Mass Change Measurements Research Articles

Investigating the Effects of Electrolytes on Li Deposition By Electrochemical Quartz Crystal Microbalance

Batteries for EVs and grid-scale energy storage are necessary to meet the increasing energy demands in modern society and support the creation of a net-zero emission world. Among various kinds of batteries, lithium metal batteries (LMBs) using lithium metal anodes (LMAs) are one of the most promising candidates. They provide high theoretical specific capacity (3,860 mAh g-1) and high specific energy (>500 Wh kg-1), improving performance beyond what is possible with lithium-ion batteries1,2. However, the high reactivity of LMAs brings problems like low Coulombic efficiency and poor cycling stability to the LMBs. Electrolyte engineering is one approach to solve these problems since it can enable smooth, compact, and uniform Li deposition with large particles. Considering the strong size effect on mechanical properties of Li, desired Li deposits exhibit different mechanical properties, such as shear modulus, compared with smaller Li particles3. Therefore, studying mechanical properties of Li at micrometer scale is also important for forming desired Li deposition and can guide the design of next-generation electrolytes. To investigate the mechanical properties of favored Li deposits, an in situ characterization technology of electrochemical quartz crystal microbalance (EQCM) is employed.In this presentation, we will discuss the mechanisms of Li deposition in LMBs studied by EQCM. This technique allows the in situ monitoring of mass changes, as well as the measurements of mechanical properties detected by EQCM-dissipation (EQCM-D) mode4. We used it to investigate the Li film formed by different electrolytes, especially focusing on localized high concentration electrolytes (LHCEs), which are the state-of-the-art electrolytes in LMBs5. The effects of different diluents including 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE), tris(2,2,2-trifluoroethyl)orthoformate (TFEO), and bis(2,2,2-trifluoroethyl) ether (BTFE) were studied. The measurements of mass change and modulus of Li film can give new insights into the mechanisms of Li deposition, supporting the other characterization techniques such as SEM. Ultimately, this study provides new insights into the subtle mechanical differences of Li metal deposited in different electrolytes. This will guide the next-generation electrolyte design for achieving high Coulombic efficiency, excellent cycling stability, and practical application for LMBs.

From Mechanism Study to Catalyst Design: Exsolved Ru Nanocatalysts on Proton Conducitng Oxide for Efficient Ammonia Synthesis

Since it was revealed that the ammonia synthesis reaction is associated with the nitrogen adsorption energy, represented by a volcano plot, the catalysts placed near the peak of volcano plot, particularly ruthenium (Ru), have been actively investigated. For high efficiency of ammonia synthesis under mild conditions, the requirements of supported Ru catalysts are i) electron donating ability of supports (as promoters) that weakens the N≡N bond, ii) hydrogen absorption/desorption capability of supports to suppress H2 poisoning on Ru surface, iii) refractory property for maintaining high specific surface area of supports, and iv) the structurally robust and uniformly distributed Ru nanoparticles. However, the supported Ru catalyst that simultaneously fulfills all requirements above has yet been developed. Here we report a highly active exsolved Ru nanocatalyst supported on perovskite proton conducting oxide, BaCe0.55Zr0.3Y0.15O3-δ (BCZY), for ammonia synthesis at atmospheric pressure based on the understanding of exsolution mechanism.The supported catalyst, 5mol% Ru-added BCZY, BaCe0.5Zr0.3Y0.15Ru0.05O3-δ, was synthesized via solid state reaction using appropriate amount of oxide precursors. Analyses of XRD for crystal structure, TEM for microstructure observation, TGA for measurement of mass change against temperature, XPS for determination of oxidation state, BET for surface area measurement, and catalytic activity for quantifying ammonia synthesis rate were carried out.The exsolution is basically driven by reduction of oxide support, corresponding to the mass loss owing to the oxygen release. Thus, the decrease in mass directly associated with the Ru exsolution in a form of metal. Based on in situ TG profile at 1000oC under reducing atmosphere, it was verified that the Ru exsolution process is controlled by size-related strain, and the degree of exsolution can be effectively enhanced as the reduction time increases, e.g., from 1h to 20h. The exsolved Ru nanoparticles on proton-conducting oxide support formed by 20h reduction treatment at 1000oC had diameter of ~6 nm, and exhibited higher catalytic activity for ammonia synthesis reaction compared to exsolved Ru via 1h reduction treatment as well as the previously reported catalysts. The use of proton conducting oxide support, which has electron donating capability, structurally refractory property, and hydrogen absorption/desoprtion capability, could possibly be synergistic to boost the catalytic activity of exsolved Ru nanocatalyst. In this presentation, the details on exsolved Ru catalyst as a function of temperature, probable exsolution mechanism, and role of proton conducting oxide support will be further discussed.

