Scholarly Work - Mechanical & Industrial Engineering
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8878
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Item Hydromulches suppress weeds and maintain fruit production in organically managed strawberry systems(Frontiers Media SA, 2024-05) Ahmad, Waqas; DeVetter, Lisa W.; McFadden, Dakota; Maupin, Brian; Bajwa, Dilpreet S.; Durado, Andrew; Weyers, Sharon; Galinato, Suzette P.; Weiss, Ben; Gramig, GretaPolyethylene (PE) mulches are widely used in strawberry (Fragaria × ananassa Duch) production for weed suppression and crop growth optimization. However, PE mulches are not biodegradable and contribute to plastic pollution. Our objective was to develop and test biodegradable liquid-applied ‘hydromulches’ (HMs) as a sustainable alternative to PE mulch. HM weed suppression efficacy, strawberry plant growth, and yield were evaluated. HM formulations consisted of shredded newsprint paper (NP), water, and a tackifier, either guar gum (GG) or psyllium husk (PH) added at 2 or 6%. Experiments were conducted at two environmentally distinct locations: northwest Washington (WA) and eastern North Dakota (ND). Five HM formulations were compared to black PE mulch within a randomized complete block design with four replications. PE mulch suppressed weeds completely at peak weed emergence and peak weed vegetative growth at both locations. Formulations of HM containing GG provided superior weed suppression compared to other HM formulations at peak weed emergence (4–6 vs. 18–22 plants m-2, respectively). At peak vegetative growth, HM formulations containing GG had the lowest weed density compared to other HMs in ND (1 vs. 9–12 plants m-2), whereas these differences were not observed in WA. Total weed biomass did not differ among HMs across both locations. GG HM formulations deteriorated similarly to PE mulch (3–5% vs. 2%, respectively) in ND, whereas other HMs deteriorated more substantially. In WA, all HMs deteriorated more than PE mulch (6–12% vs. 1%, respectively). Fruit yield did not differ among treatments in weedy and weed-free subplots (194–254 g plant-1) in WA. In ND, yield was greater in all HM treatments compared to PE mulch in both weedy and weed-free subplots. Across both locations, strawberry canopy cover was greater in PE mulch (56.1% canopy cover) compared to 2%GG and NP (42.4 and 39.8% canopy cover). Strawberry plant biomass was similar among mulch treatments. However, strawberry leaf and crown biomass were slightly lower in 2%PH compared to other mulch treatments. Results demonstrate HMs with GG tackifier are a promising alternative to PE mulch in organic strawberry systems based on ability to suppress weeds, enhance strawberry growth, and maintain yield.Item Natural polymer hydrogel based 3D printed bioreactor testing platform for cancer cell culture(Elsevier, 2024-06) Rehovsky, Chad; Bajwa, Dilpreet S.; Mallik, Sanku; Pullman, Jessica E.; Ara, IsmatAlthough two-dimensional cell cultures provide a time- and cost-effective method for testing drugs at the preclinical level, they do not capture the three-dimensional cellular interactions or tumor penetration that must occur in vivo. Therefore, these drugs often fail as they transition from two-dimensional culture models to more complex ones, including animal models or even human clinical trials. The goal of this research was to develop a three-dimensional bioprinted pancreatic cancer drug testing platform that could increase the effectiveness of drug testing during the early preclinical stages. Specifically, different natural polymer hydrogel formulations of cellulose, alginate, and gelatin were tested to find the optimal printability and cell viability. It was determined that a cellulose nanocrystal and alginate hydrogel provided the best printability because of its superior shear thinning properties. In addition, BxPC-3 cells, that were printed and then cultured within this hydrogel for four days, exhibited a range of cell viability between 80 % and 60 %. To simulate vasculature around the bioprinted cultures, a spinning bioreactor was manufactured; however, it disturbed the cells, leading to a decrease in cell viability compared to stagnant cultures. Overall, the platform demonstrated good printability and cell viability for future use in pancreatic cancer drug testing.Item Nano Boron Oxide and Zinc Oxide Doped Lignin Containing Cellulose Nanocrystals Improve the Thermal, Mechanical and Flammability Properties of High-Density Poly(ethylene)(MDPI, 2023-12) Bajwa, Dilpreet S.; Holt, Greg; Stark, Nicole; Bajwa, Sreekala G.; Chanda, Saptaparni; Quadir, MohiuddinThe widely used high-density polyethylene (HDPE) polymer has inadequate mechanical and thermal properties for structural applications. To overcome this challenge, nano zinc oxide (ZnO) and nano boron oxide (B2O3) doped lignin-containing cellulose nanocrystals (L-CNC) were blended in the polymer matrix. The working hypothesis is that lignin will prevent CNC aggregation, and metal oxides will reduce the flammability of polymers by modifying their degradation pathways. This research prepared and incorporated safe, effective, and eco-friendly hybrid systems of nano ZnO/L-CNC and nano B2O3/L-CNC into the HDPE matrix to improve their physio-mechanical and fire-retardant properties. The composites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, thermo-gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, horizontal burning test, and microcalorimetry test. The results demonstrated a substantial increase in mechanical