bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustainability evaluation for a circular maize-pig system driven by indigenous microbes: a case study in Northeast China
Authors: Xu Yinan , Li Panfeng , Gao Youhui , Li Yueming , Li Shijie , Li Yunfeng , Sui Peng , Wang Xiaofen , Gao Wangsheng , Chen Yuanquan
Published: May 2022

Sustainable agricultural development is a topic of global concern aiming at satisfying food demand of the growing population while reducing impact on environment. Circular agriculture has become a promising development pattern with the advantages of complementing environmental resources, replacing feedback from outside system, and processing waste of bottom of system, etc. This study combined economic analysis, life cycle assessment and emergy accounting to evaluate sustainability of an integrated maize-pig system (IS) driven by indigenous microbes in Northeast China, compared with separated maize and pig system (SS). IS reduced input of concentrate feed, coal, vaccines, disinfectants, fertilizer and labor by 14.35%, 100%, 46.11%, 100%, 60.1% and 60.8% driven by indigenous microbes. Economic analysis results showed that IS has 82.88% higher profit than that of SS. The sum of potential environmental impacts of IS was lower than SS for 80.65% according to lifecycle assessment. The emergy results revealed that IS performed better sustainability. Internal feedback emergy for fertilizer and local resources for maize straw increasing of IS significantly improved emergy efficiency. The reduction resulted in nonrenewable resources decreased 33.01% than that of SS, and increased renewable resources by 67.81%, which reduced environmental load ratio of IS by 60.08% of IS. Meanwhile, these factors were the primary factors generating higher sustainability of IS. Overall, the integrated maize-pig system driven by indigenous microbes in this study can effectively alleviate the problems caused by agricultural waste and promote sustainable agricultural development.
Thermoelectric effects and applications: an advanced physics laboratory experiment
Authors: Aqra R , AbualRob K , Jaeger H , Eid K F
Published: May 2022

We developed a simple, inexpensive undergraduate laboratory experiment covering concepts and applications related to thermoelectric effects. Students use commercially available thermoelectric plates for producing electric current or for cooling and heating, then utilize them to perform experimental investigations that involve cooling. These investigations include studying supercooling and flash-freezing of water, as well as the temperature dependence of the resistivity of metals and semiconductors. The experiment allows students to easily add more components to investigate additional phenomena, thus lending itself as a potential open-ended ‘final project’ in the lab. The activities emphasize experiment design and scientific investigation. They also develop some of the main goals of advanced physics laboratories, such as the exposure to new technologies and experimental skills, data collection and automation/control, as well as data analysis and the clear communication of the results. This experiment can be integrated into the physics curriculum of electronics or advanced laboratory courses at the sophomore or higher levels.
Broadband achromatic flexural wave Mikaelian lens for high resolution focusing
Authors: Chen Jin , He Xudong , Chen Mingji , Liu Yongquan
Published: May 2022

Conformal transformation method (CTM) has been extensively applied to control propagation of electromagnetic waves and acoustics waves due to the form-invariant property of Maxwell equations and acoustic equations. However, CTM’s application in elastic waves is rarely reported due to the governing equation of elastic waves do not have form invariant property. In this paper, through igniting evanescent waves at the interface of conformally mapped Mikaelian lens with hyperbolic secant refractive index profile, CTM is successfully used to achieve highly efficient (above 75%) broadband (30−80 kHz) achromatic high-resolution flexural wave focusing in thin plate with full width at half maximum (FWHM) around 0.2λ. The proposed Mikaelian lens is designed by linking refractive index with the thickness in plates. Simulated results agree well with theoretical prediction. This high performance for flexural wave focusing could be used for energy harvesting and medical imaging.
Ultra-wideband Luneburg lens with high performance based on gradient metamaterials
Authors: Chen Jin , Chu Hongchen , Huang Yixing , Lai Yun , Chen Mingji
Published: May 2022

Based on the perspective of a wide scanning range and ultra-broad bandwidth, Luneburg lenses are highly anticipated to be an outstanding option for multibeam radiation. However, owing to the lack of low-loss continuously varying permittivity materials, the practical application of Luneburg lenses is far below the expected level. In this paper, an ultra-wideband planar Luneburg lens (PLL) is proposed. Due to the novel design of an all dielectric lightweight radially symmetric periodic gradient metamaterial, the presented lens is able to yield highly directional emission with side lobes all below −8 dB and achromatic sub-diffraction focusing with full width at half maximum about 0.4λ from 4 GHz to 22 GHz. The prototype of the lens is manufactured by computer-numerical controlled machining. The measured data of the near field and far field agree well with that of the simulated data, verifying the effectiveness of the proposed design methodology. The superiority of the presented approach to design a Luneburg lens is demonstrated. Therefore, the PLL has the advantages of being lightweight, with a compact structure, low profile, ultrabroadband function, high resolution, and convenient fabrication, giving it great potential to be practically deployed.
Phase behaviour of ammonium bromide-d
4 under high pressure and low temperature; an average and local structure study
Authors: Funnell Nicholas P , Bull Craig L , Hull Stephen , Ridley Christopher J
Published: May 2022

