Threshold Limit Research Articles

Body mass index and age at menarche as predictors of adverse reproductive outcomes

Introduction. The continuum and pregnancy outcomes in adolescent girls and women of reproductive age, differences between them are partly predetermined by pregestational factors, in particular body mass characteristics. Today, the key role is assigned to the age at menarche, which indicates the achievement of mature reproductive function.Aim. To identify and compare the relationship between the age at menarche combined with the pregestational body mass index (BMI) and the adverse reproductive outcome (ARO) variant in women of reproductive age and adolescent girls.Materials and methods. At total of 967 women with ARO were enrolled in the prospective cohort multicenter study. The patients were divided into cohorts based on their age groups (adolescent girls (n = 182) or women of reproductive age (n = 785)) and the ARO variants. Four groups of women were identified: women with non-developing pregnancy (NDP) (n = 244), women with extra-uterine pregnancy (EP) (n = 115), women with spontaneous miscarriage (SM) (n = 299), and women with preterm birth (PB) (n = 309).Results and discussion. It was found that a later ARO corresponds to a higher BMI: a more probable BMI for SM is over 23, for NDP is 23 and less; for PB is over 25, for SM is 25 and less. No threshold BMI limit distinguishing between EP and NDP was identified. The BMI for adolescent girls is generally significantly lower than the BMI for women of reproductive age; it is significantly higher in EP as compared with women of reproductive age and comparable in SM. A trend towards a higher BMI in SM compared to NDP both in women of reproductive age with BMI over 24 and in adolescent girls with BMI over 20 but with different threshold limits is shown. The threshold BMI limit distinguishing PB from SM in reproductive age is 25 and higher, and in adolescent girls it does not reach 23.Conclusion. In clinical practice, it is recommended to use navigators for predicting ARO variants based on pregestational BMI and/or age at menarche, taking into account the age group of patients, which are obtained using classification trees.

The grey zone of taxonomy—The case of the Sikkim Myotis (Chiroptera: Vespertilionidae: Myotis sicarius), first recorded from Southeast Asia

Abstract In taxonomic works, the weight to be given to morphological, mitochondrial, or nuclear signals, and the assessment of differences as species or subspecies distinctions has also varied considerably over the past decades and is largely a subjective research decision. This apparent example of the “grey zone of taxonomy” underpins the need of critical studies of as many specimens as possible and of using both mitochondrial and nuclear genes in taxonomic-systematic studies, as phylogeny based on uniparentally inherited genes alone may not represent true evolutionary scenarios. Myotis sicarius, a species occurring thorough the Himalayan foothills was found for the first time out of South Asia, in North Vietnam. Analysis of topotypical and Vietnamese specimens revealed high mitochondrial heterogeneity – at the upper limit of the usual threshold of intraspecific difference – but only minute nuclear sequence and negligible morphological differences. Albeit the large geographic distance between the two records might suggest the existence of two putative reproductively isolated taxonomic units, based on the incongruent results we concluded that the split of geographic populations of M. sicarius into different taxa is unsupported. As a morphologically closely resembling species, we also reviewed the taxonomic status of the two morphological forms of M. annectans and synonymizing M. primula with M. annectans was also corroborated by our phylogenetic analyses.

Influence of statistical methods on lower limits of dose estimation in biological dosimetry

Purpose In cases of radiological or nuclear events, biological dosimetry enables decisions whether an individual was exposed to ionizing radiation and the estimation of the dose. Several statistical methods are used to assess uncertainties. The stringency of the applied method has an impact on the lowest dose that can be detected. To obtain reliable and comparable results, it is crucial to harmonize the applied statistical methods. Materials and methods The decision threshold and detection limit of the statistical methods were derived for variable cell numbers. The coverage of the 95% confidence intervals as well as the false-positive and false-negative rates of the methods were compared based on simulations. The evaluated methods included a graphical method, the propagation of errors and a Bayesian method. Results The minimum resolvable doses, the doses at the detection limit and the coverage were relatively variable between the compared methods. The Bayesian method showed the best coverage, lowest resolvable doses and had false-positive rates close to 5%. The graphical method with the combination of two 83% confidence intervals also showed promising results. The other methods were either too conservative or underestimated the uncertainties for some doses or cell numbers. Conclusions The assessment of the lower dose limits is a central part of biological dosimetry and the applied statistical methods have a strong influence on the interpretation of the results. Simulations enable comparisons between methods and provide important information for the harmonization and standardization of the uncertainty assessment.

