Improper disposal of waste plastic contributes significantly to environmental pollution. A promising solution to address this issue involves converting such plastics into valuable lubricating oils. This study investigated the tribological performance of both an aromatic-lean industrial plastic oil (PO) and aromatic-rich lab-scale plastic oils (LPO) using a ball-on-disk setup. The results revealed that PO exhibited considerably higher coefficients of friction (COF) and specific wear rates compared to LPO. To enhance the lubrication performance, a bio-based ionic liquid (IL: trihexyltetradecyl phosphonium saccharinate) with an unsaturated anion was incorporated. The COF and wear rates were further reduced with an IL blend in both PO and LPO. The IL additive promoted increased film thickness, beneficial micelle formation, facilitated adsorption film formation, and provided a phosphorus-rich tribofilm. These mechanisms collectively contributed to the notable improvement in tribological performance. Overall, this research demonstrates the potential of IL additives to enhance the tribological performance of both PO and LPO, thereby mitigating waste plastic pollution, and fostering a sustainable future. 

As-built additively manufactured components for heat exchanger applications, suffer from high surface roughness. In this study, a novel ultrasonic-assisted electropolishing setup is designed and tested to reduce the internal surface roughness of a Laser Powder Bed Fusion (L-PBF) additively manufactured copper (GRCop-42) heat exchanger component. In the electropolishing setup, the surface of the as-built heat exchanger is used as the anode while a bulk copper rod is used as the cathode. An electropolishing fluid consisting of CuCl2, HCl, and SiC abrasive particles was used as electrolyte media, along with ultrasonication. The effect of chemical constituents, ultrasonic duration, and abrasive particles on surface roughness reduction was studied. It was observed that the ultrasonic agitation condition assisted with the abrasive particles was beneficial to reduce the surface roughness of the heat exchanger sample (over 50%) through acoustic streaming and scrubbing effect. An addition of 1% bio-based trihexyltetradecyl phosphonium saccharinate ionic liquid improved the corrosion properties for the copper surface. Overall, to reduce the roughness of L-PBF additively manufactured samples of complicated shapes with internal features, this process could be a viable technique, where mechanical polishing is not possible and internal surfaces are not accessible. 

This study examined six phosphonium-based room-temperature ionic liquids (PRTILs) having trihexyltetradecyl- or tributyltetradecyl-phosphonium cations with saccharinate, salicylate, or benzoate anions, and obtained a feature parameter to correlate their cationic chain length, anionic ring size, and contact angle with tribological properties. PRTILs with trihexyltetradecyl-phosphonium cations had lower coefficient of friction (COF) and wear than PRTILs with tributyltetradecyl- phosphonium cations, a trend attributed to the additional methylene groups providing lower contact angle. For either cation, PRTILs with the saccharinate anion exhibited much lower COF and wear than single-ring anions, due to the formation of a low-shear-strength-tribofilm facilitated by the double-ring structure and sulfur of saccharinate. Overall, this study revealed PRTIL interfacial mechanisms that can be used to identify anion-cation combinations with optimal tribological performance. 

Experiments and simulations were used to investigate interactions between ferrous surfaces and trihexyltetradecylphosphonium benzoate or salicylate. Differences between the ionic liquids were observed in open circuit potential, potentiodynamic polarization, cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and long-duration corrosion tests. While both ionic liquids were far less corrosive than water, salicylate exhibited slower charge transfer and lower surface protection potential than benzoate. These observations were analyzed using simulations of chemical reactions between ions and an ideal Fe(100) surface. Simulation results showed that salicylate and benzoate differed in their bonding configurations and orientations, suggesting distinct adsorption mechanisms for these similar ionic liquids. 

