Cubic Model Research Articles

Shape Optimization of a Rotating Cantilever Beam Considering Its Modal and Stress Characteristics

It is well known that natural frequencies increase when a cantilever beam rotates about the axis perpendicular to its longitudinal axis. Such phenomena that are caused by centrifugal inertia forces are often referred to as the stiffening effects. Occasionally it is necessary to control the variation of a natural frequency or the maximum stress of a rotating beam. By changing the thickness of the rotating beam, the modal or the stress characteristics can be changed. The thickness of the rotating beam is assumed to be a cubic spline function in the present work. An optimization method is employed to find the optimal thickness shape of the rotating beam. This method can be utilized for the design of rotating structures such as turbine blades and aircraft rotary wings.

356 Composition of Leafy Greens as Affected by Season and Conventional or Organic Fertilization

Leaf tissue composition may depend on season and method of fertilization. Lettuce and spinach were grown in spring, fall, and winter in unheated high tunnels using organic or conventional fertilization. The root medium was either perlite fertilized with a nitrate-based complete soluble fertilizer, or leaf compost/perlite 1:1 v/v fertilized with cottonseed meal. Growth rate did not differ due to the method of fertilization, but specific leaf area was 10% greater with compost. Growth in compost raised the concentrations of total reduced nitrogen, phosphate, and potassium in both species. Effects of season were factored with a 3rd-order polynomial in Julian day. Nitrate, total phosphorus and potassium varied with season. Interaction of effects of season and fertilization were only significant for total reduced nitrogen and phosphate in leaves of lettuce. The difference in nitrogen due to fertilization was larger in fall harvests than at other times of year. There was a similar, but nonsignificant, trend with time for total reduced nitrogen in spinach. Differences in nitrate due to fertilization were small, compared to those of reduced nitrogen. The same seasonal trend in potassium was seen in both species, and for both methods of fertilization. Concentrations were highest in spring and lowest in fall.

Beak length analysis of the Southern Ocean squid Psychroteuthis glacialis (Cephalopoda: Psychroteuthidae) and its use for size and biomass estimation

A detailed analysis of beak length to body size and mass measurements was carried out for the glacial squid Psychroteuthis glacialis, which is an endemic cephalopod species in the Southern Ocean. Beak lengths (lower rostral length) were measured from 211 specimens which had been sampled in the Atlantic sector of the Southern Ocean. The basic idea was to find some calibration model in order to inter- or extrapolate missing mantle length and/or wet body mass data by means of beak lengths. The relationships between beak length and mantle length/wet body mass bear essential information for future use in biomass estimates in Southern Ocean top predators, since beaks of P. glacialis occur frequently in the stomach contents of Antarctic seabirds, seals and toothed whales. Therefore, lower rostral lengths were plotted against both mantle length and wet body mass to determine the relationship between these variables. The relationships had limited scatter and very high coefficients of determination, showing that lower rostral length is a good predictor of the squid's mantle length and wet mass. A non-linear 3rd order polynomial regression of lower rostral length against mantle length was identified as the best fitted calibration model, explaining 93% (R 2) of the associated variance. The relationship between lower rostral length and wet body mass was empirically well fitted through regressing ln-transformed values of lower rostral length against wet body mass, explaining 95% (R 2) of the associated variance. The present investigation provides measurements for a wide size range of P. glacialis individuals compared to earlier studies, which were limited on very small data sets.

Frontal surface area measurements in national calibre swimmers

The purpose of this study was to measure frontal surface area of swimmers during the freestyle and to compare measured values to values obtained using different computational methods. Twenty-six National elite freestyle swimmers were the subjects of this study (15 men, 11 women). Subjects were video taped from the front in a 50 m pool as they swam a maximum 50 m freestyle sprint. A 5-m area was calibrated every metre, and a 3rd order polynomial was fitted to the data to enable calibration at any distance within that area. Frontal surface area during one complete stroke cycle was measured by digitizing the outline of the swimmer's trunk only (TRUNK) and secondly by digitizing the outline of the trunk, arms and legs (BODY). Frontal surface area was also calculated using the methods of previous workers (CLARYS, VOLUME2/3). For the women, all methods correlated well with each other except TRUNK, which did not correlate with any of the other methods. All methods correlated well with each other for the men (P < 0.05). A one-way ANOVA with a post-hoc Scheffe revealed that, for the women, all methods were significantly different from each other except for TRUNK and CLARYS. For the men, all methods were significantly different from each other. These differences in frontal surface area could significantly alter calculations involving the active or passive drag force in swimming.

