bluuebunny/crossref_metadata_2025 huggingface dataset:
Coastal Wetlands Play an Important Role in the Ecological Security Pattern of the Coastal Zone
Authors: Yang Qingchuan , He Congying , Xu Yuankai , Ye Yunqi , Guo Hong , Zhang Shu , Li Fan , Liu Kui
Published: December 2022

The construction of an ecological security pattern can effectively overcome the contradiction between regional human exploitation and ecological protection in the coastal zone. Taking the Xiangshan Bay (XSB) basin as an example, this study identified ecological source areas from three aspects, namely ecosystem services’ importance, ecological sensitivity, and landscape connectivity, and then constructed ecological resistance surfaces, identified ecological corridors, and constructed an ecological security pattern. The results show that the natural reserves in the XSB basin were all located in the identified primary ecological source areas, thus indicating the feasibility and reliability of the “importance–connectivity–sensitivity” ecological source identification mechanism in this study. The ecological corridor in the coastal wetland area accounts for about 40% of the total corridor length, which is the link connecting other ecological sources, revealing the important role of coastal wetlands in the coastal ecosystem. Through the ecological security pattern of the XSB basin and field investigation, we put forward suggestions such as clearing Spartina alterniflora, restoring salt marsh wetland vegetation, and strengthening follow-up monitoring for the restoration of coastal wetlands. This study is expected to provide reference and guidance for the improvement of coastal zone ecological protection and restoration.
Inconsistencies in Cadastral Boundary Data—Digitisation and Maintenance
Authors: Fetai Bujar , Tekavec Jernej , Fras Mojca Kosmatin , Lisec Anka
Published: December 2022

Most cadastral systems today are coordinate-based and contain only a weak or no reference to measurements or the origin of the information. In some contexts, this is largely due to the transition of land data management and maintenance from an analogue to a digital environment. This study focuses on analysing the importance of the measurement-based cadastre and the digitisation process in North Macedonia and Slovenia. The survey-based boundary data and their integration into the digital environment were not considered in either case study. The positional differences between the survey-based boundary coordinates and the graphical coordinates of the boundaries are significant. The RMSE(2D) for Trebosh was 48 cm, and the RMSE(2D) for Ivanjševci was 56 cm. Consequently, the differences in location affected the areas of the cadastral parcels, resulting in an RMSE of 26 m2 and 23 m2 for Trebosh and Ivanjševci, respectively. These differences can be considered as differences within the cadastral boundary data. Therefore, before harmonising the data between the cadastre and the land register, the inconsistencies within the cadastral data should be eliminated first. The differences in the location of cadastral boundaries and parcel area create new challenges in cadastral procedures (formatting of parcels), conflicts in the relocation of boundaries, and impacts on the land market. The solution lies in the way data is maintained, avoiding duplication of attributes or eliminating inconsistencies (after duplication). Both solutions require further modifications of the legal framework for cadastral procedures related to boundary adjustments and data compliance. This study provides a basis for evaluating inconsistencies in cadastral data and highlights the importance of proper source data selection in the digitization process.
Mobilizing the Midstream for Supporting Smallholder Intensification
Authors: Ruben Ruerd , Kuijpers Rob , Dijkxhoorn Youri
Published: December 2022

Most policies and incentives that aim to enable smallholder farmers towards the intensification of their agri-food production systems focus on supply-side strategies, such as training, technical assistance or credit services. Far less attention is usually given to demand-side drivers, such as the role of midstream value chain actors supporting smallholder’s investments in primary production. This explorative paper provides new insights on the value addition in the production vs. the midstream segments of agri-food value chains. It focusses attention on the influence of value chain integration on smallholders’ production and investment opportunities, and the implications for the structure of primary production. We use data from several value chains in sub-Saharan Africa to illustrate how farmers link to commercial midstream actors are able to enhance resource productivity, efficiency and profitability. In addition, we show that a larger role of the midstream in value added creation is associated with a more equal farm size distribution.
Responses of Phragmites australis to Nitrogen Addition along Salinity Gradients in Coastal Saline–Alkali Soil
Authors: Gong Huarui , Han Yanyun , Li Jing , Liu Zhen , Hou Ruixing , Zhang Yitao , Dou Wenjun , Wang Bing , Ouyang Zhu
Published: December 2022

Soil salinization and nitrogen (N) enrichment in saline–alkali soils resulting from human activities cause potential environmental pressure on Phragmites australis. However, the response of P. australis to N addition under different salt conditions remains unknown. This study examined the changes in soil properties and growth indices as well as their relationship to N addition through an in situ field experiment using three soil salinity levels with P. australis in the Yellow River Delta. The study showed that soil salinity levels significantly affected the effects of N addition on soil pH and water contents. N addition increased the soil NO3– contents and decreased soil available phosphorus (Avail. P) contents; however, soil salinity levels did not impact the effects of N addition on soil NO3− and Avail. P contents. N addition decreased the biomass of P. australis, since the decrease in the competitiveness for N sources changed the vegetation diversity. The results suggest that the biomass, plant height, and leaf soil plant analysis development (SPAD) values of P. australis increased with increasing soil Avail. P contents rather than soil NO3– contents. Therefore, we suggest the important role of Avail. P addition in N enrichment conditions in saline–alkali wasteland and estuarine wetland ecosystems.
Spatial Nature and Geographical Characteristics of Drug Crime in Hungary
Authors: Mátyás Szabolcs , Nyitrai Endre
Published: December 2022

