bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydro-chemical characterization of groundwater using multivariate statistics in Hawassa City, Southern Ethiopia
Authors: Alemu Getahun Getahun , Moges Awdenegest , Tekleab Sirak 
Published: October 2024

ABSTRACT

This study characterized the hydro-chemical characteristics of groundwater for assessing the possibility of managed aquifer recharge in Hawassa City. A total of 48 water samples were taken from hand-dug wells and boreholes and examined to determine the water type, critical metrics, and key determinants of water quality. Multivariate statistical techniques such as hierarchical cluster, principal component, and linear discriminant analysis were used. The samples were divided into four variable groups and four case cluster groups. The results depicted the water hardness group (C1), soil salinity group (C2), weak and strong acids forming group (C3), and pollution indicator group (C4). Four water types were identified, Na–HCO3 and Ca–Na–HCO3 (87.5%), Ca–HCO3, and Na–Cl. Na–HCO3 was the dominant in hand-dug wells than in deep boreholes, which may account for evaporation or contaminations. Seven principal components with a cumulative variance of 78.58% were also formed. The first two, hardness and salinity, contributed 25.4 and 11.4% variance, respectively. In linear discriminate analysis, three discriminate functions with eight variables were generated, namely pH, K+, Na+, Ca2+, HCO3−, Cl−, BOD5, and COD. Thus, it is revealed that the decline in water quality attributed to natural and anthropogenic causes.
Kajian Pengaruh Pack Carburizing Dengan Sumber Karbon Arang Bambu Terhadap Kekerasan dan Ketangguhan Impak Baja AISI 1040
Authors: Chiesa Alesandro , Mahjoedin Yovial , Marthiana Wenny , Ghifari  
Published: October 2024

Penelitian ini bertujuan untuk menganalisis penambahan unsur karbon memakai arang bambu sebagai bahan karbon terhadap kekerasan dan nilai impak material baja AISI 1040 melalui pack carburizing. Pada penelitian terdapat 4 kelompok spesimen uji, yaitu raw material, material dengan perlakuan pack carburizing pada temperatur 800°C, 900°C, 1000°C. Hasil pengujian kekerasan menunjukkan meningkatnya kekerasan bahan seiring peningkatan temperatur carburizing dengan kenaikan sebesar 67,32% dari raw material. Kekerasan tertiPenelitian ini bertujuan untuk menganalisis penambahan unsur karbon memakai arang bambu sebagai bahan karbon terhadap kekerasan dan nilai impak material baja AISI 1040 melalui pack carburizing. Pada penelitian terdapat 4 kelompok spesimen uji, yaitu raw material, material dengan perlakuan pack carburizing pada temperatur 800°C, 900°C, 1000°C. Hasil pengujian kekerasan menunjukkan meningkatnya kekerasan bahan seiring peningkatan temperatur carburizing dengan kenaikan sebesar 67,32% dari raw material. Kekerasan tertinggi 50,53 HRA dijumpai pada spesimen carburizing dengan suhu 1000 ºC, dan nilai kekerasan terendah pada bahan tanpa treatment (raw material) dengan nilai 30,2 HRA. Hal ini menandakan meningkatnya unsur karbon pada bagian permukaan spesimen. Hal yang sama ditunjukkan pada pengujian impak yaitu meningkatnya energi impak seiring meningkatnya suhu treatment. Raw material memiliki energi impak 93,13 Joule, sementara energi impak, berturut-turut, pada suhu 800°C sebesar 260,44 J, 900°C sebesar 279,99 J, dan 1000°C sebesar 165,91 J. Hal ini menunjukkan bahwa ketangguhan spesimen menurun pada suhu carburizing tinggi seiring dengan meningkatnya kekerasan bahannggi 50,53 HRA dijumpai pada spesimen carburizing dengan suhu 1000 ºC, dan nilai kekerasan terendah pada bahan tanpa treatment (raw material) dengan nilai 30,2 HRA. Hal ini menandakan meningkatnya unsur karbon pada bagian permukaan spesimen. Hal yang sama ditunjukkan pada pengujian impak yaitu meningkatnya energi impak seiring meningkatnya suhu treatment. Raw material memiliki energi impak 93,13 Joule, sementara energi impak, berturut-turut, pada suhu 800°C sebesar 260,44 J, 900°C sebesar 279,99 J, dan 1000°C sebesar 165,91 J. Hal ini menunjukkan bahwa ketangguhan spesimen menurun pada suhu carburizing tinggi seiring dengan meningkatnya kekerasan bahan
Analisis Variasi Waktu Tekan Terhadap Sambungan Pengelasan Rotary Friction Welding Menggunakan SEM EDX
Authors: Al Farizi Salman , Agus Fikri  , Mujirudin Mohammad , Avorizano Arry 
Published: October 2024

