Simulation-Models for the Phenological Development of Mythimna-Convecta (Walker) (Lepidoptera, Noctuidae)

1990 ◽  
Vol 38 (6) ◽  
pp. 649 ◽  
Author(s):  
G Mcdonald
Keyword(s):  
Linear Model ◽  
Simulation Models ◽  
Sine Wave ◽  
Linear Functions ◽  
Published Data ◽  
Field Development ◽  
Development Rates ◽  
Threshold Temperatures ◽  
Non Linear ◽  
Fluctuating Temperatures

Larvae of armyworm, Mythimna convecta, were reared under fluctuating temperatures (1-7-degrees; 3-13-degrees; 7-17-degrees; 11-24-degrees; 31-39-degrees-C). Data from these trials were combined with previsouly published data derived from constant-temperature studies (ranging from 15-degrees to 33-degrees-C) to model the effects of temperature on development rate. Temperature-dependent development rates for each of eight immature stages were described by one of three non-linear functions and by a linear model modified to improve the performance about the lower and upper temperature extremes. At the lower and upper thermal limits (< 11-degrees-C and > 33-degrees-C) of the species, survival of larvae under fluctuating temperatures was greater than recorded in previously published studies under equivalent constant temperatures. A serious constraint on fitting a model to the later larval instars was the inconsistent appearance of a seventh instar. The two sets of models were evaluated against field development in three winter and one summer experiments. The modified linear model, with capacity to manipulate predicted development at threshold temperatures, provided a marginally better prediction than did the non-linear model. The sine wave method for estimating diurnal temperatures from minimum and maximum temperatures was shown to produce overestimates of development rates. A correction factor for the seasonal conditions in western Victoria was provided.

Effect of Temperature on Development Rate, Survival and Fecundity of Cotton Tipworm, Crocidosema-Plebejana Zeller (Lepidoptera, Tortricidae)

1991 ◽  
Vol 39 (2) ◽  
pp. 191 ◽  
Author(s):  
JG Hamilton ◽  
MP Zalucki
Keyword(s):  
Linear Model ◽  
Development Rate ◽  
Population Increase ◽  
Effect Of Temperature ◽  
Direct Result ◽  
Immature Stages ◽  
Optimum Temperature ◽  
Development Rates ◽  
Non Linear ◽  
Female Weight

C. plebejana were reared from egg to adult at a range of constant temperatures. At 10-degrees-C no immature stages survived. Development rates increased over the temperature range 14-34-degrees-C; these were simulated with a non-linear model. Females emerged before males. Fecundity decreased with increased rearing temperature as a direct result of reduced adult female weight. At 34-degrees-C development rate and survival were reduced and all eggs laid were infertile. Optimum temperature for population increase was 28-degrees-C. Validation of a non-linear model for development rate shows that the species of host-plant affects mean development rates of tipworm. Although 5.3 tipworm generations are possible on cotton annually, only one occurs; reasons for this are suggested.

Computational Issues Associated With Gear Rattle Analysis: Part II — Evaluation Criteria for Numerical Algorithms

1992 ◽  
Author(s):  
R. C. Barlow ◽  
C. Padmanabhan ◽  
Rajendra Singh
Keyword(s):  
Linear Model ◽  
Evaluation Criteria ◽  
Numerical Algorithms ◽  
Simulation Models ◽  
Physical Systems ◽  
Non Linear ◽  
Integration Algorithms ◽  
Domain Integration ◽  
Gear Rattle ◽  
Reliable Methods

Abstract The main focus of this study is to establish evaluation criteria for direct time domain integration algorithms used to solve gear rattle type problems. Such criteria may be used to identify specific numerical problems encountered. The ultimate goal obviously is to find reasonably accurate and reliable methods of solution for such physical systems. Six case studies of increasing complexity, linear to highly non-linear, are solved using well known algorithms. The solutions to the linear model are verified by using analytical results. Non-linear model solutions as yielded by different algorithms are compared qualitatively and quantitatively. Several non-linear simulation models have been validated by comparing predictions with experimental data and results available in the literature.

scholarly journals Influence of the Porosity of Polymer Foams on the Performances of Capacitive Flexible Pressure Sensors

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1968 ◽  
Author(s):  
Sylvie Bilent ◽  
Thi Hong Nhung Dinh ◽  
Emile Martincic ◽  
Pierre-Yves Joubert
Keyword(s):  
Experimental Data ◽  
Linear Model ◽  
Dielectric Material ◽  
Pressure Sensors ◽  
Volume Ratio ◽  
Measurement Range ◽  
Polymer Foams ◽  
First Order ◽  
Non Linear ◽  
Flexible Pressure Sensors

