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.

Leaching of Rare Earth Elements from NdFeB Magnets without Mechanical Pretreatment by Sulfuric (H2SO4) and Hydrochloric (HCl) Acids

A simplified approach for rare earth elements leaching from NdFeB (neodymium-iron-boron) magnets was investigated. The possibility of simplifying the magnet recycling process by excluding grinding, milling and oxidative roasting unit operations was studied. Attempts to skip the demagnetization step were also conducted by using whole, non-demagnetized magnets in the leaching process. The presented experiments were conducted to optimize the operating conditions with respect to the leaching agent and its concentration, leaching time, leaching temperature and the form of the feed material. The use of hydrochloric and sulfuric acids as the leaching agents allowed selective leaching of NdFeB magnets to be achieved while leaving nickel, which is covering the magnets, in a solid state. The application of higher leaching temperatures (40 and 60 °C for sulfuric acid and 40 °C for hydrochloric acid) allowed us to shorten the leaching times. When using broken demagnetized magnets as the feed material, the resulting rare earth ion concentrations in the obtained solutions were significantly higher compared to using whole, non-demagnetized magnets.

Theoretical analysis of the factors, influencing composition uniformity of the cadmium zinc telluride substrates grown by THM

The effect of the sample composition, variation of the temperature field and the feed material non-homogeneity on uniformity of the growing crystal is considered. It is shown that optimization of the solvent composition makes it possible to minimize the jump of the ZnTe concentration at the seed/crystal boundary. The composition fluctuations at variation of the thermal field during crystal growth are smooth enough and relatively non-significant. The feed composition distribution has, as a rule, a random character. Different harmonics of composition distribution non-uniformity in the feed material differently affect the homogeneity of the growing crystal. Longwave non-uniformities in the feed transform into the growing crystal almost completely. At the wavelength equals to a half of the solvent length or shorter, the perturbations of the growing crystal composition are relatively small. Evidently, the cause of the local composition variations, found in real crystals, is, basically, the feed composition non-uniformities

Italian Consumers’ Readiness to Adopt Eggs from Insect-Fed Hens

Demand for eggs from laying hens is increasing as the world population continues to grow. The use of insects as animal feed is a strategic opportunity to find a new innovative, economic and sustainable source of protein. The aim of this study was to evaluate the Italian consumer inclination for eggs produced with the use of insect-fed hens. The investigation on consumers’ readiness to adopt eggs from insect-fed hens was carried out through an online survey conducted on 510 participants. Survey results outlined four different clusters on the basis of the willingness to buy/eat eggs fed with insects: “ready” (40.1%), “environmentalist” (24.3%), “cautious” (21.7%), and “reluctant” (13.9%). “Ready”, “environmentalist”, and “cautious” were quite favorable to the use of insects as feed stuffs and share drivers for product choice: cheap, organic, and with an explicit indication of use of insects. On the other hand, for the “reluctant”, the diet based on insects was the main negative factor influencing product acceptance. This cluster also showed the highest level of neophobia. Italian consumers showed a considerable level of readiness to accept insects as feed material for egg production, which should be reinforced with further information on the origin and the environmental benefit of using insects.

Processing Dross from Hot-Dip Galvanizing by Chlorination Roasting

Dross from hot-dip galvanizing is an important source of pure zinc ingots and zinc oxide for use as mineral additives in animal and poultry feed. Thermodynamic calculations have shown the possibility of solving the issue of dross processing by roasting using CaCl2 and NH4Cl. The influence of the consumption of chlorinating reagents, the roasting temperature on the degree of sublimation of Pb, Fe, Ni, Cu and Cd has been investigated. It has been shown that the best results are achieved when roasting the dross with the simultaneous use of CaCl2 and NH4Cl in amounts of 6 and 15% by weight of the feed material. The optimal roasting parameters were established: T = 1000 °C, duration—60 min, air flow—0.1 L/min. Recovered pure zinc oxide composition (%) was: 0.05 Pb, 0.15 Fe, 0.06 Ni, 0.003 Cu and 0.001 Cd. The degree of sublimation of copper, nickel and iron chlorides was ~75%, with lead and cadmium at 90–98% of their initial amount in the dross.

