bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of Flexible Wearable Band With Printed Sensors for Vital Sign Acquisition
Authors: Lall Pradeep , Jang Hyesoo , Hill Curtis , Creel Libby
Published: December 2020

Wearable electronics need a number of desirable attributes, such as being compact, flexible, and lightweight. Prior studies on reliability testing have examined the relationship between a flexible electronic and repetitive human body motions (i.e., stretching, bending, twisting, and folding). Such mechanical loads can cause fatigue failure in a wearable electronic. In regard to a wearable band, fatigue failure can be influenced by folding stress. This research study involved the assessment of wearable biometric bands that were calibrated and examined by a test device for folding reliability. The wearable band combines a biometric sensor unit, a micro-controller unit with a wireless connection, and a printed thermistor unit. The sensors have been calibrated by actual temperature and biometric signals. Furthermore, the folding test was conducted utilizing multiple boards. Due to multiple components and printed lines of the PCB, optical images were taken in order to confirm which parts failed and the reasons for the failures. An FEM analysis was conducted in order to understand how stress impacts the PCB and which parts are stressed during the folding process. Throughout the process, an equation was developed to predict the number of cycles necessary for reaching fatigue failure. Throughout this study, the fatigue failure analysis on folding reliability of the wearable biometric band was conducted using experimental analysis, microscopy analysis, and simulating analysis. The study provided further knowledge about the fatigue failure mechanism, which resulted from the prediction of fatigue life developed from the PCB.
Non-Perpendicular Orientation High-G Impact Reliability of Electronics Potted Assemblies
Authors: Lall Pradeep , Pandurangan Aathi Raja Ram , Suhling Jeff , Deep John
Published: December 2020

The Commercial electronics being used in defense and aerospace applications are being exposed to extreme environments including high-G shock conditions, which is not their intended purpose of use. Currently most of the board level testing is being done at horizontal zero degree drop angle. In real life drop scenarios, the angle of drop varies a lot. The damage accrued in the board interconnects and components and solder-joint interconnects, varies with the change in the drop angle. The reliability of the electronic components and interconnections of the solder-joint depends on the effect of drop angle on the test vehicle. The results acquired under these varying drop angle environments would be more relatable to the real life drop scenarios. The test vehicle is a circular PCB and two different configurations of the test vehicle are tested bare and potted. The boards are tested for three different drop angles of 0-degree, 30-degree and 60 degree. Two different shock levels are tested at each drop angle 10,000g and 25,000g. To predict the effect of drop angle on the test assembly, an explicit finite element model of the assembly has been created and simulated.
Numerical Analysis of Oil Immersion Cooling of a Server Using Mineral Oil and Al2O3 Nanofluid
Authors: Niazmand Amirreza , Murthy Prajwal , Saini Satyam , Shahi Pardeep , Bansode Pratik , Agonafer Dereje
Published: December 2020

Increased demand for computer applications has manifested a rise in data generation, resulting in high Power Density and Heat Generation of servers and their components, requiring efficient thermal management. Due to the low heat carrying capacity of air, air cooling is not an efficient method of data center cooling. Hence, the liquid immersion cooling method has emerged as a prominent method, where the server is directly immersed in a dielectric liquid. The thermal conductivity of the dielectric liquids is drastically increased with the introduction of non-metallic nanoparticles of size between 1 to 150 nm, which has proven to be the best method. To maintain the dielectric feature of the liquid, non-metallic nanoparticles can be added.

Alumina nanoparticles with a mean size of 80 nm and a mass concentration of 0 to 5% with mineral oil are used in the present study. The properties of the mixture were calculated based on the theoretical formula and it was a function of temperature. Heat transfer and effect of the nanoparticle concentration on the junction temperature of the processors using CFD techniques were simulated on an open commute server with two processors in a row. The junction temperature was studied for different flow rates of 0.5, 1, 2, and 3 LPM, at inlet temperatures of 25, 35, and 45 degrees Celsius. The chosen heatsink geometries were: Parallel plate, Pin fin, and Plate fin heatsinks.
Development of Process-Recipes for Multi-Layer Circuitry Printing With Z-Axis Interconnects Using Aerosol-Jet Nanoparticle Ink
Authors: Lall Pradeep , Narangaparambil Jinesh , Soni Ved , Miller Scott
Published: December 2020

Flexible electronics is a rapid emerging trend in consumer-electronics with ever-increasing applications showing feasibility of functionality with flexibility. Aerosol Jet printing technology has gained rapid acceptance for additive printing owing to non-contact deposition and ability to print on non-planar surfaces. Prior work on aerosol-jet print processes primarily focuses on single-layer printing, taking into account different parameters such as mass flow, line width, sintering conditions, and overspray. Flexible PCBs in complex applications are envisioned to be multi-layered, involving stacking of interconnections and connection between successive layers through use of z-axis connections. Aerosol-jet printing method allows the printing of interconnections with a number of inks including silver, copper, and carbon with fine lines and spaces in neighborhood of 10μm. Process recipes for manufacturing multilayer circuits and system scale-up methods are required. The objective of the paper is to establish process-recipes for z-axis interconnects and quantify process variability with Aerosol-jet print process needed for high volume scale-up. Conductive interconnects have been printed using the ultrasonic atomizer and the interlayer dielectrics have been printed using the pneumatic atomizer. The effect of thermal sintering on the performance of the printed circuits has been quantified through measurements of interconnect resistance and shear load to failure. This paper explores the printing of multi-layer upto 8 conductive layers. Sintering profile for lower resistance per unit length and higher shear load to failure was tested.
Process-Consistency in Additive Printed Multilayer Substrates With Offset-Vias Using Aerosol Jet Technology
Authors: Lall Pradeep , Goyal Kartik , Miller Scott
Published: December 2020

