bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods of Obtaining and Physicochemical Properties of Modified Carbonaceous Sorbents
Authors: Svietkina Olena , Netiaga Olga , Tarasova Hanna , Ustymenko Ievgenii , Cabana Edgar Caseres
Published: September 2021

The variety of practical problems solved in recent years with the help of sorption methods requires expanding the range of used adsorbents. Active carbons are very promising porous adsorbents. Due to a whole complex of valuable properties of a highly developed porous structure, a variety of the chemical nature of the surface, special electrophysical properties, as well as chemical, thermal and radiation resistance, various active carbons are widely used for the absorption of gaseous and dissolved substances. The peculiar nature of carbon adsorbents contributes to the fact that solutes on coal can be adsorbed by completely different; mechanisms, their sorption may be due to the different nature of the forces involved in the adsorption process. The purpose of the work is to obtain multipurpose sorbents; to study methods of modification of carbonaceous sorbents from ash waste, as well as their physicochemical properties
Energy and Resources Recovery from Gasified Screenings and Toxic Sludge
Authors: Bunge Siviwe H. , Topkin James L. , Gorimbo Joshua , Nkazi Diakanua
Published: September 2021

Sludge and screenings management is increasingly becoming a dilemma due its accumulating and tightening environmental regulations that limit its disposal methods. Various sludge management options have been researched, ranging from incineration, thermochemical liquefaction, to pyrolysis and gasification. This work proposes syngas, bio-oil, chemical resources and bio-char production for beneficiation through gasification of a mixture of sludge and screenings at different ratios of 25/75, 50/50 and 75/25. It also studies mass loss and toxins possible destruction by gasification temperatures and reactions. Toxicity and CHNS analysis before and after gasification were aimed at finding sludge energy content, while thermogravimetric analysis (TGA), was to find sampling and stopping temperatures during gasification. The overall best results of high syngas quality (high LHV, H2, CO and CH4 contents) and high quality bio-oil (i.e. cleanest, with high crude oil equivalent bonds such as C1 up to C36 and higher applicable bio-oil resources and chemical species obtained) was achieved by a 75/25 ratio, followed by a 50/50 ratio. The results also showed some possibility of biological and chlorinated hydrocarbon toxins (PCBs and PAHs) break down as well as the reduction of sludge and screenings to about 32% of the initial mass. These results can be further investigated for syngas application in power generation and liquid fuel production. Char toxicity can be analysed for its application in agriculture and for its adsorption properties. Char can be analysed for the presence of metals in it.
Comparative Studies on Mechanical Performance of Epoxy and Polyester Hybrid Composites with Jute and Glass Layers
Authors: Thakur Amit Kumar , Kaviti Ajay Kumar , Aseer J. Ronald
Published: September 2021

The natural fibers are the alternative to glass and other human-made fibers, because of their low cost and readily available from natural resources and acts as a reinforcing material for the polymer composites. Jute is the most widely used natural fibers among the various fibers due to its superior characteristics. Composite materials are made with different materials that are physically and chemically different alienated by interfaces. In this work, epoxy and polyester hybrid composites reinforced with jute and glass fiber were fabricated by hydraulic press method and their tensile and impact properties were compared. The mechanical properties of jute/glass hybrid composites with different layers such as tensile strength, percentage of elongation and impact strength were evaluated using ASTM specifications. Tensile and Charpy impact test results indicated that jute/glass fiber reinforced epoxy composites have shown optimum properties than polyester composites.
Fabrication of Magnesium-Silicon Nanocomplexes by the Interaction of Polyphenylsiloxane with Magnesium Carbonate
Authors: Shapkin Nikolai , Maslova Natalia , Papynov Evgeniy , Kaminskii Vladimir , Kapustina Alevtina , Libanov Vitalii , Khal'chenko Irina
Published: September 2021

The interaction of magnesium carbonate with polyphenylsiloxane under the conditions of mechanochemical activation with subsequent heating has been investigated. Based on the TGA and DTA data, it has been shown that, upon heating up to 420°C, the reaction proceeded completely with the release of carbon dioxide. The polymer was dissolved in DMFA and purified by repeated precipitation with water. The polymer yield was 64%. The residue insoluble in organic solvents has been obtained by evaporation of an aqueous solution. The composition and structure of the synthesis products have been analyzed by means of element analysis, IR spectroscopy, and diffractometry. It has been demonstrated that the fraction soluble in DMFA had a silicon-to-magnesium ratio equal to 4.2, while the fraction isolated from water had this ratio equal to 1.0. The IR and XRD data enabled one to conclude that, regardless of the different compositions, the structures of all fractions were similar and corresponded to mesomorphic layered polymers produced by the ion exchange method.
The Effect of Airflow Speed as Cooling Media in the Hardening Process to the Hardness, Corrosion Rate and Fatigue Life of Medium Carbon Steel
Authors: Sunardi Sunardi , Lusiani Rina , Listijorini Erny , Santoso Ruddy , Saefuloh Iman
Published: September 2021