Estimating inspection time: response probabilities, the BRAT IT algorithm, and IQ correlations

Bates and Eysenck (1993), used a 3rd-order cubic polynomial curve fitting procedure on correct-response probabilities computed from the trial record of individual research participants ( N = 70) in an inspection time (IT) task. They demonstrated that this methodology produced estimates of IT that, when correlated with full-scale IQ scores (assessed by Jackson's Multidimensional Aptitude Battery), provided a measure of agreement that exceeded that given by the Barrett BRAT IT algorithm. The correlation between IT computed via the BRAT algorithm and full-scale IQ in this sample was −0.35, that between IQ and the cubic polynomial estimate was −0.35. When removing one outlier observation from the polynomial estimate data, this correlation increased to −0.47. Further, Bates and Eysenck also removed a further 5 cases from the dataset on the basis of “bad fit” of the data by the polynomial function, this had the effect of increasing the correlation to −0.62. However, it is demonstrated in this paper that when systematic, explicit, and quantified, criteria are applied to the outlier analysis, and replication of the results is sought across a further four IT datasets, the correlations between the BRAT algorithm parameters and those produced from 3 curve equation functions are actually equivalent. The average systematic outlier-corrected correlation between IT and IQ for both the BRAT and cubic polynomial estimates is −0.34. Further, the unadjusted correlations between BRAT IT estimates and cubic polynomial estimates all exceed 0.95, across all 5 datasets. It is concluded that given the relative difficulty of producing exact polynomial estimates at 0.76 response probability, the inappropriate use of a cubic polynomial for a function bounded by (0,1), and the perhaps inappropriate data produced by the BRAT algorithm for this type of approach to IT estimation, the use of the curve-fit procedure is sub-optimal with regard to this particular form of IT estimation algorithm.

Nonlinear behavior of magnetoresistive heads

Anisotropic magnetoresistive heads for magnetic recording are nonlinear transducers, unlike inductive read heads. The associated transfer characteristics are often represented by a 3rd order polynomial. Any nonlinearity in either the recording process or the read process can compromise detection schemes that rely on linear superposition for proper signal equalization. In this paper, the effects of nonlinear MR head transfer characteristics are studied in isolation from other effects by employing micromagnetic modeling of the head and read process. Effects of head saturation on equalization are illustrated.

The Thermodynamic Analysis of Optimum Ignition Timing. 4th Report. Relationship between Ignition Timing and Rejected Heat from Power Stroke to Cylinder Wall and Exhaust Gas.

The author has previously reported that a work done by a power stroke of Gasoline Engine is written as a function of some factors (ignition timing, combustion duration, engine speed etc.) using a pressure diagram in cylinder which is an approximate solution of energy conservation equation. In this report, the author is going to express an rejected heat to cylinder wall and exhaust gas as a similar function of factors mentioned above as the work done by cycle. The analysis shows that ; (1) a rejected heat to cylinder wall is written as a 3rd order polynomial of ignition timing, and increases with advance of ignition timing. (2) a rejected heat to exhaust gas is also written as a 3rd order polynomial of ignition timing, and increases with retard of ignition-timing. (3) total rejected heat is approximatly expressed as 2nd order polynomial of ignition timing, and has a minimum value at MBT.

