Relative Density Research Articles

Undrained cyclic responses of sandy soils improved by soybean-induced calcium carbonate precipitation

ABSTRACT This study investigates the behaviour of sandy soils under cyclic conditions, emphasising the efficacy of soybean-induced calcium carbonate precipitation (SICP) treatment in mitigating liquefaction. Analysis of shear wave velocity and undrained cyclic responses was conducted, with a focus on understanding deformation response and development of excess pore pressure. Results revealed CaCO3 content as a definitive indicator for improvements in soil stiffness, with its distribution influenced by soil’s relative density and number of SICP injections. Enhanced cementation efficacy was observed in denser or deeper layers of sand column, attributed to prolonged SICP retention. A marked correlation between shear wave velocity and CaCO3 content highlighted SICP’s role in enhancing the liquefaction resistance of loose sandy soils. Dynamic triaxial testing showed the nuanced strain behaviours across varying relative densities and cyclic stress ratio (CSR) values, emphasising the strengthening influence of CaCO3 formations in the soil matrix. The empirical equation served as a testament to the potential of SICP in soil stabilisation endeavours. The intervention of SICP treatment presents a potent tool for bolstering soil stability, especially in regions susceptible to seismic activities. The insights garnered advocate for further research aimed at harnessing and optimising this soil improvement technique on a global scale.

Effect of pressure, temperature, and particle size on cold sintered ZnO for transparent thick films on polymer substrates

AbstractThe role of pressure, temperature, and particle size on cold sintering of ZnO has been investigated with a view to developing transparent thick films for device applications. Coarse ZnO (∼90–250 nm, cZnO) particles exhibited equiaxed grain growth under all conditions eventually achieving grain sizes of ∼ 0.5–1.0 µm at 300°C/375 MPa. In contrast, nano‐ZnO (40–80 nm, nZnO), exhibited grain growth along the c‐axis with a broader grain size distribution (0.5–4 µm) at higher temperatures and pressure (300°C/375 MPa) than cZnO. The broader grain size distribution is attributed to greater dissolution for nZnO compared with cZnO coupled with redistribution of Zn acetate/acetic acid into pores. ZnO continues to dissolve and reprecipitate within the pores throughout the densification process resulting in localized, larger grain sizes. In plane grain growth normal to the pressing direction was observed at and near the sample surface particularly in nZnO, which is attributed to constrained‐sintering. Some abnormal grain growth (10–20 µm) was also sporadically observed near or at the surface of nZnO (300°C/375 MPa) due to greater rates of reprecipitation as the transient solvent volatilizes adjacent to the die wall/plunger. Tape casting was used to fabricate single and multiple layers (≈30 µm) of ZnO on Kapton® to demonstrate the potential for device fabrication. Transparency was achieved by choosing cold sintering conditions (200°C/250 MPa) for nZnO that gave ∼95% relative density while restricting a majority of grain growth to <200 nm so that internal light scattering from grain boundaries was avoided.

Ultrasound-assisted extraction of sumac fruit oil and analysis of its fatty acid composition.

The use of ultrasound for enhancing the extraction of sumac fruit oil was investigated to maximize the utilization of available sumac fruit resources. The optimal extraction parameters were determined using single-factor trials and Box-Behnken design optimization and were found to be a liquid-to-material ratio of 13:1mL/g, an ultrasound temperature of 47°C, and an ultrasound duration of 32min. These yielded a 20.59% extraction rate of the oil. The ultrasonic-assisted approach markedly increased the extraction rate and significantly reduced the extraction time when compared to classical Soxhlet extraction. The resulting sumac fruit oil had a brown-yellow color with peroxide, acid, and iodine concentrations of 2.43mg/g, 0.44g/100g, and 135g/100g, respectively, and relative density (d20 20), and refractive index (20°C) values of 0.911, and 1.469, respectively. The primary fatty acids in the oil were stearic, linoleic, palmitic, linolenic, and oleic acids. With a 74.14% unsaturated fatty acid content, it has a high nutritional value as well as significant development and usage potential. PRACTICAL APPLICATION: This study demonstrates a highly efficient method for extracting vegetable oils and fats. It has the advantages of simple operation, low extraction temperature, short extraction time, high extraction rate, no damage to the material structure, excellent phusicai and chemical properties of the extracted vegetable oil, low cost, and the potential application in the food industry is crucial.