The transition of additive printed electronics into high-volume production requires process consistency to allow quality control of the manufactured product. Process recipes are needed for multilayer substrates with z-axis interconnects in order to enable complex systems. In this paper, process recipes have been developed through fundamental studies of the interactions between the process parameters and the mechanical-electrical performance achieved for multilayer substrates. The study reported in this paper focuses on printed vias also known as donut vias. Aerosol jet process parameters studied include carrier mass flow rate, sheath mass flow rate, exhaust mass flow rate, print speed, number of passes, sintering time and temperature, uv-intensity for uv-cure, and standoff height. The electrical performance has been quantified through the measurements of resistance. The mechanical performance has been quantified through measurement of shear load-to-failure. The effect of sequential build-up on the mechanical-electrical properties vs process parameters have been quantified for up tp 8-layers designs. The performance of 5-layer and 8-layer additively printed substrate designs and effect of multiple vias has been compared to assess process consistency.
Measurement consistency of dynamic stretching muscle stiffness evaluated using shear wave elastography: comparison among different stretched levels and ROI sizes
Authors: Liu Xiao , Yu Hong-Kui , Sheng Shu-Ya , Liang Si-Min , Lu Hao , Gu Li-Xian , Fu Pei , Pan Min
Published: December 2020

Aim: To investigate the reliability of quantitative analysis of dynamic stretching muscle stiffness using shear wave elas-tography (SWE), and to evaluate the influence of stretched levels and region of interest (ROI) sizes on the repeatability of SWE measurements. Materials and methods: SWE videos of the gastrocnemius medius were collected during ankle movement from plantar flexion (PF) 40° to dorsiflexion (DF) 30°. Shear wave imageswere collected of ankle angles at PF 25°, 0°, DF 15°, and DF 30°, representing the slack status, mildly stretched level, moderately stretched level, and maximal stretched level of the gastrocnemius medius, respectively. ROI circles with diameters of 2 mm, 5 mm, and 8 mm were applied to measure the shear modulus. Intra-observer, and inter-observer repeatability of the measurements were compared among different stretched levels and ROI sizes. Results: Twenty-one healthy volunteers were enrolled. Muscle stiffness increased as the ankle DF increased. Intraclass correlation coefficients (ICCs) of intra-observer and inter-observer repeatability obtained for ROI sizes of 2 mm, 5 mm and 8 mm indicated good to excellent repeatability at all stretched levels. Conclusions: Shear wave elastography appeared to be a reliable tool to evaluate the dynamic stretching muscle stiffness with satisfactory repeatability at various stretched levels of gastrocnemius medius. Good to excellent repeatability was found using different ROI sizes.
Age-Group Differences in Body Mass Index, Weight, and Height in Adults With Down Syndrome and Adults With Intellectual Disability From the United States
Authors: Agiovlasitis Stamatis , Jin Jooyeon , Yun Joonkoo
Published: December 2020

The authors examined if body mass index (BMI), weight, and height across age groups differ between adults with Down syndrome (DS) and adults with intellectual disability but without DS. They conducted secondary analyses of cross-sectional data from 45,803 individuals from the United States from 2009 to 2014 of the National Core Indicators Adult Consumer Survey across five age groups: 18–29, 30–39, 40–49, 50–59, and 60+ years. For both men and women with DS, BMI and weight increased between the 18- to 29- and the 30- to 39-year age groups and decreased thereafter. For both men and women with intellectual disability, BMI and weight increased between the 18- to 29- and the 30- to 39-year age groups, stayed about the same until the 50- to 59-year age group, and decreased thereafter. Height demonstrated a small but significant decrease with older age in all groups. These cross-sectional comparisons indicate that BMI and weight may start decreasing at a younger age in adults with DS than in adults with intellectual disability.
Effectiveness of Outdoor Exercise Parks on Health Outcomes in Older Adults—A Mixed-Methods Systematic Review and Meta-Analysis
Authors: Ng Yoke Leng , Hill Keith D. , Levinger Pazit , Burton Elissa
Published: December 2020

The objective of this systematic review was to examine the effectiveness of outdoor exercise park equipment on physical activity levels, physical function, psychosocial outcomes, and quality of life of older adults living in the community and to evaluate the evidence of older adults’ use of outdoor exercise park equipment. A search strategy was conducted from seven databases. Nine articles met the inclusion criteria. The study quality results were varied. Meta-analyses were undertaken for two physical performance tests: 30-s chair stand test and single-leg stance. The meta-analysis results were not statistically significant. It was not possible to conclude whether exercise parks were effective at improving levels of physical activity. The review shows that older adults value the benefits of health and social interaction from the use of exercise parks. Findings should be interpreted with caution due to the small sample sizes and the limited number of studies.
New Evidence in the Study of Shirking in Major League Baseball
Authors: Paulsen Richard J.
Published: December 2020

