Principal Point Research Articles

Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I

The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.

Efficient match pair selection for matching large-scale oblique UAV images using spatial priors

ABSTRACT Image matching is critical for photorealistic 3D reconstruction based on oblique images. An efficient match pair selection methodology for matching large-scale oblique UAV images is proposed in this paper. The proposed methodology effectively uses existing geospatial data and prior knowledge about data acquisition to generate precise match pairs. First, the principal point of each image is directly georeferenced. The direct georeferencing is based on a novel new DEM-aided direct georeferencing algorithm which employs an iterative binary search in the elevation domain. Second, a terrain-adaptive search radius is calculated for each image based on the calculated ground points, POS data, and prior knowledge. Finally, initial match pairs are generated based on a camera-oriented approach. The camera-oriented approach generates match pairs using k nearest neighbours (knn) search and prior knowledge. False connections in the initial match pairs are filtered using geometrical constraints. A limited number of match pairs are kept to reduce the redundancy of the generated match graph. The proposed methodology is tested on a dataset containing 28,560 images. The experimental results show that the precision of the generated match pairs is 99.99%. An incremental 3D reconstruction of the scene is conducted based on the robustly matched images. More than 99.8% of all the images are successfully oriented. The profiling analysis shows that the proposed methodology generates all the match pairs in 7.719 seconds. The precision, efficiency, and robustness of the proposed methodology are comprehensively analysed. The experimental and simulation results show that the proposed methodology is efficient and precise for large-scale UAV photogrammetry.

SEISMIC EVALUATION OF REINFORCED CONCRETE BUILDING USING NON-LINEAR TIME HISTORY ANALYSIS

Thestructure exposed to earthquake is required to show inelastic conduct that the misshaping in a part doesnt stay corresponding to the inside power. A non-direct investigation represents the inelastic reaction. Both material non-linearity and mathematical nonlinearity cases are considered. There is plastic distortion and energy assimilation in a part for more significant levels of interior power. This sort of nonlinear conduct is alluded to as material non-linearity. A few diverse hysteresis models are accessible to depict the conduct of various kinds of materials. Generally, these vary in the measure of energy they disperse in a given pattern of distortion, and how the energy dissemination conduct changes with an expanding measure of disfigurement. Turn hysteresis model is utilized. This study work utilizes fifteen-story and two cellars working of 40/60 undertaking of City Government of Addis Ababa Saving House Enterprise as a contextual investigation. A correlation is made between straight versatile examination and non-direct time history as far as story Displacement, Inter-story float, story Shear, Axial power, and Torsion. Along these lines, it ought not to be astonishing that structures endure harm during extraordinary ground shaking. The principal focal point of this work is to assess the seismic obstruction by utilizing non-direct time history investigation with the goal that the harm will be controlled satisfactorily. Seismic contribution to nonlinear unique examinations of constructions is normally characterized as far as speed increase time arrangement. Three references Earthquake Ankober 2016, EL-Centro 1940, and Sierra-Madre 1991 are utilized to create counterfeit time history utilizing time-space strategy. The time-space strategy is by and large viewed as a superior methodology for ghostly coordinating since this technique changes the speed increase time narratives in the time area by adding wavelets.

Pathogenesis and Treatment of Parkinson's Disease

Neurological disorders in humans can be modeled in animals using standardized procedures that recreate specific pathogenic events and their behavioral outcomes. The development of animal models of Parkinson’s disease (PD) is important to test new neuroprotective agents and strategies. Such animal models of PD have to mimic, at least partially, a Parkinson-like pathology and should reproduce specific features of the human disease. PD is characterized by massive degeneration of dopaminergic neurons in the substantia nigra, the loss of striatal dopaminergic fibers and a dramatic reduction of the striatal dopamine levels. The formation of cytoplasmic inclusion bodies (Lewy bodies) in surviving dopaminergic neurons represents the most important neuropathological feature of PD. Furthermore, the massive striatal dopamine deficiency causes easily detectable motor deficits in PD patients, including bradykinesia, rigidity, and resting tremor, which are the cardinal symptoms of PD. Over the years, a broad variety of experimental models of PD were developed and applied in diverse species. This review focuses on the two most common “classical” toxin-induced PD models, the 6-hydroxy-dopamine (6-OHDA model) and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model. Both neurotoxins selectively and rapidly destroy catecholaminergic neurons, whereas in humans the PD pathogenesis follows a progressive course over decades. This discrepancy reflects one important and principal point of weakness related to most animal models. This review discusses the most important properties of 6-OHDA and MPTP, their modes of administration, and critically examines advantages and limitations of selected animal models. The new genetic and environmental toxin models of PD (e.g. rotenone, paraquat, maneb) are discussed elsewhere in this “special issue.”