Densification, deformation, and delamination during co‐sintering process of metal–ceramic laminates

AbstractToday, there is a high demand and increasing trend for multifunctional composite materials and components due to the combination of a wide range of favorable properties. However, undesired deformation leading to delamination, curvature, cracks, or even complete fracture frequently occurs during the co‐sintering process of metal–ceramic laminates (MCLs). To solve these issues, experimental work highly relies on the time‐consuming trial‐and‐error principle. This work aims to develop a thermo‐mechanical‐metallurgical model capable of predicting the densification, deformation, and delamination of MCLs during the co‐sintering process. It is found that the developed model successfully considers the inhomogeneous relative density distribution and phase transformation of the steel tape. In addition, a thin interlayer formed by a mixed slurry in the MCLs is modeled as cohesive elements to simulate the delamination process. The developed model is systematically validated by the experimental measurements and observations in terms of densification, deformation, and delamination during the co‐sintering process of the investigated laminate variants.

Ecological Assessment of Weed Species in Two Secondary Forests in Anambra State Nigeria

An ecological study was done on weed species in two secondary forests present in Nnamdi Azikiwe University, Awka Campus and Federal College of Education Umunze, Anambra State, Nigeria. Data was collected from the two study sites which were randomly divided for adequate coverage and proper representation. Species dominance, abundance and diversity of weed species were recorded. The result of the study showed that a total of 21 weed species were recorded in Plot 1 study area which is at Nnamdi Azikiwe University, Awka campus; Pennisetum purpureum had the highest species abundance in the study site, with a total frequency of 93 and Dominance index of 28.97. Pennisetum purpureum had a relative density of while Tridax procumbens was the second most abundant with a frequency of 40 and Dominance of 7.10. Rhynchospora corymbosa showed the least abundance with a frequency of 6. The result of Shannon Wiener index for weed species in Plot 1 study was 2.56 and this showed that there is high diversity of weed species in the study area. Meanwhile, the result of the study in Plot 2, which is at Federal College of Education, Umunze showed that a total of 18 weed species were recorded; Imperata cylindrica had the highest species abundance in the study site, with a total frequency of 87 and Dominance index of 27.43, while Cypertrus rotundus was the second most abundant with a frequency of 67 and Dominance index of 10.5. Acanthus Montana showed the least in abundance with a frequency of 6 and Dominance index of 1.02. The result of Shannon Wiener index for weed species in Plot 2 study was 2.47 and this also showed that there is high diversity of weed species in the study area. This result invariably indicates a great potential for utilization in conservation and ecological purposes.

Rapid growth rate of Enterobacter sp. SM3 determined using several methods

BackgroundBacterial growth rate, commonly reported in terms of doubling time, is frequently determined by one of two techniques: either by measuring optical absorption of a growing culture or by taking samples at different times during their growth phase, diluting them, spreading them on agar plates, incubating them, and counting the colonies that form. Both techniques require measurements of multiple repeats, as well careful assessment of reproducibility and consistency. Existing literature using either technique gives a wide range of growth rate values for even the most extensively studied species of bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This work aims to apply several methods to reliably determine the growth rate of a recently identified species of Enterobacteriaceae, called Enterobacter sp. SM3, and to compare that rate with that of a well-known wildtype E. coli strain KP437.ResultsWe extend conventional optical density (OD) measurements to determine the growth rate of Enterobacter sp. SM3. To assess the reliability of this technique, we compare growth rates obtained by fitting the OD data to exponential growth, applying a relative density method, and measuring shifts in OD curves following set factors of dilution. The main source of error in applying the OD technique is due to the reliance on an exponential growth phase with a short span. With proper choice of parameter range, however, we show that these three methods yield consistent results. We also measured the SM3 division rate by counting colony-forming units (CFU) versus time, yielding results consistent with the OD measurements. In lysogeny broth at 37oC, SM3 divides every 21 ± 3 min, notably faster than the RP437 strain of E. coli, which divides every 29 ± 2 min.ConclusionThe main conclusion of this report is that conventional optical density (OD) measurements and the colony-forming units (CFU) method can yield consistent values of bacterial growth rate. However, to ensure the reproducibility and reliability of the measured growth rate of each bacterial strain, different methods ought to be applied in close comparison. The effort of checking for consistency among multiple techniques, as we have done in this study, is necessary to avoid reporting variable values of doubling time for particular species or strains of bacteria, as seen in the literature.

