Full Factorial Experiment Research Articles

MATHEMATICAL ANALYSIS OF THE SORPTION PROCESS OF MINE WATER PURIFICATION

Contaminated mine water with a large amount of salts makes underground and surface water sources unsuitable for household and drinking needs. Already in 2016, there was a shortage of drinking water in the Rostov region. Water from surface sources does not meet the hygienic requirements for chemical parameters in 36.1% of the samples taken. Water from underground sources in terms of color, turbidity, total hardness, dry residue, content of iron ions, manganese, hydrogen sulfide, nitrates, ammonia, chlorides, sulfates, magnesium, sodium did not meet the required standards in 72.2% of cases. Due to the need for huge expenses for the purification of highly mineralized waters and the poor development of cheap technologies for the neutralization of large volumes, attempts to purify discharged or flowing mine waters to a safe level turn out to be practically fruitless. In this article, studies were carried out to reduce the concentration of dissolved ions of heavy metals (iron, manganese, copper and zinc) in mine wastewater by sorption in a static mode (charring) using rice husk biochar with electromagnetic treatment. The authors proposed a method for pre-treatment of the sorbent from rice husk biochar in an electromagnetic field at a process activation unit. The results of laboratory tests confirmed the high efficiency of the sorbent for the removal of heavy metal ions from mine waters. On the basis of the results obtained, optimization of the sorption purification of mine waters in the mode of carbonization was carried out using the method of mathematical planning of the experiment (full factorial experiment FFE 2k). The factors most influencing the efficiency of mine wastewater treatment from iron and zinc ions have been identified. With a probability of 0.95, the proposed models are adequate, and they can be used to describe the sorption process when using the studied sorbent to remove heavy metal ions (iron, zinc, etc.), while the optimal concentration of the sorbent from rice husks is within 0.5 mg/l. With an increase and decrease in the concentration of the sorbent above the optimal values, the efficiency of sorption decreases, and this affects the iron to a greater extent. In general, the obtained sorbent has a chemical composition similar to that of activated carbon (the most widely used sorbent for water purification), but at the same time it is a cheap production waste, which confirms its efficiency, both technological and economic, when used to purify natural and waste water. With the introduction of the proposed treatment scheme for mine water treatment facilities, it is expected that the concentrations of dissolved heavy metal ions, in particular, iron, zinc, manganese, will decrease to the concentration of the discharge into the reservoir.

Development of a model and optimization of the interaction of factors in the grain malting process and its application in the production of functional beverages

The paper is devoted to the study of the interaction and significance of factors influencing the prediction and optimization of the process of obtaining malt. The object of our research is wheat, barley and rye malt. 33 full factorial experiments were performed, germination period, wetting degree and temperature act as variable factors. At the same time, the amylolytic activity of malt's enzymatic complex and malt's saccharification ability were taken as the response function of the experiment. 27 experiments were carried out with three repetitions in order to check the accuracy of the choice of optimal conditions for the process of obtaining malt, and a regression equation was obtained. According to the least squares method, the regression equations were obtained for approximation of the saccharification ability (SA) and amylolytic activity (AA) values of wheat malt. According to the method of regression analysis, the adequacy of the equations was checked by the Fisher criterion, the statistical significance of their coefficients was checked by the Student's criterion, and the homogeneity of parallel experiments was checked by the Cochrane criterion. The regression model expressing the result of the optimization of the process of obtaining wheat malt is as follows: τ=5.8 days, w=42.2 %, t=15.9 °C; YSA=5.35, YAA=320.0, for barley malt – τ=6.1 days; w=44.1 %; t=17.6 °C; YSA=4.93; YAA=255.2, and for rye malt – τ=4.6 days; w=45.1 %; t=15.0 °C; YSA=8.63; YAA=198.1. In this work, the temperature dependence of the amylolytic activity and saccharifying activity of malt enzymes was also studied. The germination temperature of grains has a maximum effect on the complex of amylolytic enzymes of malts. The research materials can be applied in the production of non-alcoholic and functional beverages

