Debris Concentration Research Articles

Study of turbulence effects on flying compact debris in tornadoes at different stages

Flying debris is an important factor influencing the destruction of buildings by tornadoes. However, research on tornado-borne debris remains limited. Thus far, the degree of this influence and methods to consider turbulence effects when predicting debris motion using the statistical information of wind velocities in tornadoes, have not been clarified. Therefore, in the present study, four methods for calculating debris motion based on the mean wind velocities and the root mean square of wind velocity fluctuations were examined. These four methods entailed (a) using only the mean wind velocities, (b) using Karimpour corrections, (c) assuming that the instantaneous flow fields of the tornado fluctuate as sinusoidal functions, and (d) assuming that the probability density functions of the instantaneous wind velocities follow Gaussian distributions. It was found that the debris concentration were sensitive to the turbulence in tornadoes. The Gaussian-distribution assumption afforded the best performances and could provide almost perfect predictions, except for the tornado-core regions.

Organic matter oxidation of the Tégulines Clay formation, (Paris Basin, France): Spatial Heterogeneities

Samples of Albian Tégulines Clay outcropping near Brienne-le-Château in the eastern part of the Paris Basin were subjected to a geochemical characterization of organic matter (OM), combining OM bulk Rock-Eval analysis (RE), organic petrography and molecular analysis. In this study, the objective was to investigate the oxidation of natural organic matter in critical zone developed in early reduced marine clay formation. For that purpose, core samples from three boreholes crosscutting the Tégulines Clay formation down to the Greensands were selected. Several meters of Brienne marls preserved Tégulines Clay from atmosphere and therefore from high weathering and high oxidation in AUB240 borehole, whereas Tégulines Clay were weathered in their upper part in AUB1010 and in AUB230 boreholes as a result to their vicinity to the surface. The results showed that the Total Organic Carbon (TOC) contents in all clays are very low, ranging between 0.3 and 0.7 wt%. The RE bulk data and Tmax parameter of OM in preserved Tégulines Clay indicate that the OM is immature. The organic petrography shows a predominance of gel-like amorphous OM preserved by natural sulphurisation in anoxic environments. Organic matter in Tégulines Clay from the AUB230 and AUB1010 boreholes show similar characteristics. The OM at the top of Tégulines Clay contains large amounts of oxidized lignocellulosic debris and has high RE Oxygen-Index values. In the first upper 10 m of the clays, the RE bulk, organic petrography and molecular data revealed oxidative events (high OI and high oxidized debris contents). Below 10 m, the OM is almost preserved. The OM in the reduced marine Tégulines Clay formation is very little functionalized and seems to be slightly reactive but not negligibly with the inorganic fractions in presence of oxygen.

Ecological Traits Influencing Anthropogenic Debris Ingestion by Herbivorous Reef Fishes

One of the most conspicuous marks of the Anthropocene worldwide is the ubiquitous pollution by long lifespan materials (e.g., plastic). In marine habitats, anthropogenic debris are observed from floating on the surface to deposited on the substrate or ingested by wildlife at different food web levels. However, the link between feeding strategy types and debris ingestion by reef fishes remains poorly explored. We analyzed the gut contents of three nominally herbivorous fishes along the Brazilian coast: the doctorfish Acanthurus chirurgus, the parrotfish, Sparisoma axillare, and the chub Kyphosus vaigiensis. Individual [i.e., total length (TL)] and species-level functional traits, as well sites with distinct environmental features (i.e., tourism activity intensity, fishing pressure, and distance from the coast), were tested as predictors of the concentration of debris found inside individual fish guts. Debris found were quantified, measured, and classified accordingly to color and shape. We found debris in 52.7% of individuals. Debris ranged from 0.10 to 11.75 mm, and the frequency of occurrence and ingestion rate (number of debris per individual) varied among species, being higher for the scraper species S. axillare (95.7% and 4.9 ± 1.2, respectively) and A. chirurgus (74.6% and 1.64 ± 0.34), than for the browser K. vaigiensis (55.8% and 0.83 ± 0.24). TL, scraping feeding mode, and the most impacted location were positively related to debris ingestion rate. Our work revealed a higher vulnerability of an ecologically important trophic group to debris ingestion and of an already threatened species according to Brazilian red list. Besides the increasing number of species contaminated by anthropogenic debris, its effect on fish biology and physiology remains poorly understood. Understanding these links would improve conservation planning as species contamination could act as a proxy for environmental pollution on marine habitats.