Evaluating the role of urine chemistry in shock wave lithotripsy outcomes.

Extracorporeal Shock Wave Lithotripsy (ESWL) is a commonly used method for the noninvasive treatment of kidney stones. However, achieving optimal treatment outcomes and minimizing potential damage to the kidney necessitates careful consideration for the total amount of energy utilized. This study aims to investigate whether urine pH and urine specific gravity have an impact on the total amount of energy applied during SWL. Between January 2023 and December 2023, 129 patients with renal stones underwent SWL in our department using the Storz Medical Modulith Inline lithotripter. Stone-free rates, complications, and the impact of patient, urine, and stone characteristics on energy use were analyzed. Urine samples were analyzed for pH and specific gravity. Stone characteristics, including size, HU, and skin-to-stone distance, were recorded. The obtained data were evaluated regarding the possible relationship between the total energy amount (determined as a risk factor) and the age, BMI, urine pH, urine specific gravity, stone size, HU, and skin-to-stone distance by using the Pearson correlation coefficient. p-value of < 0.05 was considered statistically significant. Evaluation of our findings revealed a negative linear relationship between total amount of energy used and the urine pH, indicating a decrease in the total energy amount as urine pH shifts towards alkaline values (p = 0.038; p < 0.05). However, no statistically significant relationship was observed between age, BMI, urine specific gravity, stone size, HU, and skin-to-stone distance and the total energy amount. Our findings demonstrated a significant relationship between urine pH and the total amount of energy applied during SWL sessions, suggesting the need for further prospective research to better understand the possible association between these two parameters. Such investigations could contribute to the development of more reasonable and effective strategies for kidney stone treatment in an attempt to minimize the potential kidney damage.

Geoinformatics and Modeling Approaches for Estimating Above-Ground Biomass in the Moist Deciduous Forests of Uttara Kannada, Karnataka, India

The present study aims to estimate Above-Ground Biomass (AGB) in the moist deciduous forests of Mundgod Taluk, Uttara Kannada district, Karnataka, India using a combination of field sampling and remote sensing techniques. AGB was assessed using Sentinel-2A satellite imagery with a spatial resolution of 10 meters. Field data were collected using the Point-Centered Quarter (PCQ) method, it includes measuring tree girth at breast height (GBH), tree height, and canopy density. AGB was calculated using artificial form factor and specific gravity of tree species and further modelled using the Normalized Difference Vegetation Index (NDVI) derived from satellite data. The results showed a significant correlation between canopy density and biomass, with very dense forests exhibiting the highest AGB values. The field-measured AGB was 436.96 t/ha for very dense forests, 259.89 t/ha for moderately dense forests, and 161.67 t/ha for open forests. A linear regression model developed between AGB and NDVI showed a high R² value of 0.91 for open forests, 0.87 for moderately dense forests, and 0.85 for very dense forests. The total area-weighted biomass for the study area was estimated at 8.87 million tons, with 4.79 million tons in very dense forests, 3.44 million tons in moderately dense forests, and 0.76 million tons in open forests. The regression model validation indicated low Root Mean Square Error (RMSE) values, with the moderately dense forests 8.81 t/ha and the in very dense forests 7.54 t/ha. This study highlights the effectiveness of integrating field measurements with remote sensing for rapid, reliable AGB estimation. The approach offers valuable insights into biomass distribution and carbon sequestration potential, providing a scalable method for carbon inventories at state and national levels, contributing to forest management and climate change mitigation efforts.

