Curvilinear Approach Research Articles

“Version 1.3.0 pyfao56: FAO-56 evapotranspiration in Python”

The pyfao56 software package is a Python-based implementation of the standardized evapotranspiration (ET) methodologies described in Irrigation and Drainage paper No. 56 of the Food and Agriculture Organization of the United Nations, commonly known as FAO-56. This update improved pyfao56 by 1) adding an optional surface runoff methodology, 2) adding an extensive algorithm for automating the computation of irrigation schedules, 3) considering irrigation losses due to irrigation system inefficiencies, 4) adding an optional method to compute the transpiration reduction coefficient (Ks) based on the curvilinear approach from AquaCrop, 5) incorporating a module for computing 15 goodness-of-fit statistics between simulated and measured data, and 6) computing a cumulative seasonal water balance summary. Most of these updates arose from user requests to add new features or options, and the collaborations demonstrated the value of community-based development for rapid improvement and generalization of scientific software.

Unraveling the Dynamics of Intellectual Capital, Firm Performance, and the Influential Moderators—BIG4 Auditors and Group Affiliation

The importance of intellectual capital (IC) in past decades unfolds several dimensions of firm performance (FP). Still, the contradictory and inconclusive relationship between IC and FP in the literature motivates the researchers to explore further and understand the empirical connection using both linear and curvilinear approaches. Using the fixed-effect panel regression models on a sample of 795 non-financial firms of India from the financial years 2004–2005 to 2020–2021, this study reveals that, undoubtedly, the IC enhances the FP up to a certain threshold, and with any marginal investment, IC reduces the FP by forming the inverted U-shaped curve. Interestingly, the presence of BIG4 auditors in Indian firms helps to increase the FP with the help of IC, even for the group-affiliated firms. Thus, this study aligns with both value creation and cost concern perspectives and implies that management and regulatory bodies may adopt a balanced approach while enhancing the FP through IC, as the result suggests that investment in IC will not endlessly improve the FP in the Indian context.

Curvilinear Approach to Landing

ABSTRACT The article describes the problem of controlling an aircraft control when performing a landing on a curvilinear trajectory. The adoption of a curvilinear approach trajectory allows reducing the impact of air traffic on the areas adjacent to the airport. Performing the correct approach on the curvilinear path requires support. For the correct execution of the landing manoeuvre on the curvilinear track, it is necessary to establish reference points so that the repeatability of the manoeuvre is ensured, especially in the case of landing more than one aircraft at the same time. In the following parts, the landing control system is presented. Particularly carefully presented is the issue of performing tests of the designed control system, which in the case of the aircraft control system during the approach to landing must be extremely thoroughly verified. The test plan included both verification the correctness of the adopted control laws and their robustness to interference occurring as a result of atmospheric air streams.

Design of Turbo-Roundabouts Based on the Rules of Vehicle Movement Geometry on Curvilinear Approaches

The construction of turbo-roundabouts is an increasingly frequent choice when it comes to improving flow capacity and traffic safety at road intersections. The existing design guidelines, as a rule, give parameters for turbo-roundabouts with approaches set at right angles to each other. The article presents turbo-roundabout design methods, taking into account swept path analyses of the chosen design vehicles when the approach legs are curvilinear and oriented to each other at a non-right angle. Based on the analysis of three different design vehicles, it was proven that their swept paths have a major influence on the geometrical parameters of the roundabout and, consequently, on the land take area, i.e., they can significantly impact the project’s construction costs. In the case of curvilinear approaches, which are oriented to each other at a non-right angle, it is impossible to impose on the designer specific values of the circulatory lane widths and the entry and exit curve radii as they depend primarily on the chosen design vehicle. The aim of the article was to demonstrate that in the case of the curvilinear approach on the Basic type turbo-roundabout, the design process should include the swept path analysis for the chosen design vehicle for each of the approaches. This should lead to the design of wider swept paths and higher curve lane divider entry and exit radii.

