Theoretical Deductions Research Articles

Environmental effects of Chinese-style fiscal decentralization and the sustainability implications

Abstract Nowadays, as for the developing countries, economic growth and environmental protection serve as two main objectives to achieve sustainability. It has been widely proved that fiscal decentralization is of great use to economic growth, but its environmental effect is still inconclusive. As the complex mechanism for the impact of fiscal decentralization on environment still remains unclear, our study is making an attempt to bridge the gap by introducing a detailed theoretical analysis by making use of a utility maximization approach, and two kinds of fiscal decentralization concerning both revenue and expenditure decentralization are analyzed; besides, an empirical test is further made on their effects on environmental quality and two types of regulations (that is, fiscal environmental input and environmental administrative charge). According to the results of the theoretical analysis, both of the decentralizations have positive effects on environmental improvement. The results of the empirical tests based on the panel data of 30 provinces/municipalities confirm the above theoretical deductions, as well as the following conclusions could also be derived. First of all, the fiscal decentralization has a positive regulatory effect on the environmental regulations mentioned above, which indicates there is synergy between the two kinds of policy tools. Secondly, the empirical results determine a threshold effect of fiscal decentralization on environment. Lastly, compared with expenditure decentralization, the fiscal revenue decentralization proves to be more effective for environmental improvement. Based on these conclusions, it is recommended that the central government should strengthen both environmental management and fiscal decentralization systems so as to achieve a win-win situation for economic growth and environmental protection. Particularly, in order to maximize its potential, we propose that priority be given to fiscal revenue decentralization.

Reduced Carboxylate Graphene Oxide based Field Effect Transistor as Pb2+ Aptamer Sensor.

Aptamer functionalized graphene field effect transistor (apta-GFET) is a versatile bio-sensing platform. However, the chemical inertness of graphene is still an obstacle for its large-scale applications and commercialization. In this work, reduced carboxyl-graphene oxide (rGO-COOH) is studied as a self-activated channel material in the screen-printed apta-GFETs for the first time. Examinations are carefully executed using lead-specific-aptamer as a proof-of-concept to demonstrate its functions in accommodating aptamer bio-probes and promoting the sensing reaction. The graphene-state, few-layer nano-structure, plenty of oxygen-containing groups and enhanced LSA immobilization of the rGO-COOH channel film are evidenced by X-ray photoelectron spectroscopy, Raman spectrum, UV-visible absorbance, atomic force microscopy and scanning electron microscope. Based on these characterizations, as well as a site-binding model based on solution-gated field effect transistor (SgFET) working principle, theoretical deductions for rGO-COOH enhanced apta-GFETs’ response are provided. Furthermore, detections for disturbing ions and real samples demonstrate the rGO-COOH channeled apta-GFET has a good specificity, a limit-of-detection of 0.001 ppb, and is in agreement with the conventional inductively coupled plasma mass spectrometry method. In conclusion, the careful examinations demonstrate rGO-COOH is a promising candidate as a self-activated channel material because of its merits of being independent of linking reagents, free from polymer residue and compatible with rapidly developed print-electronic technology.

Influence of Orbit and System Parameters on Geosynchronous SAR Multiple-Aperture Interferometry Processing: Analysis and Validation

A geosynchronous synthetic aperture radar (GEO SAR) can achieve a shorter revisit time, a longer observation time, and a larger coverage area for the target scene compared with low earth orbit (LEO) SARs. Therefore, its combination with the multiple-aperture interferometry (MAI) technique can allow along-track deformation measurements with better performance. Nevertheless, because the orbit and system parameters determine the MAI measuring geometry, their influence on the accuracy of such deformation measurements should be extensively studied. In this paper, based on theoretical deductions and simulations, the performance of GEO SAR MAI processing in along-track deformation measurements is discussed considering the orbit and system parameters. The optimal along-track deformation accuracy (OADA) was introduced for quantitative performance evaluations. Finally, a repeat-track global navigation satellite system-based SAR MAI experiment, implemented with a transponder onboard displacement device on the ground and BeiDou-2 inclined geosynchronous orbit satellites, was conducted to verify the effectiveness of the proposed method and its validating analysis. The results suggested that the OADA could be improved by decreasing the azimuth antenna size or the ratio between the averaged velocities of beam footprint and satellite, mainly depending on the inclination, eccentricity, and look angle.

