Step Feed Research Articles

Influence of substrates concentrations on the dynamics of oxygen demand and aeration performance in ideal bioreactors

The effect of bioreactor configurations on the dynamics of aeration modelling was investigated by incorporating three different correlations from the literature to estimate α-factors into the aeration model. Estimated air flow rates using the three correlations were then validated against experimental data obtained from pilot sequencing batch reactors (SBRs). Two identical SBRs were operated in parallel; one received raw wastewater and the other received primary treated wastewater. The validated aeration model was then used to evaluate aeration dynamics in different bioreactor configurations, both for nitrification only and nitrification/denitrification, with the three different correlations. The current study is the first to investigate the validity of the aforementioned correlations using various bioreactor configurations and to establish that the bioreactor configuration not only impacts spatial and temporal biological oxygen demands as currently understood but also oxygen transfer efficiency. The first correlation based on the real-time bioreactor soluble chemical oxygen demand (sCOD) was able to predict the temporal measured air flow rate in the pilot SBRs. The second correlation based on the influent COD overestimated the air flow rates as it considered the impact of the influent loading rates on the α-factor and overlooked the improvement in α-factor due to biodegradation. The third correlation based on MLSS concentrations underestimated the air flow rates at the beginning of the aeration cycle as it ignored the impact of influent loading rates on the α-factor and considered only the insignificant change in MLSS during the aeration cycle. In terms of bioreactor configuration, the model-based analysis showed that the first correlation is suitable for designing SBR, plug flow reactor (PFR), step-feed PFR, and completely mixed stirred reactor (CSTR) systems, and the third correlation is suitable for designing CSTRs and membrane bioreactors (MBRs), while the second correlation was not accurate in any of the reactors modelled. When nitrification was targeted, the CSTR reduced aeration energy by 44 %–49 % compared to the PFR, and 41 %–43 % when both nitrification and denitrification were targeted. Compared to the plug-flow reactor, the step-feed PFR reduced aeration energy by 9% when nitrification only was targeted. However, when pre-denitrification was added, both systems showed the same aeration energy consumption. Pre-denitrification reduced organic loadings to aeration tanks and decreased aeration energy by 22 %, 11 %, 15 %, and 14 % in PFR, CSTR, PFR step feed and MBR systems, respectively.

Effect of COD/N ratios and DO concentrations on the NOB suppression in a multi-cycle SBR

NOB could be suppressed in a multi–cycle sequential batch reactor with an integrated control of four step feeding, low DO (dissolved oxygen) concentrations and short sludge retention time, but which is the key control parameter of mainstream NOB suppression remained unclear. This study investigated the effect of COD/N ratios and DO concentrations on NOB suppression with different COD/N ratios and DO concentrations. Nitrite accumulate rate reached 93.8% at COD/N ratio of 4:1 and 1.5 mg DO/L, and ranged between 73.4% and 80.0% at COD/N ratios of 1.4:1 and different DO ranges between 0.3 mg/L and 1.1 mg/L. As COD/N ratios decreased to 0.8:1, nearly no nitrite accumulated at 0.6 mg DO/L. Statistical results showed that there was a significant relationship among COD/N ratio, nitrite accumulate rate and total nitrogen removal efficiency, while there was no correlation between DO concentration and nitrite accumulate rate or total nitrogen removal efficiency. Therefore, the main reason of NOB suppression was nitrite competition between denitrifiers and NOB, rather than oxygen competition between AOB and NOB.

