Dry Samples Research Articles

The influence of water-saturation on the strength of volcanic rocks and the stability of lava domes

The rocks forming a volcanic edifice or dome are typically saturated or partially-saturated with water. However, most experiments aimed at better understanding the mechanical behaviour of volcanic rocks have been performed on dry samples, and therefore most large-scale models designed to explore volcano stability have used parameters representative for dry rock. Here, we present a combined laboratory and modelling study in which we (1) quantified the influence of water-saturation on the mechanical behaviour of variably altered dome rocks from La Soufrière de Guadeloupe (Eastern Caribbean) and (2) used these new data to investigate the influence of water on dome stability. Our laboratory data show that the ratio of wet to dry uniaxial compressive strength (UCS) and Young's modulus are ∼0.30–0.95 and ∼0.10–1.00, respectively. In other words, the dome rocks were all mechanically weaker when water-saturated. Further, the ratio of wet to dry UCS decreased with increasing alteration (the wt% of secondary minerals in the rocks). Micromechanical modelling suggests that the observed water-weakening is the result of a decrease in fracture toughness (KIC) in the presence of water. The ratio of wet to dry KIC also decreases with increasing alteration, explaining why water-weakening increased as a function of alteration. To explore the influence of water-saturation on lava dome stability, we numerically generated lava domes in Particle Flow Code using the experimental data corresponding to unaltered and altered rock under dry conditions. The strength of the dome-forming rocks was then reduced to values corresponding to wet conditions. Our modelling shows that, although the stability of the unaltered dome was not influenced by water-saturation, larger displacements were observed for the wet altered dome. Additional simulations in which we modelled a buried alteration zone within an otherwise unaltered dome showed that higher displacements were observed when the dome was water-saturated. We conclude that (1) the water-saturation reduces the UCS and Young's modulus of volcanic rock, (2) larger decreases in UCS in the presence of water are observed for altered rocks, and (3) the stability of a dome can be compromised by the presence of water if the dome is altered, or contains an altered zone. These conclusions highlight that the degree of alteration and water-saturation should be mapped and monitored at active volcanoes worldwide, and that large-scale models should use values for water-saturated rocks when appropriate.

Shear yielding and crazing in dry and wet amorphous PLA at body temperature

Understanding the inelastic, rate-dependent mechanical response of biodegradable polymers is important for the design of load-bearing biodegradable structures with controlled deformation and failure response. In this study, we investigate the mechanical response of amorphous polylactic acid (PLA) in dry and wet conditions prior to the onset of degradation at body temperature. The presence of water decreases the glass transition temperature by 4.5 °C, the storage modulus by 21%, and the compressive and tensile yield strengths by about 10%, despite a small water uptake of 0.93 wt%. The tensile response of PLA is dominated by craze yielding, rather than shear plasticity, and is stable against necking despite pronounced strain softening and local strain heterogeneities measured by Digital Image Correlation (DIC). Further analysis of the DIC strain fields in dry and wet samples suggests a transition from pure craze yielding in dry samples to a coexistence of craze yielding and shear plasticity in wet samples. The mechanism shift between tension and compression behaviour of dry and wet PLA has implications for the design of load-bearing structures and for constitutive modelling.

Angle of repose for superquadric particles: Investigating the effects of shape parameters

This study develops a model for the angle of repose (AOR) of granular materials composed of non-spherical particles represented by a superquadric function featuring five distinct shape parameters. Our investigation integrates experimental and numerical analyses based on the lifting cylinder approach, using a total of 30 different particle shapes. Initially, we validate a superquadric-based discrete element method using spherical particles and two spheroidal particles, emulating m&ms and Pinto Beans. Subsequently, we examine the impact of each shape parameter on the AOR and heap geometry to identify the most influential parameters. We then construct the AOR model as a function of the particle aspect ratio defined using a combination of the shape parameters. To assess the accuracy and predictive capacity of the proposed AOR model, we conduct six blind tests involving particles with varying shapes and numbers. The results demonstrate a remarkable accuracy, with an average R2 value of 98.6%. Additionally, to showcase the practicality of the proposed AOR model, we apply it to estimate the internal friction angle and the soaked California Bearing Ratio (CBR) of dry sand samples. The results show estimation errors below one percent, underscoring the predictive accuracy and reliability of the model.