Pyrolysis is a viable thermochemical conversion (TCC) process to convert waste plastics into useful chemicals and alternative energy. Specifically, co-pyrolysis of plastics with biomass produce gasoline and diesel range hydrocarbons, aromatics, olefins, lubricants, and other valuable chemicals. Lignocellulosic biomass often produces low-quality fuel through pyrolysis, which could be improved by adding plastics as a co-feedstock. Plastics improve the hydrogen-to-carbon effective (H/Ceff) ratio in the feedstock and donate protons (H+) in the reaction mechanism. More petrochemicals (aromatics and olefins) and gasoline with less coke could be generated if a higher H/Ceff ratio is obtained in the feedstock. H+ proton can reduce oxygenated compounds and produce aromatics. Besides, high temperature (above 600 °C) promotes cyclic hydrocarbons, aromatics, coke formation, and dewaxing mechanism. Cyclic hydrocarbons and aromatics could be useful to improve plastic pyrolysis oil tribology. Washing and sizing waste plastics before pyrolysis is important for the desired yield. Also, the operating temperature, zeolitic and non-zeolitic catalysts and reactor types play important roles in obtaining specific product types. This research summarizes the pyrolysis of individual and mixed plastics using state-of-the-art literature and summarized their dewaxing and pyrolysis mechanisms. Besides, the co-pyrolysis of plastics and biomass along with their reaction mechanism is summarized. The future direction to utilize plastic pyrolysis for space exploration is also highlighted. 

In this study, plastic oil (PO) as a potential lubricant was investigated. The base PO was incorporated with graphene nanoplatelets (GNP) and hexagonal boron nitride (hBN) nano additives in varying concentrations to form nano lubricants. Their viscosity, tribological, acidic/basic nature, thermal degradation and dispersion stability properties were investigated. It was observed that 1.5 wt% GNP and 1.0 wt% hBN added separately to the base PO, provided the lowest coefficient of friction (COF) and wear volume. Based on these lowest COF and wear volume insights, three nano lubricant mixtures were formulated by incorporating both GNP and hBN at different combinations using base PO. Positive synergistic behaviour was observed for COF (49%–60% reduced) and wear volume (90%–97% reduced) for two combination mixtures compared to the base PO. These improvements in the mixture were due to the polishing, mending mechanisms and tribofilm that protected the interacting surfaces. 

Machine learning (ML) algorithms have brought about a revolution in many industries where otherwise operation time, cost, and safety would have been compromised. Likewise, in lubrication research, ML has been utilized on many occasions. This review provides an in-depth understanding of seven ML algorithms from a tribological perspective. More specifically, it presents a comprehensive overview of recent advancements in ML applied to lubrication research, organized into four distinct categories. The first category, experimental parameter prediction, highlights the significant contributions of artificial neural networks (ANNs) in accurately forecasting operating conditions related to friction and wear. These predictions offer valuable insights that aid in forensic preparation. Discriminant analysis, Bayesian modeling, and transfer learning approaches have also been used to predict experimental parameters. Second, to predict the lubrication film thickness and identify the lubrication regime, algorithms such as logistic regression and ANN were useful. Such predictions provide up to 99.25% accuracy. Third, to predict the friction and wear for a given experimental condition, support vector machine (SVM), polynomial regression, and ANN offered an accuracy above 93%. Finally, for condition monitoring for bearings, gearboxes, gear trains, and similar critical situations where regular in-person inspection is difficult, Naïve Bayes, SVM, decision trees, and ANN were utilized to predict the safe life of lubricants. This review highlighted these four aspects with state-of-the-art examples and discussed the current situation and projected future possibilities of lubricant design facilitated by ML techniques. 

To achieve superior tribological performance without continuous lubricant supply, a novel ceramic - phosphonium based ionic liquids (P-ILs) system is developed via vacuum impregnation. The P-ILs with different viscosity and density impregnated in ceramic pellets were tested at different temperatures and sliding velocities. The results suggest that at a low temperature of 5 °C, the phosphonium benzoate and phosphonium salicylate IL exhibited a low coefficient of friction (COF) than the phosphonium saccharinate IL under a sliding velocity of 100 mm/s. Whereas this trend reversed at a higher temperature of 50 and 100 °C. Similar observations were also made for the wear rate of this unique system. It was found that the tribological performance of the P-IL+ceramic system depends on the thermal response of these ILs which is further correlated with the density and viscosity of P-ILs that control the supply of lubricants at the sliding interface.

