Natural Creatures Research Articles

Wettability Transition of the Picosecond Laser-Ablated 304 Stainless-Steel Surface via Low-Vacuum Heat Treatment.

Inspired by natural creatures, superhydrophobic surfaces with various adhesion behaviors have attracted significant scientific interest. In this study, by controlling the laser fluence, the scanning times, and the subsequent cleaning method, microcolumn arrays with different morphologies were fabricated on 304 stainless-steel surfaces using picosecond laser direct writing. To achieve wettability transition, the laser-processed samples were then subjected to heat treatments (120 °C) in air and in a low vacuum environment (6 kPa). The results show that after heat treatment in different environments and with various time lengths, the laser-processed surfaces become hydrophobic surfaces with different adhesion properties. It is worth noting that while surfaces heat-treated in air exhibit weak wettability transition potential and high adhesion, the surfaces heat-treated in a low vacuum environment present superhydrophobic and low adhesion properties with a minimum sliding angle of about 3.14°. Moreover, the low-vacuum heat-treated surfaces retain good superhydrophobic properties after 1 month of observation as well as an abrasion test. These transitions in hydrophobic behavior and adhesion properties may be mainly attributed to the heat treatment-induced (in the air or in a low vacuum environment) redistribution of surface compounds and the microstructure-induced alternation of the solid-liquid contact state. By controlling the laser processing parameters and the heat treatment time and environment, stable wettability transition and flexible adhesion control of stainless steel can be easily achieved.

Novel water soluble polymeric sensors for the sensitive and selective recognition of Fe3+/Fe2+ in aqueous media

Fe3+ and Fe2+ are common metal ions in natural water environments and creatures. The development of water-soluble fluorescent sensors for detecting Fe2+/Fe3+ ions was of great significance. In this work, two kinds of boron fluoride dipyrrole (BODIPY) fluorescent small-molecules were synthesized firstly. One of the small molecules contains a thioester bond that can be used as a chain transfer agent to participate in the polymerization process, and the other contains an unsaturated C = C double bond at the meso position. Through the reversible addition-fragmentation chain transfer polymerization (RAFT) polymerization method, methacrylic acid (MAA) and methacrylamide (MAM) were used as the main monomers, and small molecular fluorescent monomers were introduced to the end of the main chain. In this way, fluorescent macromolecules were obtained. The polymers were water soluble owing to the presence of long enough hydrophilic carboxyl and amide chains. These fluorescent probes exhibit high sensitivity to Fe2+/Fe3+, good selectivity, and anti-interference of other ions. The detection limit for Fe2+ was as low as 2.3 × 10−7 M, and the detection limit for Fe3+ can reach up to 4.5 × 10−7 M. The results show that these probes can be used as good sensors to identify Fe2+ and Fe3+. Moreover, the fluorophores could be incorporated into polymer chains as the RAFT reagents and/or functional monomers.

Nature Sunflower Stalk Pith with Zwitterionic Hydrogel Coating for Highly Efficient and Sustainable Solar Evaporation

AbstractSolar‐driven water evaporation is considered to be an appealing way to solve water scarcity issues globally. Various natural creatures possess unique structural features and exhibit an excellent pumping ability in arid environments. Motivated by sunflower stalk pith, here, the biomass porous foam modified with zwitterionic hydrogel coating for solar desalination devices is introduced. It is demonstrated that the multi‐curvature and gradient honeycomb architecture offers a remarkable solar desalination system, which combines critical aspects of solar evaporation including high light absorption, localizing converted heat, rapid water transport, water activation, and multi‐channel release of steam via its ubiquitous structure, and substantially outperforms other natural biomass materials. The device exhibits long‐term stability in actual seawater, as well as high performance for soybean oil emulsion and oily brines (crude oil, salts). Furthermore, the long‐term use of excellent storability to prevent putrefying is shown, which is attributed to the outstanding antifouling property of zwitterionic hydrogel. It is envisioned that the nature material with the advantage of being inexpensive, environmentally friendly, and portable, may be a new candidate for water purification and desalination.

