191 research outputs found

    Studi Perbandingan Penggunaan Aspal Minyak Dengan Aspal Buton Lawele Pada Campuran Aspal Concrete Base Course (Ac-bc) Menggunakan Metode Marshall Test

    Full text link
      Campuran beraspal merupakan bagian perkerasan lentur  yang terletak dibagian atas atau diatas lapis poondasi. Karena letaknya diatas maka campuran beraspal harus tahan terhadap pengausan akibat beban roda kendaraan dan pengaruh lingkungan (panas matahari dan air hujan). Disamping itu, campuran aspal dituntut untuk memiliki kekuatan yang baik sehingga dapat mengeliminasi tegangan vertical. Campuran Aspal Concrete Base Coarse (AC-BC) merupakan bagian dari perkerasan lentur yang berfungsi sebagai lapis pondasi. Pada Penelitian ini di lakukan pengujian perbandingan penggunaan aspal minyak dengan aspal buton dengan menggunakan method karakteristik marshall mulai dari kepadatan, rongga dalam campuran, rongga dalam agregat, rongga terisi aspal, stabilitas marshall, stabilitas flow dan hasil bagi marshall sehingga akan diperoleh karekteristik sesuai dengan spesifikasi teknik 2010.  Dari hasil studi perbandingan campuran ac-bc, penggunaan aspal minyak, aspal buton dengan variasi kadar aspal minyak, maka diperoleh campuran yang provorsional yaitu, campuran ac-bc dengan menggunakan aspal buton 25% dari berat agregat dan campuran ac-bc dengan kadar apal minyak  5,0 %, memiliki grafik stabilitas yang hamper sama akan tetapi pada campuran tambahan lawele memiliki stabilitas flow yang relativ tinggi. Sehingga penulis menyimpulkan penggunaan tambahan asbuton memiliki keunggulan dipergunakan untuk konstruksi jalan lingkungan dan untuk pekerjaan pemeliharaan jalan lingkungan sehingga perlu dikembangkan oleh instansi pemerintah maupun swasta guna perkembangan jaringan transportasi di provinsi Gorontalo pada khususnya dan Negara Indonesia pada umumnya.      Kata Kunci : Aspal Minyak, Aspal Buton, Lawele, Marshall Test

    Effects of nonuniform incident illumination on the thermal performance of a concentrating triple junction solar cell

    Get PDF
    PublishedJournal ArticleA numerical heat transfer model was developed to investigate the temperature of a triple junction solar cell and the thermal characteristics of the airflow in a channel behind the solar cell assembly using nonuniform incident illumination. The effects of nonuniformity parameters, emissivity of the two channel walls, and Reynolds number were studied. The maximum solar cell temperature sharply increased in the presence of nonuniform light profiles, causing a drastic reduction in overall efficiency. This resulted in two possible solutions for solar cells to operate in optimum efficiency level: (i) adding new receiver plate with higher surface area or (ii) using forced cooling techniques to reduce the solar cell temperature. Thus, surface radiation exchanges inside the duct and Re significantly reduced the maximum solar cell temperature, but a conventional plain channel cooling system was inefficient for cooling the solar cell at medium concentrations when the system was subjected to a nonuniform light distribution. Nonuniformity of the incident light and surface radiation in the duct had negligible effects on the collected thermal energy. © 2014 Fahad Al-Amri and Tapas Kumar Mallick.This work was supported by King Abdulaziz City for Science and Technology in Saudi Arabia

    8-[(1E)-1-(2-Aminophenyl­iminio)eth­yl]-2-oxo-2H-chromen-7-olate

    Get PDF
    The title Schiff base, C17H14N2O3, exists as an NH tautomer with the H atom of the phenol group transferred to the imine N atom. The iminium H atom is involved in a strong intra­molecular N+—H⋯O− hydrogen bond to the phenolate O atom, forming an S(6) motif. In the crystal structure, N—H⋯O hydrogen bonds form a C(9) chain parallel to [100] and a C(11) chain parallel to [010], while C—H⋯O hydrogen bonds form a C(11) chain parallel to [010]. The combination of N—H⋯O and C—H⋯O hydrogen bonds generates R 4 3(30) rings parallel to the ab plan

    PRUNE is crucial for normal brain development and mutated in microcephaly with neurodevelopmental impairment.

