Characteristics of soil water repellency after sand dune stabilization in the Tengger Desert

Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study, the Capillary Rise Method was used to measure the SWR in the artificial vegetation area in Shapotou, located in the southeast area of the Tengger Desert, Ningxia Prov- ince of western China. The variation of the soil water repellency among different minor topographies, different depths and differ- ent particle sizes was analyzed. The results of the study indicate that the SWR shows distinct changes with vegetation restoration, and it increases with an increase in the period of dune stabilization. In the same vegetation area, the SWR of soils in inter-dune depressions or windward slopes is slightly greater than that in crest or leeward slopes. The SWR of 0-3 cm topsoil is significantly greater than that in the 3-6 cm soil layer. The SWR decreases with an increase in grain size and the differences among the SWRs of different sieved soil fractions are found to be significant. There is also a significantly positive correlation between the SWR and the proportion of soils with grain sizes of 0-0.05, 0.05-0.01 and 0.01-0.15 mm, and a significantly negative correlation between the SWR and the propotion of soils with grain sizes exceeding 0.15 mm. The increase of SWR in revegetation areas may depend on the continuous depositing of atmospheric dust on the stabilized dune surface as well as the formation of biological soil crusts, especially on the formation of algal and lichen crusts. Enhanced SWR influences the effectiveness of water use of sand plants in- habiting the sand dunes.

Comparative repellency effect of three plant extracts on Paederus beetles(Coleoptera: Staphylinidae), the cause of linear dermatitis in Iran

Objective: To investigate the repellent effect of neem, juniper and eucalyptus extracts as a form of protection against Paederus beetles, which are a cause of linear dermatitis in Iran.Methods: After collecting and extracting plant samples, the extracts were tested on Paederus beetles in three concentrations(2.5%, 5.0% and 10.0%) with direct method under laboratory conditions. The data were analyzed using SPSS software(version 20).Results: The results indicated that there was a significant difference between neem with juniper and eucalyptus at the 2.5% and 5.0% concentrations(P < 0.05), whereas there was a significant difference between all three extracts at the 10.0% concentration(P < 0.05).Conclusions: This is the first report on the repellent effect of these three plant extracts on Paederus beetles. Neem oil appeared to have the largest effect on Paederus spp. and juniper essential oil exhibited the second highest repellency, followed by eucalyptus.

Water Repellency of Cellulosic Fibrous Mats Impregnated with Organic Solutions Based on Recycled Polystyrene

Recycled polystyrene in combination with paraffin wax,alkyd resin,and gum rosin were used as components in formulations to investigate their water repellency when applied to cellulosic filter paper substrates.Polystyrene was used in concentration of 5,10,15 and 20%,alkyd resin and gum rosin of 5%each and paraffin wax of 0.5%.Totally,twenty four water repellent solutions were prepared.Water repellency was evaluated in terms of water absorption of the cellulosic fibrous mats.The relations between retention of solid substances of the formulations and grammage and water absorption of filter paper samples were also determined.The results showed that all the water repellent formulations exhibited a degree of water repellency.Water absorption decreased by increasing the polystyrene concentration in the solution and polystyrene retention by the impregnated filter paper samples.The incorporation of 0.5%paraffin wax improved the hydrophobicity of treated samples.The best of the three water repellent formulations including paraffin wax was found to be the“polystyrene+gum rosin+paraffin wax”solution followed by the“polystyrene+alkyd resin+paraffin wax”and“polystyrene+paraffin wax”solution.The inclusion of 5%gum rosin in polystyrene solutions compared to that of 0.5%paraffin wax was found more effective in almost all cases.

Evaluation of the Repellency Effect of Neem (<i>Melia azedarach</i>) Plant Extracts Based on the Mittler &Dadd Method

Using insect repellent compounds, especially during the warm months, provides comfort for people and preventsspreading of the insect-borne diseases such as dengue fever, malaria and Leishmaniasis. Poisons derived from plants contain alkaloids, glucoside and some essential oils that are taken from plant tissues. They may have repellent and insecticide properties with little toxicity to humans and animals. In this study, Neem plant1 from Bandar Abbas city was used to assess its repellency effect. Therefore, after drying and powdering using maceration method, final Neem extract concentration of 5%, 10% and 20% was provided. Mittler & Dadd methodology was hired to assess this effect. In this method, the antifeedant effect of the?Neem plant extract was evaluated on cabbage-feeding aphid (Brevicoryne brassicae). After 24 and 48 hours, the reduced numbers of feces spot of aphids showed that the ingestion of the provided food mixture contained Neem plant extract was significantly decreased. Here it was shown that the Neem plant extract could be used as an efficient repellent.

