Variable Composition Research Articles

Machine learning-based tropospheric delay prediction for real-time precise point positioning under extreme weather conditions

Satellite signals from the Global Navigation Satellite System (GNSS) are refracted as they pass through the troposphere, owing to the variable density and composition of the atmosphere, causing tropospheric delay. Typically, tropospheric delay is treated as an unknown parameter in GNSS data processing. Given the growing need for real-time GNSS applications, accurate tropospheric delay predictions are crucial to improve Precise Point Positioning (PPP). In this paper, time-series of tomography data are used for wet refractivity prediction employing Machine Learning (ML) techniques in both Poland and California, under extreme weather conditions including sweeping rain bands and storms. The predicted wet refractivity is implemented for tropospheric delay determination through ray-tracing technique. PPP processing is conducted in both static and kinematic modes using different setups. These are: (1) common PPP, called Com-PPP, (2) Ray-PPP, which applies obtained tropospheric delay on GNSS observations and thus eliminates tropospheric parameters from unknowns, and (3) Dif-PPP, which applies the difference of estimated tropospheric delay from ray-tracing and GNSS measurements to compensate for the remaining tropospheric delay in the observations. The results show that Dif-PPP reduces the Mean Absolute Error (MAE) of the Three-Dimensional (3-D) component between 8 and 33% in static mode compared to the Com-PPP method. Additionally, it can improve the convergence time of the up component in the kinematic mode by between 6 and 17%.

Triassic–Jurassic alkaline magmatism in the Ivrea-Verbano Zone, Southern Alps: A zircon perspective on mantle sources and geodynamic significance

The Ivrea-Verbano Zone (IVZ; western Southern Alps) consists of a distinctive sequence of the lower continental crust of the Adriatic plate, extending down to the subcontinental lithospheric mantle. It is characterized by a large variety of intrusive bodies of variable geochemical composition and age, offering a unique insight into the evolution of mantle-derived magmatism in post-collisional and extensional geodynamic settings. In this study, we characterize a suite of alkaline dykes intruding a mantle massif – the Finero Phlogopite Peridotite in northern IVZ. These dykes include zircon-bearing diorites and anorthosites, mainly composed by HFSE-rich amphibole and phlogopite, albite (>90 vol% in anorthosites) and apatite. Zircon, monazite, ilmenite, titanite, Nb-rich oxides, and carbonates are common accessory minerals. Additionally, a “composite” diorite dyke containing both HFSE-rich and HFSE-poor amphiboles was investigated. The study is aimed at providing new trace element, UPb geochronological and LuHf isotopes dataset on zircon from these alkaline dykes, to refine the understanding of their mantle source characteristics, emplacement age and geodynamic implications. The trace element composition of zircons from the studied dykes points to segregation from melts with alkaline to ultra-alkaline affinity. Concordia UPb ages of zircon from the alkaline diorite dykes span from 221 to 191 Ma, which are interpreted as the result of multiple crystallization/recrystallization stages related to different magmatic pulses. Conversely, zircon from anorthosite and composite diorite dykes yield a narrow time range of 198–202 Ma, highlighting the occurrence of a magmatic pulse around ca. 200 Ma. The εHf(t) values (+13.4 to +5.7) of zircon from the alkaline diorite dykes are significantly more positive compared to the values in those from anorthosite and composite diorite dykes (+4.2 to −0.4), suggesting that the parental melts were derived from heterogeneous asthenospheric mantle sources with low to moderate amount of recycled continental crust components. Our data and reappraisal of the literature indicate that the IVZ experienced a protracted period of alkaline magmatism from ca. 235 Ma to 185 Ma. The melts migrated along mantle shear zones during the Triassic-Jurassic lithospheric extension. Different pulses of alkaline magmatism were associated with relevant extensional tectonic stages recorded by the continental crust, presumably triggering a passive uplift of heterogenous asthenospheric reservoirs over a front of at least 500 km. This tectono-magmatic cycle is a precursor to the focused rifting stage which caused the opening of the Jurassic Alpine Tethys, enhancing Pangea fragmentation.