We revisit the pressure-induced order–disorder transition between phases II and IV in ammonium bromide-d
4 using neutron diffraction measurements to characterise both the average and local structures. We identify a very sluggish transition that does not proceed to full conversion and local structure correlations indicate a slight preference for ammonium cation ordering along ⟨110⟩ crystallographic directions, as pressure is increased. Simultaneous cooling below ambient temperature appears to facilitate the pressure-induced transition. Variable-temperature, ambient-pressure measurements across the IV → III → II transitions show slower conversion than previously observed, and that phase III exhibits metastability above ambient temperature.
PDA modified NIR-II NaEr0.8Yb0.2F4 nanoparticles with high photothermal effect
Authors: Zhan Weifan , Zhao Bin , Cui Xiaoxia , Liu Junsong , Xiao Xusheng , Xu Yantao , She Shengfei , Hou Chaoqi , Guo Haitao
Published: May 2022

Polydopamine (PDA)-modified NaEr0.8Yb0.2 F4nanoparticles were synthesized, with strong NIR-II emission, quantum yield of 29.63%, and excellent photothermal performance. Crystal phases and microstructures are characterized. Optical properties such as absorption, NIR-II emission, and light stability are studied, and the luminescence mechanism is discussed in detail. Key factors in NIR-II imaging were evaluated in fresh pork tissue, including penetration depth, spatial resolution, and signal-to-noise ratio (SNR). A high penetration depth of 5 mm and a high spatial resolution of 1 mm were detected. Mice are imaged in vivo after intravenous injection. Due to the accumulation of nanoparticles in the liver, high image quality with an SNR of 5.2 was detected in the abdomen of KM mice with hair. The photothermal conversion effect of PDA-modified NPs was twice that of the reported material. These NIR-II nanoparticles have superior optical properties, high photothermal efficiency and low cytotoxicity, and are potential fluorescent probes for further disease diagnosis and treatment.
Joint synthesis and registration network for deformable MR-CBCT image registration for neurosurgical guidance
Authors: Han R , Jones C K , Lee J , Zhang X , Wu P , Vagdargi P , Uneri A , Helm P A , Luciano M , Anderson W S , Siewerdsen J H
Published: May 2022

Objective. The accuracy of navigation in minimally invasive neurosurgery is often challenged by deep brain deformations (up to 10 mm due to egress of cerebrospinal fluid during neuroendoscopic approach). We propose a deep learning-based deformable registration method to address such deformations between preoperative MR and intraoperative CBCT. Approach. The registration method uses a joint image synthesis and registration network (denoted JSR) to simultaneously synthesize MR and CBCT images to the CT domain and perform CT domain registration using a multi-resolution pyramid. JSR was first trained using a simulated dataset (simulated CBCT and simulated deformations) and then refined on real clinical images via transfer learning. The performance of the multi-resolution JSR was compared to a single-resolution architecture as well as a series of alternative registration methods (symmetric normalization (SyN), VoxelMorph, and image synthesis-based registration methods). Main results. JSR achieved median Dice coefficient (DSC) of 0.69 in deep brain structures and median target registration error (TRE) of 1.94 mm in the simulation dataset, with improvement from single-resolution architecture (median DSC = 0.68 and median TRE = 2.14 mm). Additionally, JSR achieved superior registration compared to alternative methods—e.g. SyN (median DSC = 0.54, median TRE = 2.77 mm), VoxelMorph (median DSC = 0.52, median TRE = 2.66 mm) and provided registration runtime of less than 3 s. Similarly in the clinical dataset, JSR achieved median DSC = 0.72 and median TRE = 2.05 mm. Significance. The multi-resolution JSR network resolved deep brain deformations between MR and CBCT images with performance superior to other state-of-the-art methods. The accuracy and runtime support translation of the method to further clinical studies in high-precision neurosurgery.
Influence of ambient temperature on tonic and phasic electrodermal activity components
Authors: Qasim Masood S , Bari Dindar S , Martinsen Ørjan G
Published: May 2022

Objective.Electrodermal activity (EDA) is a reliable indicator for variations in the skin electrical properties attributed to sympathetic nerve system activity. EDA recordings can be influenced by various internal and external factors including environmental ones. Ambient temperature can be considered as one of the possible factors which might influence EDA recordings. Hence, this study aimed to precisely investigate influence of ambient temperature on tonic and phasic EDA components by employing a new EDA measurement technique, which depends on simultaneously recording of several EDA parameters.Approach.Tonic and phasic EDA components during three different ambient temperature levels were recorded from 36 healthy participants. In addition, for evoking electrodermal responses, participants were exposed to cognitive, visual and breathing external stimuli.Main results.Significant effects of temperature on tonic skin conductance (SC), skin susceptance (SS) and skin potential (SP) were obtained, whereas such significant effects were not observed with phasic SC, SS and SP. Tonic EDA parameters were increased as a function of temperature, but changes in phasic component were fluctuating.Significance.This should mean that, keeping recording of tonic EDA component in normal room temperature is highly crucial, but for recording or analysis of phasic component it is not important as they are more robust in this context. This is important in applications of EDA instruments, particularly in wearable devices where environmental temperature typically cannot be controlled.
From 12 to 1 ECG lead: multiple cardiac condition detection mixing a hybrid machine learning approach with a one-versus-rest classification strategy
Authors: Jiménez-Serrano Santiago , Rodrigo Miguel , Calvo Conrado J , Millet José , Castells Francisco
Published: May 2022

