bluuebunny/crossref_metadata_2025 huggingface dataset:
BIOSOCIAL DIVERSITY OF SCOTS PINE (PINUS SYLVESTRIS L.) IN A TREE STAND
IN RELATION TO CHOSEN HYDRAULIC CONDUCTIVITY INDICATORS OF THE STEM
Authors: Jelonek Tomasz , Pazdrowski Witold , Kopaczyk Joanna , Arasimowicz-Jelonek Magdalena , Tomczak Arkadiusz
Published: July 2021

The research focused in determining the lignification indicator of fresh needled springs and the mass of fresh needles in reference to the lignin content in tracheid walls of peripheral area of the stem (MFT/LC and MFN/LC) of Scots pine differentiated as far as its biosocial position within the community expressed by Kraft’s classification. The material for the analysis came from mature pine stands growing on North European Plain, on the territory of Poland. Chemical and structural analyses of wood encompassed the area of mature sapwood, i.e. thickness of the last 10 annual rings located at 1.3 m (DBH). It seems that the noticed differences values of both indicators (MFT/LC and MFN/LC) in pines belonging to the first three Kraft’s biological classes are connected with physiological, physical and structural conditionings of water transport with minerals in xylem and are closely connected with competition for sunlight, water, nutrients and living space.
DATA MINING AND ITS IMPACT ON MARKETING COMMUNICATION – CASE: HEAT-TREATED BIRCH WOOD
Authors: Dudík Roman , Borůvka Vlastimil , Riedl Marcel , Holeček Tomáš
Published: July 2021

The article presents the results of a marketing survey in the area of customer preferences in the case of different degrees of heat-treated solid wood and birch veneer. Part of the marketing survey was a questionnaire survey, where the respondents, as potential customers, expressed their preferences for individual samples which, at first glance, differed in colour due to the different degrees of heat treatment. The result of the research is a clear preference for the heat-treated samples compared to the reference sample without heat treatment. A more detailed secondary analysis of the data from the questionnaire survey was performed with regard to the gender, age and education of the respondents. Here, too, it is possible to conclude a clear preference for heat-treated samples for these groups of respondents. The article also analyses the possibilities of the marketing strategy with a focus on marketing communication, especially in relation
to wood processors and producers.
EFFECT OF DIFFERENT WOOD DOWELS ON MECHANICAL PROPERTIES OF TRIANGULAR GIRDER TRUSSES
Authors: Zhang Liuliu , Chang Cheng , Yang Shuming
Published: July 2021

Static load tests were carried out on three kinds of triangular girder trusses with different diameter wood dowels, and the effects of that on the structure of girder trusses were discussed. It was found that there was a good synergy between the wood dowels and the girder trusses. Among the triangular girder trusses with different diameters, the 16 mm diameters had the best energy dissipation performance increased by 184% and deformation resistance of 0.73 mm; the 20 mm diameters had the best stability performance, the better bearing capacity of 60.42 kN and deformation resistance of 0.82 mm. The bearing capacity of the double girder trusses was 2.06-2.25 times that of two single trusses, which had the ability to ‘one plus one is greater than two’.
Optimalisasi Perawatan Mesin Press dengan Metode Failure Mode Effect Analysis (FMEA)
Authors: Santoso Ribut , Lahay Idham Halid , Junus Stella , Lapai Yolanda
Published: July 2021

Sistem perawatan yang dilakukan selama ini adalah bersifat breakdown maintenance yaitu pemeliharaan yang dilakukan setelah mesin mengalami kerusakan. Sistem ini belum memberikan data akurat kapan suatu mesin atau komponen mengalami kerusakan, sehingga strategi yang tepat untuk menjaga mesin tetap beroperasi adalah menentukan interval waktu perawatan yang optimal.Hasil analisis yang dilakukan dengan menggunakan metode Failure Mode Effect Analysis (FMEA) maka didapat komponen kritis pada Mesin Screw Press yaitu Komponen Worm Screw, Besi Shaft dan Press Cage diperoleh waktu penggantian Komponen Worm Screw 32 hari, Besi Shaft 68 hari, Press Cage 48 hari pada Mesin Screw Press 1 ; untuk Mesin Screw Press 2 Komponen Worm Screw 52 hari, Besi Shaft 128 hari, Press Cage 52 hari ; untuk Mesin Screw Press 3 Komponen Worm Screw dilakukan penggantian selama 56 hari, Besi Shaft 104 hari, Press Cage 64 hari ; untuk Mesin Screw Press 4 pada Komponen Worm Screw dilakukan penggantian selama 56 hari, Besi Shaft 72 hari, Press Cage 74 hari. Untuk Mesin Screw Press 5 pada Komponen Worm Screw dilakukan penggantian selama 50 hari, Besi Shaft 80 hari, Press Cage 92 ; hari dan untuk Mesin Screw Press 6 pada Komponen Worm Screw dengan interval waktu penggantian selama 52 hari, Besi Shaft 72 hari dan Press Cage 58 hari. Kata Kunci: FMEA, MTTF, MTTR, Downtime, Age Replacement
DIGITAL MODEL OF SURVIVABILITY TO SUPPORT THE LIFE CYCLE OF BAR STRUCTURES
Authors: Доронин Сергей Владимирович , Филиппова Юлия Федоровна
Published: July 2021

Рассматриваются структура и содержание цифровых моделей живучести на примере стержневых конструкциях. Разработаны функциональная и процедурная модели анализа живучести, выполнен численный анализ повреждаемого объекта с оценкой показателей живучести. Специфической чертой цифровых моделей живучести является то, что в основу дискретизации пространства входных данных и результатов предлагаются сценарии накопления повреждений в стержневых конструкциях.

