Feeding Trajectories Research Articles

Design of Trajectory Planning System for River Crab Farming with Automatic Feeding Boat

The bait feeding of river crab farming needs to be covered evenly on the whole pond. At present, feeding is mainly carried out by manual driving or remote control ship-borne feeding machine on the pond. The feeding accuracy and efficiency are relatively low, and it is difficult to guarantee feeding effect. In view of the above situation, based on the mobile automatic feeding boat equipped with GPS, this paper proposes a complete coverage trajectory planning method with irregular quadrilateral pond, and a trajectory planning system based on SuperMap Objects is designed to generate reciprocating traverse feeding trajectory automatically. The simulation is performed to verify the feasibility of the trajectory planning method. The results show that the trajectory planning system can meet the requirements of automatic and uniform feeding on the crab pond.

Centre cone generation and its force performance in single-point diamond turning

In single-point diamond turning (SPDT), vertical tool centre error owing to the tool feed trajectory is higher or lower than the workpiece centre will result in the conical or cylindrical appearance on the centre of machined surface. Different from the residual centre cylinder under tool below centre error existance, the interference between the tool and the workpiece when tool above centre error exists will cause interference zone around the formed centre cone, which greatly affects the form accuracy of the machined surface and the optical functions it owns. In order to explore the evolution and force performance of the central cone during tool interference, and realize the online identification of tool above centre error, this paper analyzed the relation between the centre structure mophology and the cutting force form under the existence of the tool above centre error. Meanwhile, the influence of the secondary interference between the tool clearance face and the centre cone generated from previous face turning was studied. Then, by establishing the geometric model of the tool clearance face, round platform and centre cone during the turning process, a interference spatial curve model between tool and workpiece was derived. Finally, a force model reflected by the mapping of extrusion area of tool and workpiece was established, whereby the mapping relation between the cutting force and the morphology of the interference zone was further clarified, and the tool above centre error could be online identified based on the cutting force forms. Theoretical and experimental results show an exact correspondence between the cutting force and the morphology of interference zone, the online identification of the tool above centre error can be potentially realized by the established cutting force model, which greatly improves the cutting efficiency of SPDT.

Early Achievement of Enteral Nutrition Protein Goals by Intensive Care Unit Day 4 is Associated With Fewer Complications in Critically Injured Adults.

Although robust randomized controlled trials are lacking, present data suggest that early, adequate nutrition is associated with improved outcomes in critically ill patients. Injured patients are at risk of accumulating significant protein debt due to interrupted feedings and intolerance. Critically injured adults who were unable to be volitionally fed were included in this retrospective review. Data collected included demographics, injury characteristics, number and types of operations, total prescribed and delivered protein and calories during the first 7 days of critical care admission, complications, and outcomes. Group-based trajectory modeling was applied to identify subgroups with similar feeding trajectories in the cohort. There were 274 patients included (71.2% male). Mean age was 50.56 ± 19.76 years. Group-based trajectory modeling revealed 5 Groups with varying trajectories of protein goal achievement. Group 5 fails to achieve protein goals, includes more patients with digestive tract injuries (33%, P = 0.0002), and the highest mean number of complications (1.52, P = 0.0086). Group 2, who achieves protein goals within 4 days, has the lowest mean number of complications (0.62, P = 0.0086) and operations (0.74, P = 0.001). There is heterogeneity in the trajectory of protein goal achievement among various injury pattern Groups. There is a sharp decline in complication rates when protein goals are reached within 4 days of critical care admission, calling into question the application of current guidelines to healthy trauma patients to tolerate up to 7 days of nil per os status and further reinforcing recommendations for early enteral nutrition when feasible.

