bluuebunny/crossref_metadata_2025 huggingface dataset:
PIF and ReCiF: Efficient Interest-Packet Forwarding Mechanisms for Named-Data Wireless Mesh Networks
Authors: Matos Mascarenhas Dalbert , Monteiro Moraes Igor
Published: October 2018

In this paper, we propose three mechanisms to reduce the broadcast storm problem in wireless mesh networks based on the Named-Data Network (NDN) architecture. The goal of our mechanisms is to reduce the number of content requests forwarded by nodes and consequently, increase the network efficiency. The first proposed mechanism, called Probabilistic Interest Forwarding (PIF), randomly forwards content requests. The second mechanism, called Retransmission-Counter-based Forwarding (ReCIF), decides to forward content requests based on the number of retransmissions by adding a counter to the header of requests. The third mechanism, called ReCIF+PIF, combines the features of PIF and ReCIF to suppress content requests. We compare the performance of our mechanisms with both the NDN default forwarding mechanism and the Listen First Broadcast Later (LFBL) mechanism. Our proposals outperform the default NDN forwarding mechanism by up to 21% regarding the data delivery rate in dense networks and provide a 25% lower delivery delay than the default NDN. Our mechanisms accomplish this performance by only reducing the number of content requests forwarded by nodes. One of our mechanisms, PIF, outperforms LFBL regarding the data delivery rate and delivery delay by up to 263% and 55%, respectively, for high network contention levels.
Countering Superintelligence Misinformation
Authors: Baum Seth D.
Published: October 2018

Superintelligence is a potential type of future artificial intelligence (AI) that is significantly more intelligent than humans in all major respects. If built, superintelligence could be a transformative event, with potential consequences that are massively beneficial or catastrophic. Meanwhile, the prospect of superintelligence is the subject of major ongoing debate, which includes a significant amount of misinformation. Superintelligence misinformation is potentially dangerous, ultimately leading bad decisions by the would-be developers of superintelligence and those who influence them. This paper surveys strategies to counter superintelligence misinformation. Two types of strategies are examined: strategies to prevent the spread of superintelligence misinformation and strategies to correct it after it has spread. In general, misinformation can be difficult to correct, suggesting a high value of strategies to prevent it. This paper is the first extended study of superintelligence misinformation. It draws heavily on the study of misinformation in psychology, political science, and related fields, especially misinformation about global warming. The strategies proposed can be applied to lay public attention to superintelligence, AI education programs, and efforts to build expert consensus.
A Hybrid PAPR Reduction Method Based on SLM and Multi-Data Block PTS for FBMC/OQAM Systems
Authors: Wang Han
Published: October 2018

The filter bank multicarrier employing offset quadrature amplitude modulation (FBMC/OQAM) is a candidate transmission scheme for 5G wireless communication systems. However, it has a high peak-to-average power ratio (PAPR). Due to the nature of overlapped signal structure of FBMC/OQAM, conventional PAPR reduction schemes cannot work effectively. A hybrid PAPR reduction scheme based on selective mapping (SLM) and multi data block partial transmit sequence (M-PTS) methods is proposed for FBMC/OQAM signals in this paper. Different from the simple SLM-PTS method, the proposed hybrid algorithm takes into account the overlapping effect of multiple adjacent data blocks on its PTS process. From simulation results, it can be obtained that the proposed method can offer a significant PAPR reduction performance improvement compared with the SLM, PTS and SLM-PTS methods. The proposed method can effectively reduce the PAPR in FBMC/OQAM systems.
Design of Molecular Water Oxidation Catalysts Stabilized by Ultrathin Inorganic Overlayers—Is Active Site Protection Necessary?
Authors: Sévery Laurent , Siol Sebastian , Tilley S. David
Published: October 2018

Anchored molecular catalysts provide a good step towards bridging the gap between homogeneous and heterogeneous catalysis. However, applications in an aqueous environment pose a serious challenge to anchoring groups in terms of stability. Ultrathin overlayers embedding these catalysts on the surface using atomic layer deposition (ALD) are an elegant solution to tackle the anchoring group instability. The propensity of ALD precursors to react with water leads to the question whether molecules containing aqua ligands, such as most water oxidation complexes, can be protected without side reactions and deactivation during the deposition process. We synthesized two iridium and two ruthenium-based water oxidation catalysts, which contained an aqua ligand (Ir–OH2 and Ru–OH2) or a chloride (Ir–Cl and Ru–Cl) that served as a protecting group for the former. Using a ligand exchange reaction on the anchored and partially embedded Ru–Cl, the optimal overlayer thickness was determined to be 1.6 nm. An electrochemical test of the protected catalysts on meso-ITO showed different behaviors for the Ru and the Ir catalysts. The former showed no onset difference between protected and non-protected versions, but limited stability. Ir–Cl displayed excellent stability, whilst the unprotected catalyst Ir–OH2 showed a later initial onset. Self-regeneration of the catalytic activity of Ir–OH2 under operating conditions was observed. We propose chloride ligands as generally applicable protecting groups for catalysts that are to be stabilized on surfaces using ALD.
The Effect of Neonicotinoid Insecticide and Fungicide on Sugar Responsiveness and Orientation Behavior of Honey Bee (Apis mellifera) in Semi-Field Conditions
Authors: Jiang Xingchuan , Wang Zhengwei , He Qibao , Liu Qiongqiong , Li Xinyang , Yu Linsheng , Cao Haiqun
Published: October 2018