A curvilinear approach for solving the hybrid nanofluid model

When an object moves alongside a curved surface, it shows a curvilinear motion. The perception of curvilinear motion is majorly used in applications which are associated with centripetal and centrifugal forces. In this analysis, we studied the behaviour of nano-fluid and hybrid nano-fluid via curved surface with combined effects of heat generation and porous medium. For nano-fluid the combination of base fluid methanol and nano-particles AA7075 are assumed, while for hybrid nano-fluid base fluid methanol and nano-particles AA7075+AA7072 are used. AA7072 is mixture of zinc and alumina with some metals like copper, silicon and ferrous. Similarly AA7075 is mixture of magnesium, alumina and zinc with metals copper, silicon and ferrous. The partial differential equations are converted into ordinary differential equations by using similarity transformation. With the help of MATLAB software we used Bvp4c method to draw the graphs of the resulting equations and also we discuss the effect of solid volume fraction φ1, φ2, curvature parameter λ, Heat generation ω and porous medium ε for nano-fluid and hybrid nano-fluid. By enhancing the curvature parameter and volume fraction the temperature and velocity profile also enhances while the velocity profile reduces for porous medium and temperature profile increases for heat generation parameter. Nusselt number and skin friction effects are studied in the form of tables. An entropy generation analysis is also conducted.

Oriented manifold-based error tracking control for nonholonomic wheeled autonomous vehicles on Lie group for curvilinear approach

This paper considers the trajectory tracking control of wheeled autonomous vehicles (WAV) with slipping in the wheels, i.e., when the kinematic constraints are not satisfied. Usually, the coordinates system used to represent all control problems suggest invariant subspaces mutually orthogonal, but this approach can not be enough to treat curvatures significative large at different navigation speed. In order to get a slight im- provement on this topic, there are previous works showing that the kinematic problem (commonly associated with an outer loop) can be resynthesized by using other invariant subspaces, i.e., another representation of the configuration space. For this reason, the proposal reported here uses an oriented-manifold parametrized by a coordinate system on a curve viewpoint of the trajectory to describe the kinematic problem, however, the dynamic control law remains faithful to the singular perturbation approach with invariant subspaces mutually orthogonal, thus, it is possible to include the flexibility through a small factor in the dynamic model (well-known as ε), responsible to avoid the good-performance of the kinematic constraints. Only a common curvature-transformation between orthogonal and curve coordinates will be used to couple both approaches. Finally, it will be observed that when the controller is applied to the control scheme the behavior of the tracking is meaningfully improved.

Design, Fabrication, and Testing of a Flexible Three-Dimensional Printed Percutaneous Needle With Embedded Actuators

Abstract Percutaneous needle-based procedures have replaced open surgeries in cancer treatments to perform the tasks with minimal invasiveness to the tissue. Precise placement of the needle at target positions in cancer diagnostic (e.g., breast biopsy) or therapeutic (e.g., prostate brachytherapy) procedures governs the success of such procedures. Also, in many needle insertion applications, it is desired to steer away from critical organs or to maneuver around anatomical obstacles in tissue. This work introduces a flexible three-dimensional (3D) printed percutaneous needle with embedded actuators for improved navigation inside the tissue toward the target. The needle is manipulated via a programmed portable motorized control unit to realize an average angular deflection of about 15 and 14 deg in air and a tissue-mimicking phantom, respectively. We demonstrated the needle's capability to reach the target, while avoiding obstacles. We also demonstrated that the flexible needle can be guided through a desired trajectory by controlling its angular deflection and axial movement. The 3D deflection of the needle is expected to assist in breast cancer lumpectomy for multiple extractions of tissue samples or in prostate brachytherapy via a curvilinear approach. The flexible needle may help reducing the complexity of current path planning algorithms, and thereby improve efficiency of closed-loop control systems in needle steering.

Introducing differential calculus in Spain: The fluxion of the product and the quadrature of curves by Tomàs Cerdà

Differential calculus was introduced into eighteenth-century Spain through the teaching of several authors in different scientific institutions. One of the more noteworthy of these Spanish authors was the Jesuit Tomàs Cerdà (1715–1791), who taught mathematics at the College of Cordelles in Barcelona and at the Imperial College in Madrid. This mathematician introduced differential calculus through the manuscript entitled ‘Tratado de Fluxiones’ (1757–1759), which had as a main source The Doctrine and Application of Fluxions (1750) by Thomas Simpson (1710–1761). Our aim in this paper is to analyse Cerdà’s special contribution to the introduction into Spain of the Newtonian theory of fluxions based on Simpson’s definition of a fluxion. Specifically, the paper shows that Cerdà deduced the fluxion of the product of two variables and the area under a curve by previously establishing the fluxion of a curvilinear surface, a particular and different approach to that employed by other contemporaneous mathematicians in Spain.

