Uneven Feeding Research Articles

Coupled DEM-MBD-PRM simulations of high-pressure grinding rolls. Part 2: Investigation of roll skewing

Roll skewing is an integral part of the operation of most HPGR designs presently used and is the result of the system attempting to compensate for uneven reaction from the particle bed along the length of the rolls to the applied forces. Several studies in recent years have simulated HPGR performance using the discrete element method (DEM). However, even when coupled to multi-body dynamics (MBD), these simulations have been limited to the description of one-dimensional motion of the rolls. The present work uses a combination of DEM and MBD to describe two-dimensional motion of the floating roll, making predictions of HPGR operation under skewing possible. Simulation case studies were carried out of a pilot-scale HPGR considering the case of uneven feeding, besides cases in which the feed is segregated with respect to particle size and also strength, represented by different median particle fracture energies, fed to each section of the rolls. Results show that the force profile along the bed and the product fineness along the length of the rolls become more uniform if skewing is allowed in the presence of uneven feed.

Investigation of the effect of equal and unequal feeding time intervals on process stability and methane yield during anaerobic digestion grass silage

The effects of equal and unequal feeding intervals, organic loading rates (OLR) and operating temperatures on specific methane production (SMP) during the anaerobic digestion (AD) process were investigated using three pairs of continuously stirred tank reactors (CSTRs). The Pair 1, 2 and 3 CSTRs were operated at psychrophilic (25 ± 2 °C), mesophilic (40 ± 3 °C) and thermophilic (60 ± 2.5 °C) conditions, respectively. After acclimatization, the reactors were fed at an OLR of 1.0 and 1.5gVS/L.d at selected intervals, while maintaining their pH 6.8–7.2 with NH4HCO3 solution. The results showed that during uneven feeding regime (day 8–93), the mean SMP from Pair 1, 2 and 3 reactors were 294.5, 433.5 and 370.2 N mLCH4/gVS fed, respectively. At failing state (day 60–93), the mean concentrations of free ammonia nitrogen (FAN) in the psychrophilic, mesophilic and thermophilic CSTRs were 19.1, 33.7 and 127.2 mg/L; VFAs of 6940.1, 6852.3 and 4694.9 mg HAc/L; which reduced their SMPs to 140, 273.8 and 231.1 N mLCH4/gVS, respectively. Therefore, uneven feeding, trace elements (TEs) deficiency, VFAs accumulation and FAN (for thermophilic) led to CSTRs failure. An even (24-hourly) feeding regime with daily biomass ash-extracts supplement enhanced the recovery of the failed CSTRs. Although, uneven daily feeding conditions led to AD process instability, it favoured SMP in mesophilic CSTRs compared to psychrophilic and thermophilic. These results strongly indicate that the soluble TEs and alkalinity contained in ash-extracts facilitated the recovery of the failed AD reactors and therefore can be used to revive failed AD processes.

Определение рациональных параметров работы вибрационного смесителя для получения мучных сыпучих смесей

Introduction. New long-storage flour baking mixes are a promising direction in the development of healthy diets. The research objective was to identify the rational parameters for using continuous vibration mixers in flour production.
 Study objects and methods. The study featured wheat flour baking mixes. A correlation analysis helped to build mathematical models of the mixing process in vibration mixers using the sequential dilution method. By comparing the smoothing ability of several mixers, the authors identified their feasibility. The research included two full-factor laboratory experiments.
 Results and discussion. The paper gives a brief review of modern mixing equipment and describes the effect of uneven feeding of bulk materials on the quality of the finished mixes. The vertical vibration mixers proved to be an optimal technical solution. The experiment featured the effect of the amplitude A (m), vibration frequency f (Hz), vibration angle β (°), and the height of the vibrofluidized bed on the process.
 Conclusion. The research revealed the following optimal technological parameters: A = 0.0046 m, f = 33.48 Hz, the share of food salt = 0.05. Continuous vibration mixers provided uniform high-quality baking mixes.

Design of a Feeding Device for Penaeus Vannamei Breeding Pond

At present, the mechanization of shrimp culture in China is still low, and most of them are artificially fed. Artificial feeding is not only labor-intensive, but also has the disadvantages of uneven feed throwing. In this paper, a feeding device for Penaeus Vannamei breeding pond is designed, which mainly includes guide trolley, support body, feeding rod, storage plate and storage bucket, the feeding efficiency of Penaeus Vannamei is improved.