Light more than warming impacts understory tree seedling growth in a temperate deciduous forest

Understanding the distinct impacts of temperature and light on seedling growth is crucial for predicting forest regeneration trajectories under future climate change and forest disturbance. This is because temperature and light can change independently or together, influencing the competitive status of tree seedlings and forest herbs. However, most prior studies tend to explore temperature and light effects either separately or in combination, lacking comprehensive full-factorial designs. Here, we utilized two large-scale full-factorial experiments to explore warming and light effects on tree seedlings growing in mesocosms with herbaceous plants. We found that light increased seedling height, diameter, and biomass, while warming alone had no significant effects. Moreover, we observed that there was an interaction effect between light and warming, where warming increased seedling height, diameter, and biomass under illumination. Understory herbaceous plant cover alone did not affect seedling height, diameter, and biomass, but it decreased seedling biomass when mesocosms were warmed or illuminated. This highlights the importance of considering the indirect negative effects induced by the interaction between forest opening and understory herbaceous plants. By disentangling the effects of increased temperature and light availability on understory seedling height, diameter, and biomass, our results contribute valuable knowledge for future forest management. It is imperative to carefully control the size of the gaps artificially created to facilitate the understory regeneration. Small gaps are recommended considering that the herbaceous plants may interact with both warming and light to negatively affect seedlings.

Hydrolysis Optimization of By-Products from the Potato Processing Industry and Biomethane Production from Starch Hydrolysates

This study aims to investigate the use of Fenton reagents for the efficient hydrolysis of starch, an industrial by-product obtained from the potato processing industry. A full factorial design experiment (FFD) was conducted and a statistical model was developed for simulating the hydrolysis process. The most important factors were the hydrolysis temperature and the amount of H2O2 followed by the interaction of FeSO4·7H2O and temperature. At maximum levels of FeSO4·7H2O (1.00g/L), H2O2 (0.51 g/L), and temperature (70.0 °C), a 99.5% hydrolysis yield was achieved, with a carbohydrate content of 28.65 g/L. Furthermore, analysis of hydrolysis kinetics demonstrated that an increased concentration of FeSO4·7H2O results in a decelerated rate of starch hydrolysis. Moreover, biodegradability tests were carried out to estimate the methane production potential from the produced hydrolysates. The specific methanogenic activity (SMA) was reached at 0.669 ± 0.014 g CH4-COD g−1 VSS day−1 proving the effectiveness of the hydrolysis process and highlighting the potential of industrial starch for bioenergy production. A preliminary cost analysis showed that a small investment for utilizing the starch in an existing wastewater treatment facility of a potato processing company becomes profitable before the end of the 3rd year, obtaining a net present value (NPV) 37.5% higher than that of the current utilization scenario.

Computation offloading for ground robotic systems communicating over WiFi – an empirical exploration on performance and energy trade-offs

ContextRobotic systems are known to perform computation-intensive tasks with limited computational resources and battery life. Such systems might benefit from offloading heavy workloads to the Cloud; however, in some cases, this implies high network traffic that degrades performance and energy consumption.GoalIn this study, we aim at evaluating the impact of different computation offloading strategies on performance and energy consumption in the context of autonomous robots.MethodWe conduct two controlled experiments involving a robotic mission based on the Turtlebot3 robot and ROS 1. The mission consists of three tasks that are recurrent in robotics and good candidates for computation offloading in research, namely, SLAM mapping, navigation stack, and object recognition. Each of the tasks is either executed on board or offloaded in a full-factorial experiment design. The obtained measures are then statistically analyzed.ResultsThe results show that offloading the object recognition task causes a more significant decrease in resource utilization and energy consumption than both SLAM mapping and navigation. However, object recognition affects the volume of network traffic significantly to the extent that it can easily cause network congestion.ConclusionsIn the context of our experiments (i.e., those involving small-scale ground ROS-based mobile robots operating under WiFi networks), offloading object recognition is beneficial in terms of performance and energy consumption. Nevertheless, large network bandwidth needs to be available for object recognition offloading. While the image resolution and frame rate have a significant impact on not only the network traffic but also energy consumption and performance, these parameters need to be carefully set so that the results of this task can be always received in time, which is particularly crucial in real-time systems.