Optimization of the step feeding ratio for nitrogen removal by SBR using technique for order preference by similarity to ideal solution (TOPSIS)

The performance of nitrogen (N) removal was investigated by altering the influent step feeding in a sequencing batch reactor (SBR). The optimum condition for influent step feeding was analyzed using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) with entropy weight method, considering the C/N ratio range 1.5 to 4.5. The results showed that the SBR with the multi-step-feeding system achieved a high nitrogen removal rate of 92.7% at the three-step influent feeding mode. Nitrogen removal was significantly improved due to the multi-step influent feeding, which provided the required carbon source in the anoxic phase for the removal of nitrate that enhanced the denitrification process. The highest nitrogen removal rate at real-time operation was observed at the three-step feeding mode with 60% primary feeding, 30% secondary feeding, and 10% tertiary feeding, respectively. TOPSIS analysis results also showed that the optimum step feeding ratio was identical to the real-time operation of the SBR.

Experimental Investigation of Surface Roughness for AA 3003-0 Aluminium Alloy Using Single Point Incremental Forming

Single point incremental forming is a sheet metal forming technique that produces intricately shaped specially made parts. A tool with a hemispherical end is used to produce continuous local plastic deformation, which improves the formability of a sheet metal blank. The surface roughness of AA 3003-O aluminium alloy was investigated in this experiment by varying tool diameter, sheet thickness, step size, and feed rate. A four-factor central composite design with four centre points is used to create a mathematical model of the design parameters that yield the best response. The Analysis of Variance (ANOVA) is used to look at the outcomes. The experiments show that surface roughness has the greatest individual impact of tool diameter, followed by step size, feed rate, and sheet thickness. The experimental results show that lower sheet thickness has no effect of tool size. The middle range of design parameters yields contradictory results. It is also discovered that surface roughness and sheet thickness have a direct relationship. With the right combination of tool diameter, feed rate, and sheet thickness, the surface finish was improved by more than 30%.

Effect of COD:N ratio on biological nitrogen removal using full-scale step-feed in municipal wastewater treatment plants

This study investigated the effect of low and high chemical oxygen demand (COD):N ratios on biological nitrogen removal and microbial distributions in full-scale step-feed (SF) municipal wastewater treatment plants (WWTPs) in Thailand (SF1) and Taiwan (SF2). The SF1 WWTP had a low COD:N (4:1) ratio, a long solids retention time (SRT) (> 60 d), and low dissolved oxygen (DO) conditions (0.2 mg L− 1 in anoxic tank and 0.9 mg L− 1 in aerobic tank). The total nitrogen (TN) removal efficiency was 48%. The SF2 WWTP had a high COD:N (10:1) ratio, a short SRT (7 d), and high DO (0.6 mg L− 1 in anoxic tank and 1.8 mg L− 1 in aerobic tank). The TN removal efficiency was 61%. The nitrification and denitrification rates from these two plants were inadequate. Using a quantitative polymerase chain reaction (qPCR) technique, the populations of ammonium oxidizing bacteria (AOB) and ammonium oxidizing archaea were quantified. Measurement of ammonia monooxygenase (amoA) gene abundances identified these AOB: Nitrosomonas sp., Nitrosospira sp., Nitrosoccus sp. and Zoogloea sp. Higher amounts of the archaeal-amoA gene were found with long SRT, lower DO and COD:N ratios. Abundance of Nitrobacter sp. was slightly higher than Nitrospira sp. at the SF1, while abundance of Nitrobacter sp. was two orders of magnitude greater than Nitrospira sp. at the SF2. More denitrifying bacteria were of the nirS-type than the nirK-type, especially at higher COD:N ratio. Most bacteria belong to the phyla Acidobacteria, Actinobacteria Bacteroidetes, Chloroflexi, Proteobacteria. The results from this work showed that insufficient carbon sources at the SF1 and high DO concentration in anoxic tank of SF2 adversely affected nitrogen removal efficiencies. In further research work, advanced techniques on the next generation sequencing with different variable regions should be recommended in full-scale WWTPs.

