Design and Fabrication of an Automatic Fish Feeder Prototype Suits Tilapia Tanks

The conventional methods of supplying feed to tilapia tanks are ineffective. It is better to find new a automatic feeder saving pellets from crushing and cohesion without hitting pellets during feeding at a predetermined interval of time and an accurate amount of food with a larger surface area covered by pellets. Developing-country fish farmers use manual feeding to be more cost-effective than with costly mechanized feeding, so this research aimed to design and construct an automatic fish feeder prototype to feed tilapia in a recirculation aquaculture system’s tank. The performance of the prototype was studied after it was designed and installed. The dispensed feed operated by a DC motor located underneath the pellet hopper and the feed material was discharged into the tank through a gate in the bottom of the feeder. Three pellet sizes, three rotation speeds, and three feeder heights from the water’s surface were used to test the automatic feeder’s efficiency. The results showed that the optimal speed for the automatic feeder was 14 rpm with a height of 70 cm, resulting in a distribution width of 26.6 cm and a high automatic feeder efficiency of 99.9%. Furthermore, the feeder used very little electricity and saved time, cost, labor, energy, and pellets.

ANALISIS PREVENTIVE MAINTENANCE MESIN AM KORIN DENGAN AGE REPLACEMENT DI PT NUGRAHA INDAH CITARASA INDONESIA

The smooth production process of PT Nugraha Indah Citarasa Indonesia is often disrupted because AM Korin machines that act for filling processes often experience damage and cause the need to repair components that are very detrimental to the company because of the time lost for production due to breakdown of these engine components, causing production loss. Preventive maintenance schedule is needed to prevent damage in the future to find out the maintenance time intervals for AM Korin engine components so as to eliminate downtime based on selection with the most minimal cost savings. Age Replacement is a preventive replacement based on the age of the component by following a certain distribution pattern. So preventive replacement is carried out by re-establishing the time interval for the next preventive replacement in accordance with a predetermined interval in the event of a replacement due to the damage that occurred. The Age Replacement method serves to accurately predict AM Korin engine component replacement activities that often suffer damage by analyzing based on historical data of damage to these components as well as knowing the optimal cost emphasis for each time interval of component replacement.The results of the study showed that one of the optimal replacement intervals was 23 days for sensor components with a replacement cost of Rp. 77. 625,000 which reduces the cost of previous treatments, which is Rp. 99,900,000. Keywords: Age Replacement; Preventive Maintenance; BreakdownAbstrakKelancaran proses produksi PT Nugraha Indah Citarasa Indonesia sering mengalami gangguan karena mesin AM Korin yang bertindak untuk proses filling sering mengalami kerusakan dan menimbulkan keperluan untuk perbaikan komponen yang sangat merugikan bagi perusahaan karena waktu yang hilang untuk produksi akibat breakdown komponen mesin tersebut sehingga menyebabkan production loss. Jadwal preventive maintenance sangat dibutuhkan untuk mencegah kerusakan di masa yang akan datang untuk mengetahui interval waktu perawatan bagi komponen mesin AM Korin sehingga dapat mengeliminasi downtime berdasarkan pemilihan dengan penghematan biaya yang paling minimal. Age Replacement merupakan penggantian pencegahan berdasarkan umur dari komponen dengan mengikuti pola distribusi tertentu. Jadi penggantian pencegahan dilakukan dengan menetapkan kembali interval waktu penggantian pencegahan berikutnya sesuai dengan interval yang telah ditentukan jika terjadi penggantian akibat kerusakan yang terjadi. Metode Age Replacement berfungsi untuk memprediksikan secara akurat kegiatan penggantian komponen mesin AM Korin yang seringkali mengalami kerusakan dengan menganalisa berdasarkan data historis kerusakan komponen tersebut serta mengetahui penekanan biaya optimal untuk setiap interval waktu penggantian komponen. Hasil dari penelitian menunjukkan bahwa salah satu selang waktu penggantian optimal yaitu selama 23 hari untuk komponen sensor dengan biaya penggantian Rp. 77. 625.000 dimana menekan biaya perawatan sebelumnya yaitu sebesar Rp. 99.900.000.

A combined methodology for the approximate estimation of the roots of the general sextic polynomial equation

In this article we present the methodology, according to which it is possible to derive approximate solutions for the roots of the general sextic polynomial equation as well as some other forms of sextic polynomial equations that normally cannot be solved by radicals; the approximate roots can be expressed in terms of polynomial coefficients. This methodology is a combination of two methods. The first part of the procedure pertains to the reduction of a general sextic equation H(x) to a depressed equation G(y), followed by the determination of solutions by radicals of G(y) which does not include a quintic term, provided that the fixed term of the equation depends on its other coefficients. The second method is a continuation of the first and pertains to the numerical correlation of the roots and the fixed term of a given sextic polynomial P(x) with the radicals and the fixed term of the sextic polynomial Q(x), where the two polynomials P(x) and Q(x) have the same coefficients except for the fixed term which might be different. From the application of the methodology presented above, the following formulation is derived; For any given general sextic polynomial equation P with coefficients within the interval [a, b], a defined polynomial equation Q corresponds which has equal coefficients to P except for its fixed term which might be different and dependent on the other coefficients so that Q has radical solutions. If we assume a pair of equations P, Q with coefficients within a predetermined interval [a, b], the numerical correlation through regression analysis of the radicals of Q, the roots of P and the fixed terms of P, Q, leads to the derivation of a mathematical model for the approximate estimation of the roots of sextic equations whose coefficients belong to the interval [a, b].

