but was significantly smaller (193 to 306%) than that observed (501 to 591%) in SAD rats. Intact rats showed a significant bradycardia (23 to 26% change in basal heart rate) throughout coarctation, whereas the SAD rats did not (1 to 3%). Partial or total occlusion of the aorta induced similar hypertensive responses (37-38% vs 24-30% for total constriction) as well as reflex bradycardia (-15 to -17% vs -22 to -33%) despite a greater gradient in pressure (97-98 vs 129-140 mmHg) caused by total constriction. The present data indicate that the integrity of the baroreflex in intact rats can cause the hypertensive response to level off at a lower value than in SAD rats despite a progressive increase in aortic resistance. In addition, they also indicate that the degree of partial aortic constriction by maintenance of the pressure distal to the cuff at 50 mmHg already elicits a maximal stimulation of the arterial baroreflex

Noninvasive assessment of endothelial function and ST segment changes during exercise testing in coronary artery disease

Endothelial function (EF) plays an important role in the onset and clinical course of atherosclerosis, although its relationship with the presence and extent of coronary artery disease (CAD) has not been well defined. We evaluated EF and the ST segment response to an exercise test in patients with a broad spectrum of CAD defined by coronary angiography. Sixty-two patients submitted to diagnostic catheterization for the evaluation of chest pain or ischemia in a provocative test were divided into three groups according to the presence and severity of atherosclerotic lesions (AL): group 1: normal coronaries (N = 19); group 2: CAD with AL <70% (N = 17); group 3: CAD with AL ≥70% (N = 26). EF was evaluated by the percentage of flow-mediated dilatation (%FMD) in the brachial artery during reactive hyperemia induced by occlusion of the forearm with a pneumatic cuff for 5 min. Fifty-four patients were subjected to an exercise test. Gender and age were not significantly correlated with %FMD. EF was markedly reduced in both groups with CAD (76.5 and 73.1% vs 31.6% in group 1) and a higher frequency of ischemic alterations in the ST segment (70.8%) was observed in the group with obstructive CAD with AL ≥70% during the exercise test. Endothelial dysfunction was observed in patients with CAD, irrespective of the severity of injury. A significantly higher frequency of ischemic alterations in the ST segment was observed in the group with obstructive CAD. EF and exercise ECG differed among the three groups and may provide complementary information for the assessment of CAD.

Increased immunohistochemical expression of YKL-40 in the spleen of patients with portal hypertension

YKL-40 has been identified as a growth factor in connective tissue cells and also a migration factor in vascular smooth muscle cells. To a large extent, the increase of serum YKL-40 is attributed to liver fibrosis and asthma. However, the relationship of the expression and clinical/prognostic significance of YKL-40 to the splenomegaly of patients with portal hypertension is unclear. In the present study, the expression of YKL-40 was studied by immunohistochemistry in 48 splenomegaly tissue samples from patients with portal hypertension and in 14 normal spleen specimens. All specimens were quickly stored at -80°C after resection. Primary antibodies YKL-40 (1:150 dilution, rabbit polyclonal IgG) and MMP-9 (1:200 dilution, rabbit monoclonal IgG) and antirabbit immunoglobulins (HRP K4010) were used in this study. The relationship of clinicopathologic features with YKL-40 is presented. The expression of YKL-40 indicated by increased immunochemical reactivity was significantly up-regulated in splenomegaly tissues compared to normal spleen tissues. Overexpression of YKL-40 was found in 68.8% of splenomegaly tissues and was significantly associated with Child-Pugh classification (P = 0.000), free portal pressure (correlation coefficient = 0.499, P < 0.01) and spleen fibrosis (correlation coefficient = 0.857, P < 0.01). Further study showed a significant correlation between YKL-40 and MMP-9 (correlation coefficient = -0.839, P < 0.01), indicating that YKL-40 might be an accelerator of spleen tissue remodeling by inhibiting the expression of MMP-9. In conclusion, YKL-40 is an important factor involved in the remodeling of spleen tissue of portal hypertension patients and can be used as a therapeutic target for splenomegaly.