An integrated mainstream and sidestream strategy for overcoming nitrite oxidizing bacteria adaptation in a continuous plug-flow nutrient removal process

An integrated mainstream aeration and sidestream sludge treatment was demonstrated to be effective in overcoming the adaptationof nitrite oxidizing bacteria (NOB) in an anoxic/oxic process. Results showed that by employing the alternating free nitrous acid and free ammonia (FNA/FA) sidestream sludge treatment alone, nitritation was established but varied, which was addressed by integrating alternating aeration with step feeding (ALASF) in reactor. Two critical considerations contributed to stable effluent nitrite accumulation (>83.8 %)and nitrogen removal (>83.0 %): 1) aerobic sludge rather than return sludge should be taken for FNA/FA treatment to avoid anoxic starvation which facilitated NOB recovery; 2) ALASF ensured timely denitritation and created constant anoxic disturbance for NOB inhibition. Nitrospira and Nitrobacter after 540-day operation were 0.38 % of seed sludge.A20 % reduction of operating cost was obtained in this nitritation process. This study moved nitritation one step closer to application in continuous plug-flow process from municipal wastewater.

Optimal design and effective control of Kaibel column with liquid-only transfer streams for quaternary distillation

The Kaibel column (KC) is considered to be energy effective and capital economical replacement of conventional distillation sequences for quaternary distillation. However, the industrialization of such a structure is still hesitant due to increased complexity and related uncertainties. Compared to the highly integrated KC, distillation configurations with liquid-only transfer streams (LTS) are more easily understandable and acceptable to the industrial community. A KC-LTS configuration is therefore investigated through an optimal design and controllability comparison to the conventional direct sequence (DS). When separation of aromatics is proposed as a case study, the results demonstrate the economic superiority of KC-LTS to DS in terms of the total annual cost. Considering the controllability using composition controllers, the former structure performs as favorable as the latter when tackling a ±20% step changes in throughput and feed composition. An inferential temperature control strategy is also established for KC-LTS. Good controllability is generally realized in most cases at handling relatively small (10%) throughput and feed composition disturbances, except for large product offsets when resisting large (20%) feed perturbations. To further improve its dynamic control effectiveness, an intensified control option with three composition control loops is successfully proposed to handle 20% step feed disturbances. Overall, this work expands LTS to quaternary distillation, suggesting a competitive substitute of the well-known KC for both academic and industrial purposes.

Development of a Modified Hilbert Curve Fractal Antenna for Multiband Applications

This paper presents the development of a Modified Hilbert Curve Fractal (MHCF) antenna with parasitic patches for multiband applications. The fractal antenna has been designed on a dual-layer substrate having a dimension of 50 × 60 × 3 mm simultaneously fed by a modified coplanar waveguide (CPW) feed. The geometry of the step feed has been optimized using swarm intelligence-based Dragonfly Optimization (DO) technique to enhance the bandwidth. The antenna offers multiband resonating characteristics with a bandwidth of 0.315 GHz (0.68–0.99 GHz), 3.220 GHz (3.98–7.20 GHz), 2.955 GHz (8.043–10.998 GHz) and 1.94 GHz (12.7–14.64 GHz). The proposed antenna indicates a higher degree of impedance matching with a stable omnidirectional radiation pattern at all resonating frequencies. The reported antenna has been fabricated and tested for the validation of resonating and radiation characteristics. Simulated and measured results are found in good agreement with each other. The fractal antenna is useful for radiolocation in Ultra High Frequency (UHF) band and for aeronautical radionavigation service (ARNS) in C-band, X-band and Ku-band as defined by International Telecommunication Union (ITU).

