Optimal Design of Magnetic Torque for a Hydraulic-Magnetic Rotary Hole Cleaning Tool in Horizontal Drilling

Summary The cleanliness of wellbore is a key factor in the drilling speed and quality of an oil field, especially in long horizontal sections of horizontal wells. Therefore, a hydraulic-magnetic rotary hole cleaning tool has been designed that does not rely on the rotary action of the drillpipe and could be used with a downhole motor to improve hole cleaning efficiency. However, the influence of magnet shape on the transmission of magnetic torque has remained unclear, such that the magnetic shaft transmission torque needed to be optimized to ensure efficient tool operation. In this study, magnetic field control equations were established in the region of the permanent magnet and air gap, and the magnetic flux distribution and magnetic torque generated between two magnetic axes in each field were calculated. Also, the influence of various magnetic field parameters on magnetic torque conduction of a strip magnet were compared and analyzed and then confirmed by comparison with experimental results. The results showed that the magnetic torque transmitted by strip magnets varied sinusoidally with magnetic axis deviation angles and that the highest torque was generated in the 12-pole model. However, the rate of increase in magnetic torque with magnet thickness was opposite to that of tile magnets, increasing with increasing magnet thickness. Magnetic torque variation with covered area was specific in the 6-pole model, showing a tendency of increasing and then decreasing. When magnet thickness was 12 mm and magnet coverage area in the effective cross section of the tool was 80%, the highest magnetic torque/unit volume of magnet was generated for achieving economic optimization. The results led to conclusions that, by solving the regional magnetic field, the magnetic torque change characteristics during movement of the magnetic drive mechanism of the hydraulic-magnetic rotary hole cleaning tool were simulated successfully and that these results could be used as an optimization analysis method for the magnetic drive mechanism of such tools.

Desain Koalisi Permanen Partai Politik dalam Sistem Pemerintahan Indonesia

The pattern of political party coalitions that fluctuate ahead of the general election indicates that the coalitions are not built based on substantial interests but pragmatic interests. As a result, the status of each party becomes unclear, which one acts on the side of the government and which one acts as the opposition. This study aims to discuss the options of permanent coalition patterns that can be applied. The research problem of this study was “What is the permanent coalition design that can be applied in the Indonesian government system?”. This study used normative legal research with statutory, conceptual, and case-study approaches. The results indicated that a permanent coalition is needed to strengthen the coalition pattern of political parties as a support for the Indonesian government system. The permanent coalition design that can be applied is a two-pole model, in which there will only two coalition groups of political parties: parties supporting the government and parties opposing the government. This two-pole model can be balanced in terms of the power between a coalition of government parties and a coalition of opposition parties. Another design that can be adopted is the coalitions which are established based on the similarity of the ideology of each political party.

Optimal Design of Double-Pole Magnetization BLDC Motor and Comparison with Single-Pole Magnetization BLDC Motor in Terms of Electromagnetic Performance

This study presents an optimal double-pole magnetization brushless DC (BLDC) motor design, compared to a single-pole magnetization BLDC motor in terms of electromagnetic performance. Initially, a double-pole model is selected based on the permanent magnet (PM) of the single-pole model. The pole separation space, which is generated in the magnetization process of the double-pole PM, is selected based on the pole space of the single-pole model. Moreover, the PM offset is selected considering the PM volume of the single-pole model. Further, an optimal model is selected using the multiple response optimal method, which is a type of response surface methodology (RSM). The objective of the optimal design is to maintain the back EMF and decrease the cogging torque; the design variables include the pole separation space and PM offset. The experimental points of the initial model are designed using the central composite method (CCD). Finally, the optimization is verified by comparing the experimental and analysis results of the single-pole model with the analysis results of the optimal model.

