Drum Speed Research Articles

Tuning Fiber Alignment to Achieve Mechanical Anisotropy on Polymeric Electrospun Scaffolds for Cardiovascular Tissue Engineering

Background: Soft tissues are characterized by strong mechanical anisotropy, as a result of internal fiber architecture, matching the needs of mechanical function in each body part. Polymeric grafts, used for diseased tissues replacement, suffer from mechanical mismatch with the tissues replaced and the remaining healthy tissues to be connected. Electrospinning is an attractive technique by which we can produce biodegradable polymeric scaffolds for tissue engineering applications. Fiber characteristics and structural architecture has to be tuned to match mechanically the tissues to be replaced. Furthermore, for the design of fibrous scaffolds, other characteristics, like fiber diameter, porosity and hydrophilicity play an important role as far as cell atraction, function and tissue regeneration are concerned.Objective: In the present work, we aimed to produce polymeric membranous scaffolds with specific architecture, giving attention to fibers’ orientation and hence, controlling the final mechanical behavior to match that of the physiological tissues to be replaced.Methods: To this end, we used a specifically designed drum collector, with accurate velocity control, and tested different electrospinning parameters (polymeric solution concentrations, transfer rates, rotational speed, etc) to obtain design optimization.Results: Scanning Electron Microscopy on scaffolds showed a good morphology quality. Fiber orientation was directly related to the drum speed. Tensile testing showed mechanical anisotropy in higher speeds. Young’s modulus and Ultimate tensile strength demonstrated strong anisotropy (one order of magnitude larger) in parallel to transverse direction, with regard to drum speed, similar to that of physiologic soft cardiovascular tissues. Scaffold hydrophilicity, expressed by contact angle measurements remained high, although a relation to fiber architecture has been recorded. Conclusion: Enhancement of membranous anisotropy was attained, one order of magnitude greater for the parallel fibers’ direction compared to the transverse one. A similar anisotropy can be found in cardiovascular soft tissues, like human and porcine aortic heart valve leaflets.

Triboelectrostatic separation of polypropylene, polyurethane, and polyvinylchloride used in passenger vehicles

Recycling and reuse of automotive plastics have elicited global attention due to the increasing number of end-of-life vehicles. Through the single-factor experiment, a high-voltage triboelectrostatic sorting device was developed to separate polypropylene (PP), polyurethane (PU), and polyvinylchloride (PVC) in a plastic mixture commonly used in exterior and interior parts of passenger vehicles. Products of PP, PU, and PVC were obtained after two-stage separation; their purity exceeded 95%, and their productivities were 74%, 94%, and 41%, respectively. The appropriate experimental parameters for high voltage level and rotational speed of the friction drum and cylinder electrode for the first stage of separation were 35 kV, 30 rpm, and 35 rpm, respectively, and the parameters for the second stage of separation were 35 kV, 30 rpm, and 25 rpm, respectively. Results showed that hybrid materials should be selected based on the triboelectric series to separate three-component plastic mixtures feasibly.

High‐speed displays encoding motor skill trigger elevated territorial aggression in downy woodpeckers

Abstract Many species perform social displays that incorporate complex body movements. However, the reason why such exaggerated behavioural signals evolve in the first place is unclear. Recent work posits that physical displays arise in part because they showcase an animal's motor skill—that is, the ability to produce challenging motor acts with great coordination, precision and/or speed. Support for this idea is largely correlational, with few studies attempting to manipulate metrics of motor skill to assess their effect on physical display efficacy. Here, we address this issue in the downy woodpecker (Dryobates pubescens). Individuals of this species compete for territories through the performance of drums, which are complex displays produced by rapidly hammering the bill against a resonate surface at rates of 16 hits/s. This display is a whole‐body endeavour, and its production relies on the ability to swiftly oscillate the head forward and backward at fraction‐of‐a‐second periods. Using a series of playback studies, we expose resident birds to experimentally engineered drums that reflect putative fine‐scale differences in the motor command of the head and neck. We show that resident individuals respond more aggressively to drums characterized by a cadence with a 9‐ms faster beat speed. These residents even modulate their own drum speed to resemble this high‐performance stimulus, although they often fail to reach it. Residents also appear to appraise drum acceleration by listening to the time intervals between successive beats in a single drum, while tracking how these time intervals change as the signal progresses. Our data support a connection between motor skill and the effectiveness of a physical display produced through elaborate body movement. We, therefore, suspect that motor skill is adaptive and evolves in response to selection by competition for effective drum displays. A plain language summary is available for this article.