properties and a reduction in flammability. The scanning electron microscope (SEM) images showed some agglomeration and irregular distribution of the inorganic oxides.Item Design of Experiment to Determine the Effect of the Geometric Variables on Tensile Properties of Carbon Fiber Reinforced Polymer Composites(MDPI AG, 2023-05) Janicki, Joseph C.; Egloff, Matthew C.; Bajwa, Dilpreet S.; Amendola, Roberta; Ryan, Cecily A.; Cairns, Douglas S.Carbon fiber reinforced polymers (CFRPs) are increasingly used in the aerospace industry because of their robust mechanical properties and strength to weight ratio. A significant drawback of CFRPs is their resistance to formability when drawing continuous CFRPs into complex shapes as it tends to bridge, resulting in various defects in the final product. However, CFRP made from Stretch Broken Carbon Fiber (SBCF) aims to solve this issue by demonstrating superior formability compared to conventional continuous CFRPs. To study and validate the performance of SBCF, a statistical design of the experiment was conducted using three different types of CFRPs in tow/tape form. Hexcel (Stamford, CT, USA) IM7-G continuous carbon fiber impregnated with Huntsman (The Woodlands, TX, USA) RDM 2019-053 resin system, Hexcel SBCF impregnated with RDM2019-053 resin, and Montana State University manufactured SBCF impregnated with Huntsman RDM 2019-053 resin were tested in a multitude of forming trials and the data were analyzed using a statistical model to evaluate the forming behavior of each fiber type. The results show that for continuous fiber CFRP tows forming, Fmax and Δmax do not show statistical significance based on temperature fluctuations; however, in SBCF CFRP tows forming, Fmax and Δmax is dominated by the temperature and geometry has a low statistical influence on the Fmax. The lower dependence on tool geometry at higher temperatures indicates possibly superior formability of MSU SBCF. Overall findings from this research help define practical testing methods to compare different CFRPs and provide a repeatable approach to creating a statistical model for measuring results from the formability trials.Item Hydraulic bulge testing to compare formability of continuous and stretch broken carbon fiber reinforced polymer composites(Springer Science and Business Media LLC, 2023-02) Shchemelinin, Yoni; Nelson, Jared W.; Ryan, Cecily; Bajwa, Dilpreet S.; Cairns, Doug; Amendola, RobertaThe use of carbon fiber reinforced polymer composites has increased with the increased need for high-strength, low-density materials, particularly in the aerospace industry. Stretch broken carbon fiber (SBCF) is a form of carbon fiber created by statistically distributed breakage of aligned fibers in a tow at inherent flaw points, resulting in a material constituted of collimated short fibers with an average length larger than chopped fibers. While continuous carbon fiber composites have desirable material properties, the limited ability to form in complex geometries prevents their wide adoption. SBCF composites exhibit pseudo-plastic deformation that can potentially enable the use of traditional metal forming techniques like stamping and press forming, widely used for mass production applications. To investigate the formability of carbon fiber reinforced polymer composites prepared with either continuous or stretch broken Hexcel IM-7 12 K fibers and impregnated with Huntsman RDM 2019–053 resin, hydraulic bulge testing was performed at atmospheric pressure and elevated temperature to explore the strain behavior under biaxial stress conditions for the material system. Results based on deformation of surface patterning, bulge apex displacement and measurement of the bulge internal surface and volume, support the enhanced formability of the SBCF material when compared to its continuous counterpart. The SBCF enhanced formability is characterized by an axisymmetric stress response and a failure mechanism similar to the one observed for sheet metalItem Formability Characterization of Fiber Reinforced Polymer Composites Using a Novel Test Method(ASTM International, 2021-10) Janicki, Joseph C.; Egloff, Matthew C.; Amendola, Roberta; Ryan, Cecily A.; Bajwa, Dilpreet S.; Dilpreet S., Alexey; Cairns, Douglas S.Fiber reinforced polymer composites are often used as a replacement for metal alloys because of the superior strength to weight ratio. However, a major drawback of these materials is the lack of formability caused by the low strain to failure ratio that does not allow the material to follow tooling contours into deep drawn shapes or tight radii. Composite materials have a multiscale hierarchical structure where micro and meso scale effects (fiber and tow scales) contribute to the macro structural response (laminate scale). In particular, during forming, different deformation occurs simultaneously at every scale. Currently, the amount of quantifiable and comparable forming data for both continuous and discontinuous fiber reinforced polymer composites, including a multi-scale understanding of the deformation response, is limited because of the lack of a testing system. This article proposes a novel test method and an apparatus called “the forming fixture” for testing the tow formability of fiber reinforced polymer composites by determining the required load to form an uncured resin impregnated fiber tow sample into a stretch drawn profile. Test results from forming of Hexcel (Stamford, CT) IM7-G continuous carbon fiber impregnated with Huntsman (The Woodlands, TX) RDM 2019-053 