bluuebunny/crossref_metadata_2025 huggingface dataset:
Softening Behavior and Mechanism of Laser Rapid Forming Ti-6Al-4V Alloy Deformed at the High Temperature
Authors: Sun Kun , Xiang Wenli , Xu Yuan , Shu Xinzhu
Published: October 2020

Using the gleeble-1500 thermal simulator, the high temperature quasi-static compression experiment on cylindrical samples of Laser Rapid Forming Ti-6Al-4V(LRF TC4) titanium alloy have been conducted. Softening behaviour and mechanism of LRF TC4 alloy deformed at different high temperatures were investigated by means of optical microscope (OM) and transmission electron microscope (TEM). It shows that, the strength of LRF TC4 was observably reduced with the rise of the deforming temperature, showing stronger thermal softening effect and superplasticity ability. Microstructure analysis on the samples deformed at the temperature from 400°C to 900°C showed that the original acicular microstructure of LRF TC4 has two significant changes: Acicular microstructure bents at the temperature from 400°C to 600°C, while acicular microstructure bents drasticly, fragmented, spheroidized at the temperature from 700°C to 900°C. No matter bending, fragmentation, or spheroidizing of acicular microstructure, stress in the deformed sample is released. Therefore, these three factors and their superimposition action were the source of thermal softening of LRF TC4 deformed at the high temperature.
Study on Bearing Capacity Performance and Influence Factors of Phyllite Soil Blended with Red Clay
Authors: Zhao Xiushao , Fu Zhitao , Yang Qijing , Geng Daxin , Wang Zhiyao
Published: October 2020

Phyllite soil has low bearing capacity and can not meet the mechanical properties of subgrade, so it is proposed to use special soil (red clay) to reinforce and improve phyllite soil. The shear strength indexes of unsaturated and saturated mixed soil were obtained by shear strength tests, and the ultimate bearing capacity calculation model was established based on shear strength indexes and plate load test. The calculation results show that the reduction of the ultimate bearing capacity can exceed 50% after saturation. According to the detection indexes of foundation coefficient (K
30) and the requirement of medium and long-term bearing capacity in the subgrade code, the minimum blending ratio of red clay in different filling layers of subgrade was obtained through comparison, which can provide a basis for improving special soil with special soil.
Synthesis and Characterization of Phthalocyanine Polymer Towards Nonlinear Optical Applications
Authors: Wang Jihua , Duan Qian
Published: October 2020

In the present study, linear poly(methyl methacrylate161-co-phthalonitrile1.5) (P(MMA161-co-CPMA1.5)) polymer was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. Then the P(MMA161-co-CPMA1.5) polymer followed by macrocyclization reaction to form poly(methyl methacrylate167-co-zinc phthalocyanine1.1) (P(MMA167-co-ZnPc1.1)) polymer. The P(MMA167-co-ZnPc1.1) polymer was characterized by fourier transform infrared, nuclear magnetic resonance, ultraviolet-visible absorption. The nonlinear optical properties of the P(MMA167-co-ZnPc1.1) polymer were investigated by using the Z-scan technique at 532 nm with 7 ns laser pulses. The results revealed that the P(MMA167-co-ZnPc1.1) polymer exhibited excellent reverse saturable absorption (RSA) performance.
Preparation and Properties of Oriented Silicon Steel Insulation Coating with Repair Function
Authors: Huang Zhenxin , Wu Lin , Liu Ying , Hu Ya , Zhang Rui , He Yuxin , Chen Jintao , Wang Ke , Yang Xiaoyu
Published: October 2020

In order to improve the comprehensive performance of oriented silicon steel insulation coatings and repair surface defects, an insulating coating for oriented silicon steels with repair function was prepared. The repair function was investigated by a simulation experiment. Adhesion and magnetic characteristics were measured. Corrosion resistance was tested by neutral salt spray test. The structure of the insulating coating was characterized by infrared spectroscopy. Results exhibit that the coating has good performance and long service life. The surface is smooth, bright and even, the adhesion is A and the coating is able to embellish the defects of crystal exposing on the matrix layer. There is no corrosion occurred after 24h salt spray test; the magnetic induction intensity B800 is 1.81T, which meets the technical requirements of domestic steel mill products.
Early-age Shrinkage-induced Cracking Prevention of Cast-in-place Concrete of Subway Station under Marine Environmental Conditions
Authors: Liu Quanwei , Zhang Jian , Xu Wen , Wang Yujiang , Wang Hongbo , Wen Quan
Published: October 2020

Early-age cracking and leakage phenomena has became a serious problem for cast-in-place concrete of underground station in marine environment, in the present work, an anti-cracking admixture (HME-V) with temperature rise inhibition and micro-expansion properties were adopted to mitigate shrinkage cracking risk. Results indicated that the usage of HME-V exhibits larger expansion behavior not only at temperature rise period but also at temperature fall period, leading to the compensation of real-time shrinkages in concrete. Meanwhile, the early adiabatic temperature rise rate can be significantly reduced with no influence on final value. As a result, the temperature peak value and average cooling rate of the field concrete were decreased by 21.0% and 24.2% respectively. In addition, the usage of HME-V displays considerable impact on early-age compressive strength and but made no difference to the later ones. As no visible cracks and water leakage were observed in the sidewall structure, this work may prove a feasible approach to prevent early-age shrinkage crack of cast-in-place concrete used for underground station.
Effect of Steel Fiber on Fluidity and Compressive Strength of Ultra-high Performance Concrete
Authors: Wang Yanan , Yu Genshe , Wang Jue , Liu Yonghui
Published: October 2020