Dynamic Impedance Model of Low-Voltage Electric Shock in Animals Considering the Influence of Water Electrolysis

This study aims to tackle the challenge of explaining the underlying mechanisms behind the time-varying impedance phenomenon in animals experiencing low-voltage electric shocks. A dynamic impedance model that considers the effect of water electrolysis (WEDI) has been developed. First, we conducted root cause analyses through progressive validation experiments, identifying water within the shocked body as the key factor influencing impedance variation. Monitoring hydrogen concentration above the electrodes and measuring mass changes in the shocked body revealed that the time-varying impedance is closely related to internal water electrolysis. Second, we quantitatively analyzed the impact of water molecule decomposition during electrolysis on the salt concentration and conductivity within the electrically shocked body. A mathematical relationship between the variable resistance within the body and time was derived. A dynamic impedance model for animal electric shock that considered the effects of water electrolysis was subsequently established, explaining the underlying mechanism behind the time-varying impedance phenomenon. Finally, the Mean Absolute Percentage Error (MAPE), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE) between the electric shock current predicted by the WEDI model and actual measurements were 0.00357, 0.00350, and 0.00446. Compared to existing models, the WEDI model demonstrates superior accuracy and interpretability.

Non-Isothermal Thermogravimetric Analysis of Carbonation Reaction for Enhanced CO2 Capture

An in-depth investigation into CaO-based carbonation reaction kinetics for CO2 sorption is being conducted using simultaneous thermal analysis (STA), with the application of advanced thermogravimetric and differential scanning calorimetry techniques. Utilizing advanced thermal analysis system for real-time monitoring of simultaneous measurements of mass changes and thermal effects are conducted, ensuring precision and versatility in data acquisition. The study explores the intricacies of the non-isothermal carbonation process across a wide range of temperatures, shedding light on the temperature-dependent trends in reaction rates. Innovative statistical methods, combining regression techniques and Arrhenius equation, are employed to determine energy and reaction kinetics. The sensitivity of carbonation process to varying pressure conditions is meticulously examined in the study, providing pivotal discernment for optimization of reaction parameters across diverse applications. The integration of STA with statistical modeling alongside systematic analysis of temperature-dependent trends and pressure-order relationships not only enhances the understanding of CO2 capture efficiency but also improves the robustness and accuracy of the findings. Furthermore, meticulous cross-validation with existing studies provides a critical evaluation of the experimental approach’s precision and limitations. This study enhances understanding of CaO carbonation kinetics, providing practical implications for carbon capture processes and contributing to sustainable industrial processes.

QCM Biosensors for pathogen detection in water and food: review of published literature

Introduction:This article is the result of the review “QCM Biosensors for the Detection of Pathogens in Water and Food: A Review,’ conducted during the years 2023 and 2024 at the Universidad Distrital Francisco José de Caldas”Problem: The fast evolution of pathogen detection through biosensors requires a continuous synthesis of literatu-re to provide an integral comprehension of the state of the art to new researchers. Objective:Perform bibliography research about QCM Biosensors used for pathogen detection in food and water covering a period from 2018 to 2023.Methodology: The research includes three phases: An explanation of the principles of QCM biosensors, their use in water and food pathogen detection, and their use in industry, with an emphasis on water quality.Result:QCM biosensors are solid, measure mass changes at the micro and nanometric scales, and are widely used in the food industry due to their accuracy and ease of use.Conclusion: The review highlights the effectiveness of QCM biosensors when detecting different food contami-nants and pathogens. It underlines the practical research necessity and importance of updating review papers to orientate future investigations in this specific area.Originality:The originality of this review lies on its detailed approach to QCM biosensor use in food pathogen detection.Limitations:The constant evolution of the field of pathogen detection in addition to the diversity of QCM biosen-sors and the wide range of pathogens studied may make it difficult to generalize certain findings.