Environmental Changes Recorded in Sedimentary Rocks in the Clay-Sulfate Transition Region in Gale Crater, Mars: Results From the Sample Analysis at Mars-Evolved Gas Analysis Instrument Onboard the Mars Science Laboratory Curiosity Rover.

The Curiosity rover explored the region between the orbitally defined phyllosilicate-bearing Glen Torridon trough and the overlying layered sulfate-bearing unit, called the "clay-sulfate transition region." Samples were drilled from the top of the fluviolacustrine Glasgow member of the Carolyn Shoemaker formation (CSf) to the eolian Contigo member of the Mirador formation (MIf) to assess in situ mineralogical changes with stratigraphic position. The Sample Analysis at Mars-Evolved Gas Analysis (SAM-EGA) instrument analyzed drilled samples within this region to constrain their volatile chemistry and mineralogy. Evolved H2O consistent with nontronite was present in samples drilled in the Glasgow and Mercou members of the CSf but was generally absent in stratigraphically higher samples. SO2 peaks consistent with Fe sulfate were detected in all samples, and SO2 evolutions consistent with Mg sulfate were observed in most samples. CO2 and CO evolutions were variable between samples and suggest contributions from adsorbed CO2, carbonates, simple organic salts, and instrument background. The lack of NO and O2 in the data suggest that oxychlorines and nitrates were absent or sparse, and evolved HCl was consistent with the presence of chlorides in all samples. The combined rover data sets suggest that sediments in the upper CSf and MIf may represent similar source material and were deposited in lacustrine and eolian environments, respectively. Rocks were subsequently altered in briny solutions with variable chemical compositions that resulted in the precipitation of sulfates, carbonates, and chlorides. The results suggest that the clay-sulfate transition records progressivelydrier surface depositional environments and saline diagenetic fluid, potentially impacting habitability.

Active aero-visco-elastic flutter control and layerwise modelling of supersonic smart sandwich panels with variable stiffness composites

Active aero-visco-elastic flutter control and layerwise modelling of supersonic smart sandwich panels with variable stiffness composites

Lithological Mapping of the Neoproterozoic Basement Rocks in the Area East El-Sibai Core Complex (SCC), Central Eastern Desert of Egypt, Based on Remote Sensing Data and Field Observations

Spectral data are an active tool for mineral exploration, lithological, and structural mapping by spectral classification; due to its accuracy, ease of use, and low cost, especially in inaccessible areas. This study aims to integrate Landsat-8/OLI and ASTER images with extensive field survey and petrographical analysis to discriminate the Neoproterozoic basement rock units in the area east Gabal El-Sibai. In image enhancement techniques, we used the Correlation Coefficient and Optimum Index Factor for choosing the best-colored images to discriminate various rock units based on spectral signature curves. The exposed rock units consist of granitic rocks of variable compositions intruded directly into ophiolitic and island arc associations. The different rock units and structural elements in this study were mapped and discriminated using False Color Composites images (7-6-1 of Landsat-8 and 9-4-3 of ASTER), Minimum Noise Fraction (6-5-1), Principal Component Analysis (4-1-2 for Landsat-8 and 3-1-4 for ASTER), two newly proposed ratios images (3/4, 6/7, 5/6 for Landsat-8 and 4/1, 3/1, 8/9 for ASTER), with the Maximum Likelihood Classification and Support Vector Machine Classification. In conclusion; the overall accuracy and the Kappa coefficient show a good agreement with the Principal Component Analysis and Band Ratio results in the current geological map. Therefore, the suggested methodology shows that optical data have a strong potential for discriminating between lithological units. This approach provides accurate information to geologists, geophysical engineers, and land-use land-cover decision-makers. It can also improve and enhance the accuracy of geological maps in the Nubian Shield in Egypt and other arid environments worldwide.