Rotary friction welding adalah teknik pengelasan yang memanfaatkan panas yang dihasilkan dari gesekan. Prosesnya melibatkan dua logam yang dipertemukan pada ujung-ujungnya, kemudian kedua permukaan ditekan menggunakan gaya. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh waktu tekan terhadap pembentukan senyawa intermetalik antara aluminium dan tembaga. Waktu tekan pada penyambungan aluminium dan tembaga ditetapkan sebesar 60, 120, dan 180 detik. Selanjutnya untuk mengidentifikasi distribusi dan konsentrasi senyawa intermetalik yang terbentuk pada masing-masing waktu tekan tersebut digunakan SEM-EDX. Hasil penelitian menunjukkan bahwa morfologi dan komposisi zona sambungan sangat dipengaruhi oleh waktu tekan. Tembaga berdifusi ke dalam aluminium pada waktu tekan yang lebih singkat yaitu 60 detik, menciptakan lapisan intermetalik tipis dan rata. Sebaliknya dengan waktu tekan yang lebih lama 120 dan 180 detik, maka konsentrasi tembaga di zona sambungan cenderung turun karena mekanisme self cleaning dan redistribusi material, yang menghasilkan lapisan intermetalik yang lebih tebal tetapi dengan distribusi yang tidak merata.

Rotary friction welding is a welding technique that utilizes heat generated from friction. The process involves two metals that are brought together at their ends, then both surfaces are pressed using force. The aim of this research is to determine the effect of pressing time on the formation of intermetallic compounds between aluminum and copper. The pressing time for joining aluminum and copper was set at 60, 120, and 180 seconds. Furthermore, SEM-EDX was used to identify the distribution and concentration of intermetallic compounds formed at each pressing time. The results showed that the morphology and composition of the joint zone were greatly influenced by the pressing time. Copper diffused into aluminum at a shorter pressing time of 60 seconds, creating a thin and even intermetallic layer. In contrast, with a longer pressing time of 120 and 180 seconds, the copper concentration in the joint zone tended to decrease due to the self-cleaning mechanism and material redistribution, which resulted in a thicker intermetallic layer but with an uneven distribution
Pengaruh Pendinginan terhadap Daya Keluaran dan Efisiensi Sistem Panel Surya
Authors: Efendi M Shofriyan , Rifky Rifky , Nofendri Yos , Rohman Nur 
Published: October 2024

Salah satu aplikasi energi terbarukan yang memanfaatkan energi matahari adalah panel surya atau sistem fotovoltaik. Kinerja sistem fotovoltaik dipengaruhi oleh besarnya intensitas cahaya matahari dan temperatur permukaan panel surya itu sendiri. Penelitian ini mencoba mengatasi masalah temperatur tersebut dengan membuat sistem pendingin yang dirangkai pada bagian bawah panel surya. Tujuan penelitian yang ingin dicapai adalah untuk mendapatkan daya keluaran dan efisiensi sistem fotovoltaik yang maksimal dengan memasang sistem pendingin. Sistem fotovoltaik diekspos ke arah utara sepanjang hari. Sistem fotovoltaik tanpa menggunakan sistem pendingin dan yang menggunakan sistem pendingin dioperasikan dengan waktu pengukuran parameter yang sama. Parameter yang diukur adalah intensitas cahaya, kecepatan angin, debit air, temperatur lingkungan, temperatur panel surya, temperatur pendingin, tegangan listrik dan arus listrik. Hasil dari penelitian menunjukkan bahwa daya keluaran (P_out) tanpa sistem pendingin sebesar 44,439 watt dan daya keluaran (P_out) dengan sistem pendingin sebesar 49,181 watt. Efisiensi sel surya tanpa sistem pendingin sebesar 13,541% dan sel surya dengan sistem pendingin sebesar 14,162%. . Hal ini menunjukkan bahwa sistem pendingin dapat meningkatkan kinerja sel surya.