The quasiconvexification of a cubic polynomial at the origin

The quasiconvexification of a cubic polynomial at the origin

Research on the Image Structure of a Town in the Hilled Rural Area of Iwate Prefecture, from the Inhabitants, Movers and Visitors

This research is to take to clarify of the image structure of hilled rural area of Iwate prefecture, as the inhabitants, movers and visitors of Karumai-Town in Iwate prefecture. We did the comparing analysis of the image structure of Karumai-Town according to the 'CUBIC MODEL OF LOCAL IMAGE' which is the model of image structure of inhabitants, movers and visitors. The image structures were not only from inhabitants's but also from visitors's and movers's of Karumai-Town. As a result, we found the image structures of Karumai-Town more open and unique than ever that come from the inhabitants, visitors and movers to be difference.

The effect of MR head nonlinearity on MDFE and PRML performance

The detection performance of multi-level decision feedback equalization (MDFE) and partial response with maximum likelihood detection (PRML) in the presence of magnetoresistive (MR) head nonlinearity is investigated through simulation. Two models are used to characterize the MR head nonlinearity: (1) a transfer function curve based on measurement and (2) a 3rd-order polynomial model. The results indicate that MDFE is more robust to MR head nonlinearity than PRML, especially to head saturation.

Reproducibility of kinetics of electromyogram spectrum parameters during dynamic exercise.

During incremental exercise on a cycle ergometer a study was made of the reproducibility of changes in electromyographic activity (EMG) of human quadriceps muscles. Seven subjects performed three periods of incremental exercise either every 2 weeks (G1: four subjects) or 6 weeks (G2: three subjects). Each test was normalized with respect to the maximal aerobic power (MAP) of the subject. It consisted of a quasilinear increase in mechanical power (from 20% to 100% MAP) during 8 min. For rectus femoris muscle activity, changes in total power spectrum (PEMG) and in mean power frequency (MPF) were fitted by a 3rd order polynomial function (named profile) and normalized with respect to the maximal value for PEMG and to the mean value for MPF. A curvilinear increase was found for PEMG. The MPF kinetics varied from one subject to another. These changes were either a continuous increase, or a continuous decrease, or an increase followed by a decrease. Only for G2, was MAP determined before each test in order to update the limits of the test. A good reproducibility of PEMG was shown by its mean magnitude [95.88%, (SD 3.92)] and by computing a mean correlation coefficient between profiles two by two [r2 = 0.948 (SD 0.028) n = 21]. Intraclass coefficient correlation (ICC) calculated for each subject indicated a high level of reproducibility for five of the seven subjects (ICC > 0.80). No clear effect of MAP updating on PEMG and MPF profile reproducibility was observed. Thus it is suggested that MPF kinetics may characterize a subject at a given moment while PEMG kinetics may illustrate a normal profile, and they may both characterize EMG changes for a population during incremental exercise.

Relationships between grain-filling parameters, fertility, earliness and grain protein of durum wheat in a Mediterranean environment

Seven Italian durum wheat ( Triticum turgidum L. var. durum) cultivars characterized by different height, time to anthesis, fertility and kernel weight were compared under different moisture levels and soil types in two experiments. Duration, and maximum and average rate of grain-filling (GF) were estimated from 2nd and 3rd order polynomials, regressing kernel weight on growing degree days (GDD, base temperature 9°C). In both experiments Messapia was the earliest cv, flowering between 132 and 139 days after sowing (das), and Vespro and Creso the latest, flowering between 141 and 148 das. The largest kernels, ranging between 51.8 and 59.5 mg, were always realized by these three cultivars and were always associated with the highest rates of GF. Average rates ranged from 105 to 152 μg °C day −1 and were significantly correlated, both environmentally and phenotypically, with maximum kernel weight. Maximum rates of GF, ranging from 172 μg °C day −1 in the genotype D3415 to 282 μg °C day −1 in cv Creso, were only phenotypically correlated with maximum kernel weight. GF duration was related to earliness as it ranged from a minimum of 380 GDD in the late cv Vespro, to a maximum of 481 GDD in the earliest cv Messapia. Fertility varied greatly, from 37 kernels per spike in Creso and Vespro, to 61 kernels per spike in Vespro. Significant differences in grain protein were recorded between cultivars (8.9% in Karel to 15.8% in D3415) and soils (10.8% and 14.1%). In this environment, large kernels can be achieved with genotypes characterized by high rates of GF, irrespective of earliness, and without negative effects on spike fertility and on grain protein content.

