bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a mathematical model of the interaction of the knife actuator of geokhod with the semiconvex shape of the cutting edge of the knife with the mine faces rock
Authors: Aksenov Vladimir , Sadovets Vladimir , Preis Elena , Pashkov Dmitry
Published: September 2021

The paper discusses the relevance of the research. To set the goal and objectives of the research, the developed schematic solution of the knife actuator of Geokhod with a semiconvex shape of the cutting edge of the knife is presented. There is no mathematical model of the interaction to determine the force parameters of the interaction of the knife actuator of Geokhod with the semiconvex shape of the cutting edge of the knife with the mine face rock. As a result, a mathematical model has been developed for the interaction of the knife actuator of Geokhod with the semiconvex shape of the cutting edge of the knife with the mine face rock. The obtained systems of analytical expressions make it possible to determine the projections of the components of the cutting forces on the axis of Geokhod and the plane perpendicular to the axis of Geokhod rotation, as well as the moment of the forces of resistance to cutting by the knife actuator of Geokhod with a semiconvex shape of the cutting edge of the knife.
Emission of gases from coal at low-temperature oxidation depending on the oxygen sorption rate
Authors: Portola Vyacheslav , Bobrovnikova Alyona , Zeng Qiang
Published: September 2021

Coal oxidation by air oxygen can cause a process of spontaneous combustion with intense emission of carbon oxide and danger to initiate explosion of combustible gases. To detect the process of coal spontaneous combustion in mines, they use a gas analysis method providing control of concentrations of carbon oxide, hydrogen and hydrocarbons in the atmosphere. The conducted researches showed that at low-temperature oxidation of coal the intense emission of these gases without temperature increase is possible. Concentration of carbon oxide significantly increases with the growth of coal oxygen sorption rate. Ethylene and carbon dioxide show similar regularities. Acetylene is not found as a result of low-temperature oxidation of coal, and emission of hydrogen, methane, ethane, propane and propylene does not depend on the coal oxygen sorption rate.
Experimental development process of similar material of water resisting layer in physical model test
Authors: Liu Qi , Chen Shaojie , Wang Shuai , Chai Jing , Zhang Dingding , Yao Kailiang
Published: September 2021

The stability evaluation of water resisting layer in the process of coal mining is the key to study the law of water and soil loss and prevent the loss of water resources. The development and proportioning of similar materials are the basis to study the stability of water resisting layer by physical simulation. A new type of similar material considering water characteristics was developed through orthogonal experiments. The similar material was composed of river sand, bentonite, silicone oil, vaseline, and water. Determine the best test development process. First of all, the proportion test scheme is designed based on the orthogonal test. Then, the influence of cement concentration, mass ratio of silicone oil to vaseline and other components on the density, uniaxial compressive strength, elastic model and Poisson’s ratio of similar materials was analyzed by range analysis. Finally, the multiple linear regression equation between the parameters and the composition of similar materials for water resisting layer is obtained, and the optimal composition ratio is further determined according to the relationship between the test influencing factors and the mechanical properties of similar materials. The results show that the selected raw materials and their proportioning method are feasible. The content of river sand plays a major role in controlling the density and Poisson’s ratio of similar materials. The mass ratio of aggregate to binder is the main factor affecting the uniaxial compressive strength and elastic modulus of similar materials, while the cementing concentration has the second largest influence on the density, uniaxial compressive strength, elastic modulus and Poisson’s ratio of similar materials. Determining the cementing concentration that matches the design of similar material model tests is critical to improving test accuracy and provides a reference for the preparation of similar materials for water resisting layer under different requirements during the development of similar materials.
Landslide hazard zones determination on open pit mine edge by circular seismic sounding method
Authors: Karablin Mikhail , Sirota Dmitry , Prostov Sergey , Abdurasulov Olmos
Published: September 2021

Herein there is an algorithm and method of processing the experimental data obtained by a circular seismic sounding method that makes it possible to increase accuracy in determining an anisotropy coefficient of the ground mechanical properties. The coefficient value is mutually related to the deformation processes at the initial stages of landslide formation. There are results of data processing of the field seismic studies of the adjacent ground at the Angrenskiy coal mine that allow establishing boundaries for the potentially landslide-prone zones, as well as a numerical criterion to predict rock stability under the given conditions.
Motion model and key parameters of overburden strata in longwall filling face
Authors: Yin Zengde , Liu Jinxiao , Zhang Feng , Liu Yongle , Li Wenxin
Published: September 2021

When the paste material is filled into the longwall working face of the coal mine, it firstly controls the movement of the overburden strata, thereby limiting the movement of the far field rock layer and reducing the subsidence. With this regard, the paste filling technology of the long-wall mining can address the limitation of “three down, one up” (mining under water body, building and rail, and on karst water body) technology in coal mining, thus improving the extraction rate of coal resource. To control the movement of the overburden strata near the working face, the prerequisite is to clarify the relationship among the parameters, including coal mining thickness, filling body thickness, filling step, filling body strength, etc. On this basis, this paper established an overall mechanical model of the filling body and surrounding rock, and determined the key technical parameters of the overburden movement, i.e., the filling rate, the strength of the filling body, and the filling step. Then, the influence of these parameters on the overburden movement and abutment pressure was analyzed through the numerical simulation method. The results show that at a higher filling rate, the overburden motion can be better controlled; the filling step only had a significant effect on the roof subsidence within the relevant step; as the early strength of the filling body was higher, the overburden subsidence was smaller and the abutment pressure in front of the face was better controlled. The research of overburden motion model and its key parameters have a good guiding significance for paste filling in the longwall face of coal mines.
Numerical and in-situ investigation on the ground behavior of the end roof in fully mechanized caving face
Authors: Zang Chuanwei , Chen Miao , Chen Yang , Zhuang Xuean , Zhai Chenming , Zhu Hongmo
Published: September 2021