Abstract 5177: Ex vivo assessment of cellular mass response predicts clinical efficacy in solid tumors

Abstract Introduction: Identifying personalized, efficacious therapies for cancer remains an urgent unmet need in oncology. While genomics-based biomarkers have demonstrated significant progress, they are not universally applicable, with most patients still treated using clinical guidelines. Experimental procedures: We have previously demonstrated broad clinical applicability of a functional precision medicine (FPM) workflow that incorporates high-resolution measurements of single-cell mass changes in response to drugs. As a highly integrative biomarker of cellular state, mass change serves as a rapid and mechanism agnostic readout of drug response, demonstrating an ability to detect signal from over 100 different cytotoxic and targeted therapies within 24 hours of treatment ex vivo. As a single-cell assay that requires as few as 10,000 cells to assess drug response, this method does not require any ex vivo culture for cell expansion and is compatible with a range of clinically relevant tissue specimen formats. Together, these features have enabled this mass response framework to be implemented in a CLIA-certified laboratory with a reporting turnaround time of just two days. Summary of the new, unpublished data: Having previously shown that mass response testing is compatible with various solid tumor specimen formats such as malignant fluids, core biopsies and fine needle aspirates, here we present preliminary results that demonstrate compatibility with surgically resected tissue specimens. Specifically, we demonstrate that mass response testing results correlate with clinical response across of broad array of solid tumors. In our cohort of 24 patients, we found that mass response measurements correlated with clinical response to therapy with an accuracy of 83% (OR=19.66, P=0.003). Within this group, we also found clear examples of how mass response testing can serve as a valuable complement to existing genomic approaches to guide therapy. Importantly, we demonstrate both concordant and discrepant results using small molecule inhibitors in the setting of known biomarkers of response, highlighting the need for functional testing in precision cancer medicine. Conclusions: These results support that mass response testing is feasible and broadly applicable to solid tumor malignancies and may serve as a valuable complementary readout for informing therapeutic selection for cancer patients. Citation Format: Robert Kimmerling, Mark Stevens, Selim Olcum, Madeleine Vacha, Rachel LaBella, Katie Katsis, Reginald Aikens, Cathleen Hannah, Audrey Guo, Juanita Fujii, Zayna Shaheen, Srividya Sundaresan, Ashley Rainey, Andrew M. Blakely, Jonathan Hernandez, Anobel Tamrazi, Clifford Reid. Ex vivo assessment of cellular mass response predicts clinical efficacy in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5177.

Chemical expansion of La3+ and Yb3+ incorporated Zr-doped ceria ceramics for concentrated solar energy-driven thermochemical production of fuels

Redox studies on Zr, La, Yb doped ceria (Ce0.9M3+/4+0.1O2-x, M3+/4+ = Zr4+, La3+, Yb3+ and CeZr0.05 M3+0.05O1.95, M3+ = La3+, Yb3+) ceramics were performed using dilatometry and mass change measurements to analyze the chemical and thermal volume changes depending on reduction state which can have dramatic effects on the long-term stability of these ceramics in Concentrated Solar Energy (CSE)–driven applications relevant to the synthesis of fuels. The reduction extents determined by both methods under vacuum (p = 2×10−5 mbar) are similar up to 1673 K. At higher temperatures, CeO2, which has a higher vapor pressure than the oxides of the dopant ions, evaporates. As a result, there is an accumulation of doping ions, which leads to a porous surface zone. Surface enrichment of dopants, especially that of Zr4+, is crucial for re-oxidation kinetics. Co-doping with trivalent doping ions such as La3+ and Yb3+ reduces the extent of selective evaporation materializing it into a thinner porous surface layer. Trivalent dopants and their additional oxygen vacancies also influence the chemical expansion/contraction of the Zr4+ doped ceria crystal lattice during the redox reaction and thus lead to a reduction of mechanical stresses. We assume that additional oxygen vacancies from trivalent dopant ions promote the disordering of intrinsic oxygen vacancies, while smaller tetravalent ions such as Zr4+ compensates this effect. This explains that doped ceria with trivalent and tetravalent ions show almost the same chemical expansion as pure ceria. The new results on alteration, thermal and chemical expansions/contractions at high temperature are particularly important for the development of metal oxide ceramic components exposed to cyclic reducing and oxidizing atmospheres at elevated temperatures achieved via CSE.