This paper uses Major League Baseball data to examine the relationship between years remaining on player contracts and player performance. There is a potential for moral hazard to arise in this principal–agent relationship as the player may choose a less than optimal level of effort from the perspective of team management when the player has many guaranteed years remaining. A player fixed-effects estimation strategy, which finds a significant negative relationship between years remaining and performance, is employed. The primary contribution of this work is to show that this relationship is due to shirking. Alternative explanations for this relationship, such as teams signing improving players to multiyear contracts or players facing an adjustment process when joining a new team, are addressed. Additional evidence which is consistent with shirking behavior shows that shirking occurs on offense, not defense, and for position players, not pitchers.
Post-collisional crustal thickening and plateau uplift of southern Tibet: Insights from Cenozoic magmatism in the Wuyu area of the eastern Lhasa block
Authors: Hao Lu-Lu , Wang Qiang , Kerr Andrew C. , Yang Jin-Hui , Ma Lin , Qi Yue , Wang Jun , Ou Quan
Published: December 2020

The nature and timing of post-collisional crustal thickening and its link to surface uplift in the eastern Lhasa block of the southern Tibetan plateau remain controversial. Here we report on Cenozoic magmatism in the Wuyu area of the eastern Lhasa block. The Eocene (ca. 46 Ma) trachyandesites and trachydacites show slight fractionation of rare earth elements (REE), slightly negative Eu and Sr anomalies, and relatively homogeneous Sr-Nd and zircon Hf isotopes (87Sr/86Sr(i) = 0.7050–0.7063, εNd(t) = −0.92 to −0.03, εHf(t) = +2.6 to +4.8). Previous studies have suggested Neo-Tethys oceanic slab break-off at 50–45 Ma; thus, the Wuyu Eocene magmatism could represent a magmatic response to this slab break-off and originate from relatively juvenile Lhasa crust. The Miocene (ca. 15–12 Ma) dacites and rhyolites have adakitic affinities, e.g., high Sr (average 588 ppm), Sr/Y (29–136), and La/Yb (30–76) values, low Y (4–12 ppm) and Yb (0.4–0.9 ppm) contents, and variable Sr-Nd and zircon Hf isotopes (87Sr/86Sr(i) = 0.7064–0.7142, εNd(t) = −11.7 to −3.7, εHf(t) = −3.2 to +4.5). Their more enriched Sr-Nd-Hf isotopes relative to the Eocene lavas indicate that they should be derived from mixed Lhasa lower crust comprising juvenile crust, ultrapotassic rocks, and probably Indian lower crust-derived rocks. This study has also revealed the transformation from Eocene juvenile and thin crust with a thickness of <40 km to Miocene mixed and thickened crust with a thickness of >50 km. Combined with published tectonic data, we suggest that both lithospheric shortening and magma underplating contributed to eastern Lhasa block post-collisional crustal thickening. Given the spatial-temporal distribution of eastern Lhasa block magmatism and regional geology, we invoke a post-collisional tectonic model of steep subduction of the Indian plate and subsequent westward-propagating plate break-off beneath the eastern Lhasa block, which caused the surface uplift.
Mixing of brine with oil triggered sphalerite deposition at Pine Point, Northwest Territories, Canada
Authors: Szmihelsky Marko , Steele-MacInnis Matthew , Bain Wyatt M. , Falck Hendrik , Adair Robin , Campbell Brandon , Dufrane S. Andrew , Went Ashley , Corlett Hilary J.
Published: December 2020

Hydrocarbons are commonly invoked as triggers for the precipitation of sphalerite in carbonate-hosted Pb-Zn deposits, but direct evidence for the presence of petroleum during sulfide mineralization is rarely documented. Here, we report evidence of fluid mixing between basinal brines and oil during deposition of coarse sphalerite at a classic carbonate-hosted Pb-Zn district, Pine Point, Northwest Territories, Canada. The brines contain high concentrations of Pb, detectable aqueous sulfate, and hydrocarbons that attest to chemical interaction with oil. The oil inclusions in sphalerite contain much less Pb relative to the brines and no evident H2S, suggesting that the principal role of hydrocarbons was as a reductant. Mixing of brine with oil enabled the conversion of aqueous sulfate to sulfide, and thereby triggered sphalerite deposition.
Fluid compositions reveal fluid nature, metal deposition mechanisms, and mineralization potential: An example at the Haobugao Zn-Pb skarn, China
Authors: Shu Qihai , Chang Zhaoshan , Mavrogenes John
Published: December 2020

Fluid inclusion compositions obtained from laser ablation–inductively coupled plasma–mass spectrometry at the Haobugao Zn-Pb skarn in northeastern China provide constraints on fluid origin, evolution, and metal deposition mechanisms and an example of evaluating mineralization potential. Metal concentrations in the prograde fluids were high (up to 1.4 wt% Zn and 1.8 wt% Pb) but remained in solution, likely due to the high temperatures (440–575 °C) and salinities (35.4–45.3 wt% NaCl equivalent). Absolute concentrations of elements (e.g., Rb and Na) and mass ratios (e.g., Zn/Na and K/Na) reveal that the early, prograde fluids were magmatic, consistent with the oxygen isotope composition of fluids (δ18OH2O = 5.5‰–8.5‰). Later mixing with a meteoric fluid caused dilution and Zn-Pb deposition, as revealed by lowered element concentrations and Pb/(Na + K) and Zn/(Na + K) ratios in the sulfide-stage fluid inclusions. Elevated Ca/K ratios in sphalerite-hosted inclusions indicate fluid-carbonate reactions that buffered fluid pH, also facilitating Zn-Pb precipitation. Although cassiterite and molybdenite occur locally at Haobugao, mass balance calculation shows low metal endowment (maximum 2900 t Sn and 2200 t Mo) of the system. Furthermore, the generally unchanged Sn/(Na + K) and Mo/(Na + K) ratios from pre- to late-mineralization fluids suggest that the fluids were never saturated in Sn and Mo. Therefore, finding much Sn or Mo at Haobugao is unlikely. This demonstrates a potential tool for evaluating the metal endowment of a mineral prospect, which may guide exploration.
Benign thyroid swelling presenting as Horner’s syndrome
Authors: Shaji Sherin K , Chan Jacquline , Hari Churunal
Published: December 2020