The friction and wear behavior of bio-based trihexyltetradecylphosphonium saccharinate [P6,6,6,14][Sacc] and halogen-based trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) amide [P6,6,6,14][NTF2] ionic liquids (ILs) were studied to understand their lubrication mechanisms at steel sliding interfaces. The physicochemical and tribological properties of the ILs were characterized over a wide temperature range (10–120 ℃) to reflect the conditions present in wind turbine applications. Friction increased with increasing temperature for both ILs. At any temperature, [P6,6,6,14][Sacc] had significantly higher viscosity that provided thicker lubricant films and, in turn, better friction and wear protection than the halogen-based [P6,6,6,14][NTF2]. [P6,6,6,14][Sacc] also had lower density, comparable thermal stability, more favorable wettability, and better corrosion performance than [P6,6,6,14][NTF2]. Simulations showed that the cohesion interaction energy was stronger for [P-Sacc] due to its smaller anion-cation distance. The higher viscosity and stronger cohesion of [P6,6,6,14][Sacc] than [P6,6,6,14][NTF2] contributed to the ability of the bio-based IL to form an effective adsorption film that reduced friction and wear across a range of temperatures.

Phosphonium-based room temperature ionic liquids (P-RTILs) offer outstanding lubricant properties. Studies have shown that the cationic chain length and anionic ring size significantly affect the performance of P-RTIL lubricants by altering properties, such as viscosity, density, thermal stability, wettability, and solubility. Functionalized moieties further improve their performance. However, the presence of halide groups could introduce corrosion and toxicity, which could be minimized by non-halide anions with large alkyl-chain-carrying cations to optimize both corrosion and tribological performance of P-RTILs. In this review, state-of-the-art research of P-RTILs is summarized from the lubrication perspective, covering their synthesis, properties, lubricant-relevant mechanisms, and performance matrices. Finally, the potential for developing a circular economy enabled by the biodegradability, recovery, and alternative applications of P-RTILs is discussed.

Phosphonium-based room temperature ionic liquids (P-RTILs) offer outstanding lubricant properties. Studies have shown that the cationic chain length and anionic ring size significantly affect the performance of P-RTIL lubricants by altering properties, such as viscosity, density, thermal stability, wettability, and solubility. Functionalized moieties further improve their performance. However, the presence of halide groups could introduce corrosion and toxicity, which could be minimized by non-halide anions with large alkyl-chain-carrying cations to optimize both corrosion and tribological performance of P-RTILs. In this review, state-of-the-art research of P-RTILs is summarized from the lubrication perspective, covering their synthesis, properties, lubricant-relevant mechanisms, and performance matrices. Finally, the potential for developing a circular economy enabled by the biodegradability, recovery, and alternative applications of P-RTILs is discussed.

Abstract: The overall objective of this study is to develop a novel two-staged fixed-bed reactor to evaluate the catalytic pyrolysis of recyclable (HDPE) and compostable waste plastics and to enhance the selectivity of gasoline range hydrocarbons in pyrolysis liquid. In this research, both used and unused compostable bioplastics, recyclable high-density polyethylene (HDPE) grocery bags, and unused HDPE were used as a feedstock Additionally, a mixture of recyclable plastic and compostable bioplastic with 1:1 ratio was pyrolyzed at 500 °C, and the pyrolysis oil products were compared with commercial gasoline. Zeolite Socony Mobil-5 (ZSM-5) was used as a catalyst in all the catalytic pyrolysis experiments, which produced wax-free shorter chain hydrocarbons similar to commercial gasoline. The addition of recyclable HDPE in compostable plastics improved the selectivity of gasoline range hydrocarbon () by 10% and increased the calorific value of pyrolysis liquids by 7.5% (43 MJ/kg), which is equivalent to commercial gasoline. Moreover, both compostable and recyclable plastics produced aromatic and aliphatic hydrocarbons that have potential applications in lubricants, additives, and petrochemical industries.

Abstract: The thermal stability of ionic liquids is important for their use in a variety of applications. Here, reactive molecular dynamics simulations and thermogravimetric analyses were used to explore the thermal decomposition mechanisms of phosphonium salicylate and phosphonium benzoate. Experiments performed at different heating rates indicated that the decomposition temperatures of phosphonium salicylate and phosphonium benzoate were comparable, but phosphonium benzoate was less stable than phosphonium salicylate under isothermal high temperature conditions. The lower thermal stability of the benzoate compared to the salicylate was reproduced in reactive molecular dynamics simulations. The simulations also showed that cation chain length had little effect on thermal stability. The simulations revealed that thermal decomposition for both phosphonium salicylate and phosphonium benzoate occurred through many different pathways that could be broadly categorized as proton-transfer, association, and dissociation reactions. The phosphonium benzoate underwent more of these reactions and exhibited a wide range of reaction pathways in each category than the phosphonium salicylate. Multiple possible mechanisms were explored to explain this difference and it was found that the dominant factor was the presence of the hydroxyl group in salicylate that affects the ability of oxygen atoms to take part in proton-transfer reactions that are the first step of all subsequent reactions. These findings demonstrate that even subtle differences in anion chemistry may significantly affect the thermal stability of ionic liquids, suggesting avenues for tuning these properties through molecular design.