Measurement of water vapor transmission properties using the cup method – error caused by air buoyancy

The determination of water vapor transmission properties is commonly performed using the cup method. The method is based on periodic weighing of the cup assembly over time. If the air density surrounding the balance differs between weighings, measured change of mass is affected by the difference of ambient air buoyant force. For the correction of this effect can be used a mathematical formula presented in the literature and standards. The ASTM E96 states that this correction is important if observing changes of water vapor mass 0–100 mg. This paper therefore analyses possible errors of measured water vapor transmission properties based on a single 100 mg mass change without applying the buoyancy correction. It was found that for most common samples of building materials (sd < 3 m) and regular sizes of cup assemblies the error of a single mass change measurement can be up to ca. ±13 %, while assemblies with higher volume, higher mass, or more vapor tight samples can experience an error up to ±26 %. However, the vapor transmission properties are usually determined based on five consecutive weight changes. In that case the error can be up to five times lower (±2.5–5 %). Regarding the formula of the buoyancy correction the most important parameter was found to be the chosen volume of the cup assembly which, however, depends on particular setup and sample air-permeance. Only two extreme scenarios regarding this topic were analyzed while the full understanding of the accurate correction is still unsolved in its complexity.

Acoustic levitation of pollen and visualisation of hygroscopic behaviour

Abstract. Pollen are hygroscopic; therefore, they have the potential to act as cloud condensation nuclei (CCN) in the atmosphere. This could have uncertain implications for cloud processes and climate as well as plant biodiversity and human health. Previous studies have investigated the hygroscopic swelling of pollen, linked to CCN activity by the κ-Köhler theory, using methods that follow observed mass increase by electrodynamic balance (EDB) or vapour sorption analyser. This study uses an acoustic levitator to levitate pollen grains in the true aerosol phase and uses a macroscope to image the pollen to investigate hygroscopic behaviour when relative humidity (RH) is changed. Two pollen species were studied in this work: Lilium orientalis (oriental lily) and Populus deltoides (eastern cottonwood). Both species were successfully levitated; however, the smaller Populus deltoides showed greater instability throughout experiments. The quality of images taken by the macroscope, and thus calculations of pollen area and aspect ratio, varied significantly and were sensitive to lighting conditions as well as to levitated pollen grain movement and orientation. Experiments with surface-fixed pollen grains were also conducted. They showed evidence that pollen hygroscopic swelling could be observed by the macroscope. The produced results were comparable with previously reported mass increase values. Although less accurate than methods that measure mass changes, the acoustic levitator and macroscope set-up offer an attractive alternative by virtue of being commercial, off-the-shelf, low-cost, and versatile techniques. A key advantage of this method is that it is possible to visually observe particle shape dynamics under varying environmental conditions.

Quantifying the impact of X-band InSAR penetration bias on elevation change and mass balance estimation

AbstractInterferometric synthetic aperture radar (InSAR) data suffer from an elevation bias due to signal penetration into the firn and ice surface, rendering the height information unusable for elevation and mass-change detection. This study estimates the penetration bias in X-band InSAR data to quantify its impact on elevation and mass-change detection and to demonstrate the applicability of TanDEM-X digital elevation models (DEMs) for cryosphere research. To achieve this, a multiple linear regression model is applied to a time series of four TanDEM-X DEMs acquired between 2010 and 2018 over the Sverdrup Glacier basin (SGB), Devon Ice Cap, Canada. The resulting penetration corrected TanDEM-X DEMs agreed to within ±14 cm of spatially and temporally coincident precise in situ kinematic dGPS data (±10 cm RMSE). Additionally, multi-year estimations of mass change for the SGB derived from differencing TanDEM-X DEMs over multi-year periods between 2010 and 2018, showed good agreement with mean deviation of 338 ± 166 mm w.e. with independent measurements of mass change derived from annual in situ surface mass balance over the same time periods. The results show that the penetration bias can vary significantly, leading to random under- and overestimations in the detection of elevation and mass changes.

