Feed Rate Conditions Research Articles

Effects of four factors on the quality of male reproductive cycle in pikeperch Sander lucioperca

A multiplicity of factors could modulate the quality of gametogenesis in fish. In the present study, we used a fractional factorial design (2 4-1, resolution IV) experiment to determine the possible effects and interactions between three nutritional factors both before (initial fat store: high vs low initial fat index) and during an entire reproductive cycle (food type: pellets vs forage fish, feeding rate: ad libitum vs restricted) and photoperiodic condition (simulated natural vs natural photoperiod) on both male pikeperch condition at spawning and sperm quality. The initial fat store of males appeared to be the most influential factor on the quality of sperm, in terms of the concentration of spermatozoa and motility at 15 s, and also on the timing of spermiation: fish with high initial fat store were spermiating earlier during the spawning season. A significant interaction between the initial fat store and feeding rate during fall and winter was found on the variation of weight, i.e., pikeperch changed its feeding behaviour according to the modalities of these two factors. On the opposite, feeding rate, food type and photoperiodic conditions during the experiment appeared less important. Consequently, the use of males with high initial fat store before the starting of a reproductive cycle is strongly recommended.

Picobubble Column Flotation of Fine Coal

Froth flotation is widely used in the coal industry to clean −28 mesh (0.6 mm) or −100 mesh (0.15 mm) fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range, nominally 10–100 µm, beyond which the flotation efficiency drops sharply. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. Experimental results have shown that the use of picobubbles in a 5-cm diameter column flotation increased the combustible recovery of a highly floatable coal by up to 10% and that of a poorly floatable coal by up to 40%, depending on the feed rate, collector dosage, and other flotation conditions.

Inferential Conversion and Composition Monitoring via Microcalorimetric Measurements in Emulsion Terpolymerization

Online calorimetry was used to estimate the conversion and the cumulative terpolymer composition in free radical emulsion polymerization of styrene/methyl methacrylate (MMA)/methyl acrylate (MA) within batch and semi-batch stirred tank reactors. The model includes the mass and energy balance equations over the reactor and its peripherals. Energy balance equations include the heat of reaction, internal and external heat transfer effects, as well as external heat losses. Experiments were conducted in conjunction with a reactor instrumented with platinum resistance thermal transducers and gravimetric conversion measurement devices. The experiments were conducted at variable operational conditions of feed rate, temperature and monomer feed ratios. The estimated values of conversion and terpolymer composition obtained from calorimetric data were compared with measurements of conversion and cumulative terpolymer composition by gravimetry and NMR techniques. Good agreement was observed between the inferential calorimetric estimation and corresponding process measurements. We established that online calorimetry is suitable for use as a soft sensor for the prediction of the rate of reaction, conversion and terpolymer composition.

Non-Contact Measuring Modeling and Simulation of CNC Machine Tools under High Feed Rate Condition

This article sets forth a new precision measurement method of CNC machine tools. The method incorporates the laser interferometer and the measurement principle of the double ball bar (DBB), and can measure the machine tool precision under the high feed rate condition. The generalized measurement model of three-axis has been built. Data analysis software is developed to simulate the run condition of machine tools. The repeatable experiment results proves that the method is feasible and its precision is higher than DBB`s.

Selection of optimal MQL and cutting conditions for enhancing machinability in turning of brass

Minimum quantity of lubrication (MQL) in machining is an established alternative to completely dry or flood lubricating system from the viewpoint of cost, ecology and human health issues. Hence, it is necessary to select proper MQL and cutting conditions in order to enhance machinability for a given work material. The present work aims at determining the optimum amount of MQL and the most appropriate cutting speed and feed rate during turning of brass using K10 carbide tool. Taguchi technique with the utility concept, a multi-response optimization method, has been proposed for simultaneous minimization of surface roughness and specific cutting force. The experiments were planned as per Taguchi's L 9 orthogonal array with each experiment performed under different conditions of MQL, cutting speed and feed rate. The analysis of means (ANOM) and analysis of variance (ANOVA) on multi-response signal-to-noise (S/N) ratio were employed for determining the optimal parameter levels and identifying the level of importance of the process parameters. The optimization results indicated that MQL of 200 ml/h, cutting speed of 200 m/min and a feed rate of 0.05 mm/rev is essential to simultaneously minimize surface roughness and specific cutting force.

