Edge Zone Research Articles

INVESTIGATION OF DIFFERENT DEFORMATION SCHEMES FOR OBTAINING FINE-GRAIN STRUCTURE OF CAST ALUMINUM ALLOY AK 7

Abstract. The article investigated various schemes of deformation of the workpiece to improve the mechanical properties of the cast aluminum alloy AK 7. The most effective deformation schemes are spiral widening extrusion (SWE) and multi-angle pressing (MAP). Filling of a matrix most completely occurs at the SWE scheme, the degree of filling makes 90–95%. The depth of propagation of plastic deformation in the scheme of SWE is 6–9 mm. The results of numerical simulations correlate with the results obtained experimentally for the SWE matrix. It was experimentally determined that the increase in the accumulated shear deformation causes an increase in the values of microhardness. The magnitude of the accumulated deformation increases along the radial coordinate from the center to the edge of the workpiece. It was found that after the third transition in the central zone, the amount of accumulated deformation is approximately equal to the amount of deformation after the first pass in the edge zone. Mechanical properties, namely strength characteristics are increased. So after the first pass their values increase in relation to the source metal by 15%, after the second treatment by 20%, after the third by 25%.

In silico Prediction Followed By I n Vitro validation Identifies a Survivin Inhibitor and an MCL-1 Inhibitor As a Potent Secondary Drug Against Refractory or Relapsed Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive lymphoid neoplasm that develops from malignant B-lymphocytes in the outer edge or mantle zone of a lymph node. This is a sub-type of B-cell non-Hodgkin lymphoma characterized by rapid clinical progression and poor response rate to conventional chemotherapeutic drugs with recurrent relapse resulting in a short estimated 5-year overall survival (OS) of 2-5 years depending on the clinical risk. Combination therapies such as R-CHOP, R-DHAP, Hyper-CVAD, VcR-CAP constitute the front-line chemotherapeutic treatment landscape for MCL. Despite good initial response to the combination regimens, all patients develop resistance over time. The Bruton's tyrosine kinase inhibitor (BTKi) Ibrutinib and the proteasome inhibitor (PI) Bortezomib are FDA-approved therapies for refractory or relapsed (R/R) MCL with demonstrated high initial response rate in clinical trials. However, highly variable treatment response along with dose-limiting toxicities has limited the efficacy in real-world settings with the median progression-free survival (PFS) of <15 months and Over-al of 1-2 years.Thus, the identification of novel drugs that function either alone or as combination to curb the oncogenic progression as well as to reduce drug-associated toxicities is of high clinical significance.We have designed a novel optimization-regularization-based computational prediction algorithm called “secDrug” that uses large-scale pharmacogenomics databases like the GDSC1000 to identify novel secondary drugs for the management of treatment-resistant B-cell malignancies. We hypothesize that combination of our predicted secDrugs with BTKi/ PI will be useful in curbing oncogenic progressions of R/R MCL and abrogate drug resistance through simultaneous inhibition of multiple oncogenic factors/pathways. When applied to BTKi/PI-resistant R/R MCL, the top predicted secondary drugs (secDrugs) were YM155 (Survivin inhibitor) and S63845 (selective MCL-1 inhibitor). Interestingly, both Survivin and MCL-1 are reported to be over-expressed in MCL, and their expression is strongly correlated with the oncogenic progression and survivability of the patients.To validate our in-silico predictions, we performed in vitro cytotoxicity assays with the top predicted secDrugs (YM155 and S63845) as single agents (IC50 for YM155 4.87±0.66 nM, for S63845 0.9±1.1 uM) as well as in combination with BTKi/PI against a panel of MCL cell lines representing PI/BTKi sensitive, innate resistant (representing refractory MCL) and clonally-derived acquired resistant (representing relapsed MCL). Our results showed that the YM155 and S63845 exhibited significant synergistic cell killing activities (Combination index/ CI value of 0.31±0.49 as calculated using Chou-Talalay's CI theorem, C.I>1 depicts synergism) alone and in combination with Bortezomib (PI) and Ibrutinib (BTKi), especially in R/R MCL cell lines. Further, our results also showed that both YM155 and S63845 in combination with BTKi/PI were able to significantly lower the effective dose of both BTKi/PI required to achieve desired therapeutic response by >12 times (Dose Reduction Index or DRI for YM155 in combination is 15.87±4.93; DRI for S63845 in combination is 12.34±2.67), thereby making the cell lines relatively more BTKi/PI sensitive. Next, we performed next-generation RNA sequencing analysis to identify mechanisms of secDrug action and synergy. Our Gene expression profiling and Ingenuity pathway analysis of the RNAseq data among YM155-treated MCL cell lines revealed eIF4-p70S6K signaling and mTOR signaling as the top canonical pathways.Our study thus identified YM155 and S63845 as potential novel candidates for repurposing as secondary drugs in combination with BTKi/PI for the treatment of R/R MCL. Currently, we are exploring the probable subclonal molecular mechanisms governing the synergistic drug action by using single-cell transcriptomics analysis. As both YM155 and S63845 have reported activity against cancer stem-ness, we will further investigate the effect of our novel drugs on the cancer stem-like cells in MCL, which have a potential role in treatment resistance.The secDrug algorithm promises to serve as a universal prototype for the discovery of novel drug combination regimens for treatment outcomes in any cancer type by enhancing sensitivity or overcoming resistance to standard of care drugs. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Population monitoring of snow leopards using camera trapping in Naryn State Nature Reserve, Kyrgyzstan, between 2016 and 2019