Design of a mechanism for applying sensitive films to gas sensors based on quartz crystal resonators

Gas sensors based on quartz crystal microbalance (QCM) are used to measure mass changes through frequency shifts, using the piezoelectric principle. These sensors are employed in odor detection and are essential for the development of electronic noses. For optimal performance, a sensitive film is applied to the surface of the crystal electrode, which is compatible with a specific compound. There are different methods of film deposition: ultrasonic atomization, spray coating, and casting. The casting method, which involves the manual application of sensitive films using a micropipette, is the most commonly used. However, it is not reproducible. To improve the casting method, a mechanism is proposed as a preliminary platform for a sensitive film application system. The objective is to achieve reproducibility in the construction of gas sensors by applying ethyl cellulose sensitive films onto the sensor surface, thereby reducing the margin of error. Tests were performed on the mechanism to verify the capabilities of the system for the deposition of sensing films using joysticks based on the resistance change principle.

CHARACTERIZATION OF A NOVEL ANTIMICROBIAL SOL-GEL DEVICE COATING TO PREVENT PERIPROSTHETIC JOINT INFECTION

An increasing elderly population means joint replacement surgery numbers are projected to increase, with associated complications such as periprosthetic joint infections (PJI) also rising. PJI are particularly challenging due to antimicrobial resistant biofilm development on implant surfaces and surrounding tissues, with treatment typically involving invasive surgeries and systemic antibiotic delivery. Consequently, functionalisation of implant surfaces to prevent biofilm formation is a major research focus. This study characterises clinically relevant antimicrobials including gentamicin, clindamycin, daptomycin, vancomycin and caspofungin within a silica-based, biodegradable sol-gel coating for prosthetic devices.Antimicrobial activity of the coatings against clinically relevant microorganisms was assessed via disc diffusion assays, broth microdilution culture methods and the MBEC assay used to determine anti-biofilm activity. Human and bovine cells were cultured in presence of antimicrobial sol-gel to determine cytotoxicity using Alamar blue and antibiotic release was measured by LC-MS. Biodegradability in physiological conditions was assayed by FT-IR, ICP-MS and measuring mass change. Effect of degradation products on osteogenesis were studied by culturing mesenchymal stem cells in the presence of media in which sol-gel samples had been immersed.Antimicrobial-loaded coatings showed strong activity against a wide range of clinically relevant bacterial and fungal pathogens with no loss of activity from antibiotic alone. The sol-gel coating demonstrated controlled release of antimicrobials and initial sol-gel coatings showed no loss of viability on MSCs with gentamicin containing coatings. Current work is underway investigating cytotoxicity of sol-gel compositions against MG-63 cells and primary osteoblasts.This research forms part of an extended study into a promising antimicrobial delivery strategy to prevent PJI. The implant coating has potential to advance PJI infection prevention, reducing future burden upon healthcare costs and patient wellbeing.

Global Mean Sea Level Rise Inferred From Ocean Salinity and Temperature Changes

AbstractBarystatic sea level rise (SLR) caused by the addition of freshwater to the ocean from melting ice can in principle be recorded by a reduction in seawater salinity, but detection of this signal has been hindered by sparse data coverage and the small trends compared to natural variability. Here, we develop an autoregressive machine learning method to estimate salinity changes in the global ocean from 2001 to 2019 that reduces uncertainties in ocean freshening trends by a factor of four compared to previous estimates. We find that the ocean mass rose by 13,000 ± 3,000 Gt from 2001 to 2019, implying a barystatic SLR of 2.0 ± 0.5 mm/yr. Combined with SLR of 1.3 ± 0.1 mm/yr due to ocean thermal expansion, these results suggest that global mean sea level rose by 3.4 ± 0.6 mm/yr from 2001 to 2019. These results provide an important validation of remote‐sensing measurements of ocean mass changes, global SLR, and global ice budgets.

