bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in human 3D trunk shape and its functional implications in hominin evolution
Authors: Bastir Markus , González Ruíz José María , Rueda Javier , Garrido López Gonzalo , Gómez-Recio Marta , Beyer Benoit , San Juan Alejandro F. , Navarro Enrique
Published: July 2022

This study investigates the contribution of external trunk morphology and posture to running performance in an evolutionary framework. It has been proposed that the evolution from primitive to derived features of torso shape involved changes from a mediolaterally wider into a narrower, and antero-posteriorly deeper into a shallower, more lightly built external trunk configuration, possibly in relation to habitat-related changes in locomotor and running behaviour. In this context we produced experimental data to address the hypothesis that medio-laterally narrow and antero-posteriorly shallow torso morphologies favour endurance running capacities. We used 3D geometric morphometrics to relate external 3D trunk shape of trained, young male volunteers (N = 27) to variation in running velocities during different workloads determined at 45–50%, 70% and 85% of heart rate reserve (HRR) and maximum velocity. Below 85% HRR no relationship existed between torso shape and running velocity. However, at 85% HRR and, more clearly, at maximum velocity, we found highly statistically significant relations between external torso shape and running performance. Among all trained subjects those with a relatively narrow, flat torso, a small thoracic kyphosis and a more pronounced lumbar lordosis achieved significantly higher running velocities. These results support the hypothesis that external trunk morphology relates to running performance. Low thoracic kyphosis with a flatter ribcage may affect positively respiratory biomechanics, while increased lordosis affects trunk posture and may be beneficial for lower limb biomechanics related to leg return. Assuming that running workload at 45–50% HRR occurs within aerobic metabolism, our results may imply that external torso shape is unrelated to the evolution of endurance running performance.
A pilot investigation of genetic and epigenetic variation of FKBP5 and response to exercise intervention in African women with obesity
Authors: Willmer Tarryn , Oosthuizen Amberly , Dias Stephanie , Mendham Amy E. , Goedecke Julia H. , Pheiffer Carmen
Published: July 2022

We investigated gluteal (GSAT) and abdominal subcutaneous adipose tissue (ASAT) DNA methylation of FKBP5 in response to a 12-week intervention in African women with obesity, as well as the effect of the rs1360780 single nucleotide polymorphism (SNP) on FKBP5 methylation, gene expression and post-exercise training adaptations in obesity and metabolic related parameters. Exercise (n = 19) participants underwent 12-weeks of supervised aerobic and resistance training while controls (n = 12) continued their usual behaviours. FKBP5 methylation was measured in GSAT and ASAT using pyrosequencing. SNP and gene expression analyses were conducted using quantitative real-time PCR. Exercise training induced FKBP5 hypermethylation at two CpG dinucleotides within intron 7. When stratified based on the rs1360780 SNP, participants with the CT genotype displayed FKBP5 hypermethylation in GSAT (p < 0.05), and ASAT displayed in both CC and CT carriers. CC allele carriers displayed improved cardiorespiratory fitness, insulin sensitivity, gynoid fat mass, and waist circumference (p < 0.05) in response to exercise training, and these parameters were attenuated in women with the CT genotype. These findings provide a basis for future studies in larger cohorts, which should assess whether FKBP5 methylation and/or genetic variants such as the rs1360780 SNP could have a significant impact on responsiveness to exercise interventions.
Accelerating error correction in tomographic reconstruction
Authors: Ali Sajid , Otten Matthew , Di Z. W.
Published: July 2022

Spurred by recent advances in detector technology and X-ray optics, upgrades to scanning-probe-based tomographic imaging have led to an exponential growth in the amount and complexity of experimental data and have created a clear opportunity for tomographic imaging to approach single-atom sensitivity. The improved spatial resolution, however, is highly susceptible to systematic and random experimental errors, such as center of rotation drifts, which may lead to imaging artifacts and prevent reliable data extraction. Here, we present a model-based approach that simultaneously optimizes the reconstructed specimen and sinogram alignment as a single optimization problem for tomographic reconstruction with center of rotation error correction. Our algorithm utilizes an adaptive regularizer that is dynamically adjusted at each alternating iteration step. Furthermore, we describe its implementation in a software package targeting high-throughput workflows for execution on distributed-memory clusters. We demonstrate the performance of our solver on large-scale synthetic problems and show that it is robust to a wide range of noise and experimental drifts with near-ideal throughput.
Porous organic polymers for CO2 reduction
Authors: Razzaque Shumaila , Razzaq Humaira
Published: July 2022

The development of a green society with low CO2 emissions is a sustainable developmental goal. The catalytic fixation of CO2 into value-added chemicals has attracted worldwide attention. Among various strategies, catalytic conversion is the most pronounced methodology to reduce CO2 emissions. In contrast to other pollutants, CO2 is a valuable feedstock for producing value-added chemicals. Numerous homogenous and heterogeneous catalysts are employed to ease the transformation. Compared to homogenous catalysis, heterogeneous catalysis has more beneficial aspects due to the ease of separation and reusability. Among the various heterogeneous catalysts, POPs are versatile materials that have potential in CO2 capture and subsequent transformation.
Recent progress in water remediation and dye removal on one-dimensional nanomaterials
Authors: Shamraiz Umair , Raza Bareera , Badshah Amin , Haneef Zahid , Ali Muhammad Ashfaq
Published: July 2022

