THE EFFECT OF ROTOR ROTATION SPEED ON DECREASED LABORATORY LIQUID WASTE POLLUTING PARAMETERS

<span id="docs-internal-guid-ee22e381-7fff-07aa-8160-5bce2ec61810"><span>aboratory wastewater is produced through laboratory activities. Laboratory wastewater can have a large impact on the environment if it is not processed before being discharged into the water body. Laboratory waste treatment can be carried out using suspended growth technology to reduce pollutant loads, especially Biological Oxygen Demand (BOD</span><span><span>5</span></span><span>) and Chemical Oxygen Demand (COD). </span><span>Aims:</span><span> This study aims to treat wastewater produced by the activity of laboratory using suspended growth technology. </span><span>Methodology and Results:</span><span> This research was conducted by finding the most efficient rotor rotation in degrading the load of BOD5 and COD pollutants. The reactor used is a Mixed Flow Reactor type reactor made of acrylic material with a thickness of 5.5 mm. The reactor is arranged into three series with the same sampling time and different rotor turns that expressed in rotors per minute (rpm). The reactor series consists of Reactor I with 50 rpm rotor rotation speed, 100 rpm Reactor II and 150 rpm Reactor III. Processing is carried out using 8 hours of detention time and variation of sampling time every 8 hours. </span><span>Conclusion, significant and impact study:</span><span> From the results of the study obtained the highest level of effectiveness of reducing pollutant load on processing using 150 rpm rotor rotation and 40 hours sampling time which is 94.6% for BOD</span><span><span>5 </span></span><span>parameters and 94.4% for COD parameters.</span></span>

Losses in the inlet path of a two-rotor vacuum pump

A model of the inlet path of a two-rotor vacuum pump of the Roots type is developed. In the Ansys Fluent package, numerical calculations of the gas flow in the inlet path were carried out at various inlet pressures, pressure drops and rotor rotation angles. The obtained gas mass flow coefficients are in good agreement with the experimental ones. Keywords: two-rotor vacuum pump, inlet path, mass flow coefficient, CFD. [email protected]

Determining the effect of stator groove geometry in a traction synchronous reluctance motor with permanent magnets on the saw-shaped electromagnetic moment level

This paper reports the model of a magnetic field of the synchronous reluctance motor with permanent magnets that was developed on the basis of a finite-element method. The model was implemented in the FEMM finite-element analysis programming environment involving the application of the Lua-based script. The model makes it possible to determine the dependence of the engine's electromagnetic moment on the rotor rotation angle. Determining the level of a saw-shaped moment is important for assessing its harmful effect on the structural elements of the traction motor and the drive in general. The results of digital modeling have established the dependences of the electromagnetic moment on the rotor rotation angle. The moment has a variable component – the saw-shaped moment, whose amplitude for open grooves under a rated load mode is 182 Nm, and for semi-open grooves ‒ 90 Nm. The use of semi-open grooves exerts a positive effect on eliminating the saw-shaped moment in a synchronous reluctance motor with permanent magnets and may be recommended for further application on engines of this type. Semi-open grooves reduce the opening of the stator groove by 2 times and lead to a smoother flux distribution under the gear division. That reduces the oscillations of the main magnetic flux. The proposed application of semi-open stator grooves makes it possible to reduce by more than 2 times the level of a saw-shaped moment of the synchronous reluctance motor with permanent magnets under a rated mode. It has been determined that a rather positive factor is an increase of 4.8 % in the average motor moment value under a rated mode when using semi-open grooves. This is due to a decrease in the average value of magnetic resistance to the main magnetic flux. Therefore, with a simultaneous decrease in the moment's fluctuations, the transition to semi-open grooves makes it possible to improve the mass-dimensional indicators of the motor in general.