Fully mechanized top coal caving is a major high-yield and high-efficiency coal mining method for thick seam mining. At present, it is affected by the further popularization and application of fully mechanized caving mining because the recovery rate is limited. The research on the technology of fully mechanized top coal caving and transitional coal mining is crucial. This paper aims at the top coal recovery with the top coal of the fully mechanized caving face and the transitional frame at both ends of the working face. With the top roof structure model of the fully mechanized caving face, the numerical simulation and field measurement is used to compare the end coal caving. With caving coal or not, the destruction and migration rules of the top coal in the fully mechanized caving face are obtained. The study found that at the end of the transport trough, the maximum concentration factor of the support pressure in the coal is 2.35, and the maximum vertical displacement is 9.2cm. And at the end of the return air trough, the support pressure concentration factor is 3.53, and the maximum vertical displacement of the roof is 102cm. The above research reveals the law of the occurrence of the pressure and the movement of the top coal when caving the coal at the end, while ensuring the safe production and efficient mining of the coal mine.
Open pit mine wastewater filtration in the overburden rock debris: case study
Authors: Makridin Eugene , Markov Sergey , Murko Elena , Ondrejmiskova Ivana
Published: September 2021

Discharge of untreated quarry water into natural water reservoirs is unacceptable for environmental reasons. This circumstance is especially relevant for coal mining regions with a high density of mining enterprises. Treatment of quarry waste water at mining enterprises is a necessary process, provided for in the design documentation. It is due to the significant pollution of quarry water by suspended solids, dissolved salts and organic substances. In addition to expensive sorbents (e.g. zeolite), overburden rocks, confined to the mined area of coal deposit, are used for construction of filtering dams. They are used to construct treatment facilities designed for the entire lifetime of the mining enterprise. Thus, their permeability and purification capacity should be maintained for decades. The movement of filtered water in such massifs is subject to the known laws of filtration. Filtering dams should provide both a free movement of water and the required level of its purification. This is achieved by selecting the appropriate geometry of filter dams (their sizes, base slopes) and the choice of overburden capable of providing the required level of purification in a long and qualitative term. The article presents the results of studies of the geometry of the filtering massif and the methodology of selection of overburden used for the construction of filtering dams.
Quantitative safety evaluation of drilling engineering by combining analytic hierarchy process with alternating condition expectation
Authors: Kunkun Fan , Fangxiang Wang , Chunguang Wang , Shaojie Chen , Hai Lin , Jia He , ZhongweI Chen
Published: September 2021

Drilling engineering is important for development of underground resources. There are many potential risks in the process of drilling engineering. If the drilling safety is not effectively managed, it will lead to great loss. In order to predicate and prevent safety accidents, a safety evaluation index system is established and an AHP-ACE method is proposed. 23 groups of original drilling data are collected from a block of Xinjiang oil field, and the safety levels are quantitatively analyzed by characteristic values. First, the AHP method is applied to relate direct observation variables to potential variables by calculating weight and determining membership function of each index. Second, three potential variables are chosen as the input of the ACE model and a training set containing 17 groups of data is used to establish the mathematical relationship between the potential variables and drilling safety value. Finally, the validity of the proposed model is examined by matching it to the other 6 groups of data. This study provides a new and effective way to quantitatively evaluate the safety of drilling engineering.
Technological schemes of coal extraction in closed mines with the use of backhoes
Authors: Makarov Vladimir , Kolesnikov Valery , Szurgacz Dawid
Published: September 2021

At the present time on the fields of operating and closed-down mines there are sections of open-pit operations. However, the adopted technology does not meet environmental requirements, there are no scientific recommendations on the technology of open-pit mining in hazardous areas of mine fields, there is no substantiation of the boundary contours of open-pit mining. A characteristic feature of depleted mine fields is the disturbed rock mass and the lack of concentrated coal reserves within their boundaries. In fact, coal reserves are represented in the form of fragmentary volumes of safety pillars and substandard reserves in places of geological disturbances. Limitation of mine fields in terms of various infrastructure objects imposes special requirements for mining operations. In these conditions it is not possible to apply the classic mining systems and technologies. This predetermines the necessity to develop new technological solutions. Therefore, scientific research on justification of technology for extraction of remaining reserves of coal after underground development of inclined and steep-sloping coal deposits with simultaneous reclamation of disturbed lands is actual.
RETRACTED: Sustainable integrated and pricing decisions for two-echelon supplier–retailer supply chain of growing items
Authors: Choudhury Mukunda , Mahata Gour Chandra
Published: September 2021

The paper "Sustainable integrated and pricing decisions for two-echelon supplier–retailer supply chain of growing items" (authors: Mukunda Choudhury and Gour Chandra Mahata), v.55(5), pp.3171-3195, September-October 2021, RAIRO Operations Research, after a very careful investigation process, which proved the existence of plagiarism, was retracted by the editorial board of this journal.
Effects of Breaking Up Prolonged Sitting on Cardiovascular Parameters: A systematic Review
Authors: da Silva Gustavo Oliveira , Santini Luiza Batista , Farah Breno Quintella , Germano-Soares Antonio Henrique , Correia Mariliade Almeida , Ritti-Dias Raphael Mendes
Published: September 2021