One-dimensional nanomaterials possess diverse functional and structural properties. Hence, they have been employed broadly in various catalytic fields including, water splitting, CO2 capture, photodegradation of dyes, supercapacitors, metal-ion batteries, and solar cells. Various 1D nanomaterials have been synthesized in the past few years with different morphologies and sizes. Compared to other higher dimensional materials, these 1D materials have been given prominence due to their larger surface area, high aspect ratio, and better electronic transport. In this chapter, we have selectively discussed the dye degradation on 1D Ti, Zn, Cd, and Cu-based photocatalysts. This chapter highlights the intriguing factors that should be considered in designing new photocatalysts, including higher surface area, aspect ratio, and the optimized concentrations of the dopants.
Current progress on the graphene-based nanocomposites for medical, environmental and energy applications
Authors: Khalil Ali Talha , Iqbal Javed , Abbasi Banzeer Ahsan , Ullah Ikram , Yaseen Tabassum , Khan Imran , Ayaz Muhammad , Ahmad Irshad
Published: July 2022

The versatile chemistry of graphene offers new avenues for its functionalization, and through such approaches, graphene-based materials are driving exciting applications in science. In addition to its biocompatibility, graphene is known for its excellent optical, electronic, mechanical, spintronic and other physicochemical features, making them a candidate for a wide array of applications. Present work on graphene materials relates to the exploration of its derivatives and functionalization with different metals, polymers etc. In the current contribution, we have briefly discussed the current status of research on graphene and graphene–metal-based composite materials in different fields like medicine, environment, and energy systematically.
Nanotechnology for CO2 reduction: progress and perspective
Authors: de Souza Felipe , Gupta Ram K.
Published: July 2022

The ever-growing concern regarding environmental issues is prompting the development of new technologies that can be more sustainable and effective. The increase of CO2 emission due to anthropic action is one of the most discussed themes in this regard. This book chapter discusses the progress, and opportunities nanotechnology can provide to chemically reduce CO2. The chemical conversion of CO2 into value-added materials simultaneously decreases its emission and provides low-cost starting materials for many applications. Various topics such as photo, electro, bio, and thermal reduction of CO2 have been covered, emphasizing the concepts, materials, examples from the literature, and latest hurdles. Also, an entire session is devoted to explaining the basic spectroscopic characterizations used in CO2 reduction to provide a clear picture and the latest advancement in characterizations. It is expected that the discussions in this chapter can enrich the knowledge on various approaches for CO2 reduction as well as generate new ideas.
“Plug and Play” diagnostic systems with optoelectronic nanosensors
Authors: Achadu Ojodomo J. , Wan Chaoying , Park Enoch Y.
Published: July 2022

Diagnostics are a vital component of the healthcare system and provide pivotal information influencing practitioners’ decisions regarding disease identification, treatment, and management. With advances in nanotechnology over the last few decades, nanotechnology-assisted diagnostics and nanosensors design have become an even more integral part of medical practice today, enabling, for example, more personalized and productive treatments and diseases prevention. As chemical and biological testing capabilities continue to evolve rapidly with the development of new technologies and more advanced approaches, certain concepts and techniques underpin reliable and effective clinical detections. One of these techniques is optical spectroscopy which has stood the test of time and is widely used to assess the effectiveness of old and emerging techniques, making it quite fundamental and immutable. Here, we discuss the optical and electrochemical systems of diagnostic testing and the nanotechnological progress in terms of processes and innovative materials being driven into diagnostic technologies today. Particularly, the emerging research that will lead to a new wave of “plug and play” diagnostic devices suitable for commercial optoelectronic nanobiosensors role with self-powered capabilities and point-of-care (POC) applications through the intervention of advanced functional nanomaterials.
Nanotoxicity to nanomedicine: applications of engineered nanomaterials, regulatory challenges and opportunities
Authors: Kumawat Mamta , Saini Anamika , Revaprasadu Neerish , Umapathi Akhela , Daima Hemant Kumar
Published: July 2022

Nanotechnology is a multidisciplinary field implicated in high regard in medicine. The history of nanotechnology speaks about the potential uses of nanoparticles for decorative purposes and the treatment of different diseases. However, many potential innovations face hindrance at the laboratory level due to nanotoxicological issues. Therefore, it is important to understand the toxicity of nanomaterials and control it at the cellular level through the smart engineering of nanomaterials and accordingly manage pharmacological properties. Due to recent developments, nanomedicine has contributed immensely to disease -diagnostics, -prevention, -imaging, and -treatments. Therefore, in this chapter, we have tried to understand nanotoxicity by exploring the outcomes of various historical toxicity studies and existing laboratory techniques. We have also discussed some of the successful commercial nanomedicines available for various diseases and explored essential properties of nanomaterial beneficial for smart-multifunctionality of nanomedical applications. Further, to provide strict regulation over the rampant usage of nanomaterials, country-specific prominent regulatory bodies such as the Food and Drug Administration and the National Institute of Occupational Safety and Health Administration have laid out several guidelines and protocol documents, which are discussed. The chapter also contains specific regulatory problems faced in in vitro, in vivo, and in silico methods of nanomaterials usage. In the end, the chapter argues about the prospects of nanomedicine through the regulation of nanotoxicity.
Well-orchestrated physico-chemical and biological factors for enhanced secretion of osteogenic and angiogenic extracellular vesicles by mesenchymal stem cells in a 3D culture format
Authors: Holkar Ketki , Kale Vaijayanti , Ingavle Ganesh
Published: July 2022