The structure and content of digital models of survivability are considered on the example of bar structures. Functional and procedural models of survivability analysis were developed, numerical analysis of the damaged object was carried out with an assessment of survivability indicators. A specific feature of digital survivability models is that scenarios of damage accumulation in bar structures are proposed as the basis for sampling the space of input data and results.
DIGITAL LOAD MODELS OF PRECISION MIRROR ANTENNA FOR INTELLIGENT SUPPORT OF THE OPERATION STAGE
Authors: Рейзмунт Елена Михайловна , Доронин Сергей Владимирович
Published: July 2021

Рассматриваются условия нагружения зеркальных антенн воздушным потоком и тепловыми воздействиями с учетом вариабельности пространственного положения конструкции. Предложена концепция построения цифровых моделей нагруженности крупногабаритной прецизионной антенны наземных систем спутниковой связи. Определены возможности их интеграции в контуры принятия решений для интеллектуальной поддержки стадии эксплуатации.

The conditions for loading reflector antennas with air flow and thermal effects are considered, taking into account the variability of the spatial position of the structure. A concept is proposed for constructing digital models of the loading of a large-sized precision antenna for ground-based satellite communication systems. Possibilities of their integration into decision-making contours for intelligent support of the operation stage have been determined.
Theoretical and Methodological Approach to the Study of Residual Value
Authors: Lyapina A. A.
Published: July 2021

The purpose of this article is to expand the understanding of the negative environmental load from production activities. It is based on the theoretical foundations relating to residual value. It also makes use of environmental and economic accounting introduced for deep analyses of hidden residual values, in particular in discussing concluding terminal costs and remedial costs in the context of dynamics of environmental sustainability. A complex understanding of the hidden residual value is suggested on macroeconomic in the capital concept and global levels. The macroeconomic measures (indicators) are considered in accounting the hidden environmental impact resulting from production activity.
Russia in the Remaking: Civilization, Technogenesis, Economy
Authors: Zotova E. S.
Published: July 2021

The article presents an overview of the plenary conference of the international scientific conference «Russia in the remaking: the Civilization, Technogenesis, the Economy» organized by laboratory of philosophy of economic together with the scientific council «Center of Social Sciences of MSU» held on December 9–11, 2020 in the online format at Faculty of Economics of Lomonosov Moscow State University. Reports that consider from various positions the state and prospects of the Russian society, the Russian economy and, broadly, the Russian civilization, were presented at the plenary session. The presented points of view allow us to take a fresh look at what's happening in the country and in the world in times of COVID-19 challenges.
SCONE: Supernova Classification with a Convolutional Neural Network
Authors: Qu Helen , Sako Masao , Möller Anais , Doux Cyrille
Published: July 2021

We present a novel method of classifying Type Ia supernovae using convolutional neural networks, a neural network framework typically used for image recognition. Our model is trained on photometric information only, eliminating the need for accurate redshift data. Photometric data is preprocessed via 2D Gaussian process regression into two-dimensional images created from flux values at each location in wavelength-time space. These “flux heatmaps” of each supernova detection, along with “uncertainty heatmaps” of the Gaussian process uncertainty, constitute the data set for our model. This preprocessing step not only smooths over irregular sampling rates between filters but also allows SCONE to be independent of the filter set on which it was trained. Our model has achieved impressive performance without redshift on the in-distribution SNIa classification problem: 99.73 ± 0.26% test accuracy with no over/underfitting on a subset of supernovae from PLAsTiCC’s unblinded test data set. We have also achieved 98.18 ± 0.3% test accuracy performing six-way classification of supernovae by type. The out-of-distribution performance does not fully match the in-distribution results, suggesting that the detailed characteristics of the training sample in comparison to the test sample have a big impact on the performance. We discuss the implication and directions for future work. All of the data processing and model code developed for this paper can be found in the SCONE software package located at github.com/helenqu/scone.
HETDEX [O iii] Emitters. I. A Spectroscopically Selected Low-redshift Population of Low-mass, Low-metallicity Galaxies
Authors: Indahl Briana , Zeimann Greg , Hill Gary J. , Bowman William P. , Ciardullo Robin , Drory Niv , Gawiser Eric , Hopp Ulrich , Janowiecki Steven , Boylan-Kolchin Michael , Mentuch Cooper Erin , Davis Dustin , Farrow Daniel , Finkelstein Steven , Gronwall Caryl , Kelz Andreas , McQuinn Kristen B. W. , Schneider Don , Tuttle Sarah E.
Published: July 2021

