Final Shell Research Articles

Chitosan-Coated Alginate Matrices with Protein-Based Biostimulants: A Controlled-Release System for Sustainable Agriculture

Developing biodegradable complex fertilizers is crucial for sustainable agriculture to reduce the environmental impact of mineral fertilizers and enhance soil quality. This study evaluated chitosan-based hydrogel coatings for sodium alginate matrices encapsulating amino acid hydrolysates from mealworm larvae, known for their plant growth-promoting properties. The research aims to identify the potential of biopolymer matrices for producing biodegradable slow-release fertilizers and to outline future development pathways necessary for this technology to be usable in the fertilizer industry. Chitosan coatings prepared with citric acid and crosslinked with ascorbic acid optimized plant growth, while those using acetic acid negatively affected it. Water absorption and nutrient release tests showed that chitosan coatings reduced water uptake and slowed initial nutrient release compared to uncoated samples. Leaching assays confirmed controlled-release behavior, with an initial burst followed by stability, driven by alginate–chitosan interactions and ion exchange. The X-ray diffraction (XRD) analysis revealed that adding hydrolysate and chitosan increased amorphousness and reduced porosity, improving structural properties. Thermogravimetric analysis (TGA) and Fourier-transform infrared (FTIR) spectroscopy demonstrated enhanced homogeneity and the presence of chemical interactions, which led to improvements in the material’s thermal stability and chemical characteristics. Biodegradation tests indicated greater durability of chitosan-coated composites, although hydrolysate incorporation accelerated decomposition due to its acidic pH. Germination tests confirmed no phytotoxicity and highlighted the potential of biopolymeric matrices for slow nutrient release. These findings indicate the possibilities of chitosan-coated alginate matrices as sustainable fertilizers, emphasizing the importance of adjusting coating composition and hydrolysate pH for enhanced efficacy and environmental benefits. The main recommendation for future research focuses on optimizing the chitosan coating process by exploring whether adding hydrolysate to the chitosan solution can reduce diffusional losses. Additionally, investigating the use of glycerol in the alginate matrix to minimize pore size and subsequent losses during coating is suggested. Future studies should prioritize analyzing percentage losses during the crosslinking of the alginate matrix, chitosan coating, and final shell crosslinking. This pioneering research highlights the potential for encapsulating liquid fertilizers in biopolymer matrices, offering promising applications in modern sustainable agriculture, which has not been studied in other publications.

Strategic planning of open pit mining operations using the Micromine Beyond Optimiser

Modern software products allow to determine the quantity and quality of ore at any point of the deposit and, accordingly, to identify the optimal pit shell using specialized algorithms. Such algorithms make it possible to create the final open pit shell even with a broken bottom for several neighboring ore bodies. Currently, optimization solutions in the mining industry require the determination of the maximum present value of profit or the minimum stated costs. It allows to make strategic planning decisions. Strategic planning of open-pit mining operations in the development of mineral deposits in Ukraine can be implemented using the Micromine Beyond Pit Optimizer. The authors considered the parameters that affect the boundaries of the pit field and the optimization criteria.

Growth performance and reproductive qualities of breeder snails (Archachatina marginata) fed different sources of protein

This experiment was conducted to compare the effects of different protein sources on the growth and reproductive performances of breeder snails, as protein sources are the main requirement for fast growth and development of cells for reproduction. Soya bean meal (SBM), cottonseed meal (CSM), and groundnut cake (GNC) were fed to the breeder snails. The snails were eight (8) months old with an initial average weight of 98.93g, and the experiment lasted for 12 weeks. Sixty (60) Archachatina marginata breeder snails were randomly selected and divided into 4 groups of fifteen (15) snails per treatment which were replicated three (3) times in each of the groups. The parameters examined were growth performance, feed intake, feed conversion ratio, and reproductive characteristics. Data collected were analyzed by the use of a one-way analysis of variance and significant means were separated with the Duncan Multiple Ranged Test at a 5% level of probability using SAS, 2011 [10]. The study revealed that soya bean meal (SBM) supports higher final body weight, body weight gain, and percentage fertility, while soya bean meal and cottonseed meal had higher percentage hatchability. However, no significant (P>0.05) differences were recorded in the final shell circumference, shell circumference gain, final shell length, and shell length gain. It was concluded that compounded feed with soya bean meal as the main protein source abetted fast growth and better productive performance.