Unlike the 2D culture, 3D culture is better known for simulating in vivo cellular behaviour through orchestrating interactions between cells and their surrounding microenvironments, resulting in enhanced extracellular vesicles (EVs) prodcution.
Integration of H2V3O8 nanowires and a GaN thin film for self-powered UV photodetectors
Authors: Dou Yi , Liang Yujun , Li Haoran , Xue Yali , Ye Hanlin , Han Yongsheng
Published: July 2022

A self-powered ultraviolet (UV) photodetector was successfully constructed through combining H2V3O8 nanowires (NWs) and a GaN thin film.
Correction: Polymorphism and solid–solid phase transitions of hydrogen bonded 2-adamantanol and 2-methyl-2-adamantanol compounds
Authors: Salvatori Alejandro , Negrier Philippe , Massip Stephane , Muñoz-Duque Antonio , Lloveras Pol , Barrio Maria , Tamarit Josep-Lluís
Published: July 2022

Correction for 'Polymorphism and solid–solid phase transitions of hydrogen bonded 2-adamantanol and 2-methyl-2-adamantanol compounds' by Alejandro Salvatori et al., CrystEngComm, 2022, 24, 3692–3700, https://doi.org/10.1039/D2CE00324D.
A path integral molecular dynamics study on the NH4+ rotation in NH4+⋯XH2 (X = Be or Mg) dihydrogen bond systems
Authors: Udagawa Taro , Kinoshita Amane , Kuwahata Kazuaki , Tachikawa Masanori
Published: July 2022

Thermal and nuclear quantum effects in NH4+⋯BeH2 and NH4+⋯MgH2 dihydrogen bond complexes are investigated using the path integral molecular dynamics method.
Insights into 2D materials
Authors: Zhao Hui , Ryu Sunmin
Published: July 2022

This themed collection includes a collection of articles providing new insights into 2D materials.
Quantum yield enhancement in the photocatalytic HCOOH decomposition to H2 under periodic illumination
Authors: Wong Sie Shing , Hülsey Max Joshua , An Hua , Yan Ning
Published: July 2022

Despite numerous studies on controlled periodic illumination to improve the quantum yield of photocatalytic reactions, debates still exist on the nature of such effect. In our system, we proposed that enhanced electron transfer is the promotion mechanism.
Silver decorated nickel–cobalt (oxy)hydroxides fabricated via surface reconstruction engineering for boosted electrocatalytic oxygen evolution and urea oxidation
Authors: Liu Shan-Shan , Xu Xiu-Feng , Li Ji-Sen
Published: July 2022

Surface reconstruction engineering is proposed to construct silver nanoparticle-loaded nickel–cobalt (oxy)hydroxides, which shows significantly enhanced catalytic OER and UOR performance along with long-term stability.
A copper(ii) coordination compound under water-oxidation reaction at neutral conditions: decomposition on the counter electrode
Authors: Mousazade Younes , Nandy Subhajit , Bikas Rahman , Aleshkevych Pavlo , Chae Keun Hwa , Siczek Milosz , Lis Tadeusz , Allakhverdiev Suleyman I. , Najafpour Mohammad Mahdi
Published: July 2022

The decomposition of a copper(ii) coordination compound (CuL3 (compound 1), L: 2,2′-bipyridine N,N′-dioxide) during the oxygen-evolution reaction on the surface of a counter electrode is investigated.
Palladium decoration directed synthesis of ZIF-8 nanocubes with efficient catalytic activity for nitrobenzene hydrogenation
Authors: Zhao Xiaojing , Lu Xiaoxiao , Chen Wen-Jie , Liu Yubin , Pan Xiaoyang
Published: July 2022

By using H2PdCl4as a novel structure-directing agent, the shape of ZIF-8 is transformed from rhombic dodecahedron to cube. After H2treatment, the as-obtained Pd/ZIF-8 nanocubes show efficient catalytic activity for nitrobenzene hydrogenation.
Fabrication of a donkey spleen ferritin–pectin complex to reduce iron release and enhance the iron supplementation efficacy
Authors: Sun Mingyang , Gan Jing , Li Yuehuan , Dai Shuhan , Lv Chenyan , Zhao Guanghua
Published: July 2022

The interaction between donkey spleen ferritin and pectin at pH 5.0 can help inhibit the iron release from ferritin, and the donkey spleen ferritin–pectin complex has been proved to be an efficient iron supplement in vivo.
Depolymerization of post-consumer PET bottles with engineered cutinase 1 fromThermobifida cellulosilytica
Authors: Zhang Zixuan , Huang Shiming , Cai Di , Shao Chaofeng , Zhang Changwei , Zhou Junhui , Cui Ziheng , He Tianqi , Chen Changjing , Chen Biqiang , Tan Tianwei
Published: July 2022

The enhanced enzymatic activity and thermal stability of cutinase 1 fromThermobifida cellulosilyticaby enzyme engineering were utilized to achieve efficient degradation of post-consumer polyethylene terephthalate (PET) bottle particles.
Porous FeP/CoP heterogeneous materials as efficient alkaline oxygen evolution reaction (OER) catalysts
Authors: Lei Xiang , Qing Junchen , Weng Leiting , Li Shumei , Peng Ruzheng , Wang Wei , Wang Jinliang
Published: July 2022

