244 results on '"Petrů M"'
Search Results
2. Experimental and theoretical assessment of crack kinking in marble stones in the presence of a V-notch under mode I loading
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Bahrami, B., Bahadori, A., Petru, M., Nejati, M., and Ayatollahi, M.R.
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- 2022
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3. Composite Production and Industrial Robot Trajectory Calculation
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Martinec, T., Mlýnek, J., Petrů, M., Ceccarelli, Marco, Series editor, Beran, Jaroslav, editor, Bílek, Martin, editor, and Žabka, Petr, editor
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- 2017
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4. Research of New Composites for Lightweight Construction with Low Impact on the Environment
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Petrů, M., Lepsik, P., Novák, Ondřej, Dynybyl, Vojtěch, editor, Berka, Ondrej, editor, Petr, Karel, editor, Lopot, František, editor, and Dub, Martin, editor
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- 2016
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5. Reduce of Head Injuries During Whiplash Using TRIZ Methodology
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Lepšík, P., Petrů, M., Novak, O., Ševĉik, Ladislav, editor, Lepšík, Petr, editor, Petrů, Michal, editor, Mašín, Ivan, editor, and Martonka, Rudolf, editor
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- 2014
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6. Dynamic Analysis of Lifting Platform Construction for Car Relocation
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Petrů, M., Ševčík, L., Mašín, I., Lepšík, P., Lufinka, A., Novak, O., Ševĉik, Ladislav, editor, Lepšík, Petr, editor, Petrů, Michal, editor, Mašín, Ivan, editor, and Martonka, Rudolf, editor
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- 2014
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7. Innovation of Car Seat Construction Using TRIZ-Based Tool: Function-Oriented Search
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Lepšík, P., Petrů, M., Novak, O., Ševĉik, Ladislav, editor, Lepšík, Petr, editor, Petrů, Michal, editor, Mašín, Ivan, editor, and Martonka, Rudolf, editor
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- 2014
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8. On the dynamic response of viscoelastic functionally graded porous plates under various hybrid loadings
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Alavi, S. Karen, primary, Ayatollahi, Majid R., additional, Petrů, M., additional, and Koloor, S.S.R., additional
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- 2022
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9. Distribution Pattern of the Aquatic Fauna of the Balkan Peninsula
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Bănărescu, Petru M., Griffiths, Huw I., editor, Kryštufek, Boris, editor, and Reed, Jane M., editor
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- 2004
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10. Displacement rate effects on mixed-mode I/II delamination of laminated carbon/epoxy composites
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Low, K, Johar, M, Sung, Aun Naa, Nasir, M, Koloor, S, Petrů, M, Israr, H, Wong, K, Low, K, Johar, M, Sung, Aun Naa, Nasir, M, Koloor, S, Petrů, M, Israr, H, and Wong, K
- Abstract
Mixed-mode delamination is one of the common failures of composites which has not been studied under low-impact loading. This paper studies the influence of displacement rate on mixed-mode I/II delamination of unidirectional carbon/epoxy composites. Single leg bending test is performed at displacement rates of 1, 10, 100, and 500 mm/min. Experimental results reveal that the mixed-mode I/II fracture toughness is invariant with the displacement rate. In addition, scanning electron micrographs shows that shear cusps are more obvious at 1, 10, and 100 mm/min. At 500 mm/min, significant matrix debris is noticed. Furthermore, the proposed three-dimensional rate-dependent fracture criterion is found to well predict the fracture toughness. Numerical simulation using cohesive zone model suggests that the lower numerical peak load is due to lower damage dissipated energy. In addition, the theoretical and numerical traction-separation responses show significant differences, which is also reflected in the numerical phase angle. This implies that the local mixed-mode ratio is not constant throughout the simulation process.
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- 2022
11. Damage characterization of dental nanocomposite adhesive in orthodontic treatment applications
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Karimzadeh, A, primary, Koloor, S S R, additional, Petrů, M, additional, Ayatollahi, MR, additional, and Yahya, MY, additional
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- 2022
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12. Composite Production and Industrial Robot Trajectory Calculation
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Martinec, T., primary, Mlýnek, J., additional, and Petrů, M., additional
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- 2016
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13. ARISGAN: Extreme super-resolution of arctic surface imagery using generative adversarial networks
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Christian Au, Michel Tsamados, Petru Manescu, and So Takao
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super-resolution ,remote sensing ,computer vision ,synthetic satellite imagery ,arctic environment ,sea ice ,Geophysics. Cosmic physics ,QC801-809 ,Meteorology. Climatology ,QC851-999 - Abstract
Introduction: This research explores the application of generative artificial intelligence, specifically the novel ARISGAN framework, for generating high-resolution synthetic satellite imagery in the challenging arctic environment. Realistic and high-resolution surface imagery in the Arctic is crucial for applications ranging from satellite retrieval systems to the wellbeing and safety of Inuit populations relying on detailed surface observations.Methods: The ARISGAN framework was designed by combining dense block, multireceptive field, and Pix2Pix architecture. This innovative combination aims to address the need for high-quality imagery and improve upon existing state-of-the-art models. Various tasks and metrics were employed to evaluate the performance of ARISGAN, with particular attention to land-based and sea ice-based imagery.Results: The results demonstrate that the ARISGAN framework surpasses existing state-of-the-art models across diverse tasks and metrics. Specifically, land-based imagery super-resolution exhibits superior metrics compared to sea ice-based imagery when evaluated across multiple models. These findings confirm the ARISGAN framework’s effectiveness in generating perceptually valid high-resolution arctic surface imagery.Discussion: This study contributes to the advancement of Earth Observation in polar regions by introducing a framework that combines advanced image processing techniques with a well-designed architecture. The ARISGAN framework’s ability to outperform existing models underscores its potential. Identified limitations include challenges in temporal synchronicity, multi-spectral image analysis, preprocessing, and quality metrics. The discussion also highlights potential avenues for future research, encouraging further refinement of the ARISGAN framework to enhance the quality and availability of high-resolution satellite imagery in the Arctic.
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- 2024
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14. The contribution of plyometric exercises assisted by sensory technology on vertical jump parameters in U15 female volleyball players
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Liviu Grădinaru, Petru Mergheș, and Mihaela Oravițan
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volleyball ,plyometrics ,sensory technology ,vertical jump ,Special aspects of education ,LC8-6691 ,Sports ,GV557-1198.995 - Abstract
Background and Study Aim. Volleyball requires high vertical jump skills for crucial actions like attacking and blocking, making jump training a focus for players, especially in youth categories. The main goal of the study was to highlight (with some specific data) the strengths and weaknesses of integrating sensory technology into the physical training program, during the entire competitive period. Material and Methods. The study included both an experimental and a control group, each consisting of 16 female athletes from the volleyball section of the Cetate Sports High School in Deva. During the competitive season of 2022/2023, both groups underwent daily training sessions from Monday to Saturday, totaling 120 minutes per day. The BlazePod Flash Reflex Training system was employed in this research. It integrates cognitive training to enhance thinking speed and clarity with physical exercises aimed at maximizing motor skills. Performance evaluations of the athletes utilized eight predefined tests from the OptoJump Next optical measuring system and the Myotest accelerometric system. To analyze the data, paired (dependent) sample t-tests were conducted to compare average parameters between matched samples. Repeated measures ANOVA was utilized to compare the average outcomes, ensuring the participants were consistent across the evaluated conditions. Results. The experimental group showed significant improvements in the height reached from the center of gravity and flight time for the following tests: Countermovement Jump, Countermovement Jump with Arm Swing, Squat Jump, Squat Jump with Arm Swing, and Drop Jump from 30 cm. All improvements reached statistical significance: p
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- 2024
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15. Fourth generation biofuel from genetically modified algal biomass: Challenges and future directions
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Shokravi, H, Shokravi, Z, Heidarrezaei, M, Ong, HC, Rahimian Koloor, SS, Petrů, M, Lau, WJ, and Ismail, AF
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Biofuels ,Microalgae ,Meteorology & Atmospheric Sciences ,Biomass ,Plants ,Genetic Engineering ,Environmental Sciences - Abstract
Genetic engineering applications in the field of biofuel are rapidly expanding due to their potential to boost biomass productivity while lowering its cost and enhancing its quality. Recently, fourth-generation biofuel (FGB), which is biofuel obtained from genetically modified (GM) algae biomass, has gained considerable attention from academic and industrial communities. However, replacing fossil resources with FGB is still beset with many challenges. Most notably, technical aspects of genetic modification operations need to be more fully articulated and elaborated. However, relatively little attention has been paid to GM algal biomass. There is a limited number of reviews on the progress and challenges faced in the algal genetics of FGB. Therefore, the present review aims to fill this gap in the literature by recapitulating the findings of recent studies and achievements on safe and efficient genetic manipulation in the production of FGB. Then, the essential issues and parameters related to genome editing in algal strains are highlighted. Finally, the main challenges to FGB pertaining to the diffusion risk and regulatory frameworks are addressed. This review concluded that the technical and biosafety aspects of FGB, as well as the complexity and diversity of the related regulations, legitimacy concerns, and health and environmental risks, are among the most important challenges that require a strong commitment at the national/international levels to reach a global consensus.
