Linear Function Of Time Research Articles

Ultrasonic agglomeration of model flour systems: Process parameter-product physico-thermal property relationships.

Ultrasonic compression was applied to wheat flour to create an agglomerated and compacted model food system. This novel process combines physical compression with ultrasonic vibration to permanently weld particles together, thereby producing a robust compact. Fundamental relationships among operating parameters, energy imparted to the specimens, and physical properties of the agglomerated products were developed. Integrated agglomeration energy was determined to be a linear function of percent maximum horn amplitude and ultrasonication time, and integrated energy in turn influenced product physical properties, such as density and fracture strength, in highly significant linear relationships. Microscopic, computer tomographic, and differential scanning calorimetric analyses confirmed progressive compaction of and thermal stability changes in the flour matrix with increased processing energy. Specimens agglomerated at higher energy levels were furthermore demonstrated to have higher fracture strength than conventionally (pressure-only) compressed specimens despite similar densities, due to the robust interparticle bridging produced by agglomeration. PRACTICAL APPLICATION: Ultrasonic agglomeration represents a potential improvement over standard compression in the manufacturing of meal-supplementing energy bars. Ultrasonic agglomeration effectively adheres particles together without incorporation of low-nutrient- density syrups and binders. Agglomerated and compacted products also have superior mechanical stability, which can improve texture and physical stability during product handling.

Optimizing a supply chain problem with nonlinear penalty costs for early and late delivery under generalized lead time distribution

This article presents a tangible vendor–buyer cooperative strategy that benefits both, the vendor and the buyer where the demand is deterministic constant, and the delivery lead time follows a general distribution. To build a realistic coordination mechanism, a delivery tolerance time range is specified beyond which two different types of nonlinear penalty costs termed as an early delivery penalty cost and late delivery penalty cost are assessed. Shortages are allowed for a short time-span. The penalty costs are taken as a product of a linear function of delivery lead time and a nonlinear function of the delivery lot size. The problem is formulated as a multi-variable mixed-integer nonlinear programming (MINLP) problem and the objective of this research is to achieve the minimum integrated expected cost where decision variables are: reorder point, delivery lot size, number of deliveries, and delivery time thresholds. Since closed-form solutions are not immediately obtained, different search procedures are employed to resolve issues relating to an integer solution. Numerical results are provided for uniform, exponential and normal distributions of delivery lead time to establish the general model.

PENGARUH DESAIN KEMASAN TERHADAP KEPUASAN PELANGGAN UMKN SAKUKATA.CO SALATIGA

The purpose of this research is to promote t-shirt products from Sakukata.co, and to increase customer satisfaction with packaging design using the QFD method. This type of research is quantitative research. The population in this research are customers who have purchased Sakukata.co products at least once. The sample of this research was selected using Linear Time Function and obtained 40 respondents. This study used primary data from Sakukata.co and questionnaires, the data were analyzed using the Quality Function Deployment (QFD) method.The packaging attributes at Sakukata.co consist of the design, dimensions, capacity, shape, strength, and durability of the packaging. The Respon Teknis that must be in Sakukata.co is the packaging design is modern, simple, informative, elegant, and identical to Sakukata.co. The dimensions of the packaging are the same size as the product and can accommodate additional items for souvenirs (during the promo). Maximum packing capacity for 2 products. Ergonomic, and easy to open and close. The packaging material is not easily damaged, and can protect the product when it rains. Packaging design for primary, secondary and tertiary packaging.The results of the partial or simultaneous regression test show that the packaging attributes have a significant effect on customer satisfaction..