Compact 3D-Printed Active Flexible Needle for Percutaneous Procedures.

Needle-based intervention has been a popular procedure for diagnosis and treatment of many types of cancer. However, poor needle placement and tumor visualization have been among the challenges resulting in poor clinical outcomes. There has been a lot of progress in medical imaging technology, but the structure of surgical needles has remained unchanged. This work presents a wire-driven 3D steerable, 3D-printed active needle for improved guidance inside the tissue toward the target. The needle is manipulated by 3 embedded tendons via a programmed motorized control unit. Feasibility tests in a tissue phantom showed an average 3D needle angular deflection of about 11°. This amount of angular deflection is expected to assist prostate brachytherapy via a curvilinear approach.

CRB modification to retromandibular approach for management of subcondylar fractures.

The aim of this study was to evaluate the efficacy of CRB modification of retromandibular approach to gain surgical access for open reduction and internal fixation of mandibular subcondylar fractures. A total number of 264 sustained extra-capsular subcondylar fractures from 230 patients were selected for the study over the period of 5 years. Evaluation of intraoperative accessibility, postoperative facial nerve function, postoperative complications and scar was carried out. All the patients were treated using CRB Curvilinear approach. Patient follow up was recorded for 1 year on a regular interval basis. Symptoms of postoperative facial nerve injury were seen in 2 patients which recovered with time, postoperative complications were not encountered in any case and minimum scar mark hidden in the cervical skin crease. Hence open reduction and internal fixation for Subcondylar fracture of mandible by using the CRB modification of retromandibular approach is a good alternative for other conventional approaches in having ease of access, ease of fixation, reduced incidences of injury to facial nerve and its branches with good aesthetic outcome.

Unsteady flow simulation using the curvilinear multiple-relaxation-time lattice Boltzmann method: Danube River case study

In order to introduce the lattice Boltzmann method as a competitive approach compared to traditionally based mathematical models when river and coastal hydraulics are considered, the innovative curvilinear multi-relaxation-time lattice Boltzmann method for solving 2D flow equations transformed in curvilinear coordinate system is utilized. The curvilinear approach implemented in the multi-relaxation-time lattice Boltzmann method is tested on a geometrically simple non-prismatic channel and on a section of the Danube River. Steady flow tangential velocity measurements are used in case of the channel model verification, while in case of the Danube unsteady flow is examined. Corresponding velocity and water level measurements acquired during a period of five days are used for calibration and verification of the Danube model, while an alternative mathematical model based on the traditional fractional-step approach has been exploited for comparison. The presented results confirm the aptness of the proposed model to simulate flow in natural water bodies effectively and accurately, therefore it is fully competitive with the classic computational fluid dynamics models.

Curvilinear tracing approach for recognition of Kannada sign language

Sign languages are used as the main mode of communication for vocally disabled people; however, the diversity in sign symbol representation limits its usage to a particular region. There is a huge diversity in sign symbol representation from one country to another, one state to another. In India there are different sign languages observed for each state region. It is hence very difficult for one region individual to communicate to another using a significant symbol. This paper proposes a curvilinear tracing approach for shape representation and recognition of Kannada sign language to generate corresponding characters in Kannada language. To develop this approach, a dataset is created with all Swaragalu, Vyanjanagalu, and numbers in Kannada language. The dataset is formed by defining a vocabulary for different sign symbols used in common interfacing. In the representation of sign language for recognition, edge features of hand regions are considered to be an optimal feature representation of sign language.

Curvilinear tracing approach for recognition of Kannada sign language

Curvilinear tracing approach for recognition of Kannada sign language

Effectiveness of curvilinear approach in dissection of Descemet's membrane: first 500 cases - factors influencing graft preparation.