Influence of process parameters on the tensile properties of DREF-3000 friction spun hybrid yarns consisting of waste staple carbon fiber for thermoplastic composites

Due to their excellent strength, rigidity, and damping properties, as well as low weight, carbon fiber reinforced composites (CFRCs) are being widely used for load bearing structures. On the other hand, with an increased demand and usage of CFRCs, effective methods to re-use waste carbon fiber (CF) materials, which are recoverable either from process scraps or from end-of-life components, are attracting increased attention. In this paper, hybrid yarns consisting of waste staple CF (40 and 60 mm) and polyamide 6 staple fibers (60 mm) are manufactured on a DREF-3000 friction spinning machine with various process parameters, such as spinning drum speed, suction air pressure, and core–sheath ratio. The relationship between different textile physical properties of the hybrid yarns, such as tensile strength, elongation, and evenness with different spinning parameters, core–sheath ratio, and input CF length is revealed.

PERFORMANCE EVALUATION OF A LOCALLY MACHINE FOR CHOPPING OF ONION RESIDUES

Crops residues are oneof themostcritical problems, which face the Egyptian farmer especially after harvesting process. The present study was carried out to evaluate of the performance efficiency of stationary threshing and separating machine of wheat crop (locally manufactured); this machine was used to cutting and chopping of onion crop residues (leafs) with the desired cutting lengths for different uses. The used machine was tested and evaluated at chopping drum speeds of 350, 450, 550 and 650 rpmand feeding rates5, 10, 15 and 20 kg/minwith two moisture contents of 11.5 and 17.6 % under air speed of 6 m/s. The results showed that; the stationary thresher machine can be successfully used for cutting and chopping of onion leafs under the following optimum conditions: 650 rpm for drum speed, 20 kg/min for feeding rate and the percentages of cutting length (less than 30 mm) were 42 and 23 % for two tested moisture contents of 17.6 and 11.5 %, respectively, also; the power consumption and specific energy requirement were found to be (14.1 and 23.9 kW) and (12.5 and 21.5 kW.h /Mg) for two tested moisture contents of 17.6 and 11.5 %, respectively. In addition to; analysis of onion leafs samples with two tested moisture contents of 17.6 and 11.5% showed that the protein contents were 10.85 and 9.97 % and fat contents were 1.75 and 6.19 %, respectively. The maximum operation costs were 86.28 LE/h and 76.48 LE /Mg.

Properties of CF/PA6 friction spun hybrid yarns for textile reinforced thermoplastic composites

Due to their excellent strength, rigidity and damping properties as well as low weight, carbon fibre reinforced composites (CFRC) are widely being used for load bearing structures. On the other hand, with an increased demand und usage of CFRCs, effective methods to re-use waste carbon fibre (CF) materials, which are recoverable either from the process scraps or from the end-of-life components are attracting increased attention. In this paper, hybrid yarns consisting of staple CF and polyamide 6 (PA 6) are manufactured on a DREF-3000 friction spinning machine with various machine parameters such as spinning drum speed and suction air pressure. The relationship between different textile physical properties of the hybrid yarns, such as tensile strength and elongation with different spinning parameters and CF content of hybrid yarn is investigated. Furthermore, the tensile properties of uni-directional (UD) composites manufactured from the developed hybrid yarn shows 80% of the UD composite strength made from CF filament yarn.

Design and Development of Manually Operated Sapota Cleaner

Cleaning of sapota is an important unit operation after harvesting. Harvested fruits are presently cleaned by manually rubbing with cloth. A manually operated sapota cleaner was designed and developed to reduce human drudgery. The cleaner was tested at 60, 65 and 70 rpm, and its batch capacity varied from 15 to 45 kg. The drum with jute cloth inner lining had cleaning efficiency of 99.95 % at 70 rpm rotational speed and 20 kg sapota batch load. At drum speed of 60 rpm and 20 or 30 kg of sapota load, no damage of fruit was observed. The cleaner gave best performance at 70 rpm drum speed, 20 kg feed /batch, giving 99.95 % cleaning efficiency and 2.04 % fruit damage. The cost of the cleaner was ` 7000, with cost saving of ` 0.30/kg sapota as compared to traditional cleaning method.