The influence of steel fiber content on concrete fluidity and compressive strength was studied through the slump, expansion and compressive strength tests of ultra-high performance concrete specimens with different steel fiber content. The results show that the fluidity of concrete decreases obviously with the increase of steel fiber content, but this situation can be improved by adjusting the amount of water-reducing agent. With the increase of steel fiber content, concrete compressive strength increases obviously, but the higher the steel fiber content is, the better. When it exceeds a certain value, concrete compressive strength begins to decline.
Elastic Solution of Stress Boundary Problem for Orthotropic Materials
Authors: Jia Purong , Suo Yongyong , Jia Cheng
Published: October 2020

The elastic solution of common stress boundary problem is discussed for the plate with orthotropic materials. Essential equations are introduced on the basis of linear elastic mechanics and complex variable method. The complex variable functions including the material parameters are analyzed for solving the partial derivation equation and to meet the needs of the stress boundary conditions. By constructing new stress functions, the mechanic analysis of the orthotropic plate is carried out, and also the stress boundary problem is resolved. The general expressions of the stress fields are determined finally.
Study on Energy-Storing Building Materials Made of Paraffin/Montmorillonite Composites
Authors: Zhou Dunbai , Ji Fenglong
Published: October 2020

Phase change materials (PCM) are promising in the application for reducing building energy consumptions and increasing thermal comfort. However, PCM have not been used as building materials extensively. A major technical hindrance for the applications of PCM in building materials is the packaging of PCM. The strategies for the packaging of PCM in building materials reported in the previous studies were mostly unsatisfactory because of the disadvantages such as complex proccesses, high cost or poor packing effectiveness, etc. This study presented a novel simple and low-cost way to make energy-saving building materials with PCM. In this study, a composite containing PCM was developed with montmorillonite (MMT) and paraffin via a simple and low-cost route. Through the selection of appropriate raw materials and with the vigorously mixing using a high-shear mixer, the PCM/MMT composites were prepared simply. The thermal properties of the PCM/MMT composites were investigated by differential scanning calorimetry (DSC). Based on the thermal properties and packing effectiveness the weight ratio of PCM: MMT = 5:4 was determined as the appropriate composition of the PCM/MMT composites. As compared with the PCM composites made of organically modified MMT, the PCM/MMT composites prepared in this study exhibited higher compression strength. The thermal conductive performance of the wallboards made of the PCM/MMT composites and the ordinary wallboards was simulated through numerical simulation. The experimental systems were also set up for testing the energy-saving characteristic of the building materials containing the PCM/MMT composites under both laboratorial conditions and natural outdoor conditions The numerical simulation as well as the experimental results indicated that the wallboard made of the PCM/MMT composite could effectively reduce the temperature fluctuation and would be favorable for keeping room in a comfortable temperature range. Hence the PCM/MMT composites might be promising for developing high-performance thermal regulating building materials with low-cost.
Review on Inorganic Materials Modified Sulfonated Poly(ether ether ketone)Membranes—Used as Proton Exchange Membranes
Authors: Gao Xiaomin
Published: October 2020

As proton conductor and fuel separator, the proton exchange membranes (PEMs) are important electrolyte for the proton exchange membrane fuel cell (PEMFC). The Nafion membranes, used as traditional PEMs, are limited by some disadvantages, so the sulfonated poly(ether ether ketone) (SPEEK) with good comprehensive properties is expected to replace the Nafion. In this paper, the SPEEK composite membranes modified by inorganic materials are summarized. The results show that the SiO2, CNTs and some other inorganic materials are prospective candidates for high-performance SPEEK membranes.
Dynamic Impact Damage of Oil and Gas Pipelines
Authors: Nie Hailiang , Ma Weifeng , Sha Shengyi , Ren Junjie , Wang Ke , Cao Jun , Dang Wei
Published: October 2020

Dynamic impact damage is one of the main causes of Oil and Gas pipeline failure, but there is no systematic research method and achievement on pipeline dynamic impact damage at present. As the weak link of pipeline, girth weld is the most important research object in practical engineering application, so it is urgent to study the damage behaviour of pipeline girth weld under dynamic impact load. This paper reviews the experimental technology of split Hopkinson Pressure Bar in the field of dynamic impact mechanics, the theoretical knowledge of stress wave propagation theory, dynamic mechanics and damage mechanics, as well as the finite element simulation analysis method, explains the application of theory and technology in practical engineering, introduces the research status of mechanical behaviour of pipeline girth weld under dynamic impact load, and looks forward to the theoretical and technical trend of dynamic impact mechanics of pipeline girth weld. It lays a foundation for the dynamic impact safety evaluation and the establishment of protection system of pipeline girth weld.
Flow Stress Evolution of P/M Nickel-base Superalloy During High-temperature Plastic Deformation
Authors: Fang Shuang , Zhang Mincong , Dong Yunpeng
Published: October 2020