We assemble a sample of 17 low-metallicity (7.45 < log(O/H)+12 < 8.12) galaxies with z ≲ 0.1 found spectroscopically, without photometric preselection, in early data from the Hobby–Eberly Telescope Dark Energy Experiment. Star-forming galaxies that occupy the lowest-mass and lowest-metallicity end of the mass–metallicity relation tend to be undersampled in continuum-based surveys as their spectra are typically dominated by emission from newly forming stars. We search for galaxies with high [O iii]λ5007/[O ii]λ3727, implying highly ionized nebular emission often indicative of low-metallicity systems. With the Second Generation Low Resolution Spectrograph on the Hobby–Eberly Telescope we acquired follow-up spectra, with higher resolution and broader wavelength coverage, of each low-metallicity candidate in order to confirm the redshift, measure the Hα and [N ii] line strengths, and, in many cases, obtain deeper spectra of the blue lines. We find our galaxies are consistent with the mass–metallicity relation of typical low-mass galaxies. However, galaxies in our sample tend to have similar specific star formation rates as the incredibly rare “blueberry” galaxies found by Yang et al. We illustrate the power of spectroscopic surveys for finding low-mass and low-metallicity galaxies and reveal that we find a sample of galaxies that are a hybrid between the properties of typical dwarf galaxies and the more extreme blueberry galaxies.
Biting Pattern and Seasonality of Filariasis Vector of Mansonia spp. in Endemic Area of Banyuasin Regency, South Sumatera, Indonesia
Authors: Pratiwi Rini , Huda Adri , Ghiffari Ahmad , Anwar Chairil
Published: July 2021

The diversity and biting activity of Mansonia is important to be determined as to predict the incriminated vector and pattern the mosquito behaviour in establishing the vector control programme. The present study has been successfully conducted to investigate the prolonged biting behaviour of Mansonia spp. in two villages in Banyuasin Regency, South Sumatera Province-Indonesia, using Human Landing Collection method (HLC) in indoor and outdoor for 14 months. The result shows that there are 4956 Mansonia spp. mosquitoes collected during the study comprising 6 species: Mansonia uniformis (40.37%), Mansonia annulifera (32.04%), Mansonia indiana (19.97%), Mansonia bonneae (5.28), Mansonia dives (2.14%); and Mansonia annulata (0.18%). The further investigation confirms that Mansonia uniformis (41.254%) and Mansonia bonneae (45.490%) become the most dominant species caught in Sedang village and Muara Sugih village, respectively and find higher biting activities in outdoor than indoor with biting peaked time at approximately 18.00-19.00. However, the biting activities is also observed in daytime, indicating the behaviour change of Mansonia spp. as the nocturnal mosquitoes. Furthermore, the periods of the highest biting rates are found in April 2017 and May 2017 in Sedang village and May 2018 in Muara Sugih Village. The high period of biting activities and behaviours become the valuable information to arrange the further controlling action of filariasis transmission in Sedang and Muara Sugih Villages as the endemic area of filariasis in South Sumatera, Indonesia.
Literature Review: Menopause and Sexual Disorders
Authors: Siregar Muhammad Fidel Ganis , Azmeila S. , Sitompul A. N. R. , Siregar M. E. A. G.
Published: July 2021

Menopause is a permanent termination of the menstrual cycle caused by the loss of activity of ovarian follicles which is enforced when experiencing amenorrhea for 12 months. The mean age for women to stop menstruating was 51.5 years. The cause of menopause is a decrease in ovarian hormones. When the ovaries stop working and estrogen levels drop, a woman will experience several complaints such as changes in menstrual patterns, vasomotor, somatic, and psychological complaints, sleep disorders, sexual disorders, urogenital disorders, osteoporosis, and cardiovascular disease.

Physical, psychological, social and cultural factors are factors that influence women’s sexual function. The ageing process is known to increase the prevalence of sexual dysfunction. Female sexual dysfunction prevalence is quite high, range from 38-85.2%. Sexual disorders can take many forms and clinical symptoms.
Circulating estrogen levels have been shown to influence sexual desire, activity, experiences, and problems in sexually active postmenopausal women. Deficiency of estrogen will cause vaginal atrophy which can affect sexual dysfunction. Many factors influence sexual dysfunction, both biological and psychological, in postmenopausal women. The goal of managing sexual disorders in postmenopausal women is to maintain age-related function. Vulvovaginal complaints should be managed individualized and depends on the severity of symptoms, medical history and lifestyle of the patient.
Comparison of Brain-derived Neurotrophic Factor Level in Depressed Patients Treated with Fluoxetine and Sertraline
Authors: Lisal Sonny Teddy , Fattah Nur Aeni M. A. , Indah Rahmawati Nur , Syamsuddin Saidah
Published: July 2021

Background: The Brain-Derived NeurotrophicFactor (BDNF) is the main neuronal growth factor in the brain that regulates neurogenesis, neuronal maturity, synaptic formation and plasticity. Studies showed BDNF level decreased in depression and the administration of anti depressant drugs increased BDNF level. In this study, we used fluoxetine and sertraline, which are Selective Serotonin Reuptake Inhibitor (SSRI) but had a different mechanism in influencing the BDNF levels. The purpose of this study was to compare the effect of fluoxetine and sertraline administration tothe BDNF level in depressed subjects. This study was conducted at Wahidin Sudirohusodo Hospital, Makassar, Indonesia and its affiliates from January to February 2019. Twenty outpatient subjects were diagnosed with depression based on DSM-V. The subjects were either antidepressant naïve, or dropping out of antidepressant therapy for at least 3 months since the last administration. Blood samples from each subject were taken by consecutive sampling, and BDNF levels were analyzed before and after administration of fluoxetine and sertraline for six weeks. Also, Hamilton Depression Rating Scale (HDRS) scores are measured before and after administration.
The BDNF serum was significantly increased by 100.6% (p<0,001) from the baseline level in the fluoxetine group and 75.4% in the sertraline group. HDRS score was decreased by39.5%  (p<0,001) in the fluoxetine group and 30.1% in the sertraline group after six weeks of administration. This study suggests that fluoxetine was superior to sertraline in increasing the BDNF level in depression.
Investir dans la dette des marchés émergents
Authors: Elbaz Joan , Strigo Sergei
Published: July 2021