Atmospheric organic nitrogen deposition around the Danjiangkou Reservoir: Fluxes, characteristics and evidence of agricultural source

Dissolved organic nitrogen (DON) deposition was the substantial component of dissolved total nitrogen (DTN) deposition in the world's nitrogen deposition hot spots areas. However, the information on the importance for DON deposition and its sources was still scarce, which limited the comprehensive assessment of the ecological threat from nitrogen deposition. Six sampling sites around the Danjiangkou Reservoir were set up to collect the dry and wet deposition samples from October 2017 to September 2021. The results showed that dry and wet DTN deposition averaged 34.72 kg ha−1 yr−1 and 22.27 kg ha−1 yr−1, respectively. Dry NH4+-N, NO3−-N and DON deposition averaged 14.28 kg ha−1 yr−1, 5.91 kg ha−1 yr−1 and 14.53 kg ha−1 yr−1, respectively. Wet NH4+-N, NO3−-N and DON deposition averaged 11.14 kg ha−1 yr−1, 3.89 kg ha−1 yr−1and 7.24 kg ha−1 yr−1, respectively. The contributions of DON to DTN were 41.85% (in dry deposition) and 32.50% (in wet deposition), respectively. Dry DON deposition varied between 26.44 kg ha−1 yr−1 and 9.11 kg ha−1 yr−1, and significantly differed among six sampling sites (P < 0.05). The different intensity of agricultural activities disturbance at the sampling sites was the important reason for the spatial variations of DON deposition. DON deposition was significantly correlated with ammonium nitrogen (NH4+-N) deposition (P < 0.05). According to the results of positive matrix factorization (PMF) model, agriculture source contributed significantly to the DON deposition, the contributions at six sampling sites ranged from 45.8% to 73.7% in dry deposition, and from 56.8% to 81.6% in wet deposition. In summary, our findings found that agricultural activities were the important factors influencing the spatial patterns of DON deposition around Danjiangkou Reservoir and provided new evidence for the anthropogenic source of DON deposition in China.

Impact of Density, relative Humidity, and fiber size on hygrothermal properties of barley straw for building envelopes

Biosourced materials are increasingly considered to replace traditional insulators to reduce environmental impacts and benefit from better hygrothermal buffering characteristics. Barley straw is cheap and abundant and can be manufactured into insulation material. However, it is necessary to understand their hygrothermal properties as a function of manufacturing to design proper assemblies. The present work aims to determine experimentally and analyze sorption–desorption curves, thermal conductivity, water vapor permeability, and moisture buffer value (MBV) of barley straw as a function of density, fiber size, and relative humidity. Expressions were developed to correlate hygrothermal properties with the characteristics of the samples. Results revealed thermal conductivity values from 0.0468 W/mK (low-density short-fiber dry samples) to 0.0799 W/mK (low-density short-fiber 90 % RH samples) and MBV from 2.12 g/(m2 %RH) for high-density long-fiber samples to 2.95 g/(m2 %RH) for low-density short-fiber samples. The water vapor diffusion resistance factors ranged from 3.34 to 11.20 depending on the method used (wet versus dry) and the sample characteristics. These results indicate that straw offers a good potential as an insulator and indoor climate regulator in buildings.

Centesimal, Physico-Chemical, Bioactive and Microbiological Characterization of Pilsen-Type Malt Bagasse

Objective: This study aimed to characterize malt bagasse obtained as the main residue from beer processing. Theoretical benchmark: Malt bagasse is an agro-industrial waste with attractive nutritional characteristics, such as dietary fibers and proteins, intended for low or no added value purposes. In this sense, malt bagasse can nutritionally enrich various food products. Method: The malt bagasse was dehydrated and then analyzed for its central characteristics (moisture, ash, proteins, dietary fiber, lipids, carbohydrates, energy value and mineral composition), physicochemical (pH, acidity and aw), bioactive (phenolic and antioxidant content) and microbiological. Results and conclusion: As main results, malt bagasse showed high dietary fiber content (37,70 g/100 g) and high protein content (18,24 g/100 g), antioxidant capacity by the DPPH method with results expressed in EC50 as being 4,68 mg/mL and total phenolic content 360,99 mg EAG/100 g dry sample. Implications of the research: The results of this study show a promising potential in the reuse of malt bagasse, to quote, in the incorporation into food for human consumption.