Carburizing is a method for obtaining a sturdy material surface. This hard surface is used for machine elements that intersect with other materials, so failure due to wear can be avoided. However, this increase in hardness has always been followed by decreased ductility. This condition certainly lowers the fatigue life of the material. For that, it is necessary to compromise between surface hardness and ductility. This study used AISI 1045 steel, which has a surface roughness of 0.4 and 4.7 μm with carburation media used, is a mixture of 80% coconut shell charcoal and 20% Barium carbonate. The sample was given the pack carburization treatment at 850°C and holding time for 3 hours, and then cooled in the open air. The samples were reheated at 850°C, holding time for 17 minutes, and then cooled with airflow at speeds of 10.34, 15.51, and 20.06 m/s for 30 minutes. This research shows that the surface of steel with a roughness of 0.4 μm has excellent performance with the hardness and corrosion level respectively 228.6 HV and 2.3586 mpy at cooling airflow rate of 20.06 m/s while the fatigue life of material occurs at the speed of airflow cooling 10.43 m/s.
The Effect of Impregnation Ratio on the Surface Characteristics of Gigantochloa Verticillata Bamboo-Activated Carbon
Authors: Negara Dewa Ngakan Ketut Putra , Nindhia Tjokorda Gde Tirta , Lusiana Lusiana , Widiyarta I Made , Astika I Made , Kencanawati Cokorda Istri Putri Kusuma
Published: September 2021

The activation process is the final stage in the manufacturing of activated carbon that can be carried out physically or chemically. This paper focuses on characterizing the surface properties of activated carbons from Gigantochloa verticillata bamboo that are chemically activated at 750°C under different impregnation ratios (IRs) of 1:1, 2:1, and 3:1. The activated carbons produced were denoted as IR1-AC, IR2-AC, and IR3-AC for impregnation ratios of 1:1, 2:1, and 3:1, respectively. Characterizations include TGA, SEM, and adsorption isotherm tests. The results of the research show that variation of the impregnation ratio yielded fluctuated content of proximate elements and surface properties of activated carbons. The highest fixed carbon of 75.69% and the lowest ash of 13.10% were obtained by IR2-AC. The highest surface area of 511.10 m2/g and pore volume of 0.561 cc/g was obtained by IR3-AC and IR2-AC, respectively. The activated carbon pores are distributed in micropores and mesopores areas with average pore diameters of 1.245, 2.494, and 1.984 nm for IR1-AC, IR2-AC, and IR3-AC, respectively. The existence of the pores can be found on the surface morphology of activated carbons.
Performance of Ni-Mo Sulfated Nanozirconia Catalyst for Conversion of Waste Cooking Oil into Biofuel via Hydrocracking Process
Authors: Hanifa Arniz , Nadia Asma , Saputri Wahyu Dita , Syoufian Akhmad , Wijaya Karna
Published: September 2021

The synthesis of the Ni-Mo sulfated zirconia (NiMo-SZ) catalyst and its application to convert waste cooking oil into biofuel was successfully conducted. The synthesis process was started with a sulfation process on the zirconia oxide (ZrO2) using 0.5, 1.0, and 1.5 M sulfuric acid (H2SO4) through wet impregnation to obtain sulfated zirconia (SZ). Solid SZ with the highest total acidity value was calcined at temperature 500, 550, 600, 650, and 700 °C. Solid SZ calcined with the optimum temperature was treated with Ni and Mo metals at 1%, 2%, and 3% (w/w) through a hydrothermal method. Pure ZrO2, SZ, and 1, 2, and 3 NiMo-SZ catalysts were used in the hydrocracking of used cooking oil into biofuel. The results showed that the 1.5 M SZ catalyst calcined at 500 °C had the highest acidity value of 3.8137 mmol/g. The 3-NiMo-SZ catalyst had the best activity valuing at 80.54%, while 1-NiMo-SZ produced the best selectivity in producing gasoline fraction until 73.93%.
Substantiation into Parameters of Carbon Fuel Production Technology from Brown Coal
Authors: Shustov Oleksandr , Pavlychenko Artem , Bondarenko Andrii , Bielov Oleksandr , Borysovska Olena , Abdiev Arstanbek
Published: September 2021

Technological solutions for brown coal processing, thermal influence on it at temperature change, thermo vacuum drying are analysed and qualitative and quantitative characteristics of semi – coking products are studied. The parameters of crushing and thermo vacuum drying of brown coal, heat treatment and cascade separation (electrostatic and magnetic) are substantiated. Studies on the manufacture of a pilot batch of carbon fuel with high quality characteristics are performed. Cascade treatment of heat-treated brown coal on electric and magnetic separators allowed to obtain a concentrate with ash content from 17.72 to 22.8%, volatile yield ≤ 35%, higher heat of combustion from 7256.1 to 7523.6 kcal/kg. It is determined that favourable modes of preliminary heat treatment of brown coal samples are in the temperature range of 200-400°С. The established characteristics of the obtained solid fuel correspond to the gas group of thermal coal. The obtained technological solutions for the processing of brown coal can be the basis for the manufacture of an industrial line, taking into account the thermo vacuum installation for further implementation in enterprises using carbon fuel.
Clinical and socio-demographic factors associated with electroencephalographic abnormalities in children with epilepsy
Authors: Ogoke Christian Chukwukere , Igwe Wilson Chukwuneke , Umeadi Esther Ngozi
Published: September 2021