Doubly Cabibbo-suppressed decays of antitriplet charmed baryons

Doubly Cabibbo-suppressed (DCS) nonleptonic weak decays of antitriplet charmed baryons are studied systematically in this work. The factorizable and nonfactorizable contributions can be classified explicitly in the topological-diagram approach and treated separately. In particular, the evaluation of nonfactorizable terms is based on the pole model in conjunction with current algebra. All three types of relevant non- perturbative parameters contributing factorizable and nonfactorizable terms are estimated in the MIT bag model. Branching fractions of all the DCS decays are predicted to be of order 10−4 ∼ 10−6. In particular, we find that the three modes $$ {\Xi}_c^{+}\to {\Sigma}^{+}{K}^0,{\Sigma}^0{K}^{+} $$ Ξ c + → Σ + K 0 , Σ 0 K + and $$ {\Xi}_c^0\to {\Sigma}^{-}{K}^{+} $$ Ξ c 0 → Σ − K + are as large as (1 ∼ 2) × 10−4, which are the most promising DCS channels to be measured. We also point out that the two DCS modes $$ {\Xi}_c^{+}\to {\Sigma}^{+}{K}^0 $$ Ξ c + → Σ + K 0 and $$ {\Xi}_c^0\to {\Sigma}^0{K}^0 $$ Ξ c 0 → Σ 0 K 0 are possible to be distinguished from $$ {\Xi}_c^{+}\to {\Sigma}^{+}{K}_S $$ Ξ c + → Σ + K S and $$ {\Xi}_c^0\to {\Sigma}^0{K}_S $$ Ξ c 0 → Σ 0 K S . The decay asymmetries for all the channels with a kaon in their final states are found to be large in magnitude and negative in sign.

Angular distribution and asymmetries in the decay of the polarized charmed baryon Λc+ → K−Δ++ → K−pπ+

Angular distribution of the final particles in the decay [Formula: see text] of the polarized charmed baryon is discussed. Asymmetries are proposed that allow for determination of the components of the [Formula: see text] polarization vector. The precession angle of the polarization in the process of baryon channeling in a bent crystal is directly related to these asymmetries. The decay rate and asymmetry parameter for the [Formula: see text] decay are calculated in the pole model and compared with experiment.

Finnish Secondary Students’ Mental Models of Magnetism

We examined Finnish lower secondary students’ mental models of magnetism through their drawings, written explanations and interviews. Secondary students in Finland (N=12) engaged in six lessons designed specifically to target three key concepts in understanding magnetism: structure and organization (magnetic domains), magnetic fields and magnetic interactions. We describe how, with a finite number of key concepts introduced, students reflected upon and revised their mental models of magnetism and magnetic interactions towards more sophisticated and normative scientific views. We found two new categories of students’ models: the pole model and pole/field model. The critical moments in evolving the models happened during the investigations regarding understanding magnetic fields and magnetic internal structure. This article gives an example for teachers and researchers of how to follow students’ development of mental models in science.

Pole models of decay of natural radioactive carbon as dose-forming nuclide

The article presents the pole model of radiocarbon decay process. When using this model it is assumed that there is a pair bond in the form of an individual pole axis between proton and electron. This bond can change the tilt angle relative to the generalized axis, with increasing energy. Increase of the tilt angle of the pole axis is accompanied by increase of its energy, this process is interrelated with energy state of the paired electron. With increasing energy of the paired bond the energy of the electron decreases and it occupies the energy level located closer to the nucleus. At critical increase of energy of the pole axis it will deflect to the maximum angle, the electron takes the position located in the maximum proximity to the nucleus, which leads to the connection with the paired proton and formation of the neutron. The analysis of the decay process illustration is carried out. This article describes the β-decay process using pole models.

Elastic and diffractive scatterings in the LHC era

We review the elastic and diffractive scatterings of protons (called also the “forward physics”) with emphasis on the LHC data, especially those deviating from the expectations based on extrapolations from earlier measurements at the ISR and Fermilab and thus triggering searches for new ideas, models and theories. We list these new data and provide a brief introduction of available theoretical approaches, mainly those based on analyticity, crossing symmetry and unitarity, particularly the Regge pole model realizing these concepts. Fits to the data are presented and tensions between theoretical predictions and the data that may indicate the way to further progress are in the focus of our paper.