The aim of this systematic review was to analyze the acute and chronic effects of sitting breaks on cardiovascular parameters. PubMed and Web of Science databases were searched by two independent researchers for relevant studies published until February 2020. Acute or chronic studies reporting the effects of sitting breaks or reduction in sitting time on cardiovascular parameters were examined. The eligibility criteria followed PICOS: Population - Humans ≥ 18 years old; Interventions – Sitting break strategies; Comparisons – Uninterrupted sitting; Outcomes – Cardiovascular parameters (blood pressure, heart rate, ambulatory blood pressure, vascular function, pulse-wave velocity, cerebral blood flow and biomarkers); Study design – Randomized controlled trials, non-randomized non-controlled trials and randomized crossover trials. Forty-five studies were included, where 35 investigated the acute and 10 the chronic effects of sitting breaks or reductions in sitting time. Walking was the main acute study strategy, used in different volumes (1 min 30 s to 30 min), intensities (light to vigorous) and frequencies (every 20 min to every 2 h). Acute studies found improvements on cardiovascular parameters, especially blood pressure, flow-mediated dilation, and biomarkers, whereas chronic studies found improvements mostly on blood pressure. Breaking up or reducing sitting time improves cardiovascular parameters, especially with walking.
Sudden Unexpected Death of Two Infants in Baby Carriers
Authors: Storz Dennis , Dame Christof , Wendt Anke , Gratopp Alexander , Bührer Christoph
Published: September 2021

Sudden unexpected death in infancy (SUDI), previously termed sudden infant death
syndrome (SIDS), is the second leading cause of death in infants beyond the neonatal
period in Germany, and a major cause of infant mortality in economically well
developed countries (OECD Health Statistics, 2019). The risk of SUDI peaks at the
age of 2–4 months and then decreases continuously till the end of the first
year. A complex multifactorial cause, rather than a single characteristic factor,
may cause SUDI within a critical period of infant development (Guntheroth WG et al.,
Pediatrics 2002; 110: e64–e64). Risk factors include prematurity, male
gender, bottle-feeding, prone sleeping position, overheating, as well as exposure to
smoke amongst others (Carpenter RG et al., Lancet 2004; 363: 185–191). Thus,
health professionals consistently advise and educate parents about avoidable risk
factors of SUDI at routine well-baby examinations. Since the advent of SUDI
prevention strategies in the 1980s, the incidence has decreased 10fold, from
1,55/1.000 live births in 1991 to 0,15/1000 in 2015. This number
seems to have reached a steady state (Statistisches Bundesamt Germany, 2015).
Kopfschmerzen bei Kindern – aktuelle Empfehlungen und
Krankengeschichten
Authors: Lucae Christian
Published: September 2021

Kopfschmerzen sind im Kindes-und Jugendalter ein häufiger
Vorstellungsgrund in der pädiatrischen Praxis. Dazu werden aktuelle
Empfehlungen zu Diagnostik und konventioneller Therapie erläutert.
Anschließend werden anhand von 4 exemplarisch ausgewählten
Krankengeschichten homöopathische Therapiemöglichkeiten
dargestellt, die sich problemlos in ein integratives Konzept eingliedern
lassen.
Das Phytotherapeutikum Johanniskraut: Die Möglichkeit seiner
Anwendung in der Onkologie
Authors: Pfuhlmann Katrin , Klose Petra , Langhorst Jost
Published: September 2021

Bestimmte Extrakte des Johanniskrautes sind in Deutschland als Arzneimittel
zugelassen und können auf Patientenwunsch zur Therapie der leichten bis
mittelschweren Depression sowie zur kurzzeitigen symptomatischen Therapie bei
leichter depressiver Verstimmung angewandt werden. Eine Überlegenheit
oder Gleichwertigkeit von Johanniskraut gegenüber Placebo in klinischen
Studien, geringe Nebenwirkungen sowie eine gute Patientenakzeptanz
natürlicher Arzneimittel sind Gründe, die für eine
Therapie mit Johanniskraut sprechen. Klinische Studien, welche explizit die
Wirksamkeit von Johanniskraut auf die Depressivität onkologischer
PatientInnen untersuchen, liegen derzeit nicht vor. Die S3 Leitlinie
„Komplementärmedizin in der Behandlung von onkologischen
PatientInnen“ beschreibt, in Anlehnung an die Nationale
Versorgungsleitlinie „Unipolare Depression“, eine
mögliche Anwendung im Rahmen auftretender Depressionen im onkologischen
Kontext. Im Rahmen der Therapie des Mammakarzinoms kann Johanniskraut gegen
Hitzewallungen eingesetzt werden. Erste experimentelle Ex-vivo-Versuche zeigen
eine mögliche antikanzerogene Wirkung des Johanniskrautes. Diese
Ergebnisse gilt es in großangelegten, qualitativ hochwertigen,
klinischen Studien zu prüfen.
Synthesizing Highly Fluorinated Oligophenyls via Negishi Coupling of Fluoroarylzinc Pivalates
Authors: Stoesser Julian , Huber Stefan M. , Engelage Elric
Published: September 2021