In this work, the use of scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction technique and experimental study of the nickel-base superalloy FGH96 recrystallization behavior of alloy. Through experimental study found that the thermal deformation, FGH96 alloys under different plastic deformation at high temperature deformation process parameters, mainly dynamic softening and strain hardening in two stages.
Experimental Study on the Preparation of Recycled Fine Aggregate
Authors: Zhong Weiqiu , Li Wuxu , Xiong Shengyuan , Zhou Aijun , Li Lintao
Published: October 2020

In this paper, the waste concrete is used to produce recycled fine aggregate, and then different mixing quantities are used to produce ordinary mortar by replacing artificial sand. The paper makes relevant studies on the influence of the recycled fine aggregate quantity on the performance of ordinary mortar. The studies show that it is feasible to produce ordinary mortar with a certain amount of recycled fine aggregate instead of artificial sand, which can meet the requirements of relevant standards, specifications and engineering.
Optimization of the Extraction Process of Anti-Vibrio parahaemolyticus Active Substances from Coptidis Rhizoma (Huanglian)
Authors: Wang Xintong , Guo Siya , Zhang Zongyi , Xu Qian , Guo Lei
Published: October 2020

The purpose of this study is to optimize the extraction process of the anti-Vibrio parahaemolyticus active substances from Coptidis rhizoma (Huanglian). Single factor experiment, Box-Behnken experimental design combined with response surface methodology were used to optimize the extraction process. The obtained optimal extraction conditions followed as: extraction solvent is 100% methanol, extraction temperature of 86 °Q liquid/material ratio of 21 mL/g’ extraction time of 116 min. The actual value of the inhibition zone of the extract can reach 15.62±0.16 mm, which is not significantly different from the predicted value of 15.12 mm. This indicates that the above method is feasible to optimize the extraction process of the anti-V. parahaemolyticus active substances from Coptidis rhizoma.
Reason of Intermediate Casing Wear in Ultra-deep Wells in China’s Tarim Oil Field
Authors: Ma Chao , Gao Baokui , Wang Jieli , Hu Tianxiang , Chen Xingwang
Published: October 2020

The intermediate casing wear is often found in ultra-deep wells in Tarim area. This phenomenon usually leads to many troubles in following well construction. By investigating 9 wells in this area that have severe intermediate casing wear, it is found that all casings are badly cemented, and the reason of casing wear is supposed to be helical buckling of casing string. In order to verify this judgment, geometry relationship among enlarged wellbore, buckled casing string and drill pipe joint are studied. When helical buckling occurs in casing string, apparent inner diameter of casing is usually smaller than the outer diameter of drill pipe joint. Therefore, rotating drill pipe joints wear casing inner surface continuously and forms a spiral scratch. Key factors that affect casing wear, such as wellbore enlargement rate, casing dimensions, casing centralizer and diameter of drill pipe joint, are discussed.
Effect of Grinding Parameters on the Hardness Penetration Depth of the Steel GCr15 in Internal Grind Hardening Process
Authors: Hou Dapan , Gao Shunxing , Liu Judong , Huang Songwei
Published: October 2020

This paper discusses the effects of the depth of cut (ap
), the workpiece speed (vw
) and the grinding wheel speed (vs
) on the structure and hardness of the grind hardening layer on the steel GCr15. It was found that the completely hardened zone of the internal grind-hardened layer on the steel GCr15 mainly contains needle-shaped martensite and a very low amount of carbides and retained austenite. The grinding parameters have no significant effect on the martensite microstructure and hardness of the high-hardness zone in the internal grind-hardening process. An increase of the depth of cut and the grinding wheel speed or a decrease of the workpiece speed, leads to a thicker grind-hardening layer. From the viewpoint of increasing the hardness penetration depth, a larger the depth of cut and the grinding wheel speed and a smaller the workpiece speed should be selected, under the internal grind-hardening experimental conditions.
Influences of Casing Wear on Mechanical Behavior of Packer Element
Authors: Wang Jieli , Gao Baokui , Ma Chao , Hu Tianxiang , Chen Xingwang
Published: October 2020

Packer element is made of hyperelastic rubber, and its mechanic performance determines the packer’s sealing effect. In oil field, casing wear is often found and in some special circumstance the packer has to set at worn casing section. In order to study the effect of casing wear on element mechanical behavior, contact pressure between element and casing with crescent-shaped wear notch is calculated by use of commercial ANSYS software. The influences of notch depth and diameter of drill pipe joint on contact pressure are discussed in detail. The results show that the contact pressure has a saddle-shaped distribution along axial direction similar to that without wear. But minimum contact pressure decreases rapidly when the notch depth increases. And a larger diameter of drill pipe joint can give rise to lower contact pressure near the notch.
Microstructure and Impact Toughness of X70–L245 Butt Girth Weld in Natural Gas Station
Authors: Ren Junjie , Ma Weifeng , Hui Wenying , Tong Ke , Nie Hailiang , Wang Ke , Dang Wei , Cao Jun
Published: October 2020