Horner’s syndrome is a rare neurological condition seen in association with the disruption in the sympathetic nerve supply. Thyroid swelling is a common condition but rarely causes cervical sympathetic chain compression. We describe a case of a 54-year-old man who presented with Horner’s syndrome secondary to a benign thyroid nodule with pressure effect on the sympathetic chain. An association between thyroid pathologies and Horner’s syndrome has been mentioned previously, however, to our knowledge, this is the first case of Horner’s syndrome being the initial presentation for an underlying benign thyroid swelling.
Neglected woman with hyperemesis gravidarum leading to Wernicke encephalopathy
Authors: Dasari Papa , Priyadarshini Smitha
Published: December 2020

A teenage primigravida at 13 weeks of gestation presented with hyperemesis gravidarum of 45 days and a history of giddiness and inability to walk due to involuntary movements of limbs and eyes since 2 days. She was treated with intravenous fluids, thiamine and antiemetics. MRI brain showed hyperintensities in bilateral dorsomedial thalami, periaqueductal grey matter in T2-weighted and FLAIR images. A diagnosis of Wernicke encephalopathy was made and she was managed in intensive care unit and received injection thiamine as per the guidelines and her weakness and ataxia improved over 3 weeks and she was discharged at 17 weeks of pregnancy in good state of health.
Strategies for improving the management of immune-related adverse events
Authors: Naing Aung , Hajjar Joud , Gulley James L , Atkins Michael B , Ciliberto Gennaro , Meric-Bernstam Funda , Hwu Patrick
Published: December 2020

With the advent of immunotherapeutic agents, durable and dramatic responses have been observed in several hard-to-treat malignancies, outlining a roadmap to conquering cancer. Immune checkpoint inhibitors (ICPi) are a class of immunotherapeutic agents that attack the tumor cells by reinvigorating the suppressed immune system. However, the unbridled T-cell activity disrupts the immune homeostasis and induces a unique spectrum of side effects called immune-related adverse events (irAEs) in a significant proportion of patients. These irAEs are distinct from the side effects produced by traditional chemotherapeutic agents. Although majority of irAEs are manageable with corticosteroids and other immunosuppressive agents, life-threatening and fatal events have been reported. In the absence of predictive biomarkers to identify patients at risk for irAEs and standardized approach to detect, report, and treat irAEs, management of irAEs has been challenging to the patients, caregivers and the healthcare providers alike. With increasing use of ICPis for treatment of various cancers, the incidence of irAEs will undoubtedly increase. There is a compelling need to develop measures to effectively manage irAEs, both in the community settings and in cancer centers alike. To this end, in this paper, we propose several strategies, such as providing patient education, harmonizing irAE management guidelines, standardizing reporting of irAEs, optimizing the choice of immunosuppressive agents, conducting preclinical, clinical and translational studies to better understand irAEs, including high-risk patients, incorporating diagnostic tools to personalize irAE management using wireless technology and digital health, providing a platform to hear the missing patient’s voice, and sharing evolving data to improve the management of irAEs.
Lead toxicity in a suckler calf
Authors: George Anna
Published: December 2020

A three‐month‐old male suckler calf presented with a history of acute recumbency, anorexia, hypersalivation and subsequent central blindness. The calf was in a group at grass near an old quarry, so concerns were raised regarding primary lead toxicity and supportive treatment implemented. Unfortunately, this treatment proved unsuccessful and the calf passed away. A damaged lead‐acid car battery was later found in the field and postmortem testing of kidney tissue yielded lead levels of 22 mg/kg, with <0.1 mg/g being the expected normal level due to background exposure. Levels this high warranted further investigation to ensure the safety of food products from the herd entering the food chain, in conjunction with animal health and welfare.
Bovine lactoferrin and lactoferrin peptides affect endometrial and cervical cancer cell lines
Authors: Ramírez-Sánchez Diana A. , Arredondo-Beltrán Izamar G. , Canizalez-Roman Adrián , Flores-Villaseñor Héctor , Nazmi Kamran , Bolscher Jan G.M. , León-Sicairos Nidia
Published: December 2020