Depuis 2008, la dette des pays riches connaît des rendements faibles, voire négatifs, et leur croissance économique est faible. En revanche, les rendements de la dette des pays émergents sont restés positifs, voire élevés. Par ailleurs, ces pays apparaissent moins risqués, la croissance y est plus élevée et les réserves de change sont positives. Cet article situe le contexte de la dette des pays émergents dans le contexte macroéconomique et tente de comprendre quelles seront les conséquences de la crise de la Covid, puisque le FMI prévoit une croissance plus forte dans les pays émergents que dans les pays développés. Classification JEL : E06, F03, F34, H06.
L'action du Club de Paris et du G20 en matière de traitement de dette à l'heure de la Covid-19
Authors: Badirou Gafari Schwan , Bauer Arthur
Published: July 2021

La crise de liquidité liée à la pandémie de Covid-19 pourrait se transformer en crise de solvabilité, conduisant plusieurs pays à devoir restructurer leur dette publique. Nous indiquons ici que l'évolution du paysage de la dette publique des pays à faible revenu caractérisée par l'émergence de nouveaux créanciers (officiels non membres du Club de Paris ou privés) et la diversification des outils de financement renforcent le besoin de coordination. Ensuite nous rappelons le rôle du Club de Paris comme principal forum international de restructuration des dettes officielles bilatérales et ses principes de fonctionnement. Enfin, nous présentons la réponse conjointe du Club de Paris et du G20. D'une part, en réponse à la crise de liquidité, l'initiative de suspension du service de la dette représente un exemple de coordination efficace entre le Club de Paris et les créanciers émergents. D'autre part, le cadre commun adopté le 13 novembre 2020, inspiré des principes du Club de Paris, devrait permettre une coordination entre les principaux créanciers officiels bilatéraux pour les futures restructurations lorsqu'un pays fait face à une dette insoutenable. Classification JEL : E44, F21, F30, F34, F40, G00, G10, G15, G30.
Ce que les neurotechnologies soulèvent comme enjeux éthiques et légaux pour la recherche, les neuroscientifiques, les entreprises et la société
Authors: Tabouy Laure
Published: July 2021

De nombreux projets européens et internationaux visant à faire progresser la connaissance du cerveau en combinant l’expertise de la recherche en neurosciences avec celle de la recherche en informatique permettent de miniaturiser, de rendre plus efficaces et plus performantes des neurotechnologies invasives et non invasives, bien que ces dernières soient intrusives. Développées aussi bien dans des laboratoires de recherche que dans des entreprises privées, et déjà commercialisées à destination du grand public en bonne santé, la frontière entre usages médicaux et non médicaux devient très poreuse, avec des objectifs et des investissements différents. Cette accélération de ces innovations rend indispensable une réflexion sur leurs enjeux sociétaux, éthiques et juridiques. La conception de garde-fous interdisciplinaires et de systèmes d’évaluation et de suivi, et la définition d’une gouvernance adaptée aux valeurs sociologiques, éthiques et juridiques de la France et de l’Europe émergent actuellement dans le monde entier. C’est ce qu’incarnent la neuro-éthique, appelée de ses vœux par la Conseil de l’OCDE à travers sa recommandation n°0457 de 2019 sur l’innovation responsable dans les neurotechnologies, mais aussi la révision de la loi de bioéthique intervenue en 2020 et les travaux engagés par la task force depuis début 2021 pour mettre en œuvre cette recommandation.
Quand le Féminin sort de l’Ombre
Authors: Borie Gisèle
Published: July 2021

Il revient à Jung d’avoir mis en lumière le complexe d’Électre pour la petite fille, répondant ainsi à Freud et au complexe d’Œdipe. Mais rapidement, sa réflexion sur le développement féminin prend pour lui une autre voie. Avec la figure de Perséphone, il suggère une évolution du mitan de la vie qui invite à découvrir l’Ombre, source souterraine de renouvellement de l’être féminin. Mais comment ces mythes peuvent-ils être féconds sur ce sujet de nos jours ? Et comment les pistes concernant le féminin, ouvertes par Jung, trouvent-elles écho aujourd’hui dans la psychanalyse ?
A machine learning approach to enable bulk orders of critical spare-parts in the shipping industry
Authors: Anglou Fiorentia - Zoi , Ponis Stavros , Spanos Athanasios
Published: July 2021

