Strategies to Form Homogeneous Mixture and Methods to Control Auto-Ignition of HCCI Engine

Homogeneous charge compression ignition (HCCI) engine has emerged as a promising combustion technology. Theoretically, an HCCI engine can reduce both NOx and soot emissions significantly down to almost zero levels. This is possible as a result of two fundamental processes that occur in the HCCI engine, i.e. the homogeneous mixture and its autoignition characteristics. Neither spark plug nor injector is used in the HCCI engine. The autoignition of the homogeneous mixture is solely influenced by its chemical reactions inside the combustion chamber. However, this is where the problems start to occur. At low loads or too lean mixtures, misfire may occur, thus increasing the HC and CO emissions. At high loads or too rich mixtures, soot emissions and knocking tendency may increase. Moreover, an undesirable pressure rise due to knocking will increase the combustion temperature and potentially increase the probability of NOx formation. Therefore, the operating range of HCCI engine is very limited only to part loads. Controlling its combustion phasing play an important role to extend the narrow operating range of the HCCI engine. Despite numerous review articles have been published, classification of the approaches to achieve HCCI combustion in diesel engines were rarely presented clearly. Therefore, this review article aims to provide a concise and comprehensive classification of HCCI combustion so that the role and position of each strategy found in the literature could be understood distinctively. In short, two important questions must be solved to have successful HCCI combustion; (1) how to form a homogeneous mixture? and (2) how to control its auto-ignition?

Mechanical and Durability Characteristics of Eco-Friendly Fly Ash Bricks

This paper presents an experimental investigation carried out on eco-friendly fly ash bricks having various percentage of fly ash, lime, gypsum, stone dust, coarse aggregate and boiler slag. Raw materials are added to the pan mixer with different mix proportions and are mixed thoroughly with water until a homogeneous mixture is formed. Prepared homogeneous mixture is fed into the press and moulded to a brick of size 200 x 200 x 300 mm using vibro-hydraulic press. Moulded bricks are air dried for 24 hours, arranged in stacks and are cured for a period of 28 days by sprinkling the water to achieve the optimum strength. Compressive strength, water absorption, efflorescence, dimension tolerance and density tests are conducted as per BIS codal provisions. Eco friendly fly ash bricks having varying proportions of industrial by-products with less content of stone dust satisfy compressive, water absorption, efflorescence, dimensional tolerance and density requirements as per BIS codal provisions and can be used in structures as a sustainable construction material. Keywords: Eco-friendly fly ash bricks, Compressive strength, Water absorption, Efflorescence, Dimension tolerance and Density

Fabrication Of Lithium-Carbon Composite Material From Pepper Peel Waste As Battery Electrodes

The manufacture of battery cathode electrodes made of LiFeO4 and activated carbon from pepper peel has been successfully carried out. The electrodes were made using the soli state reaction method with the addition of adhesives in the form of PVdf and NMP. The resulting homogeneous mixture is then placed in a mold and dried in an oven at 90° to dry to form sheets. The dried electrode sheets were then characterized using FTIR and tested for conductivity values using EIS. The FTIR results showed that there was no change in the functional group with the addition of carbon mass. Meanwhile, the results of the conductivity test showed that the optimum conductivity value occurred in the sample with the addition of 10% carbon mass is 7.42 × 10-4 S/cm.

DEVELOPMENT SODIUM ALGINATE SODIUM BICARBONATE CALCIUM CARBONATE ORAL SUSPENSION USING TURBISCAN TOWER AND ZETA POTENTIAL

Sodium Alginate Sodium Bicarbonate Calcium Carbonate combination reduces heartburn, heartburn or stomach complaints caused by reflux. The aim of this study is to create sodium alginate sodium bicarbonate calcium carbonate combination formulation using pre-development devices such as Turbiscan Tower and Zeta Potential. In order to obtain a homogeneous mixture during production and pilot study using two different boiler 5 trial production, samples will be pre-feasibility devices (Turbiscan Tower and Zeta Potential) stress conditions using physical behaviors have been observed.

RANCANG BANGUN MESIN PENGADUK SABUN CUCI CAIR UNTUK MENGOPTIMALKAN WAKTU PRODUKSI PADA INDUSTRI RUMAH TANGGA

Indonesia's economy during the second quarter of 2020 getting a contraction about 4.19 percent, due to the COVID-19 pandemic. This decline has an impact on the economic sector, one of which is MSMEs which contribute 15.75 percent annually to economic growth. Liquid soap is one of the MSMEs products that needs improvement because of this impact. This research was purposed to develop the process of mixing liquid soap ingredients with an electric-powered stirrer machine to obtain a constant mixing process, and produce a homogeneous mixture of liquid soap. The results of this research succeeded in making a liquid soap mixer machine using “L” shape plate frame with dimensions of length x width x height about 610 x 530 x 900 mm. The power of the stirrer machine about 0.25 HP using an electric motor, with rotation speed of 1400 rpm on electric motor and 343.4 rpm on stirrer, and produces a torque for stirring the concentrate of liquid soap about 3.42 N.m. The results of the production of liquid soap with the machine show an increased in production time about 30.9%, and the product have characteristics of a thicker liquid soap, than manual production, for the same production volume.