Neonicotinoid insecticides are in widespread use around the world, cause pollinator decline. We used semi-field conditions to determine the effect of sublethal insecticide, thiamethoxam, exposure on orientation behavior and sugar responsiveness. Bees could not reject the non-treated flower or the insecticide or insecticide/fungicide treated flower. After bees consumed the insecticide or insecticide/fungicide treated nectar, they could not discriminate between a flower odor or blank control in a Y-maze when making a first choice. We also found that treated bees wander back and forth in both arms to make a final decision about food location, and used longer duration in the Y maze than the control group. Sugar responsiveness was also reduced after bees were fed with insecticide or insecticide/fungicide treated food, one week was needed for them to display the same level of responsiveness as the control group. The thiamethoxam or thiamethoxam/carbendazol treated crop field does not act as an olfactory repellent to the bee, but it does affect its post-consumption behavior.
An Alternative Perspective for the Theory of Biological Control
Authors: Mills Nicholas J.
Published: October 2018

Importation biological control represents the planned introduction of a specialist natural enemy from the region of origin of an invasive pest or weed. For this study, the author considered why attempts to develop a predictive theory for biological control have been misguided and what future directions might be more promising and effective. Despite considerable interest in the theory of consumer–resource population dynamics, such theory has contributed little to improvements in the success of biological control due to a focus on persistence and equilibrium dynamics rather than establishment and impact. A broader consideration of invasion biology in addition to population ecology offers new opportunities for a more inclusive theory of biological control that incorporates the demographic and genetic processes that more specifically address the establishment and impact of introduced natural enemies. The importance of propagule size and genetic variance for successful establishment, and of contributions to host population growth, relative population growth rates, interaction strength, and coevolution for suppression of host abundance are discussed as promising future directions for a theory of biological control.
Effects of Jaw Periosteal Cells on Dendritic Cell Maturation
Authors: Dai Jingtao , Rottau Daniela , Kohler Franziska , Reinert Siegmar , Alexander Dorothea
Published: October 2018

Clinical application of tissue engineering products requires the exclusion of immune responses after implantation. We used jaw periosteal cells (JPCs) as a suitable stem cell source and analyzed herein the effects of JPCs on dendritic cell maturation after co-culturing of both cell types. Peripheral blood mononuclear cells (PBMCs) were differentiated to dendritic cells (DCs) by the addition of differentiation cocktails for 7 days in co-culture with undifferentiated and osteogenically induced JPCs. The effects of JPCs on DC maturation were analyzed at the beginning (day 7), in the middle (day 14), and at the end (day 21) of the osteogenesis process. We detected significantly lower DC numbers after co-culturing with JPCs that have previously been left untreated or osteogenically differentiated for 7, 14, and 21 days. Using gene expression analyses, significantly lower IL-12p35 and -p40 and pro-inflammatory cytokine (IFN-γ and TNF-α) levels were detected, whereas IL-8 mRNA levels were significantly higher in DCs. Furthermore, osteogenic media conditions enhanced significantly IL-10 gene expression. We concluded that undifferentiated and osteogenically differentiated JPCs had an overall inhibiting influence on dendritic cell maturation. Further studies should clarify the underlaying mechanism in depth.
Association of Renal Function and Direct-Acting Antiviral Agents for HCV: A Network Meta-Analysis
Authors: Kao Chih-Chin , Lin Yu-Shiuan , Chu Heng-Cheng , Fang Te-Chao , Wu Mai-Szu , Kang Yi-No
Published: October 2018

The effectiveness and safety of direct-acting antiviral agents (DAAs) in hepatitis C virus (HCV) patients with renal insufficiency remain controversial. Therefore, this network meta-analysis aims to assess effectiveness and safety of DAAs in populations with different renal function. The pooled data were obtained from Cochrane Library, EMBASE, PubMed, and Web of Science. Thirteen studies recruited 6884 patients with hepatitis C infection and reported their outcomes in relation to different levels of renal function after treatment with DAAs. The results showed no difference in the virologic responses among patients with different renal function. Regarding safety, whereas in patients without chronic kidney disease (CKD) or with early CKD DAAs were associated with a risk ratio (RR) of 0.14 (95% confidence interval (CI), 0.04 to 0.43) for renal disorder, increased risk of renal function deterioration was found in advanced-CKD patients, though this effect may be related to the natural course of advanced CKD. Similarly, patients without CKD or with early CKD showed a lower risk of anemia (RR, 0.34; 95% CI, 0.20 to 0.57) and discontinuation (RR, 0.41; 95% CI, 0.39 to 0.56) than patients with advanced CKD. The efficacy of DAAs for HCV treatment was comparable in patients with advanced CKD and in those with early CKD or without CKD. However, the safety of DAAs should be verified in future studies.
Can Photoplethysmography Replace Arterial Blood Pressure in the Assessment of Blood Pressure?
Authors: Martínez Gloria , Howard Newton , Abbott Derek , Lim Kenneth , Ward Rabab , Elgendi Mohamed
Published: October 2018