Slices of the Anomalous Phase Cube Depict Regions of Sub- and Super-Diffusion in the Fractional Diffusion Equation

Fractional-order time and space derivatives are one way to augment the classical diffusion equation so that it accounts for the non-Gaussian processes often observed in heterogeneous materials. Two-dimensional phase diagrams—plots whose axes represent the fractional derivative order—typically display: (i) points corresponding to distinct diffusion propagators (Gaussian, Cauchy), (ii) lines along which specific stochastic models apply (Lévy process, subordinated Brownian motion), and (iii) regions of super- and sub-diffusion where the mean squared displacement grows faster or slower than a linear function of diffusion time (i.e., anomalous diffusion). Three-dimensional phase cubes are a convenient way to classify models of anomalous diffusion (continuous time random walk, fractional motion, fractal derivative). Specifically, each type of fractional derivative when combined with an assumed power law behavior in the diffusion coefficient renders a characteristic picture of the underlying particle motion. The corresponding phase diagrams, like pages in a sketch book, provide a portfolio of representations of anomalous diffusion. The anomalous diffusion phase cube employs lines of super-diffusion (Lévy process), sub-diffusion (subordinated Brownian motion), and quasi-Gaussian behavior to stitch together equivalent regions.

Intense Quench Process in Slow Agitated Water Salt and Polymer Solutions

In the paper it is shown that quenching in slow agitated water salt solution of optimal concentration and in low concentration of inverse solubility polymers is intensive quenching creating maximal temperature gradients at the beginning of cooling. The evidence to support such idea were collected by analyzing quenching process in liquid media where any film boiling process was completely absent. In this case, surface temperature at the beginning of cooling drops closely to saturations temperature of a liquid within the interval 1–2 seconds, independently on nature of water solution, and then during transient nucleate boiling process maintains at the level of boiling point of a liquid which is often called self–regulated thermal process. The computer modeling of such cooling processes provided Kondrat’ev numbered Kn which are strongly linear function of time. At the beginning of cooling Kondrat’ev number is almost equal to 1 while average Kondrat’ev number Kn≥0.8. According to US Patent, intensive quenching starts when Kn=0.8. Based on achieved results, it is possible to perform intensive quenching in slow agitated of low concentration water salt and polymer solutions, usually initiated by hydrodynamic emitters. Along with liquid agitation, emitters generate resonance wave effect which destroys film boiling processes making cooling very uniform and intensive. The proposed IQ process works perfectly when martensite starts temperature Ms>Ts. If saturation temperature Ts≥Ms, intensive austempering process via cold liquids can be successfully performed to replace slow cooling of molten salts and alkalis by intensive quenching in liquid media.

A Pneumatic Generator Based on Gas-Liquid Reversible Transition for Soft Robots

The soft robots actuated by pressure, cables, thermal, electrosorption, combustion and smart materials are usually faced with the problems of poor portability, noise, weak load capacity, small deformation and high driving voltages. In this paper, a novel pneumatic generator for soft robots based on the gas-liquid reversible transition is proposed, which has the advantages of large output force, easy deformation, strong load capacity and high flexibility. The pressure of the pneumatic generator surges or drops flexibly through the reversible transformation between liquid and gas phase, making the soft actuator stretch or contract regularly, without external motors, compressors and pressure-regulating components. The gas-liquid reversible-transition actuation process is modeled to analyze its working mechanism and characteristics. The pressure during the pressurization stage increases linearly with a rate regulated by the heating power and gas volume. It decreases exponentially with the exponential term as a quadratic function of time at the fast depressurization stage, while with the exponential term as a linear function of time at the slow depressurization stage. The drop rate can be adjusted by changing the gas volume and cooling conditions. Furthermore, effectiveness has been verified through experiments of the prototype. The pressure reaches 25 bar with a rising rate of +3.935 bar/s when 5 mL weak electrolyte solution is heated at 800 W, and the maximum depressurization rate in air cooling is –3.796 bar/s. The soft finger actuated by the pneumatic generator can bend with an angular displacement of 67.5°. The proposed pneumatic generator shows great potential to be used for the structure, driving and sensing integration of artificial muscles.