Four field seasons of snow leopard ( Panthera uncia ) camera trapping inside Naryn State Nature Reserve, Kyrgyzstan, performed thanks to citizen science expeditions, allowed detecting a minimal population of five adults, caught every year with an equilibrated sex ratio (1.5:1) and reproduction: five cubs or subadults have been identified from three litters of two different females. Crossings were observed one to three times a year, in front of most camera traps, and several times a month in front of one of them. Overlap of adults’ minimal territories was observed in front of several camera traps, regardless of their sex. Significant snow leopard presence was detected in the buffer area and at Ulan area which is situated at the reserve border. To avoid poaching on this apex predator and its preys, extending the more stringent protection measures of the core zone to both the Southern buffer area and land adjacent to Ulan is recommended. • Citizen science is a useful tool for monitoring snow leopard ( Panthera uncia ) populations over long periods of time. • Naryn State Nature reserve hosts a breeding population of at least 5 snow leopards with a balanced sex ratio along the study. • Snow leopards territories overlaps regardless of their sex in Naryn State Nature reserve. • Significant snow leopard presence at the edge and buffer zone of the reserve advocates for extending the core reserve limits.

Numerical modeling of magnetic induction in standard and triple Epstein frames considering cutting and staggering of sensor strips

For magnetic energy loss measurements on electric steel sheets, the Epstein tester (ET) is applied for 100 years. However, it suffers from unsolved problems, such as inhomogeneity of flux in the corners and even more of impact of sample cutting. As a matter of fact, a detailed study of flux distributions—as a pre-condition for improvements—has not been performed so far. In this work, we present the results of an advanced numerical 3D-magnetic anisotropic circuit calculation modeling. It considers most relevant impacts such as anisotropy, non-linearity, method of staggering, and in particular, consequences of sample cutting. According to the literature, the latter may yield material deterioration for edge zones of high width WDET. Here, we set WDET to 2.5 mm as a “coarse-cut” convention for practice, and we compare it with perfect “fine-cut” (W = 0). As a main result, deteriorated edge zones of standard ET strips of low width W = 30 mm yield a distinct concentration of flux along inner axial strip regions as a reason for strong local flux inhomogeneity and distortion. Consistent numerical comparisons predict that higher grades of magnetic homogeneity can be expected from wider sample strips, e.g., from a “Triple ET” with W = 90 mm. As a global conclusion, the Epstein frame represents a system of extreme 3D inhomogeneity, especially in the corners. The grade of inhomogeneity reaches its maximum in instants of high permeability. It may be strongly increased through coarse cutting. On the other hand, consequences of cutting can be decreased by increasing the strip width. This would allow for loss measurements using tangential field coils arranged in the central limb regions of TET.

