Machine Operating Parameters Research Articles

Analytical Model of an Induction Motor Taking into Account the Punching Process Influence on the Material Properties’ Change of Lamination

The technologies of cutting the cores of electric machines change the magnetic properties and the loss of the electrical sheets used, affecting the machine’s parameters, mainly power losses and efficiency. This is particularly important in the case of induction motors, which are a significant consumer of electricity. Therefore, the problem of increasing their efficiency is important from the point of view of environmental impact. The article presents a method of approximating a material’s magnetic properties based on the results of measurements carried out with specimens of various widths. The presented method allows for an approximate representation of the changes in the structure of the material caused by the cutting technology. It is used in the analytical method for calculating motor parameters, and gives results that are in good agreement with the measurement. This method can determine the operating parameters of electrical machines of various sizes and rated powers.

Performance evaluation of mechanical feed mixers using machine parameters, operational parameters and feed characteristics in Ashanti and Brong-Ahafo regions, Ghana

Mechanical feed mixers are preferred for their higher efficiencies. A wide range of these feed mixers are available and used in the Ashanti and Brong Ahafo regions of Ghana due to a higher concentration of poultry farms in these regions. The performances of both local and foreign poultry feed mixers in the two regions were evaluated. This was carried out as a procedure to identify the types, measure machine parameters, operational parameters and feed characteristics relevant to the performance of poultry feed mixers. Data collected were analysed using statistical tools at 95% C.I. From the results, moisture content of the feed samples ranged from 9.21 to 11.08% (% wb), the geometric mean diameter of all samples ranged from 762.74 to 947.27 µm with the geometric standard deviation range of 2.35–2.50. The two dominating feed mixer types were the horizontal and vertical. The horizontal feed mixers indicated mixing time of 1.5–10 min, mixing speed of 40–80 rpm, energy consumption per mix of 0.9–3.8 kWh and blending uniformity with a coefficient of variation (CV = 7.19%), but relatively high maintenance cost per month. CV less than 10% is the percent commonly recognized by the feed industry as the cut-off for uniformity of mix analysis. The vertical feed mixers indicated low maintenance cost, mixing time of 15–30 min, mixing speed of 250–500 rpm, energy consumption per mix of 0.8–5.5 kWh and CV = 10.30–18.05%. Given that the horizontal feed mixers were found to have better performance metrics, there is the need to adapt the design for local process planning and manufacture, while substituting imported machine parts and components with locally available materials to optimize performance and minimise maintenance cost for the poultry and feed industries.

DESIGN FEATURES OF VIBRATION EQUIPMENT FOR DRYING HIGH-MOISTURE SEEDS

Significant difficulties arise in the process of post-harvest processing of high-moisture seed raw materials, in particular, in the process of drying seed lots of vegetable and melon crops such as squash, zucchini, pumpkin. Natural properties and preparatory technological operations cause the initial moisture content of seeds in the range from 55% to 75%, which is mainly due to unbound free moisture. For storage of sowing batches of seeds humidity should make 10% thus duration of postharvest processing and bringing of seeds to conditional properties should be carried out within days after the beginning of harvesting. Of all the branches of the agro-industrial complex, melon seed production remains the least mechanized, and its level of mechanization does not meet the requirements of modern production. Due to the lack of special equipment in the laborious processes of growing seeds and its refinement, machines are used that are not designed for this, which leads to large losses of seed material and its quality. The main reason for this situation is the lack of complete information, scientific research and substantiation of techniques, design and operating parameters of machines and their working bodies. Information that generates contradictions is often encountered. This is due to the lack of generalized theoretical and experimental studies of the drying process of high-moisture seed raw materials in the post-harvest period, which negatively affected the development of equipment and technological lines. In view of the above, the need for technical means for post-harvest treatment should be determined in terms of the need to process the entire crop on farms. All seeds of the harvested crop, which require a long stay in the dryer during the technological process, are subject to drying. The article presents a new design of a vibrating dryer and describes the features of its operation when removing moisture from seed materials from 55% to 10%.