Arterial Blood Pressure (ABP) and photoplethysmography (PPG) are both useful techniques to monitor cardiovascular status. Though ABP monitoring is more widely employed, this procedure of signal acquisition whether done invasively or non-invasively may cause inconvenience and discomfort to the patients. PPG, however, is simple, noninvasive, and can be used for continuous measurement. This paper focuses on analyzing the similarities in time and frequency domains between ABP and PPG signals for normotensive, prehypertensive and hypertensive subjects and the feasibility of the classification of subjects considering the results of the analysis performed. From a database with 120 records of ABP and PPG, each 120 s in length, the records where separated into epochs taking into account 10 heartbeats, and the following statistical measures were performed: Correlation (r), Coherence (COH), Partial Coherence (pCOH), Partial Directed Coherence (PDC), Directed Transfer Function (DTF), Full Frequency Directed Transfer Function (ffDTF) and Direct Directed Transfer Function (dDTF). The correlation coefficient was r > 0.9 on average for all groups, indicating a strong morphology similarity. For COH and pCOH, coherence (linear correlation in frequency domain) was found with significance (p < 0.01) in differentiating between normotensive and hypertensive subjects using PPG signals. For the dataset at hand, only two synchrony measures are able to convincingly distinguish hypertensive subjects from normotensive control subjects, i.e., ffDTF and dDTF. From PDC, DTF, ffDTF, and dDTF, a consistent, a strong significant causality from ABP→PPG was found. When all synchrony measures were combined, an 87.5 % accuracy was achieved to detect hypertension using a Neural Network classifier, suggesting that PPG holds most informative features that exist in ABP.
Acute Kidney Injury in Pregnancy: The Need for Higher Awareness. A Pragmatic Review Focused on What Could Be Improved in the Prevention and Care of Pregnancy-Related AKI, in the Year Dedicated to Women and Kidney Diseases
Authors: Piccoli Giorgina Barbara , Zakharova Elena , Attini Rossella , Ibarra Hernandez Margarita , Covella Bianca , Alrukhaimi Mona , Liu Zhi-Hong , Ashuntantang Gloria , Orozco Guillen Alejandra , Cabiddu Gianfranca , Li Philip Kam Tao , Garcia-Garcia Gulliermo , Levin Adeera
Published: October 2018

Pregnancy-related acute kidney injury (pAKI), preeclampsia (PE), and the hypertensive disorders of pregnancy are closely related conditions, which are, in turn, frequently linked to pre-existing and often non-diagnosed chronic kidney disease (CKD). The current literature and research mainly underline the effects of pregnancy complications on the offspring; this review strongly emphasizes the maternal health as well. These conditions not only negatively affect pregnancy outcomes, but have a relevant effect on the future health of affected mothers and their children. Therefore, dedicated diagnostic and follow-up programs are needed, for optimizing materno-foetal health and reducing the impact of pregnancy-related problems in the mothers and in the new generations. This narrative review, performed on the occasion of the 2018 World Kidney Day dedicated to women’s health, focuses on three aspects of the problem. Firstly, the risk of AKI in the hypertensive disorders of pregnancy (the risk is the highest in developing countries; however PE is the main cause of pregnancy related AKI worldwide). Secondly, the effect of AKI and the hypertensive disorders of pregnancy on the development of CKD in the mother and offspring: long-term risks are increased; the entity and the trajectories are still unknown. Thirdly, the role of CKD in the pathogenesis of AKI and the hypertensive disorders of pregnancy: CKD is a major risk factor and the most important element in the differential diagnosis; pregnancy is a precious occasion for early diagnosis of CKD. Higher awareness on the importance of AKI in pregnancy is needed to improve short and long term outcomes in mothers and children.
Hand Laser Perfusion Imaging to Assess Radial Artery Patency: A Pilot Study
Authors: Indolfi Ciro , Passafaro Francesco , Sorrentino Sabato , Spaccarotella Carmen , Mongiardo Annalisa , Torella Daniele , Polimeni Alberto , Sabatino Jolanda , Curcio Antonio , De Rosa Salvatore
Published: October 2018

Objectives: To test a novel diagnostic technique to assess radial artery perfusion after transradial catheterization. Background: Despite being mostly asymptomatic, radial artery occlusion (RAO) is not a benign complication, and its diagnosis is frequently missed because it requires time-consuming diagnostic testing. We developed a novel operator-independent diagnostic test to assess RAO after coronary procedures through a transradial access (TRA) by means of hand Laser Perfusion Imaging (LPI). Methods: One hundred patients were evaluated before and after TRA by means of the LPI. A radial perfusion index (RPI) was calculated as the ratio between the total perfusion measured during ulnar occlusion and total basal perfusion. Vascular Duplex scan (VDS) was used as the standard of reference to assess the artery patency. Results: LPI correctly identified RAO in 100% of cases. Post-procedural RPI was 0.89 ± 0.13 in patients with radial patency vs. 0.15 ± 0.04 in patients with RAO (p < 0.001). In line with these results, ROC analysis showed an excellent diagnostic performance of the LPI, that correctly identified all RAO cases (Area Under the Curve, AUC = 1.0; p < 0.001), with an optimal diagnostic cutoff at 0.2 RPI. Conclusions: LPI is a reliable diagnostic technique for RAO, offering the advantages of being quick and simple to perform.
Path Planning for Highly Automated Driving on Embedded GPUs
Authors: Fickenscher Jörg , Schmidt Sandra , Hannig Frank , Bouzouraa Mohamed Essayed , Teich Jürgen
Published: October 2018