Investigation on theoretical solution of geometric deformation of pressure vessel and pipe subjected to thermo-mechanical loadings

The existing design codes of pressure vessel like the ASME, EN13445 and GB150 only list some calculation formulas of the wall thickness of the cylindrical, spherical or other shells, but not provide the calculation formula of the geometric deformation of these pressure components. Based on the thermo-elastic theory and non-zero axial strain, the exact theoretical formulas of the radial and axial displacements were derived by the four order differential equation of deflection at the edge zone for a cylindrical vessel and a pipe subjected to the thermo-mechanical loadings, respectively. The proposed theoretical solutions were in good agreement with the finite element (FE) numerical solutions. In addition, the influence of edge effect on the geometric deformation of the pressure components was discussed in detail. The calculation formulas developed in this work can be used to precisely calculate the geometrical deformation of the pressure vessel and pipe, which will make the installation process of the pressure system more reliable.

New insights into the development of radiation-induced cardiac damage using a mouse model

Abstract Background The improvement of anticancer-therapy results in a greater amount of long-term survivors after radiotherapy. Therefore, the understanding of cardiotoxicity after irradiation is of increasing importance. Long-term adverse cardiovascular events may become evident years or decades after radiotherapy. The relative contribution of irradiation in relation to other cancer treatments can often only be estimated. Recent experimental and clinical evidence suggests that cardiovascular symptoms, including exertional dyspnoea, may be caused by heart failure with preserved ejection fraction (HFpEF), which remains incompletely understood in patients after radiation therapy. Purpose We aim to characterize the development of radiation-induced cardiomyopathy and elucidate underlying patho-mechanisms. Methods Mice received a single dose of whole thorax irradiation (12.5 Gy) and were sacrificed at 1 and 3 days or 3, 6, 12, 16, 20 and 25–30 weeks. Endothelial cells and immune cells at different time points were quantified using flow cytometry (FACS). Structural changes and localization of endothelial cell damage was imaged using light-sheet fluorescence microscopy (LSFM) with CD31 staining. Development of fibrosis was determined using qRT-PCR (fibronectin and TGFβ), western blot (collagen-1,α-smooth muscle) and (immune-)histological analyses. Functional analyses were conducted using echocardiography and pressure-volume-(PV-)catheterization. Results Endothelial damage was determined by significant reduction of CD31 expression in mouse hearts 6 weeks after irradiation compared to sham-treated control mice using FACS analyses. LSFM showed structural changes especially in the edge zone of left ventricle presented as less densely CD31 stained regions. Additionally, we investigated cardiac immune cell response regarding innate and adaptive immunity, showing specific response to tissue damage at different time points. Invasion of monocytes started 6 weeks after irradiation and highest level of monocytes and macrophages was measured at 12 weeks. Regarding cardiac long-term damage, myocardial fibrosis was detected on RNA- and protein-level as well as in histological analyses with significant changes 20 weeks after chest irradiation. This could be correlated with echocardiographic parameters for diastolic dysfunction (elevated isovolumic relaxation time/mitral valve deceleration time). Also functional reserve of irradiated mice was reduced, investigated by measurement of cardiac output and stroke volume after dobutamine injection in PV-catheterization. Conclusion We described a novel time-dependent endothelial cell damage and immune cell response after thoracic irradiation in mice, which could also be imaged using LSFM. Characterization of long-term damage showed cardiac fibrosis correlating with diastolic dysfunction and reduced contractile reserve. Furthermore, therapeutic approaches will be investigated using the established mouse model. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Dr. S.M. Mrotzek acknowledges the following funding source: IFORES research grant from the Medical Faculty, University Duisburg-Essen, Germany.

Microstructural and Micro-Chemical Evolutions in Irradiated UCO Fuel Kernels of AGR-1 and AGR-2 TRISO Fuel Particles