Nutritional Risks of Heavy Metals in the Human Diet—Multi-Elemental Analysis of Energy Drinks

Background: In recent years, the consumption of energy drinks (EDs) by adolescents and young adults has increased significantly, so concerns have been raised about the potential health risks associated with excessive ED consumption. Most analyses on EDs focus on the caffeine content. Research on the content of minerals (essential and toxic) in energy drinks can be considered scarce. Therefore, there is a need for research stating the actual status of heavy metal content in commercially available energy drinks. Methods: This research presents the determination of the total concentrations of macro-elements and trace elements (TEs), such as Na, K, Mg, Ca, Al, Cr, Co, Cu, Fe, Mn, Ni, B, Zn, V, Sr, Ba, Pb, Cd, and As in nine samples of energy drinks using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) techniques. Results: The order in the content of macro-minerals in the EDs was as follows: Na > K > Mg > Ca. The results showed that ED 1, ED 3, and ED 7 samples had the highest micro-mineral concentrations. All the samples had a hazard quotient and hazard index < 1, indicating no non-carcinogenic risk from exposure to single or multiple heavy metals in both the adolescent and adult age groups. Some samples exceeded the threshold limit of acceptable cancer risk for As, Ni, and Cr in both adolescents and adults. Conclusions: This assessment showed that in addition to health implications based on the caffeine content of EDs, there might be a carcinogenic risk associated with the toxic element content of these beverages. This research also highlights notable differences in the TE levels among various ED brands, which may have important implications for consumer well-being and health.

Modelling resilience dynamics for smart manufacturing systems: quantification and empirical analysis

ABSTRACT Smart manufacturing contributes to a better management of uncertainties and risks in today’s business environment, leading to a more resilient system. Despite its significance, the quantification of resilience in manufacturing environments is not well developed and is considered a pressing research gap. This study introduces a novel approach for assessing resilience through the development of a mathematical model for smart manufacturing systems. The sensitivity and applicability of the proposed model are investigated through simulation-based experimentation. The results demonstrate the level of resilience with the adaptability of smart manufacturing technologies. Interestingly, the trigger point derived from the simulation results is an indicator of the threshold limit for effective implementation of smart manufacturing technologies for the desired system resilience. The research provides a tool for decision-makers in industry that are considering investing in smart manufacturing solutions to increase their operational resilience. Decision-makers can design the deployment of smart manufacturing systems based on an informative trade-off to maintain the required resilience capabilities and achieve a competitive edge in the market.

Heavy Metal Deposits in Toilet Tissues Sold in Markets within Enugu Metropolis, Enugu State

Studies were carried out to assess the deposits of selected heavy metals (Pb and Cd) in toilet tissues sold in markets within the Enugu metropolis, Enugu State using standard analytical procedures and instrumentation. The samples underwent digestion and were subsequently analyzed for heavy metals using an atomic absorption spectrophotometer. Toilet tissue samples A, B, C, and D had mean Pb values of 0.121±0.071, 0.258±0.040, 0.205±0.076, and 0.302±0.014 µg/g respectively. The mean Cd levels in the toilet tissue samples A, B, C, and D were 0.062±0.022, 0.037±0.008, 0.097±0.005, and 0.012±0.002µg/g respectively. The mean values of the investigated heavy metals were statistically significant in the studied toilet tissue samples. The toilet tissue samples, whether of high quality or low quality, poorly packaged or well packaged, had mean values of the studied metals within the recommended threshold limits.