Sowing uniformity of bed-type pneumatic maize planter at various seedbed preparation levels and machine travel speeds

Precision planters are important machines in the regime of modern technological agriculture. Field conditions, seed metering system and machine operating parameters affect the pneumatic planter performance. The pneumatic planter was evaluated to determine the effect of three tillage levels (L1, L2, and L3) and four travel speeds (S1, S2*, S3 and S4). The sowing uniformity of the planter was observed with respect to the horizontal distribution of seeds within a row and described by using the precision index (Ip), the multiple index (Imult), the miss-seeding index (Imiss) and the quality of feed index (Iqf). The results revealed that the tillage levels (L) and travel speed (S) had a significant effect (p<0.05) on dependent variables. The maximum Imiss (22.12%) was observed at L1 and S4 whereas the maximum Imult was observed at L1 and S1. The mean values of missing-, multi-, quality- feed and precision indices were 5.14%, 5.833%, 89.03% and 17.85% at L3, respectively. The mean values of multi-index 17.59%, 14.44%, 12.40% and 10.18%, quality feed index 74.07%, 75.92%, 75.74% and 74.07% and precision indices 21.47%, 23.26%, 25.51% and 28.53% were at S1, S2, S3 and S4, respectively. The study showed that maize could be seeding within an acceptable precise range by bed-type pneumatic planter subjected to the proper seedbed preparation level. Keywords: sowing uniformity, pneumatic planter, tillage levels, travel speed DOI: 10.25165/j.ijabe.20211401.5054 Citation: Ahmad F, Adeel M, Qiu B J, Ma J, Shoaib M, Aamir S, et al. Sowing uniformity of bed-type pneumatic maize planter at various seedbed preparation levels and machine travel speeds. Int J Agric & Biol Eng, 2021; 14(1): 165–171.

Modelling and controlling the process of cutting with complex-geometry tools to improve efficiency of mining machines and plants

Constant quality improvement through automation of production processes is an important prerequisite for increased viability of mining machines and plants. Factors that limit the automation of the cutting machining operations include the problem of controlling the chip formation and chip crushing. Solution of this problem necessitates theoretical description of the material cutting conditions for tools with curvilinear surfaces. The paper describes basic principles of modeling the cutting process using complex-geometry tools with curvilinear rake. The theory is based on the concept of chip formation as a process of inhomogeneous strain in the plastic zone where the chip originates. Based on the analysis of the stress-strain state in the cutting zone, criterial relationships were derived that correlate the geometric parameters of the chip shape and machining conditions of the curvilinear-rake tool. Prerequisites for chip breaking are stability of the chip shape during cutting, stable chip-to-obstacle contact, high chip stiffness and low flexibility. The machining conditions leading to chip fragmentation could be found by solving the strength problem. Through establishing the cause-and-effect relationships of the processes of chip formation, curling and breaking, new approaches to achieving favorable chip shape may be found by exerting deliberate impact on the plastic zone of the chip formation through optimizing the conditions for the chip flow off the tool. The established relationships between the output parameters of the cutting process and process conditions of cutting with a complex-geometry tool offer the way to control the chip flow parameters in various machining operations. The research is aimed at creating scientifically informed design codes and optimization of cutting parameters for tools with curvilinear chip-curling and chip-breaking rake surfaces.