    Get PDF
    PRUNE is a member of the DHH (Asp-His-His) phosphoesterase protein superfamily of molecules important for cell motility, and implicated in cancer progression. Here we investigated multiple families from Oman, India, Iran and Italy with individuals affected by a new autosomal recessive neurodevelopmental and degenerative disorder in which the cardinal features include primary microcephaly and profound global developmental delay. Our genetic studies identified biallelic mutations of PRUNE1 as responsible. Our functional assays of disease-associated variant alleles revealed impaired microtubule polymerization, as well as cell migration and proliferation properties, of mutant PRUNE. Additionally, our studies also highlight a potential new role for PRUNE during microtubule polymerization, which is essential for the cytoskeletal rearrangements that occur during cellular division and proliferation. Together these studies define PRUNE as a molecule fundamental for normal human cortical development and define cellular and clinical consequences associated with PRUNE mutation

    Speed Control of a Multi-Motor System Based on Fuzzy Neural Model Reference Method

    Full text link
    The direct-current (DC) motor has been widely utilized in many industrial applications, such as a multi-motor system, due to its excellent speed control features regardless of its greater maintenance costs. A synchronous regulator is utilized to verify the response of the speed control. The motor speed can be improved utilizing artificial intelligence techniques, for example fuzzy neural networks (FNNs). These networks can be learned and predicted, and they are useful when dealing with nonlinear systems or when severe turbulence occurs. This work aims to design an FNN based on a model reference controller for separately excited DC motor drive systems, which will be applied in a multi-machine system with two DC motors. The MATLAB/Simulink software package has been used to implement the FNMR and investigate the performance of the multi-DC motor. moreover, the online training based on the backpropagation algorithm has been utilized. The obtained results were good for improving the speed response, synchronizing the motors, and applying load during the work of the motors compared to the traditional PI control method. Finally, the multi-motor system that was controlled by the proposed method has been improved where its speed was not affected by the disturbance. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Taif University, TU: TURSP-2020/211Funding: This research was funded by Taif University, project number (TURSP-2020/211), Taif University, Taif, Saudi Arabia

    Quantum entanglement and disentanglement of multi-atom systems

    Full text link
    We present a review of recent research on quantum entanglement, with special emphasis on entanglement between single atoms, processing of an encoded entanglement and its temporary evolution. Analysis based on the density matrix formalism are described. We give a simple description of the entangling procedure and explore the role of the environment in creation of entanglement and in disentanglement of atomic systems. A particular process we will focus on is spontaneous emission, usually recognized as an irreversible loss of information and entanglement encoded in the internal states of the system. We illustrate some certain circumstances where this irreversible process can in fact induce entanglement between separated systems. We also show how spontaneous emission reveals a competition between the Bell states of a two qubit system that leads to the recently discovered "sudden" features in the temporal evolution of entanglement. An another problem illustrated in details is a deterministic preparation of atoms and atomic ensembles in long-lived stationary squeezed states and entangled cluster states. We then determine how to trigger the evolution of the stable entanglement and also address the issue of a steered evolution of entanglement between desired pairs of qubits that can be achieved simply by varying the parameters of a given system.Comment: Review articl

    Medication adherence among diabetic and hypertensive patients in Al-Qassim region of Saudi Arabia

    Get PDF
    Non-adherence to medication is often an unrecognized risk factor that contributes to failure of the therapeutic plan. The purpose of the study was to identify factors related to high, medium and low medication adherence among adult Saudi patients with hypertension and diabetes mellitus. This study is designed as a descriptive cross sectional survey and was conducted in three tertiary care hospitals of Al-Qassim province of Saudi Arabia. The data was collected using the 8-item Morisky Medication Adherence Scale (MMAS-8) and analyzed by SPSS. Three levels of adherence were considered based on the following scores: 0 to <6 (low); 6 to <8 (medium); 8 (high). Of the 396 patients interviewed, 52% reported low adherence to prescribed medication. Multinomial logistic regression analysis was conducted. Gender, age, literacy level, duration of illness and type of chronic disease were negatively associated with medication adherence. The study shows very high proportion of low and medium adherence on long term medication, which may be responsible for the failure of achieving therapeutic outcome. Further investigation is required to evaluate the applicability of MMAS-8 as a tool of measuring medication adherence among Saudi patients with chronic diseases. Adherence enhancing strategies should also be evaluated in separate patients group
    corecore