Applications Characteristics of Different Biodiesel Blends in Modern Vehicles Engines: A Review

Two main aspects of the transportation industry are pollution to the environment and depletion of fossil fuels. In the transportation industry, the pollution to the environment can be reduced with the use of cleaner fuel, such as gas-to-liquid fuel, to reduce the exhaust emissions from engines. However, the depletion of fossil fuels is still significant. Biodiesel is a non-toxic, renewable, and biodegradable fuel that is considered an alternative resource to conventional diesel fuel. Even though biodiesel shows advantages as a renewable source, there are still minor drawbacks while operating in diesel engines. Modern vehicle engines are designed to be powered by conventional diesel fuel or gasoline fuel. In this review, the performance, emissions, combustion, and endurance characteristics of different types of diesel engines with various conditions are assessed with biodiesel and blended fuel as well as the effect of biodiesel on the diesel engines. The results show that biodiesel and blended fuel had fewer emissions of CO, HC, and PM but higher NOx emissions than the diesel-fuelled engine. In the endurance test, biodiesel and blended fuel showed less wear and carbon deposits. A high concentration of wear debris was found inside the lubricating oil while the engine operated with biodiesel and blends. The performance, emissions, and combustion characteristics of biodiesel and its blends showed that it can be used in a diesel engine. However, further research on long-term endurance tests is required to obtain a better understanding of endurance characteristics about engine wear of the diesel engine using biodiesel and its blends.

Lubricating oil deterioration modeling and remaining useful life prediction based on hidden semi-Markov modeling

Lubricating oil, which carries information about machine’s health condition, is of great importance to the performance of machines in the full life cycle. The main purpose of oil deterioration modeling and its remaining useful life prediction is to determine the exact time that the lubricating oil has degraded and it is no longer able to maintain its functions. Generally, lubricating oil deterioration can be partially detected by condition monitoring based on wear debris analysis, and thus can be categorized into three states. In our paper, vector data, which contain wear debris concentration and carry information about the state of lubricating oil, are obtained by an on-line visual ferrograph sensor from a four-ball tester at regular sampling epochs. The oil’s state process is described by a hidden semi-Markov model, and its sojourn times in each state are assumed to be Erlang distributed. A vector autoregressive method based on time series modeling is presented to obtain residual observations, which are regarded as the observable process of oil information in the hidden semi-Markov model framework. The unknown parameters of the hidden semi-Markov model are then estimated by using expectation-maximization algorithm. Afterward, a Bayesian updating approach is presented to derive the explicit formulas of the conditional reliability and mean residual life. To validate the proposed approach, a real case study of lubricating oil deterioration is demonstrated and a comparison with the hidden Markov model is given to illustrate the effectiveness of the new developed remaining useful life prediction approach for lubricating oil.

The Causes of Debris-Covered Glacier Thinning: Evidence for the Importance of Ice Dynamics From Kennicott Glacier, Alaska

The cause of debris-covered glacier thinning remains controversial. One hypothesis asserts that melt hotspots (ice cliffs, ponds, or thin debris) increase thinning, while the other posits that declining ice flow leads to dynamic thinning under thick debris. Alaska’s Kennicott Glacier is ideal for testing these hypotheses, as ice cliffs within the debris-covered tongue are abundant and surface velocities decline rapidly downglacier. To explore the cause of patterns in melt hotspots, ice flow, and thinning, we consider their evolution over several decades. We compile a wide range of ice dynamical and mass balance datasets which we cross-correlate and analyze in a step-by-step fashion. We show that an undulating bed that deepens upglacier controls ice flow in the lower 8.5 km of Kennicott Glacier. The imposed velocity pattern strongly affects debris thickness, which in turn leads to annual melt rates that decline towards the terminus. Ice cliff abundance correlates highly with the rate of surface compression, while pond occurrence is strongly negatively correlated with driving stress. A new positive feedback is identified between ice cliffs, streams and surface topography that leads to chaotic topography. As the glacier thinned between 1991 and 2015, surface melt in the study area decreased, despite generally rising air temperatures. Four additional feedbacks relating glacier thinning to melt changes are evident: the debris feedback (negative), the ice cliff feedback (negative), the pond feedback (positive), and the relief feedback (positive). The debris and ice cliff feedbacks, which are tied to the change in surface velocity in time, likely reduced melt rates in time. We show this using a new method to invert for debris thickness change and englacial debris content (∼0.017% by volume) while also revealing that declining speeds and compressive flow led to debris thickening. The expansion of debris on the glacier surface follows changes in flow direction. Ultimately, glacier thinning upvalley from the continuously debris-covered portion of Kennicott Glacier, caused by mass balance changes, led to the reduction of flow into the study area. This caused ice emergence rates to decline rapidly leading to the occurrence of maximum, glacier-wide thinning under thick, insulating debris.