The Pre-attentive Processing under Background of Industrial Automatic Control: Evidence from the vMMN

Safety education is a kind of effective means by which people can improve safety consciousness, can master the safety theory, regulations and technology standard.The most important reason of work-safety accident is human factor and the level of safety behaviors and emergency capability of production people is the focus of human factors. From the cognitive perspective, the article analyzes the pre-attentive processing features of human under the industrial auto-control background through people’s information processing. Therefore article propose a cognitive neural experiment approach based HCI. Article used the auto-control interface of the towing vessels of ocean engineering vessels to simulate that of the real operating room. The figures on the central interface presented that the regular winding drum speed of the towing machine was 7.5m/min and the graphic symbols on the both sides of the interface presented the system pressure safety alerting signals of the towing machine. Normally, the safety alerting signals on the two sides of the interface were green rectangles, but abnormally they would be red vertical rectangles, red horizontal rectangles or red hexagons. Namely, the task-related stimuli appeared in the center of people’s view but the task-unrelated stimuli appeared on the sides. The subjects were informed to concentrate on the winding drum speed on the center of the interface and ignore the pressure safety alerting signals on the sides. If the winding drum speed changes, the subjects should react as soon as possible. The experiment adopted Oddball and Equiprobable paradigms, using Event-related Potential (ERP) technology to verify. The results show that all of the 3 kinds of safety alerting signals can cause Visual Mismatch Negativity (vMMN) negative wave but the strength values are different. The pressure safety alerting signals of red horizontal rectangle are easier to cause the operator’s attention.

Electromechanical dynamic analysis for the cutting transmission system of the unmanned long-wall shearer under variable speed process

The drum shearer is one of the main equipments of the long-wall mining system. A typical condition to adjust the hauling and drum speeds is when the drum load exceeds the allowable value due to the hardness increase of the coal seam. Two schemes are utilized in this condition herein: (1) increasing the drum speed directly and maintaining the hauling speed; (2) decreasing the hauling speed firstly, then increasing the drum speed, finally increasing the hauling speed to the original value. The electromechanical dynamic model is firstly constructed for the Cutting Transmission System, and then the electromechanical dynamic analysis is conducted with both schemes, discovering that: the first scheme is quicker but may bring instability; the second is stable but slower; the resonance in frequencies obtained in different meshing conditions can be excited at the same time. At last, some advices are given for the development of the speed control strategies and mechanical design of the unmanned long-wall shearer.

Comparative evaluation of mechanised and manual threshing options for Amankwatia and AGRA rice varieties in Ghana

Performance of a Yanmar DB 1000 mechanised paddy thresher was comparatively assessed against manual threshing by impact method using a locally-made wooden box for Amankwatia and AGRA rice varieties under farmer’s field conditions at Nobewam in the Ashanti Region of Ghana. The mechanised thresher was evaluated at various threshing drum speeds (550 rpm, 600 rpm and 650 rpm) and feeding rates (200 kgh-1, 400 kgh-1 and 600 kgh-1). Results showed that threshing was satisfactory at grain moisture content between 16.9% w.b and 18.0% w.b. for both rice varieties. Threshing efficiency increased from 94.6% to 95.8% with no significant difference observed whereas cleaning efficiency decreased significantly from 84.2 % to 81.6 % with increasing feed rate irrespective of rice variety. Again, threshing efficiency increased with increasing drum rotational speed, irrespective of feed rate and rice variety. Percentage broken grain and grain loss both increased with increasing peripheral drum speed and paddy feed rate irrespective of rice variety. Average fuel consumption, physical energy requirement and threshing capacity increased significantly with increasing drum speed and feed rate. Crop moisture content and shattering ability influenced the threshing efficiency, threshing capacity, grain loss, broken grain, fuel and physical energy requirement at threshing. AGRA rice variety generally performed better than Amankwatia under both mechanical and manually threshing methods. Mechanised threshing was significantly better at reducing grain loss and physical energy demand whilst yielding over 200% higher threshing capacity than manual threshing by impact using the wooden box. Mechanised threshing was financially rewarding, yielding over 500% higher profit margin than the manual threshing option. Further research on optimum crop moisture content for improved threshing of different rice varieties is suggested.