Assessing the drought-tolerance and growth-promoting potential of strawberry (Fragaria × ananassa Duch.) rhizobacteria for consortium bioformulation

Plant growth-promoting rhizobacteria (PGPR) are known to influence plant root cells to regulate and induce specific traits related to growth promotion and survival. In the present study, rhizobacteria from strawberry plants were screened for stress tolerance under osmotic stress in TSB-mediated PEG 6000 (-0.73 MPa) and tested their ability to produce proline, exopolysaccharide, and free amino acids, all of which induce and regulate stress tolerance. The rhizobacteria were also distinguished for the production of 1-aminocyclopropane-1-carboxylate deaminase (ACCd) for the mitigation of drought stress. Among the 111 rhizobacterial isolates, 41 isolates grow above threshold limit in osmotic stress tolerance, 33 of which exhibited stress tolerance. Further characterization screened 27 isolates as capable growth promoters. Among the experimentally screened rhizobacteria, the isolates SBU4 and SDK8 [Pseudomonas fluorescens (OP627557) (PGPR1) and Pseudomonas glycinae (OP627558) (PGPR2)] exhibited the most promising phyto-beneficial potential. Both the isolates grew exponentially well during the log phase, with increased growth in Log CFU ml-1 under experimentally produced osmotic stress. The drought stress tolerance test results of the SBU4 and SDK8 isolates revealed the presence of proline (1.93 μg mL-1, 2.05 μg mL-1), exopolysaccharide (2.19 mg mg-1 protein, 2.58 mg mg-1 protein), and free amino acid (11.47 μmol g-1, 13.32 μmol g-1) and positive growth in ACCd-enriched DF media, an ACCd assay (α-ketobutyrate (0.56 μmol/ml, 0.64 μmol/ml) and ammonia (0.37 μg mL-1, 0.53 μg mL-1)). The isolates SBU4 and SDK8 performed well in qualitative tests for P solubilization, N fixing ability, siderophore chelation, HCN, and ammonia production, as well as in assays involving P producers (94.57 μg mL-1 and 92.86 μg mL-1), siderophore units (52.14% SU and 63.12% SU), and IAA producers (74.63 μg mL-1 and 72.64 μg mL-1). These rhizobacterial isolates were optimized under various growth factors (pH, temperature, incubation) to achieve a relatively high log CFU ml-1. The isolates achieved maximum Log CFU mL-1 when cultured in either a specific range of pH or temperature or growth period (incubation) under standard test conditions. The growth of cultures on cross-streaked nutrient agar plates was tested for an efficient, effective consortium bioformulation that enhances growth and specific traits (drought stress mitigation) in strawberry plants.

Investigating the thermal performance of a pipe-encapsulated movable PCM wall and its impact on reducing indoor heat gain during summer

The utilization of phase change materials (PCM) in building envelopes is considered to be an effective technology for reducing energy consumption during building operations. In this study, a novel approach is presented for integrating PCM into walls by encapsulating it using pipes, allowing for its mobility through the use of compressed air. Four experimentally validated thermal models, pipe-encapsulated movable PCM (PEM-PCM) wall (Model 1), wall with PCM fixed to the exterior (Model 2), wall with PCM fixed to the interior (Model 3), and wall without PCM (Model 4), were proposed to compare their energy efficiency in summer. Different upper threshold limits (Ttr,up) and lower threshold limits (Ttr,low) were employed to explore the impact of various threshold combinations control strategies on the thermal performance of the wall. The results show that the most effective operating scheme is Ttr,up of 27 °C and Ttr,low of 25 °C. In terms of long-term operation, cumulative summer indoor heat gain of Model 1 is 10.65 %, 10.85 % and 11.4% lower than that of Model 2,3 and 4. Notably, September demonstrates the greatest potential for energy savings, with Model 1 reducing the monthly cumulative indoor heat gain by 54.12% compared to Model 4.