An appropriate technique for treating rural wastewater by a flow step feed system driven by wind-solar hybrid power

Most rural wastewater treatment facilities require aeration equipment to ensure sufficient dissolved oxygen (DO) during processing. Operation and maintenance are costly, and cannot be met in many areas with poor economic levels. This has led to further deterioration of the rural water environment and aroused much attention. This work reports a plug-flow step feed system utilizing wind and solar hybrid energy for rural wastewater treatment. Under certain climatic conditions, the wind energy and solar energy provided complimentary power generation, and an automatic control system (without batteries) was constructed. The corresponding control logic for multi-energy level operation was developed. Furthermore, the power generation efficiency of the system, the pollutant removal, and its mechanism on the bioreactor were also analyzed. According to the monitoring of meteorological conditions, wind and solar resources at the test site were abundant, and the electricity generated by the power generation was sufficient to meet the operational needs of the equipment. Energy efficiency can reach 80.0%. The characteristics of pollutant removal in each process section were studied on spatial and temporal dimensions. Results showed that the wastewater treatment process reached mean removal efficiencies of chemical oxygen demand (CODcr), NH4+-N, total nitrogen (TN) and total phosphorus (TP) were 90.2%, 94.3%, 61.4% and 63.1%, respectively. Analyses of microbial community richness and group changes in each anoxic/aerobic reaction chamber in the biofilm reactor showed that the population structure was relatively stable and that there were abundant functional bacteria capable of degrading pollutants in each aerobic and anoxic unit. This system can thus be a more sustainable treatment process than traditional techniques used for rural wastewater treatment, providing a new design approach for low-energy consumption and unattended rural wastewater treatment.

Evaluation of Step Feeding Strategy in One-Stage Simultaneous Partial Nitritation, Anammox and Denitrification (SPNAD) Process

Fast start-up of simultaneous partial nitritation, anaerobic ammonium oxidation (anammox) and denitrification (SPNAD) process was achieved within a month by applying step feeding strategy without carbon source addition in the acclimation period. The decreasing cycle number of step feeding strategy successfully improved the SPNAD process performance and enhanced nitrogen and organic removal performance for treating sidestream wastewater. The 3-cycle step feeding strategy obtained higher average values of nitrogen loading rate (NLR), nitrogen removal rate (NRR), ammonium removal rate (ARR) and COD removal rate (CRR) of 0.50, 0.31, 0.45, and 0.18 kg/m3/day, respectively, than 10-cycle and 5-cycle step feeding strategy. The step feeding strategy also contributes in maintaining DO, pH and ORP sensors performance stability even after being operated in long-term duration.

Step-feeding ratios affect nitrogen removal and related microbial communities in multi-stage vertical flow constructed wetlands

Step-feeding (SF) strategies have been adopted in several types of constructed wetlands (CWs) to enhance nitrogen (N) removal. However, it is unclear how SF affects the N-transforming bacterial communities in CWs. Herein, four multi-stage vertical flow constructed wetlands (MS-VFCWs), each including three vertical flow stages (stage 1–3), were operated under different SF ratios (0%, 10%, 20% and 30%) in the stage 2. The physicochemical influent and effluent parameters, i.e., redox potential (ORP), pH value, chemical oxygen demand (COD), total nitrogen (TN), ammonia (NH4+-N), nitrate (NO3−-N), and nitrite (NO2−-N), free-ammonia (FA) concentration, COD/TN ratio, as well as the abundance, structure, and activity of N-transforming bacteria were investigated. Results showed that N removal in a multi-stage vertical flow constructed wetland in the absence of SF was 45.0 ± 7.74%. Alternatively, a combined SF ratio of 20% increased N removal to 61.7% ± 4.50%, accounting for a 37.1% increase compared to the SF ratio of 0%. In the microbial community, FA was determined to be the primary physicochemical parameter governing nitrification processes in MS-VFCWs. Further, partial nitrification processes played an important role in ammonium removal during stage 1, while ammonia-oxidizing archaea were major contributors to ammonium removal in stage 3. Furthermore, abundance of nitrite reductase genes (nirS, nirK) and relative abundance of denitrifying bacteria increased with increasing SF ratio; while the nirS/nirK ratio and the alpha diversity of nirK denitrifiers were significantly affected by SF ratios, and the influent NO3−-N concentration was related to a shift in denitrifier composition toward strains containing the nirS gene. Autotrophic (e.g., Thiobacillus, Sulfurimonas, Arenimonas, Gallionella and Methyloparacoccus) and facultative chemolithoautotrophic (e.g., Pseudomonas and Denitratisoma) denitrifying bacteria were enriched in stage 2. Hence, the synergy between heterotrophic and autotrophic denitrifying bacteria promoted excellent N removal efficiency with a low COD/TN ratio.