Extended unit arc length increment interpolation for generalized NURBS curves in multi-axis EDM

Multi-axis electrical discharging machining (EDM) is the main manufacturing approach for shrouded blisks. To maintain a stable discharging, the feedrate of an electrode must be regulated appropriately with respect to a workpiece. The feedrate control in multi-axis EDM is a challenge due to two facts. The first is that the feedrate fluctuations occur at line segment junctions along the feeding trajectory which is expressed in G01 codes. The second is that, with involvement of rotary axes, the feedrate control must consider the nonlinear mapping between the workpiece frame and the machine frame. This paper proposes an extended unit arc length increment interpolation (UALII) for generalized NURBS curves. Given the point coordinates in the machine frame, the coordinates in the workpiece frame can be obtained by the forward kinematics. By using the UALII, the curve parameter is first obtained. To achieve synchronization among involved axes, the curve parameter is substituted into the generalized NURBS curve. Due to the nonlinear mapping, each interpolation of one basic length unit (BLU) can give the axial increments which are more than one BLU. Digital differential analyzer (DDA) is used for a finer interpolation for each axial increment. Machining tests show that the use of UALII for generalized NURBS curves can decrease the machining time by 42.19%, 29.65% and 26.42%, respectively, as compared with the cases of no feedrate planning, the weighted average movement ratio algorithm (WAMRA) and the feedrate post-processing algorithm (FPPA). The extended UALII algorithm can also reduce the electrode wear.

Early infant feeding and body mass index trajectory in the first five years of life

Early infant feeding and body mass index trajectory in the first five years of life

Advanced nonlinear multi-layer process control for autotrophic cultivations

Abstract This paper presents a control architecture suitable for autotrophic cultivations in a stirred tank reactor feeding a gas mixture of H2/CO2/O2. Based on the employed multi-layer structure, for simple gas phase control no metabolic information of the strain is required. A MIMO-PI controller connected to an adaptive feedforward disturbance rejection based on a physical model allows for a gas phase feedback control. Thus, without further knowledge of the autotrophic strain, experiments can be run to generate data and develop a process model including strain specific biological details. Combining both layers, gas phase control and feeding trajectory optimization with the process model, results in a control architecture that is suitable for optimizing the process in a closed-loop.

Completion of thermal runaway criteria: Two new criteria to define runaway limits

Safe operation of thermally sensitive chemical reactors remains a crucial engineering issue. Thermal runaway occurs mainly due to loss of temperature control, and many chemical accidents initiated by thermal runaway can be foreseen by an appropriate analysis of thermal process data. Thermal runaway criteria can be applied to determine the onset of runaway phenomena and safety boundary diagrams can be constructed. However, several runaway criteria exist, which define the runaway-and safe zones differently. In this work nine commonly applied thermal runaway criteria were analyzed and compared based on their critical curves. As a result of this analysis, two new criteria were developed. Reliability of the derived criteria were investigated, where the occurrence of real runaway was determined based on the number of indications applying different criteria. The two new criteria were tested in three general reaction systems and in case a complex problem, where feeding trajectory of fed-batch reactor was optimized applying new criteria as non-linear constraint. One of the new criteria shows the highest reliability in indication of runaway development from all investigated runaway criteria.

Greater Breastfeeding in Early Infancy Is Associated with Slower Weight Gain among High Birth Weight Infants

To examine whether feeding patterns from birth to age 6 months modify the association between birth weight and weight at 7-12 months of age. Longitudinal mixed models were used to examine feeding trajectories across categories of birth weight and weight at 7-12 months of age in 1799 mother-infant dyads enrolled in the Infant Feeding Practices Study II. The percentage of breast milk received and the average daily formula consumption were calculated from birth to 6 months of age. Birth weights were classified as high (≥4000 g) and normal (≥2500 g and <4000 g). Weights at 7-12 months of age were categorized as high (z score >1) or normal (z score ≤1). A secondary analysis was performed using categories defined by birth weight adjusted for gestational age percentiles (>90% and 10th-90th percentile). High birth weight (HBW) infants with high weights at 7-12 months of age demonstrated a rapid decline in the percentage of breast milk feedings compared with HBW infants with normal weights at 7-12 months of age. Normal birth weight infants with high weights at 7-12 months of age received a lower percentage of breast milk and had greater absolute intakes of formula than those with normal weights at 7-12 months of age; these associations did not vary over time. Results were similar when infants were categorized by birth weight percentiles. A lower proportion of breast milk feedings was associated with excess weight at 7-12 months of age in HBW infants. These findings suggest an initial target for obesity prevention programs focusing on the first 6 months after birth.