Water column impact on a rigid wall with air cavity effects

Water column impacts on a rigid wall without and with air cavity entrapment are investigated based on potential-flow theory without considering the gravity effect. A boundary element method is employed to simulate the entire hydrodynamic process, with an introduced decoupling technique of a shallow-water approximation to tackle the thin jet difficulty in impact problems. Numerical techniques to deal with processes including the cavity jet impingement and fluid immersion are also introduced. Numerical simulations are carried out for water column impact processes with cavities of different volumes, shapes, and initial pressures inside. Theoretical deductions are performed for the limiting case of impact without air cavity at the initial and steady state. From the energy point of view, an energy transfer relation is established to achieve a quantitative prediction of the maximum pressure in a deforming cavity in a general impact process. Quantitative analysis is made to assess the effects of the initial nondimensional potential energy of the cavity on the maximum cavity pressure during the impact. Interesting phenomena such as the inner jet generated away from the impact surface are observed and discussed.

Re-evaluation of the porosity measurements under different confining pressures: A better appraisal of reservoir porosity

Porosity is one of the most important rock properties in describing hydrocarbon reservoirs. Tests on core samples provide direct and representative porosity data, and the measurement of porosity at high confining pressures is recognized to correlate well with subsurface reservoir porosity. Whereas theoretical deductions of the changes and relationships of pressures, volumes, and compressibility suggest that porosity is reduced during the coring and lifting processes, the porosity measurement at elevated confining pressure does not evaluate original reservoir porosity. This theory is quantitatively validated by repeated laboratory experiments of loading and unloading on sandstone core samples. When the in situ confining pressure is approximately 30–35 MPa (∼4350–5076 psi), coring and lifting would cause a porosity reduction of approximately 1.2%–1.6%, and the porosity test under high confining stress results in further porosity loss. A revised approach in calculating reservoir porosity from cored samples is proposed and can have significant implications for reserve calculations, recovery factors, and geostatistical reservoir models. The study is important for both conventional and unconventional reservoirs because it discusses a fundamental mechanism of porosity change.

Enhancing the closed-loop stability of a high-Q polysilicon micro-hemispherical resonating gyroscope

This paper presents an enhanced stability strategy for the sense mode of a force-rebalanced closed-loop polysilicon micro-hemispherical resonating gyroscope (μHRG) with a high-Q quality-factor value (15.2k). The sense mode closed-loop control including the Coriolis force and quadrature error force rebalanced loop, respectively. Specific demodulation theoretical deductions with mode-split are performed to identify a precise linear model of the sense mode open loop. The frequency responses obtained by experimental tests show good agreement with the theoretical model. The experimental results demonstrate that a bandwidth of 10 Hz and a 0.51 Hz frequency-splitting closed loop gyroscope can be extended to 86 Hz and 3.3 Hz, from 6 Hz and 0.13 Hz in the open loop. The mode-matching (0.51 Hz frequency-splitting) gyroscope with closed loop control can achieve a scale factor of 2.25 mV/°/s with a nonlinearity of 0.087%, and a bias instability of 21.8°/hr with an angle random walk of 3.1°/√hr.

Increased expression diversity buffers the loss of adaptive potential caused by reduction of genetic diversity in new unfavourable environments

Mechanisms underlying adaptation to rapid environmental change are issues in evolutionary biology. It is widely accepted that reduction in genetic diversity when suddenly exposed to an unfavourable environment limits the adaptive potential of populations. With growing empirical evidence that expression diversity is likely to increase in the new environment, the role that expression diversity plays in adaptation needs to be theorized. Here, we first established a negative exponential relationship between expression diversity and genetic diversity using a phenomenological differential equation. We then derived a complex trade-off relationship between the changes of expression and genetic diversity, which followed a combination of exponential functions. Furthermore, we found the increase in expression diversity could buffer the loss of adaptive potential as genetic diversity decreased to a certain extent. These theoretical deductions were validated by transcriptomic data of Miscanthus lutarioriparius grown in two experimental fields and supported by good fit and random simulation. These results suggest that increased expression diversity may compensate the loss of genetic diversity and allow the populations to maintain a certain level of phenotypic variation to cope with sudden environmental change. This may buffer the quick diminishing of adaptive potential and consequently increases the change of adaptation to the new environment.