An Eulerian-Lagrangian discontinuous Galerkin method for transport problems and its application to nonlinear dynamics

We propose a new Eulerian-Lagrangian (EL) discontinuous Galerkin (DG) method formulated by introducing a modified adjoint problem for the test function and by performing the integration of PDE over a space-time region partitioned by time-dependent linear functions approximating characteristics. The error incurred in characteristics approximation in the modified adjoint problem can then be taken into account by a new flux term, and can be integrated by method-of-line Runge-Kutta (RK) methods. The ELDG framework is designed as a generalization of the semi-Lagrangian (SL) DG method and classical Eulerian RK DG method for linear advection problems. It takes advantages of both formulations. In the EL DG framework, characteristics are approximated by a linear function in time, thus shapes of upstream cells are quadrilaterals in general two-dimensional problems. No quadratic-curved quadrilaterals are needed to design higher than second order schemes as in the SL DG scheme. On the other hand, the time step constraint from a classical Eulerian RK DG method is greatly mitigated, as it is evident from our theoretical and numerical investigations. Connection of the proposed EL DG method with the arbitrary Lagrangian-Eulerian (ALE) DG is observed. Numerical results on linear transport problems, as well as the nonlinear Vlasov and incompressible Euler dynamics using the exponential RK time integrators, are presented to demonstrate the effectiveness of the ELDG method.

Economic Value and Perception of Visitors Mangrove Bee Jay Bakau Resort (BJBR) Probolinggo, East Java

The concept economic value is based on availability paying (Willingness to pay) a person to consume goods and services produced by natural resource or the environment.The purpose this study was to analyze characteristics of mangrove attractions, characteristics of visitors, visitor perceptions of sapta charm, and estimate the economic value in BeeJay Bakau Resort Probolinggo. Descriptive research with data collection methods including interviews, observation, documentation and questionnaires. The sampling method uses accidental sampling technique and determination of the number samples using the linear time function formula. For the dependent variable that is number of requests for visits to mangrove tourism and independent variables namely travel costs, distance traveled, education level, income level, age, and working day (HOK). The result of the analysis shows that the visitor's perception of sapta charm in the mangrove tourist attraction which dominates is the friendly aspect of 34.25% while the economic value is IDR 638,287,712,178/year and the total value of the receipts is IDR 4,200,000,000. Suggestions in order increase the potential tourism there because the economic value is higher than value of acceptance as well as research on the aspect of charm so that the development of tourist objects is in line with what visitors want.

Long-Term Immersion Corrosion of Irons and Steel in Seawaters with Calcareous Deposition

The marine immersion corrosion of irons and steel under calcareous deposition (principally calcium carbonate) is known to be relatively low for shorter exposures (e.g., a few years). Herein the effect of calcareous deposition on corrosion is considered for exposures up to 1,300 y. The data are derived from archaeological steel and iron shipwrecks, cast iron cannons and cannonballs, and wrought iron anchors in locations where there was direct evidence, in and on the corrosion products, of calcareous deposition. Such deposition promotes formation of calcium and ferrous carbonate layers of low permeability on and within rusts. These tend to inhibit both early and long-term corrosion rates. The data show that up to about 200 y exposure corrosion losses as a function of time can be approximated closely by a linear function of time. Longer exposures follow a moderate power-law function, consistent with diffusion considerations. Comments are made about the likely interplay between calcareous deposition and microbiological corrosion.

Integrated three layer supply chain inventory model for price sensitive and time dependent demand with suggested retail price by manufacturer

This paper presents an integrated three layer supply chain policy for multi-channel and multi-echelon consisting manufacturer, distributors and retailers as supply chain members. The demand of retailers end is considered as linear function of time and retail price. The average net profit function per unit time is derived for each supply chain member which are based on demand of retailer's end. Since holding cost of goods/inventory is expensive in developed areas, we have introduced a new concept to share holding cost among distributors and retailers. We have optimized lot size, retailing price and replenishment time interval for retailers. We have also optimized initial inventory level and wholesale price for distributors and manufacturer respectively. This study is performed in two different categories one is decentralized and other is centralized scenario. The profit function of each supply chain members has been derived and shown as a concave function with respect to decision variables. More over propositions and results are made to illustrate the proposed model and we have sensitive analyzed it with numerical example.