Objective. Detecting different cardiac diseases using a single or reduced number of leads is still challenging. This work aims to provide and validate an automated method able to classify ECG recordings. Performance using complete 12-lead systems, reduced lead sets, and single-lead ECGs is evaluated and compared. Approach. Seven different databases with 12-lead ECGs were provided during the PhysioNet/Computing in Cardiology Challenge 2021, where 88 253 annotated samples associated with none, one, or several cardiac conditions among 26 different classes were released for training, whereas 42 896 hidden samples were used for testing. After signal preprocessing, 81 features per ECG-lead were extracted, mainly based on heart rate variability, QRST patterns and spectral domain. Next, a One-versus-Rest classification approach made of independent binary classifiers for each cardiac condition was trained. This strategy allowed each ECG to be classified as belonging to none, one or several classes. For each class, a classification model among two binary supervised classifiers and one hybrid unsupervised-supervised classification system was selected. Finally, we performed a 3-fold cross-validation to assess the system’s performance. Main results. Our classifiers received scores of 0.39, 0.38, 0.39, 0.38, and 0.37 for the 12, 6, 4, 3 and 2-lead versions of the hidden test set with the Challenge evaluation metric (

C
M

). Also, we obtained a mean

G

-score of 0.80, 0.78, 0.79, 0.79, 0.77 and 0.74 for the 12, 6, 4, 3, 2 and 1-lead subsets with the public training set during our 3-fold cross-validation. Significance. We proposed and tested a machine learning approach focused on flexibility for identifying multiple cardiac conditions using one or more ECG leads. Our minimal-lead approach may be beneficial for novel portable or wearable ECG devices used as screening tools, as it can also detect multiple and concurrent cardiac conditions.
On the power and efficiency of Ni2MnGa magnetic shape memory alloy power harvesters
Authors: D’Silva Glen J , Feigenbaum Heidi P , Ciocanel Constantin
Published: May 2022

The martensite variant reorientation in Ni2MnGa magnetic shape memory alloys (MSMAs) causes a change in their bulk magnetization, that can be harvested into useful voltage/power by means of a pick-up coil. The coil may be placed directly surrounding an MSMA element or to the side of the MSMA element wrapped around a magnetic core. This paper reports new power harvesting data generated with a bi-axial magnetic field and a surrounding coil and full strain field data for an MSMA subject to load similar to what is seen during power harvesting, then compares the performance of MSMA-based power harvesters with different designs to determine which give the best output. For this comparison, we provide a framework for evaluating the performance of MSMA-based power harvesters reported in the literature. This framework involves normalizing the results to the design characteristics of the respective harvesters, i.e. number of turns of the pickup coil, cross-sectional area of the pickup coil, frequency of excitation, and sample size, to allow for a direct comparison of power harvesters’ output. Results show that power harvesting with the bi-axial field and a surrounding coil does not generate as much power as previously thought. The strain maps reveal the potential for perpendicular twin boundaries that block each other’s motion limiting variant reorientation and correspondingly the harvester’s power output. The paper concludes that the largest change in magnetic flux density, which is the driver for power harvesting, occurs in the side coil setup with an optimized magnetic circuit and it recommends using this configuration for future MSMA-based power harvester designs for maximum power output.
Significant enhancement of critical current density in H+-intercalated FeSe single crystal
Authors: Meng Yan , Wei Wei , Xing Xiangzhuo , Yi Xiaolei , Zhou Nan , Zhang Yufeng , Liu Wenhui , Sun Yue , Shi Zhixiang
Published: May 2022

Superconducting transition temperature (T
c) and critical current density (J
c) are two key factors that are not only crucial for probing high temperature superconducting mechanism, but also for practical applications. The simple crystal structure of FeSe is very favorable for the fabrication of thin films and wires, but its application is limited by the relatively low T
c and small J
c. Previous studies have found that the T
c of FeSe can be significantly enhanced over 40 K by using protonation method. Here, we present a systematic study of J
c and vortex properties of H+-intercalated FeSe (H
x
-FeSe) single crystals. The value of J
c for H
x
-FeSe single crystal is significantly enhanced, exceeding 1.3 × 106 A cm−2 at 4 K, which is more than two orders of magnitude larger than 1.1 × 104 A cm−2 of pristine FeSe. The vortex pinning mechanism of H
x
-FeSe is found to be surface pinning, which is different from the dominant strong point-like pinning in pristine FeSe. Moreover, the systematic study of the vortex phase transition and the underlying mechanism provides a wealth of information for the vortex phase diagram of H
x
-FeSe single crystal. Our results confirm that the introduction of H+ intercalations into FeSe not only enhance the T
c but also significantly increases the value of J
c, which is favorable for practical applications.
Optimal Prediction of Atmospheric Turbulence by Means of the Weather Research and Forecasting Model
Authors: Rafalimanana Alohotsy , Giordano Christophe , Ziad Aziz , Aristidi Eric
Published: May 2022