Relatively few people in Hungary deal with the investigation of the spatial nature of crime. In connection with drug crime, we rarely find research dealing with this topic. The study shows why it is difficult to examine the spatiality of various drug-related crimes. It describes the main spatial trends of crime and the presence of criminal organizations in the field of drug trafficking by analyzing the criminal statistics data of the past decades. Political and drug policy changes, as well as the activities of criminal organizations at the international level, are usually hidden behind the spatial changes. In all cases, these also have a significant impact on the spatial distribution of drug use. The present research is primarily looking to answer whether there is a connection between the main focal points of organized crime and the centers of drug crime.
Periodontal and Orthodontic Synergy in the Management of Stage IV Periodontitis: Challenges, Indications and Limits
Authors: Garbo Daniela , Aimetti Mario , Bongiovanni Loretta , Vidotto Cristina , Mariani Giulia Maria , Baima Giacomo , Romano Federica
Published: December 2022

This retrospective study described the clinical and radiographic long-term outcomes of combined periodontal and orthodontic treatment (OT) with fixed appliances in patients with Stage IV periodontitis and pathologic tooth migration (PTM) in the anterior sextants. OT was performed in either one or both arches, using tooth-supported or skeletal anchorage, following completion of active periodontal treatment and accurate planning of tooth movement biomechanics. Twenty-nine patients were identified and retrospectively examined when presenting for a supportive periodontal care (SPC) appointment. The mean SPC duration was 8.9 years (range 5 to 12 years). All anterior-migrated teeth showed statistically significant periodontal improvement compared to baseline values and stable radiographic bone levels at the final follow-up. Residual probing depths were 2.9 ± 0.5 mm at the end of active periodontal treatment, and they remained stable at the completion of OT (2.9 ± 0.6 mm) and at the last follow-up visit (2.8 ± 0.5 mm). These findings suggest that OT is a safe and effective treatment in improving the long-term prognosis of teeth with PTM in Stage IV periodontitis provided that periodontal health has been re-established and maintained with individualized SPC sessions.
Prosthetic Joint Infection in Mega-Arthroplasty Following Shoulder, Hip and Knee Malignancy—A Prospective Follow-Up Study
Authors: Khakzad Thilo , Karczewski Daniel , Thielscher Leonard , Reiter Konstantin , Wittenberg Silvan , Paksoy Alp , Flörcken Anne , Rau Daniel , Märdian Sven
Published: December 2022

Introduction: The risk of prosthetic joint infection (PJI) in mega-prosthesis for malignancy is increased compared with non-tumor cases. While several studies describe PJI in tumor-related arthroplasty, prospective studies comparing infection characteristics among different joints are limited. The present study analyzes mega-arthroplasty for hip, knee, and shoulder malignancy and compares the epidemiology, diagnosis, microbe spectrum, treatments, and outcomes between the different entities. Methods: The retrospective inclusion criteria were as follows: (1) mega-arthroplasty (2) in the hip, knee, or shoulder joint and a total femur arthroplasty (3) following a malignant bone tumor or metastasis (4) between 1996 and 2019. All included patients were prospectively followed and invited for a renewed hospital examination, and their PJI characteristics (if identified) were analyzed using both retrospective as well as newly gained prospective data. A PJI was defined according to the Infectious Disease Society of America (IDSA) and re-infection was defined according to the modified Delphi Consensus criteria. Results: In total, 83 cases of tumor mega-arthroplasty at a mean follow-up of 3.9 years could be included (32 knee, 30 hip, and 19 shoulder cases and 2 cases of total femur arthroplasty). In total, 14 PJIs were identified, with chondrosarcoma in 6 and osteosarcoma in 3 being the leading tumor entities. Knee arthroplasty demonstrated a significantly higher rate of PJI (p = 0.027) compared with hips (28.1% vs. 6.7%), while no significant difference could be found between the knee and shoulder (10.5%) (p = 0.134) or among shoulder and hip cases (p = 0.631). The average time of PJI following primary implantation was 141.4 months in knee patients, 64.6 in hip patients, and 8.2 months in shoulder patients. Age at the time of the primary PJI, as well as the time of the first PJI, did not show significant differences among the groups. Thirteen of the fourteen patients with PJI had a primary bone tumor. Statistical analysis showed a significant difference in the disadvantage of primary bone tumors (p = 0.11). While the overall cancer-related mortality in the knee PJI group (10%) was low, it was 50% in the hip and 100% in the shoulder group. Conclusion: The risk of PJI in knee tumor arthroplasty is significantly increased compared with hips, while cancer-related mortality is significantly higher in hip PJI cases. At the same time, mega-prostheses appear to be associated with a higher risk of infection due to a primary bone tumor compared with metastases. The study confirms existing knowledge concerning PJI in tumor arthroplasty, while, being one of the few studies to compare three different joints concerning PJI characteristics.
Understanding the Dynamics of the Structural States of Cannabinoid Receptors and the Role of Different Modulators
Authors: Manandhar Anjela , Haron Mona H. , Klein Michael L. , Elokely Khaled
Published: December 2022