Study on multi-performance optimization of basalt stone powder supplementary cementitious materials

In order to better apply basalt powder to supplementary cementitious materials (SCMs), this paper chooses the content of basalt stone powder, fly ash and slag as the influencing factors, and the 7d drying shrinkage rate, 28d drying shrinkage rate, fluidity, 7d and 28d compressive strength of mortar as the evaluation indexes of SCMs. Based on the response surface and multi-objective optimization method, the Box-Benken experimental design method was used to study the influence of the physical and chemical superposition of various factors on the properties of supplementary cementitious materials and optimize the ratio. The low-field nuclear magnetic resonance technique was used to detect the water change and porosity difference between the reference group and the optimization group at each age. The results show that the linear interaction and interaction of basalt powder, fly ash and slag have an effect on the strength, fluidity and drying shrinkage of cementitious materials. The optimal mixing ratio of basalt stone powder supplementary cementitious material is stone powder (10.8 %), fly ash (5 %) and slag (22.69 %). Under this mix ratio, the properties of basalt powder-assisted cementitious materials have been improved and close to the reference group. In the early hydration process, the physical filling effect of supplementary cementitious materials such as stone powder can better optimize the pore structure inside the slurry and the water loss is small, the strength is improved slowly, the dry shrinkage pure cement sample is similar, and the fluidity is improved. With the extension of hydration time, the water loss of the optimized group increased, and the strength and drying shrinkage increased.

Optimization of Ultrasound-Assisted Extraction and Characterization of the Phenolic Compounds in Rose Distillation Side Streams Using Spectrophotometric Assays and High-Throughput Analytical Techniques.

Lately, the essential oils industry has been one of the most expanding markets globally. However, the byproducts generated after the distillation of aromatic plants and their transformation to novel high-added value products consist of a major up-to-date challenge. Thus, the scope of the current study is the optimization of ultrasound-assisted extraction (UAE) for the recovery of phenolic compounds from rose (Rosa damascena) post-distillation side streams using Box-Behnken design. In particular, the highest total phenolic content (TPC) was achieved at 71% v/v ethanol-water solution, at 25 min, 40 mL/g dry sample and 53% ultrasound power, while ethanol content and extraction time were the most crucial factors (p-value ≤ 0.05) for UAE. Both solid (RSB) and liquid (LSB) rose side streams exhibited significant antiradical and antioxidant activities. The interpretation of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the presence of compounds with properties such as phenolic compounds, phenolic amide derivatives, and alcohols in the extracts. Moreover, the flavonoids naringenin, quercetin, and kaempferol were the major phenolic compounds, identified in the extracts by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS), followed by gallic, protocatechuic, p-hydroxybenzoic, and rosmarinic acids. Furthermore, the LC-MS/MS results pinpointed the effect of factors other than the extraction conditions (harvesting parameters, climatic conditions, plant growth stage, etc.) on the phenolic fingerprint of RSB extracts. Therefore, RSB extracts emerge as a promising alternative antioxidant agent in food products.

Dry blood spot samples to monitor immune-associated mRNA expression in intervention studies: Impact of Baker's yeast beta glucan.

Monitoring immunological response to physical stressors in a field setting is challenging because existing methods require a laboratory visit and traditional blood collection via venipuncture. The purpose of this study was to determine if our optimized dry blood spot (DBS) methodology yields sufficient total RNA to quantify the effect of Baker's Yeast Beta Glucan supplementation (BYBG; Wellmune; 250mg/d) on post-exercise mRNA expression. Participants had venous DBS samples collected prior to (PRE), and immediately (POST), 2 (2H), and 4 (4H) hrs after completion of a 90min run/walk trial in a hot, humid environment. Total RNA extracted from DBS was analyzed using a 574-plex Human Immunology mRNA panel (Nanostring). BYBG supplementation was associated with the increased expression of 12 mRNAs (LTB4R, PML, PRFM1, TNFRSF14, LCK, MYD88, STAT3, CCR1, TNFSF10, LILRB3, MME, and STAT6) and decreased expression of 4 mRNAs (MAP4K1, IKBKG, CD5, and IL4R) across all post-exercise time points. In addition to individually changed mRNA targets, we found eleven immune-response pathways that were significantly enriched by BYBG following exercise (TNF Family signaling, immunometabolism, oxidative stress, toll-like receptor (TLR) signaling, Treg differentiation, autophagy, chemokine signaling, complement system, Th2 differentiation, cytokine signaling, and innate immune). The present approach showed that DBS samples can be used to yield useful information about mRNA biomarkers in an intervention study. We have found that BYBG supplementation induces changes at the mRNA level that support the immune system and reduce susceptibility to opportunistic infection (i.e., upper respiratory tract infection) and facilitate improved physical recovery from exercise. Future studies may look to use DBS sampling for testing other nutritional, health, or medical interventions.