Previously established general synthetic methods for the synthesis of highly fluorinated biphenyls using Suzuki–Miyaura protocols require the use of organoboron compounds, which are not very stable under reactions conditions and thus need to be used in large excess. Herein, we report an improved general strategy for the synthesis of highly fluorinated biphenyls, terphenyls, and phenyl-substituted terphenyls using organozinc pivalates. The influence of several parameters was investigated: (1) in a series of monodentate phosphine ligands, X-Phos showed the best performance; (2) a higher yield was obtained for substrates bearing less steric hindrance or lower amount of fluorine substitution; (3) as iodinated substrates decomposed during the reaction, brominated electrophiles were found to be superior. The presented protocol is scalable, versatile, and works with commonly used and commercially available phosphine ligands (X-Phos) and palladium sources (Pd2dba3). Also, it does not require excess nucleophile for terphenyl synthesis and only a slight excess is needed for the preparation of phenyl substituted terphenyls.
Synthesis and Characterization of Hybrid Dimeric Steroid Spiroketals
Authors: Iglesias-Arteaga Martín A. , Mayorquín-Torres Martha C. , Maldonado-Domínguez Mauricio , Flores-Álamo Marcos
Published: September 2021

The synthesis of six dimeric spiroketals bearing an estradiol half fused to the 5α- or 5β-epimers of androstane, cholestane, and spirostane nuclei is described. The synthetic procedure comprises the Sonogashira­ coupling of different steroid alkynes with 2-iodoestradiol 17-monoacetate, followed by Pd-catalyzed spiroketalization. The structural characterization of the obtained hybrid dimers was performed using a combination of 1D and 2D NMR techniques, and was assisted by DFT calculations. Single crystal X-ray diffraction of one of the obtained compounds confirmed the proposed structures.
Long-Term Outcome of Children with Short Bowel Syndrome Treated with a Modification of the STEP Technique Avoiding Mesenteric Defect
Authors: Bueno Javier , García-Martínez Laura , Redecillas Susana , Segarra Oscar , López Manuel
Published: September 2021

Background The Serial Transverse Enteroplasty Procedure (STEP) Registry has reported a 47% success to achieve enteral autonomy in pediatric short bowel syndrome (SBS). We have performed the STEP with a technical modification (MSTEP) consisting in stapler application without mesenteric defects that can also be applied to the duodenum. Our experience with this technique is described.

Materials and Methods In this study, 16 children with SBS underwent MSTEP (2005–2019). Indications were nutritional autonomy achievement (n = 11, with duodenal lengthening in 5/11) and bacterial overgrowth treatment (n = 5).

Results With a median follow-up of 5.8 years (0.7–13.7 years), 5 of 11 (45%) patients achieved enteral autonomy, 4 of them with duodenal lengthening. Four of four who preserved > 50% colon, while only one of seven with < 50% of colon achieved enteral autonomy (p < 0.05). After redo procedures, three of four attained enteral autonomy. Thus, 8 of 11 (73%) progressed to enteral autonomy, including all with duodenal lengthening. One child, already parenteral nutrition free, died due to central line sepsis. All the patients from the bacterial translocation group improved their metabolic/nutritional status, but one required subsequent enterectomy of the lengthened intestine due to multiple ulcers in the staple lines.

Conclusion The effectiveness of MSTEP to achieve enteral autonomy seems similar to the classical STEP. It can be applied to the duodenum. The retained colon length may influence the post-STEP enteral autonomy achievement.
Use of 3D Printed Models to Determine Accurate Bone Cuts during a Periacetabular Osteotomy for Developmental Hip Dysplasia
Authors: Driesman Adam , Buchalter Daniel , Kirby David J. , Wake Nicole , Castaneda Pablo
Published: September 2021

The periacetabular osteotomy (PAO) is a powerful tool to delay the progression of hip arthritis by reorienting the acetabulum. This study aimed to use three-dimensional (3D)-printed models of the pelvis, reconstructed from the computed tomography (CT) scans of patients, to model how the level of dysplasia and its location ilium osteotomy affect radiographic outcomes following PAO. This pilot study aims to determine if preoperative 3D printing/planning can assist in predicting radiographic outcomes. We performed a retrospective review of five patients with differing levels of hip dysplasia for whom we had obtained CT scans before PAO surgery. For each patient, we printed two pelvis models that would undergo standardized cuts of the PAO procedure, with variations only in the distance of the ilium start point (one-third of the distance between the anterior superior iliac spine and anterior inferior iliac spine [AIIS] vs. two-thirds of the distance). We then mobilized the acetabular fragment into eight reproducible positions in space by moving the ilium cut a combination of 0, 1, or 2 cm anterior/lateral. Each position of the newly realigned acetabula was examined under fluoroscopy to obtain a standardized anteroposterior view, and to obtain standardized radiographic measurements in the form of lateral center edge angle (CEA), acetabular depth, Tonnis angle, and acetabular inclination. We performed 80 simulations of the PAO with varying degrees of acetabular mobilization. On average, in the models where the supra-acetabular cut was closer to the AIIS, we found more significant degrees of radiographic correction, regarding Tonnis angles (12.91 vs. 7.95, p = 0.0175), acetabular inclination (20.25 vs. 9.875, p = 0.027), and lateral CEA (11.75 vs. 2.5, p = 0.061). Patients who had greater dysplasia also had more significant degrees of radiographic Tonnis angle correction with the same mobilization movements of the acetabula (p = 0.005). When utilizing 3D printing to model PAO in dysplasia pelvises, we found that both a higher level of preoperative dysplasia and starting the supra-acetabular osteotomy closer to the AIIS were associated with more powerful corrections following smaller manipulations.
Complications and Unsuccessful Same-Day Discharge Following Outpatient Total Hip Arthroplasty (THA) in the Medicare Population: Incidence, Risk Factors, and Clinical Impact
Authors: Gordon Adam M. , Malik Azeem Tariq
Published: September 2021