The sector of autonomous driving gains more and more importance for the car makers. A key enabler of such systems is the planning of the path the vehicle should take, but it can be very computationally burdensome finding a good one. Here, new architectures in Electronic Control Units (ECUs) are required, such as Graphics Processing Units (GPUs), because standard processors struggle to provide enough computing power. In this work, we present a novel parallelization of a path planning algorithm. We show how many paths can be reasonably planned under real-time requirements and how they can be rated. As an evaluation platform, an Nvidia Jetson board equipped with a Tegra K1 System-on-Chip (SoC) was used, whose GPU is also employed in the zFAS ECU of the AUDI AG.
The Implementation Process for Pharmacogenomic Testing for Cancer-Targeted Therapies
Authors: Wu Ann Chen , Mazor Kathleen M. , Ceccarelli Rachel , Loomer Stephanie , Lu Christine Y.
Published: October 2018

Recent advances in genomic medicine have led to the availability of genomic tests that have the potential to improve population health, yet the process for obtaining these tests and getting them reimbursed by insurers has not been described. The objective of this study was to describe the process of ordering pharmacogenomic tests by interviewing providers, patients, and laboratories about cancer-related pharmacogenomic tests. We interviewed patients who were prescribed, providers who prescribed medications that should be guided by pharmacogenomic testing, and individuals from diagnostic laboratories. A total of 10 providers, 16 patients, and eight diagnostic laboratories described logistical and insurance issues relating to ordering and receiving pharmacogenomic tests and medications. We found that the process of ordering pharmacogenomic tests is time-consuming, expensive, and complex. Ordering pharmacogenomic tests is quite different across institutions. Even in the same institution, multiple providers can order the test. Once the provider places the order for the pharmacogenomic test, the laboratory receives the request and usually begins testing without knowing how the test will be paid for. Next, the laboratory completes the pharmacogenomic testing and the results of the tests are reported to providers, patients, or placed directly in the medical record. In conclusion, processes related to ordering and obtaining insurance coverage for pharmacogenomic tests varies greatly across institutions and is time-consuming.
A Test of Market Efficiency When Short Selling Is Prohibited: A Case of the Dhaka Stock Exchange
Authors: Sochi Maria , Swidler Steve
Published: October 2018

A ban on short selling exists on several exchanges, especially in emerging markets. In most cases, short selling has always been prohibited, thus making it difficult to examine the ban’s effect on price discovery. In this paper, we consider data from the Dhaka Stock Exchange (DSE) to test for a short selling ban on market efficiency. The analysis examines runs in daily stock returns and then forms a distribution of return clusters according to their duration. Using Monte Carlo simulation, we find that runs of longer duration appear more frequently in the DSE data than we would expect in efficient markets. We compare these results to stocks in the Dow Jones Industrial Average (DJIA). We find that the same runs tests accord with market efficiency for liquid and easily shorted DJIA stocks.
The Effect of the Gully Land Consolidation Project on Soil Erosion and Crop Production on a Typical Watershed in the Loess Plateau
Authors: Han Xiaoliang , Lv Peiyi , Zhao Sen , Sun Yan , Yan Shiyu , Wang Minghao , Han Xiaona , Wang Xiuru
Published: October 2018

The Gully Land Consolidation Project (GLCP) was launched to create more arable land by excavating soil from the slopes on both sides of gullies, combined with simultaneous comprehensive gully prevention and control measures. The purpose of the GLCP is to increase crop production and reduce soil erosion to achieve ecological and agricultural sustainability. In this study, we assess the effects of the GLCP on soil erosion and crop production by studying the BaoChengGou Watershed in the Loess Plateau, primarily by means of high spatial-resolution satellite images (taken by the GF-1 and ZY-3 satellites) combined with the InVEST model and field investigations. Sloping cropland, sparse forestland, and natural grassland are the main land use types in the study area. After implementing the GLCP, consolidated land in the cropland increased by 7.35%, an increase that has come largely at the expense of grassland and forestland. The GLCP has markedly reduced soil erosion in the BaoChengGou Watershed, especially in the sense that soil erosion intensity was also reduced significantly in the project region on the whole, despite intensifying in certain places, such as excavated slopes; furthermore, it has improved crop yields in the study area by 10.9%. Comprehensive measurement shows the GLCP to be scientific, reasonable, and clearly efficacious. This study presents findings regarding the positive significance of the GLCP in promoting ecological and agricultural sustainability in the Loess Plateau.
Possible Emergence of Sequence Specific RNA Aminoacylation via Peptide Intermediary to Initiate Darwinian Evolution and Code through Origin of Life
Authors: Kunnev Dimiter , Gospodinov Anastas
Published: October 2018