EVALUATION OF LOCAL MACHINE PERFORMANCE FOR FABA BEAN CURSHING

The main objective of this work was to performance evaluate for locally made small machine for faba bean crushing at moisture content of 9.5 % db. The performance of faba bean crushing machine was evaluated at different hammer drum speeds ( 1000, 1250, 1500 and 1750 r.p.m ), feeding rates ( 60, 90 and 120 kg / h ) and sieves holes diameter (2, 4 and 6 mm),were evaluated on the basis of curshing productivity (Mg/h), efficiency machine (%), total energy consumed (kW. h /Mg), Faba bean mean particle size % . The results indicated that the highest productivity was 118 kg/h and productivity efficiency 99 % obtained at 1750 r.p.m hammer drum speed , 6 mm sieves holes diameter and 120 kg / h feeding rate. The best result for crushed faba bean particle size was obtained at 1750 rpm, 2 mm sieves holes diameter and 60 kg/h feeding rate. While the minimum specific energy 7.50 kW.h /Mg was obtained at 1750 rpm, 6 mm sieves holes diameter and 120 kg / h feeding rate.

Grouping of various stains to develop programs for a front-loading washer

Stains from foodstuffs, cosmetics, and daily activities are frequently founded on our clothes. It is very annoying to remove stains, because extra treatment should be done before or after washing. A smart washing machine, which can operate adequately according to the types of stains on garments, will provide another convenience to users. In this study, the relative contributions of washing factors to the removal of stains depending on the type of stain and fiber, were investigated using domestic front-loading washers. The investigated washing factors were temperature, time, drum speed, and the ratio of motion time to pause time. Removal of 15 types of common stains on three types of cloths, such as cotton, polyester and cotton/polyester blend, was assessed. Stains were categorized by the origin: food, cosmetics, body, outdoor activities and factory work. Multiple regression equations containing interaction effects were obtained from the soiled cloths with these stains. Depending on the magnitudes of standardized regression coefficients for the effect of washing factors on the soil removal, the soiled cloths were divided into five groups: cloths soiled with oily materials, cotton cloths soiled with proteins, cloths soiled with insoluble particles, cloths soiled with highly unsaturated oils, and polyester cloths. Effective washing conditions for each group were suggested.

MANUFACTURING AND EVALUATION OF PROTOTYPE FOR MELON SEED EXTRACTION

Manual extraction process of melon seed is the most-used method in Egypt and requires large number of labors. In addition to high cost associated with the manual extraction. So, this research therefore developed locally manufactured prototype to mechanically extract seeds from melon with lower cost and higher productivity. The manufactured prototype consists of frame, feeding hopper, crushing and extracting unit, peels outlet, conveying auger of seeds, cleaning brushes and seeds outlet. Proposed prototype was tested and evaluated at Eletad village and Rice Mechanization Center (RMC), Agricultural Mechanization Research Institute, Ministry of Agriculture (Meet El Dyba, Kafr El-Sheikh governorate) during the year of 2015. The prototype evaluation done based on cleaning efficiency, extraction efficiency, machine productivity, power consumed, seed damaged and operational cost. Prototype evaluation was done at four different feeding rates (20, 30, 40 and 50 kg/min), five drum speeds (3.25, 5.47, 6.98, 8.52 and 10.64 m/s) and four time spans (0, 3, 6 and 9 days). The results showed that the increase in crushing drum speed, melon seed time span and decreasing feed rate tend to decrease the cleaning efficiency, where the highest value of cleaning efficiency was 88.83 % at crushing drum speed of 10.64 m/s, feed rate of 20 kg/min and melon seed time span 9 days after harvesting. Also, the decrease of crushing drum speed, melon seed feed rate and increasing melon seed time span tend to increasing extraction efficiency, where the maximum value of extraction efficiency was 98.85 % at crushing drum speed of 3.25 m/s, feed rate of 20 kg/min and melon seed time span 9 day. Machine productivity increased by increasing feed rate, melon seed time span and decreasing crushing drum speed, where maximum value of machine productivity was 152.14 kg/h at crushing drum speed of 3.25 m/s, feed rate of 50 kg/min and melon seed time span 9 day. Power consumption increased by increasing crushing drum speed, melon seed feed rate and melon seed time span, where the minimum value of power consumption was to 2.61 kW at crushing drum speed of 3.25 m/s, feed rate of 50 kg/min and melon seed time span 9 day. Total costs increased by increasing crushing drum speed and decreasing both melon feed rate and melon seed time span, where the minimum value of total cost was 0.273 LE/kg at crushing drum speed of 3.25 m/s, melon seed feed rate of 50 kg/min and melon seed time span 9 day.