A combined methodology for the approximate estimation of the roots of the general sextic polynomial equation

In this article we present the methodology, according to which it is possible to derive approximate solutions for the roots of the general sextic polynomial equation as well as some other forms of sextic polynomial equations that normally cannot be solved by radicals; the approximate roots can be expressed in terms of polynomial coefficients. This methodology is a combination of two methods. The first part of the procedure pertains to the reduction of a general sextic equation H(x) to a depressed equation G(y), followed by the determination of solutions by radicals of G(y) which does not include a quintic term, provided that the fixed term of the equation depends on its other coefficients. The second method is a continuation of the first and pertains to the numerical correlation of the roots and the fixed term of a given sextic polynomial P(x) with the radicals and the fixed term of the sextic polynomial Q(x), where the two polynomials P(x) and Q(x) have the same coefficients except for the fixed term which might be different. From the application of the methodology presented above, the following formulation is derived; For any given general sextic polynomial equation P with coefficients within the interval [a, b], a defined polynomial equation Q corresponds which has equal coefficients to P except for its fixed term which might be different and dependent on the other coefficients so that Q has radical solutions. If we assume a pair of equations P, Q with coefficients within a predetermined interval [a, b], the numerical correlation through regression analysis of the radicals of Q, the roots of P and the fixed terms of P, Q, leads to the derivation of a mathematical model for the approximate estimation of the roots of sextic equations whose coefficients belong to the interval [a, b].

Determination of Minimum Infusion Rate and Cardiorespiratory Effects of Total Intravenous Anesthesia of Ketofol With or Without Lidocaine, Fentanyl or Dexmedetomidine in Dogs

Background: Ketofol is a 1:1 mixture of ketamine and propofol that has been proposed for induction and maintenance of anesthesia aiming to provide more cardiovascular stability and less undesirable impacts compared to the use of propofol and ketamine alone. However, it has been associated with exacerbated respiratory depression in dogs. Diminishing the dose of ketofol may improve cardiovascular effects and attenuate respiratory depression. The present study was designed to evaluate the effect of adding lidocaine, fentanyl or dexmedetomidine at the required dose and cardiorespiratory variables in dogs undergoing total intravenous anesthesia (TIVA) with ketofol. In phase I, twelve dogs were induced and maintained with two out of four anesthetic regimens of KET: ketofol (4 mg/kg and 0.3 mg/kg/min, respectively), KLD; ketofol and lidocaine (1.5 mg/kg and 0.25 mg/kg/min, respectively), KFN: ketofol and fentanyl (LD: 5 µg/kg and 0.1 µg/kg/min, respectively) and KDX: ketofol and dexmedetomidine (2 µg/kg and 2 mg/kg/h, respectively). Minimum infusion rate (MIR) of ketofol was determined in this phase. Subsequently, in phase II, other twelve dogs were given the same anesthetic regimens for 60 min similar to the previous phase, except the infusion rate of ketofol. Cardiorespiratory variables were recorded in predetermined interval. Results: In phase I, mean MIR of ketofol for KET, KLD, KFN and KDX were determined to have decreasing manner as 0.35, 0.23, 0.15, and 0.08 mg/kg/min, respectively. In phase II, the times of recovery events were shorter in KFN and KDX than KET and KLD. Notably, HR was significantly higher than baseline during anesthesia in KET and KLD, which also was significantly lower than baseline in KFN and KDX at several time points. Significant higher values of MAP were observed over time in KDX. In all treatments, there was a decrease in respiratory rate and pH as well as an increase in PCO2 during the anesthesia session. Conclusions: It was concluded that despite decreasing the dose of ketofol, none of the added drugs attenuated respiratory depression caused by ketofol.

INCREASING THE ESTIMATION EFFICIENCY OF THE FUNCTIONAL CHARACTERISTICS OF GRAIN HARVESTERS

When assessing the functional characteristics of combine harvesters, one of the most important indicators to be determined is grain loss occ urring in the threshing-and-separating unit. In compliance with GOST 28301-2015 “Combine harvesters. Test methods”, it should not exceed 1.5%. The existing methods of its determination and estimation are laborious and require specialized frames of samplers manually placed in the grain in front of the combine or the use of strip samplers. Moreover, technologies for grain harvesting with chopping and spreading straw require the use of an automated system for placing sample frames. The authors present an automatic device for placing sampling frames under the threshing-and-separating unit of a grain harvester during its operation. The proposed design fi ve sampling frames with a size of 1500×650 mm both in manual and automatic modes with a predetermined interval. The device provides for better labor safety of testers, reduces the complexity of testing by 10…15%, and improves the accuracy of the agrotechnical and operational-technological assessment of grain harvesters.