This paper reports on the study of microporous polydimethylsiloxane (PDMS) foams as a highly deformable dielectric material used in the composition of flexible capacitive pressure sensors dedicated to wearable use. A fabrication process allowing the porosity of the foams to be adjusted was proposed and the fabricated foams were characterized. Then, elementary capacitive pressure sensors (15 × 15 mm2 square shaped electrodes) were elaborated with fabricated foams (5 mm or 10 mm thick) and were electromechanically characterized. Since the sensor responses under load are strongly non-linear, a behavioral non-linear model (first order exponential) was proposed, adjusted to the experimental data, and used to objectively estimate the sensor performances in terms of sensitivity and measurement range. The main conclusions of this study are that the porosity of the PDMS foams can be adjusted through the sugar:PDMS volume ratio and the size of sugar crystals used to fabricate the foams. Additionally, the porosity of the foams significantly modified the sensor performances. Indeed, compared to bulk PDMS sensors of the same size, the sensitivity of porous PDMS sensors could be multiplied by a factor up to 100 (the sensitivity is 0.14 %.kPa−1 for a bulk PDMS sensor and up to 13.7 %.kPa−1 for a porous PDMS sensor of the same dimensions), while the measurement range was reduced from a factor of 2 to 3 (from 594 kPa for a bulk PDMS sensor down to between 255 and 177 kPa for a PDMS foam sensor of the same dimensions, according to the porosity). This study opens the way to the design and fabrication of wearable flexible pressure sensors with adjustable performances through the control of the porosity of the fabricated PDMS foams.

Analysis of Single Buffer Random Polling System With State-Dependent Input Process and Server/Station Breakdowns

2018 ◽  
Vol 9 (1) ◽  
pp. 22-50 ◽  
Author(s):  
Thomas Y.S. Lee
Keyword(s):  
Steady State ◽  
Linear Model ◽  
Repair Process ◽  
Polling System ◽  
Steady State Analysis ◽  
Relaxation System ◽  
Polling Model ◽  
State Dependent ◽  
Non Linear ◽  
State Analysis

Models and analytical techniques are developed to evaluate the performance of two variations of single buffers (conventional and buffer relaxation system) multiple queues system. In the conventional system, each queue can have at most one customer at any time and newly arriving customers find the buffer full are lost. In the buffer relaxation system, the queue being served may have two customers, while each of the other queues may have at most one customer. Thomas Y.S. Lee developed a state-dependent non-linear model of uncertainty for analyzing a random polling system with server breakdown/repair, multi-phase service, correlated input processes, and single buffers. The state-dependent non-linear model of uncertainty introduced in this paper allows us to incorporate correlated arrival processes where the customer arrival rate depends on the location of the server and/or the server's mode of operation into the polling model. The author allows the possibility that the server is unreliable. Specifically, when the server visits a queue, Lee assumes that the system is subject to two types of failures: queue-dependent, and general. General failures are observed upon server arrival at a queue. But there are two possibilities that a queue-dependent breakdown (if occurs) can be observed; (i) is observed immediately when it occurs and (ii) is observed only at the end of the current service. In both cases, a repair process is initiated immediately after the queue-dependent breakdown is observed. The author's model allows the possibility of the server breakdowns/repair process to be non-stationary in the number of breakdowns/repairs to reflect that breakdowns/repairs or customer processing may be progressively easier or harder, or that they follow a more general learning curve. Thomas Y.S. Lee will show that his model encompasses a variety of examples. He was able to perform both transient and steady state analysis. The steady state analysis allows us to compute several performance measures including the average customer waiting time, loss probability, throughput and mean cycle time.

Solvent Polarity Studies of the Water+t-Butyl Alcohol and Water+t-Butylamine Binary Systems With the Solvatochromic Dyes Nile Red and Pyridinium-N-phenoxide Betaine, Refractometry and Permittivity Measurements

1994 ◽  
Vol 47 (9) ◽  
pp. 1771 ◽  
Author(s):  
PK Kipkemboi ◽  
AJ Easteal
Keyword(s):  
Binary Systems ◽  
Hydrophobic Interactions ◽  
Nile Red ◽  
Solvent Polarity ◽  
Butyl Alcohol ◽  
Linear Functions ◽  
Non Linear ◽  
Organic Cosolvent ◽  
Two Parameters ◽  
Polarity Parameters

The empirical solvent polarity parameters ENR and ET for the solvatochromic compounds Nile Red (1) and pyridinium-N-phenoxide betaine (2), respectively, have been determined as a function of composition for water+t -butyl alcohol and water+t-butylamine binary mixtures, over the whole composition range at 298 K. For both systems the two parameters vary with composition in a strongly non-linear fashion, and the polarity of the mixture decreases with increasing proportion of the organic cosolvent. The non-linear variation of the polarity parameters is attributed to water-cosolvent hydrophobic interactions at low cosolvent contents, and hydrogen-bonding interactions at higher cosolvent contents. Permittivity and refractive index have also been measured at 298 K for both systems, and both properties are strongly non-linear functions of composition.

Separate and/or simultaneous generations of non-linear functions inherent in non-ohmic resistivities

1976 ◽  
Vol 18 (1) ◽  
pp. 51-61
Author(s):  
Yasuhiro Kobayashi∗ ◽  
Masaaki Ohkita ◽  
Michio Inoue ◽  
Masao Nakamura
Keyword(s):  
Linear Functions ◽  
Non Linear
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