Purpose: The main purpose of this paper is to propose a methodological approach and a decision support tool, based on prescriptive analytics, to enable bulk ordering of spare parts for shipping companies operating fleets of vessels. The developed tool utilises machine learning and operations research algorithms, to forecast and optimize bulk spare parts orders needed to cover planned maintenance requirements on an annual basis and optimize the company’s purchasing decisions.Design/methodology/approach: The proposed approach consists of three discrete methodological steps, each one supported by a decision support tool based on clustering and machine learning algorithms. In the first step, clustering is applied in order to identify high interest items. Next, a forecasting tool is developed for estimating the expected needs of the fleet and to test whether the needed quantity is influenced by the source of purchase. Finally, the selected items are cost-effectively allocated to a group of vendors. The performance of the tool is assessed by running a simulation of a bulk order process on a mixed fleet totaling 75 vessels.Findings: The overall findings and approach are quite promising Indicatively, shifting demand planning focus to critical spares, via clustering, can reduce administrative workload. Furthermore, the proposed forecasting approach results in a Mean Absolute Percentage Error of 10% for specific components, with a potential for further reduction, as data availability increases. Finally, the cost optimizer can prescribe spare part acquisition scenarios that yield a 9% overall cost reduction over the span of two years.Originality/value: By adopting the proposed approach, shipping companies have the potential to produce meaningful results ranging from soft benefits, such as the rationalization of the workload of the purchasing department and its third party collaborators to hard, quantitative benefits, such as reducing the cost of the bulk ordering process, directly affecting a company’s bottom line.
ErgoVSM: A new tool that integrates ergonomics and productivity
Authors: Dominguez-Alfaro Denisse , Mendoza-Muñoz Ismael , Navarro-González Carlos Raúl , Montoya-Reyes Mildrend Ivett , Cruz-Sotelo Samantha E. , Vargas-Bernal Olivia Yessenia
Published: July 2021

Purpose: Identifying possible ergonomic risks generated by the implementation of Lean Manufacturing in organizations. Shows a need to integrate ergonomics and productivity indicators in process analysis, thus giving place to the ErgoVSM methodology, which is VSM (Value Stream Mapping) complemented with ergonomic analysis.Design/methodology/approach: This literature review aims to refer to the methodology and instruments used for its application, as well as the benefits obtained and the challenges that arise when applying it.Findings: This article presents a review of 26 publications regarding the ErgoVSM methodology. The ErgoVSM is mainly based on the VSM methodology developed by Rother & Shook that is most applied in the healthcare sector with ergonomic analysis instruments that focus on the physical and psychosocial factors of the workers.Originality/value: The review revealed that when using ErgoVSM, processes can be improved from the ergonomic perspective without negatively affecting productivity. Even though ErgoVSM requires more time for application compared to VSM, the value of the ergonomic data for decision making in process changes justifies the extra time.
Finite element algorithms for nonlocal minimal graphs
Authors: Borthagaray Juan Pablo ,   Departamento de Matemática y Estadística del Litoral, Universidad de la República, Salto, Uruguay, Li Wenbo , Nochetto Ricardo H. ,   Department of Mathematics, University of Tennessee, Knoxville, TN 37996, USA,   Department of Mathematics and Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
Published: July 2021

We discuss computational and qualitative aspects of the fractional Plateau and the prescribed fractional mean curvature problems on bounded domains subject to exterior data being a subgraph. We recast these problems in terms of energy minimization, and we discretize the latter with piecewise linear finite elements. For the computation of the discrete solutions, we propose and study a gradient flow and a Newton scheme, and we quantify the effect of Dirichlet data truncation. We also present a wide variety of numerical experiments that illustrate qualitative and quantitative features of fractional minimal graphs and the associated discrete problems.
Un nuevo hito para el estudio de la poliorcética púnica. El acceso en codo de Son Catlar (Ciutadella, Menorca)
Authors: Prados Martínez Fernando , Jiménez Vialás Helena , Torres Gomariz Octavio
Published: July 2021

Enmarcado en un proyecto de investigación que estudia la presencia fenicio-púnica en Menorca se desarrollan intervenciones arqueológicas en el poblado de origen talayótico de Son Catlar (Ciutadella), el único de la isla que conserva el perímetro amurallado completo. En este trabajo presentamos el reciente hallazgo de un acceso en codo abierto en el frente occidental del recinto. El reconocimiento de anomalías en este sector del encintado –mediante fotografía aérea y posterior comprobación sobre el terreno–, motivó una excavación arqueológica en extensión. Se trata de un importante descubrimiento pues es la primera estructura de este tipo localizada en el contexto balear y una de las pocas intervenidas con rigor metodológico. La excavación ha permitido documentar que este acceso fue construido en el siglo III a. C., cortando el paño original, y que fue cegada poco después, tras la conquista de la isla por Q. Cecilio Metelo hacia el año 123 a. C.
Bernardino de Texeda me fecit”: Artillería virreinal del Perú a finales del siglo XVI
Authors: Oliver Laso Juan Jesús , Ramírez Pernía Abraham
Published: July 2021

Este trabajo de investigación estudia y analiza las dos piezas de artillería recuperadas en el yacimiento de la fragata Nuestra Señora de las Mercedes. Asimismo, se revisa el estado teórico de la artillería española de los siglos XVI y XVII y se realiza una aproximación a la producción artillera de la ciudad de Lima para estas centurias. Finalmente se revisa la trayectoria profesional del maestro fundidor Bernardino de Tejeda.
Optimization the Machining Parameters of Electro Chemical Discharge Machining of NiTi Shape Memory Alloys
Authors: Hammood Shahad Ali , Al-Ethari Haydar , Rahimi Abdolreza
Published: July 2021