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- 2021
16. The development of value-added yogurt based on pumpkin peel powder as a bioactive powder
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Roxana Nicoleta Gavril (Rațu), Petru Marian Cârlescu, Ionut Dumitru Veleșcu, Vlad Nicolae Arsenoaia, Florina Stoica, Nicoleta Stănciuc, Iuliana Aprodu, Oana Emilia Constantin, and Gabriela Râpeanu
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Cucurbitaceae ,Pumpkin peel ,Phytochemicals ,Carotenoids ,Value added yogurt ,Agriculture (General) ,S1-972 ,Nutrition. Foods and food supply ,TX341-641 - Abstract
This study aimed to explore the utilization of pumpkin by-products as a bioactive powder in the development of value-added yogurt. Pumpkin peel resulting from food processing contains antioxidant components like phenolics, flavonoids, and carotenoids, compounds characterized by high bioactivity. This study investigated the potential of incorporating pumpkin peel powder (PPP) into yogurt to enhance its nutritional value and sensory attributes.Results indicated that the incorporation of PPP into yogurt resulted in improvements in nutritional composition, particularly in terms of β-carotene and bioactive compounds. Additionally, the addition of PPP positively influenced the textural properties of the yogurt. The sensory evaluation revealed that the incorporation of pumpkin peel had no negative impact on the overall acceptability of the yogurt, with some samples (YPP2) even exhibiting preferred sensory characteristics compared to the control. The utilization of PPP as a bioactive powder in yogurt presents a promising strategy for reducing food waste and creating innovative, value-added dairy products. The development of such products can not only contribute to sustainable food production but also provide consumers with more diverse food choices with enhanced characteristics.
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- 2024
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17. Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study
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R. Koloor, S. S., Karimzadeharani, A., Abdullah, M. R., Petrů, M., Yidris, N., Sapuan, S. M., Tamin, M. N., R. Koloor, S. S., Karimzadeharani, A., Abdullah, M. R., Petrů, M., Yidris, N., Sapuan, S. M., and Tamin, M. N.
- Abstract
The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures.
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- 2021
18. Limited view CT reconstruction and segmentation via constrained metric labeling
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Singh, Vikas, Mukherjee, Lopamudra, Dinu, Petru M., Xu, Jinhui, and Hoffmann, Kenneth R.
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- 2008
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19. Improving ‘lipid productivity’ in microalgae by bilateral enhancement of biomass and lipid contents: A review
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Shokravi, Z, Shokravi, H, Chyuan, OH, Lau, WJ, Koloor, SSR, Petrů, M, Ismail, AF, Shokravi, Z, Shokravi, H, Chyuan, OH, Lau, WJ, Koloor, SSR, Petrů, M, and Ismail, AF
- Abstract
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Microalgae have received widespread interest owing to their potential in biofuel production. However, economical microalgal biomass production is conditioned by enhancing the lipid accumulation without decreasing growth rate or by increasing both simultaneously. While extensive investigation has been performed on promoting the economic feasibility of microalgal-based biofuel production that aims to increase the productivity of microalgae species, only a handful of them deal with increasing lipid productivity (based on lipid contents and growth rate) in the feedstock production process. The purpose of this review is to provide an overview of the recent advances and novel approaches in promoting lipid productivity (depends on biomass and lipid contents) in feedstock production from strain selection to after-harvesting stages. The current study comprises two parts. In the first part, bilateral improving biomass/lipid production will be investigated in upstream measures, including strain selection, genetic engineering, and cultivation stages. In the second part, the enhancement of lipid productivity will be discussed in the downstream measure included in the harvesting and after-harvesting stages. An integrated approach involving the strategies for increasing lipid productivity in up-and down-stream measures can be a breakthrough approach that would promote the commercialization of market-driven microalgae-derived biofuel production.
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- 2020
20. Linear-Nonlinear Stiffness Responses of Carbon Fiber-Reinforced Polymer Composite Materials and Structures: A Numerical Study
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R. Koloor, S. S., primary, Karimzadeh, A., additional, Abdullah, M. R., additional, Petrů, M., additional, Yidris, N., additional, Sapuan, S. M., additional, and Tamin, M. N., additional
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- 2021
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21. HEADACHE, TEMPOROMANDIBULAR DISORDERS AND SELF-MEDICATION: FINDINGS FROM A LARGE SAMPLE QUESTIONNAIRE STUDY INVOLVING 1019 PARTICIPANTS
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Manuela Lalu, Marius Sorin Pop, Olivia Andreea Marcu, and Petru Mihancea
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temporomandibular disorders ,headache ,self-medication ,Dentistry ,RK1-715 - Abstract
The aim of this study was to assess the prevalence of temporomandibular disorders in patients suffering from headaches and the association of several types of headache in the same patient. Material and methods: We carried out a research based on the survey technique, using an online-managed questionnaire as tool. The questionnaire we used included elements as suggested by the International Headache Society (IHS) and was intended to identify both the headache form and the TMD specific symptomatology. The total number of respondents was 1019. Results: We were able to identify a close relation between headache and TMD. The data analysis shows an increased prevalence of headaches in women. The questionnaire revealed that a higher percentage of the respondents (33,9%) suffer from one type of headache, and is closely followed by a percentage of 27,7% suffering from two associated types and we regrettably noticed an increased frequency of persons preferring to self-medicate. Conclusions: We were, thus, able to demonstrate a close relation between TMD and headache, but we are rather concerned about the fact that a considerably large number of respondents prefer the self-medication option. This is a very alarming issue for the medical system in Romania.