Silicon-based anti-herbivore defense in tropical tree seedlings.

Silicon-based defenses deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding anti-herbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar (Spodoptera frugiperda). Leaf damage was assessed. Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species. Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species.

The Effect of Robot’s Facial Features on Users’ Perception: Evidence from Subjective, Pupillometry, and Electroencephalography Measures

The present study aimed to investigate how facial features, including facial ratio, eye shape, and mouth presence, influence users’ perceptions of social robots in terms of anthropomorphism, trustworthiness, and overall impressions. Using electroencephalogram (EEG) and eye-tracking technologies, we conducted a 2 (face ratio) × 2 (eye shape) × 2 (with or without mouth) full factorial experiment designed within-subject. EEG signals and pupil diameters were recorded while participants viewed images of robots with different facial design features. The results showed that the shape of robot’s eyes significantly influenced users’ perceptions, with round eyes being associated with higher ratings of anthropomorphism, trustworthiness, and overall positivity. Robots with lower facial width-to-height ratios (fWHR) induced smaller average pupil diameters in users than those with high fWHR. Additionally, robots with lower fWHR were perceived as more anthropomorphic, trustworthy and users produced higher theta rhythm when the eye shape was round but did not when it was rectangular. The presence of a mouth led to higher ratings of anthropomorphism rather than trustworthiness and other measures. Overall, the findings highlight the importance of facial features in shaping users’ perceptions of social robots and provide practical implications for designing social robots with anthropomorphic facial features.

Evaluation of Dimensional Characteristics of Conductive Pattern Elements of 3D-Printed Circuit Boards

Introduction. A review of foreign publications on 3D printing methods shows the possibility of their application for the manufacture of printed circuit boards (PCBs), while demonstrating the growth of interest in this field. One of the available methods is fused deposition modeling, which can be used to form substrates with channels for traces. At present, the minimum channel width comprises 100 µm, which corresponds to the 5th class of PCB accuracy. However, there is no data on how to obtain such dimensions or on the magnitude of their deviation from the given nominal values.Aim. To determine the influence of such factors as nozzle diameter and the number of contours on the dimensional characteristics of PCBs (linear dimensions; trace channel width; trace spacing; via diameters).Materials and methods. To obtain linear models, a full factorial experiment was carried out. The influence of the following materials was evaluated – polylactide (PLA), acrylonitrile butadiene styrene (ABS) and glass-filled ABS; slicers – Ultimaker Cura and PrusaSlicer; 3D printers – Picaso 3D Designer Classic 2016 and Hercules Strong 2017; brass nozzle with diameters ∅0.2 and ∅0.4 mm. The possibility of using brass nozzles coated with chemical nickel for printing with glass-filled filaments was considered. The study was conducted using the facilities of the "Center for Additive Technologies" of Bauman Moscow State Technical University.Results. The possibility of manufacturing PCBs up to the 2nd and 3rd accuracy classes using nozzles with a diameter of ∅0.4 and ∅0.2 mm, respectively, was shown. It was found that galvanic deposition of chemical nickel on a ∅0.2 mm brass nozzle makes it possible to increase the PCB wearability when printing with glass-filled filaments. Recommendations are proposed for selecting an optimal combination of nozzle diameter and the number of contours.Conclusion. The conducted analysis of mathematical models shows the significance of such parameters as nozzle diameter and the number of contours. The results can be used when creating new PCB layouts

Optimization of the Technological Process of Dispersing Brass Waste in a Carbon-Containing Environment by Setting up a Full Factorial Experiment