Nonprobabilistic reliability oriented topological optimization for multi-material heat-transfer structures with interval uncertainties

This study presents a nonprobabilistic reliability-based topology optimization (NRBTO) framework that combines a multi-material interpolation model and interval mathematics to achieve an optimal layout design for heat-transfer structures under unknown but bounded (UBB) uncertainties. In terms of the uncertainty quantification (UQ) issue, the interval dimension-wise method (IDWM) based on set collocation theory is first proposed to effectively determine the bounds of nodal temperature responses. For safety reasons, the interval reliability (IR) index corresponding to the thermal constraint is defined, and then a new design policy, i.e., the strategy of nonprobabilistic reliability oriented topological optimization is established. To circumvent problems of large-scale variable updating in a multi-material topology optimization procedure, theoretical deductions of the design sensitivity analysis are further given based on the adjoint-vector criterion and the chain principle. The validity and feasibility of the developed methodology are eventually demonstrated by several application examples.

Host Feasibility Investigation to Improve Robustness in Hybrid DWT+SVD Based Image Watermarking Schemes

Today, we face different approaches to enhance the robustness of image watermarking schemes. Some of them can be implemented, but others in spite of spending money, energy, and time for programming purpose would fail because of not having a strong feasibility study plan before implementation. In this paper, we try to show a rational feasibility study before implementation of an image watermarking scheme. We develop our feasibility study by proposing three types of theoretical, mathematical, and experimental deductions. Based on the theoretical deduction, it is concluded that the “S” coefficients in the second level of Singular Value Decomposition (SVD) offer high robustness to embed watermarks. To prove this, a mathematical deduction composed of two parts is presented and the same results were achieved. Finally, for experimental deduction, 60 different host images in both normal and medical images from various sizes of 256⁎256 to 1024⁎1024 were imposed to 9 common geometric and signal processing attacks and the resistances of “S” coefficients against the attacks in the first and second levels of SVD were compared. Experimental result shows significant enhancement in stability and robustness of the “S” coefficients in the second level of SVD in comparison to the first level. Consequently all theoretical, mathematical, and experimental deductions confirmed domination of the “S” coefficients in the second level of SVD than the first level. In this paper, we do not show any specific implementation for the watermarking scheme. Instead, we investigate the potential performance gains from the singular values (S), of the second level of SVD and Discrete Wavelet Transform (DWT), and prove their superiority in comparison to conventional SVD+DWT watermarking schemes.

Study of Heat Source Calibration and Modelling for Laser Welding Process

Heat source model is an important part when carrying out simulations of welding processes. The calibration process involves a great amount of numerical simulations or theoretical deductions with many simplifications. In this paper, an interaction finite element and optimization algorithm package is programmed to automatically calibrate heat source models. The results are then used to establish mathematical relationships between parameters of heat source and welding process variables. The models show that the absorption efficiency and depth of heat source are exponential functions of depth of focus and laser power, respectively while radius of heat source is determined by depth of focus quadratically.

Studies of Functional Nucleic Acids Modified Light Addressable Potentiometric Sensors: X-ray Photoelectron Spectroscopy, Biochemical Assay, and Simulation.

Functional nucleic acids (FNAs) are promising sensing elements, and extensive interests are excited to integrate FNAs with transducers for biochemical assays. However, efforts for FNAs modified light-addressable-potentiometric-sensor (FNA-LAPS) are rarely reported. LAPS is a versatile transducer with electrolyte-insulator-semiconductor (EIS) structure and can respond almost to any surface electronic deviation. Herein, organized studies for FNA-LAPS including experiments, theoretical derivations, and MEDICI (Synopsys) simulations are presented using Pb2+-DNAzyme GR-5 and Ag+-aptamer as proof-of-concepts, which are typical FNAs with distinctive sensing strategies. First, the on-LAPS occurrences of FNAs and their particular sensing actions are evidenced by tracking their X-ray photoelectron spectroscopy (XPS) core spectra of N 1s, P 2p, C 1s, Ag, etc. Then, applications of FNA-LAPS are executed by a homemade and mobile-phone controlled system, the limit-of-detection is 0.01 ppb, sensitivities are 2.86 (Pb2+) and 1.53 (Ag+) mV/log10(ppb) ( R2 = 0.98), respectively. Furthermore, a charge and resistor mechanism (C&R) is proposed to illustrate the measured LAPS responding for FNAs and their sensing behaviors (Pb2+-mediated cleavage and Ag+-mediated folding), based on carefully analyzing basic LAPS' experimental data and MEDICI calculated distributions of build-in potentials, energy-bands, carriers, etc., at the EIS microinterface (semiconductor side). Finally, demonstrations for C&R based FNA-LAPS principle are provided by the use of MEDICI, as a means to bridge experiments and theoretical deductions. In general, a cross-study for FNA-LAPS is proposed including XPS characterization, biochemistry detection, theoretical analysis, and MEDICI simulation, it is believed their powerful combination would provide an ideal workstation for analytical chemistry applications, not only the traditional determinations but also facilitations for investigating FNAs' configurational transformations.