The electrochemical discharge machining (ECDM) is a combination effect of electrochemical machining in which metal is removed through the electrochemical process and electrical discharge machining in which metal is removed by rapid current discharges between two electrodes which are separated by a dielectric liquid and subject to an electric voltage. Difficulty of machining nickel titanium alloys by conventional methods such as; the significant tool wear, the need of highly experienced operators, and an excessive degradation in the material performance due to the high thermal and mechanical effects of these methods. For these, reasons non-conventional methods such as electrical discharge machining and electro chemical machining are often used to fabricate NiTi alloys with better machining results. The experiments were conducted with various conditions of voltage (50,60,70 and 80)V, dielectric solution concentration (30 and 40% of NaOH) and nanoparticles silver, and copper content (0.5% Cu, 0.5% Ag, 0.5% Cu and Ag) in the (55% Ni-45%Ti) alloy samples. The machining experiments were designed according to Taguchi's design of experiments (L32). Grey relational analysis was used to optimize the responses of the ECDM process. Material removal rate (MRR), tool wear rate (TWR), and surface roughness (Ra) represent the response parameters for machining of the alloy samples prepared by the powder metallurgy route. To achieve the objectives of this research work MiniTab17 software was employed. The optimal conditions were: voltage of 50V, solution concentration of 40% and the sample (NiTi+0.5%Cu+0.5%Ag) have the highest effect on machining characteristics with MRR value of 0.04991mg/sec., tool wear rate value of 0.00125mg/sec., and surface roughness of 0.0117μm.
The Computational Fluid Dynamics Investigation on the Solidification of Aluminum Cast in Moulds with Different Thickness and the Influence of the Moderate Press
Authors: Ghoben Zainab Kareem , Al-Farhany Khaled , Kareem Mohammed Q.
Published: July 2021

The influence of applying an external distributed pressure along the upper surface of the molten metal (Aluminum ) during the solidification process on the temperature reduction profile was studied including the time of solidification of the cast and the phase change moving boundary location for two mould wall thicknesses (10mm and 15mm). A 3D model was built up by Solidworks and simulated by ANSYS FLUENT; each mould wall thickness was discussed for two press cases (1bar and 3bar) sequentially, comparing with no press cases. The discussion includes the ambient temperature effect, which is taken (300K then 310K), the overall cases that studied was 7 cases. The study shows a remarkable effect of press on the temperature reduction profile especially when mix with the mould thickness effect as well as the ambient temperature which has a great order in guiding the results. The results showed that the heat reduction increases by increasing the mould thickness as well as the applied pressure. Moreover, this effect will reduce the solidification time and the moving of the boundary of phase change become faster in appearance.
Simulation Upper Bound Theorem to Prediction Extrusion Load
Authors: Taher Ahmed A.
Published: July 2021

A metal extrusion was process that extrusion puncture perforate surface of material to throw and flow across outlet of die. This operation was a complex process in extrusion while penetration occurred at same time. This process can be seen in many production operations, like in forming of making portion of metal strip, and forming of extruded portion in a complex fineblanking with extrusion operation. Also exhibit the operation properties and give the method of numerical solution. So increasing load to 610KN with increased friction factor to 0.7 and increased with increasing the reduction ratio and stroke of operation. For the results and mesh distortion, with allocations of strains may be predicted. Analyzing results was submitted of metal extruded may be classified into two zones for the different lineaments deformation. moreover, energy in the zones of deformation may be classified into two parts for their different lineaments of internal zone and contact zone with the die . Fracture location has been found from simulations. Keyword Load, Extrusion, upper bound, numerical solution
Effect Multiple Addition (TiO2 and Fly Ash) on Wear Behavior and Hardness of 2024 Al Alloy
Authors: Salman Ruaa A. , Zedin Naser K.
Published: July 2021

This research is devoted to study the effect of addition (2%) TiO2 with different weight percent of fly ash particulate (0, 2, 4, 6%) to 2024 Al alloy on the wear behavior and hardness. The alloy was fabricated by the liquid metallurgy method. The results founds that the wear rate decreased from 0.55 with 0% fly ash to 0.18 at addition percentage of 6% fly ash. Also, the results reveal increasing the samples wear rate with increasing the load and loaded time. The rate of wear was decreased with increasing the sliding speed. Also, the values of hardness increased from 120VH to 160VH with rising the fly ash from 0% to 6%. Keywords: Fly Ash addition, TiO2, 2024 Al Alloy, Wear Resistance, Hardness.
Optical and Morphological Properties of Silver Nanoparticles Synthesis by Q-Switched Nd-YAG Laser
Authors: Khdr Noor Fakher , Rasheed Bassam G. , Ahmed Baida M.
Published: July 2021

Abstract. Laser ablation of a silver target immersed in distilled water utilizing Nd: YAG laser with wavelengths of 532nm,1064nm, and 1320nm was carried out to fabricate silver nanoparticles. The synthesis of Ag NPs was carried out using various laser energy (200-1000 mJ) and different pulses (200-1000 pulse). Optical properties for the Ag nanoparticles solution were tested using UV-Visible spectrum, while the morphological properties for the Ag-nanoparticles solution after deposited on glass were tested using the atomic force microscope (AFM). The results showed that the synthesis of the Ag-nanoparticles using pulsed laser ablation in liquid (PLAL) (water) gives nanoparticles with homogeneous grain distribution and uniform surface roughness. It was found that the absorption peaks of Ag NPs increase by increasing the number of pulses shoot for the same laser wavelength and laser energy, and the reported maximum value of absorption peak is 0.363 when using 1000 pulses shoot. AFM results showed that the average diameter of the Ag NPs prepared by PLAL increases with increasing the laser wavelength. However, when using laser wavelengths of 1320nm,1064nm, and 532nm, the resulted average diameter of silver nanoparticles will be 55.38nm, 34.18nm, and 30.3nm, respectively. Finally, the average surface roughness of the Ag NPs prepared by PLAL increased with increasing the laser wavelength. The obtained average surface roughness of silver nanoparticles when using wavelengths of 1320nm,1064nm, and 532nm were 2.75nm, 1.19nm, and1.06nm, respectively.
Investigations on the Nonlinear Optical Properties of Eu3+: TiO2 Nanoparticles via Z-Scan Technique
Authors: Jabbar Basma Abbas , Tahir Khawla J. , Hussein Basheer M. , Obeed H.H. , Ridha Noor J. , Alosfur Firas K. Mohamad , Madlol Rajaa A.
Published: July 2021