Changes in groundwater trace element concentrations before seismic and volcanic activities in Iceland during 2010–2018

We analysed temporal variations of trace element concentrations in groundwater from a 101 m-deep borehole (HA01) in northern Iceland during 2010–2018 and compared them with seismic and volcanic events that occurred in the same period to identify potential hydrogeochemical precursors. An increase of B, Al, V, Li and Mo concentrations started from eight months to one month before the 2014 Bárðarbunga eruption (~115 km from HA01), a major rifting event in central Iceland, while Ga and V concentrations began to increase one day and one month after the onset of the event, respectively. We also found that concentrations of some trace elements (Li, B, Ga, Mo, Sr, Rb and Fe) significantly increased before an Mw 5.0 earthquake that occurred ~80 km from the borehole in 2018. However, other notable hydrogeochemical changes were detected during the monitoring period without apparent correlation with the seismic and volcanic events in the region. This study shows that the systematic long-term hydrogeochemical monitoring in seismic and volcanic areas is critical to advance the science of seismic and eruptive precursors. Furthermore, the use of statistical tools, such as Principal Component Analysis (PCA) and Change Point (CP) detection can help identify the most useful chemical elements and validate the trend variability of those elements in the time series, reducing arbitrary choices of pre-seismic and pre-volcanic hydrogeochemical anomalies as potential precursors.

Opioid-free TIVA Improves Post- operative Quality of Recovery (QOR) in Patients Undergoing Oocyte Retrieval.

Oocyte retrieval is a part of in vitro fertilisation (IVF) procedures performed on an ambulatory basis. Total intravenous anaesthesia (TIVA) with opioid is shown to improve quality of recovery (QOR) after ambulatory surgery. Opioid-free anaesthesia (OF) is gaining popularity in recent times as it is associated with lesser post-operative side effects related to opioids. Quality of recovery is considered as one of the principal end points in ambulatory surgery. To compare quality of recovery using QOR-15 questionnaire between opioid-free TIVA and opioid-based TIVA at 24h after oocyte retrieval. A prospective randomised control study. Sixty six patients undergoing oocyte retrieval were prospectively selected. They were randomised into two equal group. OF TIVA group with dexmedetomidine (D) and propofol or opioid-based TIVA with fentanyl (F) and propofol. The primary outcome measured was quality of recovery using QOR-15 at 24h after oocyte retrieval. Secondary outcomes measured were incidence of bradycardia, post-operative nausea and vomiting, usage of rescue analgesia and total consumption of propofol. A statistically significant difference in total QOR-15 was observed between two groups (p value = 0.021) at 24h post-operatively. Usage of rescue analgesia and incidence of post-operative nausea and vomiting was less in opioid-free TIVA. Opioid-free TIVA improves post-operative QOR in patients undergoing oocyte retrieval.

An On-Orbit Calibration Method of Star Sensor Based on Angular Distance Subtraction

Star sensor needs real-time calibration to improve its navigation accuracy. Compared with other parameters, the position of the principal point is more easily affected by the measurement error, which leads to low calibration accuracy. Conventional star sensors on-orbit calibration methods mainly rely on the angular distance(AD) between stars. The observability of the principal point in this method and the calibration accuracy is not as well as that of other parameters. In this paper, an on-orbit calibration method of star sensor based on the angular distance subtraction(ADS) is proposed. The accuracy of the on-orbit calibration is improved by increasing the observability of the principal point in the calibration process, and the feasibility of this method is verified by the observability analysis. Finally, improved angular distance subtraction(IADS) models are proposed to solve the time-consuming problem of ADS method. In order to demonstrate the performance of the IADS models, simulation calibrations are conducted. The results show that the accuracy of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u₀</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v₀</i> of the IADS method is 62.7% and 15.9% higher than that of AD method when other parameters are set as nominal values. The calibration accuracy of the principal point is improved effectively.

ECPC-ICP: A 6D Vehicle Pose Estimation Method by Fusing the Roadside Lidar Point Cloud and Road Feature.

In the vehicle pose estimation task based on roadside Lidar in cooperative perception, the measurement distance, angle, and laser resolution directly affect the quality of the target point cloud. For incomplete and sparse point clouds, current methods are either less accurate in correspondences solved by local descriptors or not robust enough due to the reduction of effective boundary points. In response to the above weakness, this paper proposed a registration algorithm Environment Constraint Principal Component-Iterative Closest Point (ECPC-ICP), which integrated road information constraints. The road normal feature was extracted, and the principal component of the vehicle point cloud matrix under the road normal constraint was calculated as the initial pose result. Then, an accurate 6D pose was obtained through point-to-point ICP registration. According to the measurement characteristics of the roadside Lidars, this paper defined the point cloud sparseness description. The existing algorithms were tested on point cloud data with different sparseness. The simulated experimental results showed that the positioning MAE of ECPC-ICP was about 0.5% of the vehicle scale, the orientation MAE was about 0.26°, and the average registration success rate was 95.5%, which demonstrated an improvement in accuracy and robustness compared with current methods. In the real test environment, the positioning MAE was about 2.6% of the vehicle scale, and the average time cost was 53.19 ms, proving the accuracy and effectiveness of ECPC-ICP in practical applications.