A Monitoring System for Carbon Dioxide in Honeybee Hives: An Indicator of Colony Health

Non-dispersive infra-red (NDIR) detectors have become the dominant method for measuring atmospheric CO2, which is thought to be an important gas for honeybee colony health. In this work we describe a microcontroller-based system used to collect data from Senserion SCD41 NDIR sensors placed in the crown boards and queen excluders of honeybee colonies. The same sensors also provide relative humidity and temperature data. Several months of data have been recorded from four different hives. The mass change measurements, from hive scales, when foragers leave the hive were compared with the data from the gas sensors. Our data suggest that it is possible to estimate the colony size from the change in measured CO2, however no such link with the humidity is observed. Data are presented showing the CO2 decreasing over many weeks as a colony dies.

In-situ, real-time investigation of the formation of oxygen-containing rare-earth hydrides by combining a quartz crystal microbalance and ion beam analysis

We present an in-situ and real-time investigation of the formation of YHO and GdHO thin films grown by reactive e−-beam evaporation. Mass changes were continuously monitored during deposition, oxidation, and illumination using a highly sensitive quartz crystal microbalance, while changes in chemical composition and depth profiles were investigated simultaneously by ion beam analysis. Results highlight the strong reactivity of freshly deposited YHx and GdHx films, even under ultra-high vacuum conditions. Oxidation starts at the surfaces of the films and the oxidation rate is strongly dependent on the O2 pressure. The response of the system under ion beam irradiation and in-situ illumination is also presented and discussed. For the measured mass changes, a quantitative agreement better than 2% was observed between both techniques and demonstrates the consistency and sensitivity of this approach.

The Isothermal Oxidation of a New Polycrystalline Turbine Disk Ni-Based Superalloy at 800 °C and Its Modification with Pre-oxidation

Ni-based superalloys with enhanced oxidation resistance at high temperatures are crucial for next-generation gas turbine engines. A new polycrystalline Ni-based superalloy (C19) that combines improved microstructural stability with environmental resistance has been developed. Its oxidation resistance has been determined through measurements of the specific mass change and morphological evolution of the formed oxides following furnace exposures at 800 °C in air for up to 1000 hours; the results of which were benchmarked against Nimonic 105. C19 showed hybrid Type II/Type III behavior as a marginal Al2O3 former and performed similarly to established superalloys at 750 °C. The Wagner model for the transition from internal to external oxide formation predicted that C19 should form a continuous Al2O3 scale at higher temperatures. A pre-oxidation treatment at 1100 °C for 1 hour was, therefore, selected and shown to dramatically improve the oxidation resistance during subsequent exposure at 800 °C. Oxide cross-sectional analysis showed that C19 formed a continuous and protective Al2O3 scale after the pre-oxidation treatment, whereas Nimonic 105 retained discontinuous Al2O3 finger-like intrusions beneath a Cr2O3 overscale.

Corrosion Analysis of Al-Ce-X Cast Alloys in Dilute Boric Acid and 3.5 Wt.% NaCl Solutions

New compositions of Al-Ce-X cast alloys have been developed to offer higher material performances than the conventional Al alloys for nuclear and other industrial applications. To assess the corrosion behavior of these new Al-Ce-X alloys, mass change measurements and electrochemical analysis were conducted using 0.23 wt.% boric acid solution, relevant to the water chemistry for the storage pool of spent nuclear fuels, and a 3.5 wt.% NaCl solution approximating sea water. Pre- and Post-corrosion Al alloy specimens were characterized by electron microscope systems including SEM, TEM and EDS. The initial electrochemical and mass change results suggest that Al-Ce-X alloys are resistant to corrosion in 0.23 wt.% boric acid but can be susceptible to corrosion in 3.5 wt.% NaCl solution. The initial characterization of post-corrosion samples indicated that one Al-Ce-X alloy type experiences uniform corrosion without any preferential or local attacks. Further corrosion analysis and characterization are underway for comprehensive understanding of corrosion phenomenon in these new alloys.