At present, the numerical simulation and safety evaluation of girth welds are based on the properties of tubular materials, which cannot truly reflect the properties of girth welds. Based on the investigation results of girth weld in the station, this paper took X70 (21mm) and L245 (12mm) joints with large material and wall thickness gap in the station as research objects, prepared girth weld according to the welding process in the project site, and studied the structure and impact toughness of the joints. The microstructure of weld zone was analyzed by optical microscope. Charpy impact toughness increased from the center of weld to both sides, and the center of weld was the lowest. On X70 side, the impact toughness of FGHAZ is the highest and the impact energy is about 200 J, which is significantly higher than the weld center. The impact toughness near the fusion line on side L245 is the highest, but significantly smaller than that on side X70. Grain refinement, interlacing structure and M/A structure are conducive to the improvement of impact toughness. In this kind of girth weld, the center of the welding seam is the weakest area, and the X70 side has a significantly higher toughness.
Recovering Vacuum Drying Exhaust Latent Heat by Steam Recompression with a Jet Pump
Authors: Li Xuanyou , Gao Ling , Sun Rongfeng , Yang Liguo
Published: October 2020

Recovery of latent heat is one of the most efficient methods to reduce drying energy consumption. This paper presents a system to recovery exhaust latent heat for vacuum drying. Replacing water with heat conduct oil, a hydraulic Jet was employed to evacuate the dryer and compress the exhaust vapour. The heated vapour, which is increased its temperature and pressure by means of recompression, was transferred to the vacuum dryer as the heat source through a heat pipe. This design was confirmed by a series of experiments with oil sludge.
Design and Realization of a Special Robot Manipulator
Authors: Tan Yingqi
Published: October 2020

A structure of small special robot manipulator is designed by using the parallelogram lifting device. The stiffness and strength for the manipulator are both improved to meet indicators and functions of the performance by design and calculation. The grasping range of the manipulator is enlarged and the grasping force is enhanced by comparing different materials according to the simulation on Solidworks. The object can be grasped accurately by the manipulator. This kind of structure design provides a reference for a robot manipulator.
Research on the Technology of Integral Water Searching and Plugging for Two-Stage Casing Gas-Lift Wells in Sudan Oilfield
Authors: Xu Dekui , Cai Meng , Xu Hao , Liu Chongjiang , Lin Zhongchao , Song Xingliang , Zhao Lichuan , Sun Jiang , Gao Fei , He Qing , Zhang Pingan , Liu Yun , Zhao Xuyang , Liu Yuchuan , Wang Pengcheng
Published: October 2020

The combination structure of

9

5
8

”

and

5

1
2

”

casing is used in some gas-lift wells in Sudan Oilfield. The existing mechanical water searching and plugging technology cannot meet the technical requirements of this type of well, so a integral water searching and plugging string for two-stage casing gas-lift well is developed. The string is composed of two kinds of packers and one kind of regulator. The two kinds of packers are set by hydraulic pressure synchronously to seal the layers of two kinds of casing. After the packers are set, the steel wire is used to fish and drop the blanking plug and search the water layer by layer to realize the adjustment of production layers. This process string has the characteristics of accurate water layer searching, reliable sealing, dynamic adjustment, etc. The string can realize water searching and plugging for two-stage casing wells by one trip. The string has been applied in well JS-2 in Sudan. After adjustment and plugging, the water cut is 25.6% lower than before. The effect of water control and oil production increase is significant, and the production life of the well is prolonged.
Flow Behaviour and Microstructure Evolution of 2196 Alloy during Isothermal Compression
Authors: Cao Hailong , Tian Yuxing , Du Kang , Niu Guanmei , Liu Cheng
Published: October 2020

The isothermal compression test of 2196 alloy was carried out by Gleeble-1500 isothermal simulator with deformation temperature from 430°C to 500°C and strain rate from 0.01s−1 to 10s−1. The results show that the stress-strain curves are stable flow for the most deformation parameters. These stable flow exhibit a good ductility of 2196 alloy, also confirmed by no crack on the edge of the compressed samples. The constitutive equation is established using exponential relationship and the average activation energy Q is189.2kJ/mol. Microstructure observation show that very few recrystallized grains at original grain boundaries and triple junctions for the all deformation parameters. It is clear that the dynamic recrystallization is difficult for the 2196 alloy suffered common thermal deformation, while the main microstructure evolution mechanism is dynamic recovery. At the same deformation temperature, the recrystallization fraction decreases with increased strain rate, while the proportion of subgrain increases. The recrystallization and dynamic recovery are two main factors for the microstructure characteristics.
Study of surface chemical composition of oxide nanostructures by X-ray photoelectron spectroscopy
Authors: Nalimova S S , Shomakhov Z V , Bobkov A A , Ryabko A A , Kalazhokov Z Kh , Maximov A I , Moshnikov V A
Published: October 2020

Zinc oxide and zinc stannate nanowires were synthesized by hydrothermal method. Zinc oxide nanowires were doped by iodine. The formation of multicomponent and doped oxides was studied by X-ray photoelectron spectroscopy. It was found that formation of zinc stannate from zinc oxide nanowires occurs in 1 hour. The percentage of OH-groups increases on the surface of zinc oxide nanowires as a result of doping by iodine.
Investigation and identification of the spectral composition of noise in the accelerometer channel of the navigation module
Authors: Pavlov D V , Petrov M N
Published: October 2020