One of the applications of renewable energy that utilizes solar energy is solar panels or photovoltaic systems. The performance of the photovoltaic system is influenced by the amount of sunlight intensity and the surface temperature of the solar panel itself. This research tries to solve the temperature problem by making a cooling system that is strung at the bottom of the solar panel. The research objectives to be achieved are to obtain the maximum output power and efficiency of the photovoltaic system by installing a cooling system. The photovoltaic system is exposed north throughout the day. Photovoltaic systems without the use of cooling systems and those using a cooling system are operated with the same parameter measurement time. The parameters measured are light intensity, wind speed, water discharge, environmental temperature, solar panel temperature, cooling temperature, electric voltage and electric current. The results of the research show that the output power (P_out) without a cooling system of 44.439 watts and an output power (P_out) with a cooling system of 49.181 watts. The efficiency of solar cells without a cooling system was 13,541% and a solar cell with a cooling system was 14,162%. . This shows that the cooling system can improve the performance of solar cells.
Radiation and thermal embrittlement of RPV steels: the links of embrittlement mechanisms, fracture modes and microcrack nucleation and propagation. Part 2. Strength and plasticity properties
Authors: Margolin B. Z. , Fomenko V. N. , Shvetsova V. A. , Yurchenko E. V. 
Published: October 2024

The uniaxial tension test results are represented over wide temperature range for smooth round bars of 2Cr–Ni–Mo–V steel and A533 steel used for RPVs of WWER and PWR types. These steels are studied in the following states: (1) the initial (as-produced) state; (2) the thermally embrittled state modelling hardening mechanism of embrittlement; (3) the thermally embrittled state modelling non-hardening mechanism of embrittlement; (4) the irradiated state. The true stress-strain curves are determined over wide temperature range that is required for calculation of the stress-and-strain fields for various specimens. The true stress-strain curves for the investigated steels in the initial and thermally embrittled states are obtained when using standard mechanical characteristics. For the irradiated steels the true stress-strain curves are obtained when using the data of the digital video recording under continuous in-testing monitoring of the cylindrical parts of tensile bars. For the irradiated materials the procedure based on standard characteristics cannot be used as it is connected with very small strain. The procedure based on the digital video recording data is verified by comparison of the stress-strain curves obtained for the initial and thermally embrittled states on the basis of the digital video recording data and standard characteristics.
ANALISIS PEMETAAN KONDISI TAMAN BACAAN MASYARAKAT (TBM) DI KOTA PEKANBARU
Authors: Sari Fadilah , Sudiar Nining , Amelia Vita 
Published: October 2024

The conditions of libraries in urban areas and universities are very different from the conditions in the Community Reading Gardens (TBM) which are currently also developing and increasing in Pekanbaru City, however amid the development of TBM in Pekanbaru City there are still many TBM that do not yet have library collection standards, facilities and infrastructure standards, personnel standards, organizational standards, and management standards. Of the 36 Community Reading Gardens (TBMs) in Pekanbaru City, it is not yet clearly known what the condition is, both the condition of the collection and the condition of the infrastructure. So it is necessary to conduct further research related to the condition of the TBM in Pekanbaru City. This research used descriptive qualitative method. Data collection was done by observation, interview and documentation. Based on the results and discussion, it is found that only 11 TBMs are active with the dominant condition of TBMs already having a vision, mission and purpose of its establishment, judging from the target of its establishment, the average TBM has not determined who is the target of the establishment of TBMs. While in terms of human resources, the average TBM already has more than 3 administrators. Overall TBMs have provided reading services and on average TBMs have provided lending services. In terms of facilities, there are still minimal TBMs that provide decent facilities for their users. Activity programs provided by TBMs vary such as reading, drawing, coloring, book review and others. While promotional activities, the average TBM already has a social media account as a promotional tool. And in terms of cooperation, all TBMs have collaborated with organizations, communities, government agencies, and others.
¿Qué hay de nuevo?
Authors: Bantar Gabriela Judith 
Published: October 2024