An Evaluation of Antarctic Ice Core Nitrate Records as a Proxy for Solar Activity

AbstractNitrate (NO3−) deposition in polar ice sheets archives valuable information on past solar activity. However, interpretation of Antarctic ice core NO3− records as a proxy for past solar activity remains challenging due to multiple sources and processes controlling NO3− variability in ice core records. Here, we present a new high‐resolution ice core NO3− record (1905–2005 CE) from coastal Dronning Maud Land, East Antarctica, to investigate the solar signal and other forcing factors/processes in controlling ice core NO3− variability. Our record exhibits significant periodicity in the range of 8–12 years frequency band during 1940–2005 CE, apparently identified as the signal of ∼11 year sunspot cycle; however, such signal was not detected in the previous interval during 1905–1940 CE. To address the discontinuous and/or obscured signals in the present ice core record and inconsistency among various Antarctica ice core records, we extended our investigations to 10 ice core NO3− records from various regions of Antarctica. Analysis of seven records for the common interval from 1738 to 1990 CE reveals dominant periodicities of 8–12 years, indicating solar forcing as a primary driver, followed by precipitation modulated by El Niño‐Southern Oscillation and Pacific Decadal Oscillation. Further, our investigation reveals that the solar signal extracted from multiple records becomes undetectable when mean annual hemispheric sunspot numbers larger than 140, suggesting this is a threshold limit for detecting the solar signal. These findings will improve our present understanding of ice core NO3− records as a proxy for past solar activity.

Mineralogy and geochemical characteristics of the Ibaga copper ore deposit in Singida-Tanzania: Implication for source of copper mineralization and ore quality

The Ibaga copper deposit in the Nzega-Sekenke terrane is hosted in meta-sedimentary rocks and it has been rudimentarily mined by small scale miners for more than a decade. To study mineralogy and geochemical characteristics of the deposit, samples from outcrops and mining pit were collected for XRD, XRF and ICP-MS analysis. Results show that the ore is composed of chalcopyrite, covellite, cuprite, malachite and azurite as ore minerals; whereas augite, chlorite, actinolite, greenalite, birnessite, quartz, magnetite, berlinite, cristobalite, hematite, calcite and parisite are gangue minerals. The deposit is characterized by Cu (3.2–31.3 wt %), Fe (2.1–25.1 wt %), Ag (0.6–16.6 wt %) and lower concentration of penalized impurities Sb, Bi, As, Cd and (Al2O3 + MgO) than threshold limit set by copper smelters and refineries. The ore shows significant variation of Y/Ho = 21.75–40.00, Zr/Hf = 23.33–58.61 and Nb/Ta = 4.20–27.17. Presence of higher REE values of up to 2000 ppm in sample BG04 due to REE minerals known as parisite indicates that the deposit is potential prospect for REE. Consistent with the granites, the ore has Sm/Nd < 0.24 and enriched in LREE relative to HREE where ∑LREE/∑HREE = 4.7–9.0 and La/Lu = 32–769.3. The scatter plot of δCe versus δEu for ore and rock samples suggests closer genetic relationship between the ore, granite and quartz-sericite-schist. These results imply that the granitic intrusion triggered mineralization by skarnification into meta-sedimentary rocks and subsequently the ore underwent supergene enrichment.

Assessment of Chemical Composition and Health Implications Associated with PM10 Exposure: A Comparative Study of an Urban Road Intersection and a Wood-Burning Vicinity

The chemical composition and potential health risks linked to human exposure to ambient PM10 particles were assessed at the Winneba highway intersection (WHI) and Apam, a wood-burning neighbourhood in Ghana’s Central Region. PM10 particulates were collected using a Gent sampler equipped with a Gast pump and a stacked filter unit. The sampling was done three times a week continuously from July 2022 to June 2023, for 24 h. A smoke stain reflectometer and an Ag-anode X-ray tube spectrometer were used to analyse the samples for black carbon and elemental contents, respectively. The health hazards associated with trace elements were evaluated using the US EPA health risk assessment model. The study’s findings indicated that the amounts of Cr (250.5 ng/m3) and Ni (358.1 ng/m3) detected at Apam surpassed the US EPA threshold limits, as did the values discovered at the WHI, which were 78.63 and 178.2 ng/m3, respectively. PCA indicated that PM10 particles were produced at WHI by soil dust, vehicle exhaust, brake and tyre wear, and two-stroke engines, whereas biomass burning, soil dust, and vehicle exhaust emissions contributed to PM10 at Apam. The non-carcinogenic risks of children’s exposure to trace metals in PM10 via the three exposure pathways were higher compared to adults. The overall cancer risk values for exposure to carcinogenic trace metals from ingestion and dermal contact were more than 10−4, suggesting high cancer risks: 9.49 × 10−4–5.20 × 10−3 for children and 9.03 × 10−4–5.26 × 10−3 for adults. Reducing PM10 and the health concerns it poses requires the use of clean fuel and the adoption of environmentally friendly transportation.