Performance investigation on DCSFCL considering different magnetic materials

In order to protect high voltage direct current (HVDC) system from destructive consequences caused by fault current, a novel concept of HVDC system fault current limiter (DCSFCL) was proposed previously. Since DCSFCL is based on saturable core reactor theory, iron core becomes the key to the final performance of it. Therefore, three typical kinds of soft magnetic materials were chosen to find out their impact on performances of DCSFCL. Different characteristics of materials were compared and their theoretical deductions were carried out, too. In the meanwhile, 3D models applying those three materials were built separately and finite element analysis simulations were performed to compare these results and further verify the assumptions. It turns out that materials with large saturation flux density value Bs like silicon steel and short demagnetization time like ferrite might be the best choice for DCSFCL, which can be a future research direction of magnetic materials.

Generic Analytical Thrust-Force Model for Flapping Wings

The purpose of this paper is to propose a generic analytical flapping-wing cycle-average thrust-force estimation method by implementing elongated body theory into actuator disk theory. Compared with previous a flapping-wing analysis based on actuator disk theory, the proposed method relates wing geometry and kinematics directly to induced velocity, and the periodical pressure pulsation correction factor measurement for every different flapping-wing design is no longer necessary. The proposed method is much simpler than unsteady aerodynamics or computational implementations, and thus the complex multiparameter optimization can be avoided at the early design stage of flapping-wing vehicles. Theoretical deviation of the proposed thrust model is evaluated by a numerical simulation method, and a correction term is proposed. The corrected method is then validated by wind-tunnel experiments on an 850-cm-wing-span active-twisting flapping-wing model and experimental data from previous studies that were over large parameter ranges. The results suggest that the proposed method is valid for the flapping-wing cycle-average thrust estimation over a large range of variables. Theoretical deductions about the effects of dominant factors of flapping-wing propulsion behavior and application of the present method in both passive- and active-twisting flapping-wing designs are also discussed.

Knowledge Transfer, Knowledge-Based Resources, and Capabilities in E-Commerce Software Projects

Together with the recognition of successful knowledge transfer as an important growth strategy for small and medium-sized software firms, questions related to the knowledge-based resources have emerged, including what and where knowledge is and how capabilities may influence knowledge transfer in e-commerce software projects. This study provides a deeper understanding of the relevance of knowledge transfer in such projects. The research findings identify the challenges of transferring this tacit knowledge across such projects and even within the user organizations as well. In addition to the technology knowledge and the absorptive capabilities perspectives, this study considers the market knowledge and the associated marketing capabilities as the alternative input to such projects. Most importantly, it offers a clear guide to project managers in their team building and recruiting. By using rigorous theoretical deductions and empirical support from the case studies, the study provides significant research contributions to the academicians and the implications for the practitioners of software projects.

Sex-Gender-Conflicts in Aquatic Hermaphrodites: are Genes Immortal?

When the first edition of Richard Dawkin’s book The Selfish Gene was published (1976), the view that “altruistic behaviour” in animal populations is a common phenomenon was widely accepted. Dawkins questioned this interpretation and proposed his concept of the selfish (i.e., immortal) gene, which explains a number of phenomena, such as the evolution of anisogamy, or the roles of males vs. females during sexual reproduction in gonochorists (birds, mammals). In this 40th-2016-anniversary-analysis of Dawkins book I argue, based on observations on populations of “egoistic”, (hermaphroditic) freshwater leeches of the genus Erpobdella characterized by intraspecific cocoon cannibalism, that his theoretical deductions were basically correct. In addition, sex-gender-conflicts in leeches are discussed with reference to the avoidance of the female role in populations of these hermaphrodites. The idea of the “immortal (i.e., selfish) gene” is attributed to the 19th-century-work of the German zoologist August Weismann, and the “Post-Dawkinsian” concept of intragenomic conflicts is addressed.