La presente propuesta está enfocada en la enseñanza del piano con un repertorio alojado en las músicas actuales. Considerando la composición e interpretación del instrumento, con foco en la incorporación de técnicas extendidas y la búsqueda de nuevas sonoridades, se propone una formación de intérpretes que desarrollen capacidad creativa y exploratoria desde sus inicios en el estudio del instrumento. Reconociendo la importancia de las músicas actuales de transmisión escrita, como, así también, el acceso a obras de autoría de compositoras y compositores de vanguardia, se utilizará repertorio recientemente compuesto por la brasilera Mariana Mendes.
Dynamics of Land Use and Coverage and its Impacts on the Upper Moquegua River Hydrographic Basin
Authors: Toledo Osmar Cuentas , Silva Ardemirio de Barros , Escada Maria Isabel Sobral , Toledo Maryluz Cuentas , Souza Jessica Suzarte Carvalho de , Silva Filho Aloisio Machado da 
Published: October 2024

Objective: Evaluate; identify and qualify the impacts of the dynamics of land use and coverage in the years 1973 and 2016 in the Hydrographic Basin and in the marginal strip of the Upper Moquegua River in Moquegua Peru.
Theoretical framework: In the area studied, human activities and global climate change have disturbed the balance of natural systems, causing major impacts and complex consequences on land use and cover.

Method: Digital image processing techniques and supervised classification using the maximum likelihood method were used, followed by matrix editing with refinement of the base and thematic cartography, reaching 94.4% accuracy in interpretation for the year 2016.

Result and discussion: The main changes identified regarding the dynamics of land use and coverage were similar in the basin area and in the marginal strip. An increase was noted in the urban area of the entire basin of 568.53ha (1,097.96%) and 134.86ha (1,263.33%) in the marginal strip, which may have been largely influenced by mining activity, which was not observed in 1973, but present in 2016, occupying an area of 1,092.77ha throughout the basin, with 171.99ha in the marginal strip. The areas that had the greatest reduction were those of the glacier, with 2,275.39ha (-93.33%) in the entire basin and 83.77ha (-100.00%) in the marginal strip.

Conclusion: With the results of this research, we hope to contribute to the literature related to the topic and to actions and public policies that encourage the appropriate use of land in the Upper Moquegua River Basin, especially in environmental protection areas.
Call for Papers Refugee Return
Authors: Penz Peter , Simmons Alan 
Published: October 2024

This issue of Refuge, Canada's periodical on refugees, will address the process of refugee return to their home countries. In a number of cases around the world, peace treaties and similar agreements following displacement-inducing conflicts have made this possible. Examples from the past decade are the return of Guatemalans from Mexico, of Mozambiquans from Malawi, of Chittagong hillpeople from India back to Bangladesh, and of Bosnians from other countries in Europe.
Математическое моделирование одного эффективного способа селективного забора воды из промежуточного слоя трехслойного стратифицированного водоема
Authors: И.Д. Музаев , К.С. Харебов , Н.И. Музаев 
Published: October 2024

Разработан новый эффективный способ селективного забора воды из промежу точного слоя трехслойного стратифицированного водоема. Математическим и ком пьютерным моделированием впервые в мире доказано утверждение о том, что ес ли из всех трех слоев водоема синхронно забирать воду, то поверхности раздела слоев не искривляются и в отличие от существующих способов не создаются кри тические ситуации забора воды. Доказательством эффективности разработанного способа стала возможность забирать воду из промежуточного слоя с высоким рас ходом. В промежуточном слое вода бывает холоднее и чище, чем в других слоях водоема.
The purpose of the article is to develop an effective water intake method for selective water intake from the intermediate layer of a three-layer reservoir with density stratification, where the water is colder by 8–10 ∘C compared to the temperature of the surface layer and at the same time cleaner than in the bottom layer of the reservoir. Methodology of hydrodynamics of vortex free motion of an ideal incompressible fluid is used. A spatial three-layer contact initial boundary value problem has been set and solved analytically, which mechanically and mathematically models the above-described new method of selective water intake from the intermediate layer. A set of calculation formulas for the laws of oscillation and curvature of the interface of layers is obtained. The novelty of the method relies on the fact that water from all three layers is synchronously taken through three windows arranged on the side of the reservoir so that they fit in one vertical strip symmetrically relative to the initially stationary horizontal planes of the water layers section. Computer experiments have proved that with synchronous water intake from all three windows, the interface surfaces of the layers practically retain their original horizontal positions. In this regard, it becomes possible to selectively take water from the intermediate layer through an intermediate window with a relatively high flow rate. This is the effectiveness of the proposed method of water intake from a stratified reservoir.
Приемы оптимизации алгоритмов строгого анализа связанных волн
Authors: А.И. Антонов , Г.И. Грейсух , Е.Г. Ежов 
Published: October 2024