Simulation and experimental investigation of performance characteristics of dry and near dry EDM process

ABSTRACT In many industrial applications, necessity of new age materials; however some typical alloys like spring steel material are used in critical sector such as defence, aerospace, and automobile. To work on spring steel material, there are several difficulties such as hard to cut, low material removal rate, and high energy consumption. The EDM is critical thermal evacuation process. This paper presents the result of experimentation and simulation carried out on a spring steel material by varying current, gap voltage, cycle time and pressure. The experimental results are verified by developing a thermal-electrical model of workpiece material using ANSYS workbench. Transient thermal analysis is used to simulate the electric discharge machining. The finite element method (FEM) analysis includes spark radius variation and temperature profile formation by electric discharge. It is found that the dielectric fluid pressure is closely related to the discharge environment, such as debris concentration and fluid viscosity. Further, it is found that distilled water provides more stability to plasma channel in near dry electric discharge machining (NDEDM) compared to dry electric discharge machining (DEDM). From the results obtained, it is concluded that the material removal rate is affected by dielectric medium properties viz. dielectric strength, dielectric constant and thermal conductivity.

A Full Field-of-View Online Visual Ferrograph Debris Detector Based on Reflected Light Microscopic Imaging

For improving the detection accuracy of wear debris visual information for online wear monitoring, a full field-of-view Online Visual Ferrograph (OLVF) debris detector is presented. In current OLVF debris detector, a semi-transparent optical diffusion film is clamped into the gap between the bottom optical quartz window and two magnetic poles as the background of full field-of-view OLVF microscopic imaging, by which the emitted light of circular ring LED array is diffusely reflected. A reflected light microscopic imaging system is developed to form the full field-of-view imaging of OLVF, and a mathematical relationship between its depth of field and the oil-pumping and oil-free axial deviations of CMOS image plane is established, by which the oil chamber height can be determined. An optical focusing mechanism is applied to adjusting the optical magnification and the optical resolution of about 7.2 μm is derived under 2.0× optical magnification. Moreover, a microscopic imaging model is proposed to evaluate the characteristics of full field-of-view OLVF microscopic imaging. The simulation results show that the high-quality microscopic imaging can be obtained near the optical axis of CMOS image plane under 2.0× optical magnification and oil attenuation coefficient of less than 2.0. Two experiments were conducted to validate the microscopic imaging performance and effectiveness of the current detector. The results show that the detector can be applied for capturing the full field-of-view reflected ferrogram of wear debris from different in-use lube oils, and it can also detect debris concentration more accurately for monitoring the fast-changing wear of the machines.

Condition based predictive maintenance of worm gearbox using DR ferrography

Due to inadequate and incorrect information about the state of the equipment, the maintenance person may be unable to make maintenance decisions. Modern maintenance ideas are focused on the implementation of equipment predictive maintenance to address this problem. DR Ferrography is a predictive maintenance technique which provides the data of condition of the lubricants and also the condition of the equipmentelements that interacted with oil during normal operation. A case study of a worm gearbox is discussed to demonstrate the usefulness of a DR Ferrography technique. An experimental test rig is used to model the worm gearbox. The worm gearbox operates under normal operatingconditions as per industrial practice. DR Ferrography is a useful method for detecting wear particles in lubricating oil. According to the findings, wear debris indicates device performance based on wear debris concentration and wear severity index, leading to early component breakdown detection and prediction.