Design and experiments of 4CJ-1200 self-propelled tea plucking machine

As agricultural labor is decreasing, famous tea production is nearly hard to sustain and is getting more and more expensive in China. To improve the mechanization of tea plucking, this paper designs a self-propelled track-type tea plucking machine that integrates mechanic, hydraulic and electronics. The main parameters of chassis were optimized based on conditions of tea garden. And, three different kinds of cutter blades were designed and analyzed about vibration performance with finite element software. Also, a rigid-flex mixed motion model was established. Based on the model and plots, it is explicit that: 1) the blades move in a sine law; 2) the blades take a symmetrical deform from middle to end while moving; 3) the deformation increases along the blade from the center to sides. The single factor experiment revealed that both travel speed and speed ratio of cutting and travelling had a significant effect on quality indexes (integrity rate, unpicking rate, stubble unevenness) of plucked tea leaf. By universal rotary combination experiment of quadratic regression, the regression equations of three indexes about two experimental factors were established. And, the comprehensive optimization of three indexes was conducted with software Design expert. The optimal operating parameters of machine are as follow: travel speed is 0.41 m/s, speed ratio of cutting and travelling is 1.06; prediction of three indexes are that integrity rate could be reach to 78.26%, unpicking rate reduced to 0.82%, stubble unevenness reduced to 1.30 mm. The results of verification experiment are that: integrity rate could be reach to 77.41%, unpicking rate reduced to 0.87%, stubble unevenness reduced to 1.23 mm. These test indexes that are very close to the predicted values, all surpass the requests specified in the standard of tea plucking with machine. In all, the optimized parameter set is indeed synthetically optimal one that enables the wide use of this tea plucking machine, which can be used in the tea garden that has a lengthways slope less than 18°, a crosswise slope less than 20°, and a height of tea trees between 50-120 cm. From above, the tea plucking machine investigated in this paper provides an effective solution to present tea picking problem that is the bottleneck of tea industry. Further studies need to do for making this machine more automated and intelligent. Keywords: agricultural machine, tea, harvesting, reciprocating cutter, model, design, experiment, optimization DOI: 10.25165/j.ijabe.20211406.5519 Citation: Han Y, Xiao H R, Song Z Y, Chen Q M, Ding W Q, Mei S. Design and experiments of 4CJ-1200 self-propelled tea plucking machine. Int J Agric & Biol Eng, 2021; 14(6): 75–84.

Sowing uniformity of bed-type pneumatic maize planter at various seedbed preparation levels and machine travel speeds

Precision planters are important machines in the regime of modern technological agriculture. Field conditions, seed metering system and machine operating parameters affect the pneumatic planter performance. The pneumatic planter was evaluated to determine the effect of three tillage levels (L1, L2, and L3) and four travel speeds (S1, S2*, S3 and S4). The sowing uniformity of the planter was observed with respect to the horizontal distribution of seeds within a row and described by using the precision index (Ip), the multiple index (Imult), the miss-seeding index (Imiss) and the quality of feed index (Iqf). The results revealed that the tillage levels (L) and travel speed (S) had a significant effect (p<0.05) on dependent variables. The maximum Imiss (22.12%) was observed at L1 and S4 whereas the maximum Imult was observed at L1 and S1. The mean values of missing-, multi-, quality- feed and precision indices were 5.14%, 5.833%, 89.03% and 17.85% at L3, respectively. The mean values of multi-index 17.59%, 14.44%, 12.40% and 10.18%, quality feed index 74.07%, 75.92%, 75.74% and 74.07% and precision indices 21.47%, 23.26%, 25.51% and 28.53% were at S1, S2, S3 and S4, respectively. The study showed that maize could be seeding within an acceptable precise range by bed-type pneumatic planter subjected to the proper seedbed preparation level. Keywords: sowing uniformity, pneumatic planter, tillage levels, travel speed DOI: 10.25165/j.ijabe.20211401.5054 Citation: Ahmad F, Adeel M, Qiu B J, Ma J, Shoaib M, Aamir S, et al. Sowing uniformity of bed-type pneumatic maize planter at various seedbed preparation levels and machine travel speeds. Int J Agric & Biol Eng, 2021; 14(1): 165–171.