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- 2023
22. Briquette Production from Vineyard Winter Pruning Using Two Different Approaches
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Ioan Ţenu, Radu Roșca, Oana-Raluca Corduneanu, Cecilia Roman, Lacrimioara Senila, Vlad Arsenoaia, Liviu Butnaru, Marius Băetu, Constantin Chirilă, and Petru Marian Cârlescu
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biomass ,renewable energy ,briquettes ,horticultural waste ,sustainability ,Agriculture (General) ,S1-972 - Abstract
Worldwide, different strategies are being developed in order to ensure optimum conditions for the development and growth of economic competitiveness, as well as for increasing the quality of life and environmental protection. All these strategies are closely linked to the development and modernization of systems for producing energy from clean and renewable sources. In this context, the present paper presents the results of research regarding the evaluation of the sustainability of briquette production using biomass resulting from vine winter pruning as the raw material. An analysis of the scientific literature indicates that nearly 8 Mt of biomass would result from the over 7.4 million hectares of vine plantations in the world, biomass that could be valorized through densification in order to produce solid biofuels with a lower calorific value of more than 17 MJ/kg. This study examines the production of briquettes from vineyard winter pruning with consideration of two types of densification technologies: baling and natural drying of the tendrils, and collection, shredding, and artificial drying of the lignocellulose debris. The quality indices and energy consumption and energy efficiency of the briquettes were evaluated to determine their feasibility as an alternative fuel source. When designing the scientific endeavor, the following aspects were considered: defining the aim and objectives of the research; designing the research algorithm; collecting, preparing, and conditioning the biomass; conducting a chemical analysis of the briquettes; and evaluating the energy consumption and energy efficiency for producing the briquettes, taking into account two drying methods (natural and artificial drying). In the meantime, some specific laboratory equipment was designed and built for the artificial drying of biomass, evaluation of mechanical durability, measurement of energy consumption, etc. Analysis of the experimental data has led to the conclusion that the agricultural waste from vine pruning can constitute an important and sustainable source of energy in the form of briquettes that fulfill most of the requirements imposed by international standards.
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- 2024
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23. EFFECT OF GRAPE SKIN POWDER ADDITION ON CHEMICAL, NUTRITIONAL AND TECHNOLOGICAL PROPERTIES OF CHEESE
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Roxana Nicoleta RAȚU, Marius Giorgi USTUROI, Răzvan Mihail RADU-RUSU, Ionuț Dumitru VELEȘCU, Florin Daniel LIPȘA, Vlad Nicolae ARSENOAIA, Alina Narcisa POSTOLACHE, Ioana Cristina CRIVEI, and Petru Marian CÂRLESCU
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food ,functional ,grapes by-products ,quality ,Environmental sciences ,GE1-350 ,Agriculture - Abstract
Large amounts of chemicals with useful properties can be found in by-products of the processing of grapes. Consumer interest in functional foods has increased recently, with dairy products dominating this market. Constituents from grape-based by-products that are naturally occurring in grapes have the potential to enhance the functional qualities of dairy products and lessen environmental damage. As a result, the goal of this research is to provide crucial information on the use of grape skin powder as a helpful ingredient in the manufacture of cheese. In this study, grape skin powder (GSP) was added to cheese to increase its bioactive compounds content and antioxidant activity. Total phenolic content (TPC) was significantly greater in the enriched cheese (5.483±0.443 mg C3G/100 g DW). Adding 2% grape skin powder to the cheese formulation gave an increase of 0.295 mg CE/g DW of TFC and 2.046 mg GAE/g DW of TPC. The GSP-supplemented cheese also showed greater antioxidant activity than the control. This study demonstrates that grape by-products can effectively transfer beneficial compounds to cheese.
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- 2023
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24. Detection of acute promyelocytic leukemia in peripheral blood and bone marrow with annotation-free deep learning
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Petru Manescu, Priya Narayanan, Christopher Bendkowski, Muna Elmi, Remy Claveau, Vijay Pawar, Biobele J. Brown, Mike Shaw, Anupama Rao, and Delmiro Fernandez-Reyes
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Medicine ,Science - Abstract
Abstract While optical microscopy inspection of blood films and bone marrow aspirates by a hematologist is a crucial step in establishing diagnosis of acute leukemia, especially in low-resource settings where other diagnostic modalities are not available, the task remains time-consuming and prone to human inconsistencies. This has an impact especially in cases of Acute Promyelocytic Leukemia (APL) that require urgent treatment. Integration of automated computational hematopathology into clinical workflows can improve the throughput of these services and reduce cognitive human error. However, a major bottleneck in deploying such systems is a lack of sufficient cell morphological object-labels annotations to train deep learning models. We overcome this by leveraging patient diagnostic labels to train weakly-supervised models that detect different types of acute leukemia. We introduce a deep learning approach, Multiple Instance Learning for Leukocyte Identification (MILLIE), able to perform automated reliable analysis of blood films with minimal supervision. Without being trained to classify individual cells, MILLIE differentiates between acute lymphoblastic and myeloblastic leukemia in blood films. More importantly, MILLIE detects APL in blood films (AUC 0.94 ± 0.04) and in bone marrow aspirates (AUC 0.99 ± 0.01). MILLIE is a viable solution to augment the throughput of clinical pathways that require assessment of blood film microscopy.
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- 2023
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25. Phosphorus-Containing Polymer Electrolytes for Li Batteries
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Narcis Varan, Petru Merghes, Nicoleta Plesu, Lavinia Macarie, Gheorghe Ilia, and Vasile Simulescu
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solid polymer electrolytes ,gel polymer electrolytes ,Li-ion batteries ,polyphosphonates ,polyphosphazene ,Production of electric energy or power. Powerplants. Central stations ,TK1001-1841 ,Industrial electrochemistry ,TP250-261 - Abstract
Lithium-ion polymer batteries, also known as lithium-polymer, abbreviated Li-po, are one of the main research topics nowadays in the field of energy storage. This review focuses on the use of the phosphorus containing compounds in Li-po batteries, such as polyphosphonates and polyphosphazenes. Li-po batteries are mini-devices, capable of providing power for any portable gadget. From a constructive point of view, Li-po batteries contain an anode (carbon), a cathode (metal oxide), and a polymer electrolyte, which could be liquid electrolytes or solid electrolytes. In general, a divider is used to keep the anode and cathode from touching each other directly. Since liquid electrolytes have a generally high ionic conductivity, they are frequently employed in Li-ion batteries. In the last decade, the research in this field has also focused on solving safety issues, such as the leakage of electrolytes and risk of ignition due to volatile and flammable organic solvents. The research topics in the field of Li-po remain focused on solving safety problems and improving performance.