Purpose of research. Optimization of the technological process of dispersing brass waste in a carbon-containing environment by setting up a full factorial experiment.Methods. The electroerosion process of LS58-3 alloy waste was carried out on a patented device, LS58-3 alloy waste (GOST 15527-2004) was used as metal waste. Isopropyl alcohol (GOST 9805-84), which is a carbon-containing medium, was chosen as the working fluid (dispersing medium).Variable parameters during operation of the installation were: the voltage supplied to the electrodes (100...200 V); capacity of discharge capacitors (25...65 μF); discharge frequency 50...100 Hz.When an electric discharge occurs, the electrodes and wastes are instantly destroyed and the smallest powder particles are formed. The granulometric composition of the obtained powder was carried out using the Analysette 22 NanoTec particle size analyzer. The development of a mathematical model of the process of obtaining lead brass powder was carried out by conducting a full factorial experiment of type 23.Results. As a result of mathematical calculations, the maximum value of the optimization output parameter (average particle size) was determined, which was 23.8 μm at the following values of the factors (dispersion modes): the voltage supplied to the electrodes is 200 V, the discharge frequency is 100 Hz, and the capacity of the discharge capacitors is 65 μF.Conclusion. On the basis of the obtained results of studies and calculations, it is possible to conclude that by changing the operating modes of the EDM installation, it is possible to obtain powders of different sizes. The voltage applied to the electrodes and the capacity of the discharge capacitors have the greatest influence on the particle size of the resulting charge. When the values of these parameters increase, the mass yield of the powder increases, which directly depends on the size of the obtained particles.The obtained regression equation makes it possible to determine at which operating modes of the installation it is possible to obtain powder of a given particle size.

Research Regarding the Dimensional Precision of Electrical Steel Strips Machined by Waterjet Cutting in Multilayer Packages

Manufacturing parts made of thin steel in small batches is a challenging task in terms of reaching the proper balance between the productivity, the cost, and the dimensional precision. This paper presents the results of experimental research about manufacturing electrical steel thin parts using abrasive waterjet cutting. For a certain increase of productivity and a more efficient process, the parts were cut using multilayer packages of steel strips. The main objective was to analyze the influence of the number of layers on the dimensional precision of parts. Preliminary tests were performed, followed by a full factorial experiment using two independent parameters, the number of layers and the traverse speed. The parts were measured on a noncontact vision measurement machine and mathematical models were determined to predict the parts deviations depending on the independent parameters used. A practical validation of the models was performed. The main conclusion is that the number of layers has a certain influence on the accuracy of dimensions, but this influence can be predicted with a satisfactory level of confidence using mathematical models.

Exploration of effects by the ‘alum-glue solution’ on Xuan paper degradation using a 23 factorial design experiment

In the traditional Chinese conservation mounting process, it is well acknowledged that the alum-glue solution, composed of potassium aluminum sulfate [KAl(SO4)2·12H2O], gelatin, and water, is commonly used for paper sizing. In this study, its adverse effects when prepared in different ratios on the contemporary Xuan paper are explored, demonstrating certain negative influences on material properties and paper durability. We primarily characterized an extra-pure Xuan paper as a reference sample. Then, a 23 full factorial experiment was designed and performed to explore the effects of the three factors, i.e., KAl(SO4)2·12H2O (denoted as alum), animal glue or gelatin (denoted as glue), and water contents on rates of paper degradation [kΔ(1/DP)] and color changes (kΔL and kΔb). The results show that the unsized extra-pure Xuan paper sample has good stability due to appreciable alkaline reserve, weakly alkalinity, and no presence of transition metals. Fourier transform infrared (FTIR) spectra and scanning electron microscope (SEM) images demonstrate the presence of sizing. Given that the alum-glue solution has been widely used in paper conservation, the results in this study demonstrate the devastating role of KAl(SO4)2·12H2O and the protective effects of gelatin on durability of treated papers, verified by the DP-related data. Additionally, it was found that the presence of alum is mainly responsible for the lightness decrease of the treated papers, and animal glue plays a primary role in paper yellowing. The findings in this research can deepen our understanding of the rate of paper degradation and color changes for the Xuan paper treated with the alum-glue solution.