Abstract: The wettability of ionic liquids (ILs) is relevant to their use in various applications. However, a mechanistic understanding of how the cation–anion pair affects wettability is still evolving. Here, focusing on phosphonium ILs, wettability was characterized in terms of contact angle using experiments and classical molecular dynamics simulations. Both experiments and simulations showed that the contact angle was affected by the anion and increased as benzoate < salicylate < saccharinate. Further, the simulations showed that the contact angle decreased with increasing cation alkyl chain length for these anions paired with five different tetra-alkyl-phosphonium cations. The trends were explained in terms of adhesive and cohesive energies in the simulations and then correlated to the atomic scale differences between the anions and the cations.

Abstract: In this work, the wear and corrosion behavior of high-pressure cold-sprayed (CS) 316 L stainless-steel (SS) was investigated and compared with traditional 316 L SS for pharmaceutical component repairing/refurbishing. It was observed that the CS deposit exhibited a compact microstructure with a greater percentage of the ferrite phase. The effect of CS also resulted in a refinement of crystallinity due to the localized adiabatic heating and stresses of the severely deformed particles. These effects translated to the reduced wear and friction observed from the CS deposit as it demonstrated a lesser degree of abrasive wear. Electrochemical tests also revealed that the CS sample had a relatively similar corrosion rate as the bulk sample with an enhanced re-passivation ability.

Small living organisms such as lizards possess naturally built functional surface textures that enable them to walk or climb on versatile surface topographies. Bio-mimicking the surface characteristics of these geckos has enormous potential to improve the accessibility of modern robotics. Therefore, gecko-inspired adhesives have significant industrial applications, including robotic endoscopy, bio-medical cleaning, medical bandage tapes, rock climbing adhesives, tissue adhesives, etc. As a result, synthetic adhesives have been developed by researchers, in addition to dry fibrillary adhesives, elastomeric adhesives, electrostatic adhesives, and thermoplastic adhesives. All these adhesives represent significant contributions towards robotic grippers and gloves, depending on the nature of the application. However, these adhesives often exhibit limitations in the form of fouling, wear, and tear, which restrict their functionalities and load-carrying capabilities in the natural environment. Therefore, it is essential to summarize the state of the art attributes of contemporary studies to extend the ongoing work in this field. This review summarizes different adhesion mechanisms involving gecko-inspired adhesives and attempts to explain the parameters and limitations which have impacts on adhesion. Additionally, different novel adhesive fabrication techniques such as replica molding, 3D direct laser writing, dip transfer processing, fused deposition modeling, and digital light processing are encapsulated.

Stereolithography (SLA) has become an important additive manufacturing technique nowadays. High-level accuracy, availability of a wide range of resin materials, and diversified applications from the medical industry to the prototyping sectors made SLA an efficient 3D printing process. Like other 3D printing processes, SLA printing also has the same three primary steps: design of the specimen, printing, and finally, postprocessing treatment. These steps are vital for creating prototypes and workpieces with desired mechanical, tribological, and corrosion properties. Typically, layer thickness, the orientation of the constructed piece, and the hatch spacing influence mechanical and tribological properties. In terms of corrosion and tribo-corrosion behavior, the addition of secondary substances, such as graphene, alumina, and zirconia, have been proven helpful to increase the conductivity, improve the strength of the material, and improve the texture for dental applications. Over the past decade, the SLA process has benefited rapid prototyping, preoperative planning, research, biocompatible organ printing, and many other engineering and biomedical applications.