A learning from demonstration framework for implementation of a feeding task

In this paper, a learning from demonstration (LFD) approach is used to design an autonomous meal-assistance agent. The feeding task is modeled as a mixture of Gaussian distributions. Using the data collected via kinesthetic teaching, the parameters of the Gaussian mixture model (GMM) are learnt using Gaussian mixture regression (GMR) and expectation maximization (EM) algorithm. Reproduction of feeding trajectories for different environments is obtained by solving a constrained optimization problem. In this method we show that obstacles can be avoided by robot’s end-effector by adding a set of extra constraints to the optimization problem. Finally, the performance of the designed meal assistant is evaluated in two feeding scenario experiments: one considering obstacles in the path between the bowl and the mouth and the other without.

Cooperative solving method of chute postures in the bending section of a scraper conveyor

This article proposes a cooperatively analytic solving method that calculates the chute posture in the bending section. The method maintains a good posture of the scraper conveyor during its bending process and solves the feeding trajectory of the shearer accurately and precisely. This method modifies and perfects the existing method to obtain the main parameters of the bending section, including the postures of the chutes and pin rails, and the corresponding extension lengths of the advancing units. A virtual-reality software that can visually simulate this entire operation process under different conditions is developed. Considering the gap between the driving wheel and the pin rails, the relationship between the shearer yaw angle and shearer working trajectory in the feeding stage is investigated for different body lengths. The angular relationship between the left and right driving wheels and the pin rails is also researched. Finally, the proposal is verified in experiments on a test prototype and on physical equipment. This analytic method provides a theoretical basis for the cooperative three-dimension localization of three machines in a fully mechanized coal-mining face, ensuring safe automatic production of the mining face.

Optimization of fed-batch fermentation processes using the Backtracking Search Algorithm

Fed-batch fermentation has gained attention in recent years due to its beneficial impact in the economy and productivity of bioprocesses. However, the complexity of these processes requires an expert system that involves swarm intelligence-based metaheuristics such as Artificial Algae Algorithm (AAA), Artificial Bee Colony (ABC), Covariance Matrix Adaptation Evolution Strategy (CMAES) and Differential Evolution (DE) for simulation and optimization of the feeding trajectories. DE traditionally performs better than other evolutionary algorithms and swarm intelligence techniques in optimization of fed-batch fermentation. In this work, an improved version of DE namely Backtracking Search Algorithm (BSA) has edged DE and other recent metaheuristics to emerge as superior optimization method. This is shown by the results obtained by comparing the performance of BSA, DE, CMAES, AAA and ABC in solving six fed batch fermentation case studies. BSA gave the best overall performance by showing improved solutions and more robust convergence in comparison with various metaheuristics used in this work. Also, there is a gap in the study of fed-batch application of wastewater and sewage sludge treatment. Thus, the fed batch fermentation problems in winery wastewater treatment and biogas generation from sewage sludge are investigated and reformulated for optimization.

Feeding trajectory optimization in fed-batch reactor with highly exothermic reactions

Abstract Process engineers and operators should understand reactor runaway phenomenon to avoid hazard situations and accidents. Reactor runaway occurs when an exothermic reaction takes place in a reactor with insufficient heat transfer area. The reaction rate increases due to the temperature rise, causing a further increase in reaction rate and temperature. Without any safety action, only the reactant consumption limits the maximum temperature. One of the safety actions can be the application of runaway criteria to characterize the safe operating regimes where the optimal operating conditions can be found. This paper presents runaway criteria and the application of these in case of the feeding trajectory optimization of a fed-batch reactor model. The most important runaway criteria and the relations between them are presented, and critical curves of criteria are calculated using a simple dimensionless tubular reactor. The optimal feeding trajectory is determined in case a pilot plant fed-batch reactor using different runaway criteria as a non-linear constraint based on particle swarm optimization and sequential quadratic programming. Designers need to know how they can choose the right criterion, and the results can help with it. Selectivity and profit can be decreased if runaway occurs in a fed-batch reactor, therefore it is important to deal with this problem.