Evaluation of the thermal stability and transfer rate of pyrrolizidine alkaloids during the brewing of herbal infusions contaminated with Echium vulgare and Senecio vulgaris weeds

Pyrrolizidine alkaloids (PAs) are currently in the spotlight of food safety due to the potential health risk that their intake may entail for consumers. Among the wide variety of food products likely to be contaminated with PAs, teas and herbal teas stand out because of their cross-contamination with weeds from PA-producing plants. Accordingly, this work simulates the cross-contamination of chamomile tea samples with weeds of Senecio vulgaris and Echium vulgare to evaluate the effect of brewing on the PA content at different temperature (100 and 75 °C) and time (5 and 10 min) conditions. The results of the thermal degradation study revealed PAs are quite stable compounds under the conditions assayed, being the initial PA concentration the variable that strongly affected the thermal stability of these compounds, rather than the brewing temperature and time. On the other hand, it was confirmed that not all PAs are effectively transferred from the dry material to the infusion during the brewing process, leading to overall transfer rates between 13 ± 1 to 87 ± 10%. Also, it was observed that the extraction efficiency may be influenced by the type of matrix, since transfer rates were lower when the PA migration came from Echium vulgare than from Senecio vulgaris. Moreover, it was confirmed that the real content of PAs in a cup of tea can be overestimated in 2–7 times if their transfer rate is not considered during the brewing process, highlighting the importance of analyzing the infusion samples instead of the dry tea samples to correctly assess the risk exposure of consumers to these contaminants.

Hybrid calotropis gigantea fibre-reinforced epoxy composites with SiO2’s longer-term moisture absorbable and its impacts on mechanical and dynamic mechanical properties

Opportunities for the fabrication of plant fiber hybrids using thermoplastics and thermosets may be found in a variety of industries, including automobiles and agriculture. This can lessen reliance on crude oil, which contributes to a number of sustainability problems. In the current study, calotropis gigantea fiber (CGF) and nanosilicon dioxide (SiO2)-derived hybridized materials’ mechanical, dynamic mechanical, and water absorption properties were examined. Utilizing varying weight proportions of nanoSiO2 (0, 1.5, 3, and 4.5 wt%) and 30 wt% of CGF, we manufactured the composite using the hand lay-up method. The moisture absorption of the manufactured composites was measured during periods of 500, 1000, and 2000 h. For composite materials containing 1.5 wt% SiO2, the highest interlaminar shear strength (ILSS) failure point was 12.52 MPa for 500 h, which is 12.32% lower than the breaking strength for dried products (14.28 MPa). In comparison to the dry specimens, the bending strength of hybrids with 1.5% SiO2 that were immersed in water for 500, 1000, and 2000 h decreased by 2.56%, 5.21%, and 9.65%, respectively. The storage modulus of the damp hybrids with 3% and 4.5 wt% SiO2 was higher than that of the dry samples in terms of their dynamic mechanical properties. While the inclusion of nano-SiO2 significantly reduced water absorption and moisture diffusion, especially for hybrid materials with 4.5 weight percent SiO2, the water-absorption behaviour of hybrid natural fiber materials followed the Fickian law. With prolonged exposure time, the mechanical properties of the nanocomposite, both with and without nano-SiO2, such as ILSS and bending strength, declined. Due to the effective distribution of filler in the matrices, the samples with 4.5 weight percent SiO2 exhibited the smallest drop in strengths for both the flexural and interlaminar examinations, although all of them remained stronger than the CGF blends. The outcomes of the study point to potential applications in areas such as automobile manufacture, agriculture, construction, and general manufacturing.