Europium doped Titanium dioxide (TiO2) nanoparticles were prepared by Sol-Gel technique under varying condition to investigate the effects of Eu3 + doping on the optical properties of Titanium dioxide nanoparticles. The transmittance spectrum is clearly visible at wavelengths 394nm and 416nm, and is a result of electronic transitions of energy level of the Eu3 + ions. . The obtained composites for different doping concentration were analyzed by using Energy Dispersive X-ray Spectroscopy (EDS). The linear and nonlinear optical properties of the composite were studied using the Z-scan technique, and there was an increase in the nonlinear refractive index with an increase in the concentration of the Eu+3, where it reached its highest value, which is 3.01×10-10 at doping 2.3 while the linear absorption coefficient was an inverse proportion, where the highest value was at Pure titanium and it is 1.0296951×10-5 (cm/mw).
Enhancing Thermal Properties of Steam Turbine Blades by Coating with Nanomaterials
Authors: Ugla Adnan A. , Hasan Mushtaq Ismael , Ibrahim Zainalabden A. , Kamil Dhuha J.
Published: July 2021

Heat resistant coatings are considered for the external surface Low-Pressure Steam Turbines (LPST). 410 stainless steel covered with nano heat resistant coatings consists of a heat resistant connecting layer enhanced by nanoparticles. A commercial paint was modified by using 20%wt of (titanium dioxide (TiO2) - aluminum oxide (Al2O3)) with different concentrations range (25,50,75wt% of TiO2) layers. These nano-coatings paints were airbrushed onto the surface of specimens of steam turbine blades. The test rig and experimental apparatus have been fabricated and collected to accomplish the thermal tests. The samples were subjected to heat resistance and a temperature test approximately similar to the steam turbine's operation condition temperature. The test results are used to choose the nano-coating layer with a concentration that ensures a composition's highest protective properties. The test sample with concentration (paint-(75% Al2O3+25% TiO2)) showed the highest thermal properties compares with the other cases.
Preparation of Solid-Super Acidic Catalyst with Improvement Physical Properties
Authors: Kamel Safa Abdul Salam , Al-Jendeel Haider A. , Mohammed Wadood Taher
Published: July 2021

Sulphated zirconia (SZ) is one of the most important solid acid catalysts was synthesize at different operating conditions,different calcination temperature and sulfonating time has been used. The prepared catalyst was distinguished by X-ray Diffraction (XRD), particle size and morphology of catalyst were checked by atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively, in addition to analysis by (DTA) Differential thermally and Energy Dispersive X-Ray (EDX). Finally, the N2 adsorption-desorption was used to measure the surface area (BET) and pore volume. High degree of tetragonal crystallinity was obtained 90 %, and surface area of 169 m2/g and pore volume of 0.39 cm3g-1at 600°C calcination temperature for 3 hrs and 6 hrs time of impregnation in H2SO4. nanoparticle size of sulphated zirconia was produced with an average of 73.48 nm.
An Investigation of the Fill Factor and Efficiency of Molecular Semiconductor Solar Cells
Authors: Maadhde Taif Saad Al , Jumali Mohammad Hafizuddin , Al-Agealy Hadi J.M. , Razak Fatimah Binti Abdul , Yap Chi Chin
Published: July 2021

This study investigated and calculated the fill factor and efficiency of N719 and D149 organic dyes in titanium dioxide (TiO2) solar cell systems using a current equation that we derived using a quantum transition-state theory (TST). The theory of charge transfer reactions was used to investigate the electronic current to enhance both the fill factor and efficiency of both N719/ and D149/TiO2 solar cell systems. The current calculated for Di-terabtylammoniumcis-bis (isthiocyanato) bis (2,2-bipyridyl-4,4dicarboxylato) ruthenicyanatoum (II)(N719) and 5-[[4-[4-(2,2-Diphenylethenyl) phenyl]-1,2,3-3a,4,8b-hexahydrocyclopent [b] indol-7-yl] methylene]-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)-4-oxo-3-thiazolidineacetic acid indicated that the molecules of D149, an indoline-based dye, have to be in contact with the semiconductor due to the quantum donor-acceptor scenario model. The efficiency of N719/and D149/TiO2 solar cells were significantly affected due to transition energy, which is caused by the mechanisms of the charge transfer process. Solvents; such as trifluoroethanol (C2H3F3O), propanol (C3H8O), ethanol (C2H5OH), and acetonitrile (C2H3N); were used to determine the current, fill factor, and efficiency. Coefficients of charge transfer; such as transition energy, barrier, driving force energy, current, power-conversion efficiency, fill factor (FF), and efficiency; were evaluated theoretically. The current of the N719/ system with acetonitrile and ethanol solvents was higher than current of the N719/ system with trifluoroethanol and propanol solvents. While the current of the D149/ system with trifluoroethanol and propanol solvents was higher than current of the D149/ system with acetonitrile and ethanol solvents. The current and transition energy efficiencies of both systems varied. devices were found to have the best power conversion efficiency and low transition energies while the power conversion efficiency was large for devices with sizeable current density and activity with lower transition energies. Keywords: Fill Factor, Efficiency, Molecule/Semiconductor, Solar Cells.
Effect of Cd Substitution on Structural and Optical Properties of Zn1-xCdxSe Thin Films
Authors: Kadhim Arej , Kadhim Mustafa , Hassan Haslan Abu
Published: July 2021