IMPAIRED NEONATAL CEREBRAL BLOOD FLOW AUTOREGULATION IN GROUP B STREPTOCOCCAL MENINGITIS IS NOT MEDIATED BY TUMOR NECROSIS FACTOR (TNFα).• 977

Group B streptococcal (GBS) meningitis impairs cerebral blood flow (CBF) autoregulation in newborn piglets probably via inflammatory mediators in response to GBS. We tested whether TNFα mediates early CBF impairment by GBS in 3 grps of awake sedated newborn piglets (0-5 days). Grp 1 (CTRL), n=8 had normal saline (0.5ml) via the lateral cerebral ventricle (icv), Grp 2(n=7) had heat killed unencapsulated GBS (109 cfu, 0.5ml icv) and Grp 3 had TNFα, 1,000 units icv, 0.5ml). CBF was measured over a range of mean arterial blood pressure (35-125 mmHg) induced by inflating balloon tipped catheters at the aortic root to produce cerebral hypotension or descending aorta for hypertension at 5 time points: 15 min pre (baseline) and post injection of either saline, GBS or TNFα), and during randome hypo-, normo-, and hypertension. RESULTS: 1) Grp 1, CBF and CPP (cerebral perfusion pressure) best fitted a 3rd order polynomial regression (R2=0.57,p=0.008) with constant CBF at 50-90 mmHg CPP. 2) Grp 2, GBS caused direct correlation in CBF and CPP (50-110 mmHg), r=0.52, p <0.05. Grp 3 (TNFα) had CBF constant at 50-110 mmHg, r=0.12, p=NS. Cerebrovascular resistance correlated with CPP(50-125 mmHg) in CTRL (r=0.458,p=0.009)and TNFα grps (r=0.60, p=0.002) but not in GBS grp (r=0.06, p=.8). Thus, TNFα did not mediate early impairment in neonatal CBF autoregulation in GBS meningitis and therapies directed to TNFα may not correct CBF changes.Figure

Development of a Motion Control Algorithm for the Automatic Operation System of Overhead Cranes

A search algorithm for the collision free, time optimal transport path of overhead cranes has been proposed in this paper. The map for the working environment of overhead cranes was constructed in the form of three dimensional grid. The obstacle occupied region and unoccupied region of the map has been represented using the octree model. The best-first search method with a suitable estimation function was applied to select the knot points on the collision free transport path to the octree model. The optimization technique, minimizing the travel time required for transporting objects to the goal while subjected to the dynamic constraints of the crane system, was developed to find the smooth time optimal path in the form of cubic spline functions which interpolate the selected knot points. Several simulation results showed that the selected estimation function worked effectively insearching the knot points on the collision free transport path and that the resulting transport path was time optimal path while satisfying the dynamic constraints of the crane system.

Numerical computation of turbulent flow in a square sectioned $180^{\circ}$ bend by low-Reynolds-number second moment turbulence closure

A new low Reynolds number nonlinear second moment turbulence closure was introduced to analyze a square sectioned 180.deg. bend flow. Inclusion of nonlinear return to isotropy term and cubic mean pressure strain term has brought out a marked improvement in the level of agreement with measured velocity profiles. Optimization of present closure was performed by comparison of computed velocity profiles with the experimental ones with variation of nonlinear return to isotropy term and quadratic and cubic pressure-strain model. Progressive vortex breakdown due to the interaction of primary and secondary flows was well captured by using the optimized second moment turbulence closure.

Exact Solutions for Free Vibration in a Single-Degree-of-Freedom System Having a Spring with an Arbitrary Cubic Function. Introductory Remarks.