To confirm the reproducibility of manual graft preparation using curvilinear forceps and evaluate the incidence and type of structural abnormalities of Descemet's membrane (DM) preventing successful grafts preparation. Five hundred corneo-scleral buttons were prepared. Factors such as endothelial cell number before preparation, donor age, post-mortem time, time in culture, pigmentation of the trabecular meshwork and preparation characteristics of the fellow eye were analysed. According to the preparation characteristics, three groups were formed: A, uncomplicated; B, complicated preparation with stripping from the contralateral side; and C, failure of preparation. Three failed grafts were examined by transmission electron microscopy (TEM). Using curvilinear forceps, manual separation of DM was achieved without any adverse effects in 457 of 500 corneas (91.4%). In 32 corneas (6.4%) with micro-tears during preparation, stripping from the opposite side was possible. However, 11 of the 500 corneas (2.2%) showed extremely strong adhesion leading to multiple tears of DM and preventing successful preparation of the graft. Endothelial cell number, donor age, post-mortem time, time in culture and pigmentation of the trabecular meshwork showed no significant correlation with failure to successfully obtain a DM graft. Complicated graft preparations of one eye showed a highly significant correlation with complicated graft preparations in the fellow eye. TEM analysis of failed grafts showed abnormal invasion of stromal parts into the DM, cell accumulation and pigmentation in the DM plane. Using curvilinear forceps for dissecting of the graft shows valid and reproducible results in the vast majority (97.8%) of donor corneas.

Gas-phase structure of 1,8-bis[(trimethylsilyl)ethynyl]anthracene: cog-wheel-type vs. independent internal rotation and influence of dispersion interactions.

The gas-phase structure of 1,8-bis[(trimethylsilyl)ethynyl]anthracene (1,8-BTMSA) was determined by a combined gas electron diffraction (GED)/mass spectrometry (MS) experiment as well as by quantum-chemical calculations (QC). DFT and dispersion corrected DFT calculations (DFT-D3) predicted two slightly different structures for 1,8-BTMSA concerning the mutual orientation of the two -C-C[triple bond, length as m-dash]C-SiMe3 units: away from one another or both bent to the same side. An attempt was made to distinguish these structures by GED structural analysis. To probe the structural rigidity, a set of Born-Oppenheimer molecular dynamics (BOMD) calculations has been performed at the DFT-D level. Vibrational corrections Δr = ra - re were calculated by two BOMD approaches: a microcanonically (NVE) sampled ensemble of 20 trajectories (BOMD(NVE)) and a canonical (NVT) trajectory thermostated by the Noose-Hoover algorithm (BOMD(NVT)). In addition, the conventional approach with both, rectilinear and curvilinear approximations (SHRINK program), was also applied. Radial distribution curves obtained with models using both MD approaches provide a better description of the experimental data than those obtained using the rectilinear (SHRINK) approximation, while the curvilinear approach turned out to lead to physically inacceptable results. The electronic structure of 1,8-BTMSA was investigated in terms of an NBO analysis and was compared with that of the earlier studied 1,8-bis(phenylethynyl)anthracene. Theoretical and experimental results lead to the conclusion that the (trimethylsilyl)ethynyl (TMSE) groups in 1,8-BTMSA are neither restricted in rotation nor in bending at the temperature of the GED experiment.

비윤리적 친조직 행동에 대한 지각된 윤리적 조직 문화의 비선형적 관계 및 조직 동일시의 조절 효과

비윤리적 친조직 행동에 대한 지각된 윤리적 조직 문화의 비선형적 관계 및 조직 동일시의 조절 효과

WE‐A‐108‐08: Development of Shape Memory Alloy Actuated Flexible Needle Control System for Prostate Brachytherapy

Purpose: To develop and evaluate a controller system capable of accurately guiding a shape memory alloy (SMA) actuated flexible needle to deliver therapeutic agents using a curvilinear approach for prostate brachytherapy for improved geometrical and dosimetric conformity. Methods: An experimental needling system was developed using flexible cannula of a 17‐gauge HDR needle actuated by Nitinol SMA. Experiments were performed in air at room temperature (22‐degC) and in controlled warm water‐bath (38‐degC, which is close to human body temperature). A silicone‐based coating was applied to the SMA wire‐actuator for electrical insulation in water. Two closed‐loop control algorithms, proportional‐derivative‐integral (PID) and PID‐P3 (with cubic term of positional errors), were implemented and tested using LabVIEW (National Instruments, version‐4.3.3). The needle and SMA actuator were integrated with a 5‐DOF Aurora (NDI, Ontario, Canada) electromagnetic (EM) sensor embedded at the tip of the needle for trajectory tracking. Performance was evaluated in terms of EM‐sensor feedback sampling intervals of 100ms, 500ms, and 1000ms, and needle‐tip displacements of 0.5mm, 2mm, and 2.5mm. Controller gains were experimentally determined. Results: PID‐P3 controller outperformed PID controller in all measured domains. Sampling time of 100ms yielded unstable performance for all displacements in water. Sampling time of 500ms with needle‐tip displacement of 2mm yielded the optimal performance with smaller overshoot and higher stability. In‐water results were comparable to in‐air measurements for the optimum performance at 500ms sampling time and 2mm displacement. Conclusions: PID‐P3 based SMA‐actuated needle appears to be adequate for conforming to the radius of curvature of a prostate gland, as well as operating effectively in human body. For small displacements (<0.5mm), fast rise‐time was observed, however, stability suffered. For larger displacements (>=2mm), stability increased but was hampered by slower rise‐time. Further investigation of PID‐P3 and other control algorithms (neuro‐fuzzy and adaptive) may offset slow rise‐time and increase stability. This study was funded by the U.S. Army Medical Research and Materiel Command(Garnt #W81XWH‐11‐1‐0399).