Fast reconstruction of time-dependent market volatility for European options

This paper presents a robust and fast numerical algorithm to reconstruct the implied volatility as a piecewise linear function of time. This is done from a set of market observations in the Black–Scholes world. We use a fully implicit finite difference scheme to solve the partial differential equations. To find the time-dependent volatility function, we minimize the cost function defined as the sum of the squared errors between the theoretical prices and the prices observed on the market. On the last time step, right before each maturity, we apply a decomposition of the numerical option value with respect to the volatility which increases the stability and the solvability of the problem considered. We employ a predictor–corrector technique due to the non-uniqueness of the volatility function minimizer. The paper is concluded with profound numerical experiments with synthetic and real market data.

Trend and nonstationary relation of extreme rainfall: Central Anatolia, Turkey

The frequency of extreme rainfall occurrence is expected to increase in the future and neglecting these changes will result in the underestimation of extreme events. Nonstationary extreme value modelling is one of the ways to incorporate changing conditions into analyses. Although the definition of nonstationary is still debated, the existence of nonstationarity is determined by the presence of significant monotonic upward or downward trends and/or shifts in the mean or variance. On the other hand, trend tests may not be a sign of nonstationarity and a lack of significant trend cannot be accepted as time series being stationary. Thus, this study investigated the relation between trend and nonstationarity for 5, 10, 15, and 30 min and 1, 3, 6, and 24 h annual maximum rainfall series at 13 stations in Central Anatolia, Turkey. Trend tests such as Mann–Kendall (MK), Cox–Stuart (CS), and Pettitt’s (P) tests were applied and nonstationary generalized extreme value models were generated. MK test and CS test results showed that 33% and 27% of 104 time series indicate a significant trend (with p < 0.01–p < 0.05–p < 0.1 significance level), respectively. Moreover, 43% of time series have outperformed nonstationary (NST) models that used time as covariate. Among five different time-variant nonstationary models, the model with a location parameter as a linear function of time and the model with a location and scale parameter as a linear function of time performed better. Considering the rainfall series with a significant trend, increasing trend power may increase how well fitted nonstationary models are. However, it is not necessary to have a significant trend to obtain outperforming nonstationary models. This study supported that it is not necessarily time series to have a trend to perform better nonstationary models and acceptance of nonstationarity solely depending on the presence of trend may be misleading.

Mechanically Assisted Neurorehabilitation: A Novel Six-Bar Linkage Mechanism for Gait Rehabilitation.

Repeated and intensive gait training can improve muscle strength and movement coordination of patients with neurological or orthopedic impairments. However, conventional physical therapy by a physiotherapist is laborious and expensive. Therefore, this therapy is not accessible for the majority of patients. This paper presents a six-bar linkage mechanism for human gait rehabilitation with a natural ankle trajectory. Firstly, a six-bar linkage mechanism is selected as the original mechanism to construct a gait rehabilitation device. Then the ankle trajectory is formulated as a function of the crank angle. And the rotation angle of the crank is set as a linear function of time. Therefore, constant speed motor is sufficient to control the mechanism. For the dimensional synthesis, the precise point distances of the gait trajectory and the coupler curve are set as objective functions, with the kinematic constraints including in the optimization procedure. To obtain the optimal structure design parameters, a cooperative dual particle swarm optimization algorithm is developed. The results show that the coupler curve matches well with the gait trajectory. The average distance between the 60 precision points is 3.5 mm.

A spatiotemporal weighted regression model (STWR v1.0) for analyzing local nonstationarity in space and time