A deposition rate based index of debris concentration and its extraction method for on-line image visual ferrography

On-Line image visual ferrography (OLVF) is an acquisition device of oil debris information, which is affected significantly by the aggregation and overlap of wear debris and air bubbles in practice. In this work, a debris deposition video from OLVF is recorded as raw data. A relationship between wear debris concentration and debris deposition rate in a deposition process of OLVF is derived. Based on this, a deposition rate based index of debris concentration (IDC) from OLVF video is proposed. A matching algorithm is developed to calculate the IDC. Moreover, a full-life accelerated gear wear test is performed, in which a total of 1505 bubble-debris videos are obtained by the OLVF. The verification results show that the approach can not only overcome the interference of air bubbles but also avoid the error of saturation nonlinearity caused by agglomeration and overlap of wear debris, and that the proposed IDC performs better than previous index of particle coverage area (IPCA).

Evolution of a fluvial-dominated delta during the Oligocene of the Colombian Caribbean: Sedimentological and ichnological signatures in well-cores

Basin analysis from Colombian Caribbean is particularly important given the interest in finding hydrocarbon reservoirs, but their complex geological evolution, and the frequent lateral and vertical variation of facies difficult a conclusive characterization, highlights the need for detailed sedimentological and ichnological studies. The study succession corresponds to an interval of a well core drilled in the south of the Sinú-San Jacinto Basin (Colombian Caribbean), with 1069 ft (~326 m) thick of an Oligocene siliciclastic succession, interpreted in general terms, as deposited in a deltaic system. The integrated sedimentological/ichnological analysis allows the differentiation of dominant facies, with predominant lithologies such as conglomerates, sandstones, mudrocks, bioclastic sediments, as well as coal beds. The ichnological assemblage is low in abundance and moderately diverse, composed by Conichnus, Cylindrichnus, Dactyloidites, Macaronichnus, Ophiomorpha, Phycosiphon, Skolithos, Taenidium, Teichichnus, and Thalassinoides, as well as rhizoliths.The complexity of the sedimentary system is reflected in its evolution throughout the Oligocene. A type succession with coarsening-upward trend was identified and it is repeated through the succession studied. It presents a general trend from bioclastic sediments (bioclastic conglomerates, sandstones and mudrocks) that pass into horizontal lamination and massive mudrocks occasionally bioturbated by Phycosiphon, and interbedded by mudrocks and sandstones with lenticular bedding, and the occurrence of Teichichnus. Above, bioturbated muddy sandstones with Ophiomorpha, Taenidium, Thalassinoides, and rarely Teichichnus, muddy sandstones with planar cross-lamination, and horizontal lamination sandstones with Dactyloidites, Ophiomorpha, Skolithos, and Thalassinoides are registered. Transition to carbonaceous mudrocks with Teichichnus, coal medium beds, and fine-to coarse-grained sandstones sometimes with Macaronichnus and/or Ophiomorpha is observed. Towards the top, are observed mudrocks with rhizoliths. This succession is interrupted by massive and horizontal lamination sandstones with low bioturbation index generated by the ichnological assemblage and/or by the exclusive occurrence of Ophiomorpha and/or Taenidium. Massive sandstones with erosive bases, asymmetrical ripples, and high content of organic debris are occasionally recorded. This succession reflects a progradational trend similar to those of fluvial-dominated deltaic sequences.Detailed analysis revealed that even the fluvial processes were dominant in the deltaic system; however, local tidal and wave influence is recorded. Moreover, integration of sedimentological and ichnological information allows characterizing the evolution of the different sub-environments of the deltaic system, as prodelta bay, distal delta front, proximal delta front, distributary channels, mouth bars, and lower delta plain, and this is essential for areas of economic interest.

Assessment of Marine Debris and Plastic Polymer Types Along the Panvel Creek, Navi Mumbai, West Coast of India