The performance of ground-based astronomical observations and free-space optical communication (FSOC) systems suffers from atmospheric turbulence and meteorological conditions. The a priori knowledge of atmospheric conditions several hours before observations allows the programming of astronomical observations (flexible scheduling) to be optimized. In this paper, we present a prediction study based on the Weather Research and Forecasting (WRF) model. It allows the prediction and characterization of a useful set of meteorological parameters relevant to atmospheric physics (e.g., pressure, temperature, relative humidity, wind speed, and direction). Predicted parameters are then injected into an optical turbulence (OT) model to compute the refractive index structure constant C

n

2. We performed sets of simulations for Cerro Pachon Observatory in Chile, using the data from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR). The main goal is to quantify how accurately numerical weather prediction models can reproduce conditions over the complex terrain of the Cerro Pachon area. In order to produce a reliable forecast, meteorological prognostic skills need accurate representations of the physical parameterization options. Three widely used Planetary Boundary Layer (PBL) schemes and two Land Surface Models (LSM) were tested, analyzed, and compared in order to find the optimal WRF configuration. Predictions are compared to in situ measurements coming from balloon-borne radiosoundings. It is determined that the predicted C

n

2 are in good agreement with the radiosoundings measurements with a mean relative error (MRE) under 6.4% at all altitudes when using balloon measurements to deduce some parameters such as the outer scale of turbulence L
0, which is used in the OT model. For a fully operational prediction, the MREs between the predictions and the measurements range from 1.4% to 8% according to the different ways to estimate the L
0 profiles. Seasonal statistics are also presented for different meteorological and turbulence parameters.
Non-destructive assessment of milk quality using pulsed UV photoacoustic, fluorescence and near FTIR spectroscopy
Authors: Khosroshahi Mohammad E , Patel Yesha , Woll-Morison Vaughan
Published: May 2022

The work describes the application of photoacoustic (PA), fluorescence spectroscopy, and Fourier transform near-infrared spectroscopy as non-destructive optical techniques to examine the quality of milk. The amplitude of the acoustic wave was linearly proportional to the absorbed fluence. The acoustic velocity and the fluence threshold for onset of non-linearity were decreased as the fat % increased. Initially, the PA pressure was increased with fluence but it exhibited non-linearity and occurred earlier i.e. faster as the fat % was increased. The peak pressures of 120, 160, and 180 kPa were determined for 1%, 2%, and 3.5% respectively. The corresponding acoustic transient times of 0.5, 0.44, and 0.36 µs were calculated for 1%, 2%, and 3.5% milk respectively. The absorption coefficient of milk samples was determined using the pressure-fluence slope and Grüneisen constant, which increased with fat %. The bandwidths between 350–450 nm and 450–550 nm correspond to tryptophan or valine, and Methionine amino acids respectively, and the peak at ≈315 nm is thought to be due to tyrosine. The fluorescence intensity of the sample day 1 (D1-open) decreased with time more significantly due to variations in the environmental condition. The bands between 4000 and 4500 cm−1 correspond to CH-stretch, and day 4 (D4-closed) showed the highest peak amplitudes compared to the others. Combination of N–H and O–H stretch was mainly observed between 4500 and 5000 cm−1, and the bands at 4581, 4655 cm−1 in fresh sample disappeared in D1-open and D1-closed. New bands of 4717, 4792, and 4829 cm−1 were observed.
Evolution of polarization singularities accompanied by avoided crossing in plasmonic system
Authors: Peng Yi-Xiao , Song Qian-Ju , Hu Peng , Cui Da-Jian , Xiang Hong , Han De-Zhuan
Published: May 2022

The evolution of polarization singularities supported in a one-dimensional periodic plasmonic system is studied. The lateral inversion symmetry of the system, which breaks the in-plane inversion symmetry and up-down mirror symmetry simultaneously, yields abundant polarization states. A complete evolution process with geometry for the polarization states is traced. In the evolution, circularly polarized points (C points) can stem from 3 different processes. In addition to the previously reported processes occurring in an isolated band, a new type of C point appearing in two bands simultaneously due to the avoided band crossing, is observed. Unlike the dielectric system with a similar structure which only supports at-Γ bound states in the continuum (BICs), accidental BICs off the Γ point are realized in this plasmonic system. This work provides a new scheme of polarization manipulation for the plasmonic systems.
A 658-W VCSEL-pumped rod laser module with 52.6% optical efficiency
Authors: Li Xue-Peng , Yang Jing , Zhang Meng-Shuo , Yang Tian-Li , Wang Xiao-Jun , Peng Qin-Jun
Published: May 2022