Taguchi multiple-performance characteristics optimization in drilling of medium density fibreboard (MDF) to minimize delamination using utility concept

Abstract This paper presents the methodology of Taguchi optimization method for simultaneous minimization of delamination factor at entry and exit of the holes in drilling of SUPERPAN DECOR (melamine coating layer) MDF panel. The delamination in drilling of MDF affects the aesthetical aspect of the final product and hence it is essential to select the best combination values of the drilling process parameters to minimize it. The utility concept has been employed for the multi-performance characteristics optimization using Taguchi design. The experiments were carried out as per L 9 orthogonal array with each experiment performed under different conditions of feed rate and cutting speed. The analysis of means (ANOM) was performed to determine the optimal levels of the parameters and the analysis of variance (ANOVA) was employed to identify the level of importance of the machining parameters on delamination factor. The investigations revealed that the delamination can be effectively reduced in drilling of MDF materials by employing the higher cutting speed and lower feed rate values.

Comparison of Different Reactor Configurations for the Reduction of Free Acidity in Raw Materials for Biodiesel Production

Waste oils used in biodiesel production contain high concentrations of free fatty acids. We studied the esterification of oleic acid, dissolved in soybean oil, with methanol in order to simulate its behavior. We used sulfonic exchange acid resin as the catalyst in two different reactors: a well-stirred slurry reactor (WSSR) and a spray tower loop reactor (STLR) both working at atmospheric pressure. Methanol was fed continuously to both the reactors with very low feed rates in order to minimize the amount of methanol emerging from the reactor outlet. This methanol removed the water produced in the reaction thereby favoring esterification. The WSSR and STLR had very similar performance in that were both better than that of a plug flow reactor (PFR) working in the same conditions of atmospheric pressure and low methanol feed rate. Both the WSSR and STLR showed liquid-solid phase mass transfer limitations. All the kinetic runs have been interpreted with a mathematical model adopting the kinetics previously developed by the authors using a well-stirred batch reactor. For both the reactors, the feasibility of a pseudocontinuous operation has also been successfully tested.

Semi-continuous emulsion polymerization of styrene in the presence of poly(methyl methacrylate) seed particles. Polymerization conditions giving core–shell particles

This work reports the morphology of two-phase latex particles prepared by semi-continuous seed emulsion polymerization of styrene in the presence of polar poly(methyl methacrylate), PMMA, seed particles, using different conditions of non-polar styrene feed rate, rate of initiation, seed particle concentration and temperature of polymerization. The expected latex particle morphology at thermodynamic equilibrium is an inverted core–shell structure where the non-polar polystyrene would form the core. However, depending on the set of process conditions used the morphology of the resulting two-phase particles varied from that of a pure core–shell structure, over intermediate structures in which a shell of PS surrounded a PMMA core containing an increasing number of PS phase domains, to a structure in which the entire PS phase was present as discrete PS phase domain, more or less evenly distributed in a matrix of PMMA. By the use of a caloirimetric reactor system the monomer concentration in the particles during the different polymerization experiments could be calculated by comparing the integral of the polymerization rate curve with the integral of the monomer feed rate. A comparison between particle morphology and the calculated concentration of plasticizing monomer in the polymerizing particles strongly suggested that the diffusivity of the entering oligo radicals determined by the difference between polymerization temperature and the glass transition temperature of the monomer-swollen core polymer is a key factor determining the morphology of two-phase particles prepared by semi-continuous seed emulsion polymerization. Two-phase particles with a true core–shell structure were obtained in experiments where the estimated glass transition temperature of the PMMA phase was only a few degrees below the polymerization temperature. The results show that such particles can be obtained under conditions of high as well as low styrene feed rates, provided that the rate of initiation is properly adjusted.

4220 高速マイクロスピンドルを用いた旋削(J24-2 生産機械のマイクロ化(2))

In order to clarify the behavior under micro cutting conditions, we have performed cutting of aluminum alloy and free machining brass using the high-speed micro-spindle. The results of the experiment shows that surface roughness has been improved under the conditions of high rotation speed and low feed rate. These conditions mean that an area of chip section is small. Cutting resistance force increases in proportion to the-increase in an area of chip section, although dispersion is large. These results indicate that the specific cutting force becomes remarkably large when an area of chip section becomes small at high rotation speed.

Electrospinning of Poly (ether sulfone) and Evaluation of the Filtration Efficiency

To produce high heat-resistant air filter, filtration properties of poly (ether sulfone) (PES) made by various electrospinning conditions were evaluated. The PES webs of 0.4-1.1 um average diameter fiber were obtained from 35-40 wt% PES / N,N- Dimethylacetamide (DMAc) solution. The diameter profile of electrospun PES web was clearly affected by PES concentration of the spinning dope and feeding rate of the dope, while the take-up speed effects little. The needle-collector distance affects the diameter profile for higher feeding rate conditions. The pore size of these webs was 1.3 - 5.6 um, which was decided not only average fiber diameter but also fiber diameter variation. Both filtration efficiency and pressure loss were dropped steeply at about 3.0 um of pore size. For the web having a pore size of 3.2 um, the pressure loss decrease to 215 Pa, while the filtration efficiency for 0.3 μm particle kept 99.9998 %, which satisfied the HEPA requirement.