Biosorption of cadmium and copper ions from industrial wastewaters by waste activated sludge

ABSTRACT In this study, the removal of cadmium and copper ions from aqueous solutions was investigated by waste activated sludge (WAS) under three conditions: (1) without any aeration and feeding, (2) by aeration without feeding and (3) by simultaneous aeration and feeding. The initial concentration, temperature, contact time, aeration and feeding had influence in Cd2+ and Cu2+ removal. The maximum removal of Cd2+ and Cu2+ was obtained with an initial concentration of 5 mg/L of each heavy metal that occurred in the third step (aeration and feeding of activated sludge) with removal efficiency of 75.45% and 76.91% for Cd2+ and Cu2+, respectively. This study showed that WAS has a high biosorption removal capacity for Cd2+ and Cu2+ and can be used as an effective biosorbent for the removal of cadmium and copper and/or other types of heavy metals from industrial wastewaters.

Simulation study of pressure swing adsorption to purify helium using zeolite 13X

A two-bed pressure swing adsorption system on a commercial type of zeolite 13X adsorbent has been studied numerically over a wide range of operating conditions to helium separation from gaseous mixture. The model includes energy, mass and momentum balances. The coupled partial differential equations are solved using fully implicit forth order Rung-Kutta scheme in the simulation. The effects of adsorption step pressure, adsorption step time and feed flow rate on the helium purity and recovery were investigated. Results shown that as the adsorption step pressure increases the helium purity will be increased. In addition, the helium recovery increases, and the helium purity decreases when the feed flow rate increases. Finally, the simulation results indicated a very good agreement with some current literature experimental work.

The effectiveness of step feeding strategies in sequencing batch reactor for a single-stage deammonification of high strength ammonia wastewater

A single-stage deammonification with a sequencing batch reactor (SBR) that simultaneous nitritation, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) occur in one reactor has been widely applied for sidestream of wastewater treatment plant. For the stable and well-balanced SNAD, a feeding strategy of influent wastewater is one of the most important operating factors in the single-stage deammonification SBR. In this study, single-stage deammonification SBR (working volume 30L) was operated to treat a high-strength ammonium wastewater (1200 mg NH4+-N/L) with different feeding strategies (single feeding and nine-step feeding) under the condition without COD. Each cycle of the step feeding involved 6 sub-cycles consisted of aerobic and anoxic periods for partial nitritation (PN) and anammox, respectively. Contrary to unstable performance in the single feeding, the step feeding showed better deammonification performance (0.565 kg-N/m3/day). Under the condition with COD, however, the nitrogen removal rate (NRR) decreased to 0.403 kg-N/m3/day when the Nine-step feeding strategies had an additional denitrification period before sub-cycles for PN and anammox. The NRR was recovered to 0.518 kg-N/m3/day by introducing an enhanced multiple-step feeding strategy. The strategy had 50 cycles consisted of feed, denitrification, PN, and anammox, instead of repeated sub-cycles for PN and anammox. The multiple-step feeding strategy without sub-cycle showed the most stable and excellent deammonification performance: high nitrogen removal efficiency (98.6%), COD removal rate (0.131 kg-COD/m3/day), and COD removal efficiency (78.8%). This seemed to be caused by that the elimination of the sub-cycles might reduce COD oxidation during aerobic condition but increase the COD utilization for denitrification period. In addition, among various sensor values, the ORP pattern appeared to be applicable to monitor and control each reaction step for deammonification in the multiple-step feeding strategy without sub-cycle. Further study to optimize the number of multiple-step feeding is still needed but these results show that the multiple-step feeding strategy can contribute to a well-balanced SNAD for deammonification when treating high-strength ammonium wastewater with COD in the single-stage deammonification SBR.