One of the most intriguing questions in biological science is how life originated on Earth. A large number of hypotheses have been proposed to explain it, each putting an emphasis on different events leading to functional translation and self-sustained system. Here, we propose a set of interactions that could have taken place in the prebiotic environment. According to our hypothesis, hybridization-induced proximity of short aminoacylated RNAs led to the synthesis of peptides of random sequence. We postulate that among these emerged a type of peptide(s) capable of stimulating the interaction between specific RNAs and specific amino acids, which we call “bridge peptide” (BP). We conclude that translation should have emerged at the same time when the standard genetic code begun to evolve due to the stabilizing effect on RNA-peptide complexes with the help of BPs. Ribosomes, ribozymes, and the enzyme-directed RNA replication could co-evolve within the same period, as logical outcome of RNA-peptide world without the need of RNA only self-sustained step.
Combined Analytical and Experimental Evaluation of Frictional Performance of Lubricated Untextured and Partially Textured Sliders
Authors: Teo Wei J. , Dolatabadi Nader , Rahmani Ramin , Morris Nick , Rahnejat Homer
Published: October 2018

The study of textured surface performance is one of the highly researched topics in recent times. This is mainly due to the advantages that such surfaces can potentially provide in practice, in mitigating adverse tribological conditions, such as friction and wear. However, considering the complexities found in practice, a methodological analysis and evaluation procedure is essential in order to gain an understanding of the benefits from utilising such features in a given contact. The current study provides a combined analytical and experimental approach towards an enhanced understanding of the behaviour of textured surfaces relative to their untextured counterparts. The developed analytical models are invaluable in providing an insight into the relationship between the many parameters involved in defining even simple surface texture feature geometry and the expected outcomes in practice, when corroborated with experimental results. The current study reports on such an endeavour. With the studied texture configuration, the results have shown the possibility of reducing friction by as much as 25%.
Synthesis of 4-(2H-[1,2,4]-Triazol-5-ylsulfanyl)-1,2-dihydropyrazol-3-one via Ring-Switching Hydrazinolysis of 5-Ethoxymethylidenethiazolo [3,2-b][1,2,4]triazol-6-one
Authors: Holota Serhii , Shylych Yaroslav , Derkach Halyna , Karpenko Olexandr , Gzella Andrzej , Lesyk Roman
Published: October 2018

4-(1H-[1,2,4]-Triazol-5-ylsulfanyl)-1,2-dihydropyrazol-3-one (4) was synthesized with a yield of 55% via ring-switching hydrazinolysis of 5-ethoxymethylidenethiazolo[3,2-b][1,2,4] triazol-6-one (3) in ethanol medium. The initial 1H-[1,2,4]-triazole-3-thiol (1) was modified via a two-step reaction: S-alkylation with chloroacetic acid under Williamson reaction conditions, and further one-pot cyclization–condensation with triethylorthoformate in the acetic anhydride medium, yielding compound 3. The structures of compounds 3 and 4 were confirmed by LC-MS, NMR spectra and a single X-ray diffraction analysis (for compound 4).
Sintering Behavior and Mechanical Properties of Mullite Fibers/Hydroxyapatite Ceramic
Authors: Zhao Xueni , Liu Qingyao , Yang Jianjun , Zhang Weigang , Wang Yao
Published: October 2018

The effect of fiber content and sintering temperature on sintering behavior and mechanical properties of mullite fibers/hydroxyapatite composites was studied. The composites were fabricated by hydrothermal synthesis and pressureless sintering. The amount of fibers was varied from 5 wt % to 15 wt % through hydrothermal synthesis, mullite fibers and hydroxyapatite composite powders were subsequently sintered at temperatures of 1150, 1250, and 1350 °C. The composites presented a more perturbed structure by increasing fiber content. Moreover, the composites experienced pore coalescence and exhibited a dense microstructure at elevated temperature. X-ray diffraction indicated that the composites underwent various chemical reactions and generated silicate glasses. The generation of silicate glasses increased the driving force of particle rearrangement and decreased the number of pores, which promoted densification of the composites. Densification typically leads to increased hardness and bending strength. The study proposes a densification mechanism and opens new insights into the sintering properties of these materials.
In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process
Authors: Chen Rongchuang , Zheng Zhizhen , Li Jianjun , Li Ning , Feng Fei
Published: October 2018

The relationships between initial microstructures, process parameters, and grain evolutions in isothermal holdings have drawn wide attention in recent years, but the grain growth behaviors of 300M steel were not well understood, resulting in a failure in precise microstructure controlling in heat treatment. In this work, in situ observations were carried out to characterize the grain evolutions of 300M steel with varying holding time, holding temperatures, and initial microstructures. The intriguing finding was that the grain refinement by austenization of 300M steel was followed by a dramatic grain growth in the initial stage of holding (≤~600 s), and with increasing time (~600–7200 s), the average grain size appeared to have a limit value at specific temperatures. The austenization process accelerated the grain growth by generating large quantity of grain boundaries at the initial stage of holdings, and the growth rate gradually slowed down after holding for ~600 s because the driven force was weakened due to the reduction of grain boundary energy. The initial structure and the initial grain size of 300M steel had no obvious influences on the grain size evolutions. The mechanisms of grain growth were analyzed based on in situ observations and transmission electron microscope (TEM) characterizations. A grain evolution model considering the grain boundary migration of 300M steel was established for the isothermal holding process. Good agreement was obtained between the in situ observation results and the model calculation results. This investigation aimed to understand fundamentally the grain evolutions of 300M steel in the isothermal holding process.
Fabrication of Micro-Parts with High-Aspect Ratio Micro-Hole Array by Micro-Powder Injection Molding
Authors: Wang Changrui , Lu Zhen , Zhang Kaifeng
Published: October 2018