Electroencephalography (EEG) makes critical contribution to the management of epilepsies. Few studies have examined the clinical and socio-demographic factors that are likely to predict finding an abnormal or epileptiform EEG in children with epilepsy (CWE). Knowledge of clinical variables and socio demographic factors that determine EEG abnormalities may inform careful selection of children for EEG and improve the cost-effectiveness of this investigation. Therefore, this study was carried out to assess the relationship between the occurrence of EEG abnormalities and certain factors such as age, gender, clinical neurologic state, seizure type, anti-epileptic drug therapy, activation procedure such as sleep and etiology of epilepsy in children who had EEG in Owerri, Nigeria. The clinical and EEG records of children who had EEG at a tertiary referral center over a period of two years were retrospectively reviewed. Relevant data including demographics, clinical neurologic state, seizure type, EEG findings were extracted. Statistical analysis was used to determine association between categorical variables. The variables noted to be significantly associated with abnormal EEG recordings were the presence of abnormal neurologic findings (p=0.020) and etiology of epilepsy (p=0.045). There were no significant association between abnormal EEG findings and age (p=0.680), gender (p=0.802) and seizure types (p=0.157). The clinical neurological state and etiology of epilepsy in children were significantly associated with the occurrence of abnormalities and yield of interictal scalp EEG. Children with epilepsy who are neurologically abnormal or have multiple etiological factors could be prioritized in EEG appointments in resource-poor settings. Further research in children with epilepsy is needed to confirm these findings.
A new mode of mechanical ventilation: positive + negative synchronized ventilation
Authors: Vincenzi Umberto
Published: September 2021

Often, in supporting patients suffering from severe respiratory diseases with mechanical ventilation, obstacles are encountered due to pulmonary and/or thoracic alterations, reductions in the ventilable lung parenchyma, increases in airway resistance, alterations in thoraco-pulmonary compliance, advanced age of the subjects. All this involves difficulties in finding the right ventilation parameters and an adequate driving pressure to guarantee sufficient ventilation. Therefrom, new mechanical ventilation techniques were sought that could help overcome the aforementioned obstacles. A new mode of mechanical ventilation is being presented, i.e., a Positive + Negative Synchronized Ventilation (PNSV), characterized by the association and integration of two pulmonary ventilators; one acting inside the chest with positive pressures and one externally with negative pressure. The peculiarity of this combination is the complete synchronization, which takes place with specific electronic modifications. The PNSV can be applied both in a completely non-invasive and invasive way and, therefore, be used both in acute care wards and in ICU. The most relevant effect found, due to the compensation of opposing pressures acting on the chest, is that, during the entire inspiratory act created by the ventilators, the pressure at the alveolar level is equal to zero even if adding together the two ventilators’ pressures; thus, the transpulmonary pressure is doubled. The application of this pressure for 1 hour on elderly patients suffering from severe acute respiratory failure, resulted in a significant improvement in blood gas analytical and clinical parameters without any side effects. An increased pulmonary recruitment, including posterior lung areas, and a reduction in spontaneous ventilatory rate have also been demonstrated with PNSV. This also paves the way to the search for the best ventilatory treatment in critically ill or ARDS patients. The compensation of intrathoracic pressures should also lead, although not yet proven, to an improvement in venous return, systolic and cardiac output. In the analysis of the study in which this method was applied, the total transpulmonary pressure delivered was the sum of the individual pressures applied by the two ventilators. However, this does not exclude the possibility of reducing the pressures of the two machines to modulate a lower but balanced total transpulmonary pressure within the chest.
Comparison of Intravenous versus Nebulised Lignocaine for Suppression of Haemodynamic Responses to Tracheal Intubation
Authors: Bhaskar Varun , Shetty Sumalatha R , Rajaram Prabhu , Varmudy Murali Krishna
Published: September 2021

Background:

Laryngoscopy and tracheal intubation are noxious stimuli associated with transient haemodynamic changes which can be deleterious, especially in patients with cardiovascular or intracranial disease. Different pharmacological techniques are used to suppress this response. We designed this study to evaluate whether nebulised lignocaine can attenuate haemodynamic responses to intubation.

Patients and Methods:

Forty patients were enrolled for the study and randomly allocated into one of two groups, Group LN (nebulised lignocaine) and Group LI (intravenous [IV] lignocaine). Group LN and Group LI received nebulisation respectively with 5 mL of 2% lignocaine or 5 mL of normal saline 15 min before shifting the patient to the operation theatre. General anaesthesia with endotracheal intubation was provided as per institutional protocol. Participants in Group LN received 5 mL saline intravenously while Group LI received 5 mL of 2% lignocaine IV 90 s after muscle relaxant and were intubated 90 s later. Patients were monitored for the first 10 minutes postintubation without any additional drug or any surgical stimulus.

Results:

In our study, we found a statistically significant suppression of haemodynamic responses following intubation in the nebulised lignocaine group in comparison with the IV lignocaine group.

Conclusion:

Significant attenuation of haemodynamic responses to intubation was observed with nebulised lignocaine group as compared to IV lignocaine group. We believe that nebulisation of lignocaine is a simple, cost-effective and safe procedure to attenuate haemodynamic responses to intubation. This novel technique could replace the use of other pharmacological interventions for the same purpose, thereby avoiding polypharmacy.
Lepromatous leprosy as a presenting feature of HIV
Authors: Belgaumkar Vasudha A. , Chavan Ravindranath B. , Deshmukh Nitika S. , Ponathil Abhishek P.
Published: September 2021

Various bacterial, mycobacterial and fungal opportunistic infections occur frequently in immunocompromised individuals, however, leprosy in retroviral disease is a relatively rare association. Hereby, we report a case of lepromatous leprosy that presented with clinical features mimicking other opportunistic infections and subsequently led to the diagnosis of HIV. The myriad challenges associated with the diagnosis and management of HIV–leprosy coinfection are also discussed. Thus, although uncommon, atypical cutaneous lesions in HIV-seropositive patients warrant investigation for leprosy.
Multimorbidity, Consumer-Directed Care, and Drug-Related Harm
Authors: Alderman Chris
Published: September 2021