Modified ground with 50 Ω step fed WLAN notch 2 × 2 MIMO UWB antenna

In this research paper, an optimized 2 × 2 MIMO UWB antenna (antenna-E) with half circled radiators as well as 50 Ω step fed has been introduced. The proposed UWB MIMO antenna has been evolved from recent peer published papers that provide WLAN notch (5.15-5.85GHz), ultra wide band width (3.1-10.6 GHz) and again a very good isolation (−20 dB) also maintained. In this paper the evolutions have been derived from antenna-A to antenna-E. The Ultra wide band is achieved by using step feed line, cutting a metal strip on a partial ground plane, a rectangular slot underneath the feed line of each radiator in antenna-E. A high isolation (−20 dB) is obtained by introducing two inverted Г shaped stubs in the ground plane. Both antenna-D and antenna-E maintain high isolation (−20 dB). But antenna-E performs better isolation compared to antenna-D. The notch at WLAN band (5.15-5.85GHz) is achieved by etching rectangular C-shaped slot on the both the radiators. In antenna-E two radiators are placed horizontally where as in antenna-D two radiators placed orthogonally. It has been observed that the dimension of final outcome (antenna-E) is reduced by 33% compared to antenna-D without compromising the overall performance of the antenna.

Hydrogen production via chemical looping steam reforming of ethanol by Ni-based oxygen carriers supported on CeO2 and La2O3 promoted Al2O3

This work studies the effects of Ce4+ and/or La3+ on NiO/Al2O3 oxygen carrier (OC) on chemical looping steam reforming of ethanol for hydrogen production - alternating between fuel feed step (FFS) and air feed step (AFS). Suitable amount of Ce- and La-doping increases OC carbon tolerance. The solubility limit is found at 50 mol% La in solid solution. At higher La-doping, La2O3 disperses on the surface and adsorbs CO2 forming La2O2CO3 during FFS. From the 1st cycle, 12.5 wt%Ni/7 wt%La2O3-3wt%CeO2–Al2O3 (N/7LCA) displays the highest averaged H2 yield (3.2 mol/mol ethanol) with 87% ethanol conversion. However, after the 5th cycle, 12.5 wt%Ni/3 wt%La2O3-7wt%CeO2–Al2O3 (N/3LCA) exhibits more stability and presents the highest ethanol conversion (88%) and H2 yield (2.7 mol/mol ethanol). Amorphous coke on the OCs decreases with increasing La3+ content and can be removed at 500 °C during AFS; nevertheless, fibrous coke and La2O2CO3 cannot be eliminated. Therefore, after multiple redox cycles, highly La-doped OCs exhibits rather low stability.

Forming, fracture and corrosion behaviour of stainless steel 202 sheet formed by single point incremental forming process

This work aims to determine the forming limit of stainless steel 202 sheet having 0.8 mm thickness during Single Point Incremental sheet metal Forming (SPIF) process. A L18 orthogonal array was designed using taguchi method for performing SPIF. The process parameters used were spindle speed, feed rate and vertical step down having three levels each and ball diameter having two levels. A straight groove test was conducted for 18 samples and strain based Forming Limit Diagrams (FLD) and stress based FLDs were plotted. Stress triaxiality and strain triaxiality were determined. The fractographs were analyzed and dislocation density was measured from x-ray diffraction line profile analysis. The corrosion behaviour of both undeformed sample and deformed sample were also studied. It was found that the formability is increased with increasing the spindle speed, decreasing the vertical step down and feed rate. The sum of strain was found to be 0.91 which is twice greater than that of conventional forming process. It is also found that the dislocation density is 2.35 times greater for the sample possesses higher formability than the sample possesses least formability. The goodness of fit in strain based FLD and stress based FLD are found to be 0.989 and 0.968 respectively.