The present study investigated high-aspect ratio micro-hole array parts which were made by ZrO2 micro-powder with different particle sizes and micro-powder injection molding technology. It analysed the influence of particle sizes on feedstock, debinding and sintering of ceramic nozzles with multi-micro-holes. The forming quality of ceramic nozzles with multi-micro-holes was discussed in this paper. The results show that the two mixed ZrO2 feedstocks have fine uniformity. The average deviation of the feedstock made with 200 nm powder was −2%, and the average deviation of the feedstock made with 100 nm powder was −7.1%. The sample showed certain sintering characteristics which provided better strength (11.10 MPa) to parts after debinding. The linear shrinkage and the density of the two powder samples at different sintering temperatures increased as the sintering temperature increased. If the temperature continued to increase, the linear shrinkage and the density decreased. The highest hardness and flexural strength values of the ZrO2 sample with 200 nm powder used were: 1265.5 HV and 453.4 MPa, and the crystalline particle size was 0.36 μm. The highest hardness and flexural strength values of the ZrO2 sample with 100 nm powder used were: 1425.8 HV and 503.6 MPa, and the crystalline particle size was 0.18 μm. The ceramic nozzles with multi-micro holes shrunk to nearly the same axial, radial and circumferential directions during sintering. After sintering, the roundness of ceramic micro-hole met the user requirements, and the circular hole had a high parallelism in the axial direction. The micropore diameter was 450 ± 5 μm, and it was possible to control the dimensional accuracy within 1.5% after sintering. The study presented a superior application prospect for high-aspect ratio micro hole array parts in aerospace, electronics and biomedicine.
Metal–Organic Framework Thin Film-Based Dye Sensitized Solar Cells with Enhanced Photocurrent
Authors: Ahmad Shargeel , Liu Jinxuan , Ji Wei , Sun Licheng
Published: October 2018

Metal–organic framework thin film-based dye sensitized solar cell is fabricated with highly oriented, crystalline, and porous Zn-perylene metal-organic framework (MOF) thin film (SURMOF) which is integrated with Bodipy embedded in poly(methyl methacrylate). It has been demonstrated that the photocurrent can be enhanced by a factor of 5 relative to Zn-perylene MOF thin film due to triplet–triplet annihilation up-conversion between the Bodipy/PMMA sensitizer and the Zn-perylene MOF thin film acceptor using Co(bpy)32+/3+ as redox mediator.
Mechanical Metamaterials Foams with Tunable Negative Poisson’s Ratio for Enhanced Energy Absorption and Damage Resistance
Authors: Cui Shaohua , Gong Baoming , Ding Qian , Sun Yongtao , Ren Fuguang , Liu Xiuguo , Yan Qun , Yang Hai , Wang Xin , Song Bowen
Published: October 2018

Systematic and deep understanding of mechanical properties of the negative Poisson’s ratio convex-concave foams plays a very important role for their practical engineering applications. However, in the open literature, only a negative Poisson’s ratio effect of the metamaterials convex-concave foams is simply mentioned. In this paper, through the experimental and finite element methods, effects of geometrical morphology on elastic moduli, energy absorption, and damage properties of the convex-concave foams are systematically studied. Results show that negative Poisson’s ratio, energy absorption, and damage properties of the convex-concave foams could be tuned simultaneously through adjusting the chord height to span ratio of the sine-shaped cell edges. By the rational design of the negative Poisson’s ratio, when compared to the conventional open-cell foams of equal mass, convex-concave foams could have the combined advantages of relative high stiffness and strength, enhanced energy absorption and damage resistance. The research of this paper provides theoretical foundations for optimization design of the mechanical properties of the convex-concave foams and thus could facilitate their practical applications in the engineering fields.
A Study on the Effect of Ultrasonic Treatment on the Microstructure of Sn-30 wt.% Bi Alloy
Authors: Wang Shuo , Kang Jinwu , Zhang Xiaopeng , Guo Zhipeng
Published: October 2018

The effect of ultrasonic treatment on the microstructure of Sn-30 wt.% Bi alloy was studied at different temperatures. Results showed that the ultrasonic treatment could effectively refine the microstructure of Sn-30 wt.% Bi alloy at a temperature range between the liquidus and solidus. Application of the ultrasound could fragment the primary Sn dendrites during solidification due to a mixed effect of ultrasonic cavitation and acoustic streaming. The divorced eutectic formed when the ultrasonic treatment was applied for the whole duration of the solidification. The eutectic phase grew and surrounded the primary Sn dendrite, and pure Bi phase grew in between the Sn dendritic fragments. The mechanism of the fragmentation of dendrites and the divorced eutectic structure by ultrasonic treatment was discussed.
High-Performance Thin Film Transistor with an Neodymium-Doped Indium Zinc Oxide/Al2O3 Nanolaminate Structure Processed at Room Temperature
Authors: Yao Rihui , Li Xiaoqing , Zheng Zeke , Zhang Xiaochen , Xiong Mei , Xiao Song , Ning Honglong , Wang Xiaofeng , Wu Yuxiang , Peng Junbiao
Published: October 2018