People from developed countries around the world now routinely live into their 80s and beyond, and this is associated with a range of medical and societal challenges that must be addressed. It is relatively rare to encounter older people who are not affected by one or more chronic diseases, including conditions such as osteoarthritis, gastroesophageal reflux disease (GERD), hypertension, and depression. The concurrence of a number of medical and/or psychiatric conditions in the same patient has come to be referred to as multimorbidity, and it is a particularly familiar phenomenon observed by health care providers in settings such as the Emergency Department (ED), primary care practice, and long-term care facilities. Given that
life expectancy continues to increase, and that there is considerable further investment in research for the development of new treatments, which will achieve adoption and be promoted to consumers, it is clear that multimorbidity is likely to be a driver for problems arising from medications that are vigorously promoted to consumers.
On the impact of smart contracts on auditing
Authors:   University of Oviedo, De Andrés Javier , Lorca Pedro ,   University of Oviedo
Published: September 2021

The use of smart contracts has grown exponentially over the last few years. This is a phenomenon associated with the development of other technologies, such as the blockchain and the Internet of Things (IoT). Smart contracts run in a decentralized way on the blockchain and are self- executing. This is a source of advantages in business operations, but there are also some limitations and drawbacks. Regulatory issues are also of key importance, as the legal frameworks differ across countries. Smart contracts are likely to have an impact on external auditing, as external auditors will have to adapt their capabilities and procedures to an environment where many companies use this technology. But smart contracts may also be used to define a framework which ensures continuous audit reports and direct access of authorized stakeholders to the results of audit procedures. Conversely, internal auditing will also experiment changes, both caused by a series of new risks that will have to be adequately addressed and new tools to monitor business operations. In addition, some promising research opportunities arise, both in the IT, the Legal and the Business field.
Coupled-SEA Application to Full Vehicle with Numerical Turbulent Model Excitation for Wind Noise Improvement
Authors: Aizawa Kai , Komada Masashi , Morita Hidenori , DeJong Richard , Sorenson Steve
Published: September 2021

Wind noise is becoming a higher priority in the automotive industry. Several past studies investigated whether Statistical Energy Analysis (SEA) can be utilized to predict wind noise. Because wind noise analysis requires both radiation and transmission modeling in a wide frequency band, turbulent-structure-acoustic-coupled-SEA is being used. Past research investigated coupled-SEA’s benefit, but the model is usually simplified to enable easier consideration on the input side. However, the vehicle is composed of multiple interior parts and possible interior countermeasure consideration is needed. To enable this, at first, a more detailed coupled-SEA model is built from the acoustic-SEA model which has a larger number of degrees of freedom for the interior side. Then, the model is modified to account for sound radiation effects induced by turbulent and acoustic pressure. Another concern about utilizing the coupled-SEA to wind noise development is the estimation of the turbulent and acoustic input. Several options are available for identifying the input, such as on-road data measurement, CFD simulation, and numerical turbulent model estimation. Because the turbulent model can be helpful to consider the countermeasure direction, the turbulent model application to coupled-SEA is considered. However, an appropriate turbulent model is still unclear whereas there are many kinds of turbulent models proposed. Due to this, as the next step, this paper performs a validation study in a wind tunnel to identify the suitable turbulent model for the wind noise simulation. Lastly, the entire method is validated with on-road measurements. A detailed coupled-SEA model under appropriate turbulent model input simulates test case conditions and its prediction accuracy is discussed along with a wind noise.
High-Speed Camera based Experimental Modal Analysis for Dynamic Testing of an Automotive Coil Spring
Authors: Egner Felix Simeon , Wang Yonggang , Willems Thijs , Kirchner Matteo , Pluymers Bert , Desmet Wim , Palandri Jacopo , Reff Bjoern , Wolf-Monheim Friedrich
Published: September 2021

Experimental modal analysis (EMA) is a measurement technique to assess the dynamical properties of mechanical components and systems in various phases of their life cycle, e.g. for design, end-of-line testing and health monitoring. The most common EMA uses accelerometers, which provide high frequency acceleration measurements at a few discrete locations. However, attached accelerometers may alter the systems mass and damping properties and multiple tests are required to obtain spatially dense information. To overcome these issues, in this paper we use high-speed cameras and video processing algorithms. In fact, cameras as contact-less sensors do not modify the dynamics of the system under test. Furthermore, cameras provide full-field displacement data, allowing to obtain spatially dense transfer functions with a single excitation, which reduces the experiment duration. On the downside, camera measurements are suitable for relatively low-frequency applications only and require optical contrast on the component surface. While previous camera based research was focused on flat, plate-like components, we demonstrate the methodology on a 3D automotive coil spring. We use a stereo vision setup to measure the 3D displacement field, employing Lucas-Kanade optical flow as feature tracker. Thereby, we make use of local averaging for noise reduction. As cameras are able to capture static information the geometry of the component is obtained in addition to the modal parameters. This allows for intuitive visualization of the EMA results. For the automotive coil spring under investigation we obtain the displacement field up to 140 Hz with an estimated displacement accuracy in the range of a few micrometer. The EMA results are compared to an accelerometer based EMA highlighting the advantages of camera based EMA. Furthermore, we investigate the sensitivity of the camera based EMA with respect to excitation and environmental conditions and discuss two alternative markers to enhance image contrast.
A New Hybrid Method for Solving Inverse Heat Conduction Problems
Authors: Shahnazari M. R. , Shali F. Roohi , Saberi A. , Moosavi M. H.
Published: September 2021