The cannabinoid receptors CB1R and CB2R are members of the G protein-coupled receptor (GPCR) family. These receptors have recently come to light as possible therapeutic targets for conditions affecting the central nervous system. However, because CB1R is known to have psychoactive side effects, its potential as a drug target is constrained. Therefore, targeting CB2R has become the primary focus of recent research. Using various molecular modeling studies, we analyzed the active, inactive, and intermediate states of both CBRs in this study. We conducted in-depth research on the binding properties of various groups of cannabinoid modulators, including agonists, antagonists, and inverse agonists, with all of the different conformational states of the CBRs. The binding effects of these modulators were studied on various CB structural features, including the movement of the transmembrane helices, the volume of the binding cavity, the internal fluids, and the important GPCR properties. Then, using in vitro experiments and computational modeling, we investigated how vitamin E functions as a lipid modulator to influence THC binding. This comparative examination of modulator binding to CBRs provides significant insight into the mechanisms of structural alterations and ligand affinity, which can directly help in the rational design of selective modulators that target either CB1R or CB2R.
Understanding the Influences of Multiscale Waviness on the Elastohydrodynamic Lubrication Performance, Part I: The Full-Film Condition
Authors: Wang Yuechang , Li Changlin , Du Jianjun , Morina Ardian
Published: December 2022

Understanding the responses of tribosystems to multiscale roughness is fundamental for the identification of the relevant roughness scales. This work used a point-contact elastohydrodynamic lubrication (EHL) problem as a representative tribosystem and artificially generated waviness with different amplitudes, frequencies, and directions to mimic the multiscale roughness. The amplitudes and frequencies are related to the feature geometry of smooth EHL problems. This work consists of Part I (this paper), focusing on the full-film condition, and Part II, focusing on the partial-film condition. Generated waviness is input to a transient thermal EHL model. The simulation is conducted 1600 times for different waviness parameters, loads, and speeds. Seven performance parameters are extracted: the minimum film thickness, maximum pressure, central film thickness, central pressure, mean film thickness, coefficient of friction (COF), and maximum temperature rise. The ratios of these parameters with and without waviness are plotted on the frequency–amplitude coordinate plane as contour maps. The influences of the amplitude, frequency, wave direction, load, and speed on the seven performance parameters are analyzed and summarized. The simulated data and plotted contour maps are provided to the readers in the Supplementary Material.
Application of Integrated BWM Fuzzy-MARCOS Approach for Coating Material Selection in Tooling Industries
Authors: Kumar Sunil , Bhaumik Shubrajit , Patnaik Lokeswar , Maity Saikat Ranjan , Paleu Viorel
Published: December 2022

The life of metal forming dies and the efficiency of tooling industries depends on the mechanical and wear properties of tool steel. These properties can be further improved by depositing the ceramic coating on heat-treated tool steel. Numerous coating materials with various excellent features are already available commercially; however, the selection of the best coating material is still an immense challenge for users. Compared to various studies related to material selection problems in the contrasting area of utilization, remarkably, little research work has been done in tooling industries. In the present work, we have identified eight coating materials (alternatives) and nine evaluation criteria under the consultation of an expert in the tooling application and tribological field. To deal with this coating material selection problem, an integrated fuzzy-multi attributed decision-making method is proposed which comprises best worst method and fuzzy-Measurement Alternatives and Ranking according to the Compromise Solution method. This integrated fuzzy- multi attributed decision-making method is used to evaluate the alternatives, and the obtained results were scrutinized via utilizing various sensitivity analysis procedures. In the first phase of analysis, seven scenarios of criteria weight change were used, which was derived by the best-worst method; dynamic matrices are used in the second phase of analysis. In the third and fourth phases, obtained ranks were compared with those obtained by different weight calculation methods and ranking methods, respectively. In the present study, AlCrN/TiAlN coating (alternative Cm5) was found to be the best coating material based on the results obtained after sensitivity analysis. Further, in this study, we have proposed a novel method that helps to solve the coating material selection problem or any kind of selection complications.
Aging Interfacial Structure and Abnormal Tensile Strength of SnAg3Cu0.5/Cu Solder Joints
Authors: Chen Dongdong , Qin Junhu , Zhang Xin , Liang Dongcheng , Bai Hailong , Yi Jianhong , Yan Jikang
Published: December 2022