Performance evaluation of grower snails fed varying levels of groundnut cake

This experiment was conducted to determine the effects of groundnut cake (GNC) fed to grower snails as the main protein source at varying levels, of inclusion 23%, 25%, and, 27%. This experiment was carried out at the Federal College of Education Teaching and Research Farm, Asaba, Delta state of Nigeria. The snails were four (4) months old each and the experiment lasted for 12 weeks, forty-eight (48) grower snails were randomly divided into three (3) groups of sixteen snails each per treatment, which were replicated four (4) times. The parameters considered were growth performance, feed intake, feed conversion ratio, carcass, and shell characteristics. Data collected were analyzed by use of one-way analysis of variance and significant means were separated using Duncan’s multiple ranged test at a 5% level of probability (SAS, 2011). The study showed that snails fed 27% of GNC supported higher body weight, live weight, and dressing percentage. However, no significant (P<0.05) differences were recorded in the final shell circumference, shell circumference gain, final shell length, and shell length gain. A formulated ration containing as much as 27% GNC will go a long way in ensuring the all-year availability of feed for commercial snail production.

Optimized formula for the hybrid abalone Haliotis discus hannai♀ × H. fulgens♂: Betaine supplementation increases the use of rice bran meal as a replacement for kelp

Optimized formula for the hybrid abalone Haliotis discus hannai♀ × H. fulgens♂: Betaine supplementation increases the use of rice bran meal as a replacement for kelp

Synthesis of Al@Al2O3 microcapsules by a triple-coating method for high-temperature thermal energy storage

Metallic aluminum (Al) has a high melting point and high thermal storage density, making it a proper candidate for high-temperature thermal storage applications including waste heat recovery and solar thermal utilization. To solve the problems of easy leakage after melting, high reactivity and high corrosiveness during application, microcapsules with a stable alumina shell were developed based on a triple coating method. The preparation process was divided into three steps: (1) generation of a boehmite layer on the surface of the Al powders via boiling water treatment, which was designed to slow down the corrosion of the precursor in the subsequent treatment; (2) production of Al(OH)3 gel layer on the surface of the particles through Sol-gel treatment and (3) formation of the final dense Al2O3 shell after thermal oxidation treatment. The synthesized [email protected]2O3 microcapsules had a melting point of 655.5 °C and a latent heat of 227 J/g. Notably, the latent heat of microcapsules remained almost constant after 100 melting-solidification cycle experiments, indicating a good cycling properties. In summary, the newly developed [email protected]2O3 microcapsules have a broad application prospect in the field of high-temperature thermal storage.

Spontaneous Patterning of Binary Ligand Mixtures on CdSe Nanocrystals: From Random to Janus Packing.

Binary compositions of surface ligands are known to improve the colloidal stability and fluorescence quantum yield of nanocrystals (NCs), due to ligand-ligand interactions and surface organization. Herein, we follow the thermodynamics of a ligand exchange reaction of CdSe NCs with alkylthiol mixtures. The effects of ligand polarity and length difference on ligand packing were investigated using isothermal titration calorimetry (ITC). The thermodynamic signature of the formation of mixed ligand shells was observed. Correlating the experimental results with thermodynamic mixing models has allowed us to calculate the interchain interactions and to infer the final ligand shell configuration. Our findings demonstrate that, in contrast to macroscopic surfaces, the small dimensions of the NCs and the subsequent increased interfacial region between dissimilar ligands allow the formation of a myriad of clustering patterns, controlled by the interligand interactions. This work provides a fundamental understanding of the parameters determining the ligand shell structure and should help guide smart surface design toward NC-based applications.