AsOBP1 is required for bioallethrin repellency in the malaria vector mosquito Anopheles sinensis

The use of insecticides,primarily pyrethroids,is a pivotal strategy for mosquito control globally.Bioallethrin,the first commercially available volatile pyrethroid,can elicit spatial(i.e.,noncontact)repellency to mosquitoes through the coactivation of ol-factory receptor neurons and sodium channels.However,the olfactory mechanism of the repellency elicited by bioallethrin in mosquitoes is still unclear.Here,we demonstrated the involvement of AsOBP1 in the bioallethrin repellency in Anopheles sinensis,one of the main vectors of vivax malaria in China and other Southeast Asian countries.The behavioral and electrophysiological analyses in AsOrco-/-mutant found that the spa-tial repellency elicited by bioallethrin depended on the odorant receptor(OR)-mediated olfactory pathway.Furthermore,the repellency was reduced in the AsOBPI^(-/-)mutant and a pyrethroid-resistant strain,in which the expression of AsOBPI was significantly decreased.Moreover,recombinant AsOBP1 protein bound to bioallethrin in an in vitro competition assay.These results indicate that activation of the AsOBP1-mediated olfac-tory pathway is an important component of bioallethrin repellency.Our research lays the foundation for further elucidation into the olfactory mechanism of bioallethrin repellency and the behavioral modifications of pyrethroid-resistant mosquitoes.

Rational Fabrication of Superhydrophobic Nanocone Surface for Dynamic Water Repellency and Anti-icing Potential

In this work,a simple and economic route was presented to fabricate an anti-icing superhydrophobic surface with nanocone structures,which were constructed only by one-step facile method of hydrothermal treatment with zinc acetate on the aluminum substrate.After modifying with fluoroalkylsilane (FAS-17),the nanocone structures with the appropriate size could induce the high superhydrophobicity with the water contact angle reaching 160.2° ± 0.4° and the sliding angle only being 1 ° ± 0.5°.Under the dynamic environments,the impact droplets could rapidly bounced off the surface with the shorter contact time of^1 0.6 ms,and it was mainly attributing to lower capillary adhesive force (water adhesion force of 4.1 μN) induced by the open system of nanocone structures.Furthermore,the superhydrophobic nanocone surfaces were verified to be a promising anti-icing/icephobic materials,on which the water droplets needed to spend the time of ~517 s to complete the entire freezing process at-10 ℃,displaying the increased ~50 times of icing-delay performance comparing with untreated substrate.Even if ice finally was formed on the superhydrophobic nanocone surfaces,it could be easily removed away with lower ice adhesion of^45 kPa.The repeatable measurement of ice adhesion strength on the same place of the superhydrophobic surface is still far less than the surface ice adhesion of smooth substrate,exhibiting better stability.

Water Repellency in Calcareous Soils Under Different Land Uses in Western Iran

Soil wettability and water repellency, two important soil physical properties, play an important role in water retention and water conductivity in arid and semi-arid regions. To date, there is a lack of information on soil water repellency in calcareous soils of western lran. In this study, soil water repellency and its affecting factors were studied using 20 soil series collected from Hamadan Province~ western Iran. The effects of soil properties including organic carbon content （SOC）, total nitrogen （TN）, C：N ratio, texture, CaCO3 content, and both fungal and bacterial activities on water repellency were investigated using air-dried, oven-dried and heated soil samples. Water repellency index （WRI） was determined using the short-time sorptivity （water/ethanol） method. To distinguish the actual effects of SOC, a set of soil samples were heated at 300 ~C to remove SOC and then WRI was measured on the heated samples. Relative water repellency index （RWRI） was defined as the change of WRI due to heating relative to the oven-dry WRI value. Results of the WRI values showed that the soils were sub-critically water-repellent. Pasture soils had higher WRI values compared to tilled soils, resulting from high SOC and TN, and high activities of bacteria and fungi. It was observed that SOC, TN, fungal activity, and SOC：clay ratio had significant positive impacts on WRI. Strong positive correlations of RWRI with SOC, TN and fungal activity were also observed. Pedotransfer functions derived for predicting WRI showed that the WRI values had an increasing trend with the increases in fungal activity, salinity, alkalinity and fine clay content, but showed a decreasing trend with increasing bacterial activity.