Translucent zirconia dental prosthesis processed by Direct Ink Writing: Updates and challenges

Direct ink writing (DIW) is an extrusion-based additive manufacturing technique, which uses a layer-by-layer deposition of an ink, usually containing high solid loads and low concentration of additives, to provide plasticity and structural stability for the construction of near-net-shaped pieces. In this work, a zirconia stabilized with 5 mol% Y2O3 colloidal ink was developed aiming to obtain dense prototypes, partially translucent, with potential for making dental prostheses. Cylindrical pieces (Ø 20 mm × 2.5 mm), prismatic bars (55 × 5 × 4 mm) and 3-element dental prostheses were printed based on Computer-aided design (CAD) models, using a printing speed of 10 mm.s−1 and a nozzle with Ø 0.25 mm. The printed samples were dried at strictly controlled conditions, debinded using an optimized thermal cycle, and sintered at 1600 °C-2 h. The sintered parts were characterized by X-ray diffraction, scanning electron microscopy, Vickers hardness, fracture toughness and bending strength. Concerning dental prosthesis, a post-processing finishing strategy was performed on pre-sintered bodies to highlight the anatomical details. After sintering, samples presented relative density around 94–95 %, Vickers hardness, fracture toughness and Young Modulus of 12.7 ± 0.3GPa, 5.31 ± 0.21 MPa.m1/2 and 195.4 ± 45 GPa, respectively. A characteristic strength (σ0) of 303 MPa was attained, which is above the requirements for its application as ceramic single-unit dental prostheses. A critical analysis of the technological difficulties of this 3D printing technique for manufacturing dental prostheses is presented, while future directions are addressed.

Impact of Vertical Vibration on Group Piles During Earthquake Loading: Experimental Findings

This study presents novel research on the impact of vertical vibration on the dynamic response of pile groups embedded in stratified soil under seismic loading conditions. An experimental setup was employed wherein the piled machine foundation was subjected to vertical vibrations at three operating frequencies (10, 20, and 30 Hz) and subsequently exposed to four levels of seismic acceleration (0.1 g, 0.34 g, 0.77 g, and 0.82 g). Piles with a length-to-diameter ratio of 25 were embedded in a stratified soil profile, with an upper loose layer (30% relative density) and a lower dense layer (80% relative density) acting as end-bearing. Measurements and analyses of horizontal and vertical accelerations, and amplification factors were conducted using the Fast Fourier Transform (FFT), spectral acceleration (Sa), and variation of acceleration with depth. The results demonstrated a significant reduction in horizontal acceleration, with a peak ground acceleration (PGA) reduction of up to 64% in average, particularly at higher frequencies such as 30 Hz. The mitigation efficiency at 30Hz improved with increasing PGA, showing reductions of 42, 68, 75, and 63% for seismic accelerations of 0.1 g, 0.34 g, 0.77 g, and 0.82 g, respectively. The analysis further revealed harmonic resonance and higher mode effects at lower frequencies, with nonlinear soil behavior affecting the resonance and amplification patterns. Additionally, the results demonstrate that the far-field accelerations exceeded the near-field accelerations within the pile group, particularly in the surface layer. The results indicated that the initial vibration amplitudes exceeded the safe operating limits outlined in ACI 351.3R-18 under seismic loading, particularly at higher seismic acceleration levels and lower frequencies. Additional modified charts were presented to account for these conditions. The results presented promising evidence for using vertical vibrations as an earthquake-mitigation strategy. However, avoiding operating at frequencies less than 10 Hz is recommended because of the potential resonance and interaction with horizontal accelerations during earthquakes. Doi: 10.28991/CEJ-SP2024-010-010 Full Text: PDF

Liquefaction and reliquefaction mitigation of sand specimen treated with prefabricated vertical drains: An experimental investigation