Effects of semidiurnal water column acidification and sediment presence on growth and survival of the bivalve Mya arenaria

Effects of semidiurnal water column acidification and sediment presence on growth and survival of the bivalve Mya arenaria

Prediction of stamping parameters for imitation π-shaped lithium battery shells by building variable weight and threshold pelican-BP neural networks

With the rapid development of artificial neural networks, more sophisticated network models and more accurate prediction results are provided for solving engineering applications. In this paper, the weights and thresholds of the feedforward neural network model were optimized using the pelican algorithm, and the optimal solution was output by simulating the pelican predation scheme and assigned as the new parameters of the neural network. A POA-BP network model was proposed, and its better prediction was demonstrated by comparing the fitting and prediction performance with 13 neural network models such as random forest, support vector machine, and wavelet basis by evaluating metrics such as RMSE, MSE, and MAE. To further improve the prediction accuracy, different hidden layer topologies of POA-BP were compared, and the Monte Carlo method was used to obtain seven design variables for the lithium battery shell size parameters, and parameter regression prediction was performed for the structure after the variable density topology optimization used the isotropic material interpolation model (SIMP) with the moving asymptote method by invoking the MinGW-w64 compiler, and the 1-3-1 neural network was selected model to predict each dimension of the battery shell structure, the final shell weight reduction ratio was 18.12% and the first-order intrinsic frequency was increased by 14.56%.

Design and optimization of free-form surfaces for modular concrete 3D printing

Although they are very efficient structures, concrete shells have lost popularity due to the complexity of the traditional construction process using cast-in-place concrete. A key concept to overcome the labor-intensive formwork in situ is the segmentation of the shells into prefabricated parts. In order to avoid individual formworks during prefabrication as well, the authors rely on extrusion-based 3D printing of strain-hardening cement-based composite (SHCC). The goal is a highly automated, scalable, and adaptable flow-prefabrication of modules controlled by a holistic digital design process. Such the creation of modular free-form shell structures can be accelerated significantly, resulting in structures comparable with gridshells. Starting with the problem statement and the elaboration of the technology used, the main contribution of this research is the development of geometrical methods for modularization based on given production conditions. The challenge lies in the free-form geometry discretization with respect to the structural analysis and within the defined constraints such as planar quads, no edge torsion, and minimal material consumption. Methods of discrete differential geometry for circular PQ (planar quad) mesh generation are combined with Response Surface Methodology (RSM) for multi-objective optimization of the global parameterized shape. The results were illustrated in a study case where the geometrical and structural production parameters of starting and final shell are compared.

Deformation and fracture behaviors of cylindrical battery shell during thermal runaway

Thermal runaway is one of the catastrophic failure modes of lithium-ion cells. During thermal runaway in cylindrical cells, sidewall shell rupture has been identified as a contributing factor for thermal runaway propagation in battery packs. Herein, the deformation and fracture behaviors of the battery shell during thermal runaway are investigated based on in-situ and ex-situ characterization as well as physics-based modeling. The deformation and fracture modes of the battery shell with/without Carbon Fiber Reinforced Polymer (CFRP) sleeves are identified. In the simulation, the strain introduced by thermal expansion of the system is considered, as well as the thermal and strain rate effects on the plastic stage. The final cell shell modeling is validated by cell thermal runaway tests. Results reveal the quantitative relation between shell deformation behaviors and the pressure and temperature distribution. Both the experiment and model demonstrate the effectiveness of adding a tight-fitting CFRP sleeve around the cell in limiting the side-wall rupture of the shell. The use of CFRP tubes introduces a novel phenomenon in the context of uneven temperature distribution. Results shed light on the mechanistic analysis of a cell side-wall rupture during thermal runaway and provide essential guidance for the next-generation safe battery design. • Fracture behaviors of cell shells during thermal runaway are investigated. • Experimental characterization validates the physics-based modeling. • The shell deformation depends on the inner pressure and temperature distribution. • The CFRP sleeve is an effective way to mitigate shell sidewall fractures.

