Three-dimensional printed polymeric lattice structures have recently gained interests in several engineering applications owing to their excellent properties such as low-density, energy absorption, strength-to-weight ratio, and damping performance. Three-dimensional (3D) lattice structure properties are governed by the topology of the microstructure and the base material that can be tailored to meet the application requirement. In this study, the effect of architected structural member geometry and base material on the viscoelastic response of 3D printed lattice structure has been investigated. The simple cubic lattice structures based on plate-, truss-, and shell-type structural members were used to describe the topology of the cellular solid. The proposed lattice structures were fabricated with two materials, i.e., PLA and ABS using the material extrusion (MEX) process. The quasi-static compression response of lattice structures was investigated, and mechanical properties were obtained. Then, the creep, relaxation and cyclic viscoelastic response of the lattice structure were characterized. Both material and topologies were observed to affect the mechanical properties and time-dependent behavior of lattice structure. Plate-based lattices were found to possess highest stiffness, while the highest viscoelastic behavior belongs to shell-based lattices. Among the studied lattice structures, we found that the plate-lattice is the best candidate to use as a creep-resistant LS and shell-based lattice is ideal for damping applications under quasi-static loading conditions. The proposed analysis approach is a step forward toward understanding the viscoelastic tolerance design of lattice structures.

Polyaniline (PANI), which is a member of the family of electrically conducting polymers, has been widely discussed as a potential membrane for wastewater treatment. Although a steady growth in PANI literature was observed, analyzing PANI literature quantitatively is still a novelty. The main aim of this study is to unearth the current research status, global trends, and evolution of PANI membranes literature and their use in water treatment applications over time. For this purpose, a scientometric study was performed consisting of bibliometric and bibliographic analysis. A total of 613 entities were extracted from Web of Science published during the last 50 years and were analyzed to map trends based on leading peer-reviewed journals, publication records, leading research disciplines, countries, and organizations. The study shows that the number of annual publications increased exponentially from 2005 to 2020 and is expected to keep increasing in the current decade. The Journal of Membrane Science published the highest number of articles and was identified as the most-cited journal in the field. China, India, and the USA were observed as the top three research hubs. The top-ranked authors in the field were Wang, Jixiao, and Wang, Zhi. To find research trends, four different clusters of keywords were generated and analyzed. The top five most frequent keywords turn out to be polyaniline, water, performance, membranes, and nanoparticles. The analysis suggests that the application of nanotechnology for modifying PANI membranes (using nanoparticles, nanotubes, and graphene specifically) is the future of this field. This study elucidates the research streamline of the field that may serve as a quick reference for early career researchers and industries exploring this field.

Shipbuilding industry is a valuable and profit earning industry which plays a vital role in country’s economic development. Ships have crucial impact on country’s trade due to necessary support for maritime transportation. Moreover, ships can be utilized for protecting coastal area. Steel chiefly utilized for ships construction due to its good strength and durability. This study emphasizes on residual stress analysis of AH-36 shipbuilding steel. Abaqus software is utilized for finite element analysis to evaluate residual stresses. Mitigation of these residual stresses is very essential; hence preheating technique is discussed in this study. Preheating was conducted at three temperatures i.e., 100ºC,150ºC and 200ºC. Results indicate that Von Mises stresses were decreased effectively due to preheating. 12.6%, 21% and 45.6% reduction were observed at preheating temperatures 100ºC, 150ºC and 200ºC respectively. Further evaluation of stresses revealed that due to preheating of base plate, longitudinal stresses reduced to 21.3%, 44% and 52.4% by increasing preheating temperature from 100ºC,150ºC and 200ºC, respectively. Mitigation of thermal gradient between weld zone and base plate resulted in reduction in overall stresses of base plate.

This study developed a methodology for determining the intercept factor (γ) and reports the effects of varying the design parameters, within realistic ranges, on the optical performance of parabolic trough collectors (PTC). The design equations account for the aperture width of the concentrator, the geometric concentration ratio, rim-angle and misalignment of the receiver, characterized by the radial and angular offsets. The Latin Hypercube Sampling (LHS) based ray-tracing method was used. Validation of the method was performed by comparing the results obtained by tracing a single ray with measurements obtained in a 2D drafting program. Then, parametric analyses were performed to determine the effects of changing the radial and angular offset, geometric concentration ratio and rim-angle on the percentage change in intercept factor (γ_Δ) with respect to the γ of a PTC with a perfectly aligned receiver. Finally, contour plots depicting the γ of various standard troughs over the range of radial and angular offsets were plotted, compared and discussed. An online tool is also presented to help designers and researchers analyze these effects quickly by providing the design parameters.

Date palm tree (DPT) and pine tree (PT) needles in forests form a combustible mat, posing fire risks during summer in Pakistan that damage vegetation, wildlife habitats, and biodiversity and impact local livelihoods. In this article, sintered ceramic specimens were prepared at different weight concentrations (DPT5, DPT10, DPT20, and DPT 30 and PT5, PT10, PT20, and PT30) of date palm tree leaf ash and pine tree needle ash as secondary additives in ceramic manufacturing along with primary material kaolinite (China clay). Raw materials composition was analyzed using X-ray diffraction (XRD), taking loss on ignition, water absorption, bulk density, saturated surface dry density (SSD), weight per unit area, and thermal cycling as measurement indexes. The result indicates that loss on ignition increases while increasing the quantity of secondary additives and the maximum increase for DPT30 was 19.6% and for PT30, it was 22.1%. As the secondary additives increase, the water absorption rate also increases and the maximum increase for DPT30 and PT30 is 4.5%. Meanwhile, with the increase in secondary additives, the density decreased; for DPT 30, it was 1457.7 kg/m³ and for PT30, it was 1829.8 kg/m³. Thermal performance was investigated by heating and cooling cycles. It was observed that thermal performances increase with the increase in secondary additives. The results reveal this novel approach has the potential to form a ceramic and good properties can be achieved. The prepared specimens have the potential to be used in the fields of electronics, aerospace, construction, and building engineering, alleviating environmental strain, curbing the exhaustion of China clay reserves, and most importantly, lowering the risk of forest fires in Pakistan.

This research focuses on the study of the simulation capabilities of the lagrangian (LAG) model and Smoothed Particle Hydrodynamics (SPH) model for the orthogonal dry machining of aluminum alloy Al6061-T6. A three-dimensional finite element model was developed and verified using experimental data from the published literature. The numerical models were developed using lagrangian boundary conditions via finite element modeling in ABAQUS/Explicit 6.14. The cutting simulations were carried out at low and medium cutting speeds. Johnson–Cook material constitutive law and Johnson–Cook damage law were used in both models. The numerical methodologies are compared based on cutting forces, chip morphology, shear angle, chip separation criterion, and chip thickness. The findings of the present work show that the LAG model is good for predictions regarding cutting forces and chip morphology, while the SPH model is good for predictions regarding the shear angle and chip thickness. The difference between results generated by both models mainly occurred due to the friction coefficient. The comparative study shown here offers a guidance approach for various numerical models for appropriate parameter analysis.