Heterogeneization of Biodiesel Production by Simultaneous Esterification and Transesterification of Oleins

The production of biodiesel via simultaneous esterification and transesterification reactions of residual fats such as palm oleins, with variable TG and FFA composition, using methanol and methane sulfonic acid (MSA) or an acid carbon-based structured catalyst (SO3H-C) as homogeneous and heterogeneous catalysts respectively, has been investigated. The influence of various parameters, such as methanol to oil molar ratio, operating temperature, amount of catalyst, or nature and composition of the raw materials on the fatty acid methyl esters (FAME) yield was studied. It was determined that increasing the methanol to oil molar ratio resulted in an increase in the conversion of TG and FFA and a higher FAME yield; besides, reaction temperature has a strong effect. The best conditions tested to obtain the highest FAME yield (99.2%) was a methanol to oil molar ratio of 12:1, 120 °C (12 bar), a reaction time of at least 1 h, and 3% MSA as a homogeneous catalyst. The work demonstrated that an acidic solid catalyst, SO3H-C, homemade prepared, could be used as a heterogeneous catalyst in the simultaneous process under the optimized reaction conditions, achieving a complete esterification conversion with some limitations with respect to the transesterification reaction and a FAME yield close to 90.5%.

Synthesis and catalytic study of manganese ferrites obtained by partial oxidation of ferrous hydroxide with permanganate

The main goal of present work was to show a new method of synthesis, of manganese ferrite (MnxFe3-xO4, x = 0.085 to x = 0.379) with variable composition of Fe(II), Fe(III) and Mn(II) ions by coprecipitation, with the application of KMnO4 and KNO3 as oxidizing agents, followed by the characterization and research of the catalytic properties of the prepared samples. The chemical analysis by Flame Atomic Absorption Spectroscopy (FAAS), X-Ray Fluorescence Spectroscopy (XRFS) and potentiometric titration, allows to calculate the elemental and ionic composition of the prepared ferrites. The use of KMnO4 enables not only the oxidation of iron(II) to iron(III) but also a source of manganese(II). The Mn substitution in MnxFe3-xO4 ferrite as well as higher gel dispersion, cause the exponential increase of the catalytic activity, which is more significant in smaller particles.

Temporal shift in groundwater fauna in southwestern Germany

Abstract. Groundwater is an important source of freshwater; drinking water; and service water for irrigation, industrial and geothermal uses. It is also the largest terrestrial freshwater biome in the world. In many areas, this habitat is naturally or anthropogenically threatened. This study uses long-term groundwater data from southwestern Germany to identify shifts in groundwater fauna due to natural or anthropogenic impacts. Comprehensive analysis of metazoan groundwater fauna and abiotic parameters from 16 monitoring wells over 2 decades revealed no overall temporal trends in faunal abundance or biodiversity (in terms of number of species) and no significant large-scale trends in abiotic parameters. While 9 wells out of 16 show stable ecological and hydrochemical conditions at a local level, the remaining wells exhibit shifting or fluctuating faunal parameters. At some locations, these temporal changes are linked to natural causes, such as decreasing dissolved oxygen contents or fluctuating temperatures. A multivariate PHATE (Potential of Heat-diffusion for Affinity-based Trajectory Embedding) analysis suggests that, beside the hydrogeological setting, varying contents of sediment and detritus impact faunal abundance. By examining aerial images of the surroundings of individual wells, we found that anthropogenic impacts, such as construction sites and surface sealing, can cause significant shifts in groundwater fauna and changes in the ecological status in positive as well as negative direction. However, variable faunal compositions and abundances were also observed for sites with very stable abiotic conditions in anthropogenically less affected areas such as the Black Forest. These findings indicate that hydro(geo)logical changes and surface conditions, such as land use, should be assessed in line with hydrochemical parameters to better understand changes in groundwater fauna. Accordingly, reference sites for natural conditions in ecological assessment and biomonitoring schemes for groundwater protection should be selected carefully.