An improved projector calibration method for structured-light 3D measurement systems

In a structured-light three-dimensional measurement system, understanding the optical configuration of the projector and suppressing the eccentricity error caused by the camera perspective projection are critical to realize high-precision measurement. In this paper, we analyze the special offset optical structure in commercial projectors, where a larger diameter lens is used to ensure the quality of the projected image, and the position of the principal point has been shifted. Meanwhile, a projector calibration strategy that makes the camera’s optical axis perpendicular to the target plane is proposed to avoid the pollution of perspective projection distortion. The sub-pixel correspondence based on homography transformation is performed by relying on the phase value of the fringe, and bundle adjustment optimization is used to further improve the accuracy and robustness of projector calibration. The experimental results demonstrate that the proposed calibration method can improve the calibration accuracy by 52.52%.

Mukalla, Hadramawt

Mukalla, Hadramawt, one of two principal points of departure for emigrants and today capital of the governorate in Yemen. Taken by Iain Walker in c.2006.

Ugni molinae Fruit as a Source of Bioactive Compounds with Good Quality Traits.

Since the intake of fruits and vegetables displays important effects on the incidence of several chronic diseases in humans, consumers' attention worldwide is focused on the identification of functional foods. In this sense, Ugni molinae (murtilla or murta fruit) is an important source of molecules with a strong antioxidant capacity that is widely used as a medicinal plant in Southern Argentina-Chile. Research on murtilla berries showed that this fruit and its leaves can be an excellent source of polyphenols and bioactive compounds with antibacterial and antioxidant capacity. This review is aimed at providing valuable information and discussing the available literature focused on four principal points: (i) fruit quality and plant physiology, (ii) compound content with bioactive properties, (iii) health properties for consumers of the fruit and leaves, and (iv) challenges for future research. Based on these four points, we propose that murtilla fruit can be a potential ingredient for new functional food products.

Dynamic reliability assessment of nonlinear structures using extreme value distribution based on L-moments

In this paper, an efficient method using the linear moments (L-moments) is proposed for dynamic reliability assessment of nonlinear structures subjected to non-stationary ground motions. The proposed method comprises three main steps. First, the extrema of structural responses are obtained from the random function-spectral representation model (RFSRM) and nonlinear time history analysis, in which the principal points are first combined with the RFSRM and a sampling strategy is suggested to determine the final samples of extrema by deleting close values. Second, after the samples of extrema are obtained, the first four L-moments can be estimated from their definitions. Finally, using the first four L-moments of extrema of structural responses, the probability distribution of extrema is approximated by a cubic normal distribution based on the L-moments and the corresponding failure probability of a nonlinear structure is calculated. Three numerical examples are presented to demonstrate the efficiency, accuracy, and usefulness of the proposed method for the dynamic reliability assessment of nonlinear structures, and the conventional spectrum representation method and subset simulation method are used for comparison.

Spatial Distribution and Morphological Identification of Regional Urban Settlements Based on Road Intersections

To measure and present urban size urban spatial forms, in solving problems in the rapid urbanization of China, urban territorial scope identification is essential. Although current commonly used methods can quantitatively identify urban territorial scopes to a certain extent, the results are displayed using a continuous and closed curve with medium- and low-resolution images. This makes the acquisition and interpretation of data challenging. In this paper, by extracting discretely distributed urban settlements, road intersections in OpenStreetMap (OSM), electronic maps, and urban expansion curve based on fractal thoughts have been used to present urban territorial scope and spatial form. Guangzhou, Chengdu, Nanjing, and Shijiazhuang cities were chosen as the identification targets. The results showed that the distance threshold corresponding to the principal curvature point of the urban expansion curve plays a vital role in the extraction of urban settlements. Moreover, from the analysis, the optimal distance thresholds of urban settlements in Guangzhou, Chengdu, Nanjing, and Shijiazhuang were 132 m, 204 m, 157 m, and 124 m, respectively, and the corresponding areas of urban territorial scopes were 1099.36 km2, 1076.78 km2, 803.07 km2, and 353.62 km2, respectively. These metrics are consistent with those for the built-up areas.

Error coupling analysis of the laboratory calibration method for a star tracker.