Marine debris was collected monthly from substations along Panvel creek from May 2020 to April 2021 and was analyzed for types of non-plastic debris and plastic debris. Plastic debris was assessed for % composition of a type of plastic, plastic polymer and further categorized according to plastic code, acronym, full name and common examples. Non-plastic debris of 8 types representing 38 items were recorded. Consumer and manufactured items like glass and plastic bottles, cans, bags, rubber, metal, fiberglass, cigarettes, fishing gears etc. were observed. 8 types of polymers representing 65 items were recorded along Panvel creek. Plastic polymers like Polyethylene terephthalate (PETE/PET), High density polyethylene (HDPE), Polyvinyl chloride (PVC), Low density polyethylene (LDPE), Polypropylene (PE), Polystyrene (PS), Polyamide/Nylon, Acrylonitrile Butadiene Styrene (ABS) and Polyurethane (PU) were recorded. 13 items belongs to Plastic code 2:HDPE, 12 to 3:PVC, 11 to 5:PP, 9 to 6:PS, 8 to 4:LDPE, 6 to 1:PETE/PET and 3 each to 7:PA and Other and 8:PU, respectively, were documented. Maximum % composition (20.00%) of HDPE, and minimum (4.61%) of PA and Other and PU, respectively was recorded. Higher content of debris recorded is attributed to the disposal of domestic wastes intentionally or unintentionally into the creek and also for disposal of scrap materials from the fishing crafts. Higher HDPE content is attributed to the wastes released from the fishing vessels and also to the domestic and municipal wastes. At present the Panvel creek is moderately polluted and 3R i.e. reduce, reuse and recycling is the current solution to the overuse of plastics.

Periprosthetic Osteolysis in Cervical Total Disc Arthroplasty: A Single Institutional Experience

ABSTRACT BACKGROUND Cervical disc arthroplasty (CDA) affords an excellent alternative to cervical fusion for the treatment of symptomatic patients with degenerative disc disease. As more surgeons perform CDAs, an understanding of the complications associated with this technique is crucial. Periprosthetic osteolysis (PO) is a rare potential complication associated with CDA. OBJECTIVE To highlight potential complications associated with CDA. METHODS A retrospective chart review of patients who underwent CDA at our institution was performed. Patient outcomes and relevant clinical and radiographical data were analyzed in addition to associated complications. Explanted devices were subjected to macroscopic and microscopic analyses. RESULTS A total of 88 patients were included: 68 patients underwent 1-level CDA and 20 patients had 2-level CDA. Implants used in this series included Mobi-C (Zimmer Biomet), Prestige LP (Medtronic), Secure C (Globus), Advent (Orthofix), and ProDisc C (DePuy). One patient demonstrated symptoms of myeloradiculopathy that correlated with radiographical periprosthetic osteolysis and required surgical intervention in the form of disc explantation, corpectomy, and cervical instrumented fusion. Device retrieval analysis demonstrated evidence of elevated oxidation levels and increased wear in the presence of high concentrations of metal ions and debris in the surrounding tissue. The tissue did not exhibit any immune response, infection, or acute inflammation. CONCLUSION PO is a potential complication of CDA that occurs irrespective of the type of implant used. We describe its occurrence and management and highlight the importance of being aware of this understated phenomenon.

Desgaste das próteses da articulação temporomandibular: uma revisão narrativa

Temporomandibular joint (TMJ) prostheses can be a stock or custom-made replacement of the related maxillomandibular structures such as condyle and fossa. In the last years, several materials and design have been assessed in an attempt to improve the mechanical performance of TMJ prostheses. This study aims to report literature data on the wear of temporomandibular joint prostheses and potential biological risks to the patients. Studies reported a significant deterioration of the sliding contact surfaces of TMJ prostheses. Material loss as a result of wear causes condyle/fossa mismatch and the modification of contact pressure and chewing forces loading. As a further consequence of wear, metal particles are released to the surrounding tissues with a high risk of local tissue toxicity and systemic toxicity through the bloodstream. The presence of particles induces the stimulation of inflammatory reactions depending on the concentration and size of debris.

A Preliminary Analysis of the Wear Pathways of Sliding Contacts on Temporomandibular Joint Total Joint Replacement Prostheses

In the last years, several materials and design have been assessed in an attempt to improve the mechanical performance of temporomandibular joint total joint replacement (TMJ TJR) prostheses. However, the wear of the TMJ TJR condyle to the polymer-based fossa component during loading and sliding movements. That promotes the release of debris and risks of toxicity to the surrounding tissues. The purpose of this study was to perform a narrative literature review on the wear of TMJ TJR sliding contacts and potential toxicity of metallic debris to the patients. Previous studies reported a significant deterioration of the sliding contact surfaces of TMJ TJR prostheses. Material loss as a result of wear can cause a TMJ TJR condyle/fossa mismatch and the modification of the contact pressure and chewing loading. As a further consequence of wear, metal particles are released to the surrounding tissues with a high risk of local tissue and systemic toxicity through the bloodstream. The presence of particles induces the stimulation of inflammatory reactions depending on the concentration and size of debris. Thus, CoCr-based condyle release metallic ions and sub-micron particles that can be engulfed by macrophages or internalized by other tissue cells. The wear and material loss of TMJ TJR could be decreased by design optimization and novel materials with low friction and contact pressure. That consequently decrease the amount of metallic ions and particles to the surrounding tissues, preventing peri-prosthetic inflammatory reactions.