Cross-Scale Biological Models of Species for Future Biomimetic Composite Design: A Review

The rise in structural performance requirements in engineering is driving the research and development of stronger, stiffer, and lighter materials. However, most traditional artificial materials are unable to meet the needs of modern industrial and technological development. In fact, multifarious creatures in nature are further ahead in their use of structural materials. There is a fairly limited selection of natural structural materials at ambient temperatures. They usually consist of hard and soft phases arranged in a complex hierarchy with characteristic dimensions ranging from nanoscale to macroscale. The resulting materials usually show a nearly perfect combination of strength and toughness integrated with lightweight characteristics. This is exactly what is required of engineering materials. In this review, different biological materials were divided into the following types in terms of structural elements: 1D fibrous structures, 2D layered structures, 3D cellular structures and heterogeneous interface structures. For each structural element, corresponding structure components and mechanical properties of typical organisms were well described. Abundant sophisticated models of natural biological structures were discussed contrastively. The purpose of this review was to summarize the excellent properties of multi-dimensional biological models with cross-scale features and to reveal the relationship between structure characteristics and function mechanism, which could provide valuable references for the design and optimization of a future biomimetic composite with high mechanical performance. This review is anticipated to not only inspire novel biomimetic design but also offer a window for the deep understanding of existing outstanding structural composites in diversified species, which could provide continuous innovative power for composite renovation in many engineering fields.

Bio-inspired shape-memory structural color hydrogel film

Structural colors, derived from existing natural creatures, have aroused widespread attention in the materials regulation for different applications. Here, inspired by the color adjusting mechanism of hummingbird, we present a novel shape-memory structural color hydrogel film by introducing shape memory polymers (SMPs) into synthetic inverse opal scaffold structure. The excellent flexibility as well as the inverse opal structure of the hydrogel films imparts them with stable stretchability and brilliant structural colors. Benefiting from the transient structural anisotropy of copolymers, the hybrid films are possessed with shape-morphing behaviors capability. Based on the shape transformations and color responsiveness performance, we have demonstrated diverse structural color actuators with complex shapes for different tasks. Notably, as the photothermal responsive graphene quantum dots were integrated into the hydrogel, the hybrid films could also be endowed with the feature of light-controlled reversible deformation with synchronous structural color variation. These features demonstrate that the presented shape-memory structural color hydrogel film is valuable for soft robotics with multi-functions of sensing, communication and disguise.

Integration of water collection and purification on cactus- and beetle-inspired eco-friendly superwettable materials

Freshwater shortage has been a terrible threat for the sustainable progress and development of human society in 21st century. Inspired from natural creatures, harvesting water from atmosphere has been a feasible and effective method to alleviate water shortage crisis. However, the recent works related to water collection just focuses on how to optimize fog-harvesting manners and efficiencies, the safety and availability of collected water are always ignored. In this paper, we proposed a new strategy accessed to freshwater resources through combining water collection and purification together on eco-friendly superwettable material inspired by cactus spines and desert beetles. Six superhydrophilic wedge-shaped patterns prepared by P25 TiO2 nanoparticles (NPs) were constructed on candle soot@polydimethylsiloxane (CS@PDMS) superhydrophobic coating. The special superhydrophilic regions not only effectively captured water from foggy environment but generated Laplace pressure gradient to faster drive water away. The bioinspired material exhibited an efficient water collection rate (WCR) of 14.9 ± 0.2 mg min−1 cm−2, which was 5.3 and 2.5 times larger than that on uniformed superhydrophilic and superhydrophobic surfaces, respectively. Because of the existence of photocatalytic P25 NPs in wetting areas, the harvested wastewater containing nine kinds of pesticides (0.5 mg/L) could be purified in low concentrations (< 5%) under UV light (365 nm, 5.0 ± 0.6 mW cm−2). Ten zebrafishes were still alive in such purified water for 72 h, as a contrast, the same number of fishes would almost die in untreated harvested wastewater in just 7 h. This work indeed opens up a new sight to freshwater accessibility, aiming to a promising project for alleviating water shortage around the world.

Where Are the Women?: An Ecofeminist Reading of William Golding’s &lt;em&gt;Lord of the Flies&lt;/em&gt;

The absence of female characters and their voices in William Golding’s Lord of the Flies (1954) has been previously examined. On the surface, this fiction focuses on the struggle and survival of a group of boys who are left alone on a Pacific island against the background of nuclear warfare. The only presence of women in the story seems to be the aunt via a boy’s narration. However, when approaching the fiction through the lens of ecofeminism, we can find a range of feminized entities which are metaphorically embodied in the natural surroundings of the secluded island. The boys’ interactions with these feminized creatures in nature showcase a master mentality prevalent in human-centered and male-dominated discourses, a problem many ecofeminists manage to redress. Investigating Golding’s Lord of the Flies from this angle, this paper discusses women’s subordination, men’s exploitation of nature, and the implications of reading Lord of the Flies from an ecofeminist perspective. I argue that an ecofeminist reading, which helps us complicate the interplay between men and women, women and nature, and the nature of patriarchal domination, contributes to our re-discovery of women’s voices underlying Lord of the Flies.