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- 2024
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26. Infektionskrankheiten und Protozoenerkrankungen
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Marget, W., Kienitz, M., Stehr, K., Schmid, P. Ch., Oehme, J., Kölle, G., Götz, H., Jírovec, O., Petrů, M., Vanek, E., Von Harnack, G.-A., Opitz, H., editor, Schmid, F., editor, Hellbrügge, Th., editor, Bachmann, K. D., editor, Becker, J., editor, Burmeister, W., editor, Friederiszick, F. K., editor, Frischbier, H.-J., editor, Gött, H., editor, Götz, H., editor, Grüninger, U., editor, Haid, H., editor, Von Harnack, G.-A., editor, Hartung, K., editor, Helbig, D., editor, Helwig, H., editor, Hertel, H. W., editor, Herzig, W., editor, Hockerts, Th., editor, Hövels, O., editor, Hug, O., editor, Jírovec, O., editor, Kaiser, H., editor, Keuth, U., editor, Kienitz, M., editor, Knorr, D., editor, Koch, Fr., editor, Kölle, G., editor, Marget, W., editor, Marx, R., editor, Matthes, A., editor, Menger, W., editor, Moll, H., editor, Mommsen, H., editor, Nitsch, K., editor, Oehme, J., editor, Pechstein, J., editor, Petrů, M., editor, Preuner, R., editor, Reiss, D., editor, Reiter, M., editor, Schmid, P. Ch., editor, Schmidt, G.-W., editor, Schultze, E.-G., editor, Stehr, K., editor, Swoboda, W., editor, Thurau, R., editor, Vanek, E., editor, Wiskemann, A., editor, and Zapp, E., editor
- Published
- 1966
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27. Recovery of Cr from chrome-containing leather wastes to develop aluminum-based composite material along with Al2O3 ceramic particles: An ingenious approach
- Author
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Dwivedi Shashi Prakash, Petru Michal, Saxena Ambuj, Sharma Shubham, Mishra Madhulika, Pramanik Alokesh, Singh Sunpreet, Li Changhe, and Ilyas Rushdan Ahmad
- Subjects
cclw ,collagen ,ball milling ,recycling ,waste material ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Abstract
Leather industries cause soil pollution in terms of leather wastes. Chrome-containing leather wastes (CCLW) also cause various types of pollutions such as air and soil pollution. The utilization of CCLW in the development of aluminum-based composite is the emerging area in the synthesis of materials. In this study, chromium(Cr) in the form of collagen powder was extracted from CCLW. Extracted collagen powder was ball milled with alumina particles for 12.5, 25, 50, 75, and 100 h. The average density of the mixture of ball-milled collagen and alumina particles was reduced by about 1.20% after ball milling for about 100 h. The stir casting technique was employed to develop the aluminum-based composite material. The ball-milled reinforced aluminum-based composite material showed a fair distribution of reinforcement particles as compared without ball-milled reinforced composite material. Tensile strength and hardness of composite material improved by about 35.53 and 46.61%, respectively, after using the mixture of ball-milled 5% collagen powder and 5% alumina particles in the aluminum alloy. However, ductility and toughness were reduced. Corrosion weight loss and thermal expansion of the Al/5% collagen/5% alumina particles with ball-milled composite were found to be 0.022 mg and 5.44 mm3, respectively. X-Ray diffraction of the Al/5% collagen/5% alumina particles with ball-milled composite showed the presence of Al, Al2O3, Cr2O3, and Cr phases. The presence of hard phases such as Al2O3, Cr2O3, and Cr was responsible for enhancing the hardness and tensile strength of the composite. The developed composite material can be utilized in the fabrication of engine blocks, connecting rods, and piston rings.
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- 2022
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28. Red Onion Peel Powder as a Functional Ingredient for Manufacturing Ricotta Cheese
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Florin Daniel Lipșa, Florina Stoica, Roxana Nicoleta Rațu, Ionuț Dumitru Veleșcu, Petru Marian Cârlescu, Iuliana Motrescu, Marius Giorgi Usturoi, and Gabriela Râpeanu
- Subjects
red onion powder ,anthocyanins ,antioxidant activity ,natural ingredients ,value-added products ,Chemical technology ,TP1-1185 - Abstract
Onion (Allium cepa L.) is a vegetable widely cultivated and consumed due to its rich content in bioactive compounds. Red onion peel (ROP) powder, which is a by-product derived from the onion industry, has been attracting significant interest as a potential functional ingredient for improving the overall quality of foods. The present study explores the potential of ROP powder as a functional ingredient to improve the quality and nutritional value of whey cheese. Despite being frequently viewed as a food processing waste byproduct, ROP is a rich source of bioactive substances, including antioxidants, flavonoids, and dietary fiber, having antioxidant and antibacterial effects. The ROP extract exhibited high amounts of total polyphenols (119.69 ± 2.71 mg GAE/g dw) and antioxidant activity (82.35 ± 1.05%). Different quantities (1 and 3%) of ROP powder were added to cheese formulations, and the subsequent impact on the texture characteristics, sensory attributes, and phytochemical composition of the value-added cheeses was evaluated. The findings show that the addition of ROP powder improved the texture and the color of the cheeses, providing a visually appealing product. Additionally, adding the ROP powder significantly raised the amount of phytochemicals and antioxidant activity (17.08 ± 0.78 µmol TE/g dw for RCROP1, 24.55 ± 0.67 µmol TE/g dw for RCROP2) in the final product’s formulation. Moreover, adding powder to cheese is an effective way to increase the value of onion by-products and produce polyphenol-enriched cheese.
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- 2024
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29. Ancient mitochondrial protein secretion
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HORVÁTHOVÁ L., ŽÁRSKÝ V., DERRELLE R., KRUPIČKOVÁ A., KLÁPŠŤOVÁ V., VOLEMAN L., PETRŮ M., ELIÁŠ M., PÁNEK T., ČEPIČKA I., HUYSMANS G., CHAMI M., FRANCETIC O., and DOLEŽAL P.
- Published
- 2016
30. Effect of nanoadditives on the novel leather fiber/recycled poly(ethylene-vinyl-acetate) polymer composites for multifunctional applications: Fabrication, characterizations, and multiobjective optimization using central composite design
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Sharma Shubham, Sudhakara P., Petru Michal, Singh Jujhar, and Rajkumar S.
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recycled eva ,leather buffing dust ,rolling and compression molding ,central composite designs ,footwear, and leather ancillaries(s) application ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Published
- 2022
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31. Network topological determinants of pathogen spread
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María Pérez-Ortiz, Petru Manescu, Fabio Caccioli, Delmiro Fernández-Reyes, Parashkev Nachev, and John Shawe-Taylor
- Subjects
Medicine ,Science - Abstract
Abstract How do we best constrain social interactions to decrease transmission of communicable diseases? Indiscriminate suppression is unsustainable long term and presupposes that all interactions carry equal importance. Instead, transmission within a social network has been shown to be determined by its topology. In this paper, we deploy simulations to understand and quantify the impact on disease transmission of a set of topological network features, building a dataset of 9000 interaction graphs using generators of different types of synthetic social networks. Independently of the topology of the network, we maintain constant the total volume of social interactions in our simulations, to show how even with the same social contact some network structures are more or less resilient to the spread. We find a suitable intervention to be specific suppression of unfamiliar and casual interactions that contribute to the network’s global efficiency. This is, pathogen spread is significantly reduced by limiting specific kinds of contact rather than their global number. Our numerical studies might inspire further investigation in connection to public health, as an integrative framework to craft and evaluate social interventions in communicable diseases with different social graphs or as a highlight of network metrics that should be captured in social studies.
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- 2022
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32. Polyethyleneimine-impregnated activated carbon nanofiber composited graphene-derived rice husk char for efficient post-combustion CO2 capture
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Che Othman Faten Ermala, Yusof Norhaniza, Petrů Michael, Md Nordin Nik Abdul Hadi, Hamid Muhammad Faris, Ismail Ahmad Fauzi, Rushdan Ahmad Ilyas, and Abu Hassan Shukur
- Subjects
activated carbon nanofibers ,carbon dioxide adsorption, graphene-derived rice husk char ,nanocomposites ,polyethyleneimine ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Abstract
This study presents the fabrication of polyethyleneimine (PEI)–graphene-derived rice husk char (GRHC)/activated carbon nanofiber (ACNF) composites via electrospinning and physical activation processes and its adsorption performance toward CO2. This study was performed by varying several parameters, including the loading of graphene, impregnated and nonimpregnated with amine, and tested on different adsorption pressures and temperatures. The resultant ACNF composite with 1% of GRHC shows smaller average fiber diameter (238 ± 79.97 nm) with specific surface area (S BET) of 597 m2/g, and V micro of 0.2606 cm3/g, superior to pristine ACNFs (202 m2/g and 0.0976 cm3/g, respectively). ACNF/GRHC0.01 exhibited CO2 uptakes of 142 cm3/g at atmospheric pressure and 25°C, significantly higher than that of pristine ACNF’s 69 cm3/g. The GRHC/ACNF0.01 was then impregnated with PEI and further achieved impressive increment in CO2 uptake to 191 cm3/g. Notably, the adsorption performance of CO2 is directly proportional to the pressure increment; however, it is inversely proportional with the increased temperature. Interestingly, both amine-impregnated and nonimpregnated GRHC/ACNFs fitted the pseudo first-order kinetic model (physisorption) at 1 bar; however, best fitted the pseudo second-order kinetic model (chemisorption) at 15 bar. Both GRHC/ACNF and PEI-GRHC/ACNF samples obeyed the Langmuir adsorption isotherm model, which indicates monolayer adsorption. At the end of this study, PEI-GRHC/ACNFs with excellent CO2 adsorption performance were successfully fabricated.