Engineered PVA-tamarind gum-based biocomposite for sustained ophthalmic delivery of moxifloxacin: Effect of nanocellulose on physicochemical, mechanoelectrical and permeation kinetics

Widely used polysaccharide-based films in ophthalmic drug delivery have major limitations of inadequate mechanical strength, poor electrical conductivity, and insufficient ocular drug permeability. Moxifloxacin (MFX) biocomposite film of adequate mechanoelectrical properties was developed for sustained ophthalmic drug delivery. Nanocellulose (NC) incorporated (2.5, 5.0, 7.5, and 10.0 %) PVA-tamarind gum-based moxifloxacin composite was prepared using solvent casting method. The addition of NC improved the mechanical properties of the film, demonstrating its ability to strengthen the structure. Stress relaxation (SR) of the film has been augmented (64.67±7.55 to 73.15±0.34 %) due to increased content of NC (0 to 10 %) respectively. Film containing 5 % NC showed the critical edge of tensile strength (11.9±0.39 MPa), and also the threshold limit of electrical conductivity (4.5*107 Ω). The same film exhibited continued drug release as well as erosion-controlled sustained ocular permeation (pH 7.4) and revealed the highest antibacterial activity (ZOI of disc diffusion, cm) with Pseudomonas aeruginosa (4.63±0.15) and Staphylococcus aureus (4.30±0.26) of MFX (≈224 μg). Notably, incorporating NC produced non-irritating and safe for corneal delivery as confirmed by the Draize model test. Our findings suggested that the NC-containing PVA-tamarind gum-based composite film holds a promising approach for sustained ophthalmic delivery of MFX.

A Reflective Thematic Analysis Into the Perceptions of Pregnant Radiographers Regarding the Usefulness of the PregiDose Mobile App to Enhance Fetal Dosimetry and Well-Being: Qualitative Exploration.

Pregnancy apps are widely used by pregnant women, who benefit from self-tracking features to support their health goals. Pregnant radiographers are considered a high-risk group of health workers practicing in ionizing radiation environments. Radiation exposure above threshold limits can cause harmful genetic effects on a fetus. Accordingly, pregnant radiographers are required to wear special fetal dosimeters, which provide real-time readings of radiation dose exposure to the fetus. Pregnant radiographers have the responsibility to self-track their fetal doses to ensure that the threshold limit of 1 mGy is not exceeded. The traditional method used to track doses includes a written log of doses in a notebook. Thus, PregiDose, a unique offering in the context of pregnancy apps, was developed to enhance fetal dose tracking and monitoring using technological methods. This study aims to describe the users' perceptions of the app's usefulness using PregiDose in a natural setting. The overarching framework adopted for the study was a design science research (DSR) methodology encompassing five steps, namely (1) problem awareness, (2) suggestion, (3) development, (4) evaluation, and (5) conclusion. This paper presents the evaluation step of DSR. DSR step 4 included a qualitative approach to explore users' perceptions regarding the app. Data were collected using a semistructured interview guide. Open-ended questions were guided by the app's core features, namely dose tracking, education, and wellness. In total, 17 pregnant radiographers in South Africa enrolled to use the app, 9 (53%) engaged with the app, and 4 (24%) agreed to participate in the feedback interviews. The data were collected from October 2023 to March 2024 and analyzed using a reflective thematic data analysis method. Three overarching themes emerged from the data, namely (1) usefulness of PregiDose, (2) barriers to PregiDose adoption and use, and (3) recommendations for the advancement of PregiDose. Users labeled the app's usefulness as positive and perceived it as a modern approach to traditional dose-tracking methods. They perceived the graph output of the dose-tracking feature to be useful for viewing their accumulative doses. They did not fully engage with the journaling feature, indicating that it was a personal preference and not a practice they would usually engage in. Physiological barriers, such as fatigue and "pregnancy brain," were contributors to decreased engagement. Finally, because of the demanding workload and fast-paced nature of the radiography department, users recommended the automation of fetal dosimetry through the Internet of Things. PregiDose is an occupational health and safety mobile app developed for pregnant radiographers through a DSR approach. The app offers a modern method of dose tracking consistent with technological advancements in the context of self-tracking. However, future implementation would require using Internet of Things to make fetal dose tracking more effective.