Research Progress of High-entropy Oxides for Electrocatalytic Oxygen Evolution Reaction.

High-entropy oxides (HEOs), similar to high-entropy materials (HEMs), have "four-core effects", i. e., high-entropy effect, delayed diffusion effect, lattice distortion effect and cocktail effect, which have attracted more and more attention in the scientific field of renewable energy technology due to their unique structural characteristics, variable chemical composition and corresponding functional properties. HEOs have become potential candidates for electrocatalytic oxygen evolution reaction (OER), which is a key half reaction for electrolytic CO2, nitrogen reduction, and water electrolysis. However, the precise synthesis of HEOs with a wide range of components and structures is challenging, not to mention their active and stable operation for OER. In this paper, we review the recent advancements in the electrocatalytic oxygen evolution facilitated by HEOs in water electrolysis. We analyze these developments from the perspectives of activity and stability in acid and alkaline conditions, respectively. Furthermore, we summarize the design from the aspect of element composition, structure, morphology, and catalyst-support interactions, along with related reaction mechanism of HEOs. Additionally, we discuss the current challenges faced by HEOs in the field of OER and suggest potential directions for the future development of HEOs beyond water electrolysis application.

Subductability of continental lithosphere

Multiple lines of evidence from geological and geophysical observations indicate the deep subduction of continental lithosphere; however, the potential and driving forces of (self-sustained) continental subduction remain unclear. Here, systematic thermal-petrological models were conducted to quantitatively evaluate the subductability of continental lithosphere by analyzing its density structure and slab-pull evolution during subduction. The results indicate that the metamorphic densification of deeply subducted continental lithosphere (upper, middle, lower crust and lithospheric mantle) could provide considerable driving force for continental deep subduction. The numerical models further indicate that, if a Phanerozoic or Proterozoic continental lithosphere is dragged to a large depth of >300 km, then the continental slab pull overcomes the overall resistance force. Consequently, the continental subduction occurs self-consistently without any drag from the preceding oceanic slab. For Archean continental lithosphere, it is more difficult for self-sustained subduction to occur, due to the highly depleted mantle composition. In addition, we also systematically quantified the effects of multiple factors, including the scraping of continental crust, subduction velocity, subduction angle, and variable bulk-rock compositions of continental crust. Finally, a representative case study of the Himalayan orogen revealed that the slab pull of presently subducting Indian continental lithosphere ranges from 13 TN/m to 29 TN/m, providing a major contribution for the ongoing India-Asia collision.

Structural nature of pyroelectric effect revisited: Experimental and theoretical studies of synthetic Ni,Al - rich tourmaline

Tourmaline, the first pyroelectric material discovered, is also a promising borosilicate material with non-linear optical and luminescence properties, high thermal stability, high hardness and variable chemical composition. The structural nature of pyroelectricity in tourmaline is a subject of scientific debate since it requires precise structural studies and measurements at elevated temperatures. Here, an in situ high temperature single-crystal and powder X-ray diffraction studies (up to ∼1000 °C) and the direct pyroelectric measurements (up to ∼200 °C) of synthetic Ni, Al-rich tourmaline were performed. The pyroelectric coefficient was calculated from the structural data. The results demonstrate that polyhedra XO9, YO6 and ZO6 exert the greatest influence on the pyroelectric effect. The pyroelectric coefficient of tourmaline is practically independent of boron-oxygen triangles and silicon-oxygen tetrahedra. The primary pyroelectric coefficient of tourmalines could be calculated from single crystal structural data. This study contributes to the synthesis of tourmalines with the required pyroelectric properties and may be used for the study of the nature and properties of other pyroelectric materials.

