Blown Film Extrusion Process for Polybags: Technical Overview and Applications

The choice of extrusion process is a decisive factor that affects the finished product quality for polybag manufacturing. One important component influencing the quality of the finished product is the selection of the extrusion technique. Two popular procedures that vary in the kind of dye used and the final product’s texture are cast film and blown film. In the horizontal extrusion moulding method known as “cast film”, heated resin is injected into a flat dye and allowed to cool on chill rolls. The film produced is clear, lightweight, and appropriate for lamination;its thickness varies based on the winding speed and the film is slower to crystallize and has less clarity but more durability because the resin molecules have reoriented, facing limitation of high wastage generation. This study primarily focused on the preparation of polybag film using the blown film extrusion process, utilizing high-quality polymer resins such as polyester polyethylene (PP) and linear low-density polyethylene (LLDPE) to minimize waste generation. The novelty of the process was reflected in minimising the waste generation. The control parameters considered in this study are temperature, pressure, and air intake volume. We investigated the influence of these critical process control parameters on the gauge thickness, optical properties, and mechanical strength of the polybag film produced through blown film extrusion. Additionally, we replicated the blown film process using simulation software developed at Pennsylvania College of Technology. The simulation results confirmed the overall stability of the polybag film produced through the blown film extrusion process.

A Unique Modelling Strategy to Dynamically Simulate the Performance of a Lobe Pump for Industrial Applications

The performance of a newly designed tri-lobe industrial lobe pump of high capacity is simulated by using commercial CFD solver Ansys Fluent. A combination of user-defined-functions and meshing strategies is employed to capture the rotation of the lobes. The numerical model is validated by comparing the simulated results with the literature values. The processes of suction, displacement, compression and exhaust are accurately captured in the transient simulation. The fluid pressure value remains in the range of inlet pressure value till the processes of suction and displacement are over. The instantaneous process of compression is accurately captured in the simulation. The movement of a particular working chamber is traced along the gradual degree of lobe’s rotation. At five different degrees of lobe’s rotation, pressure contour plots are reported which clearly shows the pressure values inside the working chamber. Each pressure value inside the working chamber conforms to the particular process in which the working chamber is operating. Finally, the power requirement at the shaft of rotation is estimated from the simulated values. The estimated value of power requirement is 3.61 BHP FHP whereas the same calculated theoretically is 3 BHP FHP. The discrepancy is attributed to the assumption of symmetry of blower along the thickness.

Effect of Red Mud (RM) Reinforcement on Physio-Chemical Characteristics of Ordinary Portland Slag Cement (OPSC) Mortar

The investigation focuses on evaluating the effect of varying % of Red Mud (RM) reinforcement with Ordinary Portland Slag Cement (OPSC). Characterisation is done by adding 10%, 20%, 30%, 40% and 50% of RM by weight to OPSC. RM + OPSC composite mortars are made in an 8.5 × 5 × 4 cm3 cast iron mould with external vibration keeping water-binder ratio 0.4 by weight. The mortars are cured in water for 28 days and their physio-chemical characteristics are investigated. Mortar performances like compressive strength, hardness, XRD, FTIR, SEM are diagnosed. The composite mortars cementing properties are compared with original OPSC. The result reveals the augmentation of RM with OPSC increases the hydration capacity of OPSC with improved compressive strength. The experimental optimization shows a maximum value up to 10% - 20% OPSC can be replaced by RM as filling material.

Sliding Wear Performance Evaluation of Red Mud (RM), RM + Fly Ash (FA) and RM + FA + Al Coatings on Mild Steel

The research paper focuses on evaluating the dry sliding wear behaviour of plasma sprayed coatings like red mud (RM), RM + 5% Fly Ash (FA) and RM + 5% FA + 5% Al on mild steel cylindrical shape substrate. Spraying was done at 10 kW operating power level. A conventional pin on disc wear tester is adopted for wear analysis. The wear test was performed at track diameter of 50 mm and sliding speed of 60 rpm (0.157 m/s) with normal load of 10 N. The duration of sliding varies from 54 minutes for pure red mud coating to a maximum value of 102 minutes for RM + 5% FA + 5% Al composite coating. A significant decrease in wear rate (in terms of mass loss) is observed by reinforcement of fly ash and aluminium to red mud, which might be due to improved interfacial properties.