In this study, the interfacial structure and abnormal long-term increase of tensile strength in the interfacial intermetallic compounds (IMCs) between SnAg3Cu0.5 solder and Cu substrates during isothermal aging were investigated. After reflow soldering, the IMC layer at the interface was thin and scallop-type. The interfacial layer became thicker with the increase in aging time. After 200 h of aging at 150 °C, the thickness of the interface gradually increased to 3.93 μm and the interface became smooth. Compared with the unaged Cu-Sn interface, the aged joint interface contained more Cu3Sn. The top of the IMC being reflown was relatively smooth, but became denser and prismatic in shape after 200 h of aging at 150 °C. The tensile strength of the joint, immediately after the reflow, reached 81.93 MPa. The tensile properties of the solder joints weakened and then strengthened as they aged. After 200 h of aging at 150 °C, the tensile strength was 83.86 MPa, which exceeded that of the unaged solder joint interface, because the fracture mode of the solder joints changed during aging.
Effective Attenuation of Electromagnetic Waves by Synergetic Effect of α-Fe2O3 and MWCNT/Graphene in LDPE-Based Composites for EMI Applications
Authors: Manjappa Praveen , Rajan Hari Krishna , Mahesh Mamatha Gowdaru , Sadananda Karthikeya Gulur , Channegowda Manjunatha , Shivashankar Girish Kumar , Mutt Nagabhushana Bhangi
Published: December 2022

In this study, a polymer nanocomposite is synthesized using magnetic and conducting fillers for enhanced electromagnetic interference (EMI) shielding. Alfa-ferrite (α-Fe2O3) nanoparticles with minimal multiwalled carbon nanotube (MWCNT) as low as 5 weight % in combination with variable concentrations of graphene nanoplatelets (GNP) are used as fillers in low-density polyethylene (LDPE) polymer matrix. Nanofillers and the polymer matrix are characterized by various techniques such as XRD, SEM, color mapping, EDAX, TGA, etc. The EMI shielding efficiency of the LDPE-based nanocomposites is tested using Vector Network Analyzer (VNA). The results showed that composite with LDPE:MWCNT:GNP:α-FO-50:5:40:5 displayed enhanced EMI shielding (in X-band (8.2–12.4 GHz) compared to other concentrations studied. This is due to the superior ohmic, dielectric, and magnetic losses at this particular composition and to the synergism amongst the filler. An attenuation of 99.99% was achieved for 5% α-Fe2O3. The mechanistic aspects of the shielding are discussed using permittivity, conductivity, and attenuation.
Effect of Ordinary Portland Cement on Mechanical Properties and Microstructures of Metakaolin-Based Geopolymers
Authors: Gao Renhui , Yang Wei , Duan Zhenhua , Liu Hui , Deng Qi , Hua Minqi
Published: December 2022

Geopolymers have been considered a sustainable alternative to ordinary Portland cement (CEM I) for its lower embodied carbon and ability to make use of industrial by-products. Additionally, its excellent engineering properties of high strength, low permeability, good chemical resistance, and excellent fire resistance also strike a chord in the minds of researchers. The goal of this study is to clarify the effect of calcium sources on the mechanical properties and microstructures of the geopolymers. CEM I was chosen as the sole calcium source, while metakaolin was used as the source material. Five distinct geopolymers were prepared, having various ratio of CEM I: 0%, 5%, 10%, 20%, and 30%. The alkali-activator was a mixture of 12 M sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), utilizing compressive strength and flexural strength to evaluate the changes of the geopolymers’ mechanical properties. SEM, XRD, and FTIR were used to examine microscopic features, evaluate internal morphology, and analyze changes in components of the geopolymers containing different amounts of CEM I. The experimental results indicated that the optimal incorporation of CEM I was 5%. Under this dosage, the compressive strength and flexural strength of the geopolymers can reach 71.1 MPa and 6.75 MPa, respectively. With the incorporation of CEM I, the heat released by cement hydration can accelerate the geopolymerization reaction between silica-alumina materials and alkaline solutions. Additionally, the coexistence of N-A-S-H gel from components of an aluminosilicate mix and C-S-H gel from the CEM I promoted a more densified microstructure of the geopolymers and improved the geopolymer’s strength. However, as the amount of CEM I in the mixture increased, the geopolymer matrix was unable to provide enough water for the CEM I to hydrate, which prevented excessive CEM I from forming hydration products, weakening the workability of the matrix and eventually hindering the development of geopolymer strength.
Thermodynamic Analysis of Anomalous Shape of Stress–Strain Curves for Shape Memory Alloys
Authors: Beke Dezső L. , Kamel Sarah M. , Daróczi Lajos , Tóth László Z.
Published: December 2022

In some shape-memory single crystals the stress–strain (σ~ε) curves, belonging to stress induced martensitic transformations from austenite to martensite at fixed temperature, instead of being the usual slightly increasing function or horizontal, have an overall negative slope with sudden stress drops in it. We discuss this phenomenon by using a local equilibrium thermodynamic approach and analysing the sign of the second derivative of the difference of the Gibbs free energy. We show that, considering also the possible nucleation and growth of two martensite structural modifications/variants, the stress–strain loops can be unstable. This means that the overall slope of the uploading branch of the stress–strain curve can be negative for smooth transformation if the second martensite, which is more stable with larger transformation strain, is the final product. We also show that local stress-drops on the stress–strain curve can appear if the nucleation of the second martensite is difficult, and the presence of such local stress-drops alone can also result in an overall negative slope of the stress–strain curves. It is illustrated that the increase of the temperature of the thermal recovery during burst-like transition is a measure of the change of the nucleation energy: the more stable martensite has larger nucleation energy.
The Mechanical Behavior and Enhancement Mechanism of Short Carbon Fiber Reinforced AFS Interface
Authors: Yan Chang , Cai Jiaxu , Xiang Kun , Zhao Jinfeng , Lei Wanqing , Fang Changqing
Published: December 2022