Levels of mandatory CSR compliance and the payoff: evidence from India

Purpose This paper aims to examine the diverse levels of corporate social responsibility (CSR) expenditure among Indian companies and its influence on their performance. The study aims to determine whether exceeding the mandatory CSR spending limit provides an edge to companies that outperform in enhancing corporate firm value. Design/methodology/approach A dynamic model using system generalized method of moments (GMM) was used to analyze a balanced panel data set of 191 firms over seven years, spanning from 2016 to 2022. Return on assets was used as a proxy to gauge financial performance. At the same time, the study also examined the robustness of the results by considering return on equity and Tobin’s Q as additional measures. Findings The study results indicate that, in a mandatory CSR setting, all companies are generally perceived as performing and reporting on CSR equally. Hence, it will not make any payoff, although few companies outperform. Therefore, companies should differentiate themselves regarding CSR spending and reporting to claim a competitive advantage in the market. The study also suggests that the payoff of mandatory CSR expenditure for both performing and outperforming companies is reflected more in non-quantifiable firm characteristics than in measurable performance metrics. Research limitations/implications The period of study covers 7 years, i.e. 2015–2016 to 2022–2023. This may limit capturing long-term CSR practices and firm performance trends. Additionally, data from only 191 Indian companies restrict generalizability; future research should include diverse geographic regions with mandated CSR spending to provide a more comprehensive view. In subsequent studies, contextual factors like regulatory changes and macroeconomic conditions could be considered moderating variables. Practical implications The study provides valuable insights to top management, indicating that spending beyond the threshold limit of mandatory CSR spending does not enhance corporate firm value. Instead, this additional investment may yield benefits in the form of goodwill and reputation over the long term. Social implications This study assists corporations in optimizing their CSR strategies to enhance their social and financial performance impact. Moreover, the study suggests ways to improve the CSR payoff and the need for increasing stakeholder satisfaction. Originality/value The study provides original insights into the relationship between mandatory CSR spending and firm performance in the Indian context, revealing that CSR spending does not significantly impact financial metrics, and it highlights the importance of considering a non-quantitative matrix to enhance the firm value in a mandatory CSR setting.

Total mercury exposure through canned tuna in water sold in Quito, Ecuador

Mercury is a toxic trace metal found in seafood products owing to its bioaccumulative and ubiquitous nature. Seafood and fish are frequently consumed, being necessary to assess its human health risk. Accordingly, this study quantified total mercury in samples of canned tuna in water from supermarkets in the Metropolitan District of Quito in Ecuador, in order to ensure that Hg content is within the maximum limits stablished in national and international regulations. Total mercury levels were measured through cold vapor atomic fluorescence spectrophotometry. Three of the most consumed tuna brands in Ecuador were analyzed, coded as A, B, and C, according to the price at which they are sold in the market (A < B < C). Results indicated that mean total mercury in different tuna brands were within the permissible limits. Total mercury concentrations were 0.14 ± 0.11 mg kg−1; 0.41 ± 0.42 mg kg−1; and 0.25 ± 0.22 mg kg−1 for brands A, B, and C, respectively. However, for brand B the potential non-carcinogenic risk of mercury for consumers exceeded the threshold limit (> 1). When considering the highest total mercury content to which Ecuadorian population is exposed through the consumption of brand A, B, and C, the recommended weekly intake for children and adults were: A: 63 g and 306 g; B: 12 g and 57 g; C: 30 g and 144 g, respectively.