Comprehensive Overview and Analytical Study on Automatic Bird Repellent Laser System for Crop Protection

Birds are a huge hazard to agriculture all around the world,causing harm to profitable field crops.Growers use a variety of techniques to keep them away,including visual,auditory,tactile,and olfactory deterrents. This study presents a comprehensive overview of current bird repellant approaches used in agricultural contexts,as well as potential new ways. The bird repellent techniques include Internet of Things technology,Deep Learning,Convolutional Neural Network,Unmanned Aerial Vehicles,Wireless Sensor Networks and Laser biotechnology. This study’s goal is to find and review about previous approach towards repellent of birds in the crop fields using various technologies.

Evaluation of the toxicity and repellency of tropical plant extract against subterranean termites,Globitermes sulphureus and Coptotermes gestroi

The harmful effects of chemical-based termiticides and the increased incidence of termite resistance have resulted in the need for safer and more effective termiticides.Therefore,the screening of antitermiticidal activity of naturally-occurring products could possibly hamper an alternative means in termite control strategies.The aims of this study were to determine the toxicity and repellency of L.leucocephala,A.paniculata,Az.indica and P.niruri crude extracts against two subterranean termites,G.sulphureus and C.gestroi.Bioassays were conducted by applying varying concentrations of the plant extracts(10,000 ppm,5000 ppm and 500 ppm)on both termite species under laboratory conditions.All extracts exhibited a significant antitermiticidal activity in time-and concentration-dependent manners after 14 days of exposure.The highest mortality of G.sulpureus and C.gestroi were noted in all methanolic extracts of P.niruri,L.leucocephala,A.paniculata,Az.indica at 10,000 ppm.High repellent activity was also noted in the choice bioassay when both termites were treated with all methanolic extracts at 10,000 ppm.

Flexible Biofoams Based on Furanics and Fatty Acids Esterified Tannin

Water repellant,flexible biofoams using tannin esterified with various fatty acid chains,namely lauric,palmitic and oleic acids,by reaction with lauryl chloride,palmitoyl chloride,and oleyl chloride were developed and their characteristics compared with the equivalently esterified rigid biofoams.Glycerol,while initially added to control the reaction temperature,was used as a plasticizer yielding flexible biofoams presenting the same water repellant character that the equivalent rigid foams.Acetaldehyde was used as the cross-linking agent instead of formaldehyde,as it showed a better performance with the esterified tannin.The compression results showed a significant decrease of the Modulus of Elasticity(MOE)of the flexible foams in relation to that of the rigid foams,confirming their flexible character.The lauryl-and palmitoyl-esterified biofoams presented similar mechanical properties,while the oleyl-esterified biofoam presented different mechanical and morphological result not really showing the expected flexibility.Both the esterified rigid and flexible tannin-based biofoams showed good water resistance and their sessile drop contact angle analysis as a function of time confirmed this characteristic.Scanning Electron Microscope(SEM)analysis showed the flexible foams to present a higher proportion of closed cells than the rigid foams.Conversely,the cells depth of the flexible foams was lower than that of the rigid foam.As regards their thermal resistance,the flexible foams showed a slight loss of mass compared to the rigid ones without glycerol.Both types of foams presented much lower surface friability of non-esterified rigid foams.

Energy Efficient and Intelligent Mosquito Repellent Fuzzy Control System

Mosquitoes are of great concern for occasionally carrying noxious diseases(dengue,malaria,zika,and yellow fever).To control mosquitoes,it is very crucial to effectively monitor their behavioral trends and presence.Traditional mosquito repellent works by heating small pads soaked in repellant,which then diffuses a protected area around you,a great alternative to spraying yourself with insecticide.But they have limitations,including the range,turning them on manually,and then waiting for the protection to kick in when the mosquitoes may find you.This research aims to design a fuzzy-based controller to solve the above issues by automatically determining a mosquito repellent’s speed and active time.The speed and active time depend on the repellent cartridge and the number of mosquitoes.The Mamdani model is used in the proposed fuzzy system(FS).The FS consists of identifying unambiguous inputs,a fuzzification process,rule evaluation,and a defuzzification process to produce unambiguous outputs.The input variables used are the repellent cartridge and the number of mosquitoes,and the speed of mosquito repellent is used as the output variable.The whole FS is designed and simulated using MATLAB Simulink R2016b.The proposed FS is executed and verified utilizing a microcontroller using its pulse width modulation capability.Different simulations of the proposed model are performed in many nonlinear processes.Then,a comparative analysis of the outcomes under similar conditions confirms the higher accuracy of the FS,yielding a maximum relative error of 10%.The experimental outcomes show that the root mean square error is reduced by 67.68%,and the mean absolute percentage error is reduced by 52.46%.Using a fuzzy-based mosquito repellent can help maintain the speed of mosquito repellent and control the energy used by the mosquito repellent.