Evaluating the effect of EPBM operational parameters on surface settlement in soft ground

Abstract The present study investigates the effects of some essential earth pressure balance machine (EPBM) operational parameters, including face, annulus and grout pressures, on ground surface settlement during tunnel excavation. A numerical soil-tunnel-fluid coupled model was developed using the finite difference method (FDM) in FLAC3D for the basis of this research. Hence, the effects of geostatic stress in the tunnel face and annulus and the grout pressure behind the segment on ground settlement were investigated by parametric analyses. The results indicated that a reduction in the boundary pressure (from 508 to 335 kPa) on the face and annulus space did not change the settlement significantly, altering the settlement from 1.18 to 1.48 mm. The results of parametric grout pressure analysis showed that applying a grout pressure equal to the vertical geostatic stress (i.e. 335 kPa) had a larger effect than applying horizontal geostatic stress (i.e. 357 kPa) to the tunnel face on controlling the ground settlement—i.e. 1.45 and 1.20 mm, respectively. A lateral earth pressure of below 1 (K0 &amp;lt; 1) led to the estimation of horizontal geostatic stress value that was lower than the vertical geostatic stress value, thereby applying a lower effect to controlling the ground settlement. Grout pressure increment relative to the vertical geostatic stress considerably reduced the ground settlement. However, an excessive rise in the grout pressure could lead to deformation and upward displacements in the form of ground heaving at a transverse distance of above 20 m from the tunnel axis.

Results of Theoretical Definition of Structural and Kinematic Parameters of Peeling Machine Working Elements

Introduction. Peeling the moistened grains before grinding allows removing most of the outer shells with impurities on them from the grain surface. At the present time, the most commonly used machines for peeling are devices operating on the principle of “compression and friction”, in which the grains move along the friction surfaces of the working bodies. The aim of this study is to define and select structural and kinematic parameters of the machine working bodies, which would most effectively perform the process of peeling, and to make energy assessment of grain peeling. Materials and Methods. To identify the dependence of the machine design and operating parameters on the inclination angle and punching angle of the sieve cylinder, a diagram of the movement of the grain along the inclined cylinder was drawn up using elements of the theory of the motion of material point on rough surfaces. The motion of grains on the cylinder surface is analyzed by the methods of analytical dynamics. Results. The values of the geometric parameters of the particle position at point A are expressed as a function of the cylinder inclination angle α and the angle characterizing the shape of the inclined line of stamping of the cylinder β. Energy assessment of grain peeling process was made. With the radius of the sieve cylinder R0 = 0.135 m, the width of the working annular gap к = 0.01 m, the length of the cylinder L = 0.4 m, the horizontal arrangement of the cylinder, the angular velocity of the shaft ω = 90 rad/s, the angle of inclination of the stamping β = 22º, the calculated power was P = 4.5 kW. Discussion and Conclusion. As a result of analyzing the motion trajectory of the grain located on the cylinder surface, there have been proposed the formulas relating the shape of the inclined punching line of the cylinder, characterized by the angle β, to the inclination angle α, the radius R0 of the cylinder, the shaft angular velocity and the grain frictional properties. The obtained analytical dependencies can be used for the approximate definition of the peeling machine design and kinematic parameters.

Predicting TBM performance in soft sedimentary rocks, case study of Zagros mountains water tunnel projects

Soft rock formations are widespread throughout the mountainous regions of the world including the mountains of western and southern Iran. Therefore, it is very common to pass through soft rock formations while building long tunnels for various purposes in the mountainous regions. The soft sedimentary rocks are frequently found in Zagros Mountains located in the south and west of Iran, where most of Iran's water conveyance projects (long and deep tunnels) have been constructed or are under construction. The behavior of these rocks in tunneling projects has received much attention in the past decades, but some features comprising the boreability and performance of tunneling machines in such rocks have received little attention. Many of these sedimentary rocks, especially those composed mainly of clay minerals, exhibit “non-structurally controlled” behavior in deep tunnels and below the groundwater level, and are completely continuous. During loading by disc cutters, these rocks usually exhibit plastic behavior, and the formation of chips in these rock types are often different than brittle and discontinuous rocks. Obviously, this necessitates the development of special models to predict the TBM performance in these rocks. In this study, the machine performance in soft rock formations along some of the Zagros Mountains water tunnel projects has been investigated. Efforts have been made to develop a special empirical model for continuous (intact) soft rock formations to complement the models presented in previous studies. Evaluation of the relationships between different geological and machine performance and operating parameters in these projects indicated that there is a strong correlation between intact rock properties (uniaxial compressive strength) and two parameters including penetration and cutter load. New empirical models developed based on statistical analyses of machine performance in these projects are presented for predicting TBM performance in similar conditions.