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- 2022
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33. A SEM-EDX Study on the Structure of Phenyl Phosphinic Hybrids Containing Boron and Zirconium
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Petru Merghes, Narcis Varan, Gheorghe Ilia, Iosif Hulka, and Vasile Simulescu
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sol–gel synthesis ,organic–inorganic hybrids ,phenyl phosphinic acid ,zirconium ,boron ,SEM-EDX ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
The SEM-EDX method was used to investigate the structure and morphology of organic–inorganic hybrids containing zirconium, boron and phosphorus compounds, synthesized by the sol–gel method. We started by using, for the first time together, zirconyl chloride hexa-hydrate (ZrOCl2·6H2O), phenyl phosphinic acid and triethyl borate as precursors and reagents, at different molar ratios. The obtained hybrids showed a very high thermal stability and are not soluble in water or in organic solvents. As a consequence, such hybrid solid materials are suitable for applications at high temperatures. The obtained hybrids have complex 3D structures and form organic–inorganic networks containing Zr-O-Zr, Zr-O-P and Zr-O-B bridges. Such organic–inorganic networks are also expected to form supramolecular structures and to have many potential applications in different fields of great interest such as catalysis, medicine, agriculture, energy storage, fuel cells, sensors, electrochemical devices and supramolecular chemistry.
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- 2023
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34. COMPARISON OF TWO MICROWAVE DRYING TECHNIQUES FOR CEREAL SEEDS AND DETERMINATION OF THEIR PHYSICAL PARAMETERS
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Petru Marian CÂRLESCU, Marius BĂETU, Virginia CIOBANU, Ioan ȚENU, and Radu ROȘCA
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microwave ,drying ,cereal seeds ,Environmental sciences ,GE1-350 ,Agriculture - Abstract
The microwave drying of wheat and corn seeds by two technologies at different working powers is studied here. The main objective is to evaluate the effect of microwaves on variations in the moisture, colour and size of the seeds after microwave drying. The tests are performed in microwave ovens with and without inverter technology at three drying powers (260, 440 and 620 W). It has been observed that increasing drying power results in a ~50% reduction in drying time and a seed moisture level below 14%. The colour variation of the seeds is insignificant between microwave drying with and without the inverter. However, there is also an unacceptable decrease in size for both types of seeds with increasing drying power, which can lead to increased shrinkage of the seeds and the appearance of cracks, especially in the corn seeds.
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- 2021
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35. Mechanical, morphological, and fracture-deformation behavior of MWCNTs-reinforced (Al–Cu–Mg–T351) alloy cast nanocomposites fabricated by optimized mechanical milling and powder metallurgy techniques
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Sharma Shubham, Patyal Vikas, Sudhakara P., Singh Jujhar, Petru Michal, and Ilyas R. A.
- Subjects
al–cu–mg–t351 alloy ,powder metallurgy ,sintering ,extrusion ,fractography ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Abstract
The carbon nanotube (CNT) is becoming more popular due to their low-density, high-strength etc. Among CNTs, multi-walled carbon nanotubes (MWCNTs) are gaining more importance due to their enhanced thermal and electrical conductivity. The present research is exploring the applicability of MWCNTs reinforced with AA2024-T351 alloys for electromechanical applications. This study is currently undertaken for using MWCNTs as a reinforcing particulate for the purpose to enhance the characteristics including low density, high strength, and hardness together with excellent thermal and electrical conductivity of the aluminum alloy matrices. Therefore, this article provides a state-of-the-art experimental approach to fabricate and furthermore, to evaluate the mechanical characteristics, microstructural analysis, and fatigue behavior of Al–Cu–Mg–T351/MWCNT composites under both the mechanical and thermal loading by utilizing powder technology processing route. The uniform dispersion of CNTs has been exposed using ball milling process. Results revealed that the MWCNTs provide extraordinary synergistic strength, enhances fatigue resistance, creep resistance, ductility, and other mechanical characteristics of the aluminum-based composites. The mechanical loading of the composite exhibited increased properties as compared to thermal-loaded aluminum-MWCNT composites. Findings conclude that the maximum hardness of 35Hv obtained for sintered AA2024-T351 and 45Hv for 0.5% MWCNT heat-treated samples indicate that the addition of MWCNT enhances the hardness which may be because CNT is evenly dispersed at the interfacial space. Maximum UTS of 105.21 MPa was obtained with 0.5% MWCNT for sintered composites. Microstructural analysis of the Al–Cu–Mg–T351/MWCNTs composite exhibits reasonably uniform distribution, void formation, and good interfacial bonding. X-ray Diffraction method patterns of fabricated composite shows that the CNT is present at 2β = 23.6 and 44.6°, whereas high peaks of aluminum are present at uniform dispersed positions. Transmission electron magnifying instrument study further substantiates the above research. Fracture micrographs of the Al–Cu–Mg–T351/MWCNTs composite portray the resistant nature of the nanotubes due to the presence of CNTs, Al–Cu, and aluminum carbide elements in the alloy and the reactions that happened during heat treatment. This significant improvement was attributed to the shear interactions among the constituents and high load carrying capacity of the CNT, uniform dispersion, and interface bond strength among the matrix and constituents. The findings in the study will undoubtedly be beneficial for the development of high-strength, MWCNTs/Al–Cu–Mg–T351, matrix composites in future for multifunctional applications on broader spectrum.
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- 2021
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36. Numerical model describing optimization of fibres winding process on open and closed frame
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Petrů, M, primary, Mlýnek, J, additional, and Martinec, T, additional
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- 2016
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37. Effects of Dairy Cows Management Systems on the Physicochemical and Nutritional Quality of Milk and Yogurt, in a North-Eastern Romanian Farm
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Roxana Nicoleta Rațu, Petru Marian Cârlescu, Marius Giorgi Usturoi, Florin Daniel Lipșa, Ionuț Dumitru Veleșcu, Vlad Nicolae Arsenoaia, Andreea Mihaela Florea, Marius Mihai Ciobanu, Răzvan-Mihail Radu-Rusu, Alina Narcisa Postolache, and Daniel Simeanu
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cows feeding ,milk ,yogurt ,fatty acids ,quality ,Agriculture (General) ,S1-972 - Abstract
The study’s objective was to investigate changes in the fatty acid composition of cow milk in general and in 80 Romanian Spotted cows’ husbandry and feeding systems in particular (grazing–GC group vs. stabulation–SC group). The ultimate objective was to determine if the changes that happened in the milk also transferred to the finished product. Also, the influence of the quality of raw milk produced by both systems was evaluated when yogurt was made from it. The milk was gathered in May, July and September and used for both the yogurt-making process and the study, which lasted from May to October. In comparison to milk from SC, milk from grazed caws had larger percentages of fat and dry matter throughout the summer (GC) season. Moreover, pasture-based rations (MGC) contained more PUFA than MCS did. Data research revealed that not only do factors such as milk origin and initial quality have a substantial impact on yogurt quality parameters, but also technologies such as milk fermentation have a considerable impact on the fatty acid profile of yogurt. In comparison to cows kept permanently in stables, grazed cows (MGC) had fat with a lower concentration of saturated fatty acids and a higher proportion of rumenic, vaccenic and oleic acids (MSC). When fresh milk is processed into yogurt and other dairy products, the fatty acid profiles alter, with saturated fatty acids predominating over unsaturated ones. The findings show that pasture-fed cows have a positive impact on milk quality, particularly in terms of fatty acid profile, as well as on yogurt’s ultimate nutritional and dietary quality.