For a single-degree-of-freedom system having a spring function (in addition to a linear term) with a cubic term (Duffing oscillator) or a quadratic term (Helmholtz oscillator), the exact solutions of the free vibration are expressed in terms of Jacobian elliptic functions. However, for a system having a spring function with all terms from a constant (0th order) up to a cubic (3rd order), the most generalized 3rd-order polynomial including an asymmetrical spring, the situation has not always been clear since Duffing's early days. A certain transform was proposed to convert the relevant system into a standard (symmetrical) Duffing system previously, but the algorithms were poor and some difficulties were found in the computation In this paper, revised algorithms are discussed to realize accurate numeration. It also becomes possible to obtain the solution for a given natural frequency as well as for a given initial rest amplitude. As an example the result for an asymmetrical soft spring system is demonstrated.

Exercise intensity and renal hemodynamics

This study investigated the effects of exercise intensity on renal hemodynamics. Three healthy male subjects underwent exercise tests on a bicycle ergometer at 7 different work loads for 15 min. The indicators of exercise intensity employed in this study were the percentage of maximal oxygen uptake (%VO2max) and percentage of ventilatory threshold (%VT). As renal clearance parameters, para-aminohippurate clearance (CPAH) and inulin clearance (CIN) were measured by the continuous infusion technique. Indicators of renal hemodynamics during exercise were the percentage of CPAH, CIN and filtration fraction (FF) at rest. Plasma norepinephrine (NE), plasma epinephrine (E) and plasma renin activity (PRA) were measured. The best regression models between renal clearance parameters and exercise intensity were selected using Akaike's information criterion (AIC). 1) The renal clearance parameters used during exercise were %CPAH, which determined the cubic regression model and %CIN, which determined the quadratic regression model as the exercise intensity increased using AIC. 2) The percentage of maximal oxygen uptake at the onset of decrease in %CPAH and %CIN were 35 and 49%VO2max, respectively, while %CPAH and %CIN began to decrease at 75 and 105%VT, respectively. Intensity of exercise at the onset of increase in %FF was 49%VO2max or 106%VT. 3) The renal clearance parameters during exercise decreased linearly as NE, E and PRA increased. The increase in NE contributed mainly to a change in renal clearances shown by multiple regression analysis. The above results suggest that the relationship among renal plasma flow (RPF), glomerular filtration rate (GFR) and exercise intensity were demonstrated by the cubic regression model and quadratic regression model using AIC, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Membership of faint stars in the globular cluster M3

AbstractA proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). A photographic B,V photometry and star counts on the deepest plates were carried out. With a limiting magnitude of about B = 21.4 proper motions with an accuracy from 2 to 3 mas/yr have been obtained for stars with B 19. The proper motions were determined using a stepwise regression method with 3rd order polynomials in the plate‐to‐plate solutions with about 2000 reference galaxies. The results which were corrected for systematic errors dependent on position and magnitude of the stars were used for the determination of membership probabilities. We also looked for possible internal motions of M3.

Membership and Internal Motions of Faint Stars in the Globular Cluster M 3

A proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M 3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). With a limiting magnitude of B = 21, proper motions of 2 to 3 mas/yr accuracy have been obtained for stars with B &amp;lt; 19. The proper motions were determined applying a stepwise regression method with 3rd order polynomials in the plate-to-plate solutions with about 2000 reference galaxies. We used the results for the determination of membership probabilities and looked for internal motions of M 3.

Exact Solutions for Free Vibration in an Asymmetrical Duffing Equation

An algorithm is proposed for determining the exact solutions for free vibration in an asymmetrical Duffing oscillator. The system is composed of a spring function of the Duffing type (with linear and cubic terms with respect to displacement) accompanied by a constant force. It is reduced from the most comprehensive 3rd-order polynomial having arbitrary terms from a constant to the 3rd power. By employing a bilinear transformation, the system is successfully converted into a regular Duffing equation whose exact solutions already exist and are abstracted here. The whole procedure of obtaining the present solution is summarized in a flow chart. Numerical values of conversion constants, skeleton curves and waveforms are computed and illustrated for the typical cases of asymmetrical (hard, soft and snap-through) spring systems. It is demonstrated that the skeleton curves and waveforms are asymmetrical and that some of them exhibit multivalued responses for a given frequency.