AGR-1 and AGR-2 tristructural-isotropic (TRISO) fuel particles were fabricated using slightly different fuel kernel chemical compositions, modified fabrication processes, different fuel kernel diameters, and changed 235U enrichments. Extensive microstructural and analytical characterizations were conducted to correlate those differences with the fuel kernels’ responses to neutron irradiations in terms of irradiated fuel microstructure, fission products’ chemical and physical states, and fission gas bubble evolutions. The studies used state-of-the-art transmission electron microscopy (TEM) equipped with energy-dispersive x-ray spectroscopy (EDS) via four silicon solid-state detectors with super sensitivity and rapid speed. The TEM specimens were prepared from selected AGR-1 and AGR-2 irradiated fuel kernels exposed to safety testing after irradiation. The particles were chosen in order to create representative irradiation conditions with fuel burnup in the range of 10.8 to 18.6% fissions per initial metal atom (FIMA) and time-average volume-average temperatures varying from 1070 to 1287°C. The 235U enrichment was 19.74 wt.% and 14.03 wt.% for the AGR-1 and AGR-2 fuel kernels, respectively. The TEM results showed significant microstructural reconstructions in the irradiated fuel kernels from both the AGR-1 and AGR-2 fuels. There are four major phases: fuel matrix of UO2 and UC, U2RuC2, and UMoC2—in the irradiated AGR-2 fuel kernel. Zr and Nd form a solid solution in the UC phase. The UMoC2 phase often features a detectable concentration of Tc. Pd was mainly found to be located in the buffer layer or associated with fission gas bubbles within the UMoC2 phase. EDS maps qualitatively show that rare-earth fission products (Nd et al.) preferentially reside in the UO2 phase. In contrast, in the irradiated AGR-1 fuel kernel, no U2RuC2 or UMoC2 precipitates were positively identified. Instead, there was a high number of rod-shaped precipitates enriched with Ru, Tc, Rh, and Pd observed in the fuel kernel center and edge zone. The differences in irradiated fuel kernel microstructural and micro-chemical evolution when comparing AGR-1 and AGR-2 TRISO fuel particles may result from a combination of irradiation temperature, fuel geometry, and chemical composition. However, irradiation temperature probably plays a more deterministic role. Limited electron energy-loss spectroscopy (EELS) characterizations of the AGR-2 fuel kernel show almost no carbon in the UO2 phase, but a small fraction of oxygen was detected in the UC/UMoC2 phase.

Influence of Roll Diameter on Material Deformation and Properties during Wire Flat Rolling

The influence of roll diameter on the strain distribution, shape change, contact pressure, and damage value of a workpiece was investigated during wire flat rolling to control the material properties of the flattened wire. The flattened wires fabricated by the four different rolls were compared using finite element analysis. The strain inhomogeneity of the flat-rolled wire increased with the roll diameter; thus, the macroscopic shear bands were strengthened as the roll diameter increased during wire flat rolling. The contact width and lateral spreading of the flattened wire increased with the roll diameter; therefore, the reduction in area decreased with the roll diameter. The contour of the normal contact pressure on the wire surface exhibited a similar pattern regardless of the roll diameter. The contact pressure showed higher values at the entry, edge, and exit zones in the contact area. The distribution of the damage value varied with the roll diameter. The free surface region tended to have the peak damage value during the process; however, the center region exhibited the maximum damage value with the roll diameter. From the perspective of the damage value, the optimum roll diameter was in existence during wire flat rolling. The underlying cause of the different strain distributions, shape changes, and damage values of the flat-rolled wire was the different contact lengths originating from the different roll diameters during wire flat rolling.

Diversity and activity rate of a bat communities in a voluntary nature reserve in the Agneby-Tiassa region (South-East, Côte d’Ivoire)

In order to provide basic data on the specific diversity of bats in a private forest of fifty hectares, located in the Agnéby-Tiassa region (South-eastern Côte d&#39;Ivoire), a study was carried out there from August 26 to October 15, 2018. This was conducted in three types of habitats represented by a forest, a wetland and an edge zone. Sixty-three individuals were captured using mist nets during 38 days, from 18h00 to midnight. Twelve species of bats belonging to nine genera and five families have been inventoried. This community is dominated by Epomops buettikoferi, Scotonycteris zenkeri, Nanonycteris veldkampi, Macronycteris gigas, Hipposideros caffer and Mops thersites. The activity study has shown that Microchiroptera are most active from 18h30 to 20h while bats&#39; activity is most intense from 21h30 to 23h00. The forest, the wetland and the edge zone are respectively the most diversified in species of bats. Epomops buettikoferi, Nanonycteris veldkampi and Hipposideros caffer activities are positively correlated with forest and edge zone while Macronycteris gigas, Mops thersites, Scotophilus nux and Eidolon helvum have a greater affinity for the wetland.