Finite element analysis of energy absorption characteristics for biomimetic thin-walled multi-cellular structure inspired by horsetails

Tubular thin-walled structure has attracted more and more attention because of its light weight and energy absorption characteristic, and has been widely applied to the fields of aerospace and automotive engineering. For millions of years, effective strategies in the biological tissues of nature creatures had evolved to synthesize structures that possess excellent mechanical properties. One impressive example is found in the internal morphology of horsetail plants. In this study, five kinds of the finite element model of multi-cellular thin-walled structures were established inspired by horsetails, and the energy absorption characteristics and crushing force efficiency of the above structures under axial impact loading were investigated by finite element method. Combined with the above bio-mimetic structures with good performance, a novel bio-mimetic multi-cellular thin-walled structure was proposed. The parameter study, including wall thickness, column diameter and impact angle were completed by numerical simulation method. The results show that the specific energy absorption and crushing force efficiency of the new proposed structure are 49.9 kJ/kg and 88.9% respectively, which are significantly higher than those of the conventional structure. The above bio-mimetic thin-walled structure inspired by horsetails can be applied in developing lightweight energy absorbing structure in the field of automotive or aircraft design.

Seeing Like the Sea: A Multispecies History of the Ceylon Pearl Fishery 1800–1925

Abstract The pearl fishery of Ceylon was a lucrative source of pearls as well as a theatre of colonial power. But instead of narrating a story of abstracted governmentality, this paper dives below the waves, braiding Tamil poetry with scientific material relating to the oyster and state sources concerning fishery administration. Taken together, these unearth a multi-species history of the human relationship to the seas. In the same way that pearl divers’ labour was a mode of knowing nature, so too, natural processes and marine creatures shaped, in turn, the economic, social and cultural worlds at the fishery. This nacreous, layered approach combines natural history, maritime labour and historical ecology to explore the fragile and interlocking balance below the waves which extended beyond humans to the molluscs, sharks, boring sponges and parasitic tapeworms of the Gulf of Mannar. The archive around the pearl fishery advances the animal and ecological histories of the Indian Ocean and also points towards ways of suturing the gulf between Indian and Sri Lankan scholarship.

Bioinspired Radiative Cooling Structure with Randomly Stacked Fibers for Efficient All-Day Passive Cooling.

Without the help of compression-based cooling systems, natural creatures have to make use of other things to decrease their body temperature to survive under thermally harsh conditions. This work finds that the silkworm cocoon of Bombyx mori protects pupae from the rapid temperature fluctuations via the randomly stacked silk fibers, which possess high solar reflectance and thermal emittance for thermal regulation. Inspired by this microstructure, the melt-blown polypropylene (MB-PP) with randomly stacked fibers is fabricated by a large-scale melt-blown fabrication method. For enhancing the thermal emittance of MB-PP, the surface-modified MB-PP (SMB-PP) is obtained by constructing the poly(dimethylsiloxane) film on the MB-PP. As the reason for its high solar reflectance (∼95%) and thermal emittance (∼0.82), the SMB-PP displays subambient temperature drops of 4 °C in the daytime and 5 °C in the nighttime, respectively. Moreover, building energy simulation indicates that the SMB-PP could save ∼132 GJ (∼58.1% of the baseline energy consumption) for 1 year in the contiguous United States. Overall, the bioinspired structures offer a novel pathway out of cooling buildings, showing great promising application prospects in zero-energy buildings.

Namib beetle optimization algorithm: A new meta‐heuristic method for feature selection and dimension reduction

SummaryToday, large amounts of data are generated in various applications such as smart cities and social networks, and their processing requires a lot of time. One of the methods of processing data types and reducing computational time on data is the use of dimension reduction methods. Reducing dimensions is a problem with the optimization approach and meta‐heuristic methods can be used to solve it. Namib beetles are an example of intelligent insects and creatures in nature that use an interesting strategy to survive and collect water in the desert. In this article, the behavior of Namib beetles has been used to collect water in the desert to model the Namib beetle optimization (NBO) algorithm. In the second phase of a binary version, this algorithm is used to select features and reduce dimensions. Experiments on CEC functions show that the proposed method has fewer errors than the DE, BBO, SHO, WOA, GOA, and HHO algorithms. In large dimensions such as 200, 500, and 1000 dimensions, the NBO algorithm of meta‐heuristic algorithms such as HHO and WOA has a better rank in the optimal calculation of benchmark functions. Experiments show that the proposed algorithm has a greater ability to reduce dimensions and feature selection than similar meta‐heuristic algorithms. In 87.5% of the experiments, the proposed method reduces the data space more than other compared methods.