Abstract. Local spatiotemporal nonstationarity occurs in various natural and socioeconomic processes. Many studies have attempted to introduce time as a new dimension into a geographically weighted regression (GWR) model, but the actual results are sometimes not satisfying or even worse than the original GWR model. The core issue here is a mechanism for weighting the effects of both temporal variation and spatial variation. In many geographical and temporal weighted regression (GTWR) models, the concept of time distance has been inappropriately treated as a time interval. Consequently, the combined effect of temporal and spatial variation is often inaccurate in the resulting spatiotemporal kernel function. This limitation restricts the configuration and performance of spatiotemporal weights in many existing GTWR models. To address this issue, we propose a new spatiotemporal weighted regression (STWR) model and the calibration method for it. A highlight of STWR is a new temporal kernel function, wherein the method for temporal weighting is based on the degree of impact from each observed point to a regression point. The degree of impact, in turn, is based on the rate of value variation of the nearby observed point during the time interval. The updated spatiotemporal kernel function is based on a weighted combination of the temporal kernel with a commonly used spatial kernel (Gaussian or bi-square) by specifying a linear function of spatial bandwidth versus time. Three simulated datasets of spatiotemporal processes were used to test the performance of GWR, GTWR, and STWR. Results show that STWR significantly improves the quality of fit and accuracy. Similar results were obtained by using real-world data for precipitation hydrogen isotopes (δ2H) in the northeastern United States. The leave-one-out cross-validation (LOOCV) test demonstrates that, compared with GWR, the total prediction error of STWR is reduced by using recent observed points. Prediction surfaces of models in this case study show that STWR is more localized than GWR. Our research validates the ability of STWR to take full advantage of all the value variation of past observed points. We hope STWR can bring fresh ideas and new capabilities for analyzing and interpreting local spatiotemporal nonstationarity in many disciplines.

Minimum energy optimal external torque control of human binocular vision

In this paper, we consider eyes from the human binocular system, that simultaneously gaze on stationary point targets in space, while optimally skipping from one target to the next, by rotating their individual gaze directions. The head is assumed fixed on the torso and the rotating gaze directions of the two eyes are assumed restricted to pass through a point in the visual space. It is further assumed that, individually the rotations of the two eyes satisfy the well known Listing’s law. We formulate and study a combined optimal gaze rotation for the two eyes, by constructing a single Riemannian metric, on the associated parameter space. The goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval [0, 1]. The cost function we choose is the total energy, measured by the L^2 norm, of the six external torques on the binocular system. The torque functions are synthesized by solving an associated ‘two-point boundary value problem’. The paper demonstrates, via simulation, the shape of the optimal gaze trajectory of the focused point of the binocular system. The Euclidean distance between the initial and the final point is compared to the arc-length of the optimal trajectory. The consumed energy, is computed for different eye movement chores and discussed in the paper. Via simulation we observe that certain eye movement maneuvers are energy efficient and demonstrate that the optimal external torque is a linear function in time. We also explore and conclude that splitting an arbitrary optimal eye movement into optimal vergence and version components is not energy efficient although this is how the human oculomotor control seems to operate. Optimal gaze trajectories and optimal external torque functions reported in this paper is new.

Understanding and monitoring the evolution of the Covid-19 epidemic from medical emergency calls: the example of the Paris area

We portray the evolution of the Covid-19 epidemic during the crisis of March–April 2020 in the Paris area, by analyzing the medical emergency calls received by the EMS of the four central departments of this area (Centre 15 of SAMU 75, 92, 93 and 94). Our study reveals strong dissimilarities between these departments. We show that the logarithm of each epidemic observable can be approximated by a piecewise linear function of time. This allows us to distinguish the different phases of the epidemic, and to identify the delay between sanitary measures and their influence on the load of EMS. This also leads to an algorithm, allowing one to detect epidemic resurgences. We rely on a transport PDE epidemiological model, and we use methods from Perron–Frobenius theory and tropical geometry.

Labor Productivity in France: Is the Slowdown of its Growth Inevitable or are there Levers to fight it?

Labour productivity in most advanced countries has slowed in successive stages since the 1970’s and, after the 2008 crisis, it has reached its lowest level since World War II. Here we analyze the trend evolution of the aggregate labor productivity per hour worked in France, over the last four decades, with two main questions. 1) Is the slowdown of labor productivity growth a process which began far before the Great Recession and should it continue with just temporary yet persistent effects of the 2008 crisis and 2) are there levers to reverse the current trend? We proceed in two steps. First, the trend (log) productivity is described as a deterministic piecewise linear function of time, involving so-called structural breaks, and, second, without breaks, as a linear function of fundamentals derived from an augmented growth model including Human capital. We propose a thorough econometric investigation with multiple robustness analyses involving sector-specific analyses. The structural specifica-tion we retain is able to explain the evolution of labor productivity over the last four decades. The accumulation of human capital has been the main driver of productivity growth over the period of interest while France is close to the technological frontier.