Additive manufacturing (AM) is the process of creating an object by depositing materials in layer by layer to create a 3D object directly from a computer-aided design (CAD) model. One of the widely used AM methods is fused deposition modeling (FDM). FDM printers typically use a thermoplastic filament, which is heated until it melts and then extruded through a nozzle onto a platform. FDM is an important manufacturing process because it can create parts with good thermal and chemical resistance and strength to weight ratios, making it ideal for demanding applications. It is one of the most common methods and usually the cheapest, depending on the model. Additionally, FDM is an excellent option when designing a custom or complex part. FDM printing is an excellent solution for fast-track prototyping of accurate models but can also be used in a production environment. Along with the prints’ speed and accuracy, FDM printing can also be used for parts that need to be food safe by simply changing the material used. A common food-safe material is ABS-M30i. Therefore, FDM is useful in pharmaceuticals, biomedical, and implants applications. Overall, FDM manufacturing has been changing the way industrial parts, life-saving drugs can be made and how rapid prototypes can be created.

As the manufacturing industry continues to advance, functionally graded metallic materials (FGMMs) are becoming more important due to their unique properties and versatile applications. Conventional methods, such as casting, thermal spraying, and chemical vapor deposition, have been widely utilized to produce such FGMMs for long. In recent years, additive manufacturing techniques, such as material jetting and powder bed fusion, have been introduced to make FGMMs due to the practicality of the automated systems as well as the associated reduction in cost and materials. In this chapter, both conventional and additive manufacturing processes of FGMM have been presented, and their mechanical, tribological, and corrosive properties have been investigated. Finally, the applications of the introduced FGMMs have been portrayed in the context of medical, energy, and chemical industries.

Powder bed fusion is an additive manufacturing technology used to create functional industrial parts and complex 3D geometries, layer by layer, which are not feasible using traditional manufacturing techniques. This processing technique involves spreading a thin layer of powder over the build platform and selectively heating the powder using a heat source or laser to adhere the powders together. This process is repeated for each subsequent layer of powder to form the final product, thus eliminating the need for any complex tooling or fixtures. This chapter discusses the various commonly used powder bed manufacturing methods used in the industries such as selective laser sintering, selective laser melting, selective heat sintering, and direct metal laser sintering. These powder bed fusion techniques can cater to a wide range of materials, including polymers, composites, metals, and their alloys. The choice of the manufacturing method, material composition, process parameters, and post-treatment can offer customized and enhanced properties to these 3D-printed materials. In this chapter, the basic principle and operation of each method, the impact of their process parameters on obtained material properties, and recent applications of the powder bed processes are discussed.

Abstract: The overall goal of this research was to study the effects of temperature and pine-to-HDPE ratios on the pyrolysis products. Catalytic co-pyrolysis of pine and HDPE was carried out in a double-column staged reactor, wherein the temperature was varied as 450 °C, 500 °C, and 550 °C for each pine/HDPE ratio of 0/100, 25/75, 50/50, 75/25, and 100/0. Thermal cracking of the feedstock is initiated at the first column, and the zeolitic-based ZSM-5 catalyst offered secondary cracking at a catalyst-to-feedstock ratio of 1:1 in the second column of the reactor. Catalytic pyrolysis of HDPE produced 31 wt% pyrolysis oil (40 MJ/kg calorific value) with a selectivity of above 90% toward gasoline-range hydrocarbons at 500 °C. Comparatively, pine offered 26.3% wt.% pyrolysis liquid yield with 7.9% dark pyrolysis oil (30 MJ/kg calorific value) that has a gasoline selectivity of 69.3%. Thus, the addition of HDPE increased the gasoline selectivity by increasing the hydrogen/carbon effective (H/Ceff) ratio. At pine/HDPE ratio of 25/75, the pyrolysis oil content was 22.5% at 500 °C, which is 3 times more than that of pine pyrolysis. The optimum yield and higher gasoline selectivity were observed at 500 °C for 0/100 and 25/75 pine to HDPE ratios.

Abstract: Electroactive polymers (EAPs) are an advanced family of polymers that change their shape through electric stimulation and have been a point of interest since their inception. This unique functionality has helped EAPs to contribute to versatile fields, such as electrical, biomedical, and robotics, to name a few. Ionic EAPs have a significant advantage over electronic EAPs. For example, Ionic EAPs require a lower voltage to activate than electronic EAPs. On the other hand, electronic EAPs could generate a relatively larger actuation force. Therefore, efforts have been focused on improving both kinds to achieve superior properties. In this review, the synthesis routes of different EAP-based actuators and their properties are discussed. Moreover, their mechanical interactions have been investigated from a tribological perspective as all these EAPs undergo surface interactions. Such interactions could reduce their useful life and need significant research attention for enhancing their life. Recent advancements and numerous applications of EAPs in various sectors are also discussed in this review.