ANALISIS PENGARUH JUMLAH SUDU TERHADAP EFISIENSI TURBIN PELTON DENGAN TEKANAN KONSTAN

One of the renewable energy sources that can be used for electricity generation is the Pelton turbine. The purpose of this study was to determine the effect of the number of blades on the efficiency of a Pelton turbine with constant pressure. This research was conducted at the Unihaz mechanical engineering laboratory by varying the number of blades, namely 9 blade turbines and 12 blades. Tests were carried out by giving load gradually to the turbine until the turbine rotor rotation stopped rotating. The results show that in the turbine test with blades 9 the maximum rotation achieved is 698.2 rpm and the maximum rotor rotation is 714.5 rpm at blade 12. Likewise, the torque coefficient and power coefficient achieved by the turbine with 12 are greater when compared to the 9 blades. Meanwhile, the efficiency that can be achieved by turbines with 9 blades is 71% and at 12 blades is 79%. From this it can be concluded that the number of blades affects the rotation, torque coefficient, power coefficient and efficiency of the Pelton turbine with constant pressure.

EFFECT OF MAGNETIC FIELD ON RHEOLOGICAL PROPERTIES OF CELLULOSE ETHERS SOLUTIONS

The rheological properties, structure and phase transitions of hydroxypropyl cellulose in ethanol, dimethyl sulfoxide, ethylene glycol solutions and ethylcellulose in dimethylformamide solutions are studied using viscometry, the cloud-point method, polarization microscopy, the optical interferometry and a polarization photoelectric apparatus in the temperature range 280-360 K. The temperature-concentration regions of isotropic and anisotropic phases are determined for all systems. The type of boundary curves of phase diagrams is compared with the chemical structure of macromolecules. It is shown that the constant magnetic field (3.6 kOe) leads to the orientation of macromolecules in solutions. The domain structure arising in solutions is fixed after evaporation of a solvent and shown in orientation of strips of the film relief. It was found that the flow curves of all solutions at 298 K in the range of shear rates from 0 to 15 s-1 are typically for the non-Newtonian liquids. It was found that the magnetic field leads to an increase in the viscosity of isotropic solutions and a decrease in the viscosity of anisotropic solutions. Both effects depend on the direction of the magnetic field lines. When the rotor-rotation axis is parallel to the direction of power lines of the magnetic field the change in the viscosity of solutions is greater than that at perpendicular orientation of the rotor-rotation axis and power lines of the magnetic field. The results are discussed using representations about the changes in the macromolecule conformation and in the size and shape of the supramolecular particles in the solutions during flow under a magnetic field with different orientation of the power lines.

Physiological quality of mechanically harvested chickpea seeds

Our objective was to evaluate the occurrence of mechanical damage in chickpea seeds with the combination of two harvester speeds (2.5 and 3.5 km.h-1) and three adjustments for rotor rotation speeds (500, 700, and 850 rpm). Harvesting was carried out in a seed production field. Seeds were evaluated for purity, germination (G), first count (FC), germination speed index (GSI), hypochlorite, electrical conductivity, and tetrazolium tests. There was an effect of harvester speeds on seed physiological quality for the first count (FC), germination (G), germination speed index (GSI), especially when combining with high rotor rotation speed. In these cases, the speed of 2.5 km.h-1 resulted in lower values. This harvester speed also had worse results when combining with 850 rpm for purity and hypochlorite tests. The tetrazolium test was not efficient in identifying differences in seed quality. There was no significant interaction between harvester speeds and rotor rotation speeds for the conductivity test. Evaluating the harvester speed’s isolated effect (3.5 km.h-1), we identified problems in seed vigor due to the higher value of exudates in the electrical conductivity test. Low harvester speed (2.5 km.h-1) associated with high rotor rotation speeds (700 and 850 rpm) causes a reduction of the physical and physiological quality of seeds.

Speed-Torque Characteristics of Torque Motor with Tape Winding Stator

The speed-torque characteristics of a torque motor with a new type of active element – the tape winding is considered. The analytical studies of the motor speed-torque characteristics determination is difficult because it is required to take into account the distributed current flowing through the winding elements. This leads to the numerical methods application, in particular, COMSOL Multiphysics software based on the finite element method (FEM). Attention is paid to the changing of the motor developed torque in the presence of EMF created in the winding during the rotor rotation. It is shown that the motor torque with a rotor rotation frequency changing depends mainly on the nature of the distributed current lines flowing through the winding elements, despite the fact that the consumed current value changes to a lesser extent. The obtained speed-torque characteristics of the torque motor has a form similar to ones of separately excited DC motors. The research results allow assessing the expected characteristics of the motor model and are an integral part of the developed design policy of the torque motor with the tape winding stator.