The activities of Geopolymer aggregate and Fly ash with different Grades of concrete M25, M30, & M40

Endeavors are expected to grow harmless to the ecosystem development materials, to diminish ozone depleting substance outflows. This paper persents the exercises of geo polymer total and fly debris with various evaluation of M25, M30 and M40. We are confronting climate issue because of greatest utilization of normal development material, to diminish this kind of issue this paper is a thought of renewal and utilization of contamination free, eco-accommodating, development material for example fly debris. Fly debris assumes an indispensable part in the creation cycle of Geopolymer in light of Quantity and fineness. In geopolymer concrete, a result material wealthy in silicon and alumminium, for example, low-calcium fly debris, is synthetically actuated by a high-soluble answer for structure a glue that ties the free coarse and fine totals, and other unreacted material in the blend.
 Concrete is one of the greatest devoured essential development materials on the planet with an imperative job in the development field. Assembling of one ton of concrete delivers almost one ton of CO2 causing natural issues. So there is a need to diminish concrete creation and utilize a few added substances to make concrete economical. Because of developing ecological mindfulness, there is a heightening interest in the utilization of fly debris. It tends to be utilized either as an admixture or as fragmentary substitution of concrete or as fractional substitution of fine total and furthermore as beneficial expansion to accomplish various properties of cement. This paper presents the trial examinations on the impact of fly debris content on compressive strength of M25, M30 and M40 evaluations of cement at an age of 3, 7, and 28.
 Because of higher finess shows higher workbability, strength with early length of warming. In this examination the strength properties of cement of M-40 evaluation can be dissected by supplanting concrete by pozzolanic materials like Fly Ash and actuated by profoundly antacid answers for go about as a fastener in blend.
 Utilization of Cement in any nation is straightforwardly identified with the nation's foundation and along these lines development in deciding the improvement of the country. India is the second biggest maker of concrete on the planet. Creation of Portland concrete not just deliveries 7% of the World's carbon dioxide, the concrete business likewise utilizes a great deal of characteristic property like limestone, earth, oil, coal and different substances to save the common assets and to lessen the contamination because of the creation of concrete is by prohibitive the concrete substance in the solid without bargaining the strength. Concrete has a negative effect over Environmental, in light of the fact that at the hour of assembling it radiates about a huge load of ozone harming substance (CO2) into the air for each huge load of concrete manufactured.There were endeavors before to incompletely supplant concrete in concrete with new mixtures and industry results.

Marine Debris and Trace Metal (Cu, Cd, Pb, and Zn) Pollution in the Stranded Green Sea Turtles (Chelonia mydas).

Marine debris and trace metals are among the common environmental contaminants known to affect marine organisms. In this study, the quantitative and qualitative aspects of marine debris levels and bioaccumulation of trace metals (Cadmium: Cd; Copper: Cu; Lead: Pb; and Zinc: Zn) were investigated in 42 green sea turtles (Chelonia mydas) stranded on the northern coast of the Sea of Oman. The greatest quantity of debris was found in the intestine, stomach, and esophagus of the animals, respectively. Results of a Marine Strategy Framework Directive (MSFD) subcategory analysis of the ingested debris showed that sheet and thread-like plastics were the most frequently detected debris followed by various rubbish. The results revealed that white-colored debris were the most common debris, followed by black > green > blue > transparent > and brown ones. The results suggested that the rope monofilament was the main source of the ingested debris by the green sea turtles. Concentrations of the trace metals in the liver, kidney, and muscle ranged between 0.66-33.43, 0.36-15.12, and 0.33-7.47μg/g (ww), respectively. The results of this study suggest that ingested marine debris and tissue concentrations of trace metals are present at levels that may cause sublethal effects on green sea turtles (C. mydas) through potentially affecting the physiological processes and making the turtles susceptible to other natural or human threats. Results indicated that the green sea turtles from the northern coast of the Sea of Oman have high interaction with the marine debris. These factors are considered as a serious threat to the existence and survival of the green sea turtles (C. mydas) living on the northern coast of the Sea of Oman.