Optimization on cooperative feed strategy for radial–axial ring rolling process of Inco718 alloy by RSM and FEM

During radial–axial ring rolling process, cooperative strategy of the radial–axial feed is critical for dimensional accuracy and thermo mechanical parameters distribution of the formed ring. In order to improve the comprehensive quality of the ring parts, response surface method (RSM) is employed for the first time to optimize the cooperative feed strategy for radial–axial ring rolling process by combining it with an improved and verified 3D coupled thermo-mechanical finite element model. The feed trajectory is put forward to describe cooperative relationship of the radial–axial feed and three variables are designed based on the feed trajectory. In order to achieve multi-objective optimization, four responses including thermo mechanical parameters distribution and rolling force are proposed. Based on the FEM results, RSM is used to establish a response model to depict the function relationship between the objective response and design variables. Through this approximate model, effects of different variables on ring rolling process are analyzed connectedly and optimal feed strategy is obtained by resorting to the optimal chart specific to a constraint condition.

On-line monitoring of substrates and biomass using near-infrared spectroscopy and model-based state estimation for enzyme production by S. cerevisiae

In the early process development, feeding trajectories and cultivation conditions are altered in order to maximise the desired product. This is in contrast to industrial cultivations, where variations are to be eliminated. In order to fully understand and safely run a new process, real-time information are beneficial. Near-infrared spectrometer that are coupled to a fermenter offer the possibility to gather information on-line. The NIR data can be transformed via partial least squares modeling to estimate substrate and biomass concentrations. At low concentrations and under changed cultivation conditions during process development, however, the estimates may differ from reality. This uncertainty may be reduced by integrating biological and physico-chemical knowledge in the on-line estimation. In this contribution, we present a hybrid approach of near-infrared (NIR) spectroscopy and nonlinear model-based state estimation to enable an improved quality in the on-line estimation of substrates and biomass in a yeast cultivation. As only three cultivations are needed for calibration, on-line state estimation is available in the early stage of development for this process. This approach is compared to the use of both methods separately for estimation of biomass, ammonium, glucose, phosphate and ethanol in cultivations of S. cerevisiae.

Modelling the production of soluble hydrogenase in Ralstonia eutropha by on-line optimal experimental design

This paper presents a case study on integrating a new model extension describing the production of the enzyme soluble hydrogenase (SH) into an already existing model by means of on-line optimal experimental design (OED). These investigations were done on the autotrophic cultivation system and process model of Ralstonia eutropha, i.e., a cultivation where aeration by air is replaced by a gas consisting of H2/O2/CO2. Prior to the experiment, three different structures of the new model extension are postulated and coarsely identified. Off-line OED with the best model yields initial feeding trajectories. During the experiment, a repetitive model refinement is performed. This consists of identifying the parameters of the new model extension for all three models, selecting the best model and recalculating optimal feeding trajectories. It is shown that on-line OED in the early modelling stage followed by a manual modelling step results in an acceptable quality of the description of SH production.

Sex-specific effects of protein and carbohydrate intake on reproduction but not lifespan in Drosophila melanogaster.

Modest dietary restriction extends lifespan (LS) in a diverse range of taxa and typically has a larger effect in females than males. Traditionally, this has been attributed to a stronger trade-off between LS and reproduction in females than in males that is mediated by the intake of calories. Recent studies, however, suggest that it is the intake of specific nutrients that extends LS and mediates this trade-off. Here, we used the geometric framework (GF) to examine the sex-specific effects of protein (P) and carbohydrate (C) intake on LS and reproduction in Drosophila melanogaster. We found that LS was maximized at a high intake of C and a low intake of P in both sexes, whereas nutrient intake had divergent effects on reproduction. Male offspring production rate and LS were maximized at the same intake of nutrients, whereas female egg production rate was maximized at a high intake of diets with a P:C ratio of 1:2. This resulted in larger differences in nutrient-dependent optima for LS and reproduction in females than in males, as well as an optimal intake of nutrients for lifetime reproduction that differed between the sexes. Under dietary choice, the sexes followed similar feeding trajectories regulated around a P:C ratio of 1:4. Consequently, neither sex reached their nutritional optimum for lifetime reproduction, suggesting intralocus sexual conflict over nutrient optimization. Our study shows clear sex differences in the nutritional requirements of reproduction in D. melanogaster and joins the growing list of studies challenging the role of caloric restriction in extending LS.