Refining a tabular method for assessing the fire resistance of reinforced concrete structures

This paper reports the analysis of fire resistance assessment methods of building structures. Based on the results, it was established that conducting fire tests is not expedient and harmful to the environment. The use of estimation fire resistance assessment methods for reinforced concrete staircases is not considered possible due to the lack of appropriate tables with fire resistance classes for the tabular method. The use of the estimation zone method is also impossible because of the lack of temperature nomograms of temperature distribution during exposure to the standard fire temperature regime. There are also no described procedures for applying the estimation refined method for reinforced concrete staircases. So, using mathematical models, the existing type of reinforced concrete staircase was reproduced. Employing the finite-element method, the behavior of reinforced concrete stairwells under the influence of fire was investigated. Based on the results of these experiments, it was analyzed which structural geometric parameters of reinforced concrete stairwells have the greatest influence on their fire resistance. In this way, three independent, most significant geometric parameters of reinforced concrete stairwells were established – the height of the solid base, the thickness of the protective layer of the lower row of reinforcing bars, and the length of the span. Therefore, the ranges of the most significant structural geometric parameters of reinforced concrete stairwells were used to build a regression dependence of the fire resistance limit on these parameters in order to design a full factorial numerical experiment. After proving the adequacy of the results obtained according to the regression dependence, tables were constructed with the geometric parameters of reinforced concrete stairwells to determine the compliance of these structures with the required fire resistance class. The use of these tables will make it possible to reduce the risks of threats to human life and health during a fire by determining the possibility of using these structures with a guaranteed fire resistance class during design

CONSTRUCTION OF STATISTICAL MODELS OF CHEMICAL AND TECHNOLOGICAL OBJECTS ON THE BASIS OF A COMPLETE FACTOR EXPERIMENT

The article deals with the construction of a mathematical model of the process, which is created based on the results of a full factorial experiment. Often, only the results of experimental studies carried out at such objects are the information, based on the processing of which, according to the obtained mathematical model of the object, a high-quality control algorithm for this object can be implemented. At the same time, the construction of a mathematical model that describes the technological process with the required accuracy often involves a huge amount of work at the stage of experiments. The task of planning experiments is to establish the minimum required number of them and the conditions for their implementation, to choose methods for mathematical processing of the results, and to make decisions. Designing experiments significantly reduces the number of experiments required to obtain a process model. An active experiment involves a purposeful choice of factor values. Compared to a passive experiment, such an experiment turns out to be more efficient and economical, since the amount of experimental work is significantly reduced. In this article, in relation to chemical technology, the issues of organizing an experiment, mathematical processing of experimental data and mathematical planning of an experiment in the search for optimal conditions for conducting a technological process are described. Mathematical modeling and optimization of chemical technology objects is of great importance for obtaining higher professional education for students of the Educational and Scientific Institute of Chemical Technology and Engineering.

Nitrogen transfer from root exudates to the rhizobiome: A 15N stem feeding method

Plant roots exude nitrogen (N)-containing compounds, which are assimilated by the rhizobiome to maintain stoichiometric homeostasis. Various 15N-tracing methods exist to estimate the rhizobiome-N derived from root exudation but have never been validated with a full factorial experiment. We exposed ryegrass (Lolium multiflorum) to 15N solutions through different plant organs (stem or leaf feeding), with different 15N-tracers (urea or NH4NO3) and concentrations (64.5, 129 or 193 mmol 15N L−1). Stem feeding with either 15N-source at the highest concentration was the only effective way to quantify root exudate-N assimilation by the rhizobiome, and we recommend this 15N-labeling method for the reliable assessment of microbiome-N dynamics in the rhizosphere.

Foraging strategies of fungal mycelial networks: responses to quantity and distance of new resources.