Transition metal phosphides have been widely studied because of their low cost and good conductivity, attempting to replace precious metal-based materials as new electrochemical catalysts for oxygen evolution reaction.
Synthesis of bridgehead-azacycles via dual C–N/C–C annulation of α-amino acids, aminals and maleimides
Authors: Thadem Nagender , Rajesh Manda , Balaboina Harikrishna , Das Saibal
Published: July 2022

A rare dipolarophile-induced diastereo-selective amidative annulation and concomitant 3 + 2 cycloaddition are reported using α-amino acids, amino aldehydes and maleimides.
Highly-selective synthesis of functionalized spirobenzofuranones and diketones
Authors: Chen Yin-Jun , Xu Hui-Bei , Liu Hao , Dong Lin
Published: July 2022

A convenient and atom-economical rhodium(iii)-catalyzed highly-selective hydroacylation for the synthesis of spirobenzofuranones and diketones has been successfully developed.
Direct benzylic C–H difluoroalkylation with difluoroenoxysilanes by transition metal-free photoredox catalysis
Authors: Gui Jing , Sun Manman , Wu Haijian , Li Jinshan , Yang Jianguo , Wang Zhiming
Published: July 2022

A visible light promoted direct benzylic C–H difluoroalkylation with difluoroenoxysilanes catalyzed by Na2-eosin Y via a HAT-ORPC pathway has been developed, providing an efficient and atom-economic method for production of α-benzyl-α,α-difluoroketones.
Rapid electrochemical sensor for uranium(vi) assessment in aqueous media
Authors: Akl Zeinab F.
Published: July 2022

A new Schiff base was synthesized and applied as ionophore to construct potentiometric sensor for uranium(vi) determination.
Effective regulation of the electronic properties of a biphenylene network by hydrogenation and halogenation
Authors: Xie Yunhao , Chen Liang , Xu Jing , Liu Wei
Published: July 2022

The electronic properties of a biphenylene network can be effectively regulated in the range of 0.00–4.86 eV by hydrogenation and halogenation, and some of the obtained functionalized biphenylene networks have the potential to photolyse water.
Dual determination of nitrite and iron by a single greener sequential injection spectrophotometric system employing a simple single aqueous extract from Areca catechu Linn. serving as a natural reagent
Authors: Ponhong Kraingkrai , Siriangkhawut Watsaka , Lee Chang Young , Teshima Norio , Grudpan Kate , Supharoek Sam-ang
Published: July 2022

Dual determination of nitrite and iron was proposed by using a single greener sequential injection (SI) spectrophotometric system employing a simple single aqueous extract from Areca catechu Linn.
Ultra-thin flexible paper of BNNT–CNF/ZnO ternary nanostructure for enhanced solid-state supercapacitor and piezoelectric response
Authors: Rabani Iqra , Park Ye-Jee , Lee Je-Won , Tahir Muhammad Shoaib , Kumar Ajeet , Seo Young-Soo
Published: July 2022

Nanosized ZnO particles have been synthesized on cellulose nanofiber and boron nitride nanotube surfaces via a hydrothermal route to give a ternary nanostructure and explored flexible papers for the electrochemical and piezoelectric performance.
Ultrasonic methods for determining flows and velocity fields
Authors: Barraclough Veronika , Cizek Jan , Strob Miroslav , Novosad Jan , Pulec Jaroslav , Dancova Petra
Published: July 2022

This paper introduces research and development of a modern non-invasive device for determining flows and velocity fields. This device is based on the ultrasonic method. The measured fluid flow is surrounded by appropriate ultrasonic transmitters and receivers, which communicate with each other. A physical principle of this method consists in an interaction of sound waves with a flow, which generates a certain delay in sound waves transmission. The found quantity is thus time delay. The device is being designed as a flowmeter and with advanced and extended postprocessing as a tomograph, which reconstructs a 3D vector field for big volumes. This whole process requires the following: development of an appropriate design of the ultrasonic flowmeter and tomograph, testing the signal transfer and also various postprocessing methods on a measurement accuracy, building of a special verification experimental equipment and building of an electronic device as a control unit and data acquisition system.
An experimental analysis of droplet charging in a wind tunnel
Authors: Bartoš Ondřej , Huněk Adam
Published: July 2022

The aim of this paper is to introduce an experimental analysis of droplet charging that occurs due to liquid film atomization on two different surfaces. The atomization of the droplets from the liquid film at high speed is still not satisfactory understood. The phenomena can be found in steam turbines, wind turbines, aeroplanes and other technical applications. The liquid film atomization is associated with the electrostatic charge of the formed droplets. The paper describes the experiment when the coated and non-coated surfaces were tested for an estimation of the droplet size distribution function and the droplet charge. A new wind tunnel was developed for the study of liquid film atomization in similar conditions in steam turbines. The coarse droplets are formed in the steam turbine from the liquid films on the blades and inner casings. The coarse droplets formed on the non-moving blades don´t exactly follow the bulk flow and they collide with the moving blades. These collisions cause erosion and corrosion processes which have an unfavourable effect on the reliability and the efficiency of steam turbines. The tunnel is equipped with the standard instrumentation for the measurement of the flow properties and for the analysis of the size distribution function of the droplets. Two measurements methods were used to attain the size of the droplets, along with their photogrammetry and light scattering. The first tested surface is polished stainless steel and the second is the electrical isolating and hydrophobic coating. The results from the measurement suggest the possibility of the better understanding the erosion processes in steam turbines.
2D numerical investigation of liquid dispersion in rotating packed bed and its comparison with experimental measurements using high-speed camera
Authors: Elcner Jakub , Hajek Ondrej , Jicha Miroslav
Published: July 2022