A star tracker should be well calibrated before it is equipped in order to achieve high accuracy. There exists, however, the coupling problem between the internal and external parameters for most commonly used laboratory calibration methods, which affect the star tracker's performance. We theoretically analyze the major aspects of the coupling mechanism based on the star tracker laboratory calibration model, which means the coupling between the principal point and the installation angle. The concept of equivalent principal point error, which illustrates the effectiveness of the calibration even with poor decoupling accuracy between the principal point and the installation angle, is introduced. Simulation and bench experiments are conducted to verify the laboratory calibration method and its coupling mechanism. The decoupling accuracy can be improved with more samples during calibration. In addition, the equivalent principal point error converges quickly and hardly affects the attitude of the star tracker, which is verified by both theory and experiment. The comprehensive calibration accuracy can still reach a high level even with poor decoupling accuracy.

Optical Coherence Tomography Assessment in Patients Treated With Rotational Atherectomy Versus Modified Balloons: PREPARE-CALC OCT.

[Figure: see text].

Experimental investigation on fatigue crack growth of directional solidified superalloy with single hole

In order to study the fatigue crack growth of directional solidified superalloy with single hole, the fatigue crack growth test of DZ125 was carried out under different stress levels. The fracture morphology of the specimens were analyzed by field emission scanning electron microscope, and the relationship between stress and life was fitted. It is found that the stress concentration around the hole and the defects lead to the crack initiation near the maximum principal stress point. The da/dN - Δ K satisfies Paris formula well.

Counterterrorism and the rule of law in an evolving European Union: plus ça change?

By taking the European Union (EU) as a principal focal point, this chapter will evaluate critically the rule of law challenges arising from the production and operation of counterterrorism norms. The article will focus on four case studies, two involving the rule of law ex ante (at the stage of adoption of EU law) and two involving the rule of law ex post (looking at its impact). In terms of ex ante rule of law challenges, the chapter will analyse the production of binding standards by the global executive and the trickle-down effect of these standards at the regional, EU and national level and the limits of scrutiny and justification of counterterrorism legislation on emergency grounds. In terms of rule of law ex post, the chapter will examine challenges of counterterrorism law to the principle of legality via over-criminalisation and the adoption of vague and broad definitions of terrorism, as well as challenges to the right to a fair trial and principle of effective judicial protection resulting from state arbitrariness in the mechanism of producing terrorist sanctions. The contribution will question whether the entry into force of the Lisbon Treaty, and the process of constitutionalisation of criminal law it entailed, has made a difference regarding the compliance of EU counterterrorism law with the rule of law.

Orthocorrection of KH-5 ARGON Satellite Imagery of Aral Sea

Declassified Intelligence Satellite Imagery is a unique source of historical environmental data. Three consecutive and overlapping images of the ARGON, the first dedicated mapping mission from 1962 depicting the surrounding of the Aral Sea were orthocorrected using Ground Control Points. As ARGON mission had a frame type camera, a least squares estimation of exterior orientation parameters were estimated using space resection. A modified space resection algorithm was used to estimate (beside the exterior orientation) the camera principal point coordinates and lens distortion correction coefficients. The overall accuracy of the orthocorrected images are in good accordance with the results of other authors.

Contextual Realism and the Real Meaning of Quantum Mechanics

I suggest a contextual realist interpretation of Carlo Rovelli’s relational quantum mechanics. The principal point is a correct understanding of the concept of reality and taking into account the categorical distinction between the ideal and the real. Within my interpretation, consciousness of the observer does not play any metaphysical role. The proposed approach can also be understood as a return to the Copenhagen interpretation of quantum mechanics, corrected within the framework of contextual realism. The contextual realism allows one to get rid of the metaphysical problems encountered by various interpretations of quantum mechanics, including the relational one. A wave function neither literally reflects an “exterior reality”, nor is it merely a predictive mathematical tool. In particular, an entangled wave function can be viewed as the formal cause of quantum correlations whose reality is contextual. The reduction of a wave function is not a real physical process. And there are no autonomous quantum events which would be different from the facts of their representation. The quantum measurement problem results from a confusion between the categories of the ideal and the real. It is dissolved logically. The quantum theory plays the role of a Wittgensteinian rule (norm), “measuring” physical reality within a language game of its application.

A detailed study on context-aware architectures in internet of things

Internet of things (IoT) is used to get the data around the world at your fingertip. As we move towards IoT the role of sensors has become vital. These sensors generate a vast amount of data. Sensors are used to sense and collects parallel information from the given set. We propose context-aware for IoT architectures which computerise the task. In this paper, we will discuss about the architecture of context-aware, IoT and context-aware reasoning. The principal objective of this paper is to audit existing architecture identified with context-aware and IoT and to make the comparative analysis table. The principal point is to enable the clients to present the issues and our proposed design enhances and delivers important information.