The present study aimed to evaluate the efficiency of hypertonic saline solution (HSS) as a novel treatment of acute ruminal lactic acidosis (ARLA) in cattle, focusing on urinary excretion of acids. Twelve cannulated steers were submitted to experimentally induced ARLA by adminis- tering sucrose into the rumen. Twenty hours later, the cattle were randomly divided into two equal groups. The first group was treated with 7.5% HSS (5 mL/kg) over 15 min, and isotonic saline solution (ISS; 20 mL/kg) for the subsequent 165 minutes. The control group was administered ISS instead of HSS. Rumen and urine samples were collected at different times during the experiment from the baseline to 64 h post-induction. The induction caused a medium-to-moderate ruminal acidosis, and a moderate degree of systemic acidosis and dehydration. Steers treated with HSS increased by 50% its glomerular filtration rate (1.61 mL/min) compared to ISS group (1.06 mL/ min; p<0.03). The overall volume of urine excreted by HSS group was higher than that in ISS group (1.62 L vs 0.7 L; p<0.02). This increase in total volume of urine provided by HSS favored a greater excretion of H+ ions in urine, which was 3.39-fold higher in HSS group (64.3*10-7 vs 18.9*10-7 Mol) as well as lactate (241.7 vs 181.8 mMol) and P urinary excretion (3.8 vs 1.1 mMol) that reduced the urine pH (5.3 vs 5.7). Only the HSS group decreased significantly blood total lactic acid concentration (20.3 %) throughout the treatment. A positive relationship was found between the excretion of urinary phosphorus and urinary pH (r2=0.562). The results showed that this novel treatment with HSS enhanced renal excretion of acids and may be recommended as an additional treatment for cattle with lactic acidosis.

Operation of an electrically controlled beam steering device based on Rochon prism made by use of nematic liquid crystal is modelled numerically. Deflection angles and angular distribution of light intensity in the deflected beam are calculated. Dynamics of the device is studied. Advantage of application of dual frequency nematic liquid crystal is demonstrated. Role of flexoelectric properties of the nematic is analyzed.

In recent years, the Steer-by-Wire (SBW) technology has been gaining popularity and replacing classical steering systems. It plays the most crucial role in autonomous cars where the vehicle must perform maneuvers on its own without driver’s intervention. One of the key components of this system is the steering wheel angle sensor (SAS). Its reliability and performance may affect driver’s life and health. The purpose of this paper is to show a test system to comprehensively evaluate the performance of the steering wheel angle sensor in the SBW system during real-world maneuvers and show how SAS parameters such as accuracy of angle, angular speed etc. affect car trajectory resulting in hit cones.
For this purpose, a test system was built, with the use of virtual test drives based on CarMaker software, CANoe and VTSystem hardware. In order to evaluate its performance, the errors introduced by the system were determined. Additionally, using the realised test system, three commercial steering wheel angle sensors were tested and compared during a virtual test drive. Their errors were determined, as well as their performance in the SBW technology and the consistency of the obtained results with the parameters declared by the manufacturer were verified as well.

The objective of this paper is to present a method of dynamic analysis of the steering system of a passenger car with McPherson suspension. The links of the system are modelled as rigid bodies; however, the method enables flexibility of the steering shaft of the car to be taken into account. The geometry of the system is described by using homogenous transformations. Equations of motion are derived on the basis of the Lagrange equations. In the method proposed, the closed loop oflinks is cut at selected joints and suitable reaction forces are introduced. Dry friction occurring in the steering system is reduced to the prismatic joint between the steering rack and guide. The method can be used in design and optimization of steering systems of passenger cars with McPherson suspension.

The authors present the results of experimental rig study on resistance forces in a rack and pinion steering system without power assistance of a small car with MacPherson front suspension. The influence of a harmonic steering angle excitation, with frequency ranging from I to 3 Hz, and different wheel load conditions on self-returnability, sensitivity, and friction forces in the steering system is studied. These characteristics are responsible for the car directional stability at high-speed of cruising or during braking maneuver, and influence comfort, effort, and good feeling of the car driver. On the basis of experimental results, some parameters (equivalent moment of friction forces and stiffness coefficients) of a simplified model are estimated for different excitations and load conditions.

The paper presents a method for dimensional synthesis of a five-rod guiding mechanism for the front wheels of a car. The goal is to find some unknown coordinates of joint centers of three suspension rods on the basis of given input data describing selected coordinates of other points, rods lengths and desired suspension characteristics for jounce-rebound and steering displacements. The synthesis problem is formulated as a single-criteria optimization procedure with a few substages solved in hierarchical order. The procedures for position and displacement analysis of the spatial multilink mechanism and for determination of the screw axes are also described. A numerical example for the AUDI A4 front ax.le is given.