Growth performance and secondary metabolite production of Adenostemma madurense using different fertilizers

Adenostemma madurense is one of the Asteraceae with many medical properties but has not been widely cultivated. This study aims to determine the different fertilizer doses that can produce the best growth, phenolic, flavonoid, terpenoid, and the 11α-OH KA (a diterpenoid found in A. madurense productivity), resulting in the high antioxidant capacity of A. madurense. A one-factor randomized block design was employed in five fertilizer doses, control/without fertilizer, 100 % cow manure (20 tons/ha), 100 % NPK (in the form of urea, SP-36, and KCl:135, 100, 135 kg/ha, respectively), a combination of 50 % cow manure + 50 % NPK, and a combination of 100 % cow manure + 100 % NPK. Fertilizers increase plant growth. Applying the combination of 100 % cow manure + 100 % NPK was the best fertilizer composition, which produced the highest plant height, leaf, and branch number. This fertilizer combination produced total phenolic, flavonoid productivity of 739.50 μmol Gallic Acid Equivalent/plant, 97.37 μmol Quercetin Equivalent/plant, not significantly different from applying 100 % NPK and the combination of 50 % cow manure + 50 % NPK, and terpenoid productivity of 77.51 mmol Nerol Equivalent/plant. The 11α-OH KA productivity and antioxidant capacity of this fertilizer is 18.00 mM 11α-OH KA/plant and 601.76 μmol Ascorbic Acid Equivalent/g dry sample, not significantly different from applying 100 % NPK. Applying 100 % cow manure + 100 % NPK may enhance the medicinal plant A. madurense’s efficacy, especially for antioxidants.

EFFECT OF BREWING TEMPERATURE AND TIME ON VITAMIN C CONTENT AND ANTIOXIDANT ACTIVITY OF EDIBLE FLOWER INFUSES

Dried chrysanthemum, jasmine and butterfly pea are raw materials for dip infused with antioxidant and vitamin C content. This study aimed to determine the effect of temperature and infusion time on vitamin C content and antioxidant activity. A two-factorial design was used with the first factor being the infusion temperature of 30, 50 and 70 °C. The second factor was infusion time of 1, 3 and 5 minute. Vitamin C content was determined by UV spectrophotometric method (Thermo Scientific Genesys 10 S UV), antioxidant activity by DPPH method, and moisture content by moisture analyzer. The optimum results of vitamin C content of dry samples at 30 °C brewing temperature for 3 minutes and 70 °C brewing temperature for 5 minutes was 0.29%. The vitamin C content of the wet flower control at 70 °C for 5 minutes was 0.53%. The optimum antioxidant activity of the dry sample at 50 °C brewing temperature for 3 minutes was 34.61% and that of the fresh flower control at 70 °C brewing temperature for 5 minutes was 94.14%. The moisture content of dried Chrysanthemum was 7.30%, dried Jasmine was 6.25% and dried butterfly pea was 7.24%.

Investigation of the effect of over-fired drying on the taste and aroma of Lu’an Guapian tea using metabolomics and sensory histology techniques

Lu’an Guapian (LAGP) tea, a representative Chinese roasted green tea, undergoes significant changes in taste and aroma during over-fired drying. However, limited studies have been conducted on these effects. This study employed metabolomics and sensory histology techniques to analyze non-volatile and volatile compounds the second drying and pulley liquefied gas drying (PLD) samples. The results revealed that after PLD, the samples exhibited lower umami, bitterness, and astringency; whereas floral, sweet, roasted, cooked corn-like, and cooked chestnut-like aromas became stronger. Among them, the content of (−)-epigallocatechin gallate, glutamic acid, and theogallin, which were closely related to taste, decreased by 4.5 %, 12.3 %, and 10.4 %, respectively. Eight key aroma components were identified as the main contributors to the sample aroma changes: (E)-β-ionone, dimethyl sulfide, (E,E)-2,4-heptadienal, geraniol, linalool, benzeneacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, and hexanal. This study provides a theoretical basis for enhancing the quality of LAGP teas.