Water-based lubricants (WBLs) have been at the forefront of recent research, due to the abundant availability of water at a low cost. However, in metallic tribo-systems, WBLs often exhibit poor performance compared to petroleum-based lubricants. Research and development indicate that nano-additives improve the lubrication performance of water. Some of these additives could be categorized as solid nanoparticles, ionic liquids, and bio-based oils. These additives improve the tribological properties and help to reduce friction, wear, and corrosion. This review explored different water-based lubricant additives and summarized their properties and performances. Viscosity, density, wettability, and solubility are discussed to determine the viability of using water-based nano-lubricants compared to petroleum-based lubricants for reducing friction and wear in machining. Water-based liquid lubricants also have environmental benefits over petroleum-based lubricants. Further research is needed to understand and optimize water-based lubrication for tribological systems completely.

Abstract: In recent years, with the development of eco-friendly lubricants, different vegetable oils have been studied and found to improve the overall tribological performance compared to petroleum-based oils. Being one of the commonly used vegetable oils, canola oil has become popular due to its non-toxicity and low cost. However, this bio-lubricant lacks tribological performance compared to petroleum-based oils. To improve its performance, sustainable solid additives such as graphene nanoplatelet (GNP) and hexagonal boron nitride (hBN) have recently gained the researcher’s attention. While incorporating nanomaterials in the oil as additives is a promising way to improve base oil’s performance, the excessive use of nanoparticles can introduce undesirable effects. This study investigated canola oil’s tribological performances with the addition of 0.5, 1.0, 1.5, and 2.0 wt.% GNP and 0.5, 1.0, and 1.5 wt.% hBN nanoparticles. The dynamic viscosities of these seven settings showed higher viscosity for GNP-incorporated oils compared to that with hBN. The boundary lubrication regime was targeted for the coefficient of friction (COF) and wear analyses during each pin on the disk test. It was observed that for the GNP, 1.5 wt.% provided the minimum COF (52% less than base oil), whereas, for the hBN, 1.0 wt.% provided the lowest (40% less than base oil) values. Based on these insights, three nano lubricant mixtures were formulated by incorporating both GNP and hBN settings in different ratios. These mixtures provided an optimum positive synergy by reducing 56% friction and 90% wear compared to the base oil. These percentage values were significantly more compared to both GNP and hBN based lubricants in their individual settings. These improvements in the mixture were due to a composite film formed which protected the interacting surfaces and also due to the polishing mechanisms. Therefore, incorporating both these nanoparticles in canola oil could reduce friction and wear and thus help in better energy conservation.

Bioplastics have introduced numerous flexibilities to humankind. However, bioplastics have brought newer challenges in waste management. Approximately half of the current bioplastic market is not biodegradable, and with a larger market volume, its end-of-life allocation will be problematic for the governments and policymakers. This study aims to provide an overview of the non-biodegradable bioplastics market, including their underlined challenges, typical production methods, characterization, and possible alternative waste utilization perspective. Bioplastic production usually starts from a biological source i.e., biomass and a series of modification techniques such as pretreatment, hydrolysis, and fermentation are carried out to produce bioethanol. Then, bioethanol is converted to non-biodegradable bioplastics. The major non-biodegradable bioplastics are bio-polyethylene (bio-PE), bio-polypropylene (bio-PP), bio-polyethylene-terephthalate (bio-PET), bio-polytrimethylene terephthalate (Bio-PTT), and bio-polyamide (bio-PA). In this review article, an overview of each bioplastic is presented with flow diagrams. Also, the production method of compostable bioplastics—polylactic acid (PLA) — is briefly discussed for comparison purpose. Since the chemical structure of bio-based non-biodegradable plastics is similar to the conventional fossil-based plastics, the characterization and alternative thermochemical utilization techniques of five bioplastic wastes are discussed based on the conventional plastics characterizations. Per ultimate analysis, considering high hydrogen, low oxygen, and low fixed carbon content, bio-PE and bio-PP are recommended as potential feedstocks for the catalytic pyrolysis process to produce gasoline and diesel range liquid hydrocarbons. Alternatively, bio-PET, bio-PA, and PLA are recommended as potential feedstocks for the gasification process, considering their higher oxygen content.