Digital technologies in food preparation and distribution

The article considers the analytical review of digital technologies (smart farming) in agro-industry. Such digital technologies include computer programs for calculating the farm animal diet, their advantages and disadvantages are given. The analysis and disadvantages of foreign robotic systems for feeding animals are presented. The results of correlation and regression analysis of the impact of the herd size of farm animals on labor input for their feeding are presented. The impact of the number of feed loading cycles in the hopper and its capacity on the uneven feed distribution by the “Free Stall Feeder” robotic feed distributor using the Mathcad 15 program is shown.

Оцінка рівномірності розподілу та засміченості зерна при його багаторівневому введенні в пневмосепаруючий канал

The uniformity of grain distribution in a pneumatic separation channel is an important factor and it significantly affects the quality of grain cleaning. Indeed, with uneven feeding, impurities entering the pneumatic separating channel, to a large extent, are located in the middle or lower layers of grain flow, which impairs the possibility of their release into the settling chamber. Feeders are used to create a more uniform distribution of grain in the operating area of the pneumatic separating channel. They provide conditions under which grain material is fed into the air stream by a thin layer of directed jet. This feeding can significantly improve the interaction of the components of the input grain material with air, increasing the likelihood of their release, as well as minimize the contact of particles of the grain mixture, which significantly increases the efficiency of air flow. Based on the review and analysis of feeder designs, we have proposed a feeder for multi-level grain introduction. The use of such a feeder can significantly improve the quality of pneumo-separation, but there is a possibility of light impurities in the upper grain layers, which can affect the completeness of the separation of the purified grain. Experimental studies were conducted to determine the effect of multilevel introduction on the content of light impurities in the purified grain along the height of the pneumatic separation channel, as well as to analyze the distribution of grain mixture in the operating separation area. As a result of the conducted research it is determined that the number of involved levels of introduction of the feeding device influences the degree of clogging of the cleared grain, thus, uniformity of distribution of grain improves at increase in quantity of levels. In particular, when using up to 4 levels of the feeder under load qbi = 350 kg/dm•h at each level, the amount of light impurities entering the purified grain is not more than 3% of their total weight in the source material.

Study of existing designs of the peristaltic principle pumps

Peristaltic pumps are used in a wide variety of applications due to their tightness, ease of maintenance and accurate delivery. Nevertheless, the use of peristaltic pumps is limited by their disadvantages: short service life of the working body and uneven feed. This work provides an overview of the existing design solutions for pumps. The main advantages and disadvantages of the most common modern designs of peristaltic pumps are considered. The developed design solutions are presented. These solutions are designed to extend the service life of the elastic working body of the pump. These include a spiral hose design, where hose life is improved by reducing the number of cyclic compressions using just one roller. Another solution is to operate the pump with incomplete compression of the working element, which reduces the stress values and thereby prolongs the service life of the working element. The special shapes of protrusions in the compression area were developed in order to compensate the decrease in flow caused by the operation of the pump with incomplete compression of the working member. The paper provides an overview of solutions to reduce the uneven flow of a peristaltic pump. The simplest of these is the use of multiple parallel channels. In other designs, the elimination of flow pulsations is achieved with a pneumatic damper. There is also a constructive solution, in which a special algorithm of actuation of five squeeze elements is used for uniform supply, each of which compresses only its own section of the pump working body. Based on the analysis, it is shown that in order to eliminate the disadvantages of peristaltic pumps the various methods are used. Nevertheless, those methods need further improvement.