Servo Drive Trajectory Design of Three-Axis Laser Processing System

Three-axis processing of laser inner engraving machine control system can carry on multi-axis linkage control. Furthermore, it ensures multi-axis of high feeding speed and trajectory control of high precision. This article introduces the design of laser inner engraving machine movement control system. The core is a digital integrator of linear interpolation algorithm to generate the desired trajectory and control XYZ axis linkage. Wide speed range of servo motor and position detector resolution is adequate to constitute a half-closed loop drive. With integral separation algorithm being introduced in the controller, the speed of numerical control system, track speed and positioning accuracy are guaranteed in order to achieve optimal specification for dynamic and static characteristics of the whole system.

Understanding decision moments in infant feeding trajectories to improve interventions (119.4)

Behavioral interventions have been used to improve infant and young child feeding (IYCF) with varying success. “Decision moments” (DMs), critical junctures at which caregivers make choices about IYCF are often key intervention targets. The behavior resulting from DMs determines what and how children are fed and thus their longitudinal pattern of feeding or “IYCF trajectory.” In the context of the Alive &amp;amp; Thrive process evaluation in Bangladesh, we aimed to understand behavior at these critical junctures by identifying DMs, characterizing and describing “IYCF trajectory” patterns, and examining the influence of maternal and household capacities (M&amp;amp;HCaps). We conducted longitudinal, in‐depth qualitative interviews (n=89 interviews in n=17 households) with mothers, fathers and grandmothers when the index child was 0‐6 and 7‐11 mo old. NVivo v10 was used for coding and analysis. Households were classified into 9 “IYCF trajectory” patterns based on a biomedical paradigm. “IYCF trajectory” patterns varied widely. DMs clustered at several times: after birth, and at 3‐4, 5‐6, 6‐7, and 7‐8 mo. The most influential M&amp;amp;HCaps included financial and material resources, time, social support, supportive advice and beliefs. We conclude that DMs cluster at multiple times during IYCF trajectories, there is no single normative “IYCF trajectory” that characterizes the population, and interventions to influence critical DMs must identify and remedy inadequate M&amp;amp;HCaps.Grant Funding Source: Alive &amp; Thrive, funded by the Bill &amp; Melinda Gates Foundation &amp; managed by FHI360; NIH(5T32HD007331)

Optimization of fed-batch fermentation processes with bio-inspired algorithms

The optimization of the feeding trajectories in fed-batch fermentation processes is a complex problem that has gained attention given its significant economical impact. A number of bio-inspired algorithms have approached this task with considerable success, but systematic and statistically significant comparisons of the different alternatives are still lacking. In this paper, the performance of different metaheuristics, such as Evolutionary Algorithms (EAs), Differential Evolution (DE) and Particle Swarm Optimization (PSO) is compared, resorting to several case studies taken from literature and conducting a thorough statistical validation of the results. DE obtains the best overall performance, showing a consistent ability to find good solutions and presenting a good convergence speed, with the DE/rand variants being the ones with the best performance. A freely available computational application, OptFerm, is described that provides an interface allowing users to apply the proposed methods to their own models and data.

Exploring the Process of Women’s Infant Feeding Decisions in the Early Postbirth Period

Research indicates that multiple factors are associated with decisions women make about infant feeding, yet few studies have explored the decision-making process. In this article, we present the analysis that produced the core category "deconstructing best," previously reported as part of a grounded theory exploring 37 Australian women's infant feeding experiences and decisions in the first 6 weeks postbirth. We expand on the previous article by detailing and discussing the phases of the infant feeding decision-making process in relation to decision-making theory. Analysis demonstrates the importance of these early weeks in shaping women's infant feeding trajectories. Findings illustrate that information gathering encompassing multiple factors occurred at this time, and that complex and often competing goals were involved in the women's decisions. We suggest that acknowledging and assisting women to meet alternate goals in the postbirth period might help them meet their breastfeeding goals.