A high-efficiency and high-power vertical-cavity surface-emitting laser (VCSEL) side-pumped rod Nd:YAG laser with temperature adaptability are demonstrated. The VCSEL side-pumped laser module is designed and optimized. Five VCSEL arrays are symmetrically located around the laser rod and a large size diffused reflection chamber is designed to ensure a uniform pump distribution. Furthermore, the absorbed pump power distribution of the rod is simulated to verify the uniformity of the pump absorption. Finally, a proof-of-principle experiment is performed in short linear cavity laser with single laser module. A continuous-wave output power of 658 W at 1064 nm is obtained, the corresponding optical-to-optical efficiency is 52.6%, and the power variations are ±0.7% over 400 s and ±3.1% over the temperature range from 16 °C to 26 °C. To the best of our knowledge, this is the highest output power and the highest optical-to-optical efficiency ever reported for VCSEL pumped solid-state lasers. By inserting a telescopic module into the cavity and optimizing the TEM00 mode volume, the average beam quality is measured to be M
2 = 1.34 under an output power of 102 W. The experimental results reveal that such a high power rod laser module with temperature stability is appropriate for field applications.
Preclinical safety study of a fully implantable, sub-scalp ring electrode array for long-term EEG recordings
Authors: Benovitski Yuri B , Lai Alan , Saunders Alexia , McGowan Ceara C , Burns Owen , Nayagam David A X , Millard Rodney , Harrison Mark , Rathbone Graeme D , Williams Richard A , May Clive N , Murphy Michael , D’Souza Wendyl J , Cook Mark J , Williams Chris E
Published: May 2022

Objective. Long-term electroencephalogram (EEG) recordings can aid diagnosis and management of various neurological conditions such as epilepsy. In this study we characterize the safety and stability of a clinical grade ring electrode arrays by analyzing EEG recordings, fluoroscopy, and computed tomography (CT) imaging with long-term implantation and histopathological tissue response. Approach. Seven animals were chronically implanted with EEG recording array consisting of four electrode contacts. Recordings were made bilaterally using a bipolar longitudinal montage. The array was connected to a fully implantable micro-processor controlled electronic device with two low-noise differential amplifiers and a transmitter-receiver coil. An external wearable was used to power, communicate with the implant via an inductive coil, and store the data. The sub-scalp electrode arrays were made using medical grade silicone and platinum. The electrode arrays were tunneled in the subgaleal cleavage plane between the periosteum and the overlying dermis. These were implanted for 3–7 months before euthanasia and histopathological assessment. EEG and impedance were recorded throughout the study. Main results. Impedance measurements remained low throughout the study for 11 of 12 channels over the recording period ranged from 3 to 5 months. There was also a steady amplitude of slow-wave EEG and chewing artifact (noise). The post-mortem CT and histopathology showed the electrodes remained in the subgaleal plane in 6 of 7 sheep. There was minimal inflammation with a thin fibrotic capsule that ranged from 4 to 101 μm. There was a variable fibrosis in the subgaleal plane extending from 210 to 3617 μm (S3–S7) due to surgical cleavage. One sheep had an inflammatory reaction due to electrode extrusion. The passive electrode array extraction force was around 1 N. Significance. Results show sub-scalp electrode placement was safe and stable for long term implantation. This is advantageous for diagnosis and management of neurological conditions where long-term, EEG monitoring is required.
Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter
Authors: Zhou Pan , Yao Jiantao , Wei Chunjie , Zhang Shuai , Zhang Hongyu , Qi Shupeng
Published: May 2022

How to further improve the dexterity of continuum robots so that they can quickly change their structural size like flexible biological organs is a key challenge in the field of robotics. To tackle this dexterity challenge, this paper proposes a soft-rigid coupled bioinspired elephant trunk robot with variable diameter, which is enabled by combining a soft motion mechanism with a novel rigid variable-diameter mechanism (double pyramid deployable mechanism). The integration of these two mechanisms has produced three significant beneficial effects: (i) The coexistence of multi-degree-of-freedom motion capability and variable size function greatly improves the dexterity of the elephant trunk robot. (ii) The motion refinement can be improved by structural amplification, making up for the low resolution of soft actuators. (iii) Its stiffness can be increased by enlarging its diameter, while its reachable workspace can be increased by decreasing its diameter. Thus, the elephant trunk robot can optimize its performance when facing different tasks by opening and closing the rigid variable-diameter mechanism. Further, we established a kinematic model of the elephant trunk robot by the structure discretization method and the principle of mechanism equivalence, and experimentally verified its reasonableness. The demonstration experiments show that the elephant trunk robot has good flexibility. This work provides a new variable diameter configuration for continuum robots, and presents a method of how to analyze the kinematics of continuum mechanisms using rigid mechanism theory.
Bioinspired morphing wings: mechanical design and wind tunnel experiments
Authors: Kilian Lukas , Shahid Farzeen , Zhao Jing-Shan , Nayeri Christian Navid
Published: May 2022