Self-Cross-Linked Tannin-Aminated Tannin Surface Coatings for Particleboard

Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin’s hydroxyl groups with the–NH_(2)groups on the aminated tannin to form–NH-bridges between the two.The resulting particleboard coating gave encouraging results when pressed at 180℃for 3 min.Conversely,the system in which tannin was reacted/cross-liked with urea(ATU)by a similar amination reaction did not perform as well as the ATT system,and this even when a higher curing temperature and longer hot press time were used.In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity.Nonetheless,substituting the tannin–OHs with the urea–NH_(2)groups appeared to also take place.ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test.The ATT system was shown to be between 95%and 98%biosourced.The difference appeared to be due,by TMA analysis,to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating.The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS^(13)C NMR.

Morphological basis for the waterproof characteristic of bird plumage

A surface variable, density of water-feather touching points （Dp） was proposed in this paper to express surface property of water repellency of contour feather. Tests in 29 species using breast contour feathers indicated that Dp was small in tericolous species, medium in wading and diving species, large in swimming species, with only a few exceptions. This implied that birds achieve appropriate Dp by optimizing the microstructure of feather to meet the requirement of water repellency. Therefore, Dp was a morphological marker linking structure and function of feather in studies of adaptive evolution of birds.

Heterogeneity of Physico-Chemical Properties in Structured Soils and Its Consequences

Structured soils are characterized by the presence of inter- and intra-aggregate pore systems and aggregates, which show varying chemical, physical, and biological properties depending on the aggregate type and land use system. How far these aspects also affect the ion exchange processes and to what extent the interaction between the carbon distribution and kind of organic substances affect the internal soil strength as well as hydraulic properties like wettability are still under discussion. Thus, the objective of this research was to clarify the effect of soil aggregation on physical and chemical properties of structured soils at two scales: homogenized material and single aggregates. Data obtained by sequentially peeling off soil aggregates layers revealed gradients in the chemical composition from the aggregate surface to the aggregate core. In aggregates from long term untreated forest soils we found lower amounts of carbon in the external layer, while in arable soils the differentiation was not pronounced. However, soil aggregates originating from these sites exhibited a higher concentration of microbial activity in the outer aggregate layer and declined towards the interior. Furthermore, soil depth and the vegetation type affected the wettability. Aggregate strength depended on water suction and differences in tillage treatments.

Fumigant and repellent properties of sesquiterpene-rich essential oil from Teucrium polium subsp,capitatum(L.)

Objective:To test fumigant and repellent properties of sesquiterpene—rich essential oil from Teucrium polium subsp.capitation(L.).Methods:The fumigant toxicity test was performed at(27±1)℃.(65± 5)%relative humidity,and under darkness condition and 24 h exposure time.The chemical composition of the isolated oils was examined by gas chromatography—mass spectrometry.Results:The major compounds were α-cadiuol(46.2%),earyophyllene oxide(25.9%),α muurolol epi(8.1%),cadalene(3.7%) and longiverbenone(2.9%).In all cases,considerable differences in mortality of insect to essential oil vapor were observed in different concentrations and exposure times.Callosobruchus maculatus(C.maculates)(LC_(50)=148.9μL/L air) was more susceptible to the tested plant product than Teucrium castaneum(T.castaneum)(LC_(50)=360.2μL/L ain based on LC_(50)values.In the present investigation,the concentration of 3μ L /mL acetone showed 60% and 52% repellency against T.casteneum and C.maculatus adults,respectively.Conclusions:The results suggests that sesquiterpene—rich essential oils from the tested plant could be used as a potential control agent for stored—product insects.

Interfacial phenomena of water striders on water surfaces: a review from biology to biomechanics

Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical research into water striders. Morphological and behavioral traits of water striders are summarized and discussed from biomechanical perspectives, along with comparative study. This integrated review also highlights potential directions for studies on water-walking arthropods,which might inspire future biological and biomechanical research.