The paper studies and measures the characteristics of random error components of the output signal in the accelerometer channel of an inertial navigation module, in which the MMA7331LT accelerometer is used. The spectral composition of the random components of the errors of the accelerometer was estimated using the Allan method of aeration. The calculated values of the coefficients characterizing the intensity of various types of noise are obtained.
On the program implementation of a simple Markov homogeneous random search algorithm of an extremum with Cauchy distributions
Authors: Tikhomirov A S
Published: October 2020

A program that implements a simple Markov homogeneous random search algorithm of an extremum with Cauchy distributions is presented. This program allows solving a fairly wide class of problems of finding the global extremum of an objective function with a high accuracy.
Modeling non-standard probability laws based on a mixture of truncated distributions
Authors: Tokmachev M S
Published: October 2020

A method for modeling probability distributions is presented using two operations: truncating multiple base distributions in various ways, and converting them to a mixture. The normal distribution is considered as the basic one. The use of truncations and varying the truncation intervals of the mixture components lead to distributions with a complex non-standard configuration, in particular, asymmetric and multi-vertex ones. Distributions simulated in this way are used as theoretical ones in computer programmed fitting to sample data with a non-standard structure. The conditions for the continuity of the final distribution are obtained. The construction algorithm allows implementing other distributions.
Quantum-mechanical calculations of mixing enthalpy of the bcc phase of the Fe-Mo system for the ground state
Authors: Udovsky A L , Vasilyev D A
Published: October 2020

The structural energies, formation enthalpies and bulk elastic moduli of bcc iron and molybdenum in the Fe – Mo system, are calculated for further use in the calculations of the bcc / bcc + Fe2Mo Laves phase boundary at low (room) temperatures.
Temperature dependence of the catalytic activity of promising nanomaterials based on biopolymers: lipase and chitosan
Authors: Zaitsev S Yu , Zaitsev I S
Published: October 2020

A study of the interactions of porcine pancreatic lipase (PPL) with chitosan is the most interesting and important in order to regulate the enzymatic properties of the future nanomaterials based on these biopolymers. A decrease in catalytic activity of pure PPL towards triacetin during prolonged operation and storage is shown: activity decreases by 24.1% within 1 hour and by 54.0% - in the case of the lipase storage in solution for 1 month. The optimum temperature of 40°C was determined for samples of pure PPL, whereas a small shift from 40° to about 45°C - for PPL:Chit complex (50:1). The catalytic activity of free PPL at 40°C was the highest (as compared to lower and higher temperatures) and stable for 20 min. However, the dynamics showed a pronounced decrease to almost 2 times within further 30-60 minutes. In contrast, at 40°C the catalytic activity of PPL in complex with chitosan (50:1) stabilized at almost the same level (although it was lower than the activity of free PPL in the first 30 minutes of measurement). The PPL:Chit complex can be considered as promising catalytic nanomaterials (based on chitosan and lipase) for further applications.
Using the same type of IP-cores in the Virtex-6 family FPGA-architecture for distributed image processing
Authors: Zakharov V M , Shalagin S V , Eminov B F
Published: October 2020

Distributed image processing in real time is a relevant task. An effective solution to this problem at the hardware level is possible on the basis of creating prototypes of devices on FPGA. In this regard, the paper solves the problem of distributed computation of two-dimensional fast Fourier transform (TDFFT) based on the same type of IP-cores implemented in the architecture of the Virtex-6 family_FPGA-architecture. The possibility of distributed implementation of each of the stages of the TDFFT, performed using four transformations of the “butterfly” type_(TrB) over four elements of the processed data array, is shown. When using a specialized CAD-system, estimates of the time and hardware complexity of the IP-core implementing TrB are_obtained. The estimated operating frequency of this_IP-core is approximately 108 MHz. Hardware complexity estimates by the number of configurable elements involved in the Virtex-6 family_FPGA-architecture are determined. TrB must be performed over an_array of N
2 elements a · N
2/4 once, where a = log2
N is the number of TDFFT stages, and N = 2
k
. The ability to parallelize the specified operations at each of a stages by using_IP-cores that implement four TrB is shown. The results can be used to estimate hardware and time costs for distributed TDFFT execution over a square data array N × N - dimension.
Indirect, experimental constraints of (n,γ) reaction rates for the i- and r-process
Authors: Larsen A. C. , Spyrou A. , Guttormsen M. , Liddick S. N.
Published: October 2020

Our Universe contains a large variety of chemical elements, for which only the lightest ones were produced during the Big Bang. To make elements heavier than iron, neutron-capture processes are called for, in particular the slow and the rapid neutron-capture processes. Recently, a so-called intermediate neutron-capture process has received a lot of attention as more and more evidence points towards its existence. Both the intermediate and rapid neutron-capture processes involve very neutron-rich nuclei, for which there exist little or no data on their neutron-capture cross sections. Here we present an experimental method to indirectly constrain neutron-capture reaction rates needed for calculating nucleosynthesis yields for the intermediate and rapid neutron-capture processes.
How accurately can the Extended Thomas-Fermi method describe the inner crust of a neutron star?
Authors: Shelley M. , Pastore A.
Published: October 2020