An AIoT-based system for real-time monitoring of tunnel construction

Shield machine performance and tunnelling-induced settlement are the main concerns during the tunnelling process. This study proposes an artificial intelligence Internet of Things (AIoT)-based system for real-time monitoring of tunnel construction. Shield machine operational parameters and tunnelling-induced settlement can be transferred and stored in real time by an AIoT system. Thereafter, shield operational parameters and tunnelling-induced settlement prediction models based on machine learning algorithm random forest (RF) are established based on the collected data. The models are further employed to predict shield operational parameters and ground response at the next step. This dynamic system was applied to a practical tunnel engineering. The results indicate the implementation of such process from the data collection, training and updating of RF-based models, and decision making of controlling shield machine performance can be completed within 15 minutes, which is much less than the time of excavating and installing a segmental ring, ensuring the real-time control of shield machine. Based on the predicted shield operational parameters, maximum and mean prediction error of the tunnelling-induced settlement can be controlled within 5 and 2.5 mm, respectively. The AIoT-based system improves the information and automation level during the construction process, facilitates decision-making and avoids accidents.

Effects of Machine Operating Parameters on the Grating Time of a Double-Action Cassava Grater with Automated Contact Plate: A Response Surface approach

Processing time needs to be considered as an essential attribute of an agricultural product processing system. Therefore, the effect of machine operating parameters on the grating time of a double-action cassava grater with automated contact plate was studied. A $$2 \times 5$$ central composite rotatable design of response surface methodology was adopted for the experiments. The machine operating parameters were conveying time and contact plate control timing, at grating speeds of $$765$$ , $$865$$ and $$965\;{\text{rpm}}$$ . The grating time at each grating speed and the minimum overall grating time were evaluated. Data obtained were analyzed using multiple linear regression at p = 0.05. The grating time ranged from 211–412, 188–383 and 158–353 s at grating speeds of 765, 865 and 965 rpm, respectively, while the minimum overall grating time of 158 s was obtained at conveying time, contact plate control timing and grating speed of 3.19 s, 5.85 s and 965 rpm, respectively. The numerical optimization employed, with the aim to minimize the grating time revealed optimal values of conveying time of 6.67 s, contact plate control timing of 5.85 s and grating speed of 865 rpm for the optimum grating time of 158.74 s at the desirability of 0.9289. The mathematical models relating machine operating parameters to grating time were developed. Coefficient of determination ( $$R^{2}$$ ) for the grating time at 765, 865 and 965 rpm was $$0.99$$ , $$0.99$$ and $$0.99$$ , respectively. The deviation between experimental and predicted values ranged from 0.01–0.66, 0.01–0.48 and 0.01–0.69 for grating time at grating speeds of 765, 865 and 965 rpm, respectively. The result obtained from this study will provide a worthwhile machine operating variables capable of controlling the overall processing time for satisfactory production yield in a cassava processing industry.

Effect of frother strength on gas dispersion in a cavitation sparger measured by electrical resistance tomography

Axial dispersion in column flotation is critical for optimizing particle-bubble interaction and maximizing recovery. The effect of different flotation frothers on axial gas dispersion rates in a column flotation cell were measured using electrical resistance tomography (ERT). Gas holdup can be measured using ERT and utilized in the determination of axial gas dispersion rate in the column. The ERT is constructed with two sensor planes making it possible to simultaneously capture gas holdup values at and immediately above the cavitation sparger. Three frothers of varying strengths were used to investigate axial dispersion rates. Experimental conditions were modified by altering the superficial gas rate, frother concentration, and sparger pump speed. Utilizing a two-phase (gas–liquid) system, the effects of varying experimental conditions were captured and are represented using concentration tomograms. There is a strong positive correlation between axial dispersion rate, frother strength, and machine operating parameters.