Morphological characterization of semi-crystalline POM using nanoindentation

Nanoindentation (NI) is a contact method to investigate localized micromechanical properties of materials, whereby NI of semi-crystalline polymers is challenging. The influence of morphological structures such as spherulites or crystal-lamellae on localized NI depth-force behavior is discussed controversially in literature. Hence, the main objective of this study is to determine the influence of crystalline zones on NI results. Polyoxymethylene (POM) exhibits high crystallinity with the spherulitic structure on the micrometer scale and was therefore chosen to proof the influence of spherulite distribution on NI results concerning modulus. Furthermore, the correspondence between the mean elastic modulus from different NI experiments and macroscopic compression tests will be demonstrated. A POM tensile bar was investigated by NI with a large sphero-conical and a Berkovich indenter tip at different positions of its cross-section. Here, it was found that regions at the edge of the sample have a lower elastic modulus than regions in the middle of the cross-section. This agrees well with polarized light microscopy results, which reveal a skin layer with less crystallinity close to the sample edge. Therefore, the NI measurements in this edge zone result in a lower elastic modulus compared to the more crystalline middle of the cross-section. In summary, semi-crystallinity influences the NI results obtained for POM and the mean of the elastic modulus distribution over the cross-section of the POM sample is in good agreement with macroscopic compression test results.

‘The power to burnish and renew’: porno-accumulation, fascism, and surplus populations in Don DeLillo’s Running Dog

ABSTRACT Don DeLillo’s conspiracy novels Players, Running Dog, and The Names respond to, and imaginatively frame, what Giovanni Arrighi calls the ‘signal crisis’ of US hegemony. Despite mapping the spatio-temporal unfolding of US capital as it financialises accumulation, commodifies visual attention, and imposes neo-colonial economic reforms on ‘underdeveloped’ nations, Marxist critics have dismissed DeLillo’s pastiche thrillers as politically disappointing texts ‘constrained’ by an inability to supply alternative models of reality. In contrast, this article argues that DeLillo’s so-called formal defeats register a ‘discord’ between history and its conceptualisation, an enigma related to their discovery of ‘edge zones of modernity’. Drawing on ideas of historical lateness, the article re-situates DeLillo’s poetics through the optics of uneven and combined development, reflecting on the significance of surplus populations – both for DeLillo’s off-kilter conspiracies but also contemporary Marxist political economy. The article offers a close reading of Running Dog, a porno-political caper in which non-synchronicity manifests itself through the appearance of an object, perhaps the object: an adult film starring Hitler. Running Dog juxtaposes commodity frontiers based on violent appropriation with frontiers of immiseration where labour-power has been exiled from social reproduction altogether. In doing so, DeLillo refunctions romance into a genre of secular stagnation.

Monitoring the mode of action of synthetic and natural biocides against Aeromonas hydrophila by Raman spectroscopy and chemometrics

We have investigated the mode of action of synthetic biocides, (2-(thiocyanomethylthio) benzothiazole(TCMTB), dichlorophen, (commonly used in leather industry for preservation) and natural biocides, oregano and eucalyptus oils, on Aeromonas hydrophila using Raman spectroscopy in collaboration with multivariate analysis and 2D correlation spectroscopy to evaluate whether Raman spectra acquired contained valuable information to study the action of biocides on bacterial cells. The growth of A. hydrophila in clear and outer edge zone of inhibition differ in their reaction with different biocides, which allows us to highlight the differences as a characteristic of two kinds of bacteria. Such classification helps identify oregano oil as the most effective biocide by altering clear and outer edge zone of bacteria. Standard disk diffusion assay method was used for screening biocide bacteria interactions and later analysed by Raman spectroscopy. The paper also presents the introduction of TCMTB and oregano oil into leather processing stages to examine and determine the antimicrobial effect as an application to real-world setting. Therefore, we conclude that Raman spectroscopy with appropriate computational tools constitutes a powerful approach for screening biocides, which provide solutions to all the industries using biocides including leather industry, considering the potentially harmful effect of biocides to humans and the environment.Graphical abstract

Riparian Zone Nitrogen Management through the Development of the Riparian Ecosystem Management Model (REMM) in a Formerly Glaciated Watershed of the US Northeast