Cervical, uterine, and ovarian cancers are the most common malignancies of the female genital tract worldwide. Despite advances in prevention, early diagnosis, effective screening, and treatment programs, mortality remains high. Consequently, it is important to search for new treatments. The activity of bovine lactoferrin (bLF) and LF peptides against several types of cancer has been studied; however, only a few studies report the effect of bLF and LF peptides against cervical and endometrial cancers. In this study, we explored the effect of bLF as well as LF chimera and its constituent peptides LFcin17–30 and LFampin265–284 on the viability of cervical (HeLa, SiHa) and endometrial (KLE, HEC-1A) cancer cell lines. Cell proliferation was quantified with an MTT assay, cell morphological changes and damage were determined by Giemsa and phalloidin-TRITC and DAPI staining, and apoptotic and necrotic cells were identified by Alexa Fluor® 488 Annexin V and propidium iodide staining. Additionally, the effect of combinations of bLF and LF peptides with cisplatin was assessed. bLF and LF peptides inhibited the proliferation of uterine cancer cells and caused cellular morphological changes and damage to cell monolayers. bLF induced apoptosis, LFcin17–30 and LFampin265–284 induced apoptosis and necrosis, and LF chimera induced necrosis. Additionally, bLF and LF chimera showed an additive interaction with cisplatin against uterine cancer cells.
Interaction of massless minimally coupled scalar field with spinor field in de Sitter universe
Authors: Ahmadi Y.
Published: December 2020

The interaction of massless minimally coupled scalar field and spinor field [Formula: see text] is investigated and the behavior of interaction and scattering matrix in Minkowski limit is studied. It is seen that the massless minimally coupled scalar field operator, the interaction Lagrangian and the scattering matrix become zero. Also, the incoming and outgoing spinor fields, which in de Sitter spacetime are different and are interacted with massless minimally coupled scalar field, in null curvature limit are the same and no interaction seen. In other words, the massless minimally coupled scalar field is dependent on curvature and can be considered as a part of a gravitational field.
Uniform convexity of general direct sums and interpolation spaces
Authors: Markowicz Joanna , Prus Stanisław
Published: December 2020

An estimate for the modulus of convexity and characteristic of convexity of a general direct sum of Banach spaces is established. Using direct sums, we construct a space with given characteristic of convexity and the value of the modulus of convexity at 2. A result on uniform convexity of spaces obtained with the general discrete interpolation method is proved.
Investor sentiment and the risk-return tradeoff
Authors: Amiri Mohamed Marouen , Naoui Kamel , Derbali Abdelkader , Sassi Mounir Ben
Published: December 2020

The purpose of this paper is to investigate the risk-return tradeoff allowing for the presence of noise traders, i.e., a subset of investors who either base their trading strategies on sentiment or hold unjustified optimistic/pessimistic views regarding market prospects. We measure noise traders’ sentiment relying on two sets of indices, namely the Baker and Wurgler sentiment index and the Michigan Consumer Confidence Index, in the US stock market. Under the assumption of the presence of noise traders’ sentiment, the risk-return tradeoff is tested through two sets of models: Merton’s Intertemporal CAPM and the GARCH-in-mean model. First, we find that the relationship between risk and return allowing for the presence of noise trader risk as measured by the Baker and Wurgler sentiment index is positive and statistically significant when tested through Merton’s Intertemporal CAPM. Second, the risk-return tradeoff tested through GARCH-in-mean models augmented by noise traders’ risk as measured through survey-based measures of sentiment establishes no clear evidence for a significant mean–variance relationship. Overall, we confirm Merton’s (1973) hypothesis that the more risk an investor bears, the greater his expected returns. This paper contributes to the asset pricing literature by trying to shed some light on the risk-return tradeoff from the standpoint of behavioral finance.
Electrochemical Performance of Co3O4 Anode Material with Conductive Binder
Authors: Kamenskii Mikhail A. , Vypritskaya Angelina I. , Eliseeva Svetlana N. , Kondratiev Veniamin V.
Published: December 2020

A water-soluble conductive binder consisting of poly-3,4-ethylenedioxythiophene:polysterne sulfonate and carboxymethyl cellulose was proposed for conversion Co3O4 anode material. This type of electrode shows ultrahigh specific capacity value and brilliant C-rate capability in comparison with Co3O4 electrode with poly(acrylic acid) and carboxymethyl cellulose was used. It also demonstrates better stability during continuous cycling at 0.2 C. Long-term cycling voltammetry measurements show that using of conducting polymer as binder component lead to superior stability of the Co3O4 electrodes.
Improving Electrochemical Properties of LiMn2O4/LiNi0.5Mn1.5O4 Core/Shell Composites
Authors: Potapenko Anna V. , Kirillov Sviatoslav A. , Kravets Yuliya
Published: December 2020

The electrochemical properties of LiMn2O4 surface modified with LiNi0.5Mn1.5O4 at different current densities are presented. The electrode with a maximum percentage of covering (14% of LiNi0.5Mn1.5O4) can endure higher current loads compared with the sample consisting 7% of surface layer. The capacity values for these samples at 45° and 30°C are 22 and 31 mAh∙g-1, respectively. This means that the proposed approach can be an effective tool for obtaining electrode materials for high-rate applications.
Preparation and Electrochemical Characterization of Gel Polymer Electrolyte Based on Tetraalkylammonium Tetrafluoroborate for Electrochemical Power Sources
Authors: Veselkova Iuliia , Sedlarikova Marie
Published: December 2020

Gel polymer electrolytes based on tetraalkylammonium tetrafluoroborate (TEA BF4) were prepared and their electrochemical properties were studied. The impedance spectroscopy method was used to calculate electrical conductivity of electrolytes in different temperatures. Linear sweep voltammetry studies were performed to determine electrochemical stability of gel polymer electrolytes.
Gel Polymer Electrolyte Based on Methyl Methacrylate and Ethyl Methacrylate for Lithium-Ion Batteries
Authors: Peterova Sona , Veselkova Iuliia , Kazda Tomas , Sedlarikova Marie
Published: December 2020