Geochemical evidence for terrigenous sediment recycling in the Late Permian subcontinental lithospheric mantle of the northern North China Craton

Understanding the recycling process of subducted slab in subduction zones is vital to deciphering the heterogeneity of cratonic mantle and the variable compositions of continental arc igneous rocks. This study presents a comprehensive analysis of zircon U-Pb ages, Hf-O isotopes, hornblende major elements, whole-rock major and trace elements, as well as Sr-Nd-Hf isotopes of mafic igneous rocks from the northern North China Craton. These data constrain metasomatic processes in the cratonic mantle. The Late Permian mafic igneous rocks (ca. 254−252 Ma) studied are characterized by arc-like trace element signatures and enriched whole-rock Sr-Nd-Hf isotopes, with (87Sr/86Sr)i ratios of 0.7063−0.7076, εNd(t) values of −18.0 to −9.3, and εHf(t) values of −29.7 to +0.5. In addition, they also have elevated zircon δ18O values of 5.9‰−7.0‰, and variable zircon εHf(t) values of −19.4 to +6.0. These features suggest the rocks were derived from an enriched mantle with the involvement of terrigenous sediments. We propose that the subcontinental lithospheric mantle of the northern North China Craton was mainly metasomatized by terrigenous sediment-derived hydrous melt during the southward subduction of the Paleo-Asian Ocean. Moreover, partial melting of the metasomatic mantle may be triggered by the slab rollback related to the closure of the Paleo-Asian Ocean in the Late Permian, which resulted in the formation of the mafic igneous rocks studied. Thus, the Late Permian igneous rocks studied provide petrological and geochemical evidence of the crust-mantle interaction during the subduction of the Paleo-Asian Ocean.

Manipulating the d- and p-Band centers of amorphous alloys by variable composition for robust oxygen evolution reaction

Amorphous electrocatalysts display several unique advantages in electricity-driven water splitting compared to their crystalline analogs, but understanding their structure–activity relationships remains a major challenge. Herein, we show that the d- and p-electronic states of amorphous Ni-Fe-B can be subtly manipulated by varying the Ni and Fe contents. The optimal Ni-Fe-B alloy exhibits a high performance in the oxygen evolution reaction (OER), as supported by its impressive stability (no clear degradation after 100 h) and considerably lower overpotential compared to those of its crystalline analogs. Based on theoretical calculations, different Ni and Fe contents can cause significant shifts in the d-band levels of Ni and Fe and the p-band level of B, thus altering the OER activity. Additionally, the energy difference between the d- and p-band centers (ΔEad-p) may be an effective index for use in reflecting the structure–activity relationship of an amorphous Ni-Fe-B alloy in the OER. An amorphous Ni-Fe-B alloy with a smaller ΔEad-p displays a higher intrinsic activity. This study supplies a unique direction for use in constructing the structure–activity relationships of amorphous electrocatalysts by revealing the role of ΔEad-p, which promotes fundamental research and the practical application of amorphous electrocatalysts.

A Method to Determine the Optimal Period for Field-Scale Yield Prediction Using Sentinel-2 Vegetation Indices

This study proposes a method for determining the optimal period for crop yield prediction using Sentinel-2 Vegetation Index (VI) measurements. The method operates at the single-field scale to minimize the influence of external factors, such as soil type, topography, microclimate variations, and agricultural practices, which can significantly affect yield predictions. By analyzing historical VI data, the method identifies the best time window for yield prediction for specific crops and fields. It allows adjustments for different space–time intervals, crop types, cloud probability thresholds, and variable time composites. As a practical example, this method is applied to a wheat field in the Po River Valley, Italy, using NDVI data to illustrate how the approach can be implemented. Although applied in this specific context, the method is exportable and can be adapted to various agricultural settings. A key feature of the approach is its ability to classify variable-length periods, leveraging historical Sentinel-2 VI compositions to identify the optimal window for yield prediction. If applied in regions with frequent cloud cover, the method can also identify the most effective cloud probability threshold for improving prediction accuracy. This approach provides a tool for enhancing yield forecasting over fragmented agricultural landscapes.