Mathematical model of compression and injection working processes in a cross-free piston hybrid energy machine with a significant ratio of nominal suction pressures in the compressor and pump sections

A mathematical model of the operation of a cross-free piston power machine with a significant ratio of nominal suction pressures in the compressor and pump sections is developed. The dynamics of the phase division boundary in the gap seal is studied. A breakthrough of gas from the compressor section through the gap seal into the pump section is considered. The basic numerical relationships of machine operation parameters are determined. A numerical experiment confirmed the conceptual model of gas breakthrough into the pump section. Keywords: compressor, pump, mathematical model, piston hybrid energy machine, workflow, suction pressure. Scherba_V_E@list.ru

Actual performance analysis of a double shield TBM through sedimentary and low to medium grade metamorphic rocks of Ghomrood water conveyance tunnel project (lots 3 and 4)

In this paper, after a brief description of engineering geological properties of Ghomrood water conveyance tunnel project (lots 3 and 4 with a total length of 18 km), the actual performance of the machine during the excavation of tunnel through sedimentary and low to medium grade metamorphic rocks has been analyzed. Subsequently, using data collected during pre-construction and construction phases of the project, the relationships between rock mass properties and measured machine performance parameters have been investigated and proposed as a prediction model which can be used in future projects in which similar geological conditions are encountered. Results of analyses indicated that there are strong relationships between TBM performance and engineering geological conditions of the tunnel alignment.

XGBoost based intelligent determination system design of tunnel boring machine operation parameters

XGBoost based intelligent determination system design of tunnel boring machine operation parameters

The influence of constraint rolls on temperature evolution and distribution in radial ring rolling

Abstract Producing nearer to net-shape hot rolled rings whilst meeting demanding product property requirements is a major industrial challenge, especially in high value materials such as nickel-based superalloys. Recent process innovations propose additional tooling to improve control over the geometric accuracy, but it is not known what influence this will have on the temperature distribution and product properties. To study this, a set of 24 thermally-coupled numerical simulations was conducted for a key material test case, Inconel 718, with a furnace temperature of 1030 °C. The thermal parameters used in the model were validated against an a newly-conducted full industrial trial, and both average surface temperature prediction and rolling tool temperature were found to be accurate to within ±10 °C. The set of simulations focused on the production of two target ring geometries; for each target ring, four different rolling scenarios were developed, covering a realistic range of machine operating parameters. All eight of these scenarios were simulated with three different tooling set-ups, using two, four and six constraint rolls. For a typical rolling scenario with two constraint rolls, the average surface temperature was found to drop by 79 °C after transfer to the machine, and then by a further 54 °C during rolling. Trebling the number of constraint rolls doubled the temperature drop to 113 °C. By comparison, a factor 2.7 increase in rolling time led to a factor 3.0 increase in temperature loss to 166 °C. Simulations for the second, slenderer, target geometry predicted comparable surface temperature drops, but increased temperature loss in the core of the ring. In Inconel 718 regions of the ring that drop below 900 °C experience strongly retarded dynamic recrystallization, rendering them prone to damage. Trebling the constraint rolls was found to increase the area vulnerable to damage by 0–20%, across the 8 scenarios. These predictions suggest that the influence of constraint rolls could to some extent be mitigated by reasonable reductions in rolling or transfer time. However, if used to produce slenderer, nearer to net-shape rings with larger overall reductions and longer process times then temperature and product property control will be difficult.

Modeling of an efficient high power wind energy conversion system using self-excited multi-phase machines

Self-Excited Multi-phase Induction Generators (SEMPIG) producing power from wind turbines infar-flung fields are receiving the interest of recent researchers. Small and medium energy wind generators involve 3-phase induction generators. SEMPIG with significant reliability, better fault tolerance, reduced harmonics, and high power-handling capability using reduced current per phase and maintaining the same per phase voltage makes it the promising contender in high-power WECS. This investigation analyzes the proficiency of energy efficient stand-alone self-excited seven-phase induction generator (SE7PIG) in wind energy schemes. This paper develops a cogent model from the two-phase equivalent circuit of SE7PIG using Matlab/Simulink. The study examines the modeling aspects of the SE7PIG with incorporated significant 7-rectifier and 7-phase inverter. The machine operational parameters speed, torque, voltage and current are presented. The 2MW WECS with 7-phase induction generator is analyzed with and without DC link converter. The results are compared with the 3-phase counterpart to illustrate the efficacy of SE7PIG for megawatt wind-power generation. The paper confirms the competence of SE7PIG with better fault tolerance and significant energy output with a decrease in phase current.