This study examines the performance of prefabricated vertical drains (PVD) against liquefaction and reliquefaction. A series of 102 shakings were performed using 1g shaking table apparatus on untreated and treated sand specimens prepared with 25% relative density. Sinusoidal waveform experimented with three different repeated shaking patterns and independent events for two different frequencies (2 Hz and 3.5 Hz) with 1-min duration. Two different installation methods; drainage alone method (PVD-D) and drainage along with densification (PVD-DD) were experimented. Durability of PVD were examined from geotextile tensile testing apparatus and digital image correlation. These experiments demonstrated excellent durability characteristics of PVD filter even after exposed to repeated shakings. Treated specimens improved the resistance to reliquefaction due to radial drainage offered by PVD which has retarded the excess pore pressure (EPP) generation. In addition, densification induced during the installation of PVD also contributed for restricting EPP, however, the induced sand densification achieved during repeated shaking events were not responsible for increased resistance against liquefaction/reliquefaction. Results indicate that the maximum pore pressure ratio in treated specimens were restricted within threshold design limit (≤0.60) for most of the events, even when the untreated specimens completely liquefied or generated a maximum value near unity.

Stick, Slide, or Bounce: Charge Density Controls Nanoparticle Diffusion.

The diffusion and interaction dynamics of charged nanoparticles (NPs) within charged polymer networks are crucial for understanding various biological and biomedical applications. Using a combination of coarse-grained molecular dynamics simulations and experimental diffusion studies, we investigate the effects of the NP size, relative surface charge density (ζ), and concentration on the NP permeation length and time. We propose a scaling law for the relative diffusion of NPs with respect to concentration and ζ, highlighting how these factors influence the NP movement within the network. The analyses reveal that concentration and ζ significantly affect NP permeation length and time, with ζ being critical, as critical as concentration. This finding is corroborated by controlled release experiments. Further, we categorize NP dynamics into sticking, sliding, and bouncing regimes, demonstrating how variations in ζ, concentration, and NP size control these behaviors. Through normalized attachment time (NAT) analyses, we elucidate the roles of electrostatic interactions, steric hindrance, and hydrodynamic forces in governing NP dynamics. These insights provide guidance for optimizing NP design in targeted drug delivery and advanced material applications, enhancing our understanding of NP behavior in complex environments.

Cu/AlN composite and functionally graded materials with high strength and high electrical- and thermal-conductivity fabricated by spark plasma sintering

Abstract In this study, Cu/AlN composites and functionally graded materials (FGMs) were fabricated with the spark plasma sintering (SPS) method. It was observed that a two-step sintering process, involving sintering under low pressure as the initial stage to remove adsorbed chemicals on the powder, was an effective method for producing sintering objects with high relative density. The hardness of the composites significantly increased with higher volume fraction of AlN particles, while electrical- and thermal-conductivity decreased. Nevertheless, the advanse impact of AlN on thermal-conductivity was found to be minimal. Additionally during compression test, a crack was noted at the interface between Cu and Cu-5vol%AlN region in two-layered FGMs after, whereas no such crack was observed in the three-layered FGMs. Therefore, it is confirmed that the concept of FGMs is useful in overcoming the shortcomings of mutually exclusiveness among high strength, high electrical- and high thermal-conductively.

Powder bed fusion of solid and permeable Crofer 22 APU parts for applications in chemical process engineering

AbstractAdditive manufacturing of metals has attracted significant attention across various industries. However, its adoption in certain chemical and energy sectors remains constrained by the absence of optimized alloys tailored for high temperatures and corrosive environments. This study explores the laser-based powder bed fusion processing of Crofer 22 APU, a high-temperature, corrosion-resistant alloy ideal for applications such as methane steam reforming reactors, high-temperature fuel cells, and palladium membrane supports. Systematic optimization of laser parameters including laser power, hatch distance, point distance, and building angles was conducted for both dense and porous objects. Dense parts achieved a relative density of 0.9999 and surface roughness of Sa= 41.27±1.48 on a 45$$^\circ$$ ∘ overhang. Porous samples showed a porosity range of 28.655.5% and surface roughness Sa 22.2 $$\upmu$$ μ m to 45.9 $$\upmu$$ μ m as hatch distance increased from 0.12 mm to 0.16 mm. Additionally, an 8YSZ coating applied via screen printing demonstrated the impact of hatch distance and laser power on surface quality. The combination of additive manufacturing of Crofer 22 APU and screen printing of 8YSZ simplifies the preparation of metallic supports for Pd-based membranes, reducing fabrication time and cost by shortening the number of preparation steps. This technique offers a promising approach for scaling up membranes and membrane reactors.