This article deals with gel polymer electrolytes (GPEs) composed of methacrylate-based copolymers. The experiment is based on the preparation of GPE with copolymers, measurement of their electrochemical properties, and following measurements with negative electrode LTO (Li4Ti5O12) and positive electrode NMC (LiNi0.33Mn0.33Co0.33O2). The functionality of electrolyte was verified by cyclic voltammetry and measurement of capacity.
Melanin as Semiconductor with Polymer Structure is Effective Modifier for Electrodes of High-Energy Li-Ion Batteries
Authors: Shembel Elena , Kyrychenko Volodymyr , Maksyuta Irina , Redko Volodymyr , Zaderey Nellya
Published: December 2020

Melanin is a biological organic polymer and has semiconductor properties. The structure of organic semiconductors, including melanin, determines the mechanism of their conductivity, electrical, and catalytic properties. Research the properties of melanin, which are synthesized on the basis of innovative technologies developed by Sunoil-Agro, confirms the innovating prospects for using melanin with goal to modify electrodes of Li-ion batteries. Results of investigation and developed the method modification the cathode materials of Li-ion batteries are presented in this article. The goal is to increasing the energy and power characteristics of LiMn2O4-based cathodes as a result of their modification with melanin.
Intercalation Properties of Expanded Graphite Electrode in Lithium-Ion Battery
Authors: Libich Jiri , Sedlarikova Marie , Maca Josef , Čudek Pavel , Fíbek Michal , Chekannikov Andrey , Fafilek Guenter
Published: December 2020

The energy storage become one of most important a strategic area in context of sustainable development of human society. With last two decades, the electrochemical energy storage devices (batteries), got crucial role. The current trend led by electromobility, renewable energy resources set new level of requirements on battery parameters. Since 1991 when the first commercial lithium-ion battery was produced, this battery technology developed to the most advanced battery technology on the market. Lithium-ion batteries found application in wide range of devices from small portable electronic devices, via electric vehicles up to huge stationary energy storage systems. Important parameter of the battery it is the rate capability parameter. The current generation which occurs in the battery during charging-discharging cycle is directly proportional to rate of reactions. And the reaction rate depends on diffusion rate. In this work the diffusion rate expressed by chemical diffusion coefficient is measured and evaluated.
New Hybrid Phospho-Siloxane Membranes for H2/O2 Fuel Cells
Authors: Mika Martin , Ören Doğukan Ilbey , Michal Jakub
Published: December 2020

Currently, the low operating temperatures of commercial proton conducting polymer membranes and their humidity requirements for achieving sufficiently high proton conductivity add high complexity to fuel cell systems, which impacts their cost and durability. In our research, we focused on the development of new cost-effective polymer nanocomposite membranes with better medium-temperature performance.
Reduced Graphene Oxide Composited with Ni-MOF and PANI Applied as Electrodes for Supercapacitor
Authors: Le Quoc Bao , Fei Haojie , Bubulinca Constantin , Ngwabebhoh Fahanwi Asabuwa , Kazantseva Natalia E. , Saha Petr
Published: December 2020

The different composites made of rGO, Ni-MOF, and PANI were synthesized via the hydrothermal method and used for the fabrication of electrodes for supercapacitors. The structure and morphology of composites obtained were characterized via SEM, XRD, and FTIR. The electrochemical properties of electrodes were studied using CV and galvanostatic charge/discharge methods, as well as by EIS. The results obtained demonstrated that the incorporation of rGO, Ni-MOF, and PANI significantly increase the specific capacitance of electrodes. It can be explained by the formation of a better specific surface area with a branched porous structure that enhances the contact between electrolyte ions with the electrode materials. The specific capacitance of rGO/Ni-MOF/PANI in 1 M H2SO4 electrolyte is 195.14 F/g at 0.2 A/g charge-discharge and the average capacitance retention remained 79.78% after 5,000 cycles at current density 1 A/g.
Influence of Temperature on Impedance Changes of Lead-Acid Battery Cell
Authors: Křivík Petr , Baca Petr , Kazelle Jiri
Published: December 2020

The paper deals with the influence of temperature on the cell impedance parameters during discharge and charge of the lead-acid battery cell. Nyquist diagrams for different temperatures were compared. Impedance modulus was measured for different frequencies by the PEIS method.
Synergistic Effect of Nanotechnology and Optimized Industrial Manufacturing Process for Lead Electrodes Enhances the Performance of Lead-Acid Batteries
Authors: Bulat Anatoly , Shembel Elena , Polishchuk Yuliya , Blyuss Boris , Redko Volodymyr , Nefedov Vladimir , Zaderey Nellya , Pustovalov Yury
Published: December 2020

The results of research and development, which are presented in this article, confirm the prospects for the use of modifying additives based on Nano dispersed carbon-nature additives in the electrodes of lead-acid batteries. The energy, power, and stability parameters during cycling the electrodes of the lead-acid battery are increased. The developed method of modification is technological, easy to operate, does not require the use of scarce materials, and there are significant production costs for implementation in production. The use of this innovative approach to modifying the technology for manufacturing electrodes of lead-acid batteries solves significant problems that appear for both the positive and negative electrodes.
Polymer Structure of Sulfur Ensures Low Self-Discharge of Li-S Primary and Secondary Batteries/Synergistic Effect of Sulfur Structure and Design of Sulfur Electrode
Authors: Polishchuk Yuliya , Shembel Elena , Strakova Fedorkova Andrea
Published: December 2020