Whole UVCB Tests Can Yield Biotic and Abiotic Degradation Kinetics of Known and Unknown Constituents for an Enhanced UVCB Degradation Profile

The green transition and move towards safe and sustainable-by-design chemicals entail the need for new methods to study the biodegradability of UVCBs (substances of Unknown or Variable composition, Complex reaction products and Biological materials). Standard simulation biodegradation tests have been developed for single substances and are generally not applicable for UVCBs. The aims of this study were (1) to combine a whole UVCB biodegradation test with a sensitive constituent specific analytical technique, (2) to measure biotic and abiotic degradation of known and unknown UVCB constituents and (3) to determine the impact of a WWTP discharge on the constituent specific biodegradation in stream water. Lavender oil and black pepper oil are of significance in the perfume and cosmetics industries and served as model UVCBs. Stream water sampled upstream and downstream of a wastewater treatment plant (WWTP) discharge point was used as inoculum (i.e., naturally and wastewater adapted bacterial consortia). Tests were conducted in gastight headspace vials and automated Arrow Solid Phase Microextraction GC-MS-scan was applied on unopened vials. Peak area ratios between biotic test systems and abiotic controls were used to determine primary biodegradation kinetics, and freshly spiked analytical references to separate biotic from abiotic degradation. Biodegradation half-times were below 20 days for all known (8-12) and unknown constituents (>78) in the essential oils. Dual column GC-MS analysis produced a level 2 identification of 16 unknown lavender constituents. Biodegradation kinetics were similar in inoculum taken before and after the WWTP outlet, confirming that native stream microorganisms were competent degraders.

Indigenous bio-coagulant assisted electrocoagulation process for the removal of contaminants from brewery wastewater: Performance evaluation and response surface methodology optimization

Wastewater from human activities, particularly from brewery industries, is a significant source of pollution. Large volumes of biodegradable and non-biodegradable substances found in brewery effluent make them suitable for natural coagulant-assisted electrocoagulation. The treatment options available today are highly harmful and not economical. To solve this problem and provide a simple method of treating brewery wastewater, the biocoagulant (Custard apple)-assisted electrocoagulation process was created. This study presents an environmentally friendly way of treating wastewater by combining electrocoagulation with biocoagulant. The approach treats wastewater from breweries with a high organic load and a variable composition. Bio- and electrocoagulation are used in the process to target certain contaminants and when combined the method has high efficiency and is environmentally also friendly. The performance of bio-coagulant-assisted electrocoagulation was studied, considering parameters such as pH, time, current, and bio-coagulant dosage. In each experiment, operating parameters were adjusted and their removal efficiency was evaluated after treatment. The bio-coagulant-assisted electrocoagulation process removed COD (99.01 %), BOD (99.09 %), TDS (99.02 %), and) at an ideal pH of 7, a current of 0.5 A, a time of 40 min, and power consumed (0.54kwh/m3) with a constant dose of 0.75 g/l NaCl as electrolytes. The study found that Indigenous bio-coagulant (Custard apple)-assisted electrocoagulation processes were effective and efficient in removing pollutants from brewery wastewater. In the process of treatment operating factors have a high effect on the performance of the method. The parameters were customized using Response Surface Methodology (RSM), and the dependent variable's value was determined through regression analysis with a design expert.

Bone marrow magnetic resonance imaging (MRI): morphological and functional features from reconversion to infiltration.

Bone marrow is a dynamic organ with variable composition in relation to age or pathophysiological changes. Magnetic resonance imaging (MRI) is the technique of choice to assess the different components of the bone marrow based on the different information provided by the different characteristics of the MRI sequences. This article provides an overview of the MRI appearances of normal and abnormal bone marrow. We review the MRI features of normal developmental red marrow- to yellow-conversion, reconversion and physiologic conditions. We review the key imaging techniques used in assessing bone marrow pathology in MRI, including T1-weighted, T2-weighted, Dixon chemical shift imaging and diffusion-weighted imaging, as well as dynamic contrast-enhanced (DCE) MRI. It is discussed the bone marrow characteristics in the different morphological and functional MRI sequences from the normal or abnormal conditions such as; infiltration (metastases), proliferation [multiple myeloma (MM)], vascular edema/necrosis and postreatment changes. We show the different MRI features to differentiate physiological processes from pathological processes in order to provide effective diagnoses, as well as to evaluate the optimal therapeutic monitoring assessment. Insights from recent advancements in imaging technology and emerging MRI techniques are also discussed, providing a comprehensive overview of bone marrow MRI and its clinical implications. This review provides a useful tool for radiologist to decide normal or abnormal findings from the analysis of bone marrow MRI; in order to manage and take decisions that will depend on the imaging findings. The optimal analysis of bone marrow MRI requires knowledge of the physiology of the bone marrow to interpret properly the pathology and avoid diagnostic errors.