MANUFACTURE AND EVALUATION OF A SIMPLE PROTOTYPE OF PEANUT SHELLER

A power-operated peanut sheller was manufactured and the performance was evaluated under different operational conditions. The experiments were conducted at drum rotary speeds of 150, 200, 250 and 300 rpm (2.0, 2.67, 3.33 and 4 m/s.), feeding rates of 170, 210 and 250 kg/h and air speeds of 4.9, 6.8 and 8.8 m/s. The performance was evaluated in terms of output seed damage, shelling losses, undamaged seeds, un-shelling pods, shelling efficiency and machine productivity as well as cleaning ratio. The lowest seeds damaged and shelling losses of 2.45 and 1.32% while the highest undamaged seeds and shelling efficiency of 97.55 and 96.23% were obtained at drum speed of 150 rpm (2.0 m/s) and feeding rate of 170 kg/h. The highest machine productivity of 250 kg/h was obtained at drum speed of 300 rpm (4m/s.) and feeding rate of 250 kg/h. The highestcleaning ratio 98 % was obtained at drum rotary speed of 150 rpm and air speed of 8.8 m/s. But the lowest cleaning ratio of 94.8% was obtained at drum rotary speed of 300 rpm and air speed of 4.9 m/s.

Analysis of shear rate inside a concrete truck mixer

In addition to the mixing energy applied to the fresh concrete (i.e. shearing during mixing), the shear history after mixing is also important. This applies especially to binder rich concretes like the different types of high performance concrete (HPC). With this in mind, the shear rate is analyzed inside a drum of a concrete truck mixer. The objective is to better understand the effect of transport of fresh concrete, from the ready mix plant to the building site. The analysis reveals the effect of different drum charge volume and drum rotational speed. Also, the effect of yield stress and plastic viscosity is investigated. The work shows that the shear rate decreases in an exponential manner with increasing drum charge volume. It is also shown that for a given drum speed, the shear rate decreases both with increasing plastic viscosity and yield stress.

DEVELOPMENT OF A TRACTOR-TRAILED RICE CLEANING AND MILLING MACHINE

The aims of the present research are to develop and evaluate tractor-trailed rice-milling machine. The factors affecting the performance of the developed milling-machine feeding rate, drum speed, grain moisture-content were studied. The performance measurements were productivity, total machine cleaning efficiency, total grain-losses, power required, specific energy and operational cost. The experimental results reveal that the highest values of productivity and machine efficiency were 1.35 Mg/h and 97.3 %. Meanwhile, the minimum required power and the specific energy were 16.82 kW and 14.55 kWh/Mg respectively for tractor-mounted rice milling machine after development, The minimum operating cost was 32.71 L.E/Mg These values were achieved under conditions of feed rate of 1.25Mg/h, drum speed of 800 rpm and moisture content of 14%.