In Vitro Digesting Measurement of Cassava Leaves Using Gizzard Fluid and Chicken Duodenum

Cassava leaves are an alternative feed material that can be a feed material with sufficient protein content. The study aimed to determine the effect of gizzard and duodenal fluids on in vitro digesting measurements of cassava leaves. The study used a Complete Randomized Design (RAL) unidirectional pattern, Variance Analysis (ANOVA) with Duncan's Multiple Range Terst (DMRT) follow-up test using the SPSS application. The study used 4 treatments and 3 repeats: P0: No digestive fluids (controls), P1: Gizzard fluid, P2: Duodenal fluid, P3: A mixture of gizzard and duodenal fluids. The observed variables are the Dry Material Digest Coefficient (KCBK), the Organic Material Digest Coefficient (KCBO), and the Dissolved Protein Digest Coefficient (KCPT). The results of the study that the use of gizzard fluid in in vitro digestion measurements was better in increasing the value of in vitro digestant of cassava leaves. The use of gizzard fluid can increase the digestibility coefficient of organic matter (KCBO) by 21.2160% and the dissolved protein digest coefficient (KCPT) by 50.4620%.

CATALYST PROCESSING AND RECYCLING

Discussed auto catalysts contain interesting quantities of platinum noble metals, palladium and rhodium according to the type of auto catalyst, thereby becoming a possible source of these metal aims to acquaint themselves with catalysts in general, their history and last but not least the possibilities of processing and obtaining noble metals for further use. The article deals with knowledge at the theoretical level of use of methods in processing depleted catalysts. It is pyrometallurgical and hydrometallurgical methods. The platinum group metals (PGMs) palladium, platinum, and rhodium represent the key materials for automotive exhaust gas treatment. Since there are currently no adequate alternatives, the importance of these metals for the automotive industry is steadily rising. The high value of PGMs in spent catalysts justifies their recycling. The state-of the-art technology is to melt the ceramic carrier and collect the precious fraction in a liquid metal bath. As the feed material has quite high melting points, huge amounts of energy are required for this process. Hydrometallurgical treatments of the spent catalysts offer the possibility to recycle the PGMs with less energy and time demands. Moreover, automotive catalysts contain further valuable materials to improve the exhaust gas treatment. These compounds, like cerium oxide, cannot be recovered in pyrometallurgical processes.

Ultra-Fine Centrifugal Concentration of Bastnaesite Ore

Historically, the ability to effectively separate carbonate gangue from bastnaesite via flotation has frequently proven to be challenging without sacrificing significant rare earth oxide (REO) grade or recovery. However, in light of the fact that the rare earth bearing minerals often exhibit higher specific gravities than the carbonate gangue, the possibility exists that the use of gravity separation could be used to achieve such a selective separation. This however is complicated by the fact that, in cases such as this study when the liberation size is finer than 50 µm, most traditional gravity separation methods become increasingly challenging. The purposes of this study is to determine the applicability of gravity concentrators to beneficiate bastnaesite from deleterious calcite bearing flotation feed material. Via the use of a UF Falcon, it was possible to achieve rougher gravity REO recoveries approaching the upper 80% range while rejecting on the order of 30% of the total calcium. In terms of purely REO recovery, this represents a significant improvement over results obtained via a traditional Falcon in previously reported studies.

Anaerobic Biodegradation of Wheat Straw Lignin: The Influence of Wet Explosion Pretreatment

Large amounts of lignin residue is expected in the future when biorefineries for producing biofuels and bio-products will increase in numbers. It is, therefore, valuable to find solutions for using this resource for the sustained production of useful bioenergy or bio-products. Anaerobic digestion could potentially be an option for converting the biorefinery lignin into a valuable energy product. However, lignin is recalcitrant to biodegradation under anaerobic conditions unless the structure is modified. Wet oxidation followed by steam explosion (wet explosion) was previously found to make significant changes to the lignin structure allowing for biodegradation under anaerobic conditions. In this study, we examine the effect of wet explosion pretreatment for anaerobic digestion of wheat straw lignin under mesophilic (37 o C) conditions. Besides the biorefinery lignin produced from wheat straw, untreated lignin was further tested as feed material for anaerobic digestion. Our results showed that wet exploded lignin pretreated with 2% NaOH showed the highest lignin degradation (41.8%) as well as the highest methane potential of 157.3±9.9 ml/g VS. The untreated lignin with no pretreatment showed the lowest methane yield of 65.8±4.8 and only 3.5% of the lignin was degraded. Overall, increased severity of the pretreatment was found to enhance anaerobic degradation of lignin.