Solving the inverse problems, especially in the field of heat transfer, is one of the challenges of engineering due to its importance in industrial applications. It is well-known that inverse heat conduction problems (IHCPs) are severely ill-posed, which means that small disturbances in the input may cause extremely large errors in the solution. This paper introduces an accurate method for solving inverse problems by combining Tikhonov's regularization and the genetic algorithm. Finding the regularization parameter as the decisive parameter is modelled by this method, a few sample problems were solved to investigate the efficiency and accuracy of the proposed method. A linear sum of fundamental solutions with unknown constant coefficients assumed as an approximated solution to the sample IHCP problem and collocation method is used to minimize residues in the collocation points. In this contribution, we use Morozov's discrepancy principle and Quasi-Optimality criterion for defining the objective function, which must be minimized to yield the value of the optimum regularization parameter.
Application of Compact Finite Difference Method for Solving Some Type of Fractional Derivative Equations
Authors: Molavi-Arabshahi Mahboubeh , Saeidi Zahra
Published: September 2021

In this paper, the compact finite difference scheme as unconditionally stable method is applied to some type of fractional derivative equation. We intend to solve with this scheme two kinds of a fractional derivative, first a fractional order system of Granwald-Letnikov type 1 for influenza and second fractional reaction sub diffusion equation. Also, we analyzed the stability of equilibrium points of this system. The convergence of the compact finite difference scheme in norm 2 are proved. Finally, various cases are used to test the numerical method. In comparison to other existing numerical methods, our results show that the scheme yields an accurate solution that is quick to compute.
Converting a food oven into a thermal sanitizer for Personal Protective Equipment against COVID-19: Computational Fluid Dynamics simulation
Authors: Bottani Eleonora , Montanari Roberto , Volpi Andrea , Di Maria Giulio , Solari Federico , Tebaldi Letizia
Published: September 2021

COVID-19 brought several management problems, and among these surely the topic of Personal Protective Equipment (PPE) turned out to be crucial. Indeed, in the light of mandatory measurements adopted by governments both for private individuals and companies, their demand has rapidly increased, thus generating shortages, increased waste and unbalanced prices. In response to that, many industrial fields offered their tools and know-how for trying to partly face this issue, and in this paper part of a solution of this kind is presented. Specifically, it is meant the redesign of a food oven produced by an Italian company operating in the food sector (Nilma S.p.A.) for thermal sanitization against the virus in question. In this paper, the simulation of the temperature distribution inside the chamber is simulated, with subsequent experimental validation at 95°C.
Effect of High Pressure Processing on enzymatic activity for strawberries, sour cherries and red grapes
Authors: Barreto Andres Felipe Moreno , Vignali Giuseppe , Sandei Luca
Published: September 2021

Color degradation is an important factor that affect the quality and acceptability of fruit juices and purees; several enzymes, as well as the microbial endogenous population are not only responsible for this phenomenon but for changes in flavor and texture. Traditional stabilization methods have been used to preserve these kind of products; however, there is a negative impact on vitamins and bioactive compounds composition. High Pressure Processing (HPP) is a non-thermal alternative that has been applied for the extension of shelf life of fresh products, reducing the adverse effects of classical treatments. The aim of this review is to provide a scientific base on the effect of HPP technology in terms of enzymatic inactivation (peroxidase, polyphenol oxidase, ascorbate oxidase and β-glucosidase) in comparison with a conventional pasteurization process in strawberries, sour cherries and red grapes, and to propose an optimization strategy for the operational parameters to achieve the greatest inactivation
Factores internos y externos relacionados con la ROE y ROA de bancos privados ecuatorianos por tamaño desde la dolarización
Authors: Jara Gylson , Massuh Oswaldo , Ibarra Alex , Castro José , Zurita Stalin , Mendoza Adrian
Published: September 2021

Posterior a la crisis financiera de finales de los años 90, el Ecuador evidenció una notable estabilidad económica desde la adopción del Dólar como moneda de curso legal y las políticas monetarias implementadas, además, la banca privada ecuatoriana presentó un constante crecimiento influenciado por diversos factores. Ante este contexto, la presente investigación analizó la relación que han tenido como factores internos las cuentas de bancos privados, sus indicadores de gestión, medidas de concentración en el sector bancario y como factores externos variables macroeconómicas en relación a la rentabilidad en términos de ROE y ROA de los banco privados ecuatorianos de acuerdo a su tamaño desde la dolarización instaurada en el país. Mediante regresiones econométricas con información extraída de fuentes oficiales establecida bajo la estructura de datos de panel se identificaron como factores internos relacionados con la las medidas de rentabilidad a las cuentas por pagar, las cuentas por cobrar las inversiones, índices como la capacidad comercial, la liquidez, el apalancamiento, además de la concentración de créditos y de depósitos. Entre los factores externos el PIB y el precio del  barril, de petróleo resultaron ser las variables macroeconómicas más relevantes en torno de las medidas de rentabilidad de los bancos privados.
Análisis de la Relación entre Rentabilidad y Sostenibilidad Empresarial en Empresas Peruanas
Authors: Chaihuaque Bruno
Published: September 2021

El objetivo de este artículo es analizar la relación entre la rentabilidad de las empresas peruanas incluidas en el Índice de Buen Gobierno Corporativo de la Bolsa de Valores de Lima y sus prácticas de sostenibilidad. Estudios similares se han realizados para empresas en otras latitudes, cuyos resultados han sido ambiguos debido a que no siempre se encuentra que esta relación es positiva. Para este estudio se analizaron la rentabilidad (ROA, ROE y ROCE), mientras que, para medir las prácticas de sostenibilidad el puntaje obtenido en los cuestionarios de sostenibilidad empresarial de la Superintendencia del Mercado de Valores del Perú.
Evaluación de la calidad del servicio estudiantil en la carrera de Derecho de una Institución de Educación Superior pública de Guayaquil
Authors: Fuentes Durán María José
Published: September 2021