resin system, in the temperature range of 21°C–121°C, are discussed to demonstrate the use of the proposed apparatus including representative data. Results showed consistency and repeatability, validating the reliability of the novel method. The test aided in defining the forming behavior of the material in real time both visually (e.g. sample failure location) and as forming load versus displacement curves. A novel forming metrics, relating the maximum drawing depth with no failure and the maximum forming load, is defined to compare and select different fiber and resin formulations. Widespread adoption of the forming fixture will reduce reliance on a “trial and error” approach during the the forming process.Item Silane compatibilzation to improve the dispersion, thermal and mechancial properties of cellulose nanocrystals in poly (ethylene oxide)(Informa UK Limited, 2021-01) Chanda, Saptaparni; Bajwa, Dilpreet S.; Holt, Greg A.; Stark, Nicole; Bajwa, Sreekala G.; Quadir, MohiuddinCellulose nanocrystal (CNC) has potential to be used as a reinforcement in polymeric nanocomposites because of their inherent biodegradability, universal accessibility, and superior mechanical properties. The most crucial challenge faced in the nanocomposite production is dispersing the nanoparticles effectively in the polymer matrix, so that the exceptional mechanical properties of the nanoparticles can be transferred to the macroscale properties to the bulk nanocomposites. In this research, a safe, effective and ecofriendly modification was used to functionalize the surface hydroxyl groups of CNC via silane treatment. These modified CNCs were used as reinforcements to prepare poly (ethylene oxide) (PEO)/CNC nanocomposites. The composites were prepared using solvent casting method. The composite properties were evaluated using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Dynamic Mechanical Analysis (DMA). The SEM micrographs demonstrated that the composites incorporated with silane treated CNCs showed improvement in the dispersion behavior of the nanoparticles in the matrix. Oxidative combustion of the composites containing silane treated CNCs promoted char formation and enhanced thermal stability. The composites containing (1:1) silane treated CNCs exhibited the better crystallization ability, highest storage modulus, and lowest tan δ value compared to the other silane treated systems indicating improved dispersion of CNC. The polysiloxane network provided an efficient surface covering of the CNC molecules, imparting reduced polar surface characteristics and enhancing the overall mechanical properties of the composites.Item Role of Hybrid Nano-Zinc Oxide and Cellulose Nanocrystals on the Mechanical, Thermal, and Flammability Properties of Poly (Lactic Acid) Polymer(MDPI AG, 2021-02) Bajwa, Dilpreet S.; Shojaeiarani, Jamileh; Liaw, Joshua D.; Bajwa, Sreekala G.Biopolymers with universal accessibility and inherent biodegradability can offer an appealing sustainable platform to supersede petroleum-based polymers. In this research, a hybrid system derived from cellulose nanocrystals (CNCs) and zinc oxide (ZnO) nanoparticles was added into poly (lactic acid) (PLA) to improve its mechanical, thermal, and flame resistance properties. The ZnO-overlaid CNCs were prepared via the solvent casting method and added to PLA through the melt-blending extrusion process. The composite properties were evaluated using SEM, a dynamic mechanical analyzer (DMA), FTIR TGA, and horizontal burning tests. The results demonstrated that the incorporation of 1.5% nano-CNC-overlaid ZnO nanoparticles into PLA enhanced the mechanical and thermal characteristics and the flame resistance of the PLA matrix. Oxidative combustion of CNC-ZnO promoted char formation and flame reduction. The shielding effect from the ZnO-CNC blend served as an insulator and resulted in noncontinuous burning, which increased the fire retardancy of nanocomposites. By contrast, the addition of ZnO into PLA accelerated the polymer degradation at higher temperature and shifted the maximum degradation to lower temperature in comparison with pure PLA. For PLA composites reinforced by ZnO, the storage modulus decreased with ZnO content possibly due to the scissoring effect of ZnO in the PLA matrix, which resulted in lower molecular weight.Item Cellulose nanocrystal based composites: A review(2021-07) Shojaeiarani, Jamileh; Bajwa, Dilpreet S.; Chanda, SaptaparniCellulose nanocrystals (CNC) have received much attention as renewable, biodegradable, nontoxic, and low-cost nanomaterials with some remarkable properties. Desirable engineering properties of CNC include large surface to volume ratio, high tensile strength (~10 GPa), high stiffness (~110–130 GPa), and high flexibility. They can be chemically modified to tailor their properties for high-end engineering and biomedical applications. Despite their outstanding properties, the wide-scale application is lacking due to their surface characteristics and processing challenges. To achieve their full potential safer extraction methods, improved surface modification and functionalization methods and processing techniques are being researched. This review attempts to access methods for characterizing CNC, and CNC composites as well as their emerging new applications as smart materials. The review is a valuable resource for researchers and scientists working in industry or academia to provide an update on the use of CNC materials and their composites in packaging, biomedical, and high-efficiency energy systems.