Bioinspired morphing wings are part of a novel research direction offering greatly increased adaptability for use in unmanned aerial vehicles. Recent models published in the literature often rely on simplifications of the bird wing apparatus and fail to preserve many of the macroscopic morphological features. Therefore, a more holistic design approach could uncover further benefits of truly bioinspired bird wing models. With this issue in mind, a prototype inspired by crow wings (Corvus genus) is developed, which is capable of planform wing morphing. The prototype imitates the feather structure of real birds and replicates the folding motion with a carbon fiber reinforced polymer skeleton with one controllable degree of freedom. The mechanism supplies a smooth airfoil lifting surface through a continuous morphing motion between a fully extended and a folded state. When extended, it has an elliptic planform and emarginated slots between primary remiges. In the folded state, the wingspan is reduced by 50% with a 40% reduction in surface area and the aspect ratio decreases from 2.9 to 1.2. Experimental data from a subsonic wind tunnel investigation is presented for flow velocities ranging from 5 to 20 m s−1, corresponding to Reynolds numbers between 0.7 × 105–2.8 × 105. The wing is analyzed in the three static states (folded, intermediate, and extended) through aerodynamic coefficients and flow visualizations along the surface. The bioinspired design enables the wing to capture several phenomena found on real bird wings. Through its morphing capabilities and intrinsic softness, the wing can sustain large angles of attack with greatly delayed stall and maintain optimal performance at different velocities.
Rapid fabrication of tendon-like collagen gel via simultaneous fibre alignment and intermolecular cross-linking under mechanical loading
Authors: Maeda Eijiro , Kawamura Ryota , Suzuki Takashi , Matsumoto Takeo
Published: May 2022

Artificial tissue replacement is a promising strategy for better healing outcomes for tendon and ligament injuries, due to the very limited self-regeneration capacity of these tissues in mammals, including humans. Because clinically available synthetic and biological scaffolds for tendon repair have performed more poorly than autografts, both biological and mechanical compatibility need to be improved. Here we propose a rapid fabrication method for tendon-like structure from collagen hydrogel, simultaneously achieving collagen fibre alignment and intermolecular cross-linking. Collagen gel, 24 h after polymerization, was subjected to mechanical loading in the presence of the chemical cross-linker, genipin, for 24 or 48 h. Mechanical loading during gel incubation oriented collagen fibres in the loading direction and made chemical cross-linking highly effective in a loading magnitude-dependent manner. Gel incubated with 4 g loading in the presence of genipin for 48 h possessed tensile strength of 4 MPa and tangent modulus of 60 MPa, respectively, which could fulfill the minimum biomechanical requirement for artificial tendon. Although mechanical properties of gels fabricated using the present method can be improved by using a larger amount of collagen in the starting material and through optimisation of mechanical loading and cross-linking, the method is a simple and effective for producing highly aligned collagen fibrils with excellent mechanical properties.
Temporal variations of the association between summer season heat exposure and hospitalizations for renal diseases in Queensland, Australia, 1995–2016
Authors: Lu Peng , Miao Jiaming , Feng Shurong , Green Donna , Lim Youn-Hee , Gao Xiuwei , Li Shanshan , Guo Yuming
Published: May 2022

To examine the temporal trends of the association between heat exposure and hospitalizations for renal disease in Queensland, Australia, between the summer season of 1 December 1995 and 31 December 2016. A total of 238 427 de-identified hospitalization records for renal disease were collected from Queensland Health. Meteorological data was obtained from the Scientific Information for Land Owners. Summer season means four consecutive months with higher daily mean temperatures. We conducted a time-stratified case-crossover study using conditional quasi-Poisson regression model and applied a time-varying distributed lag non-linear model were used to evaluate the temporal trends of the associations between 1 °C increase in daily mean temperatures (over 0–10 lags) and hospitalizations for renal diseases. We also conducted stratified analyses by sex, age, climate zone, socioeconomic status, and cause-specific renal diseases. Overall, the associations between high temperature and hospitalizations for renal diseases showed a decreasing trend during the summer seasons from 1995 to 2016. However, the heat-related effects in males increased from 3.0% (95% CI: 2.2%, 3.9%) in 1995 to 4.8% (95% CI: 3.9%, 5.6%) in 2016. In the elderly cohort (both sexes), there was a similar increase over time 2.0% (95% CI: 1.0%, 3.0%) in 1995 to 6.3% (95% CI: 5.4%, 7.3%) in 2016. People living in hotter climate zones and those living in relatively socioeconomically disadvantaged areas also showed an increasing trend. In the cause-specific disease analysis, the increasing trend was found in renal failure, with heat-related effects increased from 3.45% (95% CI: 2.31%, 4.60%) in 1995 to 8.19% (95% CI: 7.03%, 9.36%) in 2016. Although the association between temperature and hospitalizations for renal diseases showed a decreasing trend in Queensland’s hot season between 1995 and 2016, the susceptibility to high temperatures is increasing in males, the elderly of both sexes, those living in hotter climate areas, and socioeconomically disadvantaged areas. This increasing trend of susceptibility is a great concern and indicates a strong need for targeted public health promotion campaigns.
Electric double layers with modulated surface charge density: exact 2D results
Authors: Šamaj Ladislav
Published: May 2022