The aluminum foam sandwich (AFS), which perfectly combines the excellent merits of an aluminum foam core and face sheet materials, has extensive and reliable applications in many fields, such as aerospace, military equipment, transportation, and so on. Adhesive bonding is one of the most widely used methods to produce AFS due to its general applicability, simple process, and low cost, however, the bonding interface is known as the weak link and may cause a serious accident. To overcome the shortcomings of a bonded AFS interface, short carbon fiber as a reinforcement phase was introduced to epoxy resin to reinforce the interface adhesion strength of AFS. Single lap shear tests and three-point bending tests were conducted to study the mechanical behavior of the reinforced interface and AFS, respectively. The failure mechanism was studied through a macro- and microanalysis. The result showed that after the reinforcement of carbon fiber, the tangential shear strength of the interface increased by 73.65%. The effective displacement of AFS prepared by the reinforced epoxy resin is 125.95% more than the AFS prepared by the unreinforced epoxy resin. The flexure behavior of the reinforced AFS can be compared with AFS made through a metallurgical method. Three categories of reinforcement mechanisms were discovered: (a) the pull off and pull mechanism: when the modified carbon fiber performed as the bridge, the bonding strength improved because of the pull off and pull out of fibers; (b) adhesion effect: the carbon fiber gathered in the hole edge resulted in epoxy resins being gathered in there too, which increased the effective bonding area of the interface; (c) mechanical self-locking effect: the carbon fiber enhanced the adhesive filling performance of aluminum foam holes, which improved the mechanical self-locking effect of the bonding interface.
Properties of Cold Sprayed Titanium and Titanium Alloy Coatings after Laser Surface Treatment
Authors: Zybała Rafał , Bucholc Bartosz , Kaszyca Kamil , Kowiorski Krystian , Soboń Dominika , Żórawski Wojciech , Moszczyńska Dorota , Molak Rafał , Pakieła Zbigniew
Published: December 2022

Additive manufacturing (AM) has seen remarkable development in recent years due to relatively high efficiency of the process. Cold spraying (CS) is a particular method of AM, in which titanium and titanium alloy powders are used. CS is a very competitive technology enabling the deposition of coatings, repairing machine parts, and manufacturing new components. For specific applications, the surface of cold-sprayed materials may require further processing. This paper reports an attempt to employ laser surface treatment (LST) of cold-sprayed coatings on an aluminium alloy substrate. The influence of laser beam interaction time on the coatings’ properties was analysed. The microstructure was investigated and observed employing scanning electron microscopy (SEM). To evaluate residual stress after CS and LST, the sin2ψ technique was used. Investigations were also performed on Vickers hardness, contact angle, and surface roughness. Significant changes in the surface morphology of the coatings and elevated residual stress levels dependent on the laser beam interaction time were observed. Increased Vickers hardness was recorded for titanium alloy Ti6Al4V. LST also led to increased surface hydrophilicity of the modified materials Ti and Ti6Al4V.
Mechanical Performance of Flax Fiber Composites with Waste Glass Fibers as a Core Structure
Authors: Pisupati Anurag , Deléglise Lagardère Myléne
Published: December 2022

This work sheds light on the first steps towards using glass fiber waste for semi-structural applications. This work aims to improve the properties of random flax fiber composites by incorporating waste glass fibers (WGF) obtained from the fiber production line. The waste glass fibers were incorporated as a core structure between the flax layers to form a hybrid composite. Two routes of manufacturing viz. vacuum infusion and autoclave were used to identify the optimum route to incorporate the WGF in flax fiber composites. The quality of composites was investigated in terms of residual void content and thickness uniformity. Residual void content was identified to be directly proportional to the WGF content in the composites. With the increase in WGF content, the flexural and impact properties were increased by 47% and 117%, respectively, indicating a positive hybridization effect. Furthermore, a global warming potential indicator was identified to be small, indicating the eco-friendliness of these composites.
Effect of Intercritical Temperature on the Microstructure and Mechanical Properties of a Ferritic–Martensitic Dual-Phase Low-Alloy Steel with Varying Nickel Content
Authors: Rodoni Esteban , Verbeken Kim , Depover Tom , Iannuzzi Mariano
Published: December 2022

Dual-phase low-alloy steels combine a soft ferrite phase with a hard martensite phase to create desirable properties in terms of strength and ductility. Nickel additions to dual-phase low-alloy steels can increase the yield strength further and lower the transformation temperatures, allowing for microstructure refining. Determining the correct intercritical annealing temperature as a function of nickel content is paramount, as it defines the microstructure ratio between ferrite and martensite. Likewise, quantifying the influence of nickel on the intercritical temperature and its synergistic effect with the microstructure ratio on mechanical properties is vital to designing dual-phase steels suitable for corrosive oil and gas services as well as hydrogen transport and storage applications. In this work, we used a microstructural design to develop intercritical annealing heat treatments to obtain dual-phase ferritic–martensitic low-alloy steels. The intercritical annealing and tempering temperatures and times were targeted to achieve three different martensite volume fractions as a function of nickel content, with a nominal content varying between 0, 1, and 3-wt% Ni. Mechanical properties were characterized using tensile testing and microhardness measurements. Additionally, the microstructure was studied using scanning electron microscopy coupled with electron backscatter diffraction analysis. Tensile strength increased with increasing martensite ratio and nickel content, with a further grain refinement effect found in the 3-wt% Ni steel. The optimal heat treatment parameters for oil and gas and hydrogen transport applications are discussed.
Tensile Stresses in the Coating with Interlayer under Normal and Tangential Loading
Authors: Bajkowski Adam Stanisław , Grądzki Rafał , Gargasas Justinas , Bazienė Kristina
Published: December 2022