All-Source Basal Vitamin D Inputs Are Greater Than Previously Thought and Cutaneous Inputs Are Smaller

AbstractThe magnitude of vitamin D inputs in individuals not taking supplements is unknown; however, there is a great deal of information on quantitative response to varying supplement doses. We reanalyzed individual 25-hydroxyvitamin D [25(OH)D] concentration data from 8 studies involving cholecalciferol supplementation (total sample size = 3000). We extrapolated individual study dose-response curves to zero concentration values for serum 25(OH)D by using both linear and curvilinear approaches and measured seasonal oscillation in the serum 25(OH)D concentration. The total basal input (food plus solar) was calculated to range from a low of 778 IU/d in patients with end-stage renal disease to a high of 2667 IU/d in healthy Caucasian adults. Consistent with expectations, obese individuals had lower baseline, unsupplemented 25(OH)D concentrations and a smaller response to supplements. Similarly, African Americans had both lower baseline concentrations and lower calculated basal, all-source inputs. Seasonal oscillation in 4 studies ranged from 5.20 to 11.4 nmol/L, reflecting a mean cutaneous synthesis of cholecalciferol ranging from 209 to 651 IU/d at the summer peak. We conclude that: 1) all-source, basal vitamin D inputs are approximately an order of magnitude higher than can be explained by traditional food sources; 2) cutaneous, solar input in these cohorts accounts for only 10–25% of unsupplemented input at the summer peak; and 3) the remainder must come from undocumented food sources, possibly in part as preformed 25(OH)D.

A curvilinear approach to the kinetic analysis of linoleate peroxidation in aqueous liposomes by 2,2′azobis(2-amidoinopropane) dihydrochloride

Lipid peroxidation is a common feature of many chemical and biological processes, and is governed by a complex kinetic scheme. A fundamental stage in kinetic investigations of lipid peroxidation is the accurate determination of the rate of peroxidation, which in many instances is heavily reliant on the method of finite differences. Such numerical approximations of the first derivative are commonly employed in commercially available software, despite suffering from considerable inaccuracy due to rounding and truncation errors. As a simple solution to this, we applied three empirical sigmoid functions (viz. the Prout–Tompkins, Richards & Gompertz functions) to data obtained from the AAPH-mediated peroxidation of aqueous linoleate liposomes in the presence of increasing concentrations of Trolox, evaluating the curve fitting parameters using the widely available Microsoft Excel Solver add-in. We have demonstrated that the five-parameter Richards’ function provides an excellent model for this peroxidation, and when applied to the determination of fundamental rate constants, produces results in keeping with those available in the literature. Overall, we present a series of equations, derived from the Richards’ function, which enables direct evaluation of the kinetic measures of peroxidation. This procedure has applicability not only to investigations of lipid peroxidation, but to any system exhibiting sigmoid kinetics.

A novel curvilinear approach for prostate seed implantation

A new technique called "curvilinear approach" for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V(100)). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D(90), V(150), V(200)), urethra (D(30), D(10)) and rectum (D(5), V(100)) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D(30) reduced by 10.1% (p < 0.01) and D(10) reduced by 9.9% (p < 0.02). Reduction in rectum dose D(5) was 18.5% (p < 0.03) and V(100) was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V(150) and V(200) coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V(150), V(200)) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the curvilinear implantation approach is dosimetrically superior to conventional rectilinear implantation technique.