The dynamics of change in the impedance spectra and electrochemical parameters of Li-S rechargeable batteries with non-aqueous electrolyte during a) storage after the cell assembly and b) during the following cycling have been presented. The development of the innovating technology and design of the electrode based on polymer sulfur results in a dramatic increas in the properties of Li-S batteries with 0.7 M bis(triuoromethanesulfone)imide (LiIm), 0.25 M LiNO3, DME: DOL (2:1) as an electrolyte.
Enhancing of Electrochemical Characteristics of Li-S System by Means of Optimization of Sulfur Electrode and Electrolyte Composition
Authors: Globa Nataliya I. , Sirosh Vitalii A. , Kirillov Sviatoslav A.
Published: December 2020

The article discusses the influence of technological parameters of sulfur electrodes and the concentration composition of the salt-solvation electrolytes TEGDME–LiTFSI on the specific characteristics of Li-S cells obtained under galvanostatic cycling conditions. The dependences of the specific capacity on the composition of the cathode, the charge-discharge current density, as well as capacity retention upon storage are discussed.
Innovating Technology Generates Solid Electrolyte with High Ionic Conductivity for Lithium Batteries
Authors: Amelina Aleksandra , Shembel Elena , Strakova Fedorkova Andrea , Redko Volodymyr
Published: December 2020

Technology of increasing the ionic conductivity of a solid electrolyte which is based on lithium penta aluminate has been developed The positive effect of the surface treatment of a solid electrolyte with melts of lithium salts on its ionic conductivity has been investigated and confirmed. Non-destructive non-contact electromagnetic method for testing modified solid electrolyte has been used.
Electrochemical Behavior of Composites of Poly-3,4-Ethylenedioxythiophene with ManGanese Oxide and Tungsten Oxide: Similarities and Differences
Authors: Holze Rudolf , Kondratiev V. V.
Published: December 2020

The current response in cyclic voltammogranms of MnO2, WO3, and their composites with poly-3,4-ethylenedioxythiophene have been analyzed with regard to classification of the materials as being battery-electrode like or pseudocapacitive taking into account the current state of debate on this topic. Reasons for the observed differences and discrepancies from reported claims and suggestions are critically examined.
Real-Measured Properties of Photovoltaic Modules Manufactured in 2018-2019
Authors: Vanek Jiri , Maule Petr
Published: December 2020

First part of the work deals with the comparison of measured parameters of photovoltaic modules of various actual manufacturers with the data given in the catalog sheets. These data are compared with data obtained in the past from a similar measurement with a focus on comparing these data with respect to the continent where these modules were manufactured. Second part of the work is focused on analyzing of PV modules parameters with different technology and manufacturers in dependence to light intensity.
Iron-Based Materials for Biodegradable Implants Prepared by Powder Metallurgy
Authors: Sedlarikova Marie , Mika Martin , Hrabovsky Jan , Tkacova Tereza , Fafilek Guenter , Cudek Pavel
Published: December 2020

Preparation of metal components by a modified powder technology was checked. Iron powder is used for manufacturing of an object of arbitrary form. Its final treatment occurs in nitrogen at 1120°C.
Possibilities of the Utilization of Nitriding on Case-Hardening Steels
Authors: Prochazka Jiri , Pokorny Zdenek , Nguyen Chien Huu
Published: December 2020

This paper studies the possibility of using plasma nitriding for treating case-hardening steels. For the experiment, the case-hardening steels equivalent 1.7131 (i.e., CSN 41 4220) and equivalent 1.5752 (i.e., CSN 41 6426), used in manufacturing of exposed parts of military and special vehicles as well as in parts of weapons, were selected. The verification of chemical composition was performed by the optical emission spectrometer Tasman Q4 Bruker. For observations of the microstructure and assessment of compound layers, the instrument Olympus DSX500i was used. In accordance with ISO 18203:2016(E), the depth of diffusion layers was evaluated from profiles of microhardness measured by the automated microhardness tester LM247 AT LECO. The results of the experiments show benefits of applying plasma nitriding upon the selected case-hardening steels.
Simple Method of Graphene Quantum Dots Preparation from Partially Unzipped Multi-Walled Carbon Nanotubes
Authors: Danilov Michail O , Fomanyuk Sergii S , Dovbeshko Galina I , Gnatyuk Olena P , Rusetskii Igor A , Kolbasov Gennadii Ya , Yaremchuk Galina G
Published: December 2020

A method for producing graphene quantum dots (GQDs) by ultrasonic grinding of e1lectrochemically obtained partially unzipped multi-walled carbon nanotubes is proposed. As a result, photoluminescent GQDs with a blue glow have been obtained from partially unzipped multi-walled carbon nanotubes processed two hours by ultrasonic grinding (UZ-CNTs). Various physicochemical methods including photoluminescence spectroscopy have been used to study the electrochemically synthesized UZ-CNTs GQD. After ultrasonic grinding of electrochemically synthesized UZ-CNTs the GQDs were obtained as a result of the exfoliation from the stress-bent MWCNTs walls one- or two-layer cup-shaped graphene nanoparticles 1.5-3 nm in size. The obtained GQDs are promising materials as a new type of catalyst carriers for oxygen electrodes of fuel cells.
Tribological Properties of DLC Coating for Parts of Weapons
Authors: Studeny Zbynek , Pokorny Zdenek , Dobrocky David , Joska Zdenek , Prochazka Jiri
Published: December 2020