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- 2023
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38. A retrospective of surgical pathology, care problems specific to oncological and non-oncological cases, in a year of the COVID-19 pandemic
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Mirela Mariana Valcan, Petru Mihancea, and Bogdan Buhas
- Subjects
surgical pathology ,comorbidities ,care problems ,covid-19 pandemic ,Medicine (General) ,R5-920 ,Surgery ,RD1-811 - Abstract
Introduction. The activity carried out in a general surgery department is complex, the diversity of cases and comorbidities such as cardiovascular diseases, neuro-mental disorders, metabolic diseases, obesity, diabetes influence the care needs of patients. These pathologies increase risks and safety issues in the context of the COVID-19 pandemic. Material and method. We conducted a descriptive retrospective study in which we included 749 patients, of which 184 patients with oncological diseases and 565 with non-oncological diseases, hospitalized at the level of Surgery II, Oradea County Emergency Clinical Hospital, between 15.03.2020 and 15.03.2021. We analyzed the cases of the department in terms of demographic data, oncological and non-oncological cases, comorbidities, types of interventions performed, type of hospitalization, length of hospitalization, mortality, care problems, using FOCG records, care plan and its annexes. Results. 610 surgeries were performed in 749 patients, with an operability rate of 81%. 151 surgeries were performed in the first 24 hours after hospitalization, with or without the result of the RT-PCR test for SARSCoV-2, representing 28% of cases, with additional protection measures and overloading of staff. Of the 184 patients with oncological diseases, 64 were hospitalized by appointment, breast cancer predominates and 120 cases by the emergency department, colorectal cancer predominates. The most common complications in non-oncological surgical cases were: acute cholecystitis with pancreatic reaction, angiocolitis, mechanical jaundice, perforated gallbladder with subhepatic abscess, gastric ulcer perforated with peritonitis, strangulated eventration with loop necrosis, check perforation, occlusions intestinal with severe hydroelectrolytic and metabolic imbalances, septic conditions. Patients with oncological effects presented complications such as: perforated colon cancer with fecal peritonitis, rectal cancer with anal stenosis and rectoria, gastric cancer with upper digestive hemorrhage, pancreatic cancer with mechanical jaundice, intestinal occlusion, esophageal cancer with complete stenosis, cachexia, severe nutritional and metabolic imbalances. Regarding comorbidities, the most common secondary diagnoses associated with the underlying disease were: cardiovascular disease, diabetes, endocrine disorders, neurological and/or psychiatric disorders, obesity, lung disorders. Conclusions. The COVID-19 pandemic made surgical care more difficult due to the rules imposed, the number of hospitalizations decreased, patients delayed the operative moment, with a great impact on the subsequent evolution of the quality of life and survival. In addition to the specific problems of surgical emergencies and oncological cases, a problem for staff was the provision of preoperative and postoperative surgical care to patients with comorbidities such as neuro-mental disorders, metabolic diseases, obesity, diabetes, pathologies that increased risks and safety issues. In the context of the COVID-19 pandemic, the increase in the need for care led to the increase in the consumption of human and material medical resources.
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- 2021
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39. Experimental and Modelling Studies on Thermal Insulation and Sound Absorption Properties of Cross-Laid Nonwoven Fabrics
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Yang Tao, Hu Lizhu, Xiong Xiaoman, Petrů Michal, Palanisamy Sundaramoorthy, Yang Kai, Novák Jan, and Militký Jiří
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thermal insulation ,sound absorption ,nonwoven ,polyester ,Textile bleaching, dyeing, printing, etc. ,TP890-933 - Abstract
Nonwoven fabrics are widely used for thermal insulation and sound absorption purpose in construction and automobile fields. It is essential to investigate their thermal conductivity and sound absorption coefficient. Five cross-laid nonwoven fabrics are measured on the Alambeta device and Brüel & Kjær impedance tube. Bogaty and Bhattacharyya models are selected to predict the thermal conductivity, and Voronina and Miki models are used to predict the sound absorption coefficient. The predicted thermal conductivity shows a significant difference compared with the measured values. It is concluded that Bogaty and Bhattacharyya models are not suitable for high porous nonwoven fabric. In addition, the results of Voronina and Miki models for sound absorption prediction are acceptable, but Voronina model shows lower mean prediction error compared with Miki model. The results indicate that Voronina model can be used to predict the sound absorption of cross-laid nonwoven fabric.
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- 2021
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40. Thermal Behavior of Aerogel-Embedded Nonwovens in Cross Airflow
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Xiong Xiaoman, Venkataraman Mohanapriya, Jašíková Darina, Yang Tao, Mishra Rajesh, Militký Jiří, and Petrů Michal
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nonwoven fabrics ,silica aerogel ,cross airflow ,heat transfer coefficient ,Textile bleaching, dyeing, printing, etc. ,TP890-933 - Abstract
Thermal performance of aerogel-embedded polyester/polyethylene nonwoven fabrics in cross airflow was experimentally studied by using a laboratory-built dynamic heat transfer measuring device in which the fabric could be applied on a heating rod. Experiments were performed with different airflow velocities and heating conditions. The temperature–time histories of different materials were collected and compared. The temperature difference and convective heat transfer coefficient under continuous heating were analyzed and discussed. Results showed that under preheated conditions, the aerogel-embedded nonwoven fabrics had very small decrease in temperature and good ability to prevent against heat loss in cross flow. As for the continuous heating conditions, the heat transfer rate of each material showed an increasing trend with increase in the Reynolds number. The aerogel-treated nonwoven fabric with the least fabric thickness and aerogel content delivered a significantly increased heat transfer rate at higher Reynolds number. Thicker fabrics with higher aerogel content could provide better insulation ability in cross flow.
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- 2021
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41. Research on the Process of Convective Drying of Apples and Apricots Using an Original Drying Installation
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Ionuț Dumitru Veleșcu, Roxana Nicoleta Rațu, Vlad-Nicolae Arsenoaia, Radu Roșca, Petru Marian Cârlescu, and Ioan Țenu
- Subjects
fruits ,convective drying ,moisture content ,quality ,color ,Agriculture (General) ,S1-972 - Abstract
After being harvested, fresh apples and apricots have a high moisture content and are put through a drying process to reduce waste and lengthen shelf life. This study intends to evaluate the physicochemical parameters during moisture removal and product heating in order to conduct an experimental investigation of the convective drying of apples and apricots in a pilot drying installation. The drying agent’s temperature and/or speed can be adjusted using the pilot installation. About the raw materials: the apricots (Neptun variety) were dried and cut into halves, while the apples (Golden Delicious variety) were dried and cut into 4 mm thick slices. The fruits’ drying properties were observed at 50 °C, 60 °C, 70 °C, and 80 °C, air speeds of 1.0, 1.5, and 2.0 m/s, and relative air humidity levels of 40–45%. Findings of the ascorbic acid content, color, heating, and dimensional fluctuations are provided and examined. Increased air velocity and temperature had the expected effect of increasing water loss, solid gain, and shrinking. Depending on the drying conditions, different color characteristics were applied.