Fungal mycelial networks are essential for translocating and storing water, nutrients, and carbon in forest ecosystems. In particular, wood decay fungi form mycelial networks that connect various woody debris on the forest floor. Understanding their foraging strategies is crucial for complehending the role of mycelium in carbon and nutrient cycling in forests. Previous studies have shown that mycelial networks initiate migration from the original woody resource (inoculum) to a new woody resource (bait) if the latter is sufficiently large but not if it is small. However, the impact of energetic costs during foraging, such as the distance to the bait, has not been considered. In the present study, we conducted full-factorial experiments with two factors, bait size (4 and 8cm3) and distance from the inoculum (1 and 15cm). An inoculum wood block, colonized by the wood decay fungus Phanerochaete velutina, was placed in one corner of a bioassay dish (24cm × 24cm) filled with unsterilized soil. Once the mycelium grew onto the soil to a distance >15cm from the inoculum, a sterilized new bait wood block (of either size) was placed on the soil at one of the two distances to be colonized by the mycelia from the inoculum. After 50days of incubation, the baits were harvested, and their dried weight was measured to calculate the absolute weight loss during incubation. The inoculum wood blocks were retrieved and placed on a new soil dish to determine whether the mycelium would grow out onto the soil again. If no growth occurred within 8days of additional incubation, we concluded that the mycelium had migrated from the inoculum to the bait. The results showed that mycelia in inocula coupled with baits positioned 1cm away migrated to the baits more frequently than those with baits positioned 15cm away. A structural equation model revealed that bait weight loss (energy gain) and hyphal coverage on the soil (foraging cost) significantly influenced mycelial migration decisions. These findings suggest that fungal mycelia may employ their own foraging strategies based on energetic benefits.

Impact of biorefinery processing conditions on the bioactive properties of fucoidan extracts from Saccharina latissima on SHK-1 cells

Fucoidans from brown macroalgae exhibit a wide array of bioactivities, from antioxidant to immunostimulatory effects. Their specific effects and efficacy depend on the molecular weight and structure of the polysaccharide chains, which in turn depends on the seaweed species and the methods used for fucoidan extraction and purification. In this study, a bench scale, three factor, three level full factorial experiment was used to determine the relationship between the extraction parameters (duration, hydrochloric acid concentration in extraction liquor, and temperature), the sulfation level and fucoidan yield. Three of the extractions representing the least severe and most severe extractions as well as a calculated sweet spot were scaled up to a pilot biorefinery (5 kg biomass per extraction). To evaluate the potential of using these complex polysaccharides as functional ingredients in salmon aquaculture, bioactivity of the three different fucoidan preparations was examined by in vitro assays with cultures of Atlantic salmon head kidney cells (SHK-1). All pilot extraction products induced an increase in SHK1 cell viability. In addition, “Too careful” also induced an upregulation of il1-β and sod1, both immune-related biomarkers. Interestingly, the expression of these biomarkers showed a positive correlation in SHK-1 cells stimulated with products from both “Too careful” and “Sweet spot” extractions. The data presented here show the extent of shift in bioactivity resulting from changes in the extraction severity in fucoidan biorefining and present the potential for fucoidan application as an immunostimulant for salmon cells.

Optimal Sand−Paving Parameters Determination of an Innovatively Developed Automatic Maize Seeding Machine

Maize is an important crop to ensure food safety. High-quality seeds can guarantee a good yield. The maize seed germination rate is the most important information for the maize industry, which can be obtained through the seed germination test. An essential stage in determining the germination rate is the planting of the seeds. The current seed planting process is fully manual, which is labor-intensive and costly, and it requires the development of an autonomous seeding machine. This research developed an automatic maize seeding machine, consisting of four operations: paving sand, seed layout, watering, and covering the seed. Among the four procedures, sand paving is a crucial step, the performance of which is affected by the gate opening size, conveyor speed, and sensor mounting location. Three performance evaluating factors are the weight of sand in the tray, the volume of sand left on the conveyor, and sand surface flatness. A full factorial experiment was designed with three variables and three levels to determine an appropriate factor combination. RGB-D information was used to calculate the volume of sand left on the conveyor and sand flatness. An analytic hierarchy process was employed to assign weights to the three evaluation indicators and score the various combinations of factors. The machine for paving sand achieved a satisfactory result with an opening size of 10.8 mm, a sensor distance of 9 cm, and a conveyor belt speed of 5.1 cm/s. With the most satisfactory factors determined, the machine shows superior performance to better meet practical applications.