Abstract: Biomass-based pyrolytic oil exhibits a lower calorific value and contains oxygenated compounds, which need to be minimized to upgrade the biofuel quality. In addition, approximately 50% of the world’s current bioplastics are composed of similar chemicals found in traditional plastics, which are not biodegradable. Because of the lack of a suitable environment, bioplastics and recyclable plastics breach their designated waste chain and accumulate in landfills. To prevent these plastics from littering the ocean, alternative solutions are necessary. The overall goal of this research is to study the effects of the co-pyrolysis ratio of pinewood to high-density polyethylene (HDPE) plastic in order to reduce the oxygenated compounds and to improve the quality of pyrolysis oil. In this research, a double-column staged reactor was fabricated whereby the pine biomass to HDPE plastic ratio was varied between 0/100, 25/75, 50/50, 75/25, and 100/0 at 450℃, 500℃, and 550℃. A Zeolitic-based ZSM-5 catalyst was used with the feedstock at a ratio of 1:1, which cracked the heavy molecules into gasoline-range liquid hydrocarbons with a higher calorific value. Virgin HDPE was used for the co-pyrolytic feedstock. In addition, virgin low-density polyethylene; virgin polylactic acid; and waste plastics such as HDPE grocery bags, polyethylene terephthalate water bottles, and compostable bioplastic bags were investigated for the comparison with virgin HDPE. Virgin HDPE produced 30.54% liquid pyrolysis oil with a calorific value of 40.38 MJ/Kg and a selectivity of above 90% toward gasoline-range aromatic hydrocarbons at 500℃. Comparatively, at 500℃, pinewood offered 26.27% liquid pyrolysis oil yield with a heating value of 30.13 MJ/Kg and a gasoline selectivity of 69.30%. The addition of HDPE in the co-pyrolytic feed increased the hydrogen/carbon effective (H/Ceff) ratio and the gasoline selectivity simultaneously. The gasoline selectivity was also increased from 68.87% to 76.31% for 100% pine sawdust when the experimental temperature was increased from 450℃ to 550℃ with an H/Ceff of 0.029. However, for HDPE of above 50% or an H/Ceff ratio above 0.989, gasoline selectivity was above 90% at 450℃ and 500℃. Mixed plastics also demonstrated a liquid yield of 17.35% and the calorific value was 42.68 MJ/Kg with a gasoline selectivity of above 90%. Moreover, pyrolysis oil from both virgin and waste HDPE has shown a significantly higher selectivity toward C9 hydrocarbons. Among C9 hydrocarbons, cumene is used in gasoline as an octane booster. The gas contains (C1–C5) range hydrocarbons and typically consists of alkanes and alkenes, which are important from the point of view of the high calorific value of gaseous fuel. Therefore, the catalytic co-pyrolysis of pine and plastics has shown significant potential for improving the bio-oil quality of gasoline-range hydrocarbon fuels, and, in particular, HDPE has increased the quantity and quality of pyrolysis oil simultaneously.

A large portion of the physically disabled community of the world is currently using wheel chair which is not universally accessible. In many countries, public transport system depends on high floor bus and a wheel chair user fails to access to that comfortably. This research aims to demolish that problem of inaccessibility through a modification of the high floor bus door. The basic methodology here, consists of movable door-step system (one vertically and other horizontally) which allows the lifting of a wheel chair into the bus. Two linear actuators and two rack and pinion mechanisms are involved in this system. In this research, through simulation analysis the feasibility of the lifting step is tested. Eventually, the cost is discussed for performing this type of modification in a public bus in Bangladesh. So, this work will help people to find an effective mean to make public buses accessible for disabled persons. 

Now-a-days every field is heading towards automation, whereas agricultural field is still an exception. Current scenario says many countries do not have enough farmer to cultivate lands and even in Bangladesh there are lots of families that are lacking an able member to toil during harvesting period. To overcome this problem, a robot farmer is the optimum solution. The objective of this research is to design a robot farmer which can work in the crop-fields for automatically cutting and placing crops aside with a pre-installed embedded system. It will reduce the necessity of man-operated machineries. The total design of this robot farmer consists of 7 motors, a distance measuring sensor, and an Arduino board. This research work will be helpful for the researchers who are interested to introduce automation in the agricultural sector and who want to perform any smooth cutting operation which requires holding of an object before cutting.