Development and testing of a double‐action cassava grater with an automated contact plate

AbstractCassava grating is a size reduction process that converts peeled cassava tubers into cassava mash. Grating cassava tubers using the conventional graters makes the process tedious and labor‐intensive. Thus, a double‐action cassava grating machine with an automated contact plate was developed, and the machine performance was evaluated. A 3 × 5 central composite rotatable design (CCRD) of response surface methodology ( RSM) was adopted for the performance test experiments. The machine parameters are grating speeds, g s (765, 865, and 965 rpm), conveying time, c t (7.37, 5.84, 4.40, 3.00, and 1.69 s); (6.67, 5.00, 3.55, 2.40, and 1.19 s); and (5.97, 4.38, 3.19, 2.00, and 0.97 s) at 765, 865, and 965 rpm respectively; and the contact plate control timing, cpct (5.85, 11.91, 17.16, 26.69, and 30.44 s) were selected. The throughput ( TP) and grating efficiency ( GE) were determined. Data analysis was carried out using multiple linear regressions at α = 0.05. Maximum TP of 26.64 kg/hr was obtained at g s (965 rpm), c t (3.19 s), and t scp (5.85 s), while maximum GE of 74.25% was obtained at g s (765 rpm), c t (4.40 s), and t scp (17.16 s). TP increased with an increase in g s, but decreased with an increase in c pct and c t. Hence, the developed cassava grating machine is a viable option to large scale cassava processors due to the ease of operation, less processing time, and less man‐power demand as a result of machine automation.Practical ApplicationsDespite a considerable improvement in the advancement of machines for grating cassava tubers, there is still some tedious activities experienced during the process of cassava grating. To this end, there is a need for innovation of technological application in cassava grating. Thus, a double‐action cassava grater with automated contact plate capable of integrating several operations involved in cassava grating and finishing in one pass was developed, and the performance was evaluated. CCRD of RSM was employed to design the experiment to evaluate the effects of the machine operating parameters on the performance of the cassava grating system based on the machine throughput and grating efficiency. The developed cassava grating system will be a useful option for large‐scale cassava processing due to the continuous grating operation achieve in the machine, which is suitable for cassava processing industry where the large scale of cassava tubers is being processed.

A NEW MODEL FOR PREDICTING THE ADVANCE RATE OF A TUNNEL BORING MACHINE (TBM) IN HARD ROCK CONDITIONS

The prediction of the advance rate of a Tunnel Boring Machine (TBM) in hard rock conditions is one of the most impor- tant concerns for estimating the time and costs of a tunnel project. In this paper, in the first step, a model based on Rock Engineering Systems (RES) is proposed to predict geotechnical risks (representing media characteristics) in rock TBM tunnelling. Fifteen main parameters that influence the geotechnical hazards were used in the modelling. In establishing an interaction matrix and also a parameter rating, the views of five experts were taken into account. The Vulnerability Index (VI) (geotechnical risk levels) for 2058 datasets out of 2168 sets of data from 53 geological zones in 11 km of the Zagros long tunnel was obtained. In the second step, based on the machine operating parameters such as torque, cutter head rotation per minute, cutter normal force and media characteristics (represented by VIs), which were used as input parameters and advance rate was used as an output parameter, while using 2058 datasets, linear and non-linear multiple regression analyses were carried out. 110 datasets (out of 2168 datasets), which were not used in the modelling, were ap- plied to evaluate the performance of regression models and other models in literature and the results were compared. The obtained results showed that the new linear model proposed with R2=0.83 and RMSE=0.12 has a better performance than the other models.