In this research, Zn1-xCdxSe alloys (x from 0 to 1) were synthesized by solid-state microwave (SSM) method of producing thermally evaporated thin films. The cubic structure and the elemental ratios of the films were studied using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The optical characterizations of the as-deposited film in terms of the energy band gap (Eg), photoluminescence (PL), and Raman shift spectra were conducted at the room temperature. The Eg values for the thin films from ZnSe to CdSe were 3.4 to 1.7 eV, respectively. The PL orange emission for ZnSe thin film at 565 nm, whereas 590 nm in the yellow region for CdSe thin film. From Raman shift spectra, the two longitudinal-optical phonon modes (1LO and 2LO) at 240, and 490 cm-1 are assigned for the ZnSe and CdSe thin films.
Compositional, Structural and Morphological Analyses of Bulk GeS Alloy and its Thin Films
Authors: Al-Haji Munira , Al-Haddad Raad M.S.
Published: July 2021

Bulk Germanium monosulphide (GeS) alloy was synthesized using the usual melt-quenching technique. Its grains were used as the source material to deposit thin films by vacuum thermal evaporation. Thin-films samples were doped with 1, 2, and 3 at.% indium by thermal co-evaporation and annealed in a vacuum at temperatures 373, 473 and 550 K for an hour. Compositional, structural, and morphological properties of the bulk GeS alloy and its thin films were investigated by Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) techniques. The analyses verified the stoichiometry (GeS) of the starting material in the prepared thin films. They also revealed that the thin films under study are amorphous, homogeneous, without any cracks deposited uniformly on the glass substrate with thickness 650 to 700 nm.
Production of Porous Bioactive Glass (13-93)/Poly Ethylene Glycol Composite Scaffold for Bone Tissue Defects
Authors: Dhary Zainab I. , Farid Saad B.H. , Atiyah Alaa A.
Published: July 2021

Using the sol-gel process, glass powder was made. After the preparation method of the glass powder, x-ray analytical (XRD), particle size analysis and Fourier Transform Infrared (FTIR) were performed. The particle size analysis of manufactured glass (13-93) is found to be about 2.978 μm. (XRD) mode analysis suggested that the resulting porous scaffolds were amorphous. Using the process of salt leaching to create bioactive glass scaffolds (13-93) with structural and physical properties suitable for the human trabecular bone. XRD spectroscopy, scanning electron microscopy (SEM) and FTIR after sintering at temperature 750 °C were used to investigate the microstructure and chemical bonding of the porous scaffolds. The synthesized scaffold was soaked in medium of the simulated body fluid (SBF) and examined by SEM and XRD analysis in order to evaluate bioactivity. From the SEM morphology analysis results, it was noticed that the scaffolds comprised open and interconnected pores with a porosity range of 75-78%. High bioactivity of pours scaffolds was reported to have been observed after soaking 7days in SBF media because of the formation of apatite layer on its surfaces. Keywords: bioactive glass (13-93), scaffold, salt leaching method, SBF, sol-gel.
Are tea smallholders’ farmer organisations in Sri Lanka focused towards sectoral issues? a review on present status and way forward
Authors: Mahindapala K. G. J. P.
Published: July 2021

Smallholders are the key contributors in the Sri Lankan tea industry, which brings much needed foreign income to the county. There has been ambiguity among the stakeholders about the road map to be followed by the tea farmers' organisations in Sri Lanka. This review attempt to discuss the critical issues in tea smallholding sector, the present status of Farmer Organisations (FOs) and their contribution in resolving the issues and to provide some insights on how they can be strengthened. This review is developed through the analysis of available literature and secondary data. The literature shows that FOs, in the world, has gone many miles in the paths of member empowerment, production support, processing, financing, extension service, welfare and marketing. Tea Small Holding Development Societies were formed by the government of Sri Lanka focussing on similar objectives, particularly agriculture development, marketing facilities, welfare activities and providing credits and inputs. Low productivity, low household income, poor adoption of technologies, small land size, senility of tea, poor service receiving from the state agencies, weak infrastructure facilities, labour issues and low prices for green leaf tea are the interconnected critical issues faced by the smallholders at present and which comes under the purview of the above objectives. Evidence, however, shows that tea sector farmers' organisations (Tea Smallholding Development Societies - TSDS) have not been able to achieve their expected gole. Some strategic approaches adopted by Indian Farmer Producer Companies, Japanese Agriculture Cooperatives and Kenyan Tea Development Agency such as shifting into the market orientation, value addition, product diversification, integration of services, collective approaches, strengthening of the federated structure should be considered in developing TSDS. This approach is coherent with social enterprise concepts. Non-profit organisations integrate for-profit activities to strengthen their social mission to meet the current socio-economic challenges. Thus, based on the evidence, the author believe that TSDS should be transformed as social enterprises.