In this paper, we obtained the analytic solution of the three-dimensional problem of elasticity concerning non-homogeneous half-space, in which the surface is under normal and tangential loading applied in a circular area. Half-space is composed of the homogeneous body, as well as coatings containing two homogeneous layers: interlayer and top layer. The analysis was carried out in cases where the Young’s modulus of the intermediate layer differed from the Young’s modulus of the substrate and the top layer. We have concentrated on first principal stress analysis. The obtained results can serve as an indication for the design of the composition of coatings in the context of tensile stress.
Relation between Mechanical Hardening and Nitrogen Profile of PBII Nitrided Titanium Alloy
Authors: Parry Valérie , Le Bourhis Eric , Pichon Luc , Drouet Michel
Published: December 2022

Surface treatments of Ti-6Al-4V alloys are of utmost importance for biomedical applications since they allow for tribological gain. Here, Ti-6Al-4V disks have been PBII nitrided at either 500, 600, 700 and 800 °C. A set of techniques (XRD, SEM-EDS, EBSD and GDOES) was used to characterize the surface microstructural and chemical changes. Nanoindentation was used to assess the induced changes in terms of mechanical properties. Two types of nitrided domains are revealed. Starting from the surface, a nitride bilayer composed of δ-TiN/ϵ-Ti2N with enhanced surface resistance is supported by an α-Ti(N) solid solution formed at depth. Hardness values peak at 12–14 GPa at the surface, which is almost twice as large as the bulk value (about 7 GPa). For the moderate temperatures used here, a deep (10–15 µm) and strong hardness (14 GPa) enhancement together with a smooth gradient can be achieved.
Microstructure and Friction Response of a Novel Eutectic Alloy Based on the Fe-C-Mn-B System
Authors: Tisov Oleksandr , Pashechko Mykhaylo , Yurchuk Alina , Chocyk Dariusz , Zubrzycki Jarosław , Prus Aleksandra , Wlazło-Ćwiklińska Magda
Published: December 2022

This paper focuses on the microstructure and tribological properties of novel hardfacing alloy based on Fe-C-Mn-B doped with Ni, Cr, and Si. The 4 mm-thick coating was deposited on the AISI 1045 carbon steel by the MIG-welding method using flux-cored wires in three passes. The transition zone thickness between the weld layers was ~80 μm, and the width of the substrate-coating interface was 5–10 μm. The following coating constituents were detected: coarser elongated M2B borides, finer particles of Cr7C3 carbides, and an Fe-based matrix consisting of ferrite and austenite. The nanohardness of the matrix was ~5–6 GPa, carbides ~16–19 GPa, and borides 22–23 GPa. A high cooling rate during coating fabrication leads to the formation of a fine mesh of M7C3 carbides; borides grow in the direction of heat removal, from the substrate to the friction surface, while in the transition zone, carbides become coarser. The dry sliding friction tests using a tribometer in PoD configuration were carried out at contact pressure 4, 7, 10, and 15 MPa against the AISI 1045 carbon steel (water-quenched and low-tempered, 50–52 HRC). The leading wear phenomenon at 4 and 7 MPa is fatigue, and at 10 and 15 MPa it is oxidation and delamination.
Microstructure Evaluation of the Potential of Additive Manufactured Dissimilar Titanium–Aluminum Alloys
Authors: Nagamatsu Hideaki , Abe Takeyuki , Sasahara Hiroyuki
Published: December 2022

Pure titanium (Ti) ERTi-2 was accumulated on an aluminum (Al) alloy ER5356 component via wire and arc additive manufacturing. The effect of processing parameters, mainly the input heat per unit length, on Ti/Al components was investigated. The microstructure of the Ti deposited layer and the Ti/Al reaction layer was analyzed using optical microscopy, scanning electron microscope, energy-dispersive spectroscopy, and an X-ray diffractometer. The fabrication of the surface layer equivalent to pure Ti as the used wire or Ti-Al alloy on the Al alloy components was achieved under low and high input heat conditions, respectively, although the Ti/Al components had low joinability and cracks at the reaction layer. Finally, the potential of additive-manufactured Ti/Al components with reference to our results and previous reports was discussed.
A Biomechanical Analysis of the Influence of the Morfology of the Bone Blocks Grafts on the Transfer of Tension or Load to the Soft Tissue by Means of the Finite Elements Method
Authors: Gil-Marques Blanca , Pallarés-Sabater Antonio , Brizuela-Velasco Aritza , Sánchez Lasheras Fernando , Lázaro-Calvo Pedro , Gómez-Adrián María Dolores , Larrazábal-Morón Carolina
Published: December 2022

Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations.
Assessment of a Bionic Broach Implanted with Nylon Fibers
Authors: Ni Jing , Zhang Haohan , Feng Kai , Zhao Huijun
Published: December 2022

The optimization of a broach surface is of great significance to improve the cutting performance of the tool. However, the traditional optimization method (surface texture, coating, etc.) destroys the stress distribution of the tool and reduces the service life of the tool. To avoid these problems, four kinds of flocking surfaces (FB1, FB2, FB3, and FB4), imitating the biological structure of Daphniphyllum calycinum Benth (DCB), were fabricated on the rake face of the broach by electrostatic flocking. The broaching experiment, wettability, and spreading experiment were then conducted. Moreover, the mathematical model of the friction coefficient of the bionic broach was built. The effect of broaches with different flocking surfaces on the broaching force, chip morphology, and surface quality of workpieces was studied. The results indicate that the flocked broaches (FB) with good lubricity and capacity of microchips removal (CMR) present a smaller cutting force (Fc) and positive pressure (Ft) compared to the unflocked broach (NB), and reduce the friction coefficient (COF). The chip curl was decreased, and the shear angle was increased by FB, which were attributed to the function of absorbing lubricant, storing, and sweeping microchips. Its vibration suppression effect enhanced the stability in the broaching process and improved the surface quality of the workpiece. More importantly, the FB2 with the most reasonable fluff area and spacing exhibited the best cutting performance. The experimental conclusions and methods of this paper can provide a new research idea for functional structure tools.
Microstructure and Mechanical Properties of MIG Welds between 6252 Armor Steel and Q550D HSLA Steel
Authors: Xu Xiangyu , Wang Gang , Zhang Runbo , Zhang Guangjun
Published: December 2022

The microstructure and mechanical properties of the welded joints of 6252 armor steel and Q550D high-strength low-alloy (HSLA) steel welded by MIG welding were studied. ER70S-G and ER140S-G were used as fillers to obtain welded joints with good formation and no faults. The joint microstructure (OM) analysis showed that a large Widmanstätten structure was observed at the fusion line on the Q550D side, and the apparent grain sizes changed on the 6252 side. Cylindrical ferrite growth along the bainite grain boundary was observed in the ER70S-G filler weld zone, while the ER140S-G filler weld zone was occupied by lower bainite structures. The XRD phase analysis showed that more Fe-Ni-Cr compounds and less ferrite were formed in the ER140S-G filler weld. The hardness test showed that the hardness of the HAZ on the 6252 side was significantly higher than that of the BM and the WZ, and the welded joint obtained by the ER140S-G filler had a higher hardness. The tensile strength test showed that WZ (>772 MPa) had a higher strength than Q550D BM, and the tensile fracture (SEM) was primarily a ductile fracture. The impact test results showed that the welded joint had better impact resistance at room temperature, but the impact absorption energy of the weld and the heat-affected zone was strongly affected by changes in temperature, and brittle fracture occurred easily at low temperatures.
The Mutual Incorporation of Mg2+ and CO32− into Hydroxyapatite: A DFT Study
Authors: Makshakova Olga N. , Gafurov Marat R. , Goldberg Margarita A.
Published: December 2022

Hydroxyapatite (HA) with a stoichiometry composition of Ca10(PO4)6(OH)2 is widely applied for various biomedical issues, first of all for bone defect substitution, as a catalyst, and as an adsorbent for soil and water purification. The incorporation of foreign ions changes the acid–base relation, microstructure, porosity, and other properties of the HA materials. Here, we report the results of calculations of the density functional theory and analyze the possibility of two foreign ions, CO32− and Mg2+, to be co-localized in the HA structure. The Na+ was taken into account for charge balance preservation. The analysis revealed the favorable incorporation of CO32− and Mg2+ as a complex when they interact with each other. The energy gain over the sole ion incorporation was pronounced when CO32− occupied the A position and Mg2+ was in the Ca(2) position and amounted to -0.31 eV. In the most energy-favorable complex, the distance between Mg2+ and the O atom of carbonate ion decreased compared to Mg…O distances to the surrounding phosphate or hydroxide ions, and amounted to 1.98 Å. The theoretical calculations agree well with the experimental data reported earlier. Understating the structure–properties relationship in HA materials varying in terms of composition, stoichiometry, and morphology paves the way to rational designs of efficient bio-based catalytic systems.
Effect of Modified Magnesium Oxide on the Properties of Magnesium Phosphate Cement under a Negative Temperature Environment
Authors: Luo Xuanzhang , Lai Zhenyu , Liu Zhi , Xiao Rui , Chen Jiawei , Lu Zhongyuan , Lv Shuzhen , Wang Jin
Published: December 2022