Repellent properties of Cardiospermum,halicacabum Linn.(Family:Sapindaceae)plant leaf extracts against three important vector mosquitoes

Objective:To determine repellent activity of hexane,ethyl acetate,benzene,chloroform and methanol extract of Cardiospermum halicacabum,(C.halicacabum) against Culex quinque/ascialus(Cx.quinquefuscialus),Aedes aegypti(Ae.aegypli) and Anopheles slephensi(An.slephensi). Methods:Evaluation was carried out in a net cage(45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005;The plant leaf crude extracts of C.halicacabum was applied at 1.0,2.5,and 5.0 me/cm^2 separately in the exposed area of the fore arm.Only ethanol served as control.Results:In this observation,the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person,and also,the repellent activity was dependent on the strength of the plant extracts.The tested plant crude extracts had exerted promising repellent against all the three mosquitoes.Conclusions:From the results it can be concluded the crude extract of C.halicacabum was potential for controlling Cx.quinquefasciatus, Ae.aegypli and An.slephensi mosquitoes.

Physical properties of soil in Pine elliottii and Eucalyptus cloeziana plantations in the Vhembe biosphere,Limpopo Province of South Africa

Plantation establishment using invasive alien plants is common in South Africa,but the effects of these plants on soil physical properties in the Vhembe biosphere is unknown.In this comparative study,soils underneath Pinus elliottii and Eucalyptus cloeziana were assessed for differences in physical properties compared to soils underneath adjacent natural sites in the Entabeni plantation in the Vhembe biosphere in Limpopo Province,South Africa.Soils were collected from topsoil over 3 months and quantified for gravimetric soil moisture,penetration resistance,soil infiltration,hydraulic conductivity and soil water repellency.For all 3 months,soils from both P.elliottii and E.cloeziana plantations were compact and had low penetration resistance compared to soils from adjacent natural sites.Soil infiltration and hydraulic conductivity were significantly(p\0.05)lower in soils from plantations compared to soils from adjacent natural sites,and more so from the E.cloeziana plantation than from P.elliottii.Soil water repellency was observed in soils from E.cloeziana only in May and June.Soils from the invasive alien tree plantation have decreased soil moisture,infiltration rate,hydraulic conductivity and are compact as well as repellent(only E.cloeziana),all poor soil physical properties.However,this decline in soil physical properties was not uniform between the two invasive alien plantation species;hence we cannot generalize about the effects of invasive alien plantation species on soil physical properties,and further research is required across different ecological regions.

Urethane Modified Hydrophobic Compact Wood Pulp Paper for Oil Spill Cleanup: A Preliminary Study

Oil spills and oil/water wastewater are among the great concerns regarding oil pollution.Existing technologies face many limitations and in some cases are responsible for causing secondary pollution,therefore there is as seek for environmental friendly solutions.Biomass,from which celluloses are highlighted,are being employed for oil/water separation or oil absorbents membranes.Usually,these membranes are obtained by freeze drying of CNF(cellulose nano-fibrils)suspensions followed by chemical modification for hydrophobization,which involves expensive process as chemical vapor deposition and expensive reactants as sylanes,turning these processes hardly scalable.Here,we produced a natural porous structure paper from eucalyptus pulp fibers modified by a dipping and heating process in a blocked diisocyanate solution.After the surface treatment,contact angle with water reached 144°and water absorption reduced seven times,keeping the good oil absorbance.The chemical modification process is simple to be performed and use a very low quantity of reactant estimated to be less than 0.1 wt%based on cellulose.The good mechanical properties of the material allows its use in non usual conditions which can be of great importance depending on the environmental conditions.

Plasma-induced graft polymerization on the surface of aramid fabrics with improved omniphobicity and washing durability

Durable superomniphobic surfaces are desirable for their practical applications,including selfcleaning,non-fouling,protective clothing and the separation of liquids.The plasma-induced polymerization of environmentally friendly C6 from a perfluoralkyl methlacrylate copolymer emulsion,AG-E081,was performed and a durable omniphobic fabric was achieved.C6 is an ecological alternative to C8(eight CF2 groups)fluorinated compounds,and it was thereafter successfully incorporated into aramid fabric to achieve a durable superomniphobic surface.The fabric became water and oil repellent with an extremely high water contact angle of 180°.As tested by the water spray AATCC test and hydrocarbon resistance test,the as-prepared fabric gained 100°(ISO 5)and grade number 4 respectively.Furthermore,the fabrics also showed significantly improved washing durability after ten washing cycles.By scanning electron microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR)and x-ray photoelectron spectroscopy(XPS)tests,it is indicated that the durable superomniphobicity can be attributed to the roughness and activation of the aramid surface by the plasma pre-treatment,which induces more adsorption and chemical graft of the C6 copolymer.