Experimental Investigation of Large Particle Slurry Transport in Vertically Oscillating Pipe for Subsea Mining

For subsea mining, it is important to predict the pressure loss in oscillating pipes for the safe and reliable operation of ore lifting as well as the design of lifting system. In the present paper, the authors focused on the internal flow in vertical lifting pipe oscillating in the axial direction and carried out slurry transport experiment to investigate the effects of pipe oscillation on the pressure loss. The spherical alumina beads and glass beads were used as the solid particles in the experiment, and the oscillating periods and amplitudes of pipe model as well as the solid concentrations and the mean slurry velocities were varied. The time-averaged components of hydraulic gradient calculated by the prediction method for the steady flow proposed in the past by the authors agreed well with the experimental ones. As for the fluctuating components of hydraulic gradient, the calculation results using a homogeneous mixture model were compared with the experimental data. The comparison result indicated that the homogeneous mixture model would be applicable to the prediction of pressure loss in the vertical pipe oscillating in the axial direction.

Investigation of the Use and Suitability of Plastic Waste for Molding Interlocking Stones in Port Harcourt

Port Harcourt is known in local parlance as the ‘Garden City’ of Rivers State. This is so tagged because of the overwhelming presence of trees (Green Life) and flowers in the Metropolis. But today, it is different as the streets, gutters, rivers and the environs are littered with all types of plastic waste (MSW). These municipal solid wastes (MSW), are indiscriminately dumped at different locations in the Garden City. Plastics constitute a major component of these wastes; thus, this study was aimed at Investigating the Use and Suitability of plastic waste for molding Interlocking stones in Port Harcourt. In this study, samples of plastic wastes (bottles, cups, plates, spoons, and cellophane bags), were collected randomly at selected locations in Port Harcourt City. The area of study covered GRA Phase 1, 2, and 3, Old GRA, Diobu axis, and Port Harcourt main town. These plastic wastes are (PET-Polyethylene Terephthalate) which after collection were weighed and mixed with fine grains of sand (4 kg). The plastic waste samples of 5, 10 and 15 kg were used to mix with fine grains of sand of 4 kg. The mixture was heated under very high temperatures and melted to form a homogeneous mixture. The resultant homogeneous mixture was then poured into different molds of the same sizes (1.32 x10-3 M3). In another reaction, fine grain of sand of 4 kg was mixed with cement of 5, 10 and 15 kg respectively. The mixtures were poured into molds of the same sizes (1.32 x10-3 M3). The strengths of the two different interlocking stones (paver) were measured and compared to confirm which one of them has a better compressive strength for 7, 14 & 28 days. A total of fifty-four (54) molds were used of which twenty-seven were made from plastic waste and the other twenty-seven from cement. The compressive strength of Interlocks made from the two substances were measured and compared. The result showed the compressive strength of Interlocks made from 5, 10 and 15 kg of plastic wastes and 4 kg of sand for 7, 14, and 28 days being comparable to that of cement. The t-test showed that there is no significant difference between the strength of mold made by cement and that of plastic waste. This implies that Plastic Wastes can act as a suitable alternative material to cement for the making of interlocking stones as it has excellent binding properties like cement. This study recommends proper management and disposal of wastes to reduce environmental degradation.

Detailed Numerical Comparison of Laminar Burning-Speed of Stratified Hydrogen-Air and Methane-Air Mixture with Corresponding Homogeneous Mixture Using Open-Source Code

Detailed numerical study of laminar burning speed for fuel-air mixture is conducted using laminarReactingLMFoam solver which is a modified version of reactingfoam solver based on OpenFoam code. It accounts for detailed mixture averaged transport property calculation for reacting flow using low-Mach number governing equations. Effect of various equivalence ratio gradients is studied on stratified hydrogen-air and methane-air mixture with mixture-averaged transport model and unity Lewis number for all species and corresponding laminar burning speed is compared with homogeneous mixture. For both the fuel-air mixture, rich to lean stratified mixture resulted in a higher laminar burning speed and no significant difference was noticed for lean to rich stratified mixture when compared to homogeneous mixture at same local equivalence ratio. Increased burning speed is explained based on higher burnt gas temperature and molecular diffusion of lighter species from burnt gas referred to “Chemical Effect” in this study. Effect of thermal and molecular diffusion from the burnt gas on laminar burning speed is studied for stratified and homogeneous mixture using mixture-averaged transport model and unity Lewis number for all species. It is shown that molecular diffusion effect from burnt gas (“Chemical Effect”) are more prominent as compared to thermal diffusion effect. Extension in lean flammability limit for stratified mixture of both the fuel is shown based on higher heat release rate as compared to homogeneous mixture and extension in flammability limit for stratified mixture is explained based on higher Chemical Effect from burnt gas.