As a rapid repair material, magnesium phosphate cement (MPC) can be used under various environmental temperature conditions, but different temperatures significantly impact its strength and working performance. In this study, based on the surface modification of magnesium oxide, the working and mechanical properties of samples were investigated at an ambient temperature of −5 °C, and the hydration properties and microstructure of MPC were investigated using X-ray diffraction (XRD), thermogravimetric analysis (TG), mercury-in-pressure (MIP), and scanning electron microscopy (SEM). The results show that the modified magnesium oxide at a negative temperature prolongs the setting time of MPC from 10 min to more than 30 min, and fluidity can still be maintained or increased after half an hour. From 1 d to 28 d, the compressive strength growth rate of the reference group was 257.0% compared to 723.8% for the 10 wt% water-glass-modified MgO sample. K-struvite transformed from a blocky growth to a needle-like growth with the modified sample filling the pores and cracks inside the matrix. Compared with the unmodified sample, MPC’s porosity decreased from 9.62% to 9.23% for 10 wt% water-glass-modified MgO. Therefore, the surface modification of magnesium oxide not only prolonged the setting time but also further benefited mechanical performance, which provides the prerequisites for MPC construction in negative-temperature environments.
Effect of the Geometry of Thin-Walled Aluminium Alloy Elements on Their Deformations after Milling
Authors: Zawada-Michałowska Magdalena , Kuczmaszewski Józef , Pieśko Paweł
Published: December 2022

The aim of this paper is to analyse the effect of the selected geometric properties of thin-walled structures on post-machining deformations. In the study, EN AW-7075 T651 and EN AW-6082 T651 aluminium alloys were used to prepare specially designed thin-walled sample elements, i.e., elements with walls arranged in a semi-open and closed structure and with a dimension of 165 × 262 × 50.8 mm consisting of bottom and vertical stiffening walls and so-called ribs with a thickness of 1 mm. The measurements of the absolute deformations of the thin-walled bottom were performed with the use of a Vista coordinate-measuring machine by Zeiss with a PH10 head by Renishaw. Based on the obtained results, it was found that absolute deformation values were higher for walls arranged in a semi-open structure. It is related to a lower rigidity of the tested structure resulting from the lack of a stiffening wall, which is the so-called “rib”. Notwithstanding the geometry of the elements, greater absolute deformation values were recorded following conventional cutting methods. The use of high-speed cutting (HSC) provided positive outcomes in terms of minimising the deformation of thin-walled elements. Additionally, it was found that higher absolute deformations were obtained for EN AW-7075 T651 alloy.
Detection of Cobalamin and In Vitro Cell Imaging Based on Nitrogen-Doped Yellow Fluorescent Carbon Dots with Nano Architectonics
Authors: Yu Guang , Cheng Yujia , Duan Zhuohua
Published: December 2022

As novel fluorescent nanomaterials, carbon dots have attracted increasing research attention because of their simple synthesis, robust fluorescence, low toxicity, and easy functionalisation. Previous research was focused on preparing carbon dots from biomass and chemical materials; however, most of these carbon dots exhibited blue fluorescence. Moreover, the fluorescence quantum yield was generally low, significantly limiting their application in biological imaging. To broaden the application scope of carbon dots, this study prepared long-wavelength emitting nano-carbon dots that exhibited increased quantum yield. Novel N-doped yellow fluorescent nano-carbon dots (Y-CDs) were synthesised via a hydrothermal method using L-tartaric acid and urea as the precursors. The Y-CDs had a high quantum yield (15.9%) and demonstrated photostability at various pHs, temperatures, and ionic strengths. The Y-CDs could detect cobalamin effectively and selectively, showing a linear relationship between fluorescence intensity and cobalamin concentration. The related coefficient was 0.997, and the detection limit was 2.101 μmol/L. In addition, the Y-CDs were successfully used as an imaging probe for MDA-MB-231 cells. Therefore, the Y-CDs developed in this study can be used for cobalamin detection and cell imaging.
Pulse Burst Generation and Diffraction with Spatial Light Modulators for Dynamic Ultrafast Laser Materials Processing
Authors: Fang Zheng , Zhou Tong , Perrie Walter , Bilton Matthew , Schille Jörg , Löschner Udo , Edwardson Stuart , Dearden Geoff
Published: December 2022

A pulse burst optical system has been developed, able to alter an energetic, ultrafast 10 ps, 5 kHz output pulse train to 323 MHz intra-burst frequency at the fundamental 5 kHz repetition rate. An optical delay line consisting of a beam-splitting polariser cube, mirrors, and waveplates transforms a high-energy pulse into a pulse burst, circulating around the delay line. Interestingly, the reflected first pulse and subsequent pulses from the delay line have orthogonal linear polarisations. This fact allows independent modulation of these pulses using two-phase-only Spatial Light Modulators (SLM) when their directors are also aligned orthogonally. With hybrid Computer Generated Holograms (CGH) addressed to the SLMs, we demonstrate simultaneous multi-spot periodic surface micro-structuring on stainless steel with orthogonal linear polarisations and cylindrical vector (CV) beams with Radial and Azimuthal polarisations. Burst processing produces a major change in resulting surface texture due to plasma absorption on the nanosecond time scale; hence the ablation rates on stainless steel with pulse bursts are always lower than 5 kHz processing. By synchronising the scan motion and CGH application, we show simultaneous independent multi-beam real-time processing with pulse bursts having orthogonal linear polarisations. This novel technique extends the flexibility of parallel beam surface micro-structuring with adaptive optics.