Electric double layers (EDL) with counterions only, say electrons with the elementary charge −e, in thermal equilibrium at the inverse temperature β are considered. In particular, we study the effect of the surface charge modulation on the particle number density profile and the pressure. The mobile particles are constrained to the surface of a 2D cylinder and immersed in vacuum (no dielectric image charges). An EDL corresponds to the end-circle of the cylinder which carries a (fixed) position-dependent line charge density. The geometries of one single EDL and two EDLs at distance d are considered; the particle density profile is studied for both geometries, the effective interaction of two EDLs is given by the particle pressure on either of the line walls. For any coupling constant Γ ≡ βe
2 = 2 × integer, there exists a mapping of the 2D one-component Coulomb system onto the 1D interacting anticommuting-field theory defined on a chain of sites. Using specific transformation symmetries of anticommuting variables, the contact value theorem is generalized to the EDL with modulated line charge density. For the free-fermion coupling Γ = 2 it is shown that, under certain conditions, the matrix of interaction strengths between anticommuting variables diagonalizes itself which permits one to obtain exact formulas for the particle density profile as well as the pressure. The obtained results confirm the previous indications of weak-coupling and Monte Carlo observations that the surface charge inhomogeneity implies an enhancement of the counterion density at the contact with the charged line and a diminution of the pressure between two parallel lines in comparison with the uniformly charged ones (with the same mean charge densities).
Assessment of the main rheological parameters of rocks during field development
Authors: Khabibullin M Ya
Published: May 2022

The total rock pressure on a formation wing is greater than the lateral pressure, and on the fold, on the contrary, the lateral rock pressure is greater than the total pressure. As a result, the formation material flows from wing zones to the fold, as a result of which the formation thickness on the fold increases, as noted by the studies of Soviet scientists. The study of the mechanism of hydraulic fracturing during water injection revealed large fracturing pressures in wells located in reduced parts of the structure (fold wings), and smaller pressures – in elevated parts (fold). The study showed that if the rock of the well bore zone is destabilized during field development for well operation, fresh water causes hydration and swelling or dispersion of clays, which act as the rock cementing material. This can both lead to a decrease in permeability and to the destruction of the well bore zone. This effect during well development may be prevented by using mineralized reservoir water or fresh water with hydration inhibitor additives such as NaCl (5-10%), CaCl2 (1-3%), KC1 (1-3%). Another complication in well completion is the colmatation of the well bore zone. In order to ensure the stability of the fixed part of the formation behind tubing in the bottomhole zone, there is a need to ensure the static equilibrium in the porous medium. Rocks with low rheological properties (low relaxation rate) provide longer resistance of the well bore zone to destruction.
Calculation and Forecast of Resource Extraction during Exploration
Authors: Mukhametshin V Sh
Published: May 2022

Vast experience accumulated in the development of various groups of deposits in the carbonate reservoirs of the Volga-Ural oil and gas province, gave a set of geological and statistical relationships enabling to calculate and forecast resource extraction, provided that a representative volume of geological and field data is not available at the stage of geological exploration. The findings show that developing deposits in carbonate reservoirs requires a differentiated approach due to some specific features of oil recovery in these deposits.
The dependence of the efficiency of hydraulic fracturing on the geological factors of the Tourne-Famene deposit at the Gagarinsky oilfield
Authors: Galkin V I , Chalova P O
Published: May 2022

In this article, a factor analysis of well flow rate increase after hydraulic fracturing depending on facies conditions is carried out using the example of the Turne-Famenskoye reservoir of the Gagarinskoye field as an example. By constructing the equations of multiple regression, the influence of geological factors on the productivity coefficient and, consequently, on the additional oil production was determined. Based on the results of factor analysis and construction of statistical models, high significance of bottom hole and formation pressure values and their change depending on facial environment has been established. It is recommended to select candidate wells for hydraulic fracturing operations taking into account their facial affiliation, specific features of wells where hydraulic fracturing operations were carried out quite effectively, taking into account residual reserves density, water cut of well production, proximity to oil-bearing contour and to injection wells.
The mathematical layer structure of the digital twin of hazardous production facilities at a gas transmission enterprise
Authors: Kirilov A E , Chernyi K A
Published: May 2022

The article presents the structure of the mathematical layer for digital twins (DT) of hazardous production facilities (HPF) operated by gas transportation enterprises. Mathematical models of technical device destructions, models to control parameters of technological processes are presented, the types of affecting factors which can influence the personnel of HPF are described, as well as a safety assessment model for the evacuation of personnel in the event of an accident or a fire. The presented structure of DT and models make it possible to adequately describe the features of HPF and optimise operational safety. The areas of application of digital twins in the production activities of a gas pipeline enterprise have been determined. To determine the most possible scenarios of accidents at HPF the presented models have been tested and implemented in the operational activities of JSC “Gazprom transgaz Tchaikovsky”.
Evaluation of hydrocarbon resources of the Devonian terrigenous rock basin of Perm Region
Authors: Kozlova I A , Borisova D D
Published: May 2022