We perform a systematic comparison between the results obtained by solving fully self-consistently the Hartree-Fock-Bogoliubov equations, and those obtained using the semi-classical Extended Thomas-Fermi method, for various Wigner-Seitz cells within the inner crust of a neutron star. The lack of pairing correlations in the semi-classical approach leads to a large discrepancy between the two approaches. This discrepancy is well beyond the error of the quantum-mechanical calculation, and is related to spurious shell effects in the neutron gas.
3. The divine king
Authors: Restall Matthew , Solari Amara
Published: October 2020

“The divine king” begins with a short biography of the Maya k’uhul ajaw (supreme lord or king) known as 18-Rabbit. During the Classic period, rulers were viewed as divine kings or queens, like 18-Rabbit and Lady K’abel (“Waterlily-Hand”). The ancient Maya used a combination of a cyclical calendar and a linear calendar called the “Long Count.” The Maya area experienced regular intrusions from imperial Teotihuacan, often leading to economic and diplomatic partnerships. Most Mayas experienced war in their lifetimes. The “Collapse” at the end of the Classic period could more accurately be called a transition, with major regional variations. Some well-known Maya sites flourished after the Collapse.
3. Saving the center
Authors: Abbott Carl
Published: October 2020

“Saving the Center” looks at the history of central business districts and the initiatives developed to clean up undesirable areas around them, making them more attractive to businesses and the middle classes. Planners tackling this issue adopted a highly targeted approach, often letting stable or vibrant areas fall into disuse as a result. Critics of this top-down approach included the architecture writer Jane Jacobs, who called on planners to work on a smaller scale and reprioritize public spaces and the existing social fabric. The revitalization of London’s formerly derelict Docklands is a prototype for postindustrial expansion that has been reproduced successfully elsewhere in the world.
7. Unnatural disasters and resilient cities
Authors: Abbott Carl
Published: October 2020

How can cities protect themselves from social and political conflict, and environmental stressors from climate change? “Unnatural disasters and resilient cities” looks at how these threats have affected wealthy and less wealthy cities around the world, showing how communities differ in vulnerability to death, damage, and disruption from these events. Planners working in areas marked by sectarian violence need to be aware of local history and sensitivities. After disasters, ambitious plans for remaking cities are rarely implemented. Attempts to remake a city after a disaster, and even protect it from one, are more effective when executed at a local level.
3. Sliminess and stickiness
Authors: McLeish Tom
Published: October 2020

‘Sliminess and stickiness’ examines the molecular origin of ‘stickiness’. It details Hermann Staudinger’s research on ‘double bonds’ and ‘macromolecules’. Understanding the unorthodox properties of the polymer liquid and gel state turned out to be one of the first successes of soft matter science. Staudinger faced a challenge: how much space would a polymer molecule occupy when in solution? Many of the mathematical techniques that had been developed to deal with the quantum mechanics of electrons, photons, and their interaction in solids could be translated into tools for solving polymer problems such as this one. The properties of rubber, and the sticky sliminess of rubbery liquids, are topics which relate to the notion of stickiness.
Introduction
Authors: Young Robert J. C.
Published: October 2020

The Introduction provides an overview of postcolonialism and postcolonial theory. The term ‘postcolonialism’, which began to be used from the 1990s, represents perspectives critical of or resistant to colonialism or colonial attitudes. Anti-colonial thinkers had always insisted that decolonization had to begin with colonized peoples decolonizing themselves mentally from the ways in which they had begun to see things from the perspective of the colonizers. Postcolonialism too is about changing one’s mind-set and values. In a comparable way, ‘postcolonial theory’ involves a conceptual reorientation towards the perspectives of knowledges, as well as needs, developed outside the West.
6. Hybridity
Authors: Young Robert J. C.
Published: October 2020

‘Hybridity’ explains that cultural hybridity can be seen as an expansion of W. E. B. Du Bois’ concept of ‘double consciousness’: a painful incompatibility between how people see themselves and how society sees them only in terms of their race. Nevertheless, this has also formed the basis of the extraordinary cultural creativity of African-Americans. Drawing on cultural memory of their African roots, African-Americans have adapted and transformed aspects of European culture encountered in the US, particularly noticeable in the realm of African-American music. A comparable development of a hybridized culture is considered by tracing the emergence of raï music in 1970s Algeria, following the traumatic experiences of the Algerian War of Independence.
7. The ambivalence of the veil
Authors: Young Robert J. C.
Published: October 2020

‘The ambivalence of the veil’ explores the relationship between Western and Muslim worlds. For many Westerners, nothing symbolizes the differences more than ‘the veil’, a shorthand for the many ways in which Muslim women choose to dress, sometimes covering their heads or faces. Today, in Islamic societies, and among many Muslim women in non-Islamic societies, the veil (hijab) has come to symbolize a cultural and religious identity. A pertinent question to ask is how can a 1930s colonial image of an ‘Arab woman’ typifies European stereotypical representations of, and assumptions about, Muslim women even today. This can be contrasted with how men in masks—Batman or the Zapatistas in balaclavas—are considered to exhibit positive forms of masculinity.
American Military History: A Very Short Introduction
Authors: Glatthaar Joseph T.
Published: October 2020