Work-Function-Dependent Reduction of Transition Metal Nitrides in Hydrogen Environments.

Amidst the growing importance of hydrogen in a sustainable future, it is crucial to develop coatings that can protect hydrogen-sensitive system components in reactive hydrogen environments. However, the prediction of the chemical stability of materials in hydrogen is not fully understood. In this study, we show that the work function is a key parameter determining the reducibility (i.e., denitridation) of transition metal nitrides (TMNs) in hydrogen radicals (H*) at elevated temperatures. We demonstrate that, when the work function of a TMN system drops below a threshold limit (ϕTH), its reduction effectively stops. We propose that this is due to the preferential binding of H* to transition metal (TM) atoms rather than N atoms, which makes the formation of volatile species (NHx) unfavorable. This finding provides a novel perspective for comprehending the interaction of hydrogen with TM compounds and allows prediction of the chemical stability of hydrogen-protective coatings.

Sand Detection Using Acoustic Sand Monitors for Liquid-Dominated Multiphase Flow Production

Summary Solid particle erosion in the oil and natural gas industry can be damaging to pipe fittings and equipment, which can lead to maintenance or, in the worst case, a production shutdown. In both cases, this represents a huge economic loss for industry. Acoustic sand monitoring is one of the most widely used practices to provide an alarm and/or estimate the amount of sand entrained in the flow. In addition to being commercially available, they can be easily clamped to the outside of a pipe wall, measuring the acoustic energy generated by sand grain impacts on the inner side of a pipe wall. In this work, a broad range of multiphase operating conditions has been experimentally investigated with acoustic sand monitors in large-scale flow loop facilities to determine the effectiveness of sand monitoring in liquid-dominated multiphase flow. The main objective is to use acoustic sand monitors to determine the threshold sand rate (TSR). This is the minimum sand rate necessary to achieve monitor output higher than the background noise (BN) level. Acoustic monitors were placed upstream and downstream of standard (r/D = 1.5) elbows while varying superficial gas and liquid velocities, sand sizes (25 μm, 75 μm, 150 μm, 300 μm, and 600 μm), and pipe diameters (2 in. and 3 in.) in the vertical orientation. The experimental conditions were selected to cover slug-churn, dispersed-bubble flow, and liquid-sand flow conditions. These results are compared with the previously obtained test results on 50.8-mm (2-in.) internal diameter (ID) test loops. In the 50.8-mm (2-in.) loop, threshold limits were observed for dispersed-bubble flow regimes and liquid-sand as compared with gas-dominated flow conditions. While TSR is the highest in dispersed-bubble flow regimes, the present data were compared with previous results obtained for annular, slug, and stratified flow patterns (FPs) in vertical flow. It was observed that the annular flow regime has the lowest TSR values, showing an increase in TSR when the liquid rate increased. The results from this work can help operators understand how acoustic monitors can detect and distinguish sand impact noise from the background flow noise in liquid-dominated multiphase flow in production facilities. In this way, greater assurance is provided to operators for optimizing oil and gas production rates, especially in wells that tend to produce solids.

Carving a niche in building energy using modern vernacular house with passive wall materials - A multi-criteria decision-making framework

The building sector, one of the world's largest energy consumers, includes vernacular houses that offer good living conditions. However, increasing population and energy demands have caused vernacular houses to impact the ecosystem negatively, thus losing popularity. Passive design features can alleviate this problem but entail several factors and alternatives. This study aims to develop a fuzzy-based multi-criteria decision-making framework for selecting an optimal wall material for vernacular house that satisfies the technical, economic, environmental and social factors. Seven different wall materials, along with governing factors like room temperature, humidity, cooling and heating loads, cost, comfort index, CO2 emission, job creation and social acceptability, are considered. Four fuzzy-based decision-making tools are used, followed by sensitivity analysis to examine the results. A test cell of an established 3BHK vernacular house is made using design-builder and is simulated with Energy plus software. The error indices confirmed the design-builder model's accuracy, with NMBE and CV-RMSE values for room temperature and relative humidity both under 1 %, well within ASHRAE 14's threshold limits. From the results, cinder concrete is found as optimal passive wall material, resulting in lower cooling and heating loads and CO2 emission by 0.68 %, 9.64 %, and 2.27 %, respectively, than traditional vernacular house.