MANFACTURING A TOMATO SEED EXTRCATING MACHINE

Manual extraction of tomato seed is a tedious operation and has some drawbacks such as incentive labor, excessive water use and much time consuming. Therefore, this study was dedicated to address the problems of manual extraction via manufacturing a simple machine to extract tomato seeds. Some of physical and mechanical properties of tomato fruits and seeds were measured. After that, an electric-motor powered machine was fabricated and followed by a techno-economic to investigate the potential effects of the machine operating parameters, namely, separating drum speed, feeding rate and drum with holes diameter on the machine evaluative criteria, namely, extractor productivity, extractor efficiency, seed purity, seed losses percentage and specific energy consumption. The analysis of data showed running the machine at the drum speed of 15.71 m/s (600 rpm), feeding the machine with 150 kg/h of tomato fruits and selecting the drum with holes diameter of 5 mm attained the following results to operate the developed machine economically: extractor productivity (9.12 kg/h), extractor efficiency (96.80%), seed purity (92%), seed losses percentage (3.20%) and specific energy requirement (0.042 kW.h/kg). Germination tests proved that the mechanical extraction of seeds did not harm the germinabilty of seeds as compared to the manual method. Lastly, the cost of manual process rose by about 42 and 182 % in comparison with the cost of mechanical system before and after discounting pulp tomato revenue, respectively.

Effect of Sieve Drum Inclination Angle on Wheat Grain Cleaning in a Novel Rotary Cleaning Device

Abstract. In this study, a novel rotary cleaning device was used for the separation and cleaning of wheat grains. This research analyzed the influence of the inclination angle of the sieve drum (K) of the device on the quality of these processes. In this article, the results obtained for four selected rotational speeds (nb) of the sieve drum are presented. The quality of the separation and cleaning of the wheat grains was evaluated using three cleaning process parameters: coefficient of plump grain mass separation (Wz), coefficient of fine impurities separation (Wd), and total coefficient of cleaning effectiveness (E). Based on statistical analysis of the results, the inclination angle of the sieve drum had a significant effect on the quality of the wheat grain separation process. Coefficient Wz was highest for sieve drum inclination angles of K = 0° and K = 2.5°, whereas Wd was highest for K = -2.5°. The total coefficient of cleaning effectiveness (E) was characterized by different values for different inclination angles of the sieve drum. Keywords: Cleaning effectiveness, Conical sieve, Rotary cleaning device, Wheat grain cleaning.

Influence of preparation of pig breeding wastes for use with division into factions during the pork production on greenhouse gases emissions

These results assess greenhouse gas emissions technologies preparation of slurry for use with mechanical fractionation processes using press filtration and gravity filtration on the complexes for the production of pork with hydraulic removal system. In preparation technology of liquid manure for use with mechanical fractionation effluents from pig-breeding complex comes in the receiving tank may be made: -on filter press «BAUER» for the separation of the solid fraction; On low speed drum separator (gravity filtration) at the same time getting to the inner surface of the drum, flows filtered. The isolated solids from the effluent as the drum rotates and moves along it falls through the outlet in the hopper when the accumulation of solids in the hopper are further dewatered drainage. It is shown that the technology of preparation of slurry for use with mechanical fractionation using processes: gravity filtration and press-filtration on the complexes for the production of pork with hydraulic removal system, the overall emissions of greenhouse gases by 1 head in CO2 equivalents amounted to within 124.59 kg per year, and 146.2 kg per year, respectively. Solid and liquid fractions in the future will still be processed on all technologies, prepared and used to fertilize farmland.

Evaluation of some effective parameters in performance of a helical two-sided manure distributor

Organic manures play an important role in improvement of soil fertility, increasing of crop yield and quality. The beneficial advantages of manure depend firstly on the method of spreading. Usually current manure spreaders cannot broadcast manures with different moisture contents and have non-uniform application rate. So the main objective of this research is performance evaluation of a new helical two-sided manure distributor that would be capable to spread manure at different moisture contents with long distribution width in uniform patterns. Experimental evaluation of the machine performance at two moisture content of manure in three forward velocities and three rotational speeds of drum showed that the moisture content of manure and rotational speed of drums had significantly effects (p = 0.01) on the distribution width and uniformity of the distribution pattern. The maximum distribution width of the machine at moisture content of 23% w.b. and 54% w.b. and in 1000 rpm rotational speed of drum were 19.3 m and 23.3 m respectively. Results indicated that the manure distribution uniformity increased by increasing the manure moisture and the distribution pattern of machine has an acceptable correlation with oval distribution pattern (p = 0.05).