Picobubble Enhanced Fine Coal Flotation

Froth flotation is widely used in the coal industry to clean −28 mesh fine coal. A successful recovery of particles by flotation depends on efficient particle‐bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range beyond which the flotation efficiency drops drastically. It is now known that the low flotation recovery of particles in the finest size fractions is mainly due to a low probability of bubble‐particle collision while the main reason for poor coarse particle flotation recovery is the high probability of detachment. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles in a wide range of size by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. They are characterized by a size distribution that is mostly below 1 µm and adhere preferentially to the hydrophobic surfaces. The presence of picobubbles increases the probability of collision and attachment and decreases the probability of detachment, thus enhancing flotation recovery. Experimental results with the Coalberg seam coal in West Virginia, U.S.A. have shown that the use of picobubbles in a 2″ column flotation increased fine coal recovery by 10–30%, depending on the feed rate, collector dosage, and other flotation conditions. Picobubbles also acted as a secondary collector and reduced the collector dosage by one third to one half.

Study on High Speed Cutting of Bio-Titanium alloy

Using a binder-less PcBN tool, the influences of cutting speed on tool life and wear pattern in turning of Ti-6Al-2Nb-1Ta, which was a vanadium free titanium alloy for a surgical implant material, were investigated. In the condition of feed rate of 0.15mm/rev and depth of cut of 0.5mm with an application of a high pressure coolant, the tool life at cutting speed of 4.2m/s was the longest in the various cutting speeds. In conditions of cutting speed of below 4.2m/s the tool life was determined by chipping and flaking occurring on tool face, on the other hand, smooth wear on the tool face were observed in over 4.2m/s. And, it was confirmed that the smooth wear on the tool face in turning process appeared over 730°C of tool flank temperature , and the promotion of tool wear was so dependent on the cutting temperature. Also, in order to investigate this reaction in the cutting process, the experimental model reaction test between the tool material and the workpiece one by using the SPS equipment were conducted in addition to element analysis of the adhesive on the cutting edge using EDS and XRD. As a result, it was clarified that TiB2 was generated in the interface between the binder-less PcBN and the titanium alloy, and the reaction was sensitive to its temperature.

411 りん青銅の超精密切削仕上面における結晶粒界段差(OS-13 先端材料・難削材の加工)

This paper deals with the step generated at the grain boundary in an ultra-precision diamond cutting of phosphor bronze for a typical metal mold of Fresnel lens. In this study, the cutting experiments were carried out with an ultra-precision cutting machine by a single crystal diamond tool in order to investigate the relationship between the generation of grain boundary step and the cutting conditions. The influence of the thrust force component and the heat treatment on the step at grain boundary is discussed. It was found that the thrust component of the cutting force and the feed rate condition greatly influence the magnitude of the step at grain boundary.

Rational strategy for the production of new crude lipases from Candida rugosa

Candida rugosa was cultured using different inducers (oleic acid, olive oil, sunflower oil, n-dodecanol and glycerol) as the only carbon source in batch conditions, as well as in several fed-batch fermentations (oleic acid as inducer) at variable feed rate conditions. The N-terminal analysis of each crude lipase revealed that, while the isoenzymes Lip2 and Lip3 are always secreted (at different proportions depending on the inducer), Lip1 was produced only using n-dodecanol (batch conditions) or oleic acid (fed-batch at high feed rate). The nature of the inducer controls the isoenzyme percentage; when this is fixed, as well as the feed rate in fed-batch fermentation, the isoenzymatic profile remained unaltered and the samples differed only in the activity of the lipases, as determined by heptyl oleate synthesis.

The effects of chamfered and honed tool edge geometry in machining of three aluminum alloys

The effects of tool edge geometry in machining have received much attention in recent years due to a variety of emerging machining techniques, such as finish hard turning and micro-machining. In these techniques, the uncut chip thickness is often on the same order of magnitude as tool edge dimension. This paper presents and analyses the results of our recent experimental and theoretical study on the effects of tool edge geometry in machining. Both chamfered and honed tools are investigated covering a wide range of cutting speed and feed rate conditions. The three aluminum alloys 7075-T6, 6061-T6, and 2024-T351 are selected as work materials for particular research purposes. The cutting force, the thrust force, the ratio of the cutting force to the thrust force, and the chip thickness are measured. The similarities and differences in machining with a chamfered tool and with a honed tool are compared. A new slip-line model of chip formation for machining with a chamfered tool is proposed. Good agreement has been reached between the predicted and experimental results. The effects of different aluminum alloys and cutting speeds on the cutting forces, especially on the thrust force, are also studied.