Fabrication of FeCu/CC Composite for Efficient Removal of Nitrate for Aqueous Solution Via Electrochemical Reduction Process

AbstractThe electrochemical nitrate reduction (ENR) for the conversion of nitrate to nitrogen gas is a significant strategy to remediate the eutrophication in surface water. However, the exploitations and practical applications of suitable electrocatalysts still face great challenges. In this study, FeCu bimetal microparticles were deposited onto surface of carbon cloth (CC) to fabricate the FeCu/CC electrocatalyst for the removal of nitrate. Among obtained catalysts, the sample with Fe/Cu molar ratio of 1 : 15 (Fe1Cu15/CC) exhibits the excellent electroreduction efficiency for nitrate removal (R(NO3−), &gt;90 %) but an ineffective selectivity of N2 formation (S(N2), ~23 %). After the anchor of reduced graphite oxide (rGO) to surface of Fe1Cu15/CC, at the optimized condition without the assistance of chlorine oxidation, R(NO3−) and S(N2) of rGO/Fe1Cu15/CC catalyst reach 94.2 % and 72.8 %. After 5 day endurance test, the values of R(NO3−) and S(N2) are still 82.9 % and 62.8 %, demonstrating the promising durability of this catalyst electrode. Meanwhile, the potential application of rGO/Fe1Cu15/CC was explored for the treatment of simulated wastewater discharged by urban wastewater treatment plant, the concentration of total nitrogen (TN) decreases from 15–1.17 mg/L, and this value is lower than TN threshold limit in Class IV of Chinese surface water quality standard.

Anaerobic digestion of dairy cow and goat manure: Comparative assessment of biodegradability and greenhouse gas mitigation

This study evaluated the anaerobic digestion (AD) of dairy cow and goat manure from dairy farming operations. The physicochemical characteristics, biodegradability and greenhouse gas emissions (GHG) reduction potential were assessed. Dairy goat manure exhibited higher volatile solids (16 % vs. 10 %) and 34 % greater chemical oxygen demand content (COD) compared to cow manure, indicating better suitability for AD. However, biochemical methane potential tests revealed higher methane yields from cow manure (81 % biodegradability) compared to goat manure (26 % biodegradability), attributed to slower hydrolysis rates and recalcitrant composition of goat manure. Both manures displayed suboptimal carbon-to-nitrogen ratios (<20:1) and excessive levels of mineral nutrients such as calcium. The ammonia–nitrogen and volatile fatty acid levels remained below threshold limits throughout the anaerobic digestion process, indicating no significant accumulation or inhibition. Recovering biogas through AD showed potential GHG reductions of 64 % (2.21 t CO2-eq/cow·year) and 69 % (0.27 t CO2-eq/goat·year) compared to conventional manure management practices. While pretreatment and co-digestion could enhance biogas production, further research is needed to optimise these strategies for efficient resource recovery and environmental sustainability in dairy farming operations.Abbreviations: AD, anaerobic digestion; AWMS, animal waste management systems; BMP, biochemical methane potential; CHNS, carbon, hydrogen, nitrogen, and sulphur; C/N, carbon-to-nitrogen, COD, chemical oxygen demand; GC-FID, gas chromatography-flame ionisation detection; GHG, greenhouse gas; GWPM, global warming potential of methane; He, helium; ICP-MS, inductively coupled plasma mass spectrometry; I/S, inoculum-to-substrate ratio; IPCC, International Panel on Climate Change; NH3-N, ammonia–nitrogen; SD, standard deviation; TBMP, theoretical biochemical methane potential; TN, total nitrogen; TS, total solids; VFAs, volatile fatty acids; VS, volatile solids.