Effects of disturbed blood flow during exercise on endothelial function: a time course analysis

This study aimed to examine the time course of endothelial function after a single handgrip exercise session combined with blood flow restriction in healthy young men. Nine participants (28±5.8 years) completed a single session of bilateral dynamic handgrip exercise (20 min with 60% of the maximum voluntary contraction). To induce blood flow restriction, a cuff was placed 2 cm below the antecubital fossa in the experimental arm. This cuff was inflated to 80 mmHg before initiation of exercise and maintained through the duration of the protocol. The experimental arm and control arm were randomly selected for all subjects. Brachial artery flow-mediated dilation (FMD) and blood flow velocity profiles were assessed using Doppler ultrasonography before initiation of the exercise, and at 15 and 60 min after its cessation. Blood flow velocity profiles were also assessed during exercise. There was a significant increase in FMD 15 min after exercise in the control arm compared with before exercise (64.09%±16.59%, P=0.001), but there was no change in the experimental arm (-12.48%±12.64%, P=0.252). FMD values at 15 min post-exercise were significantly higher for the control arm in comparison to the experimental arm (P=0.004). FMD returned to near baseline values at 60 min after exercise, with no significant difference between arms (P=0.424). A single handgrip exercise bout provoked an acute increase in FMD 15 min after exercise, returning to near baseline values at 60 min. This response was blunted by the addition of an inflated pneumatic cuff to the exercising arm.

Study of the flash drying of the residue from soymilk processing - "okara"

The objective of this research project was to study the drying of soymilk residue in a pneumatic flash dryer, using response Surface Methodology (RSM), and to evaluate the quality of the dried residue. Soymilk residue, also known as okara, was provided by a Brazilian soymilk factory. RSM showed that for a 120 second drying cycle, the lower the residue moisture contents (y) obtained, the higher the recirculation rates (x1), regardless of the air drying temperature (x2), and it could be expressed by the equation y = 7.072 - 7.92x1, with R² = 92,92%. It is possible to obtain okara with 10% of moisture (dwb) under the condition x1=1.25, equivalent to RR = 61%, with air drying temperatures ranging from 252 °C to 308 °C. The dried okara obtained through Central Compound Rotational Design (CCRD) presented a centesimal composition similar to the okara dried in a tray dryer, known as the original okara. There were significant variations (p < 0.05) in the Emulsifying Capacity (EC), Emulsion Stability (ES) and Protein Solubility (PS) between the dehydrated residues obtained. It was concluded that the flash drying of okara is technically feasible and that the physicochemical composition of the residue was not altered; on the contrary, the process promoted a positive effect on the technological functional properties.

Physical, chemical, technological and sensory characteristics of Frankfurter type sausage containing okara flour

The addition of okara flour to an emulsified meat product (Frankfurter type sausage) was evaluated based on the physical, chemical, technological, and sensory characteristics of the final product. Okara, residue from soymilk production, was provided by two soymilk producing companies whose production systems were based on the hot disintegration of the decorticated (company B) or undecorticated (company A) soybeans. The okara was dehydrated using a flash dryer and then ground into flour (>420 µm). However, The okara flours A and B showed approximately the same amount of protein (35 and 40 g.100 g-1 dwb). However, the okara flour A presented higher values (p < 0.05) for all technological functional properties studied (emulsification capacity, emulsion stability, protein solubility, and water hold capacity) than those of okara flour B. The A and B okara flours were used in a frankfurter sausage formulation as substitution of 1.5% and 4% of meat. The results showed that the sausages containing okara flours A and B, as well as the control sausage, were accepted by the sensory panel. Moreover, there were no significant differences (p < 0.05) in the physical (color, objective texture, and emulsion stability) and chemical (pH and proximate composition) measurements of the sausages with and without the okara flour.