In this work, a high-performance thin film transistor with an neodymium-doped indium zinc oxide (Nd:IZO) semiconductor via a room temperature approach and adopting the Nd:IZO/Al2O3 nanolaminate structure was investigated. The effects of the ultrathin Al2O3 layer and the thickness of Nd:IZO layer in the nanolaminate structure on the improvement of electrical performance and stability of thin film transistors (TFTs) were systematically studied. Besides the carrier movement confined along the near-channel region, driven by the Al2O3 layer under an electrical field, the high performance of the TFT is also attributed to the high quality of the 8-nm-thick Nd:IZO layer and the corresponding optimal Nd:IZO/Al2O3 interface, which reduce the scattering effect and charge trapping with strong M–O bonds in bulk and the back-channel surface of Nd:IZO, according to the X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and micro-wave photo conductivity decay (μ-PCD) results. As a result, the Nd:IZO/Al2O3 TFT exhibits an outstanding performance, with a high μsat of 32.7 cm2·V−1·s−1, an Ion/Ioff of 1.9 × 108, and a low subthreshold swing (SS) value of 0.33 V·dec−1, which shows great potential for the room temperature fabrication of TFTs in high-resolution or high-frame-rate displays by a scalable, simple, and feasible approach.
Influence of Dielectric Barrier Discharge Treatment on Surface Structure of Polyoxymethylene Fiber and Interfacial Interaction with Cement
Authors: Zhang Wei , Xu Xiao , Wei Fayun , Zou Xueshu , Zhang Yu
Published: October 2018

Polyoxymethylene (POM) fiber was treated with atmospheric dielectric barrier discharge (DBD) plasma to enhance the surface activity of the fiber and interfacial interaction with cement. The physical and chemical properties of samples with different DBD plasma treatment durations were tested and analyzed. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the surface roughness of the sample increased significantly as a result of the DBD plasma treatment. Fourier transform infrared spectrophotometer (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that a large number of –COH and –COOH groups were formed on the surface of the sample after DBD plasma treatment. The hydrophilicity of the POM fiber was greatly improved with the increase in the treatment duration. When the treatment duration was longer than 120 s, the fiber surface contact angle decreased from 90° to 43°. The DBD plasma treatment resulted in a decrease in the tensile strength of the POM fiber, but the increase in the amount of –COH and –COOH on the surface of the POM fiber and the increase in the roughness resulted in an increase in the fiber pull-out bonding strength in cement from 2.15 N to 4.68 N.
Effects of Inoculation on the Pearlitic Gray Cast Iron with High Thermal Conductivity and Tensile Strength
Authors: Wang Guiquan , Chen Xiang , Li Yanxiang , Liu Zhongli
Published: October 2018

With the aim of improving the thermal conductivity and tensile strength of pearlitic gray cast iron, the influence of inoculation on structure and properties was experimentally investigated. Three group of irons with similar compositions were inoculated by Zr-FeSi, Sr-FeSi, and SiC inoculants, respectively. The metallographic analysis was used to measure the maximum graphite length, primary dendrites amount and eutectic colonies counts. For a certain carbon equivalent, it was confirmed that the thermal conductivity of pearlitic gray cast iron has a direct correlation with the maximum graphite length while the tensile strength was influenced mainly by the primary dendrites amount. The optimal structure and highest thermal conductivity and tensile strength were obtained by Sr-FeSi inoculant. MnS particles act a pivotal part in modifying the structure of gray cast iron. It was found that providing nucleation sites both for graphite and primary austenite is important to promote the thermal conductivity and strength. However, excessive nuclei (MnS particles) results in shorter graphite flakes and thus the depressive growth of primary dendrites.
Developing Lignosulfonate-Based Activated Carbon Fibers
Authors: Chang Feng-Cheng , Yen Shih-Hsuan , Wang Szu-Han
Published: October 2018

In this study, electrospinning technology, physical activation, and carbonization processing were applied to produce lignosulfonate-based activated carbon fibers. The porous structure of the produced lignosulfonate-based activated carbon fibers primarily contained mesopores and a relatively small amount of micropores. Moreover, insufficient carbonization caused fiber damage during CO2 activation. The weight loss rate and specific surface area increased with increase in carbonization time, and products with carbonization temperatures of 700 °C were of higher quality than those with other temperatures. Moreover, the two-step carbonization process provided fibers with improved quality because of a low weight loss rate, improved processing, and high surface area. Lignosulfonate-based activated carbon fibers can be used as a highly efficient adsorption and filtration material, and further development of its applications would be valuable.
Fabricating a Novel Intragranular Microstructure for Al2O3/GdAlO3 Ceramic Composites
Authors: Sun Shuai , Xu Qiang
Published: October 2018

In order to make the embryonic form of intragranular structure, the Al2O3/GdAlO3 system was selected due to its excellent mechanical properties. Gd2O3 and Al(NO3)3·9H2O were used as the starting materials. A co-precipitation method was used for the preparation of fine ceramics and applied to synthesize the nano-powder of GdAlO3 firstly. Then, the nano-powder of GdAlO3 was mixed with the precipitates by the second co-precipitation method. After drying and calcination, the compound powder with eutectic composition (77 mol % Al3+—23 mol % Gd3+) was fast sintered by using the spark plasma sintering technique. The results revealed that the phases of the sintered samples were Al2O3 and GdAlO3. The phases showed a homogeneous and interlaced distribution. All the matrix grains were submicron. The sizes of the intragranular structures were between 50 nm and 150 nm. Therefore, the intragranular structure displayed a novel mixture of nanometer–submicron and submicron–submicron types. The different intragranular structures all changed the fracture modes of Al2O3 grains from intergranular fracture to transgranular fracture.
Encapsulation of Rat Bone Marrow Derived Mesenchymal Stem Cells in Alginate Dialdehyde/Gelatin Microbeads with and without Nanoscaled Bioactive Glass for In Vivo Bone Tissue Engineering
Authors: Rottensteiner-Brandl Ulrike , Detsch Rainer , Sarker Bapi , Lingens Lara , Köhn Katrin , Kneser Ulrich , Bosserhoff Anja , Horch Raymund , Boccaccini Aldo , Arkudas Andreas
Published: October 2018