Study deals with liquid dispersion of water in unstructured wire mesh of rotating packed bed, experimentally investigated using high speed camera. Dispersed water in outer region of rotating packed bed were captured by high-speed camera and droplet size were investigated using image processing. Numerical simulations were performed on two – dimensional plane with similar geometry characteristics (diameter and distance between each wire). Volume of fluid method was used to describe a multiphase behaviour of phenomena and turbulence was modelled using k-epsilon model. Results of both were compared on basis of frequency distribution of individual size fraction of dispersed water in outer region of rotating packed bed and its velocities. Discussion was focused on possibility of 2D numerical investigation and possibility of its comparison with experimental measurement.
Analysis of velocity distribution in an air flow through a thin perforated plate
Authors: Groma Adam , Kazda Adam , Kotek Michal , Jašíková Darina , Kuře Adam
Published: July 2022

Modelling air flow in a curved fine perforated plate region was performed by porous zone substitution. This approach significantly simplifies the observed process, thus various limitations appeared. PIV measurements on an experimental test rig were performed and compared with the results from CFD computations.
A dispersion of a droplet flow on crossing wires in an air counterflow
Authors: Hájek Ondřej , Cejpek Ondřej , Malý Milan , Prinz František , Jícha Miroslav
Published: July 2022

Liquid dispersion on a wire mesh is a phenomenon that is utilized in many industrial applications, such as rotating packed beds. It is a very simple method of liquid atomization without a need for complex nozzles. This research focuses on an elementary case of a liquid dispersion on a crossing of two wires. Experiments were carried out in a wind tunnel to elucidate the influence of counterflow air velocity on a liquid sheet and droplets. High-speed camera was used to capture the impact of droplets on the crossing. Images were then processed using MATLAB® addon PIVlab. The effect of the input parameters, including a liquid flow rate in the range of 3.8 to 12 kg/h and air flow velocity varying from 0 to 9 m/s on the angle and velocity of dispersed droplets downstream of the crossing, was investigated. Finally, a qualitative description of the dispersion was evaluated. Results show that with an increasing liquid flow rate, the droplets dispersed in a wider angle. On the other hand, the influence of the air counterflow is significant only for low liquid flow rates. The atomization rate, determined by the number of small droplets, was better for higher liquid flow rates.
Fluid flow measurement in air ducts under unsteady flow conditions - fundamentals
Authors: Jancik Ludek , Dancova Petra
Published: July 2022

Current methods for measuring fluid flow require a steady flow to achieve correct results. However, in practical applications, such a place is often not available and the measurement results obtained do not have the required reliability for further use. The project aims to design a methodology for measuring the flow in selected types of unsteady flow, focusing on the conditions in the ventilation ducts. The presented paper explains the state of the art in this field and identifies the most promising ways for further research. According to the results found in available sources, acceptable results with relative deviations of about 5 % can be obtained with an increased number of measurement points.
Software-based processing system for phase Doppler systems
Authors: Jedelsky Jan , Maly Milan , Cejpek Ondrej , Wigley Graham , Meyers James F.
Published: July 2022

A Monte Carlo simulation of Phase Doppler systems has been developed. It consists of three sections, the droplet flow description, generation of the photomultiplier signals and then their processing to determine droplet velocities and the time shift between the signals from the three scattered light detection apertures. With highly realistic Doppler bursts being simulated and processed, the question arises as to whether the signal processing software could be used to process ‘real-world’ experimental signals. In a preliminary assessment of its capabilities in such a situation, actual spray Doppler signals (from a Dantec fibre-based PDA system with a BSA signal processor) were recorded and used as input to the software signal processor. The signals from the three photomultipliers were input first into a Picoscope and then into the BSA processor. In this way droplet velocities and size estimates would be available from the BSA as control data. The signal outputs were taken as csv files, and input directly into the software signal processor. Initially the software determined the time location of the centre of each signal burst envelop. This approach was shown to measure signal delays from single cycle to multiple cycles. For this experiment, the software was modified by adding a zero-crossing approach to measure the single cycle delays. The introduction of this method should establish the accuracy of the complete software package in the real world as the results from the preliminary experiment show good agreement between the two techniques.
Optimization of the continuity of the aspherical production processes in asphericon s.r.o based on subsurface damage and microroughness analysis
Authors: Matoušek Ondřej , Sedláčková Karolína , Kuryshev Vladislav
Published: July 2022