In 2020, total hip arthroplasty (THA) was removed from the inpatient-only list by the Centers for Medicare and Medicaid Services. The objective was to analyze outpatient THA in the Medicare population to understand incidence of failed same-day discharge (SDD) and risk factors for complications and extended length of stay (LOS). The 2015–2019 American College of Surgeons—National Surgical Quality Improvement Program database was queried for Medicare patients (≥ 65 years) undergoing outpatient THA. Short-term complications, LOS, and discharge destination were evaluated. Multivariate logistic regression was used to evaluate risk factors for complications, failed SDD, reoperation, readmission, and non-home discharge disposition. Overall, 2,063 THAs were included. Complication rate was 7.4%. The number of patients staying in the hospital ≥ 1 day was 1,080 (52%). A total of 151 patients (7.3%) experienced a non-home discharge. Predictors for having any complication was an extended LOS ≥ 1 day (odds ratio [OR] 2.86), p < 0.001. Significant predictors for failed SDD were smoking history (OR 2.25), operative time ≥ 82 minutes (OR 1.98), American Society of Anesthesiologists Class > II (OR 1.67), and age ≥ 71 (OR 1.31) (all p ≤ 0.004). Significant predictors for a non-home discharge were LOS ≥ 1 day (OR 13.71), American Society of Anesthesiologists Class > II (OR 2.36), age ≥ 71 (OR 2.07), operative time ≥ 82 minutes (OR 1.88), and female gender (OR 1.81), all p ≤ 0.003. The current study identifies the incidence, risk factors, and clinical impact of postoperative complications and prolonged LOS in Medicare-aged patients undergoing outpatient THA. Providers should consider preoperatively risk stratifying patients to reduce the costs associated with extended LOS, complication, and unplanned discharge destination.
10.24.4 Product Subclass 4: Pyrazino[1,2-a]indoles and Related Benzo-Fused Ring Systems
Authors: Harris P. A.
Published: September 2021

The synthesis of pyrazino[1,2-a]indoles and related indolo[1,2-a]quinoxalines and pyrido[2′,1′:3,4]pyrazino[1,2-a]indol-5-ium salts are reviewed in this chapter. The most common routes to pyrazino[1,2-a]indoles involve cyclization of indole derivatives containing a formyl, keto, ester, or nitrile function at the 2-position. Indolo[1,2-a]quinoxalines are most readily accessed via cyclization of 1-(aryl)-1H-indoles, where the aryl group is substituted at the 2-position by either amino, iodo, or nitro functionality.
Modeling the physics of an electron-beam generated plasma through a rigid-beam approximation
Authors: Green Leigh Ann
Published: September 2021

A new model predicts the plasma created when an intense electron beam is injected into gas.
Time integrator agnostic charge conserving finite element PIC
Authors: O'Connor Scott , Crawford Zane D. , Ramachandran O. H. , Luginsland John , Shanker B.
Published: September 2021

Developing particle-in-cell (PIC) methods using finite element basis sets, and without auxiliary divergence cleaning methods, was a long-standing problem until recently. It was shown that if consistent spatial basis functions are used, one can indeed create a methodology that was charge conserving, albeit using a leapfrog time stepping method. While this is a significant advance, leapfrog schemes are only conditionally stable and time step sizes are closely tied to the underlying mesh. Ideally, to take full advantage of advances in finite element methods (FEMs), one needs a charge conserving PIC methodology that is agnostic to the time stepping method. This is the principal contribution of this paper. In what follows, we shall develop this methodology, prove that both charge and Gauss' laws are discretely satisfied at every time step, provide the necessary details to implement this methodology for both the wave equation FEM and Maxwell solver FEM, and finally demonstrate its efficacy on a suite of test problems. The method will be demonstrated by single particle evolution, non-neutral beams with space-charge, and adiabatic expansion of a neutral plasma, where the Debye length has been resolved, and real mass ratios are used.
All-solid-state bipolar pulsed generator based on linear transformer driver and push–pull circuit
Authors: Sun Guoxiang , Wang Xia , Shen Saikang , Li Lanxi , Shang Tianyi , Ding Weidong
Published: September 2021