In-Flight Spheroidization of Alumina Powders in Ar?H2 and Ar?N2 Induction Plasmas

In-flight spheroidization of alumina powders in Ar–H2 (H2–7.6%, vol/vol) and Ar–N2 (N2–13.0%, vol/vol) RF induction plasmas was investigated numerically and experimentally. The mathematical model for the plasma flows incorporates the k–ɛ turbulence model, and that for particles is the Particle-Source-in-Cell (PSI-Cell) model. Experimental results demonstrate that spheroidized alumina particles are produced in both Ar–H2 and Ar–N2 RF plasmas, with different particle size distributions and crystal phases. Agreement between the predicted and measured particle size distributions is satisfactory under high particle feed rate conditions, while the results obtained for the Ar–H2 plasma are better than those for the Ar–N2 plasma. The discrepancy occurring in low feed rate conditions suggests that particle evaporation is an important factor affecting the plasma–particle heat transfer.

A Stick Motion Compensation System with a Dynamic Model

This paper deals with a stick motion compensation system. Stick motion is trajectory error that happens just after a quadrant change in circular motion on NC machine tools. Recently cylindrical machining with an end mill is often executed instead of boring machining with a bore tool. That is why the accuracy with end mill machining is becoming important. Stick motion extremely damages the accuracy and the quality of the circular parts or free form surfaces on workpieces. In the conventional compensation system, tuning parameters for each combination of radius and feed rate is needed. This research proposes a new stick motion compensation system. The new system has a dynamic model that simulates the friction. The simulated friction consists of two components. One is spring resistance in proportion to a reverse distance from a quadrant change. The other is viscous damping friction in proportion to velocity. The system can compensate stick motions suitably for wide range conditions of radii and feed rate.

320 A Stick Motion Compensation System with a Dynamic Model

This paper deals with a stick motion compensation system. Stick motion damages extremely the accuracy and the quality of workpieces in circular motions or on free form surfaces. In the conventional compensation system, it needed to tune parameters for each combination of radius and feed rate. This research proposes a new stick motion compensation system. The new system has a dynamic model that simulates the friction. The simulated friction consists of two components. One is spring resistance in proportion to a reverse distance from a quadrant change. The other is viscous damping friction in proportion to velocity. The system can compensate stick motions suitably for wide range conditions of radii and feed rate.

焼入鋼のエンドミル加工に関する研究 ２ 工具経路の移行部を含む曲線切削時の切削抵抗の一定化制御

In this paper, the proposed model for cutting forces during end milling of hardened steel is verified for its general usefulness by applying this model to the extended cutting conditions and other applications. The cutting conditions discussed here include concave contour cuttings with a small radius compared to that of the end mill. For this purpose, the operability region by two variables of the arc length of cutting engagement (L) and the maximum undeformed chip thickness(tm) is divided into a few regions of interest which correspond to the cutting conditions geometrically. The control of cutting forces in profile end milling using quadratic polynomials obtained in each region based on response surface methodology was fairly effective. Furthermore, this prediction model was applied for the case of transitional sections of tool paths where the cutting force changes rapidly with the change of feed rate and geometrical conditions, and it was found that the prediction and control of cutting forces was also possible for this problem.

Experimental Study on the Spray Characteristics in the Spray Drying Absorber

A pilot-scale spray drying absorber (SDA) system was set up to evaluate the effect of spray characteristics on flue gas desulfurization efficiency. Varying spray injection conditions and inlet gas conditions, SO2 concentrations were measured using a combustion gas analyzer. As a reagent, a slaked lime (Ca(OH)2) slurry was treated with flue gas containing SO2. The influence of each parameter is determined by the compromise between the droplet absorption capability and SO2 gas supply to the region of the droplet cloud. When the SO2 molecules are sufficiently supplied to the wet droplet surface, the variation of the total droplet surface area plays a dominant role in the desulfurization process. The conditions of low inlet gas temperature and low slurry feed rate are included in this case. However, when the droplets of sprayed slurries are too small or evaporation proceeds too fast, the SO2 molecules cannot be sufficiently transferred to the droplet surface. The excess calcium sorbents in the droplets dry out before they react with the hot gas. Consequently, the desulfurization efficiency as well as the utilization efficiency of Ca decreases for the smaller droplets. This trend appears to be dominant in conditions of high gas temperature and large slurry feed rate with the small Sauter mean diameter (SMD) of spray droplets. From the experimental results, we proposed two empirical models for the desulfurization efficiency and operating conditions.