In the paper is presented an analysis and optimization of the standardized sub-apertural grinding process used in the serial production in asphericon s.r.o. The monitored parameter was the depth of subsurface damage and surface microroughness. Tested were five grinding processes, which were automatically generated by the internal system, for five different diamond grit sizes (D151, D91, D64, D30, and D15). For evaluation of the depth of the defected layer was used modified wedge polishing method which is suitable for analysis of the rotationally symmetrical sub-apertural grinding processes [1]. For identifying the presence of the subsurface damage two methods were used. Defect detection using an optical microscope, as the broadly used and reliable method, and detection by standard ISO control to get the comparison with the method used in common serial production. The microroughness was measured using a white-light microscope concerning the used grinding tool and the amount of removed material. Within the experiment was found as the most effective two-step process uses D91 for rough grinding and D30 for fine grinding. D91 provides a very good removal characteristic with final subsurface damage of 44 µm which is possible to grind out using the D30 tool in two steps with final subsurface damage 22 µm in a total processing time of 137 minutes. This grinding process is timewise in best balance with 80 minutes long polishing process and therefore minimize the production cost. Result microroughness around 2 nm Sq in the fully polished zone is already limited by the polishing process. Using a finer grinding tool is not bringing improvement in the surface microroughness just shortening polishing time due to lower subsurface damage.
Lift measurement of airfoil AH93-157 from wall pressure distribution
Authors: Procházka Pavel , Skála Vladislav , Antoš Pavel , Popelka Lukáš , Fürst Jiří , Schmirler Michal
Published: July 2022

Measurement of the lift coefficient of the AH93-157 airfoil was performed by measuring the static pressure distribution on the wind tunnel walls along the test-section. A correlation was established between the lift coefficient value, determined by integrating the static pressure distribution on the wind tunnel walls, and the lift coefficient value, determined by integrating the static pressure distribution on the airfoil surface. This method is useful for easy and quick determination of the lift coefficient on a simple airfoil model without complicated static pressure tubing from the surface. The measurement was made within a closed test-section. The correlation relationship also eliminates the problem of the finite span and the effect of the side walls. Comparison of pressure distribution on airfoil with CFD was performed as well.
Experimental investigation of the wake behind a cooled cylinder
Authors: Pulec Jaroslav , Dančová Petra , Vinš Václav
Published: July 2022

An experimental channel intended for investigation of a wake behind a cooled cylinder was designed and constructed in this work. The setup is designed for measurements with air at low Reynolds numbers. The measuring techniques based on the standard visualization with a fog generator and the constant temperature anemometry (CTA) were used. The flow performance was investigated behind two cylinders placed inside a channel with square cross section. One cylinder was kept at a constant flow temperature, while the second cylinder could be cooled using a water circuit with a thermostatic bath. The dependency of the Strouhal number on the Reynolds number was evaluated and compared to the literature data and the empirical correlations. The concept of an effective temperature in a non-isothermal flow was also applied. Unfortunately, a considerable difference between the preliminary measurements and the literature data was detected. The air-flow was found to have unsatisfactory high turbulence intensity. Consequently, some modifications of the current channel design are proposed.
Automatic field measurement of groundwater discharges in a tunnel
Authors: Rálek Petr , Hokr Milan , Slavík Lubomír , Balvín Aleš
Published: July 2022

The paper describes a complex project of flow rate measurement applied for groundwater discharge into a tunnel, for both individual seepage points and the collection channel totalizing the flow. Various standard methods are used according to a large range of flow rate magnitudes (tipping bucket, danaid, V-shaped weir) with partial improvements and technical adaptations. Data collection is provided by individual measurement units with ethernet interface sending data to a database server through the internet. Experience of 10 years with several upgrades of either individual measurement or the electronic collection and transmission system is summarized.
CFD analysis of an anemometric sensor design for air flow measurement in a heat exchanger
Authors: Sedlacek Jan , Kus Michal , Strob Miroslav , Matas Richard
Published: July 2022

This paper focuses on the issue of flow measurement in automotive heat exchangers. The measurement is complicated due to the limited space in the heat exchanger area and the non-uniform velocity profile. Therefore, only some measuring techniques can be used, which must be adapted to the specific conditions. The paper presents the initial stages of the development of a sensor for measuring the flow in a heat exchanger. These are CFD simulations used to determine the nature of the flow around the sensor and verify its effect on the flow field in its surrounding and on the entire heat exchanger. The results of these initial simulations are presented and discussed.
Counter flow atomizer: Effect of the area ratio of the outlet orifice and the inlet air canal
Authors: Smutková Karolína , Malý Milan , Cejpek Ondřej , Jedelský Jan
Published: July 2022

The need to reduce the energy demand of processes also creates pressure to make atomizers more efficient. A promising development path could be counterflow atomizers (CFA). An atomizer, or synonymously a nozzle, is a device that turns a liquid into a spray. The CFA is a twin-fluid type of atomizer because both the liquid and the atomizing gas are fed into it. Initial results suggest that CFA is capable of the same quality of atomization but using half the air mass flow rate compared to conventional twin-fluids atomizers when operated at identical inlet pressure. This means half the energy requirements with the same efficiency. This atomizer also shows a great promise in the atomization of highly viscous substances such as waste-based fuels and biomass oils. In CFA, the air expands twice; first, at the discharge from the air inlet canal into the mixing tube, and second, at the discharge from the atomizer to the surrounding atmosphere. Therefore, one of the main control parameters is the area ratio of the exit orifice and the air inlet canal. This study experimentally investigates the effect of this ratio on the spray quality for two different CFA atomizers using Phase Doppler Anemometry (PDA), which provides the velocity and size of individual droplet in the spray. The atomizers were operated at the air inlet pressure of 100 and 200 kPa and gas-to-liquid mass (GLR) ratios of 5, 10 and 20%. The effect of the double expansion can be well observed in the pressure differences between the air inlet and the pressure inside the mixing tube. The length of the air counterflow insert had a significant effect on the atomizer performance. For the shorter counterflow channel, a minimal effect on flow was observed; this atomizer behaved like a conventional twin-fluid atomizer and all expansions occurred downstream of the exit orifice. The longer counterflow canal changed the internal expansion ratios, larger droplets, wider spray and higher discharge coefficients (Cd) were obtained.
Optimization of the polishing process on a polishing machine with horizontal overarm
Authors: Veselý Lukáš , Matoušek Ondřej , Vít Tomáš , Novosád Jan
Published: July 2022