Deep‐Red‐Emitting Colloidal Quantum Well Light‐Emitting Diodes Enabled through a Complex Design of Core/Crown/Double Shell Heterostructure

AbstractExtending the emission peak wavelength of quasi‐2D colloidal quantum wells has been an important quest to fully exploit the potential of these materials, which has not been possible due to the complications arising from the partial dissolution and recrystallization during growth to date. Here, the synthetic pathway of (CdSe/CdS)@(1‐4 CdS/CdZnS) (core/crown)@(colloidal atomic layer deposition shell/hot injection shell) hetero‐nanoplatelets (NPLs) using multiple techniques, which together enable highly efficient emission beyond 700 nm in the deep‐red region, is proposed and demonstrated. Given the challenges of using conventional hot injection procedure, a method that allows to obtain sufficiently thick and passivated NPLs as the seeds is developed. Consequently, through the final hot injection shell coating, thick NPLs with superior optical properties including a high photoluminescence quantum yield of 88% are achieved. These NPLs emitting at 701 nm exhibit a full‐width‐at‐half‐maximum of 26 nm, enabled by the successfully maintained quasi‐2D shape and minimum defects of the resulting heterostructure. The deep‐red light‐emitting diode (LED) device fabricated with these NPLs has shown to yield a high external quantum efficiency of 6.8% at 701 nm, which is on par with other types of LEDs in this spectral range.

Digital Form Finding Using Voronoi Pattern

Starting from funicular models, chain models and hanging membranes, the role of 3D physical models in optimized shape research is the basis of form-finding strategies. Advances in structural optimized shape design derive from the wide spread of special digital form-finding tools. The goal of this paper is to test and evaluate interdisciplinary approaches based on computational tools useful in the form finding of efficient structural systems. This work is aimed at designing an inverse hanging shape subdivided into polygonal voussoirs (Voronoi patterns) by relaxing a planar discrete and elastic system, loaded at each point and anchored along its boundary. The workflow involves shaping, discretization (from pre-shaped paneling to digital stereotomy) and structural analysis carried out using two modeling approaches, finite element and rigid block modeling, using an in-house software tool, LiABlock_3D (MATLAB®), to check the stress state and to evaluate the equilibrium stability of the final shell.

Total electrolyte balance for laying hens

ABSTRACT: This study was done to determine the best value of the total electrolyte balance (BET) concerning the variables of performance and egg quality of the laying hens. We investigated 240 Hy-Line Brown laying hens, of 30 to 46 weeks of age, adopting the completely randomized experimental design, which included five treatments (1000, 1250, 1500, 1750 and 2000 μeq / kg), 8 repetitions and 6 birds per unit. The performance and quality of the birds’ eggs were evaluated in the different treatments. The results were subjected to the analysis of variance and, wherever significant effect was noted, the regression equations were estimated, taking into account the electrolyte balance (μeq / kg) as a concomitant variable, applying the SAS statistical program (2001). The consumption, production, and feed conversion variables by dozen eggs, final bird weight, egg density, yolk color, Haugh Unit, albumen weight, shell weight, and egg weight, were found to be unaffected by the experimental BET values. The values of the feed conversion per egg mass, yolk weight and uniformity were affected by the different BETs. The electrolyte balance values showing minimum feed conversion, higher yolk weight, and better uniformity were, respectively, BET = 1400, 1330, and 1250 in μeq / kg of loads at the different temperatures. From the regression equations, the value indicated was BET=1390 for the 30- to 46-week-old laying hens. The electrolyte balance of the diet was found to affect the laying hens in terms of performance and egg quality.

Breeding and Larval Rearing of Asian Moon Scallop Amusium pleuronectes in Eastern Samar, Philippines