Assessment of Processing Parameters of Pack Silicon Cementation onto P265GH Grade Steel.

The quantification of the single or combined variation of the process parameters specific to a thermochemical treatment is the key to a full factorial experiment and a first step in the development of computer-aided process engineering. Powdery solid media are frequently used in the practice of thermochemical treatments when the number of processed products is reduced, additional investments are not justified, or when there are no technological alternatives. The control of the process carried out in such powdery solid media involves both the control of the thermal and temporal parameters of the process on the layer growth kinetics and its phase composition, as well as the ratio of the powdery solid mixture mass percentage (active and neutral components, reaction activators, and components with the role of blocking the sintering tendency of the medium particles). In this paper, using the specific full factorial experiment (that is, a first-order complete factorial experiment (CFE)), the full model of the regression equation of the interactions between the specific process parameters of the silicide layer formation in a powdery solid media, applied to the low alloy P265GH steel grade and used in the petrochemical industry, were evaluated. Fe-ARMCO was chosen as the reference in the experimental research carried out.

Bumble bee pollination and the wildflower/crop trade-off: When do wildflower enhancements improve crop yield?

Populations of wild insect pollinators such as bumble bees are threatened worldwide, which compromises pollinator-dependent crop yields. Intentionally planting wildflower patches in agricultural landscapes can support these populations and increase the pollination of nearby crops via the “spillover effect” (i.e., the exporter hypothesis), but may also distract bees from the crops and reduce their pollination via the “Circe principle” (i.e., the aggregation hypothesis). Considering the potentially high costs of these management strategies and the necessity to support wild insect pollinators in the Anthropocene, there is a pressing need to provide simulation tools that can inform best practices for wildflower plantings in agro-ecosystems. We developed a spatially implicit ordinary differential equations (ODEs) model specifically designed to determine the optimal wildflower-to-crop ratio as a function of wildflower patch (i) attractiveness, (ii) nutritional benefits, and (iii) blooming period relative to the crop. The model represents the population dynamics of a bumble bee colony and floral resources (crop and wildflower) in the landscape and nest during one harvesting season. We conduct a full factorial simulation experiment to identify the optimal characteristics of the wildflower patch (i.e., blooming period, attractiveness, relative abundance) that maximise crop yield via the enhancement of the number of bees pollinating crop flowers in a fictional blueberry farm. Our results suggest that providing highly attractive and nutritive wildflower resources before and not during the crop blooming season is the most beneficial strategy. When both flower types are in competition, pollination services can decrease, either when wildflowers are too attractive, or if they provide less benefits to the bees than the crop due to a trade-off between resources quality versus quantity.

Investigation on Thermal Barrier Coating Damages for Ultrafast Laser Drilling of Cooling Holes.

To mitigate the challenges pertaining to coating damage and processing defects arising from the utilization of ultrafast laser drilling for microhole creation in thermal barrier coatings (TBCs), thereby exerting substantial influence on the long-term durability of these microholes, the investigation proposes a comprehensive methodology. It encompasses the design of a two-factor four-level full factorial experiment and the execution of experimental research on picosecond laser drilling of TBC microholes. By meticulously analyzing the morphology of the microholes and the coating interface, the damage mechanisms associated with picosecond laser drilling of TBC microholes, as well as the influence of laser process parameters on coating damage, are revealed. The findings reveal that the optimal microhole entrance quality and the lowest roughness along the hole perimeter are attained at a laser power of 12 W and a scanning speed of 320 mm/s. Moreover, at a laser power of 30 W and a scanning speed of 320 mm/s, the minimal crack length on the blunt angle side of the hole and the highest machining quality are observed.