American Military History: A Very Short Introduction outlines the forces shaping the American military for the past 400 years. Since the colonial period, the United States has struggled to balance standing armed forces with citizen soldiers and sailors. Technological developments and two world wars forced the military to embrace professionalism and its increased obligations. The United States emerged from World War II in a strong position but failed to recognize the limits of its power, a legacy that some might say continues. Recent wars highlight some of the problems of a volunteer-dominated force. To succeed, the American military needs improved communication, understanding, and support.
Writing Apartheid: Ethnographic Collaborators and the Politics of Knowledge Production in Twentieth-Century South Africa
Authors: Cabrita Joel
Published: October 2020

Knowledge production in apartheid-era South Africa was a profoundly collaborative process. In particular, throughout the 1930s–1950s, the joint intellectual labor of both Africans and Europeans created a body of knowledge that codified and celebrated the notion of a distinct realm of Zulu religion. The intertwined careers of Swedish missionary to South Africa Bengt Sundkler and isiZulu-speaking Lutheran pastor-turned-ethnographer Titus Mthembu highlight the limitations of overly clear demarcations between “professional” versus “lay” anthropologists as well as between “colonial European” versus “indigenous African” knowledge. Mthembu and Sundkler’s decades-long collaboration resulted in a book called Bantu Prophets in South Africa ([1948] 1961). The work is best understood as the joint output of both men, although Sundkler scarcely acknowledged Mthembu’s role in the conceptualization, research, and writing of the book. In an era of racial segregation, the idea that African religion occupied a discrete, innately different sphere that the book advanced had significant political purchase. As one of a number of African ideologues supportive of the apartheid state, Mthembu mobilized his ethnographic findings to argue for innate racial difference and the virtues of “separate development” for South Africa’s Zulu community. His mysterious death in 1960 points to the high stakes of ethnographic research in the politically fraught climate of apartheid South Africa.
Tracing Lung Cancer Risk Factors Through Mutational Signatures in Never-Smokers
Authors: Landi Maria Teresa , Synnott Naoise C , Rosenbaum Jennifer , Zhang Tongwu , Zhu Bin , Shi Jianxin , Zhao Wei , Kebede Michael , Sang Jian , Choi Jiyeon , Mendoza Laura , Pacheco Marwil , Hicks Belynda , Caporaso Neil E , Abubakar Mustapha , Gordenin Dmitry A , Wedge David C , Alexandrov Ludmil B , Rothman Nathaniel , Lan Qing , Garcia-Closas Montserrat , Chanock Stephen J
Published: October 2020

Epidemiologic studies often rely on questionnaire data, exposure measurement tools, and/or biomarkers to identify risk factors and the underlying carcinogenic processes. An emerging and promising complementary approach to investigate cancer etiology is the study of somatic “mutational signatures” that endogenous and exogenous processes imprint on the cellular genome. These signatures can be identified from a complex web of somatic mutations thanks to advances in DNA sequencing technology and analytical algorithms. This approach is at the core of the Sherlock-Lung study (2018–ongoing), a retrospective case-only study of over 2,000 lung cancers in never-smokers (LCINS), using different patterns of mutations observed within LCINS tumors to trace back possible exposures or endogenous processes. Whole genome and transcriptome sequencing, genome-wide methylation, microbiome, and other analyses are integrated with data from histological and radiological imaging, lifestyle, demographic characteristics, environmental and occupational exposures, and medical records to classify LCINS into subtypes that could reveal distinct risk factors. To date, we have received samples and data from 1,370 LCINS cases from 17 study sites worldwide and whole-genome sequencing has been completed on 1,257 samples. Here, we present the Sherlock-Lung study design and analytical strategy, also illustrating some empirical challenges and the potential for this approach in future epidemiologic studies.
Development and perceived value of a master’s degree in health-system pharmacy administration training
Authors: Colmenares Evan W , McLaughlin Jacqueline E , Morbitzer Kathryn A , Eckel Stephen F
Published: October 2020

Purpose

To describe the development, format, and alumni and employer perceptions of a program combining a master of science (MS) degree with a residency in health-system pharmacy administration and leadership (HSPAL).

A multisite combined MS and HSPAL residency program was developed within the University of North Carolina at Chapel Hill Eshelman School of Pharmacy to increase leadership and management education. The program balances clinical and administrative experiences with didactic courses over 2 years. The program format and perceived value of MS degree training for HSPAL residents had not been previously described in the literature. In an online survey, alumni of the program, as well as their first supervisors after completion of HSPAL training, indicated perceived attainment of the program core competencies and outcomes. Supervisors also indicated that they were more likely to hire MS degree–trained pharmacists for administrative positions.

Conclusion

Didactic training in the form of an MS degree as a part of comprehensive HSPAL residency training is perceived as beneficial by alumni and employers for promoting the development of core leadership and management skills and knowledge.
Development of an innovative delivery system for bacillus Calmette-Guérin bladder administration
Authors: Szewczyk Michael T , Soefje Scott A
Published: October 2020

Purpose

To describe the development of an innovative process to deliver bacillus Calmette-Guérin (BCG) to an offsite urology clinic for bladder instillation.