All-solid-state linear transformer drivers (LTDs) are widely used in high-voltage repetitive nanosecond-pulsed generators, and only a few LTD generators can output bipolar rectangular waves currently. Furthermore, owing to the large reverse overshoot when the output pulse width is long, fewer LTD generators can achieve a rectangular wave output with a microsecond pulse width. In this study, a bipolar LTD circuit topology based on a push–pull circuit is proposed for irreversible electroporation. In this topology, a single-stage LTD module has four push–pull branches in its primary winding to achieve a bipolar output and a short-circuited winding with two resistor–capacitor–diode snubbers to suppress forward/reverse overshoot. A single-stage LTD module and a 12-stage LTD have been tested, and the results show that they can output bipolar rectangular pulses with variable parameters. When the output pulse width is 100 ns to 1 µs, the maximum output voltage amplitude is 5.74 kV, the rise time is 29.1 ns, and the reverse overshoot at 1 µs is 2.9%. When the output pulse width is 1–8 µs, the maximum output voltage amplitude is 2.93 kV, the rise time is 24.3 ns, and the reverse overshoot at 8 µs is 11.3%.
A method for calculating the nonequilibrium entropy of a flowing polymer melt via atomistic simulation
Authors: Edwards Brian J. , Nafar Sefiddashti M. Hadi , Khomami Bamin
Published: September 2021

Nonequilibrium thermodynamics as applied to polymeric liquids is limited by the inability to quantify the configurational entropy. There is no known experimental method to determine it rigorously. Theoretically, entropy is based entirely on the configurational microstate of the material, but for polymer liquids, the number of available configurations is immense and covers long length scales associated with the chain-like nature of the constituent molecules. In principle, however, it should be possible to calculate the entropy from a realistic molecular dynamics simulation that contains positional data for each atomic unit making up the polymer macromolecules. However, there are two challenges in calculating the entropy from an atomistic simulation: it is necessary to relate atomic positions to configurational mesostates, depending on the degree of coarse-graining assumed (if any), and then to entropy, and considerable computational resources are required to determine the three-dimensional probability distribution functions of the configurational mesostates. In this study, a method was developed to calculate nonequilibrium entropy using 3d probability distributions for a linear, entangled polyethylene melt undergoing steady-state shear and elongational flow. An approximate equation expressed in terms of second moments of the 3d distributions was also examined, which turned out to provide almost identical values of entropy as the fully 3d distributions at the mesoscopic level associated with the end-to-end vector of the polymer chains.
Design and implementation of plasma electron density measurements based on FPGA with all-phase FFT for tokamak devices
Authors: Shu Shuangbao , Lai Jin , Chen Zhiqiang , Wang Yong , Zhang Yuzhong , Tao Xiaojie , Lang Xianli , Chen JingJing
Published: September 2021

Plasma electron density is one of the most fundamental parameters when studying tokamak plasma physics, which is widely used in plasma control systems and plasma physics analyses. A hydrogen cyanide laser interferometer is generally applied to measure the plasma electron density in many tokamak devices. Therein, the plasma electron density is calculated by measuring the phase difference between the reference signal and the detector signal. This work provides a new way to realize real-time measurements of the plasma electron density with a phase comparator and processing system based on a field-programmable gate array chip. The system integrates a signal processing module, an all-phase fast Fourier transform (ap-FFT) module realized via matrix operations and phase comparisons, and a network communication module all in one board. This work concludes that the ap-FFT is robust and accurate for phase calculations compared with a windowing FFT. A data-reuse method and a phase shift method are proposed to improve the time resolution and phase range. The phase error is less than 0.1° and the time resolution is 0.025 ms, which is better than hardware methods and traditional software methods. This system is highly flexible with reduced design costs to meet the requirements of a tokamak, which can provide a valuable reference for other tokamak and phase difference comparisons.
Entropy stabilized off-stoichiometric cubic γ-Cu1−xIx phase containing high-density Cu vacancies
Authors: Ahn Kyunghan , Kim Myung-Gil , Park Sungjin , Ryu Byungki
Published: September 2021

Copper iodide (CuI) has gained attention as a highly conductive p-type transparent material. Here, we investigate the phase stability of I-rich cubic CuI phases with Cu-vacancy defects by performing hybrid-density functional theory calculations. In the Cu-rich equilibrium condition, the nearly stoichiometric phase is the ground state with quenched Cu-vacancy defects, and the Cu-vacancy defect is a major acceptor responsible for the intrinsic p-type conductivity. In contrast, in the I-rich condition, the off-stoichiometric Cu1−xIx phase (x = 0.5–0.55) containing high-density Cu vacancies is stabilized with configuration entropy from Cu vacancies. As the off-stoichiometric phases contain high-density neutral Cu vacancies, the hole transport can be hindered, and the hole mobility could be reduced.
Miniaturized metamaterial absorber based on a high permittivity substrate
Authors: Anjali M. , Stephen Lincy , Subramanian V.
Published: September 2021

Electromagnetic metamaterial absorbers are an efficient replacement for the conventional absorbers due to their advantages like compact thickness, user control of frequency, etc. This work explores the development of a metamaterial absorber using a specifically synthesized substrate. Compared with commercially available substrate boards, a thoroughly designed substrate provides additional control over the absorber properties as it can have a dielectric constant and loss tangent of choice. This paper introduces a novel ceramic, Ba3Fe10Ti18O54 (BFT), as a substrate for a metamaterial absorber having permittivity, ɛr ∼ 22.3, at X-band frequency. The high dielectric constant results in a miniaturized metamaterial absorber with the dimensions λ/8 × λ/7 × λ/28. The proposed absorber produces 97.4% absorption at 10.65 GHz, which is studied numerically and experimentally. Absorption above 90% for the proposed structure has a bandwidth of 0.75 GHz. The broad nature with a simple topological structure can be attributed to the presence of dielectric and magnetic loss in the substrate. The absorption mechanism is explained with impedance and surface current analysis. Further, absorption characteristics are analyzed with the different thicknesses of the substrate.
Diagrammatics of tunable interactions in anisotropic colloids in rotating electric or magnetic fields: New kind of dipole-like interactions
Authors: Komarov Kirill A. , Yurchenko Stanislav O.
Published: September 2021

