Fabrication of Crack-Free Flattened Bamboo and Its Macro-/MicroMorphological and Mechanical Properties

This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.

Study on Preparation of Lignin-Containing Nanocellulose from Bamboo Parenchyma

Bamboo vascular bundle fiber and parenchyma(BP)are separated by high-temperature treatment with saturated steam.Bamboo vascular bundle fiber is widely used in the market,but how to develop and utilize parenchyma tissue is a difficult problem.The sulfated cellulose nanofibers(ANFs)were obtained by sulfating BP with a deep eutectic solvent(DES),which provided a theoretical basis for the value-added utilization of BP.Using DES as the reaction medium and reagent,the BP was grafted with a sulfonic acid group to form a gel substance in water,ANFs and nanocellulose gel were obtained by ultrasonic cell crusher.The highest yield of ANFS was 75%.The width of the ANFs was about 3 nm,and a small number of nanofiber aggregates existed at the same time.A high aspect ratio of ANFs,due to their high viscosity,has potential applications as enhancers at low concen-trations.Lewis acid(ZnCl 2)added based on binary(DES)greatly improved the thermal stability of the ANFs and maintained the crystal form of cellulose I.

DYNAMICS OF SIS EPIDEMIC MODEL WITH THE STANDARD INCIDENCE RATE AND SATURATED TREATMENT FUNCTION

An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the population are also studied. We find that the effect of the maximum recovery per unit of time and the recruitment rate of the popula- tion over some level are two factors which lead to the backward bifurcation, and in some cases, the model may undergo the saddle-node bifurcation or Bogdanov-Takens bifurca- tion. It is shown that the disease-free equilibrium is globally asymptotically stable under some conditions, Numerical simulations are consistent with our obtained results in the- orems, which show that improving the efficiency and capacity of treatment is important for control of disease.

Chaos detection in SIR model with modified Beddington–De Angelis type incidence rate and saturated treatment

In this paper, we construct an SIR epidemic model with a modified Beddington–DeAngelis type incidence rate and saturated treatment rate. We modify the incidence rateto incorporate the isolation of infected individuals after detection, and separation of somesusceptible individuals from the rest to avoid the infection, without an increase in thenumber of classes. We find that the system has a unique disease-free equilibrium (DFE)which is locally asymptotically stable when the reproduction number is less than unity.The multiple endemic equilibria may exist irrespective of the basic reproduction number.The existence of bistability is encountered. Supercritical transcritical (forward), as wellas subcritical transcritical (backward) bifurcation, may occur at R0 = 1 where contactrate, β = β∗ acts as the bifurcation parameter. Therefore, DFE need not be globallystable. The conditions for the existence of Andronov–Hopf bifurcation are deduced withmaximum treatment capacity, c = c0 as the bifurcation parameter. The impacts of isolation of confirmed infected cases and separation of some susceptible from rest are studiednumerically as well as the effect of saturation in treatment. The existence of chaoticbehavior is deduced by showing the maximum Lyapunov exponent to be positive as wellas the sensitivity to initial conditions. The computation of the Kalpan–Yorke dimensionto be fractional confirms the existence of fractal-type strange attractor. The positiveKolmogorov–Sinai entropy further strengthens the claim of the existence of chaos.

Transmission dynamics of onchocerciasis with two classes of infection and saturated treatment function

A mathematical model describing the epidemic interactions between humans and blackflies in the transmission of onchocerciasis is considered.In this model,the onchocerciasis infected human individuals are divided into two classes of infected humans with high and low microfilarial output incorporating saturated treatment function,which caters for high saturation of onchocerciasis disease.We analyze the model feasible region and obtain the basic reproduction number(R_(hb))using the next generation matrix method.Also,we obtain the onchocerciasis-free and onchocerciasis endemic equilibrium solutions and show that if R_(hb) is less than unity,the onchocerciasis-free equilibrium is locally and globally asymptotically stable.Furthermore,we employed a Lyapunov function to analyze the global asymptotic stability of the onchocerciasis—endemic equilibrium whenever Rhb is greater than unity.In addition,data on mass drug distribution of ivermectin drug to combat onchocerciasis prevalence in Ekiti state of Nigeria were fitted to the model.Graphical results reveal that consistent annual or bi-annual distribution of ivermectin drug in the region is effective in reducing the disease menace.Further simulations also show that public health control measures are needed to minimize infectious contact between humans and blackflies which leads to onchocerciasis infections and visual blindness.

Global analysis of a network-based SIR epidemic model with a saturated treatment function

In this paper,we study a network-based SIR epidemic model with a saturated treatment function in which a parameterαis introduced to measure the extent of the effect of the infected being delayed for treatment.Our aim is to present a global analysis and to investigate how the parameterαaffects the spreading of diseases.Our main results are as follows:(1)In the case of the threshold value R_(0)<1,there exist two values of α:α_(c) and α_(0),such that the disease-free equilibrium is globally asymptotically stable when α≤α_(0) and multiple endemic equilibria exist when α≥α_(0).This means that the parameterαhas an essential infuence on the spreading of the disease.(2)In the case of the threshold value R_(0)>1,if the model has only one endemic equilibrium,then the unique endemic equilibrium is globally attractive.In this case,it is also proved that if α≤α_(c),then the endemic equilibrium has only one,so is globally attractive,In addition,numerical simulation is performed to illustrate our theoretical results.