Mechanical, Thermal and Crystallization Properties of Polypropylene (PP) Reinforced Composites with High Density Polyethylene (HDPE) as Matrix

Our work aims to evaluate a complete outlook of virgin high density polyethylene (HDPE) and polypropylene (PP) polyblends. Virgin PP of 20, 30 and 50 weight% is compounded with virgin HDPE. The properties like tensile strength, flexural strength, Izod impact strength are examined. Scanning electron microscopy (SEM) and polarised light microscopy (PLM) are used to observe the surface and crystal morphology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) tests verify the non compatibility of both polymers. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques are used to study the thermal behaviour of composites. The results manifest co-occurring spherulites for polyblends;indicating the composite to be a physical blend of continuous and dispersed phases, but on the other hand PP improves the tensile and flexural properties of HDPE.

Mixing and Segregation Characteristics of Binary Granular Material in Tapered Fluidized Bed: A CFD Study

The particle flow pattern, mixing and granule segregation in a tapered fluidized bed have been studied along with the hydrodynamics. At first the bed of varying total mass and granule fractions is fluidized then the bed is defluidized to freeze the composition, the bed is sectioned to layers and the composition in each layer is determined by sieving. Materials used in the present study are dolomite and glass beads with different B.S.S Sizes. A series of unsteady, three fluid CFD simulations were performed using FLUENTTM 6.2. Simulation parameters viz. solution technique, grid, maximum packing fraction and operating conditions like gas velocity were investigated for relative effects on particle mixing and segregation. Good arrangement of solid volume fraction profile was obtained between the experimental results and simulation results for regular particles.

Thermal Decomposition Behavior and Kinetic Study of Jamadoba Coal and Its Density Separated Macerals: A Non-Isothermal Approach

This kinetic study focuses on determining the thermal gravimetric profile of a particular grade of Indian sub-bituminous coal. A thermogravimetric analyzer (TGA-1000) was employed to investigate the thermal behavior and extract the kinetic parameters of Jamadoba coal and its corresponding density separated macerals. The weight loss was measured in air atmosphere. The coal samples used in this study were obtained from Jamadoba mines, Jharkhand. Samples of 35 mg and 200 μm mean size were subjected to synthetic air atmospheres (21% O2). Heating rates of 2, 5 and 7°C/min were applied until the temperature reached 1400°C, which was kept constant until burnout. Low heating rate was preferred so that devolatilization occurs prior to ignition and combustion. Derivative thermogravimetry (DTG) analysis method was applied to measure the weight changes and rates of weight loss used for calculating the kinetic parameters. The activation energy (Ea) and pre-exponential factor were obtained from model-free methods by applying non-isothermal thermogravimetry analysis.

Morphology and solid particle erosion wear behavior of red mud composite coatings

In order to understand the tribological behavior of red mud composite coatings, the red mud and composite materials like fly ash, carbon and aluminum are being plasma sprayed. The coatings are investigated to know their morphological behavior and erosion wear characteristics. Plasma spraying is done at different plasma arc current like 200, 250, 300 and 400 amperes. Torch input powers maintained as 6, 9, 12 and 16 KW. The substrates chose are rectangular in shape having a dimension of 50 mm × 25 mm × 2 mm. commercially available aluminum, copper, mild steel and stainless steel being used as substrate. Room temperature solid particle erosion trials are carried out using a compressed air blasting type rig under impact angles of 30o, 60o and 90o. The present investigation uses an erosion apparatus of Sand Blast type. The test is conducted as per ASTMG-76 standards. It is analyzed that initially the cumulative coating mass loss increases rapidly and later on becomes almost stagnant. A transient regime in the erosion process exists, during which the incremental erosion rate decreases monotonically down to a steady state erosion rate.