Asian moon scallop, Amusium pleuronectes, is among the most common commercially harvested scallop in the Philippines. This study investigated suitable conditioning methods, induced spawning, and documented scallop larval development at the Marine Fisheries Research and Development Center (MFRDC) Guiuan, Eastern Samar. Scallops held in tanks with flow-through water system without substrate yielded high survival rate of 48.06 ± 5.95%. Optimum water temperature was 28-29°C for maintaining scallops. Isochrysis galbana and Chaetoceros calcitrans were suitable microalgal feed for A. pleuronectes consumed at 7,388,888 cells min-1 per scallop. These significant results were applied in maintaining scallops at the hatchery. As a result, scallops with an average 19.8 mm shell length (SL) reached 37.5 mm SL within four months with a survival rate of 96.57 ± 2.04%, average daily growth rate (ADGR) of 0.13 ± 0.04 mm.day-1, and specific growth rate (SGR) of 3.92 ± 1.31%.d-1. Natural spawning was successful under controlled conditions while induced spawning trial through thermal stimulation, food shock, sexual stimulation, and serotonin injection resulted unsuccessful release of sperm and eggs. The estimated number of fertilized eggs per spawning ranged from 0.22-1.4 million. Fertilized eggs appeared spherical and dark in color with 54.2-62.57 µm in diameter. After nine hours, the larvae developed into trochophore stage with 59.08-84.4 µm in length. D-veliger with 120.37-157.07µm shell length developed after 24 hours. Development of the early umbone stage was reached on day 5; and on day 7, the umbo larvae become well-developed with shell length of 135.45-173.36 µm. On day 9, pedi-veligers were observed in the culture. Spat grew 312.41-509.48 µm on day 16 and survived until four months with final shell length of 4-10 mm. For the larval rearing, stocking density of A. pleuronectes larvae observed highest survival rate of 0.04 ± 0.03% at 200 larvae/L, while no larvae survived at 800 larvae/L due to contamination of protozoans in the culture medium.

Are bivalves susceptible to domestication selection? Using starvation tolerance to test for potential trait changes in eastern oyster larvae.

Conservation efforts are increasingly being challenged by a rapidly changing environment, and for some aquatic species the use of captive rearing or selective breeding is an attractive option. However, captivity itself can impose unintended artificial selection known as domestication selection (adaptation to culture conditions) and is relatively understudied for most marine species. To test for domestication selection in marine bivalves, we focused on a fitness-related trait (larval starvation resistance) that could be altered under artificial selection. Using larvae produced from a wild population of Crassostrea virginica and a selectively bred, disease-resistant line we measured growth and survival during starvation versus standard algal diet conditions. Larvae from both lineages showed a remarkable resilience to food limitation, possibly mediated by an ability to utilize dissolved organic matter for somatic maintenance. Water chemistry analysis showed dissolved organic carbon in filtered tank water to be at concentrations similar to natural river water. We observed that survival in larvae produced from the aquaculture line was significantly lower compared to larvae produced from wild broodstock (8 ± 3% and 21 ± 2%, respectively) near the end of a 10-day period with no food (phytoplankton). All larval cohorts had arrested growth and depressed respiration during the starvation period and took at least two days to recover once food was reintroduced before resuming growth. Respiration rate recovered rapidly and final shell length was similar between the two treatments Phenotypic differences between the wild and aquaculture lines suggest potential differences in the capacity to sustain extended food limitation, but this work requires replication with multiple selection lines and wild populations to make more general inferences about domestication selection. With this contribution we explore the potential for domestication selection in bivalves, discuss the physiological and fitness implications of reduced starvation tolerance, and aim to inspire further research on the topic.

Effects of dietary guar meal with or without beta-mannanase on performance and egg quality traits in laying hens

In this study, the effects of beta-mannanase supplementation to laying hens? diets with different guar meal GM ratios on performance and egg quality traits were investigated. The experimental period lasted 126 days. Ninety-six Lohman Brown hens at the age of 56 weeks were kept in individual cages. They were divided into 8 treatment groups as follows: 0% guar meal GM0 control ; 0% GM + 0.05% beta-mannanase GM0E ; 8% GM GM8 ; 8% GM + 0.05% beta-mannanase GM8E ; 16% GM GM16 ; 16% GM + 0.05% beta-mannanase GM16E ; 24% GM GM24 ; and 24% GM + 0.05% beta-mannanase GM24E . A photoperiod of 16.5 h light and 7.5 h dark was applied throughout the experiment. The present treatments had significant effects on changes in final live body weight, feed consumption, feed efficiency, egg production, egg weight, shell thickness, eggshell weight, shape index, yolk index, Haugh unit, and yolk pigmentation values P 0.05 . According to our results, guar meal might be used maximally at 16% in laying hen diets, because of its negative effects on laying performance and egg quality traits.

Stopped-Flow Dynamics Study on the Escape Behavior of Polyelectrolyte Macromolecules from Microgels: The Influence of the Path Length and Size.