Some design features of sliding current leads

Plastic bending of the electrode wire causes an increase in the required force of its supply to the current supply. This can lead to uneven feed and instability of welding, surfacing and spraying processes. (Research purpose) The research purpose is in considering the behavior of the supplied electrode wire in the current supply and suggest ways of reducing the force of its pushing. (Materials and methods) In order to reduce the force of feeding the wire to the current supply, its bend must be elastic. If the wire must be deformed plastically, it must be bent before entering the current supply and the bend of the current supply channel must correspond to the curvature of the wire. The article presents calculations of the radius of curvature of the wire to assess the behavior of the wire when it bends, at which it begins to deform plastically. (Results and discussion) The article presents results for the bending radii of wires made of various materials, at which they begin to deform plastically. Authors selected for calculations the wire materials and their diameters, which are most often used for electric arc welding and sputtering. With an increase in strength properties and a decrease in wire diameters, their bending occurs elastically at a smaller radius. This information and the described behavior of the wire when it is fed into a sliding current supply can be useful for developers in creating metallization and surfacing equipment. (Conclusions) In order to reduce the force of pushing the wire into the current supply channel, it is desirable to deform it elastically when feeding. For the most commonly used materials for arc welding, surfacing and metallization, the values of the bending radii of the wires at which plastic deformation begins are calculated and presented. When plastic bending of the wire is used to reduce the feed force, it must be bent before the entrance to the current supply channel. The bend of the wire must correspond to the radius of the channel.

Использование двухдискового распределяющего и двухуровневого отражающего устройств камерного протравливателя для повышения качества обработки семян зерновых культур

В последние годы все большее внимание уделяется проведению качественного протравливания семян, что невозможно осуществить без применения камерных протравливателей, работающих по принципу непрерывной подачи семян в камеру протравливания. Существующие камерные протравливатели типа Mobiox Super в конструкциях, которых предусмотрена установка одно- или двух дисковых распределяющих устройств семян пассивного и активного действия, а также одноуровневых отражающих устройств не способны существенно повысить качество протравливания. Поэтому целью научного исследования явилось повышение качества обработки семян зерновых культур разработкой двухдискового распределяющего и двухуровневого отражающего устройств камерного протравливателя. Научная значимость исследований заключается в установлении зависимостей влияния конструктивных параметров на дробление семян. Практическая значимость исследований состоит в разработке протравливателя, оснащенного двухдисковым распределяющим и двухуровневым отражающим устройствами семян способного снизить дробление, влажность семян и увеличить полноту их протравливания. Двухдисковое распределяющее устройство состоит из верхнего кольцевого диска с направителем-делителем в виде катеноида и нижнего сплошного диска с направителем в виде псевдосферы, а двухуровневое отражающее устройство включает в себя отражатель верхнего и нижнего уровней, их применение дает возможность сформировать два равномерных потока семян перед нанесение рабочей жидкости. Для проведения исследований в качестве семенного материала использовали семена яровой пшеницы сорта Радуга, а в качестве протравителя применяли препарат Максим Экстрим. Методика исследований камерного протравливателя предусматривала обоснование рациональных значений его конструктивных параметров, определение посевных качеств семян, влияния диаметра выходного окна лепесткового дозатора на подачу семян, неравномерность подачи и дробление протравливателем, а также проведение сравнительных испытаний разработанного протравливателя Mobiitox Super с базовым Mobiitox Super. Анализ и обработка результатов исследований осуществлялись методами математической статистики. Ценность полученных результатов исследований в том, что при расстоянии от кольцевого диска до отражателя верхнего уровня 60 мм, диаметре отражателя нижнего уровня 350 мм, высоте расположения отражателя верхнего уровня 30 мм и высоте расположения отражателя нижнего уровня 30 мм, наблюдалось наименьшее дробление семян протравливателем 0,05 %. Практическое значение исследований заключается в разработке протравливателя обеспечивающего, по сравнению с базовым, снижение дробления семян после протравливания с 0,12 % до 0,06 %, неравномерности протравливания с 5,6 % до 2,67 %, влажности семян после протравливания с 15,4 % до 15,1 %, и повышение полноты протравливания с 85,6 % до 97,4 %. Таким образом, применение протравливателя, оснащенного двухдисковым распределяющим и двухуровневым отражающим устройствами способно повысить качество протравливания.