Anisotropic particles are widely presented in nature, from colloidal to bacterial systems, and control over their interactions is of crucial importance for many applications, from self-assembly of novel materials to microfluidics. Placed in rapidly rotating external electric fields, colloidal particles attain a tunable long-range and many-body part in their interactions. For spherical colloids, this approach has been shown to offer rich capabilities to construct the tunable interactions via designing the internal structure of particles and spatial hodographs of external rotating fields, but in the case of anisotropic particles, the interactions remain poorly understood. Here, we show that tunable interactions between anisotropic rod-like and spheroidal colloidal particles in rotating electric or magnetic fields can be calculated and analyzed with the diagrammatic technique we developed in the present work. With this technique, we considered an in-plane rotating electric field, obtained the long-range asymptotics of the anisotropic interactions, calculated the tunable interactions between particles rotating synchronously, and found conditions for rotator repulsion. We compared the mechanisms providing tunable interactions to those for orientational (Keesom), induction (Debye), and dispersion (London) interactions in molecular systems and found that the tunable interactions between anisotropic particles represent a novel kind of dipole-like interaction. The method can be directly generalized for magnetically induced interactions, 3D systems, and fields with spatial hodographs. The results provide significant advance in theoretical methods for tunable interactions in colloids and, therefore, are of broad interest in condensed matter, chemical physics, physical chemistry, materials science, and soft matter.
Stimulated excitation of thermal diffusion waves in a magnetized plasma pressure filament
Authors: Karbashewski S. , Sydora R. D. , Van Compernolle B. , Poulos M. J.
Published: September 2021

Results are presented from basic heat transport experiments using a magnetized electron temperature filament that behaves as a thermal resonator. Using a small cathode source, low energy electrons are injected along the magnetic field into the afterglow of a pre-existing plasma forming a hot electron filament embedded in a colder plasma. A series of low amplitude, sinusoidal perturbations are added to the cathode discharge bias that creates an oscillating heat source capable of driving large amplitude electron temperature oscillations. Langmuir probes are used to measure the amplitude and phase of the thermal wave field over a wide range of driver frequencies. The results are used to verify the excitation of thermal waves, confirm the presence of thermal resonances, and demonstrate the diagnostic potential of thermal waves through measurement of the parallel thermal diffusivity.
Vibrational mode-specificity in the dynamics of the Cl + C2H6 → HCl + C2H5 reaction
Authors: Papp Dóra , Li Jun , Guo Hua , Czakó Gábor
Published: September 2021

We report a detailed dynamics study on the mode-specificity of the Cl + C2H6 → HCl + C2H5 H-abstraction reaction. We perform quasi-classical trajectory simulations using a recently developed high-level ab initio full-dimensional potential energy surface by exciting five different vibrational modes of ethane at four collision energies. We find that all the studied vibrational excitations, except that of the CC-stretching mode, clearly promote the title reaction, and the vibrational enhancements are consistent with the predictions of the Sudden Vector Projection (SVP) model, with the largest effect caused by the CH-stretching excitations. Intramolecular vibrational redistribution is also monitored for the differently excited ethane molecule. Our results indicate that the mechanism of the reaction changes with increasing collision energy, with no mode-specificity at high energies. The initial translational energy mostly converts into product recoil, while a significant part of the excess vibrational energy remains in the ethyl radical. An interesting competition between translational and vibrational energies is observed for the HCl vibrational distribution: the effect of exciting the low-frequency ethane modes, having small SVP values, is suppressed by translational excitation, whereas a part of the excess vibrational energy pumped into the CH-stretching modes (larger SVP values) efficiently flows into the HCl vibration.
Simplified derivation of the Kompaneets equation
Authors: Milonni Peter W.
Published: September 2021

An isotropic electromagnetic field in a plasma of thermalized electrons undergoes changes in energy as a result of Compton scattering and an Einstein–Hopf drag force on the electrons, eventually approaching a Bose–Einstein photon distribution at the electron temperature. The rate of change of field energy due to the combined effects of Compton scattering and the drag force is shown to be described by the Kompaneets equation for photon diffusion in frequency space. A similarity is noted between this approach and Einstein's derivation of the Planck spectrum based on the recoil of atoms as they absorb and emit radiation.
Koala retrovirus genetic diversity and transmission dynamics within captive koala populations
Authors: Joyce Briony A. , Blyton Michaela D. J. , Johnston Stephen D. , Young Paul R. , Chappell Keith J.
Published: September 2021