El presente estudio se realiza con la necesidad de evaluar la calidad del servicio estudiantil en la carrera de Derecho de una Institución de Educación Superior pública de Guayaquil, debido al aumento de la deserción universitaria en los últimos años en el Ecuador; el cual puede estar vinculado con la baja calidad del servicio estudiantil. Por tal motivo, se utilizó la herramienta SERVPERF para valorar el nivel de satisfacción y experiencia mediante la estimación de la tangibilidad, fiabilidad, capacidad de respuesta, seguridad y empatía. Concluyendo en que el modelo es aplicable para la evaluación de servicios estudiantiles en Instituciones de Educación superior, en el cual mediante un análisis convergente se logró visualizar que las dimensiones que tenían más efecto sobre la satisfacción fueron la Tangibilidad y la Empatía.
ỨNG DỤNG GPS ĐỘNG VÀ MÁY TOÀN ĐẠC ĐIỆN TỬ XÂY DỰNG LƯỚI KHỐNG CHẾ PHỤC VỤ LẬP BẢN ĐỒ TRÍCH ĐO ĐỊA CHÍNH TẠI VIỆN NGHIÊN CỨU VÀ PHÁT TRIỂN, TRƯỜNG ĐẠI HỌC NÔNG LÂM, ĐẠI HỌC HUẾ
Authors:   Trường Đại học Nông Lâm, Đại học Huế, Hồ Việt Hoàng , Nguyễn Văn Bình ,   Trường Đại học Nông Lâm, Đại học Huế, Nguyễn Thành Nam ,   Trường Đại học Nông Lâm, Đại học Huế, Trần Thị Ánh Tuyết ,   Trường Đại học Nông Lâm, Đại học Huế
Published: September 2021

Nghiên cứu được thực hiện nhằm ứng dụng kết hợp công nghệ GPS động và máy toàn đạc điện tử để xây dựng lưới khống chế, tạo cơ sở thống nhất và chính xác về mặt toạ độ phục vụ công tác đo vẽ thành lập bản đồ trích đo địa chính sau thu hồi đất thuộc dự án đầu tư xây dựng đoạn Cam Lộ - La Sơn tại Viện nghiên cứu và Phát triển, Trường Đại học Nông Lâm, Đại học Huế. Từ 02 điểm địa chính cơ sở, nghiên cứu đã thiết kế lưới địa chính và lưới khống chế đo vẽ phục vụ lập bản đồ trích đo tại Viện. Việc đo lưới địa chính được thực hiện bằng máy định vị vệ tinh GPS RTK 2 tần số Trimble R4 GNSS và đo lưới khống chế đo vẽ bằng máy toàn đạc điện tử South NTS-332R4. Sau đó, số liệu đo lưới địa chính được bình sai bằng phần mềm Trimble Business Center và số liệu đo lưới khống chế đo vẽ được bình sai bằng phần mềm HHMAPS. Kết quả đánh giá độ chính xác lưới khống chế đều đảm bảo theo đúng quy phạm xây dựng bản đồ địa chính. Việc ứng dụng công nghệ GPS động kết hợp sử dụng toàn đạc đã góp phần đẩy nhanh tiến độ xây dựng lưới khống chế phục vụ lập bản đồ trích đo tại Viện Nghiên cứu và Phát triển.
NGHIÊN CỨU CHỌN CÂY TRỘI VÀ NHÂN GIỐNG KEO LAI (ACACIA HYBRID) TỪ RỪNG TRỒNG ĐƯỢC TUYỂN CHỌN TẠI TỈNH THỪA THIÊN HUẾ
Authors:   Trường Đại học Nông Lâm, Đại học Huế, Phạm Cường , Trần Thị Thúy Hằng ,   Trường Đại học Nông Lâm, Đại học Huế, Nguyễn Lan Phương ,   Trường Đại học Nông Lâm, Đại học Huế
Published: September 2021