A 28-/37-/39-GHz Linear Doherty Power Amplifier in Silicon for 5G Applications

This paper presents the first 28-/37-/39-GHz linear Doherty power amplifier (PA) in silicon for broadband fifth-generation (5G) applications. We introduce a new transformer-based on-chip Doherty power combiner that can reduce the impedance transformation ratio (ITR) in power back-off (PBO) and, thus, improve the bandwidth and power-combining efficiency. We also devise a “driver-PA co-design” method that creates power-dependent uneven feeding in the Doherty PA and enhances the Doherty operation without any hardware overhead or bandwidth compromise. For the proof of concept, we implement a 28-/37-/39-GHz PA fully integrated in a standard 130-nm SiGe BiCMOS process, which occupies 1.8 mm $^{\mathbf {2}}$ . The PA achieves a 52% −3-dB small-signal $\text{S}_{\mathbf {21}}$ bandwidth and a 40% −1-dB large-signal saturated output power ( $\text{P}_{\mathbf {sat}}$ ) bandwidth. At 28/37/39 GHz, the PA achieves +16.8−/+17.1−/+17-dBm $\text{P}_{\mathbf {sat}}$ , +15.2−/+15.5−/+15.4-dBm $\text{P}_{\mathbf {1\,dB}}$ , and superior 1.72/1.92/1.62 times efficiency enhancement over class-B operation at 5.9-/6-/6.7-dB PBO. Moreover, the PA demonstrates multi-gigabit-per-second data rates with excellent efficiency and linearity for 64-quadrature amplitude modulation (64-QAM) in three millimeter-wave (mm-wave) 5G bands. This PA advances the state of the art for Doherty, wideband, and 5G silicon PAs in mm-wave bands. It supports drop-in upgrade for current PAs in existing mm-wave systems and opens doors to compact system solutions for future multiband 5G massive multiple-input multiple-output (MIMO) and phased-array platforms.

Research into the process of loading the surface of a vibrosieve when a loose mixture is fed unevenly

The work examines the influence of uneven feeding of a loose mixture on the process of loading a vibrating sieve. In this work, we established regularities of layer thickness, longitudinal and transverse components of velocity, density of loose mixture and specific load on the entire area of a vibrating sieve at uneven feeding at the inlet. The uneven feed was assigned by using a convex profile, a concave profile, and a triangular profile of the initial velocity for width at the inlet of a sieve. Flow characteristics change equally along the length of a sieve for the profiles considered. Flow characteristics change according to the initial velocity profile for width of the sieve. For a convex profile, the thickness is constant, the surface density and the longitudinal component of the velocity are the greatest along the longitudinal axis of the sieve, and they are the smallest near the side walls, the direction of the transverse component of the velocity is from the longitudinal axis to the side walls. For a concave profile, the thickness is constant, the surface density and the longitudinal component of the velocity are the greatest along the side walls, and they are the smallest along the longitudinal axis, the direction of the transverse component of the velocity is from the side walls to the axis. For a triangular profile, the thickness is constant, the surface density and the longitudinal component of the velocity are the greatest along one side wall, and they are the smallest along the opposite wall, the direction of the transverse component of the velocity is toward the first mentioned side wall. For a convex profile of the initial velocity, the surface is overloaded along the longitudinal axis of the sieve and it is underloaded along the side walls. For a concave profile, the surface is overloaded near the side walls, and it is underloaded along the longitudinal axis of the sieve. For a triangular profile - the surface is overloaded along one side wall and it is underloaded along the opposite one. The largest deviations of the specific load occur near the inlet section of the flow, the smallest ones - near the outlet section. The regularities of distribution of the specific load of the sieve are decisive in the design of feeders and distributors of loose mixtures, as well as in calculation of separation modes

Hyperplastic goiter in two adult dairy cows

Iodine excess and resultant hyperplastic goiter are well documented in neonatal ruminants, but little is reported on iodine excess in adult ruminants and associated histological changes of the thyroid gland. Two adult Holstein cows from a Michigan dairy herd that had lost several other animals had nonspecific clinical signs of illness and were submitted for necropsy. Thyroid glands of one of these 2 animals were grossly and markedly enlarged, and histologically, thyroid glands from both animals had regions of cystic nodular hyperplasia and follicular atrophy. Thyroid glands from both animals had markedly elevated iodine concentrations. Investigation into the potential source of excessive iodine on the farm revealed multiple sources of supplemental dietary iodine and probable uneven feed and mineral mixing. Based on the findings of this investigation, adult cattle could be susceptible to excessive doses of iodine. Possibility of previous iodine deficiency before supplementation period, with subsequent development and persistence of thyroid hyperplasia and cystic change, cannot be completely excluded. Current findings suggested that iodine excess in adult cattle can result in nodular hyperplastic goiter. Use of iodized salt in mineral supplements in adult dairy herds is common practice, and accidental excessive iodine supplement may be more common than reported. Recognizing gross and histological thyroid gland changes, consisting of concurrent cystic follicular hyperplasia, atrophy, and fibrosis should raise suspicion of iodine excess and/or prior deficiency in a cattle herd, and ancillary tests such as serum iodine measurements should be part of the diagnostic workup in suspected cases.