Understanding the basic principles of polishing on machines with autorotating swing kinematics is important for the description and understanding of more advanced polishing technologies. The article deals with the theoretical and numerical analysis of the polishing process and its comparison with the experiment performed during the real process on the machine. The dependence of the mutual position of the tool and workpiece axes on the removal distribution within the polished surface was described and demonstrated
Experimental set up for the investigation of partial phase changes of phase change materials
Authors: Zálešák Martin , Bouchal Patrik , Ostrý Milan , Hejčík Jiří
Published: July 2022

Thermal energy storage with phase change materials (PCMs) has attracted a lot of attention in the last several decades. Most PCMs do not change phase at a constant temperature but rather in a certain temperature range. It means that the PCM need to transit through its phase change temperature range to fully change phase from the solid state to the liquid state and vice-versa. The situation, in which the phase transition begins and/or ends within the phase change temperature range (in the mushy zone), is usually called a partial phase transition (or a partial phase change). The partial phase transitions occur quite often in real-life thermal energy storage systems with PCMs; especially when a PCM has a wide phase change temperature range. The behavior of PCMs during the partial phase transitions is poorly understood at the moment, because the experimental techniques used for the characterization of PCMs (such as the differential scanning calorimetry – DSC) are difficult to apply for the study of partial phase transitions. The lack of knowledge in this area influences the accuracy of phase change simulation models. The main goal of the experimental investigations, described in the paper, was to obtain data for the development of a simulation model for partial phase changes. The experimental set up for the investigation of partial phase changes of PCMs has been proposed, assembled, and the pilot measurements have been conducted. The experimental set up consists of two water storage tanks (that can be maintained at different water temperatures), a water-PCM concentric tube type heat exchanger and a data acquisition system. The water flows through the central tube of the heat exchanger while the PCM is located in the annular space of the exchanger. The water storage tanks, maintained at the temperatures within the phase change temperature range of a PCM, allow for the investigations of the heat storage cycles consisting of partial phase changes.
MnVI-NP–Catalyzed Generation of Nitrile Oxides: Easy Access to Isoxazolines and Isoxazoles via Stereoselective 1,3-Dipolar Cyclo­addition Reactions
Authors: Khamarui Saikat , Saima Yasmin
Published: July 2022

The versatility and effectiveness of MnVI-NPs as a catalyst is examined for the generation of nitrile oxides from aldoximes and subsequent 1,3-dipolar cycloaddition reactions. This synthetic protocol features­ fast reaction convergence under benign reaction conditions, operational simplicity, and the use of inexpensive precursors; it avoids the use of acids or bases. The strategy offers excellent chemo-, regio-, and diastereoselectivity in the 1,3-dipolar cycloaddition reaction of in situ generated nitrile oxides with alkenes and alkynes.
External nasal dilator decreases N95 respirator-related respiratory effort and symptoms in gastrointestinal endoscopy unit staff
Authors: Khalid Asif , Thomas Christopher , Kingsley Michael , Vipperla Kishore , Dueker Jeffrey , Kreiss Christianna , Phillips Anna Evans , Das Rohit , Fasanella Kenneth , Ibinson James
Published: July 2022

Background and study aims N95-filtering facepiece respirators (FFR) use is associated with physiological changes and symptoms due to impaired nasal airflow and increased breathing resistance. We prospectively studied the effect of using an external nasal dilator (END) in gastroenterology laboratory (gastrointestinal lab) staff using N95FFR.

Patients and methods N95FFR qualitative saccharine fit testing was performed on study participants with and without an END. Prospective data collection and comparisons included: 1) survey of perceived symptoms and difficulty of performing one day of gastrointestinal procedures with N95FFR and 1 day of gastrointestinal procedures with END plus N95FFR in random sequence; and 2) vitals and respiratory belt plethysmography in ten gastroenterologists performing simulated colonoscopy while wearing a surgical mask (SM), N95FFR plus SM, END plus N95FFR plus SM for 20 minutes each in random sequence and rapid succession.

Results Twenty-nine of 31 participants passed the N95FFR and the END plus N95FFR fit test. Twenty-two participants (12 physicians; 11 males; mean age 44.1 years, range 31–61) performed 1 day of gastrointestinal procedures with an N95FFR and 1 day of gastrointestinal procedures with an END plus N95FFR. Significantly less difficulty with nasal breathing and severity of symptoms including breathing difficulty, headache, fatigue and frustration, occurred while using an END plus N95FFR. Respiratory plethysmography peak-to-trough measurement showed an increase during the N95FFR stage compared to the END plus N95FFR stage and the SM stage.