Comparative Microstructure Characteristics of Synthesized PbS Nanocrystals and Galena

Lead sulfide (PbS) on the nanoscale was synthesized via a chemical route at room temperature using lead nitrate {Pb(NO3)2} and sodium sulfide (Na2S). The Na2S was prepared at ~105 °C using sodium hydroxide (NaOH) and sulfur (S) powder. The produced PbS, denoted as Lab-PbS, was compared with a high-concentration PbS phase of galena. The produced Na2S and Lab-PbS were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy for microstructural and chemical analysis. The results confirmed a high-purity PbS compound (&gt;99%) with a nanoscale particle size. The results showed that ultrasonic agitation was vital for obtaining the nanoparticle size of the Lab-PbS. Furthermore, thin films from the synthesized Lab-PbS and galena were successfully thermally evaporated on glass, quartz, and silicon substrates. The formation of nanometric grains was confirmed by scanning electron microscopy (SEM). XRD and FTIR spectroscopy were carried out for the Lab-PbS, galena fine powders, and galena thin films. The average crystal diameter was calculated for the galena thin films and was found to be approximately 26.6 nm. Moreover, the UV–Visible transmission curve was measured for the thin films in the wavelength range of 200–1100 nm in order to calculate the bandgap energy (Eg) for the thin films. The values of Eg were approximately 2.65 eV and 2.85 eV for the galena and Lab-PbS thin films, respectively. Finally, the sintering of the Lab-PbS and galena powders was carried out at ~700 °C for 1 h under vacuum, achieving relative densities of ~98.1% and ~99.2% for the Lab-PbS and galena, respectively.

Contribution of an Automatic Algorithm for Quantifying the Volume of Aneurysmal Subarachnoid Hemorrhage to the Evaluation of the Risk of Occurrence of Delayed Cerebral Ischemia: A Cohort Study.

This study focuses on aneurysmal subarachnoid hemorrhage (aSAH) with a high risk of delayed cerebral ischemia (DCI) and acute hydrocephalus (AH). The aim was to compare the performance of an automatic algorithm for quantifying the volume of intracranial blood with the reference radiological scales to predict DCI, AH, and neurological outcome. This was a single-center retrospective observational study of a cohort of patients with aSAH. We developed an automated blood detection algorithm based on the specific density of the blood clot. The blood clot was segmented on the first brain scan (total, supratentorial, cisternal, intraventricular). The predictive value of our model was compared, using the area under the receiver operating characteristic curve (ROCAUC), to eight radiological scales: Fisher, modified Fisher, Claassen, Barrow Neurological Institute, Hijdra, Graeb, LeRoux scales, and intraventricular hemorrhage score. We analyzed the scans of 145 patients with aSAH. In our cohort, 51 patients (43%) had DCI and 70 patients (54%) had AH. At 3 months, 22% of patients had died and 19% had poor outcome (Glasgow Outcome Scale extended 2-4). Cisternal blood volume was significantly correlated with cisternal Hijdra scale (R2 = 0.79; P < 0.001). The ROCAUC of cisternal blood volume was comparable to the ROCAUC of the Hijdra scale in predicting the occurrence of DCI (ROCAUC = 0.83 [95% confidence interval {CI} 0.75-0.89] vs. 0.86 [95% CI 0.79-0.9]; P = 0.23). The ROCAUC of intraventricular blood volume was not significantly different from the intraventricular hemorrhage score in predicting the occurrence of AH (ROCAUC = 0.78 [95% CI 0.70-0.84] vs. 0.79 [95% CI 0.72-0.85]; P = 0.28). The ROCAUC and supratentorial blood volumes were not significantly different from the Simplified Acute Physiology Score II in predicting the occurrence of poor neurological outcome at 3 months (ROCAUC = 0.75 [95% CI 0.67-0.82] vs. 0.81 [95% CI 0.74-0.87]; P = 0.073). With no manual intervention, our algorithm performed as well as the best radiological scores in predicting the occurrence of DCI, AH, and neurological outcome.