Effects of surface treatments on ABS mechanical properties from fused filament fabrication

This paper examines the influence of surface treatments on the mechanical properties of acrylonitrile butadiene styrene (ABS) samples printed by fused filament fabrication (FFF). Prior efforts have applied brushing, painting, solvent dipping, infiltration, and vapor smoothing as post-processing surface treatments to improve the mechanical properties of FFF components. Additionally, because FFF can produce components with undesirable surface roughness, mechanical abrasion, epoxy coating, and acetone treatment may increase tensile strength by decreasing stress concentrations. Ridged surface texture may provide desirable tribological or handling properties. Based on these opportunities, this paper investigates abrasive media blasting, epoxy coating, acetone immersion, and ridged texturing surface treatments on the tensile strength and other mechanical properties of FFF ABS samples. ASTM D638-14 Type-I samples were printed, treated on all sample sides, and tested. From tensile tests, the elastic modulus, tensile strength, and fracture strain for both the untreated and treated ABS samples were calculated. For each sample, the surface finish and fracture macromorphology were observed with optical microscopy and the roughness values for the surface finish were calculated from profilometer data. Furthermore, samples were submerged in water and weighed periodically to measure mass changes due to water absorption. From surface profilometry and optical miscopy data, mechanical media blasting, epoxy coating, and immersion in all concentrations of acetone decreased surface roughness. Overall, on average, grit blasting with large beads and epoxy coating led to 2.6% and 1.2% increases in tensile strength, respectively; immersion in 40% acetone led to a 1.9% increase in tensile strength while treatment in 60% and 80% acetone decreased tensile strength by 4.9% and 1.9%, respectively. The study concludes that only grit blasting with large beads, immersion in 60% acetone, and the ridged texture significantly affected the tensile strength.

Saussurea obvallatta leaves extract as a potential eco-friendly corrosion inhibitor for mild steel in 1 M HCl

The extract of saussurea obvallatta leaves (SOLE) has been examined for corrosion inhibition studies for mild steel (MS) in 1 M HCl solution by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and traditional mass change measurements. SOLE controlled maximum of 90 % corrosion rate of MS in 1 M HCl solution at 200 ppm of SOLE. SEM-EDX, AFM and Contact angle images revealed that, MS surface was least affected by the acid solution in presence of SOLE. FT-IR and UV–Visible absorption spectral values established the set of a corrosion defensive layer over the MS surface. Potentiodynamic measurement revealed that SOLE act as a both anodic and cathodic type of inhibitor. Quantum chemical calculations shows that, the EHOMO as an electron donor of SOLE donate electrons to appropriate acceptor molecules to the vacant d orbital of Fe atoms of MS. Un-filled 3d orbital of MS could bind with HOMO of the inhibitors. On the other hand filled 4s orbital could donate the electron to LUMO of the inhibitor as oftenly ELUMO indicates the ability of molecules to accept electrons. Variation of experimental temperature studies revealed that the stability of the protective layer decreased at higher temperature and corrosion activation energies increased in the addition of SOLE.

The Mass Change Designated Observable Study: Overview and Results

AbstractThe 2017–2027 United States National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space identified Mass Change (MC) as one of five Designated Observables (DOs) having the highest priority in terms of Earth observations required to advance Earth system science over the next decade. In response to this designation, NASA initiated several multi‐center studies, with the goal of recommending observing system architectures for each DO for implementation within this decade. This paper provides an overview of the Mass Change Designated Observable (MCDO) Study along with key findings. The study process included: (a) generation of a Science and Applications Traceability Matrix (SATM) that maps required measurement parameters to the DS Science and Applications Objectives; (b) identification of three architecture classes relevant for measuring mass change: Precise Orbit Determination (POD), Satellite‐Satellite‐Tracking (SST) and Gravity Gradiometry (GG), along with variants within each architecture class; and (c) creation of a Value Framework process that considers science value, cost, risk, schedule, and partnership opportunities, to identify and recommend high value observing systems for further in‐depth study. The study team recommended the implementation of an SST architecture, and identified variants that simultaneously (a) satisfy the baseline measurement parameters of the SATM; (b) maximize the probability of providing overlap with the Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO) mission currently in operation, accelerating science return from both missions; and (c) provide a pathway towards substantial improvements in resolution and accuracy of mass change data products relative to the program of record.