The use of BCG, a live virus vaccine for treatment of patients with localized cancer of the urinary bladder, has created many logistical problems for hospitals and infusion center pharmacies. Due to its short stability, the drug cannot be made ahead of time and coordination with a patient’s arrival at an infusion site is challenging. This becomes exceptionally challenging when a urology clinic has limited compounding capacity and/or is distant from the site of BCG medication preparation. This article describes an innovative process involving use of closed-system transfer devices (CSTDs) to allow for the administration of BCG in a urology clinic offsite from a medical center’s infusion center facilities.

Conclusion

The use of the CSTD allowed the patients to continue to receive bladder instillations at an offsite urology clinic without significantly disrupting compounding workflow at the small infusion center pharmacy that was the nearest to the clinic.
Procedural technique for hybrid pulmonary valve replacement in infants and small children
Authors: Breatnach Colm R , McGuinness Jonathan , Ng Li Yen , Franklin Orla , Redmond Mark , Nölke Lars , McMahon Colin , Oslizlok Paul , Walsh Kevin , Kenny Damien
Published: October 2020

OBJECTIVES

Hybrid approach to pulmonary valve replacement (PVR) in the paediatric population has been reported, although data in infants and small children are limited. Several strategies are now possible. The aim of this study is to review our hybrid PVR strategy in a complex patient cohort, outlining a variety of approaches employed in our centre.

METHODS

We performed a retrospective review of infants and small children who underwent hybrid PVR between May 2017 and April 2019 in a single tertiary cardiology centre. Medical records were reviewed to ascertain demographic, clinical and outcome data.

RESULTS

Ten patients with a median (interquartile range) age of 1.5 years (1.1–1.9) and weight of 8.8 kg (8–10.6) were managed with hybrid pulmonary valve insertion. Eight patients had perventricular approach (4 sternotomy and 4 subxiphoid) and 2 patients had surgically sutured valve. Six patients underwent cardiopulmonary bypass for associated lesions. Three had insertion of the valve into conduits and 7 were deployed into native right ventricular outflow tracts. The pulmonary valve was successfully inserted in all 10 patients with no mortality. Postprocedural complications included paravalvar leak in 2 patients, suspected endocarditis in 1 patient who developed early valve regurgitation and wound infection in 1 patient.

CONCLUSIONS

Several approaches to hybrid PVR may be employed in small children with a high success rate. Follow-up studies are required to evaluate longer term durability of these approaches compared to standard surgical replacement.
Ascending aorta replacement in patients with coronary ostia localized above the sinotubular junction
Authors: Urbanski Paul P , Irimie Vadim , Diegeler Anno , Morka Aleksandra , Thamm Tarvo , Lehmkuhl Lukas
Published: October 2020

OBJECTIVES

The study objective was to describe the technique and outcomes of original coronary ostial slide plasty in patients with anomalous coronary artery origin (ACAO) localized in the aneurysmal ascending aorta (AA) being replaced because of its isolated pathology and otherwise non-pathological aortic root.

METHODS

A total of 23 patients (median age 52 years) with the ascending phenotype of proximal aorta aneurysm and ACAO of at least 1 coronary artery localized in the AA being replaced underwent ostial slide plasty to transpose the ACAO to the respective sinus of Valsalva and, consequently, to allow an AA replacement with placement of the proximal anastomosis at the level of the sinotubular junction (STJ). In 15 patients, the aortic valve was bicuspid, and all but 3 patients presented with a relevant valve defect. In addition to remodelling the STJs (all patients), valve-sparing repair or replacement was performed in 12 and 8 patients, respectively.

RESULTS

No patient died during the entire follow-up (median 72, range 3–183 months). One patient required replacement of a recurrently insufficient valve that was repaired primarily using cusp patch plasty, but there were no further cardiac reoperations nor any re-interventions on the proximal aorta, aortic valve and/or coronary artery ostia. Two patients received peripheral coronary stents (8 and 7 years after surgery, respectively) due to coronary heart disease.

CONCLUSIONS

Transposition of the ACAO from the replaced AA into the normal sinus of Valsalva using the ostial slide plasty offers a simple and safe surgical option enabling a recreation of a durable STJ at the level of the anastomosis between the root and the aortic graft.
Vaccines for multidrug resistant Gram negative bacteria: lessons from the past for guiding future success
Authors: López-Siles Mireia , Corral-Lugo Andrés , McConnell Michael J
Published: October 2020

Antimicrobial resistance is a major threat to global public health. Vaccination is an effective approach for preventing bacterial infections, however it has not been successfully applied to infections caused by some of the most problematic multidrug resistant pathogens. In this review, the potential for vaccines to contribute to reducing the burden of disease of infections caused by multidrug resistant Gram negative bacteria is presented. Technical, logistical and societal hurdles that have limited successful vaccine development for these infections in the past are identified, and recent advances that can contribute to overcoming these challenges are assessed. A synthesis of vaccine technologies that have been employed in the development of vaccines for key multidrug resistant Gram negative bacteria is included, and emerging technologies that may contribute to future successes are discussed. Finally, a comprehensive review of vaccine development efforts over the last 40 years for three of the most worrisome multidrug resistant Gram negative pathogens, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa is presented, with a focus on recent and ongoing studies. Finally, future directions for the vaccine development field are highlighted.