Significance

A conserved retrovirus, koala retrovirus (KoRV)-A, is present within the genome of koalas in most Australian populations. Additional divergent sequences and subtypes are thought to be exogenously transmissible and more pathogenic. We present a comprehensive analysis of KoRV genetic diversity within two captive koala populations and statistically significant evidence of exogenous transmission occurring primarily through maternal transmission. These findings suggest strategies which may help limit the spread of pathogenic KoRV subtypes. We raise the possibility that captive breeding programs could target use of antiretroviral drugs to dams during the breeding season. While substantial research is needed to demonstrate safety and effectiveness, this presents a potentially important conservation strategy for koala populations severely affected by disease and currently in rapid decline.
Legacy genetics of
Arachis cardenasii
in the peanut crop shows the profound benefits of international seed exchange
Authors: Bertioli David J. , Clevenger Josh , Godoy Ignacio J. , Stalker H. T. , Wood Shona , Santos Joáo F. , Ballén-Taborda Carolina , Abernathy Brian , Azevedo Vania , Campbell Jacqueline , Chavarro Carolina , Chu Ye , Farmer Andrew D. , Fonceka Daniel , Gao Dongying , Grimwood Jane , Halpin Neil , Korani Walid , Michelotto Marcos D. , Ozias-Akins Peggy , Vaughn Justin , Youngblood Ramey , Moretzsohn Marcio C. , Wright Graeme C. , Jackson Scott A. , Cannon Steven B. , Scheffler Brian E. , Leal-Bertioli Soraya C. M.
Published: September 2021

Significance

A great challenge for humanity is feeding its growing population while minimizing ecosystem damage and climate change. Here, we uncover the global benefits arising from the introduction of one wild species accession to peanut-breeding programs decades ago. This work emphasizes the importance of biodiversity to crop improvement: peanut cultivars with genetics from this wild accession provided improved food security and reduced use of fungicide sprays. However, this study also highlights the perilous consequences of changes in legal frameworks and attitudes concerning biodiversity. These changes have greatly reduced the botanical collections, seed exchanges, and international collaborations which are essential for the continued diversification of crop genetics and, consequently, the long-term resilience of crops against evolving pests and pathogens and changing climate.
Submersed micropatterned structures control active nematic flow, topology, and concentration
Authors: Thijssen Kristian , Khaladj Dimitrius A. , Aghvami S. Ali , Gharbi Mohamed Amine , Fraden Seth , Yeomans Julia M. , Hirst Linda S. , Shendruk Tyler N.
Published: September 2021

Significance

Methods to manipulate and control the dynamics of spontaneously flowing active materials are vital if these fluids are to lead to technological applications. We report the development of an easy-to-implement technique to achieve tunable, local control over active nematic films, the preeminent example of active fluids. We establish that micropatterns, fully submersed below active films, have a pronounced impact on dynamics. To showcase the adaptability of our technique, we present four proof-of-concept microstructures: trenches, undulated sinusoids, stairways, and pillars. Each illustrates a particular strength of our approach, including enacting abrupt virtual boundaries to trap topological defects, separating distinct flow states at constant levels of biochemical fuel, gently guiding self-propelled defects, and modifying local active nematic composition.
Identifying extracellular vesicle populations from single cells
Authors: Nikoloff Jonas M. , Saucedo-Espinosa Mario A. , Kling André , Dittrich Petra S.
Published: September 2021

Significance

Extracellular vesicles (EVs) are omnipresent in humans and contribute to the intercellular communication between cells. Their content, size, quantity, and surface markers depend on their cytosolic origin and the protein complex involved in membrane trafficking. Hence, vesicles may serve as valuable biomarkers, accessible via liquid biopsies. As of today, however, phenotype-specific EV subpopulations have not been clearly identified, mainly because EVs can be taken up and modified by other cells, hindering the heterogeneous EV production of individual cells. The proposed method enables robust classification of the EVs secreted by single cells, assessing their heterogeneity with respect to surface markers. In the future, this tool can be employed to assess the release and uptake dynamics of EVs in a controlled environment.
Engineered SARS-CoV-2 receptor binding domain improves manufacturability in yeast and immunogenicity in mice
Authors: Dalvie Neil C. , Rodriguez-Aponte Sergio A. , Hartwell Brittany L. , Tostanoski Lisa H. , Biedermann Andrew M. , Crowell Laura E. , Kaur Kawaljit , Kumru Ozan S. , Carter Lauren , Yu Jingyou , Chang Aiquan , McMahan Katherine , Courant Thomas , Lebas Celia , Lemnios Ashley A. , Rodrigues Kristen A. , Silva Murillo , Johnston Ryan S. , Naranjo Christopher A. , Tracey Mary Kate , Brady Joseph R. , Whittaker Charles A. , Yun Dongsoo , Brunette Natalie , Wang Jing Yang , Walkey Carl , Fiala Brooke , Kar Swagata , Porto Maciel , Lok Megan , Andersen Hanne , Lewis Mark G. , Love Kerry R. , Camp Danielle L. , Silverman Judith Maxwell , Kleanthous Harry , Joshi Sangeeta B. , Volkin David B. , Dubois Patrice M. , Collin Nicolas , King Neil P. , Barouch Dan H. , Irvine Darrell J. , Love J. Christopher
Published: September 2021

Significance

Most of the global population resides in low- and middle-income countries, where current vaccines for COVID-19 remain largely unavailable. For the COVID-19 pandemic, the world will need access to >10 billion doses of vaccines, or more than double the annual volume of vaccines for all other diseases. Many vaccine candidates use the SARS-CoV-2 receptor-binding domain (RBD) antigen. Here, we present an engineered RBD with improved production titers in
Pichia pastoris
, a yeast commonly used for large-scale, low-cost manufacturing by vaccine manufacturers. The modified RBD also raises an enhanced immune response in mice relative to the Wuhan-Hu-1 sequence used in current candidates. These combined traits make it a promising candidate for next-generation vaccines addressing emerging variants of the virus.