Laser fabrication of modular superhydrophobic chips for reconfigurable assembly and self-propelled droplet manipulation

Natural creatures that enables controllable liquid transport provides the inspiration for developing novel microfluidic devices by engineering functional surfaces with superwettability. However, towards microfluidic applications, the strict requirements of sophisticated droplet manipulation make it challenging to reach this end. In this work, we report a conceptually new self-propelled droplet manipulation strategy based on reconfigurable superhydrophobic chips. The modular droplet chip (MDC) is developed by laser embossing a series of superhydrophobic structures on elastomer jigsaws that act as functional units. MDC is potable since only gravity is used as the driving force for dynamic manipulation of liquid droplets, including droplets transporting, splitting, merging and bouncing without mass loss. The MDC demonstrated reasonable anti-cross-contamination property due to the water repellence of the superhydrophobicity. Modular assembly of MDC enables different chip functions including solution dilution, SERS detection, cell labeling and chemical synthesis. As a miniature and portable experimental platform, the MDC is promising for next-generation lab-on-a-chip systems.

Hybrid-Light-Source Stereolithography for Fabricating Macro-Objects With Micro-Textures

Abstract Microscale surface structures are commonly found on macroscale bodies of natural creatures for their unique functions. However, it is difficult to fabricate such multi-scale geometry with conventional stereolithography processes that rely on either laser or digital micromirror device (DMD). More specifically, the DMD-based mask projection method displays the image of a cross section of the part on the resin to fabricate the entire layer efficiently; however, its display resolution is limited by the building area. In comparison, the laser-based vector scanning method builds smooth features using a focused laser beam with desired beam-width resolution; however, it has less throughput for its sequential nature. In this paper, we studied the hybrid-light-source stereolithography process that integrates both optical light sources to facilitate the fabrication of macro-objects with microscale surface structures (called micro-textures in the paper). The hardware system uses a novel calibration approach that ensures pixel-level dimensional accuracy across the two light sources. The software system enables designing the distribution and density of specific microscale textures on a macro-object by generating projection images and laser toolpaths for the two integrated light sources. Several test cases were fabricated to demonstrate the capability of the developed process. A large fabrication area (76.8–80.0 mm) with 50 μm micro-features can be achieved with a high throughput.

Focus on Bioinspired Textured Surfaces toward Fluid Drag Reduction: Recent Progresses and Challenges

After a long period of biological evolution, natural creatures will inevitably evolve body surfaces suitable for the living environment. The functions of natural biological surfaces are abundant and powerful, including antiadhesion, self‐cleaning, drag reduction, anti‐icing, wear resistance, and other characteristics. In the context of coping with the energy crisis, inspired by natural biological surface microstructures, researchers explore biomimetic surface microstructures that reduce fluid drag and investigate the mechanisms of drag reduction. Herein, mainly the current state of research on biomimetic textured surfaces that can be applied to fluid drag reduction is reviewed and the microstructures’ morphology, drag reduction mechanisms, and the fabrication techniques of textured surfaces are discussed in detail. In particular, the experimental methods for measuring the drag reduction effect of textured surfaces are introduced, which is extremely rare. The article concludes with a summary of existing problems and future directions in the research of biomimetic surface drag reduction technology. This Review can provide a reference for practical application and laboratory research of drag reduction in marine transportation, military weapons, aviation, and pipeline systems.