Synthesis of Robust PID Controllers by Double Optimization Method

The design of adaptive controllers allows to solve the problem of control of the object with non-stationary parameters. However, if the parameters of the object do not change too much or if only a certain interval of their change is known, it may turn out that an adaptive controller is not required, since the problem can be solved with the help of a robust controller. The robust controller allows to provide an acceptable quality of control even if the parameters of the mathematical model of the object change in some predetermined interval. A method of designing such controllers is known as the method of numerical optimization of the controllers used in the ensemble of systems in which the models of objects are different and the models of controllers are identical. The ensemble uses object models with extreme parameter values. The disadvantages of this method are too many systems that need to be modeled and optimized at the same time if there are several parameters to be changed. In addition, the worst combination of model parameters may not be boundary, but middle, in this case this method is not applicable. This article offers and analyzes an alternative method of designing a robust controller on a numerical example. The essence of this method is the numerical optimization of the regulator for the model with the worst combination of the values of all modifiable parameters. The search for the worst combination of parameters is also carried out using the method of numerical optimization. In this case, a combination of model parameters is found in which the best relation of regulator coefficients gives the worst result of the system. The problem is solved in several optimization cycles with alternating cost functions. The utility of the method is illustrated numerically by an example of a third order dynamic object with a series linked delay element.

Flora Diversity and Distribution in Falgore Game Reserve, Kano State, Nigeria

The diversity and distribution of tropical vegetation becomes more important in the face of the ever increasing threats to the tropical ecosystems. This study was carried out to examine the variations in composition and diversity characteristics of the flora species of Falgore Game Reserve in Kano State, Nigeria, with a view to promoting sustainable conservation and management of the game reserve. The study area was stratified into four topographic locations, namely: hill top, sloppy area, level ground and the riparian forest. A one kilometer line transect perpendicular to a baseline (an established tract/road) was laid in each of the four study locations. 50m × 50m sampling plots were systematically established at a predetermined interval of 200m on both sides of the transect; given a total of ten sampling plots in each study site, and a total of forty (40) plots for the study. The 50m× 50m sampling plots were used for the assessment of woody plants species (trees, saplings and shrubs). One meter squarewas used for the assessment of the herbaceous layer (Herbs and Grasses). Plant Species diversity and distribution were estimated using species richness (D), species diversity (H′) and species evenness (E). Data were analyzed using descriptive statistics and Analysis of Variance (ANOVA) at p< 0.05. A total of 3,231.2 individuals/ha distributed in 23 families, 44 genera and 53 species were recorded in the study. Thirty six (36) species (67.9%) were trees, 7 species (13.2%) were shrubs, and 10 species (18.8%) were saplings while 10 species (18%) were herbs. The highest tree species diversity (H′= 2.5) was recorded at the level ground while the least was recorded at the sloppy area, (H1= 2.1). The highest diversity for Shrubs (H1= 1.23) was recorded at the sloppy area while the least (H1 = 0.09) was recorded at the level ground. The highest species diversity of Saplings, (H′= 1.92) was recorded at the level ground while the least (H′ = 1.12) was recorded in the riparian forest. The highest mean value for tree height (14.8m) was recorded at riparian forest while the lowest (10.5m) was recorded at hill top. Findings of this study showed that land use types in association with environmental factors have substantial influences on the density and morphological characteristics of plant species in Falgore Game Reserve.

Automatic Lubrication System for Minimizing Friction of Driving Parts for Large-Sized Commercial Vehicle

One of the causes of malfunction of commercial vehicle is corrosion or wear. In order to prevent corrosion and wear, lubricants have to be supplied periodically. However, the period of lubrication usually depends on operator's judgment. If the period is too short, excess lubricant will cause pollution and unnecessary expenses, whereas long periodic supply of lubricant might cause wear, damage and eventual breakdown. Therefore, an automatic lubrication system with predetermined interval will reduce the excessive supply of lubricating oil and prevent wear and damage. This thesis presents an automatic lubrication system which consists of a lubricant pump and an embedded controller. An automatic lubrication operating algorithm is used to operate the lubricant pump and feedback the pressure status of the system using pressure sensors. The developed system shows an efficient periodic supply of lubricant.

Evaluation of the Properties of Cemented Liquid Scintillator Wastes under Flooding Scenario in Various Aqueous Media

Experiments simulating flooding scenario in various aqueous media for a long period were carried out to determine the adequacy of cement-clay composite for solidification/stabilization of spent organic radioactive liquid scintillator wastes. The final cement waste form blocks were immersed in three aqueous media, namely, seawater, groundwater, and tapwater. The immersion process lasted for increasing periods up to 540 days. Following each predetermined interval period, physical and mechanical evaluations of the immersed blocks were determined. In addition, the change in the hydration products was followed by X-ray diffraction and infrared spectroscopy as nondestructive analyses to recognize the deterioration in the microstructure that may occur due to the flooding event. Thermal analysis and scanning electron microscopy were performed to confirm the data obtained.