Conclusions N95FFR related respiratory changes and symptom development may be mitigated by END use.
Optimal Diagnostic Criteria and a Staging System for Otogenic Skull Base Osteomyelitis
Authors: Takahashi Kuniyuki , Morita Yuka , Ogi Manabu , Nonomura Yoriko , Kitazawa Meiko , Yagi Chihiro , Yamagishi Tatsuya , Ohshima Shinsuke , Izumi Shuji , Horii Arata
Published: July 2022

Objective Diagnostic criteria for otogenic skull base osteomyelitis (SBO) have been conflicting among researchers. We aimed to propose clinically useful diagnostic criteria and a staging system for otogenic SBO that is associated with infection control and mortality.

Design The present study is designed as a retrospective one.

Setting This study was conducted at the University Hospital.

Participants Thirteen patients with otogenic SBO who met the novel rigorous diagnostic criteria consisted of symptomatic and radiological signs on high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI). Simple refractory external otitis was not included. A staging system according to disease extent revealed by HRCT and MRI is proposed: lesions limited to the temporal bone (stage 1), extending to less than half (stage 2), exceeding the midline (stage 3), and extending to the whole of the clivus (stage 4). All patients received long-term antibiotic therapy. Patients were divided into infection-uncontrolled or -controlled groups based on symptoms, otoscopic findings, and C-reactive protein level at the last follow-up. The mean follow-up period was 27.7 months.

Main Outcome Measures Possible prognostic factors, such as immunocompromised status and symptoms, including cranial nerve palsy, pretreatment laboratory data, and treatments, were compared between the infection-uncontrolled and -controlled groups. Disease stages were correlated with infection control and mortality.

Results The infection-uncontrolled rate and mortality rate were 38.5 and 23.1%, respectively. There were no significant differences in possible prognostic factors between the infection-uncontrolled and -controlled groups. HRCT-based stages significantly correlated with infection control and mortality.

Conclusion We proposed here the clinically useful diagnostic criteria and staging systems that can predict infection control and prognosis of otogenic SBO.
Modified Tunneling (Capsule Modification Technique) for Subcutaneous Placement of Ventriculo-Peritoneal Shunt in Patients with Hydrocephalus: Technical Note
Authors: Wani Wajid Nazir , Samad Heena , Bodeliwala Shaam , Jagetia Anita , Singh Daljit
Published: July 2022

One of the first procedures that a neurosurgical resident/trainee assists and performs is the placement of a ventriculoperitoneal shunt, the commonest being the Chhabra shunt system. However, no modification has been done or proposed in performing this procedure keeping in mind the position of the chamber of the Chhabra shunt system. As the tunneller has to pass through the subcutaneous plane having tight adhesions, it is essential to have a proper and adequate space for the chamber. Utilization of instruments such as artery forceps or Penfield dissectors for the same results in the creation of inappropriate or a roughly estimated space, which is either inadequate, causing kinking of tubing, or too roomy that results in the peri-catheter collection of cerebrospinal fluid with the risk of infection.

We propose a novel method of utilizing a modified tunneller with a distal “Capsule” that provides just enough space both, at the appropriate distance and for adequate length, for the chamber to fit snugly and thus avoid procedure-related risks and complications as well as reduce the total duration of surgery, thereby decreasing the chances of infection.
Hypofractionated (2.75 Gy per fraction) versus Conventionally Fractionated Primary Radiotherapy for T2N0M0 Carcinoma of the Glottis
Authors: Kovarik Josef , Kelly Charles , Cunnell Michelle , Jamil Fatima , Iqbal Muhammad Shahid
Published: July 2022

Introduction Radiotherapy provides excellent outcome in early stage glottic cancer; however, the optimal radiotherapy dose fractionation remains unknown.

Objective To investigate the outcome of patients with T2N0M0 treated with either hypofractionated (HypoFxn) or conventionally fractionated radical (ConFxn) radiotherapy.

Methods According to our institutional protocol, patients with T2N0M0 glottic cancer can be treated either with ConfFxn or HypoFxn radiotherapy, as per clinician's and patient's choice, following shared decision making discussing the advantages and disadvantages of both modalities. A total of 77 patients with T2N0M0 squamous cell carcinoma of glottis treated with either HypoFxn 55Gy in 20 fractions (n = 19) or ConFxn 63 to 65Gy in 30 fractions (n = 58) were included.

Results With median follow-up of 3.4 years, there was no significant difference in disease-free survival (median: HypoFxn = 65.2 months, and ConFxn = 75.3 months; p = 0.874), local recurrence free survival rates (median: HypoFxn = 78.8 months vs. ConFxn = 81.2 months; p = 0.274), and overall survival (median: HypoFxn = 65.9 months vs. ConFxn = 67.7 months; p = 0.532). Elective neck irradiation was given to 43 patients, all in the ConFxn group, and this was associated with poorer local control (p = 0.027). The use of radiotherapy modality, three-dimensional conformal radiotherapy (3DRT) versus intensity modulated radiotherapy (IMRT), was not a prognostic factor (p = 0.36). In the HypoFxn group, grade III acute dysphagia requiring nasogastric tube was 16%, compared with 25% in the ConFxn group (p = 0.446).

Conclusion HypoFxn radiotherapy provides a comparable treatment outcome with acceptable toxicity. The addition of prophylactic irradiation of the neck lymph nodes has no impact on regional control.