2020 Timoshenko Medal Acceptance Lecture: Mechanics: Evergreen and Forever New

2020 Timoshenko Medal Acceptance Lecture: Mechanics: Evergreen and Forever New

Toward the Burgeoning Optical Sensors with Ultra‐Precision Hierarchical Structures Inspired by Butterflies

AbstractIn recent years, there has been an increasing interest in the novel bioinspired sensors, especially for their selectivity, response time, and sensitivity. Particular attention is paid to the novel optical functional materials that are crucial for the sensors to achieve various energy transduction. Ideally, many critical parameters of the optical sensing materials can be appropriately tailored to meet various specific requirements using optimal design. Over a long and cruel evolution, nature's creatures have created a variety of photonic structures. One impressive example is the iridescent wings of butterfly. The natural photonic crystals on its surfaces have inspired diverse novel designs of optical functional sensing materials, especially in the past three years. Herein, this review mainly discusses recent advances of the burgeoning butterfly‐inspired sensing materials with optical properties that can be modulated in response to different external stimuli. First, their optical sensing performance to infrared radiation/thermal, vapor, liquid, pH, and so on are discussed in details. Then, the fabrication methods and their working mechanisms are also introduced. Furthermore, the general strategies of these emerging sensing materials and their potential applications are also discussed in‐depth as well as their limitations and the future challenges.

Learning from nature for healthcare, energy, and environment

Learning from nature for healthcare, energy, and environment

Bionic and its role in the development of pavilion design by using digital fabrication

In many aspects and areas, nature outperforms human capabilities, If we look at natural creatures as geometric design, they will outperform industrial ones ,Architecture and interior designs respond to the needs of communities and individuals, Through the studding of the elements, properties and qualities of nature, we can apply them to architecture. And Through (bionic) a science creation Industrial systems with some characteristics of living systems Bionics is an interdisciplinary field of science, the aim of which is to create models that map processes and principles of functioning of the living organisms that can be transferred to technology, The word bionic is a combination of the words biology and technology,Sarikaya divides this science into two parts: 1. Biomimetics: Through understanding biological systems and using these concepts using technology in design 2. Bioduplication :more advanced phase where new methods such as genetic engineering are being used to produce new materials and designs. The research problem can be identified The scientific need to study bio-engineering and connect it to digital technology to apply ecological and biological formations to architecture and interior design to create innovative design of pavilions. The research aims uncover the importance of using bio-engineering in architecture and design to identify digital indicators of mechanisms and processes and reach to the final form of design using digital manufacturing By using the scientific, analytical and descriptive approach ,Depend on digital technologies for element analysis and Design solutions for pavilions which can be developed by using computer techniques to create a simulated approach to units and its mechanism for working with each other and facilitating the simulation process also use digital manufacturing tools to make Implementation of designs.

A biomimetic skin-like sensor with multiple sensory capabilities based on hybrid ionogel

In the past decades, biomimetic skin-like materials have received increasing research interests for many applications in flexible devices, soft robotics and artificial intelligence. However, such highly sophisticated intelligence has been mainly found in natural creatures while rarely realized in artificial materials, owing to the challenge in integration of multifaceted mechanical performances and multiple sensory capabilities. Herein, a novel hybrid ionogel is developed by combining a dynamically entangled network with a covalently crosslinked network in an ionic liquid. The dynamically entangled network provides the hybrid ionogel with a wide spectrum of mechanical properties including high stretchability, recoverability, self-healing and 3D printability. The functional groups (hydroxyl and carbonyl) from polymer chains endow the hybrid ionogel with long-term and repeatable adhesiveness. More importantly, the assembled hybrid ionogel-based sensory systems demonstrate multiple sensory capabilities toward strain, temperature, and even recognition of various materials. This work not only provides insights for the fabrication of novel multifunctional ionogel, but also promotes the development of flexible devices with sophisticated intelligence.

African vultures optimization algorithm: A new nature-inspired metaheuristic algorithm for global optimization problems

Metaheuristics play a crucial role in solving optimization problems. The majority of such algorithms are inspired by collective intelligence and foraging of creatures in nature. In this paper, a new metaheuristic is proposed inspired by African vultures' lifestyle. The algorithm is named African Vultures Optimization Algorithm (AVOA) and simulates African vultures' foraging and navigation behaviors. To evaluate the performance of AVOA, it is first tested on 36 standard benchmark functions. A comparative study is then conducted that demonstrates the superiority of the proposed algorithm compared to several existing algorithms. To showcase the applicability of AVOA and its black box nature, it is employed to find optimal solutions for eleven engineering design problems. As per the experimental results, AVOA is the best algorithm on 30 out of 36 benchmark functions and provides superior performance on the majority of engineering case studies. Wilcoxon rank-sum test is used for statistical evaluation and indicates the significant superiority of the AVOA algorithm at a 95% confidence interval.