The article deals with the surface material, which is suitable to produce parts of weapons. These parts of weapons are exposed to external influences during their service life, which reduce their service life. There are both external and internal surfaces of the functional parts of weapons. These surfaces are particularly exposed to increased pressure and temperature. The environments, in which they work, are very often aggressive and extreme. There is an increased risk of wear and corrosion on the external and internal surfaces of such components. Suitable surface treatment can increase the surface hardness, abrasion resistance, corrosion resistance, etc. of surface weapon parts. This article comprehensively evaluates the tribological properties of the DLC coating on a steel substrate and on an aluminum alloy substrate. It is important to know the properties of the coating on these substrates when designing weapon components. The use of lighter materials reduces the overall complexity of each soldier's combat mission.
Velocity and Temperature Profile Analyzes in Supersonic Flow in the Experimental System
Authors: Šabacká Pavla , Maxa Jiří , Vyroubal Petr
Published: December 2020

This article deals with the preparation of the experimental chamber on which, among other things, stagnation and static temperature will be measured. The results obtained from the measurements will be compared with the results of mathematical-physics analyzes of the Ansys Fluent system. Analyzes of the expected stagnation temperatures at the tip of the probes were performed with respect to the course of the Mach number from the aperture.
Approximation of Battery Transfer Function Using Neural Network
Authors: Cipin Radoslav , Toman Marek , Procházka Petr , Pazdera Ivo , Miklas Jan
Published: December 2020

This paper deals with a mathematical description of an alkaline battery impedance dependence on frequency. This mathematical description is done in two different ways. In the first case, a general fractional transfer function is used and in the second case an artificial neural network is used. Both approaches are discussed and compared with real measurement.
Portable DC Supply Powered from Battery
Authors: Folprecht Martin , Procházka Petr , Červinka Dalibor
Published: December 2020

This contribution refers about a design and development of a regulated DC-DC converter with pulse transformer, which is powered from a battery or an on-board car network. This converter with adjustable output voltage and current value can supply many appliances. The design of pulse transformer, secondary rectifier, output filter, switching transistors, and control circuits is included.
Analysis of a Phase Change Material for Thermal Management of a Lithium-Ion Battery
Authors: Madani Seyed Saeed
Published: December 2020

A passive thermal management system for a lithium-ion battery by employing phase change material as the heat transfer source to manage lithium-ion battery temperature increase was developed. Lithium-ion battery temperature rise is caused by electrochemical reactions. If the lithium-ion battery temperature is not properly controlled, then it will cause a shortening of its lifespan, faster capacity reduction, or even in severe cases, might cause lithium-ion battery explosion. For commercial big-energy applications, a proper lithium-ion battery thermal management allows us to overcome problems related to heat production and improves significantly the performance of the lithium-ion battery. In this investigation behavior of a phase change material was analyzed. The phase change material was used as a medium for the thermal management of a lithium-ion battery cell. A three dimensional numerical model for the lithium-ion battery thermal management system according to phase change material was accomplished by using Ansys Fluent.
Experimental Study of the Heat Generation of a Lithium-Ion Battery
Authors: Madani Seyed Saeed
Published: December 2020

This investigation exhibits an experimental study on the heat flux quantification for a lithium-ion battery at different discharge and charge rates. An isothermal battery calorimeter was used for a lithium-ion battery thermal analysis. Experimental analyses of the thermal transmission of lithium-ion batteries are accomplished under different discharge and charge rates to produce more information about the heat generation of the lithium-ion battery. The objective of the existent investigation is to assess the generated heat inside a lithium-ion battery cell throughout several discharging and charging cycles. In this study, the temperature distribution is exhibited for a lithium-ion battery at dissimilar working conditions. It was concluded that the difference between the maximum temperatures measured at the lower part of the lithium-ion battery is comparatively small compared with the upper part of the lithium-ion battery surface and its central part.
Thermal Abuse of Lithium Ion Battery Investigated by Simulation
Authors: Vyroubal Petr , Kazda Tomas , Mačák Martin
Published: December 2020

Professional testing of thermal safety of batteries is relatively costly and at the same time quite dangerous. Using computer simulation for a battery thermal accident, on the other hand, is much cheaper and safer. But does it achieve sufficient accuracy?
Transient Simulation of Scanning Electrochemical Microscope
Authors: Mačák Martin , Vyroubal Petr
Published: December 2020

The presented article describes a transient numerical model of a scanning electrochemical microscope used for investigating topography and conductivity of various surfaces. The custom numerical model, implemented into Ansys Fluent software, is based on Poisson-Nernst-Planck equations coupled with electrochemical reactions. Presented simulations investigate the influence of irregularities on the scanned surface. Simulations were carried out for different cases with arrangement of conducting and insulating surfaces.
Innovative Non-Destructive Electromagnetic Method for Testing and Investigation: The Basis of New Technologies for Production High-Energy Batteries
Authors: Redko Volodymyr , Shembel Elena , Khandetskyy Volodymyr , Strakova Fedorkova Andrea , Pastushkin Tymofiy , Novak Peter , Redko Alexander
Published: December 2020

The efficiency of an electrochemical power source, to a great degree, depends on the internal resistance of the system. This internal resistance includes interface resistance between current collector and active electrode mass, solid electrolyte and electrode, and other systems. The developed method and device enable non-destructive, non-contact evaluation of the interface resistance. Results enable the prediction and optimization of electrochemical power sources properties, especially their power.