Wettability, Thermal and Sliding Behavior of Thermally Sprayed Fly Ash Premixed Red Mud Coatings on Mild Steel

The present experimental work reveals the surface characteristics like wettability, thermal and sliding wear behaviour of plasma-sprayed red mud (RM) coatings premixed with fly ash (FA). Varying weight % of FA (10, 20, 30 and 40)—RM composite powder is used as precursor for coating. Atmospheric plasma-sprayed coatings are developed at different operating power like 5 kW, 10 kW, 15 kW and 20 kW separately on mild steel substrate. Tribological behaviour viz. sliding wear properties are studied at distinct operating load (10N, 15N, 20N, 25N), speed (40 rpm, 50 rpm, 60 rpm, 70 rpm) and track diameter of 100 mm using a pin on disc tribometer for duration of 30 minutes with 3 minute gap period for each experiment. The DSC and TGA experiments of the coatings are performed to understand the high temperature application areas. The contact angle result signifies the wettability of the prepared coatings is principally a function of composition. The reaction of surface roughness and spraying power is in-significant on water contact angle (WCA). In conclusion, the sliding wear experiments are optimized by Taguchi method to ascertain the influencing parameter on wear.

Experimental Investigation and Process Optimization of Biodiesel Production from Kusum Oil Using Taguchi Method

The paper focuses on biodiesel production from kusum oil using esterification reaction followed by transesterification reaction in an in-house batch reactor setup. The effects of methanol to oil ratio (M/O), catalyst amount (H2SO4 and methodoxide) and reaction temperature on acid value and fatty acid methyl esters (FAME) is studied. Product has been analysed using FTIR spectroscopy technique for confirmation of ester group in biodiesel. Experimental data was optimized by Taguchi analysis to conclude the optimum variable affecting the response. In both processes M/O ratio has the significant effect for biodiesel production. The obtained biodiesel properties are close to commercial diesel fuel and may be rated as an alternative to conventional diesel. The biodiesel production will enhance the maximum utilisation of forestry or agricultural products.

Strain Rate Effects on Tensile Properties of HDPE-PP Composite Prepared by Extrusion and Injection Moulding Method

The present paper investigates the effect of strain rate on different tensile properties of high density polyethylene (HDPE) and polypropylene (PP) composite. Tensile specimens of virgin HDPE-PP composites are prepared via twin screw extruder and injection moulding methods as per ASTM D638-02a (Type-I);with gage length 50 mm, width 13 mm and thickness 3 mm. Composites are fabricated with PP as reinforcing agent at a loading rate of 10%, 20%, 30%, 40% and 50% by weight. Experiments are carried out at room temperature of 23°C and absolute humidity of 54% at a cross head speed of 30, 40, 50, 60 and 70 mm/min. Stress and strain values at yield and break points are reported. Atomic force microscopy (AFM) is used to study the distribution of polymer molecules in the mixture and surface roughness. As in last, experiments are designed by Taguchi optimization method to find out the dominating factors on tensile strength.

Electrical Behaviour and Spherulites Morphology of HDPE/PP Polyblends with HDPE as Base Material

Polymer composites of virgin high density poly ethylene (HDPE) and virgin polypropylene (PP) are prepared. PP of weight% of 20, 30 and 50 are reinforced to HDPE in the form of pellets. They are converted into raw polymer sheets using a two roll milling machine. The prepared raw sheets have undergone compression moulding to fabricate polymer sheets to study electrical properties like dielectric strength, surface resistivity and volume resistivity at atmospheric temperature and pressure. Result shows dielectric strength and volume resistivity decreases with addition of PP to HDPE, whereas surface resistivity increases. Crystal growth rate is observed using a cross polarised microscope (PLM). The microscopy results reveal, the PP crystallizes faster than HDPE and the growth rate declines for the polyblend;showing non-uniform and hazy spherulitic structure.

Optimization of Raceway Parameters in Iron Making Blast Furnace for Maximizing the Pulverized Coal Injection (PCI) Rate

This paper presents a method by which the maximum possible rate of pulverized coal injection (PCI) in blast furnace can be predicted. The method is based on a two-step approach. First, a first principle simulation model of the blast furnace is used to generate data sets for the development of a linear model of pulverized coal injection rate. The data has been generated randomly in MATLAB software within the range of operating parameters (constraints) of the blast furnace. After that, the coefficients of the function have been determined. The inputs and the resulting outputs formed the data on which the linear optimization model was developed. Next, the linear model was used for maximizing the pulverized coal rate injection by optimizing the other variables. Two operating Indian Blast Furnaces have been chosen to validate the optimization model.