Predictive model for stress relaxation behavior of glassy polymers based on variable‐order fractional calculus

In this article, a novel constitutive model using fractional calculus is developed to capture the stress relaxation behavior of glassy polymers, where a variable‐order differential operator based on Marchaud fractional derivative is adopted. To assess the validity of the proposed model, a series of stress relaxation tests of the representative glassy polymer, poly(ethylene glycol‐co‐1,4‐cyclohexanedimethanol terephthalate), are conducted, and the stress responses of the specimens under different ambient temperatures are obtained. In view of the basic theory of fractional viscoelasticity, the varying order is assumed to bea function of time. Through the comparison of the fitting effect and reasonability of four kinds of order function based on the experimental data, it is concluded that the linear order function of time is suitable for our model which shows high accuracy. Moreover, the physical significance of order function is analytically derived, and the rising order is found to have a direct connection with the continuous softening of polymers during relaxation. Deeper investigations manifest that high ambient temperature accelerates the material softening, and the change of microstructures inside polymers could be reflected by the varying order, which is possible to provide a new perspective on manufacturing proper polymers with excellent resistance to stress relaxation.

ANALISIS KEPUASAN KONSUMEN TERHADAP PRODUK KERIPIK SALAK UMKM SALAK CRISTAL DI KECAMATAN TURI KABUPATEN SLEMAN YOGYAKARTA

UMKM Salak Cristal is an agro-industry that is engaged in processing salak into various processed salak products. UMKM Salak Cristal has offline and online sales, but less consumer noticed and marketing strategies. UMKM Salak Cristal is not the only salak manufacture producer in Sleman. Therefore it makes UMKM Salak Cristal need information on customer satisfaction to develop appropriate marketing strategies to know changes in consumer needs and achieve customer satisfaction. Accordingly, researchers need to analyze customer satisfaction to help UMKM Salak Cristal in developing the right marketing strategy. This study aimed to 1) Analyze the level of satisfaction with salak chips at UMKM Salak Cristal Turi District, Sleman Regency, Yogyakarta; 2) Determine the marketing strategies that can be done in UMKM Salak Cristal Turi District, Sleman Regency, Yogyakarta. The method of this research used survey method and the sampling method used in this study was the Non-probability sampling method with the accidental sampling technique. A total of 100 respondents were calculated using a linear time function formula. The methods of this research are used Important Performance Analysis (IPA) and Customer Satisfaction Index (CSI). The results showed that: 1) Customer satisfaction to salak chips product in UMKM Salak Cristal is on the criterion of satisfaction, 2) Product attributes that must be prioritized to be improved are taste variations, sales and online promotions, store locations, employee uniforms, neat-looking employees, payment processing, displays adjust of products, and product price tags.

Novel numerical method for heat conduction using superposition of exact solutions

A novel formulation for numerical solution of heat conduction problems using superposition of exact solutions (SES) to represent temperature on sub-elements of a region is described and demonstrated. A simple 1-D linear problem is used to describe the method and highlight potential benefits; however, extensions to higher geometric dimensions and linearization for temperature-dependent properties are possible. Significant new features of this method which are not part of conventional approaches are: local functions for temperature are both time- and space-dependent; both heat flux and temperature at the boundaries of each element have continuous representation; temperature and heat flux can be evaluated at every location in the domain; and heat fluxes on both internal and external boundaries are represented as linear functions of time. The SES method is validated against several exact solutions for the linear case (constant thermophysical properties) and is shown to have accuracy orders of magnitude greater than conventional Crank-Nicolson method. Extension to higher geometries and temperature-dependent properties are discussed.