Definition and Validation of a Zero-Dimensional IC Engine Model for Assessing the Performance of Different Methane-Hydrogen Mixtures

Abstract To decarbonize the maritime transport sector, a solution inspired by the automotive industry involves using a solid oxide fuel cell (SOFC) in conjunction with an internal combustion engine. For optimal emission efficiency, the internal combustion engine is fueled with a primary fuel, typically methane already on board for feeding the SOFC, plus anode off-gases from SOFC, which are a mixture of variable composition of hydrogen, carbon dioxide, and carbon monoxide. To assess the performance of the integrated system (SOFC+ICE) and subsequently search for an optimal set-up, it is useful to use a zero-dimensional model of each component of the system. Particularly, the internal combustion engine model must balance speed of execution with flexibility in terms of fuel composition, engine dimensions, and other relevant parameters. In this study, an engine model originally developed for gasoline-fueled ICE, is adapted for variable methane-hydrogen mixtures. The model is validated against experimental data measured on an engine operating with similar mixture compositions and available in the literature.

Low-cost fabrication of digital light processing 3D printed conical microneedles for biomedical applications

The 3D printing of microneedles has become an emerging area of research focus due to its ability to rapidly create microneedle arrays with parametrically variable geometry and composition. Through direct fabrication or via replica molding, 3D printed microneedles can facilitate iterative array assessment and act as a screening tool to quickly establish optimal parameters for tissue insertion and capacity for biomarker monitoring or drug release. However, the widespread adoption of 3D printing by microneedle array researcher group faces multiple barriers: (1) Investment in 3D printing systems that are traditionally associated with high-resolution pose a significant financial cost, (2) Current high-resolution printing methods are often slow and not conducive to rapid manufacturing, (3) Material selection can be limited in some ‘proprietary’ 3D printing systems (e.g. CLIP, SLA, or 2PP), (4) Given the multidisciplinary nature of the microneedle-field, researchers may not have the expertise to optimize printing parameters for a given material or printer. This work explores how ultra-low-cost digital light processing (DLP) printers can rapidly produce functional microneedle arrays for a variety of purposes, whether direct print, master mold production, or creation of coated microneedles, at a fraction of the cost of currently used systems. Further, this work highlights that high quality microneedle arrays can be created using DLP printing methods with reliability exceeding 98 %, tip radii on the order of 30 µm, and with appropriate parameter input optimization, high quality microneedle arrays can be fabricated that express desirable characteristics for multiple forms of solid microneedle array production.

Diagnosis of marine internal combustion engines by means of rapidly variable temperature and composition of exhaust gas as an alternative or support for currently used diagnostic methods

The article points out relevance of parametric diagnostics of ship engines and analyzes the state of research in this field. A method is proposed for diagnosing engine systems on the basis of rapidly variable exhaust temperature while measuring its composition. A method for determining diagnoser tools from the signal within one engine cycle and mathematical and statistical treatment of test results is presented. The products of numerical moddeling in the Diesel-RK software and the products of laboratory research on a Farymann Diesel test engine were analyzed. Affect of the most popular defects on the analyzed parameters was defined. Criteria for matching a diagnoser tool in accordance with the type of damage in a ship engine was presented. A methodology was proposed for adapting the presented method to metering on a ship engine in operation.