The transformation approach of complex design bearing for analytic definition its integral characteristics

The approximate analytical solution of Reynolds equation for complex design bearing is considered. Such bearings have variable curvature bearing faces, uneven feeding of gas-film lubrication and unsymmetrical distribution of thermodynamic parameters in a gap, that makes difficult to find analytical solution in respect to integral characteristics, such as load capacity and stiffness. In this work an approach of transforming complex aerostatic design bearing to a combination of similar conventional bearings (i.e. load capacity and stiffness of both bearing are equal) is suggested. The difference between both bearing designs is determined. The conventional bearings have typical solutions of Reynolds equation, which allows improved solutions for base bearing modeling and analysis. Use of this approach over numerical calculation of complex bearing design is the definition of functional relations between its parameters.

Intraspecific growth variation among rainbow trout and brook trout: impact of initial body weight and feeding level

This study describes growth variation within groups of salmonids and the relation to initial fish weights and feeding levels. PIT-tagged rainbow trout (RT) and brook trout (BT) of start weight 120–170 g were reared in separate tanks for 9 weeks. Both species were fed each day either a high ration close to satiation (H) or half of this ration (L). Four experimental groups (RT-H, RT-L, BT-H, BT-L) were studied with regard to their propensity to increase weight in accord with their initial weight. The slope of the regression line between initial weights (g) and weight increases for individuals in each tank in each period was applied as indicator for this propensity (termed “slope”). All calculated slopes in the experiment were positive which indicates the general ability of weighty fish to gain more weight than smaller individuals. The average slope during all 9 weeks was 2–4 times higher for RT-L (5.91) than for all other groups (RT-H: 1.50, P 0.05). The magnitude of slopes decreased over time (weeks 0–3:4.27, weeks 3–6:3.02 and weeks 6–9:1.74, P < 0.05). The observed differences in weight gains between experimental groups were reflected in differences in coefficients of variations (CVs) for body growth. RT had larger body weight (BW) CVs compared to BT (0.257 vs. 0.206, P < 0.01) indicating more uneven feed share among RT than among BT in general. RT-L had significantly higher BW CVs than all other groups (0.300 vs. 0.184–0.229, P < 0.01). The observed differences in weight gains enhance size variations in terms of higher CVs, and this may have implications for feeding tactics in aquaculture where large size variations in groups may be disadvantageous to fish farmers.

The accretion activity of the Ae Herbig star CQ Tau

Results of spectral observations of the isolated Ae Herbig star CQ Tau obtained in 1995–1998 in the Hα line and near the sodium resonance doublet are presented, together with simultaneous photometric monitoring of the star. CQ Tau is a member of the family of young UX Ori stars with nonperiodic Algol-like brightness decreases. The star is surrounded by an accretion disk, in which its emission-line spectrum and part of its absorption-line spectrum are formed. The strong variability of the Hα, D NaI, and HeI 5876 A lines testifies that the gaseous disk is appreciably inhomogeneous in both the radial and azimuthal directions. This inhomogeneity probably results from uneven feeding by the circumstellar material from the peripheral regions of the circumstellar disk. Over the four years of observations, we observed the star in deep minima three times (ΔV∼2). On these nights, an increase in the Hα equivalent width followed the decrease in radiation flux. In the two deepest minima, the normally two-component line profile had only a single component with a nearly symmetrical profile. This behavior of the Hα line is in good agreement with the results of numerical modeling of Algol-like minima and can be used to estimate the parameters of the dust clouds eclipsing the star and inner accretion disk. These estimates suggest that the circumstellar dust clouds can approach very close to the star and be sublimated there.