- Published
- 2023
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42. Studies on the Physical Changes in Corn Seeds during Hybrid Drying (Convection and Microwave)
- Author
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Petru Marian Cârlescu, Mihai-Marius Băetu, Radu Roșca, and Ioan Țenu
- Subjects
moisture ,stress crack ,stiffness ,color ,Agriculture (General) ,S1-972 - Abstract
Hybrid seed drying technology, based on convection and microwave drying, is a modern method, and the research on the physical changes in cereal seed resulting from hybrid drying is still in its infancy. The aim of the present paper is to study the uniformity of the drying process by examining the physical changes occurring in corn seeds. An innovative drying equipment, combining convective and microwave drying, was used to dry corn seeds (variety DKC5068). The convective drying was performed during the pneumatic transport of the seeds, using hot air at a maximum temperature of 50 °C; the microwave-based drying was performed using 2.45 GHz microwaves. Thus, the seeds were volumetrically heated at a temperature which does not exceed 44 °C. The physical changes in corn seeds were measured in terms of moisture, volume, cracking and color. The results regarding the moisture and volume changes in the seeds during the drying process proved that moist seeds are more homogeneous than dry seeds. The change in volume also changed the stiffness of the seeds, which showed greater homogeneity after drying compared to wet seeds. Hybrid drying led to an average shrinkage of 8.76% compared with the original seed volume, while the percentage of seeds showing cracks after drying increased by 22%. Generally, the drying process also led to color changes, but in the case of hybrid drying the results were inconclusive. Hybrid drying of corn seeds requires a shorter time and does not significantly influence physical characteristics, compared to other drying technologies.
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- 2023
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43. Wittig and Wittig–Horner Reactions under Sonication Conditions
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Gheorghe Ilia, Vasile Simulescu, Nicoleta Plesu, Vlad Chiriac, and Petru Merghes
- Subjects
Wittig reaction ,Wittig–Horner synthesis ,ultrasound ,carbonyl olefination ,Organic chemistry ,QD241-441 - Abstract
Carbonyl olefinations are among the most important organic syntheses that form C=C bonds, as they usually have high yields and in addition offer excellent stereoselectivity. Due to these advantages, carbonyl olefinations have important pharmaceutical and industrial applications. These reactions contain an additional step of an α-functionalized carbanion to an aldehyde or ketone to produce alkenes, but syntheses performed using metal carbene complexes are also known. The Wittig reaction is an example of carbonyl olefination, one of the best ways to synthesize alkenes. This involves the chemical reaction between an aldehyde or ketone with a so-called Wittig reagent, for instance phosphonium ylide. Triphenylphosphine-derived ylides and trialkylphosphine-derived ylides are the most common phosphorous compounds used as Wittig reagents. The Wittig reaction is commonly involved in the synthesis of novel anti-cancer and anti-viral compounds. In recent decades, the use of ultrasound on the Wittig reaction (and on different modified Wittig syntheses, such as the Wittig–Horner reaction or the aza-Wittig method) has been studied as a green synthesis. In addition to the advantage of green synthesis, the use of ultrasounds in general also improved the yield and reduced the reaction time. All of these chemical syntheses conducted under ultrasound will be described further in the present review.
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- 2023
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44. Infektionskrankheiten und Protozoenerkrankungen
- Author
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Marget, W., primary, Kienitz, M., additional, Stehr, K., additional, Schmid, P. Ch., additional, Oehme, J., additional, Kölle, G., additional, Götz, H., additional, Jírovec, O., additional, Petrů, M., additional, Vanek, E., additional, and von Harnack, G.-A., additional
- Published
- 1966
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45. Experimental swine models for perforator flap dissection in reconstructive microsurgery.
- Author
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Alexandru Nistor, Lucian P Jiga, Gratian D Miclaus, Bogdan Hoinoiu, Petru Matusz, and Mihai E Ionac
- Subjects
Medicine ,Science - Abstract
BackgroundPerforator flaps account for a fraction of reconstructive procedures despite their growing popularity. Specific microsurgical skills are required for successful harvesting of perforator flaps, which are difficult to attain through direct operating room training. Cadaver and small animal dissection cannot simulate human perforator dissection, lacking either bleeding and vessel feedback or providing too small calibers. Thus, we have developed and refined over the last ten years five perforator flaps models in living pig, described their harvesting technique and provided evidence for their effectiveness as perforator flap training models.MethodCT angiography data from ten living pigs was used for detailed examination of the integument's vascular anatomy. Microsurgical techniques were used to standardize and harvest the perforator flaps in acute models. The same operator-assistant team, with no prior perforator flap harvesting experience, raised all flaps in a sequential manner, one animal per day, during a 7 weeks timespan. Porcine flaps were compared to human counterparts in terms of vessel caliber, dissection times. Immediate flap survival was measured as duration of perforator pulsation after completion of flap harvesting, measured every 10 minutes for up to two hours.ResultsFive perforator flaps were standardized, based on the deep cranial epigastric, thoracodorsal, lateral intercostal, cranial gluteal and dorsal cervical arteries and the operative technique was described in detail. Mean pig perforator size was 1.24±0.36 mm and mean pedicle diameter was 2.78±0.8 mm, which matched closely the human calibers for each flap. Total harvesting time increased 22.4% between the first two experiments due to a more cautious approach following the lack of perforator pulsation in all flaps in the first experimental animal. A total decrease of 44.4% harvesting time between second and last experiment was observed, as expected with all repetitive surgical procedures. Post-operative perforator pulsation time revealed a steep learning curve, with no or short-term pulsatile perforators in the first five pigs, followed by a 275% increase in total perforator pulsation time between 5th and 6th experimental animal. Based on these findings we provide a description of the most common mistakes, their consequences and gestures which can be trained using the pig perforator flaps, in order to overcome these mistakes.ConclusionThese five pig perforator flap models provide a fast and efficient learning tool to develop perforator flap harvesting skills safely. Surgical training using these five experimental models offers a similar hands-on perforator flap dissection experience as with human tissue, based on the similar sized calibers of both perforators and pedicles with their human counterparts.
- Published
- 2022
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46. The Influence of Boron on the Structure and Properties of Hybrid Compounds Containing Zirconium and Phosphorus
- Author
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Petru Merghes, Gheorghe Ilia, Iosif Hulka, Vlad Chiriac, Narcis Varan, and Vasile Simulescu
- Subjects
sol–gel ,organic–inorganic hybrid materials ,boron ,zirconium ,phosphorus ,inorganic polymers ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
In the present work, novel organic–inorganic hybrid materials containing boron, zirconium, and phosphorus were synthesized at different molar ratios, using the sol–gel method, starting from zirconyl chloride hexa-hydrate, triethyl borate, and phenyl phosphonic acid as the precursors. The sol–gel process is used for the first time in the present work in order to obtain organic–inorganic hybrids (or the so-called inorganic polymers) containing together boron, zirconium, and phosphorus. The sol–gel syntheses were performed at room temperature in ethanol. Zirconium containing compounds are already well known for their applications in medicine in restorative or prosthetic devices, including dental implants, knee and hip replacements, middle-ear ossicular chain reconstruction, and so on. Zirconium is a strong transition metal, which started to replace hafnium and titanium in the last decade in important applications. On the other hand, boron has the capability (similar to carbon) to form stable covalently bonded molecular networks. In addition to this capability, boron also offers mixed metallic and nonmetallic properties, because of its place on the periodic table, at the border between metals and nonmetals. Boron is responsible for the higher thermal stability of synthesized hybrid compounds. In the structure of those hybrid compounds, zirconium, boron, and phosphorus atoms are always connected via an oxygen atom, by P-O-Zr, Zr-O-Zr, or Zr-O-B bridges.