Rừng trồng keo lai hiện nay giảm về năng suất và sản lượng do nhiều giống sử dụng lâu năm và bị thoái hóa nghiêm trọng. Nghiên cứu chọn tạo giống cây keo lai từ rừng trồng chất lượng tốt tuyển chọn ở tỉnh Thừa Thiên Huế nhằm mục tiêu chọn lọc được một số cây trội, áp dụng phương pháp trẻ hóa và giâm hom để tạo vật liệu phục vụ nhân giống đại trà đồng thời phục vụ khảo nghiệm dòng vô tính. Kết quả nghiên cứu đã đánh giá các chỉ tiêu sinh trưởng, tính toán độ vượt theo các chỉ tiêu chọn lọc để xác đinh cây keo lai trội trên hiện trường. Cây trội ở rừng trồng 5 năm tuổi phải có HVN tối thiểu 18,4 m và D1.3 đạt trên 14,2 cm; cây trội chọn trên rừng trồng 7 năm tuổi phải có HVN trên 19,3 m và D1.3 từ 24,1 cm trở lên. Áp dụng kỹ thuật cắt cành dưới tán và cắt cụt ngọn để tạo chồi cành; sau 3-5 tuần cành cắt bắt đầu nẩy chồi, bình quân các cây trội có số lượng khoảng 175,8 chồi/cây và tỷ lệ chồi tốt đạt trên 67,0%. Vị trí cành thu hái chồi và tuổi cây mẹ có ảnh hưởng khác nhau đển tỷ lệ sống hom giâm. Trong đó, hom thu từ cành dưới tán có tỷ lệ hom giâm sống đạt 72,4% và cao hơn 17,2% so với hom thu từ cắt ngọn (tỷ lệ sống 55,2%). Hom giâm thu từ cây trội keo lai 5 năm tuổi có tỷ lệ sống đạt 71,9% và chỉ đạt 51,1% đối với hom thu từ cây trội keo lai 7 năm tuổi. Tỷ lệ sống hom giâm thu từ cây trội ở mức độ thấp, dao động từ 46,9% đến 81,1% và bình quân chỉ đạt 63%. Đây là những kết quả nghiên cứu mới, có ý nghĩa khoa học và ứng dụng trong công tác chọn tạo giống từ rừng trồng.
ẢNH HƯỞNG CỦA MẬT ĐỘ TRỒNG VÀ PHÂN BÓN ĐẾN KHẢ NĂNG SINH TRƯỞNG, PHÁT TRIỂN VÀ NĂNG SUẤT CÂY HOA HƯỚNG DƯƠNG TẠI TỈNH THỪA THIÊN HUẾ
Authors:   Trường Đại học Nông Lâm, Đại học Huế, Lê Trung Hiếu , Trần Đăng Hòa ,   Trường Đại học Nông Lâm, Đại học Huế, Phan Thị Duy Thuận ,   Trường Đại học Nông Lâm, Đại học Huế, Phạm Văn Thân ,   Trường Đại học Nông Lâm, Đại học Huế, Nguyễn Văn Đức ,   Trường Đại học Nông Lâm, Đại học Huế
Published: September 2021

Sunflowers are one of the flowers chosen by many localities to grow because they both create beautiful landscapes and are also a source of raw materials for oil from the seeds. This study aims to determine the planting density and amount of fertilizers being suitable for growing, well-developed, high-yielding in Thua Thien Hue province. Research results shown that planting density and fertilization did not significantly affect the germination rate and growth time of sunflower in the winter crop season. The density did not affect the number of green leaves on the plant, the diameter of the calyx, the diameter of the flower, and the durability of flowers. At the fertilization level of 90 kg N + 60 kg P2O5 + 90 kg K2O per one hectare had the highest numbers of green leaves per plant and the diameter of calyx, flower diameter, and flower durability were highest. Planting density and fertilization had an interaction affect on the plant growth and yield. The largest stem diameter was at the planting density of 50.000 plants/ha and fertilization of 60 kg N + 90 kg P2O5 + 80 kg K2O per hectare. The treatment with the planting density of 62.500 plants/ha and fertilization of 90 kg N + 60 kg P2O5 + 90kg K2O per hectare had the highest plant height, leaf area and actual yield.
Mimetit z ložiska Ján Nepomuk pri Veľkom Poli (Slovenská republika)
Authors: Števko Martin , Toth Peter , Lednický Filip , Sejkora Jiří , Dolníček Zdeněk
Published: September 2021

A new occurrence of mimetite was recently discovered at the abandoned Ján Nepomuk Pb-Ag deposit near Veľké Pole, Žarnovica Co., Banská Bystrica Region, Slovakia. It forms light to bright yellow, prismatic crystals reaching up to 5 mm in size. Mimetite occurs in fractures and cavities of strongly altered and limonitised limestone with impregnations and relicts of primary galena and pyrite. It is associated with cerussite and calcite. The refined unit-cell parameters (for the hexagonal space group P63/m) are a 10.2437(4) Å, c 7.4437(6) Å and V 676.44(6) Å3. Except of dominant contents of Pb, As and Cl only minor amounts of Ca (up to 0.36 apfu), Al (up to 0.03 apfu), P (up to 0.03 apfu) and V (up to 0.02 apfu) were detected in four mimetite samples studied by EMPA-WDS.
Atolové granáty v bazaltových metapyroklastikách z lokality Čučma - Vincent (Slovenská republika)
Authors: Ružička Peter , Myšľan Pavol , Števko Martin , Kurylo Sergii
Published: September 2021

Atoll garnets in basalt metapyroclastics from the locality Čučma - Vincent (Slovak Republic) consist of relict cores and zonal rings. Research was focused on comparison of chemical changes in these garnet microstructures. Relict cores have composition Sps41.4-45.2Grs40.6-43.0Adr6.4-13.6 Alm1.9-6.1, inner BSE light zone in the rings has composition Grs38.2-44.9Sps39.6-43.7Alm6.3-12.4 Adr6.5-9.6 and outer BSE dark zone in the rings has composition Sps34.3-40.3Grs33.3-38.3Adr8.5-17.3 Alm12.7-17.1. The highest content of Mn2+ in the atoll garnets was observed in the relict cores (1.21 - 1.33 apfu) and subsequent decreasing trend in contents of Mn2+ from the inner parts of the rings (BSE dark zone; 1.16 - 1.29 apfu) to their edge (BSE light zone; 1.02 -1.20 apfu) is present. The opposite trend was observed for Fe2+ content. Inner parts of the garnets are replaced by actinolite and calcite with slightly higher content of Mn (Act up to 0.07 apfu; Cal up to 0.02 apfu). Matrix of basalt metapyroclastics was primarily formed by hedenbergite which was later replaced by actinolite.
New data on sulphosalts from hydrothermal siderite-type veins in the Spišsko-gemerské rudohorie Mts. (eastern Slovakia): 1. Nuffieldite and aikinite from Slovinky-Došťavná vein
Authors: Števko Martin , Sejkora Jiří , Dojčanský Ľudovít
Published: September 2021