Similarities and Differences among Soil Fungal Assemblages in Managed Forests and Formerly Managed Forest Reserves

Unlike the numerous works concerning the effect of management on the forest mycobiome, only a few studies have addressed how fungi from different trophic groups recover from natural and anthropogenic disturbances and develop structural features typical of unmanaged old-growth forests. Our objective is to compare the soil fungal assemblages represented by different functional/trophic groups in protected and managed stands located in European mixed forests dominated by Scots pine. Fungal communities were analyzed using high-throughput Illumina MiSeq sequencing of fungal internal transcribed spacer 1 (ITS1) amplicons. Formerly managed forest reserves (established around 50 years ago) and forests under standard forest management appeared to be similar in terms of total and mean species richness of all fungal operational taxonomic units (OTUs), as well as OTUs assigned to different functional trophic groups. Among the 599 recorded OTUs, 497 (83%) were shared between both management types, whereas 9.5% of taxa were unique to forest reserves and 7.5% were unique to managed stands. Ascomycota and Basidiomycota were the predominant phyla, comprising 88% of all identified fungi. The main functional components of soil fungal assemblages consisted of saprotrophic (42% fungal OTUs; 27% reads) and ectomycorrhizal fungi (16%; 47%). Two-way analysis of similarities (ANOSIM) revealed that both site and management strategy influenced the species composition of soil fungal communities, with site being a primary effect for saprotrophic and ectomycorrhizal fungi. Volume of coarse and very fine woody debris and soil pH significantly influenced the ectomycorrhizal fungal community, whereas saprotrophic fungi were influenced primarily by volume of coarse woody debris and soil nitrate concentration. Among the identified fungal OTUs, 18 red-listed fungal species were identified from both forest reserves and managed forests, comprising two ECM fungi and four saprotrophs from the category of endangered species. Our results suggest that the transformation of fungal diversity after cessation of forest management is rather slow, and that both forest reserves and managed forests help uphold fungal diversity.

Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities.

Perforation behavior of 3 mm/3 mm double-spaced aluminum plates by PTFE/Al/W (Polytetrafluoroethylene/Aluminum/Tungsten) reactive projectiles with densities ranging from 2.27 to 7.80 g/cm3 was studied experimentally and theoretically. Ballistic experiments show that the failure mode of the front plate transforms from petalling failure to plugging failure as projectile density increases. Theoretical prediction of the critical velocities for the reactive projectiles perforating the double-spaced plates is proposed, which is consistent with the experimental results and well represents the perforation performance of the projectiles. Dimensionless formulae for estimating the perforation diameter and deflection height of the front plates are obtained through dimensional analysis, indicating material density and strength are dominant factors to determine the perforation size. High-speed video sequences of the perforation process demonstrate that high-density reactive projectiles make greater damage to the rear plates because of the generation of projectile debris streams. Specifically, the maximum spray angle of the debris streams and the crater number in the debris concentration area of the rear plate both increase with the projectile density and initial velocity.

Plastic debris composition and concentration in the Arctic Ocean, the North Sea and the Baltic Sea

Neuston samples were collected with a Manta trawl in the rim of the Arctic Ocean, in the Northern Atlantic Ocean and the Baltic Sea at eleven coastal and open-sea locations. All samples contained plastics identified by FTIR microscopy. Altogether, 110 microplastics pieces were classified according to size, shape, and polymer type. The concentrations at the locations were generally low (x̅ = 0.06, SD ± 0.04 particles m−3) as compared to previous observations. The highest concentrations were found towards the Arctic Ocean, while those in the Baltic Sea were generally low. The most abundant polymer type was polyethylene. Detected particle types were mainly fragments. The number of films and fibers was very low. The mean particle size was 2.66 mm (SD ± 1.55 mm). Clustering analyses revealed that debris compositions in the sea regions had characteristic differences possibly reflecting the dependences between compositions, drifting distances, sinking rates, and local oceanographic conditions.