Предложены три приема сокращения времени, необходимого для расчета одно го значения или ряда значений дифракционной эффективности, полученных с по мощью алгоритмов строгого анализа связанных волн. Это прием, использующий свойства матрицы Теплица, прием уменьшения количества переменных в функ ции коэффициентов Фурье и прием использования параллельных вычислений. На примерах задач по построению зависимостей дифракционной эффективности двухслойных двухрельефных пилообразных микроструктур с просветляющими по крытиями от угла падения излучения и температуры показано, что использование свойств матриц Теплица позволяет существенно сократить время расчета. Парал лельные вычисления также сокращают время вычислений, но при этом использу ется больше оперативной памяти.
Rigorous coupled-wave analysis is a widely used method to determine the diffraction efficiency of periodic structures. The computational complexity that arises when implementing algorithms for rigorous coupled-wave analysis is characterized by the time required for the calculation and the amount of RAM used by the computer. The calculated time, in turn, depends on the selected parameters of the number of plane waves (modes), the sum of which determines the electromagnetic field, and the number of lattice plates into which the periodic structure is divided. This paper proposes three techniques for reducing the time required to calculate a single value or series of diffraction efficiency values obtained using rigorous algorithms for coupled wave analysis. The first technique uses the properties of Toeplitz matrices, which are the matrices of Fourier coefficients when expanding the dielectric constant of each lattice plate into a series. The second technique reduces computational complexity by reducing the number of variables in the Fourier coefficient function. The third technique uses parallel computing to calculate a set of Fourier coefficient matrices and a set of diffraction efficiency values. Using examples of problems of constructing the dependences of the diffraction efficiency of two-layer double-relief sawtooth microstructures with antireflection coatings on the angle of incidence of radiation and temperature, it is shown that the use of the properties of Toeplitz matrices can significantly reduce the calculation time. The second technique insignificantly reduces the calculation time. Parallel computing significantly reduces computation time, while using more RAM. By combining the proposed techniques, a working algorithm that meets the user’s requirements for the estimated time and available RAM of the computer is proposed.
Компактная схема для моделирования динамики конкурирующих популяций на неоднородном ареале
Authors: Б.Х. Нгуен , Т.Д. Ха , В.Г. Цибулин 
Published: October 2024

Для решения задач популяционной динамики на основе уравнений реакции диффузии–адвекции, учитывающих направленную миграцию на ресурс и конкуренцию видов, предложена компактная схема метода конечных разностей с дискретизацией, использующей смещенные сетки по пространственной координате. Реализована схема метода прямых с аппроксимацией по пространству на трехточечном шаблоне и использованием интеграторов по времени высокого порядка. Проведены вычислительные эксперименты для нелинейных уравнений с переменными коэффициентами при различных граничных условиях. Представлены результаты расчетов задач с точными решениями для оценки точности и порядка аппроксимации. Продемонстрирована эффективность данной схемы для расчета динамики трех конкурирующих за неоднородный ресурс видов.
The research is aimed to describe the numerical method for studying population models based on the reaction–diffusion–advection equations with variable coefficients. It is important to analyze the impact of directed migration towards a resource on temporal-spatial competition of species. We apply a method of lines with a staggered grid for discretizing the nonlinear problems with high order accuracy on three-point stencil in spatial coordinate. To integrate in time, a high order Runge–Kutta method is used (ode89 in MATLAB). The scheme was tested using special problems allowing exact solutions. We carried out calculations of stationary distributions for species in a heterogeneous environment under various boundary conditions. Numerical estimates of accuracy orders were obtained using the given scheme and compared with the second order approximation analogue. We performed a computational experiment to assess the order of approximation with non stationary regimes using the Aitken process. Our results demonstrate the effectiveness of a compact scheme for calculating the dynamics of three species competing in a heterogeneous habitat.