Super Chloride Ionic Conductivity in CsSnCl3‐Based Perovskite Compound and Its Application for Solid‐State Chloride Batteries

A CsSnCl3‐based solid electrolyte in which 5% of Sn sites are occupied by Y ions, CsSn0.95Y0.05Cl3.05 (CSYC), is developed using a one‐step mechanical ball‐milling method. CSYC exhibits a stable cubic perovskite crystal structure and a high chloride ion conductivity of 4.9 mS cm−1. The relative density of a CSYC pellet following cold pressing without heat treatment is 97.5%. The high relative density and ionic conductivity are considered to originate from the high mechanical plasticity of the pellets, as evidenced by a low Young's modulus of 8.2 GPa. An all‐solid‐state chloride ion battery cell using CSYC as the electrolyte, BiCl3 as the active cathode material, and Sn as the anode is confirmed to operate at room temperature. The cell shows a large initial discharge capacity of 178 mAh g−1, ≈70% utilization, and good capacity retention with a reversible capacity of 100 mAh g−1 after 40 cycles. The mechanical plasticity of CSYC is considered to be a major contributor to its high ionic conductivity and good battery cycling performance.

Crashworthiness study of polyamide bi-tubular thin-walled tubes using hybrid lattice filling

Thin-Walled Tubes (TWT) are widely used as crashworthiness elements to absorb and dissipate kinetic energy during collision through plastic deformation. Various design strategies, including nested tubes, triggers, and filling with lattices, are commonly used to enhance the crashworthiness of TWT. Additive Manufacturing (AM) offers unique opportunities to produce complex lattice-filled TWT with higher precision, but challenges persist in the design and fabrication of bi-tubular TWT to enhance crashworthiness. The aim of this study is to propose an approach for hybrid lattice filling in bi-tubular structures. In the preliminary phase, the parametric study was conducted to understand the influence of tube cross-section geometry, thickness, and trigger hole diameter on the crashworthiness of empty TWT using Taguchi’s L9 orthogonal array. Empty TWTs were fabricated using Selective Laser Sintering (SLS) with PA12 material and compressed uni-axially at 8 mm/min speed. In the second phase, bi-tubular TWT was filled with three different unit cells such as Cube, Kelvin, and Octet Truss (OT) having 30% relative density. In the lattice filling approach, two different strategies were followed such as uniform and hybrid lattice filling. Designed TWTs were fabricated and tested under uni-axial compression at two different speeds such as 8 mm/min and 8 mm/sec. Based on the results of the preliminary study, it has been observed that cross-section geometry and tube thickness significantly enhance SEA through an increase in the stiffness and number of folding. With the help of the Signal to Noise (S/N) ratio graph, appropriate levels were selected as input for the hybrid lattice-filling approach. The results of the second phase revealed that hybrid lattice filling significantly enhances the deformation modes, energy absorption, and crashworthiness properties of TWTs. Hybrid lattice-filled TWT offers better Specific Energy Absorption (SEA) as 18.32 kJ/kg at 8 mm/sec compression speed, which is 113.9% higher than empty and 42.8% higher than uniform lattice-filled TWT. This work demonstrated that adopting the hybrid lattice-filling approach is one of the potential ways to enhance the crashworthiness of protective equipment such as crash boxes and frames.

Non-REM sleep slow wave activity features are associated with amyloid accumulation in older adults with obstructive sleep apnea