The Riparian Ecosystem Management Model (REMM) was developed, calibrated and validated for both hydrologic and water quality data for eight riparian buffers located in a formerly glaciated watershed (upper Pawcatuck River Watershed, Rhode Island) of the US Northeast. The Annualized AGricultural Non-Point Source model (AnnAGNPS) was used to predict the runoff and sediment loading to the riparian buffer. Overall, results showed REMM simulated water table depths (WTDs) and groundwater NO3-N concentrations at the stream edge (Zone 1) in good agreement with measured values. The model evaluation statistics showed that, hydrologically REMM performed better for site 1, site 4, and site 8 among the eight buffers, whereas REMM simulated better groundwater NO3-N concentrations in the case of site 1, site 5, and site 7 when compared to the other five sites. The interquartile range of mean absolute error for WTDs was 3.5 cm for both the calibration and validation periods. In the case of NO3-N concentrations prediction, the interquartile range of the root mean square error was 0.25 mg/L and 0.69 mg/L for the calibration and validation periods, respectively, whereas the interquartile range of d for NO3-N concentrations was 0.20 and 0.48 for the calibration and validation period, respectively. Moreover, REMM estimation of % N-removal from Zone 3 to Zone 1 was 19.7%, and 19.8% of N against actual measured 19.1%, and 26.6% of N at site 7 and site 8, respectively. The sensitivity analyses showed that changes in the volumetric water content between field capacity and saturation (soil porosity) were driving water table and denitrification.

Consideration of the mechanical damage behavior of rock salt during calculation of infiltration-cracks in the edge zone of gas storage caverns

Underground storage in salt caverns is a preferred method for the intermediate storage of natural gas to cover seasonal fluctuation in consumption and commercial gas storage. The prove of the stability and tightness of the storage required for safe operation is continuously adapted to the current state of the art. For many years, an intensive scientific investigation has been carried out within the frame-work of repository research with continuous optimization of the rock mechanical modelling of the material behavior of rock salt. From the elaboration of the research results on the pressure-driven infiltration processes into the primarily non-permeable salt rock, it emerges that during gas storage operation, in addition to the areal infiltration, the formation of macroscopic infiltration-cracks in the cavern surrounding salt rock is to be expected as well. This thesis deals with the computational simulation of macroscopic infiltration-cracks within the scope of theoretical modelling of salt cavern behavior during gas storage, taking into account additional mechanical damage processes in the rock salt. On the basis of variational calculus, the infiltration fracture propagation will be evaluated, considering different model approaches in material behavior of the cavern surrounding rock salt mass. As a result of the present work, it should be noted that with regard to the propagation of infiltration-cracks in gas caverns, constitutive model approaches for the description of the mechanical damage and healing behavior of rock salt can be neglected for a conservative assessment.

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

AbstractThe expansion of oil palm monocultures into globally important Southeast Asian tropical peatlands has caused severe environmental damage. Despite much of the current focus of environmental impacts being directed at industrial scale plantations, over half of oil palm land‐use cover in Southeast Asia is from smallholder plantations. We differentiated a first generation smallholder oil palm monoculture into 8 different sampling zones, and further divided the 8 sampling zones into oil palm root influenced (Proximal) and reduced root influence (Distal) areas, to assess how peat properties regulate in situ carbon dioxide (CO2) and methane (CH4) fluxes. We found that all the physico‐chemical properties and nutrient concentrations except sulphur varied significantly among sampling zones. All physico‐chemical properties except electrical conductivity, and all nutrient content except nitrogen and potassium varied significantly between Proximal and Distal areas. Mean CO2 fluxes (ranged between 382 and 1191 mg m−2 h−1) varied significantly among sampling zones, and between Proximal and Distal areas, with notably high emissions in Dead Wood and Path zones, and consistently higher emissions in Proximal areas compared to Distal areas within almost all the zones. CH4 fluxes (ranged between −32 and 243 µg m−2 h−1) did not significantly vary between Proximal and Distal areas, however significantly varied amongst sampling zones. CH4 flux was notably high in Canal Edge and Understorey Ferns zones, and negative in Dead Wood zone. The results demonstrate the high heterogeneity of peat properties within oil palm monoculture, strengthening the need for intensive sampling to characterize a land use in the tropical peatlands.