We reported the fabrication of several monodispersed poly(2-vinyl pyridine)-poly(N-isopropylacrylamide) (P2VP-PNIPAM) microgels including the P2VP core (non-cross-linked) and PNIPAM (cross-linked) shell by mature emulsion polymerization. The fast escape behavior (diffusion process) of linear P2VP chains through a porous PNIPAM layer was investigated by a pH jump stopped-flow apparatus. The time-dependent dynamic traces (corresponding to the scattered light intensity) decreased at the initial timescale of several seconds and then reached an apparent equilibrium, confirming the efficient escape of P2VP chains from microgels. Compared with the previously reported literature, such an accelerated escape process resulted from the sharply increased internal charge repulsive force caused by the protonation of P2VP moieties under acidic conditions. The obtained characteristic relaxation times by single exponential fitting of these kinetic traces were dependent on the final pH values, equilibrium temperatures, shell thickness (path length), and cross-linking density (mesh size). We believe that this work can provide an efficient way to investigate hindered diffusion, especially the initial rapid diffusion stage. Not only that, the proposed model can also provide theoretical guidance to some practical applications, such as membrane separation and the exocytosis phenomenon of intracellular proteins or macromolecular substances.

Influence of the source arrangement on shell growth around GaN nanowires in molecular beam epitaxy

In a combined experimental and theoretical study, we investigate the influence of the material source arrangement in a molecular beam epitaxy (MBE) system on the growth of nanowire (NW) core-shell structures. In particular, we study the shell growth of GaN around GaN template NWs under the boundary condition that Ga and N do not impinge on a given sidewall facet at the same time. Our experiments with different V/III ratios and substrate temperatures show that obtaining shells with homogeneous thickness along the whole NW length is not straightforward. Analyzing in detail the shell morphology with and without substrate rotation, we find that the different azimuthal angles of the sources have a major impact on the Ga adatom kinetics and the final shell morphology. On the basis of these experimental results, we develop a diffusion model which takes into account different NW facets and the substrate. The model allows to describe well the experimental shell profiles and predicts that homogeneous shell growth can be achieved if the Ga and N source are arranged next to each other or for very high rotation speeds. Moreover, the modeling reveals that the growth on a given side facet can be categorized within one rotation in four different phases: the Ga wetting phase, the metal-rich growth phase, the N-rich growth phase, and the dissociation phase. The striking difference to growth processes on planar samples is that, in our case, diffusion takes place between different regions, i.e. the sidewall vs. the top facet and substrate, out of which on one N impinges not continuously, resulting in complex gradients in chemical potential that are modulated in time by substrate rotation. The comprehensiveness of our model provides a deep understanding of diffusion processes and the resulting adatom concentration, and could be applied to other 3D structures and material systems

Preparation of thermal infrared and microwave absorber using WO3/MnFe3O4/polyaniline nanocomposites

ABSTRACT In this study tungsten trioxide has been synthesised as a thermal infrared (TIR) absorbent by sol–gel method and characterised by X-ray diffraction (XRD), field emission scanning electron microscopes (FESEM) and transmission electron microscopy (TEM). XRD analysis shows that the single phase and hexagonal tungstate was prepared. The crystallite size measured by Scherer formula is in good accordance with the crystallite nano size measured by TEM. The polyaniline (PANI) was coated on WO3/MnFe2O3 nanoparticles (NPs, 50/50 wt%) via in situ polymerisation by core-shell structure WO3/MnFe2O3/PANI nanocomposite (50% wt as core). Structural and morphological characteristics of the produced nanocomposite were studied via X-ray diffraction, Fourier transformation infrared spectroscopy and scanning electron microscopy. The electric property was also performed by four probe method. The results showed that the WO3/MnFe2O3/PANI nanocomposites have good electric property. The TIR absorption of nanocomposite was investigated at 10–40 µm frequencies. The TIR images testing showed that the ability of infrared thermal imaging was increased by increasing WO3/MnFe2O3 as core and independent to increasing PANI as final shell. The test microwave absorption properties of the nanoparticles powder dispersing in PANI and thickness of 1.5 mm were investigated by using a vector network analysers in the frequency range of 8–12 GHz. A minimum reflection loss of the nanocomposite reaches -12 dB were observed at 8.8 and 11.6 GHz, respectively.