Assessment of Enhanced Biological Phosphorus Removal Implementation Potential in a Full-Scale Wastewater Treatment Plant in Croatia

The objective of this study was to assess the possibility of retrofitting an existing full-scale wastewater treatment plant (WWTP) based on a sequencing batch reactor (SBR) technology with the enhanced biological phosphorus removal (EBPR) process. Wastewater characterisation showed highly variable influent composition that fluctuated throughout the year with a rather low and unstable SBOD/TP ratio (SBOD—soluble biological oxygen demand; TP—total phosphorus), which is considered unfavourable for EBPR. Characterisation of the sludge showed that the non-EBPR SBR sludge from the WWTP Koprivnica contained no detectable phosphorus accumulating organisms (PAO), but could be transformed in a laboratory into EBPR performing sludge in less than 45 days under favourable conditions for PAOs. The microbial community composition was assessed using an FISH (fluorescence in situ hybridization) analysis, which confirmed that the original sludge from the WWTP, which did not have detectable PAOs, was transformed into the sludge enriched by PAOs belonging to the genus ‘Candidatus Accumulibacter phosphatis’ after 43 days of cultivation. A plant retrofit, based on the results of laboratory experiments, was proposed with the enrichment of the wastewater with volatile fatty acids via primary anaerobic fermentation and step feeding. Results of mathematical modelling (BioWin) showed that such strategy could lead to sufficient P removal through EBPR in this WWTP.

Experimentation and FE simulation of single point incremental forming

One of the emerging flexible forming technologies in the sheet metal engineering is the incremental sheet forming, it uses universal tooling that is mostly part independent. Hence this process provide higher flexibility reducing the product development greatly and making it useful for low volume production. Single Point Incremental forming is drawing attention of the researchers & scientist all over the world because of the attractive characteristics. Like: improved formability, elimination of die & conventional press and ease of operation on general purpose Vertical Machining Centre. As this way of creating sheet metal formed products is in development stage, the factors affecting this needs comprehensive investigations.In this paper experimental and numerical investigation of formability of Aluminium 8011 alloy are presented and compared by preparing a conical frustum shape using SPIF process. The complete process is simulated using CATIA manufacturing simulation model to generate the path of Hemispherical end tool tip. Numeric Control (NC) part program is generated with the help of this simulated path to form the sheet into conical frustum shape on CNC mill machine. Four process parameters viz. vertical step depth, feed rate, spindle speed and angle of cone are chosen for the experimental investigations keeping height of the cone and material sheet thickness constant. Temperature, thickness reduction, strain and machining time are selected as a response variable. Optimizations are performed using TAGUCHI and ANOVA while the numerical study of the process is performed through ANSYS workbench software to predict stress, strain, temperature and thickness Results of experiments and numerical study are in close accord.

Experimental investigation on single point incremental forming of IS513Cr3 using response surface method

Abstract Sheet metal processing methods have evolved over time with the advancement in their applications and workability. The Incremental sheet forming method under study is an emerging technique of forming the sheet metal in which a single point tool is made to move on the sheet metal as per the predefined program. The motion of the tool with respect to the program produces desires complexities in the sheet metal. The present work focuses on understanding the material behavior of IS513 Cr3 sheet metal when subjected to incremental forming characterized with various parameters like step angle, tool material, feed and spindle speed. Analysis of variance test (ANOVA) is performed to find the effect of step depth and tool diameter on the surface roughness and formability. Finally, optimal comparisons have been made to understand the effectiveness of the process. The effect of forming at high feed rates and tool rotational speeds are studied and results are tabulated. In addition, the response surface method (RSM) analysis is done on the IS513 Cr3 sheet to understand its behavior and property modulations. The hardness of the sheet metal surface in each of the incrementally formed samples are also investigated and the corresponding results are studied.