The use of non-invasive stool tests for verification of Helicobacter pylori eradication and clarithromycin resistance.

Clarithromycin resistance of Helicobacter pylori (H. pylori) represents a major challenge in eradication therapy. In this study, we assessed if non-invasive stool tests can be used to verify successful H. pylori eradication and determine clarithromycin resistance. In this prospective study, patients undergoing urea breath testing (UBT) for confirmation of H. pylori eradication were asked to collect the stool as both a dry fecal sample and fecal immunochemical test (FIT). Stool H. pylori antigen testing (SAT) was performed on these samples and assessed for its accuracy in eradication verification. Type and duration of antibiotic treatment were retrospectively collected from patient records and compared with clarithromycin resistance determined by PCR of stool samples. H. pylori eradication information was available for a total of 145 patients (42.7% male, median age: 51.2). Successful eradication was achieved in 68.1% of patients. SAT on FIT samples had similar accuracy for eradication assessment compared to dry fecal samples, 72.1% [95% CI 61.4-81.2] versus 72.2% [95% CI 60.9-81.7]. Clarithromycin resistance rate was 13.4%. H. pylori antigen testing on FIT stool samples to verify H. pylori eradication is feasible and has similar accuracy as H. pylori antigen testing on dry stool samples. Dry stool, but not FIT, was suitable for non-invasive identification of H. pylori clarithromycin resistance by rt-PCR personalizing antibiotic treatment strategies without the need for invasive diagnostics is desirable, as the cure rate of first-line empirical H. pylori treatment remains low.

Chitosan supported silver nanostructures as surface-enhanced Raman scattering sensor: Spectroscopic and density functional theory insights

In this work, nanostructures comprising silver nanoparticles supported on a wrinkled chitosan matrix (Ag@Ch) were successfully synthesized by a simple aging process at room temperature for four days through self-assembly. Chitosan, a natural polysaccharide was used as a support as well as a reducing agent for the formation of Ag nanostructures and the creation of hotspots for SERS activity. The fabricated Ag@Ch nanostructures were characterized by several spectroscopic techniques and were used as a surface-enhanced Raman scattering (SERS) substrate. The effect of wet, dry, and liquid samples on the SERS enhancement has been studied and was found to be effective for sensing Methylene blue, Crystal Violet, and p-Nitrophenol with detection limits of 3.8, 8.1, and 8.2 ppb respectively. The SERS enhancement of the Ag@Ch was attributed to the combination of both electromagnetic (EM) and chemical effects (CE). Density functional theory (DFT) calculations were used to explain the observed surface enhancement. Good agreement was observed between the experimental and simulated spectra.

Saw marks in bone: A preliminary empirical study to inform decision making and best practice

Forensic toolmark examiners compare marks between those observed on an item/surface and those made by a reference implement, such as a particular tool or weapon, to provide an opinion of the likelihood of common origin. It is widely accepted that such comparison opinions need to be underpinned by empirical research, and this study aimed to add to the knowledge base relied upon when developing and comparing saw marks in bone, a substrate encountered in body dismemberment cases. Porcine bones were used as a human proxy; they were either fresh with residual soft tissue and bodily fluids present (‘wet’) to replicate dismembered bones shortly post-mortem, or processed to remove soft tissue and moisture content (‘dry’) to represent cases of dismemberment after an extended period of decomposition and exposure. The bones were cut using one implement of each of five classes: hand saw, mitre saw, reciprocating saw, oscillating saw, and serrated knife. They were cut, either completely through (except for serrated knife), giving two surfaces per cut to examine, or to a depth up to 3 mm (false starts). Five replicates per combination of bone condition, saw, and cut type gave 130 bone samples. These were then cleaned and cast using Isomark Silicone Polymer Compound or Mikrosil, giving 260 cast samples. All bone and cast samples were photographed, examined for various class characteristic markers, and specific markers measured. No significant differences between Isomark and Mikrosil casts were observed when compared side-by-side, demonstrating suitability of both materials for casting of saw marks on bone. Although saw marks presented more class characteristic markers on dry than wet bones, calculations of tooth distances and measurements of kerf width (KW) from marks did not significantly differ between bone conditions, with exception of the reciprocating saw that produced false start marks with significantly larger minimum KW on wet than dry samples. Further analysis supported that tooth distances on marks made by hand and oscillating saws are sufficiently accurate for the determination of saw teeth per inch (TPI). However, one tooth distance on marks made by reciprocating saws did not accurately represent TPI. Finally, examination of presence or absence of class characteristic markers on each saw mark demonstrated consistent variation between saw classes. These results enabled the development of exclusion-based decision trees, and a reference database (available on request), for use by toolmark examiners in their evaluation of saw types based on class characteristic markers observed in cut bone.