- Published
- 2022
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47. Numerical Study Regarding the Seismic Response of a Moment-Resisting (MR) Reinforced Concrete (RC) Frame Structure with Reduced Cross-Sections of the RC Slabs
- Author
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Ion Sococol, Petru Mihai, Tudor-Cristian Petrescu, Florin Nedeff, Valentin Nedeff, Maricel Agop, and Bogdan-Ionel Luca
- Subjects
FEM analysis ,pushover ,RC slabs ,frame structure ,vertical holes ,plastic zones ,Building construction ,TH1-9745 - Abstract
In the first part of the current study, the effectiveness of the transversal cross-section reduction method for RC beams in marginal areas (by means of mechanical drilling) was validated. The said method “encourages” the formation of plastic hinges at the beam ends and, at the same time, allows for taking into account the bending stiffness of RC slabs, which is exerted upon the RC beams. In these conditions, the second part of the current research study (i.e., the current manuscript) highlights the real mode of reducing the lateral stiffness of the slabs upon the RC beams. These elements form a common body, together with the beam–column frame node. The same method as in the first part of the study—“weakening” the plates in the corner area through vertical drilling, without affecting the integrity of the reinforcing elements—was used. The analytical MR RC frame model, studied by means of the comparative method, highlights the efficiency of the transversal cross-section reduction method for RC slabs. Basically, the directing of the plastic deformations from the weakened slab areas towards the marginal areas of the reinforced concrete beams takes place. The beams rotate as far as the weakened slab areas allow its plastic deformation, thus being possible to observe the partial conservation effect of the beam–column frame joint. Furthermore, for the analytical model with the maximum number of vertical holes in the corner areas of the concrete plate, minimal plastic deformations are recorded for the marginal areas of the concrete columns. A partial conservation of the formation mechanism of the “beam-slab-frame node” common rigid block is also noted. Consequently, the dissipation of the seismic energy is made in a partially controlled and directed manner, in the “desired” areas, according to the “Strong Columns—Weak Beams” (SCWB) ductile mechanism of the lateral behavior to seismic actions for reinforced concrete frame structures. The mechanism is specified in current design norms for RC frame systems. The effectiveness of the method for reducing the transversal section of the RC plates in the corner areas by means of transversal drilling is highlighted and validated from the perspective of the local and global ductile seismic response of reinforced concrete frame structures. A significant reduction in the bending stiffness of the slabs upon the beams and a real development of the plastic hinges in the marginal areas of the beams (together with partial implications and plastic deformations) were observed.
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- 2022
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48. Altered mandibular dynamics between bruxism and temporomandibular joint dysfunction
- Author
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Daiana DEBUCEAN, Petru MIHANCEA, and Marius S. POP
- Subjects
temporomandibular joint ,limited mandible opening ,bruxism ,myofunctional therapy ,pain ,Medicine ,Medicine (General) ,R5-920 - Abstract
Introduction. The face and its associated structures (cranial, oral, dental) form one of the most complex areas of the human body, hence the diversity of the anatomical and functional pathologies at this level. Sometimes, the approach from the perspective of only one medical specialization may lead to symptomatology improvement or even remittance, but there are many situations when relapse occurs over time; the effect was treated, but not the cause in its totality. Proper diagnosis, selection and implementation of the most appropriate therapeutic approach require the involvement and collaboration of a multidisciplinary team. The objective of the study was to highlight the advantage of combining manual therapy and myofunctional therapy, along with general relaxation, in patients with a mandible opening limitation in order to regain the harmony of the neuromuscular control and temporomandibular arthrokinematics. Material and methods. 46 patients were divided into 3 groups: group 1 benefited from manual therapy alone, group 2 only myofunctional therapy; group 3, manual therapy together with myofunctional therapy. Results. The data confirm the increased efficacy of the combined therapy used with group 3 compared to the groups where only one type of therapy was applied. Therefore, it is confirmed the importance of involving the multidisciplinary team in addressing the patient with temporomandibular joint dysfunctions. Conclusions. The short- and medium-term outcomes of combined therapy demonstrate the reduction of symptoms without recurrence, an improvement in dental functioning and, as a consequence, an increase in the quality of life of this patient population.
- Published
- 2019
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49. Analytical Study Regarding the Seismic Response of a Moment-Resisting (MR) Reinforced Concrete (RC) Frame System with Reduced Cross Sections of the RC Beams
- Author
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Ion Sococol, Petru Mihai, Tudor-Cristian Petrescu, Florin Nedeff, Valentin Nedeff, and Maricel Agop
- Subjects
RC frame system ,push-over analysis ,reduced cross section ,vertical holes ,plastic hinges ,Building construction ,TH1-9745 - Abstract
In the last few decades, a series of earthquakes were recorded which pointed out several deficiencies regarding the ductile seismic response of MR RC frame structures. Thus, the research problem centres around the failure mechanisms registered by the structures, which differ from the general notions of seismic response commonly found in current design standards and norms regarding seismic actions. In these conditions, in the present paper—by using comparative methods—the analytical validation of the solution of plastic hinge concentration and seismic energy dissipation in the marginal beam areas is proposed. Therefore, the RC beam sections were reduced (weakened) in the marginal areas which exhibit a plastic deformation potential, as well as in the corner areas of concrete slabs with vertical rectangular holes. The significant outcomes of this research imply the partial “guiding” of plastic hinges in the zones adjacent to beam ends. Furthermore, a reduction of both the negative effects of horizontal rigidization of the beams and the cracking and plastic deformation effects of beam-column frame joints was observed. With these technical implications, a complex mechanism of plastic deformation of MR RC frame models is registered in which all lateral elements (including RC columns) participate in the dissipation of seismic energy, without the occurrence of the “weak storey” mechanism for any of the analytical RC frame models. Furthermore, it is possible to observe the partial formation of the global plastic mechanism “Strong Columns—Weak Beams” (SCWB) for some of the structural models. Finally, the analytically studied innovative element regarding the improvement of the seismic response of pure MR RC frame structures is successfully validated.
- Published
- 2022
- Full Text
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50. An Open-Label Trial Study of Quality-of-Life Assessment in Irritable Bowel Syndrome and Their Treatment
- Author
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Bogdana Ariana Alexandru, Lavinia Alina Rat, Andrada Florina Moldovan, Petru Mihancea, and Lavinia Mariș
- Subjects
irritable bowel syndrome ,neurotransmitters ,probiotics ,quality of life ,Medicine (General) ,R5-920 - Abstract
Background and objectives: Irritable bowel syndrome (IBS) does not only have a complex pathophysiological evolution with central and peripheral mechanisms. This study aimed to monitor the neuropsychiatric part of IBS and its management, following the quality of life of patients with IBS. Materials and Methods: Participants numbering 145 were investigated in this study for 6 months and were divided into four groups, namely the control group with a symptomatic period of less than 6 months (n = 34), the group with irritable bowel syndrome (IBS; n = 58), IBS and neuropsychiatric treatment (n = 32), and IBS with probiotic treatment (n = 22). Clinical and paraclinical analyses as well as quality of life were monitored by domestic and international psychological questionnaires. Results: It was observed that, in patients with pro-longed symptoms, neuropsychiatric impairment occurred more frequently, and both clinical and paraclinical analyses improved significantly (p < 0.05) more so in those with complex allopathic treatment and in those with probiotic treatment. There were no significant differences between the two research groups. Conclusions: It has been shown that the neuropsychological component of IBS plays an important role in its treatment, and modern probation therapy can achieve similar results to those of neuropsychiatry. This also requires further studies to ensure the best combination in the approach to IBS.
- Published
- 2022
- Full Text
- View/download PDF
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