The geological structure of the Devonian terrigenous complex within the Bashkirian arch located in the well-explored southern part of Perm Krai has been considered in the paper. Due to the limited extent and complex structure of the bulk of reservoir rock in the prospective horizons, these deposits are explored unevenly, usually alongside with the overlying oil and gas bearing complexes. On the basis of the performed analysis of systematic data, the authors justify quantitative parameters for evaluation of non-localized resources after the method of comparative geological analogies in the Devonian terrigenous deposits. The estimated quantity of hydrocarbon resources in the territory under study unequivocally defines it as prospective for exploration and discovery of reserves in the Devonian oil and gas bearing complex. Therefore, the authors have identified areas for priority prospect evaluation survey taking into account the extent of the most promising facies zones of deltaic channels and beach bars.
Impact of hydraulic fracturing on development indicators at BS10, BS11, US11 zones of Yuzhno-Yagunskoye field
Authors: Gabdrakhmanov N Kh , Almukhametova E M , Karimova A A , Stepanova R R
Published: May 2022

The study considers three production zones of Yuzhno-Yagunskoye field. The study analyzes one method of oil intensification from the formation, namely Hydraulic Fracture Treatment (HFT), and provides the results of its influence on development indicators within three zones of Yuzhno-Yagunskoye field. A series of hydraulic fracturing operations was carried out in the period from 1995 to 2017. The methods for analyzing the bottomhole zone of the formation were used to process field data. However, it should be noted that in comparison with previous periods of hydraulic fracturing technology, the effect is reduced, which implies further modification of the used hydraulic fracturing technology. The purpose of this study is to evaluate the process efficiency of hydraulic fracturing at Yuzhno-Yagunskoye field. The above results were used during hydraulic fracturing at Yuzhno-Yagunskoye field.
Use of geotechnical monitoring data in the design of the Serginsky field development
Authors: Shakurova Alsu F , Shakurova Aygul F
Published: May 2022

The paper deals with the use of geotechnical monitoring data to substantiate commissioning of production facilities in the Serginsky field. At the first stage, the geological and physical features of the reservoirs of the Serginsky field were considered; at the second stage, the results of substantiation were adjusted with regard to technological and economic factors. In addition, the experience of deposit exploitation gained during the period of pilot industrial development of the field was considered to substantiate commissioning of production facilities. The main part of the oil reserves of the Serginsky field (85%) is accumulated in two reservoirs J2-3 and J10. Geological oil reserves of J1 and J4 reservoirs account for about 15.2% of the total oil reserves of the field.
The structure of the oil-bearing strata and possibility of extracting oil from them
Authors: Akhmetianova L B , Bagmanov R N , Raymanov M M , Kobishcha D I , Sagitova Z N
Published: May 2022

It is important to study the structure of oil-bearing strata is. In many ways, the structure of the Earth’s layers affects the possibility of intensifying oil production. This is one of the urgent problems of the oil industry. Obviously, at various stages of oil field development, methods of intensifying oil production, depending on the structure of oil-bearing rocks and geological and physical characteristics have their own features, which are manifested when they are used in the field conditions. Determination of the oil recovery factor (ORF) causes great difficulty in the operational assessment of oil reserves. At the stage of initial assessment, this indicator is taken either by analogy, or approximately. In order to make this parameter more valid, the main factors influencing its formation were studied. The formula for calculating oil recovery factor takes into account three main coefficients: grids, displacement and waterflooding.
Development of an experimental set-up for studying the effect of elastic oscillations on fluid flow through rocks
Authors: Riabokon E P , Kazantsev A L , Gladkikh E A , Turbakov M S
Published: May 2022

The article presents the results of experimental studies of the influence of elastic oscillations on the structure of paraffin oil of a Perm region field. Oil samples are treated by elastic oscillations at a frequency of 22 kHz. As a result of cavitation and an increase in oil temperature, a decrease in the concentration and a decrease in the size of high-molecular paraffin compounds in oil is observed. With an increase in the time of ultrasonic treatment, the intensity of dissolution of paraffins in oil increases. A model of an experimental setup is proposed to study the effect of elastic oscillations on the permeability of a rock during the flow of paraffin oil. The impact of permeability deterioration around the production well on its flow rate is assessed.
Ways to improve the development efficiency in the complex-structured carbonate deposits of the Tournaisian stage using hydraulic fracturing
Authors: Grishchenko V A , Mukhametshin V V , Kuleshova L S
Published: May 2022

Depletion of the main oil reserves within the Volga-Ural oil and gas province causes a constant shift in production volumes towards complex low-productive carbonate deposits. Clarification of the geological structure, which has a prevailing effect on the final result, is carried out in order to ensure an efficient process of developing reserves. The analysis of the influence of clay dam thickness between oil and water-saturated formations was done for various injection sites on the efficiency of hydraulic fracturing and treatment of the bottom-hole zone in production wells. The study showed that the critical value of the dam thickness is equal to three meters; the waterflooding efficiency is significantly reduced below this value.
Substantiation of geological exploration and modeling of oil deposits for multistage fracturing in a horizontal well
Authors: Voronova E V , Petrova L V , Gutorov A Yu
Published: May 2022

To date, an increase in the oil recovery factor by commissioning horizontal wells is of relevance for oil fields at the late exploitation stage. In most cases, horizontal wells are developed using multistage fracturing; therefore, it is crucial to determine the criteria affecting its successful implementation. The study results are of use for a more reasonable approach to the choice of the location of horizontal wellbores and increase in the efficiency of geological exploration and multistage hydraulic fracturing.