The impact of supercritical CO2 exposure time on the effective stress law for permeability in shale

Carbon dioxide (CO2) sequestration in shale formations is regarded as an effective approach for reducing CO2 emissions. Permeability is critical for CO2 geological sequestration as it impacts migration of CO2 in shale formations. The effective stress coefficient for permeability (χ) scales the relative influence of pore pressure on permeability compared to confining pressure. This study examined the changes in χ of dry and wet shale samples with different times of supercritical CO2 (ScCO2) exposure. The results suggest that, as ScCO2 exposure time increases from 0 to 40 days, the χ of dry shale increases from 0.8304 to 0.9563, and that of wet shale increases from 0.8379 to 1.0134. Wet shale exhibits a greater increase in χ than dry shale for the same exposure time. These changes in χ may result from CO2-shale interaction that converts smaller-sized pores in shale into larger-sized pores, based on nuclear magnetic resonance (NMR) measurements. Furthermore, the presence of water intensifies the response of shale to ScCO2, thereby enhancing this transformation. Our findings provide insights into the accurate prediction of shale permeability evolution during CO2 storage, and can assist in optimizing CO2 injection strategies as well as evaluating the potential for CO2 sequestration.

An exploratory investigation into moisture content and wind impact on the fire behaviour of modular living walls

Vertical greenery systems (VGS) consist of vegetation biomass and organic materials as well as plastics or metal elements in supporting systems. In this work, we investigate fire properties of live and dead plants as part of complete VGS systems (living walls, LW). Small-scale tests using a cone calorimeter and medium-scale tests using the SBI method were used to determine reaction to fire properties. Full-scale experiments were carried out to approximate the flame spread with and without wind along a living wall. Highly moist plants lead to slower spread of the fire, but have not prevented spreading the fire on the plastic potting, which in all cases was eventually involved in the fire and burned down to a collapse. On dry vegetation and without wind, the vertical flame spread velocity was up to 90 cm/s, and horizontal up to 2.7 cm/s. Wind conditions have changed the living wall fire performance, accelerating the fire spread on the vegetation and the fire of plastic potting as well. For moist samples in PN-B 02867 test the test duration (until full destruction of the facade) was 2100 s without and 1150 s with wind. For dry samples, this was 1350 s and 590 s, respectively.

Preparation and Characterization of Nano-waste glass powder

This experimental study investigates top-down grinding to turn used waste glass into nano-glass powder. The study explores a new instrument locally manufactured to synthesize nano-glass powder. The high-energy ball mill was manufactured based on design, material, assembly, testing, optimization, and quality control. Two milling environments were examined: wet with water as a surfactant liquid and dry with varying grinding times. In addition, this study compared the output of nano glass created from mechanical and chemical grinding processes. Blaine's method for surface area measurement results of nanoscale powder samples produced by the wet grinding method showed a steady increase commensurate with the grinding duration, as the 12-h grinding specimen was the highest in surface area. In contrast, dry grinding samples showed anomalies in some instances due to the agglomerate phenomenon, such as 8- and 10-h grinding samples. Moreover, FE-SEM showed that the 12-h grinding specimen has the smallest particle size. But the AFM illustrated accurately with the 2D measurement that these particles have cortical shapes, which may describe the secret beyond the high surface area. X-ray diffraction (XRD) and AFM tests showed that in the case of nanoscale glass particles, regardless of their morphology status, the shape of the particle itself is the deciding factor in giving the Nano powder the highest particle surface area. The specimen milled with 4 h of dry grinding is best suited for civil engineering research applications, while other applications that need a small amount of nano glass are recommended to use chemical methods despite their dangerous processes.