Alginate dialdehyde (ADA), gelatin, and nano-scaled bioactive glass (nBG) particles are being currently investigated for their potential use as three-dimensional scaffolding materials for bone tissue engineering. ADA and gelatin provide a three-dimensional scaffold with properties supporting cell adhesion and proliferation. Combined with nanocristalline BG, this composition closely mimics the mineral phase of bone. In the present study, rat bone marrow derived mesenchymal stem cells (MSCs), commonly used as an osteogenic cell source, were evaluated after encapsulation into ADA-gelatin hydrogel with and without nBG. High cell survival was found in vitro for up to 28 days with or without addition of nBG assessed by calcein staining, proving the cell-friendly encapsulation process. After subcutaneous implantation into rats, survival was assessed by DAPI/TUNEL fluorescence staining. Hematoxylin-eosin staining and immunohistochemical staining for the macrophage marker ED1 (CD68) and the endothelial cell marker lectin were used to evaluate immune reaction and vascularization. After in vivo implantation, high cell survival was found after 1 week, with a notable decrease after 4 weeks. Immune reaction was very mild, proving the biocompatibility of the material. Angiogenesis in implanted constructs was significantly improved by cell encapsulation, compared to cell-free beads, as the implanted MSCs were able to attract endothelial cells. Constructs with nBG showed higher numbers of vital MSCs and lectin positive endothelial cells, thus showing a higher degree of angiogenesis, although this difference was not significant. These results support the use of ADA/gelatin/nBG as a scaffold and of MSCs as a source of osteogenic cells for bone tissue engineering. Future studies should however improve long term cell survival and focus on differentiation potential of encapsulated cells in vivo.
Interference of Biodegradable Plastics in the Polypropylene Recycling Process
Authors: Samper María Dolores , Bertomeu David , Arrieta Marina Patricia , Ferri José Miguel , López-Martínez Juan
Published: October 2018

Recycling polymers is common due to the need to reduce the environmental impact of these materials. Polypropylene (PP) is one of the polymers called ‘commodities polymers’ and it is commonly used in a wide variety of short-term applications such as food packaging and agricultural products. That is why a large amount of PP residues that can be recycled are generated every year. However, the current increasing introduction of biodegradable polymers in the food packaging industry can negatively affect the properties of recycled PP if those kinds of plastics are disposed with traditional plastics. For this reason, the influence that generates small amounts of biodegradable polymers such as polylactic acid (PLA), polyhydroxybutyrate (PHB) and thermoplastic starch (TPS) in the recycled PP were analyzed in this work. Thus, recycled PP was blended with biodegradables polymers by melt extrusion followed by injection moulding process to simulate the industrial conditions. Then, the obtained materials were evaluated by studding the changes on the thermal and mechanical performance. The results revealed that the vicat softening temperature is negatively affected by the presence of biodegradable polymers in recycled PP. Meanwhile, the melt flow index was negatively affected for PLA and PHB added blends. The mechanical properties were affected when more than 5 wt.% of biodegradable polymers were present. Moreover, structural changes were detected when biodegradable polymers were added to the recycled PP by means of FTIR, because of the characteristic bands of the carbonyl group (between the band 1700–1800 cm−1) appeared due to the presence of PLA, PHB or TPS. Thus, low amounts (lower than 5 wt.%) of biodegradable polymers can be introduced in the recycled PP process without affecting the overall performance of the final material intended for several applications, such as food packaging, agricultural films for farming and crop protection.
Effect of Oxygen Partial Pressure on the Phase Stability of Copper–Iron Delafossites at Elevated Temperatures
Authors: Stöcker Thomas , Moos Ralf
Published: October 2018

Oxide-based materials are promising candidates for use in high temperature thermoelectric generators. While their thermoelectric performance is inferior to commonly used thermoelectrics, oxides are environmentally friendly and cost-effective. In this study, Cu-based delafossites (CuFeO2), a material class with promising thermoelectric properties at high temperatures, were investigated. This work focuses on the phase stability of CuFeO2 with respect to the temperature and the oxygen partial pressure. For this reason, classical material characterization methods, such as scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, were combined in order to elucidate the phase composition of delafossites at 900 °C at various oxygen partial pressures. The experimentally obtained results are supported by the theoretical calculation of the Ellingham diagram of the copper–oxygen system. In addition, hot-stage X-ray diffraction and long-term annealing tests of CuFeO2 were performed in order to obtain a holistic review of the phase stability of delafossites at high temperatures and varying oxygen partial pressure. The results support the thermoelectric measurements in previous publications and provide a process window for the use of CuFeO2 in thermoelectric generators.