A new occurrence of nuffieldite was recently discovered in a siderite-type hydrothermal vein with sulphides in Došťavná near Slovinky, Spišsko-gemerské rudohorie Mts., Spišská Nová Ves Co., Košice Region, Slovakia. It forms lead-gray acicular crystals reaching up to 1 cm in size or aggregates up to 2.5 cm, which are enclosed in quartz-siderite matrix together with chalcopyrite, pyrite, tourmaline and chlorite. Nuffieldite is frequently replaced by minor aikinite, galena and native bismuth. The refined unit-cell parameters of nuffieldite (for the orthorhombic space group Pbnm) are: a 14.5313(16) Å, b 21.454(2) Å, c 4.0500(6) Å and V 1262.58(19) Å3. The average (n=145 analyses) empirical formula of nuffieldite from Slovinky-Došťavná based on Pb+Bi+Sb = 5 apfu is corresponding to Cu1.30Pb2.00Bi2.00(Pb0.30Bi0.30 Sb0.40)1.00(S7.12Se0.03)7.15. Aikinite forms microscopic, anhedral to subhedral grains or aggregates replacing nuffieldite. The average (n=29) empirical formula of studied aikinite based on (Cu+Pb)/2+(Sb+Bi) = 8 apfu is Pb3.83Cu3.76(Bi4.12 Sb0.09)4.21(S12.40Se0.03)12.03.
Nepodceňujme mikrobiální precipitaci oxihydroxidů železa a manganu v životním prostředí
Authors: Matýsek Dalibor , Jirásek Jakub
Published: September 2021

Dolníček (2020) described several occurrences of bog iron (limonite), which according to his article originates in recent streams by chemical precipitation, without the important role of microorganisms on this process. However, similar occurrences of reddish or orange slime, frequently accompanied by oil-like films floating on the water, are according to many papers ascribed to the biogenic iron oxidation by bacteria. To solve the origin of such precipitates, we have sampled similar materials in four places near Ostrava - Hrabová, two close to Řepiště and Staříč, and also two sites in the vicinity of Hulín investigated by Dolníček (2020). In all cases, scanning electron microscopy of dried samples at the low vacuum (ca 50 Pa) revealed a dominant share of tubular sheaths of the Leptothrix-Sphaerotilus group of bacteria. The prevailing diameter of 1.5 to 1 μm should point to genus Leptothrix, while those with a diameter up to 2.5 μm (genus Sphaerotilus) are far less common. Spiral chains of Gallionella were recognized in all samples, as well as rare pennate diatoms. Space between bacterial filaments is predominantly filled with densely stacked particles micrometer to submicrometer in size, sometimes with oval, fibrous, or tabular shape. It might be both decomposed material of previously mentioned genera and some other small-sized bacteria. Energy-dispersive spectroscopy shows dominant content of iron and oxygen, with a minor admixture of Si, Ca, Al, and P. Powder X-ray diffraction of such microbial mats is showing clastic admixtures (quartz, feldspar group minerals, illite-muscovite, and kaolinite) and two broad low-intensity peaks of ferrihydrite. Only sample D from Řepiště locality shows an absence of ferrihydrite and the presence of hematite and magnetite and/or maghemite. Therefore, we demonstrated that bacterially-induced precipitation plays a major role in the genesis of such recent bog iron occurrences and there are ways how to characterize such material by both biological and mineralogical procedures.
Agents of Deterioration of Organic Museum Objects and Their Management: A Review
Authors:   Department of Museology, Aligarh Muslim University, Aligarh- 20220, Nasrin Suboohi
Published: September 2021

Museums stored a number of objects which shows our cultural and natural heritage. These heritage materials are rich source of educative materials and are organic in nature. After a passage of time these collection become deteriorate due to some agencies. Organic objects are of immense importance, that’s why their protection and preservation are very necessary. In this article the author summarizes different agencies of deterioration and their preventive conservation treatment.
Prevalence and Psychosocial Determinants of Body Mass Index in Adult Population within a National Community Sample
Authors:   Phd Student, Psychology Department, Uskudar University, Institute of Social Sciences, Istanbul, Turkey, Kalkanlı Zeynep Gamze
Published: September 2021

Studies conducted by the World Health Organization (WHO) and Economic Development and Cooperation Organization (OECD) has shown that the prevalence of obesity is increasing worldwide and has become a serious health problem. The Body Mass Index (BMI), which is a commonly used height-weight index to classify overweight and obesity, is calculated by dividing body weight by the square of height (kg/m²). Psychological factors and sociodemographic characteristics are supposed to affect BMI under current living conditions. The aim of the study was to investigate the relationship between BMI, used in the classification of obesity, sociodemographic characteristics, and various psychological factors in adult. A total of 5,902 individuals (aged 39 and over) completed Sociodemographic Information Form, Body Mass Index Evaluation Form, and Experiences in Close Relationships Scale-Revised, Brief Symptom Inventory, Toronto Alexithymia Scale, Positive and Negative Affect Scale, Personal Well-Being Index-Adult Form. Utilizing hierarchical regression analysis, obesity and overweight were associated with educational status, number of cigarettes, number of children, negative self in both genders. Obesity and overweight were also associated withpsychiatric distress, alexithymia, and avoidant attachment scores in men. Obesity and overweight were associatedalso with alcohol use, somatization, and positive affect score in women. The results of the study reveal the importance of understanding the factors affecting obesity and addresses the problems in a multidimensional way. However, more studies are needed to better understand the factors associated with obesity in Turkey.