Abstract Obstructive sleep apnea (OSA) is associated with an increased risk for cognitive impairment and dementia, which likely involves Alzheimer’s disease (AD) pathology. Non-rapid eye movement (NREM) slow wave activity (SWA) has been implicated in amyloid clearance, but it has not been studied in the context of longitudinal amyloid accumulation in OSA. This longitudinal retrospective study aims to investigate the relationship between polysomnographic (PSG) and electrophysiological SWA features and amyloid accumulation. From the Mayo Clinic Study of Aging cohort, we identified 71 participants &amp;gt;=60 years old with OSA (mean baseline age=72.9 ± 7.5 years, 60.6% male, 93% cognitively unimpaired) who had at least two consecutive Amyloid Pittsburgh compound B (PiB)-PET scans and a PSG study within 5 years of the baseline scan and before the second scan. Annualized PiB-PET accumulation (global ΔPiB[log]/year) was estimated by the difference between the second and first log-transformed global PiB-PET uptake estimations divided by the interval between scans (years). Sixty-four participants were included for SWA analysis. SWA was characterized by the mean relative spectral power density (%) in slow oscillation (SO) (0.5-0.9 Hz) and delta (1-3.9 Hz) frequency bands, and by their downslopes (SO-slopes and delta-slope, respectively) during the diagnostic portion of PSG. We fit linear regression models to test for associations between global ΔPiB(log)/year, SWA features (mean SO% and delta% or mean SO-slope and delta-slope), and OSA severity markers, after adjusting for age at baseline PiB-PET, APOE ε4, and baseline amyloid positivity. For 1 s.d. increase in SO% and SO-slope, global ΔPiB(log)/year increased by 0.0033 (95% CI 0.0001; 0.0064, p=0.042) and 0.0069 (95% CI: 0.0009; 0.0129, P=0.026), which were comparable to 32% and 59% of the effect size associated with baseline amyloid positivity, respectively. Delta-slope was associated with a reduction in global ΔPiB(log)/year by -0.0082 (95% CI: -0.0143; -0.0021, P=0.009). Sleep apnea severity was not associated with amyloid accumulation. Regional associations were stronger in the prefrontal region. Both slow wave slopes had more significant and widespread regional associations. Annualized PiB-PET accumulation was positively associated with SO and SO-slopes, which may reflect altered sleep homeostasis due to increased homeostatic pressure in the setting of unmet sleep needs, increased synaptic strength and/or hyperexcitability in OSA. Delta-slope was inversely associated with PiB-PET accumulation, suggesting it may represent residual physiological activity. Further investigation of SWA dynamics in the presence of sleep disorders before and after treatment is necessary for understanding the relationship between amyloid accumulation and SWA physiology.

Evaluation of tuber quality, yield and yield related traits of potato (Solanum tuberosum L.) genotypes at Holetta, Central Ethiopia

In Ethiopia, potato is a food security and income generating crop for millions of smallholder farmers. Previous research efforts related to variety development was focusing on tube yield and late blight resistance with wide adaptability. So far, the potato research program in the country however, devoted less on tuber quality traits and processing parameters except few recently released varieties that considered tuber quality traits for processing. These few potato varieties with processing qualities not yet satisfied the ever-emerging processing industries for chips and French fries in the country. Hence, this study aimed to seek evaluating more potato genotypes that have merits for tuber quality traits used for processing and yield attributes. The experiment was laid out in a randomized completed block design with three replications using 24 potato genotypes to evaluate the processing quality traits of advanced potato genotypes at Holetta Agricultural Research Centre in 2017 main cropping season. The results of the analysis of variance revealed that all the traits showed significant differences among the genotypes indicating there is wide genetic variation. The highest and significantly different tuber physical quality traits of geometric mean diameter and surface area was recorded from CIP395017.229, sphericity of the tuber from CIP396027.205, and length to width ratio from CIP399075.7. The specific gravity of tubers, dry matter content and total starch content also ranged from 1.070 to 1.103 gcm−3, 18.67 to 25.75%, and 12.64% to 18.95%, respectively. The five advanced genotypes CIP398098.65, CIP392617.54, CIP398190.404, CIP394611.112, and C398190.89 were selected for their high total tuber yields over 36.80 t/ha, with more than 31.47 t/ha marketable tuber yield, greeter than 69.92 g/tuber average tuber weight, higher than 58.41 mm3 geometric mean diameter, more than 21.25% dry matter content, excellent tuber characteristics and processing quality traits for chips and French fries making. From this study, selection of potato genotypes that consider both external and internal tuber quality traits would expedite the process of advancing ample potato varieties with processing qualities in the country considering comprehensive study by including more potato genotypes across wider growing environments.