Stable Galerkin finite‐element scheme for the simulation of problems involving conductors moving rectilinearly in magnetic fields

For the simulation of rectilinearly moving conductors across a magnetic field, the Galer-kin finite element method (GFEM) is generally employed. The inherent instability of GFEM is very often addressed by employing Streamline upwinding/Petrov-Galerkin (SU/PG) scheme. However, the SU/PG solution is known to suffer from distortion at the boundary transverse to the velocity and the remedial measures suggested in fluid dynamics literature are computationally demanding. Therefore, simple alternative schemes are essential. In an earlier effort, instead of conventional finite-difference based approach, the numerical instability was analyzed using the Z-transform. By employing the concept of pole-zero cancellation, stability of the numerical solution was achieved by a simple restatement of the input magnetic flux in terms of associated vector potential. This approach, however, is restricted for input fields, which vary only along the direction of the velocity. To overcome this, the present work proposes a novel approach in which the input field is restated as a weighted elemental average. The stability of the proposed scheme is proven analytically for both 1D and 2D cases. The error bound for the small oscillations remnant at intermittent Peclet numbers is also deduced. Using suitable numerical simulations, all the theoretical deductions are verified.

Dimmable LED Driver Based on Twin-Bus Converter and Differential-Mode Transformer

In this paper, a four-channel lighting-emitting diode (LED) driver is presented, which combines a twin-bus converter and three differential-mode transformers. In this LED driver, the twin-bus converter can achieve reduction of the voltage stress of the switch, and the differential-mode transformers can achieve current sharing. Furthermore, the twin-bus converter can provide demagnetizing paths for the differential-mode transformers. Above all, the LED strings can be easily expanded. Moreover, the LED currents can be regulated by the dimming control switch. Finally, theoretical deductions and experimental results are provided to demonstrate the effectiveness of the proposed topology.

A Nine-Switch-Converter-Based Integrated Motor Drive and Battery Charger System for EVs Using Symmetrical Six-Phase Machines

This paper presents a new configuration for integrated on-board battery chargers of electric vehicles (EVs) incorporating symmetrical six-phase machines. The configuration proposes an exclusive utilization of a nine-switch converter (NSC) along with the machine windings during both propulsion and charging of EVs. The proposed configuration has the advantage of employing a reduced number of components in both the EV (on-board) and charging station (off-board), with the privilege of avoiding machine electromagnetic torque production during charging/vehicle-to-grid (V2G) mode of operation. During charging/V2G mode, the NSC is turned into a conventional three-phase pulse width modulation rectifier and is directly connected to the three-phase mains through the machine windings. Conventional three-phase transformers can be employed for galvanic isolation. Switching between propulsion and charging modes is carried out using a simple hardware reconfiguration. Control schemes for both propulsion and charging/V2G modes are elaborated, along with the principles of operation of the NSC. Experimental results are provided to validate the theoretical deductions for the different operating modes.

Vibration mechanisms of spur gear pair in healthy and fault states

The vibration frequency components of gear system are complicated and changeful, some of those are even hard to explain. Based on the dynamic equations of a single-stage gear pair and some reasonable simplifications, frequency responses of the gear pair in healthy state and those suffering from different faults are analyzed, respectively. The excitation sources of vibration frequency components such as rotational frequency harmonics, mesh frequency harmonics, modulation sidebands and resonance frequency bands are investigated accordingly. The causes of the asymmetrical modulation sidebands around the mesh frequency harmonics, which are commonly appeared in the vibration spectrum of gear system, are explained. The effectiveness of the theoretical deductions is confirmed by dynamic simulations and experimental results.

Non‐isolated large step‐down voltage conversion ratio converter with non‐pulsating output current

SummaryA non‐isolated dual half‐bridge large step‐down voltage conversion ratio converter with non‐pulsating output current, utilizing one coupled inductor, one energy‐transferring capacitor, and one output inductor, is presented herein. The coupled inductor is connected between the input voltage and the output inductor and plays a role to step down the input voltage. Furthermore, the output inductor is used not only to further step down the voltage but also to provide a non‐pulsating output current. Moreover, the proposed converter can achieve zero‐voltage switching. In this study, detailed theoretical deductions and some experimental results of a prototype with 48 V input voltage, 3.3 V output voltage, and 10 A output current are provided to demonstrate the feasibility and effectiveness of the proposed converter. Copyright © 2015 John Wiley & Sons, Ltd.