Interference Mitigation and Power Minimization in 5G Heterogeneous Networks

Macro cells’ (MCs) densification with small cells (SCs) is one of the promising solutions to cope with the increasing demand for higher data rates in 5G heterogeneous networks (HetNets). Unfortunately, the interference that arises between these densely deployed SCs and their elevated power consumption have caused huge problems facing the 5G HetNets. In this paper, a new soft frequency reuse (SFR) scheme is proposed to minimize the interference and elevate the network throughput. The proposed scheme is based on on/off switching the SCs according to their interference contribution rate (ICR) values. It solves the interference problem of the densely deployed SCs by dividing the cell region into center and edge zones. Moreover, SCs on/off switching tackles the elevated power consumption problem and enhances the power efficiency of the 5G network. Furthermore, our paper tackles the irregular nature problem of 5G HetNets and compares between two different proposed shapes for the center zone of the SC: circular, and irregular shapes. Additionally, the optimum radius of the center zone, which maximizes the total system data rate, is obtained. The results show that the proposed scheme surpasses the traffic and the random on/off switching schemes, as it decreases the outage probability and enhances the total system data rate and power efficiency. Moreover, the results demonstrate the close performance of both the irregular and circular shapes for the center zone.

The in-situ β phase reinforced Ti/Zr-based bulk metallic glass matrix composite by selective laser melting

In this study, in-situ β phase reinforced Ti/Zr-based BMGCs without toxic element Be, (Ti0.65Zr0.35-yNby)100-xCux (x = 5, 10, y = 0.05, 0.1, at. %), were prepared via selective laser melting (SLM). The effect of Cu and Nb contents on phase formation, microstructure, and compressive mechanical properties were studied, and the microcrack formation mechanism in the deposits with lower Cu content (5 at. %) was also investigated. With the increase of Cu content from 5 to 10 at. %, the volume fraction of β phase decreased, while the volume fraction of amorphous phase and (Ti, Zr)2Cu phase increased. Meanwhile, the amorphous phase presented a more continuous network-shaped morphology. Compared with the content of Cu element, the variation of Nb content had a minor effect on the phase precipitation and microstructure evolution. With the increase of Nb content, β phase became more stable, which may cause the increase of compression fracture strain. In addition, the microstructure with a good connectivity of β phase in the center zone of the molten pool had a higher deformation capacity than that in the edge zone of molten pool, where β phase was isolated by the amorphous phase network. There are some solidification microcracks existing in Cu5Nb4.75 and Cu5Nb9.5 deposits. Because of a higher |dT/d(fS1/2)| near fS1/2 = 1, the liquid phase cannot feed the liquid channel between β phases in time, liquid film is ruptured, and solidification crack forms.

Fire enhances forest degradation within forest edge zones in Africa

Fire enhances forest degradation within forest edge zones in Africa

Lateral behavior of wood frame shear walls sheathed with densified plywood under monotonic loading

Modern construction projects such as high-rise buildings require increasingly lighter and stronger wood frame shear walls. The stress level of the edge zone in the sheathing panel is generally larger than that of the middle zone under lateral loading, and the mechanical properties of wood-based panels are positively related with density. A series of fast-growing poplar plywood with a marginal or overall densification were prepared in this study for use as wood shear wall sheathing panels. The plywood density was controlled to 550, 550 (edge, 650), 550 (edge, 840), and 650 kg⋅m−3, then full-scaled walls sheathed with the samples were monotonically loaded and compared against a wall sheathed with 12 mm OSB to determine the effects of densification. The elastic lateral stiffness of the densified plywood sheathing wall with marginal density of 650 and 840 kg⋅m−3, relative to 550 kg⋅m−3, increased by 39.8% and 47.8% as the ultimate bearing capacity was increased by 15.5% and 37%, which is better than the commonly-used OSB sheathing wall accompanied by slightly lower ductility. The lateral behavior of the plywood sheathing wall appears to increase as density increases. The marginal-densified plywood can substitute for overall densified material as it presents nearly identical lateral behavior when used as a wood shear wall sheathing panel. The wall with marginal density of 840 kg⋅m−3 showed the best overall lateral performance in this experiment. Relative error was controlled within 10% using the rheological model proposed by Casagrande to theoretically verify the lateral bearing capacity and lateral displacement of the test wall.

Influence of Turn-Rolling on the Residual Stresses and Microstructure of C45E and the Effects on Fatigue Life under Cyclic Loading

Abstract The microstructure and the residual stress state have a significant influence on the service life of the component. The deep rolling process already enables a significant increase in the strength and service life of highly stressed components. By using the hybrid manufacturing process of turn rolling, the edge zone properties can be influenced to such an extent that the service life is further increased compared to conventional deep rolling. In addition to a change in the residual stress state, the use of the turning process temperature also leads to a significant grain refinement in the edge zone area, which has a positive effect on the component service life. This modification of the edge zone can be significantly influenced by the machining speed.