Bag Technique Research Articles

Face Mask Recognition for Covid-19 Prevention

In recent years, the COVID-19 pandemic has negatively impacted all aspects of social life. Due to ease in the infected method, i.e., through small liquid particles from the mouth or the nose when people cough, sneeze, speak, sing, or breathe, the virus can quickly spread and create severe problems for people’s health. According to some research as well as World Health Organization (WHO) recommendation, one of the most economical and effective methods to prevent the spread of the pandemic is to ask people to wear the face mask in the public space. A face mask will help prevent the droplet and aerosol from person to person to reduce the risk of virus infection. This simple method can reduce up to 95% of the spread of the particles. However, this solution depends heavily on social consciousness, which is sometimes unstable. In order to improve the effectiveness of wearing face masks in public spaces, this research proposes an approach for detecting and warning a person who does not wear or misuse the face mask. The approach uses the deep learning technique that relies on GoogleNet, AlexNet, and VGG16 models. The results are synthesized by an ensemble method, i.e., the bagging technique. From the experimental results, the approach represents a more than 95% accuracy of face mask recognition.

Diagnosis of pneumonia in the lungs in the conditions of the COVID-19 pandemic using ensemble learning methods

Chest X-ray (CXR) images play a significant role in the diagnosis of COVID-19 disease in pandemic conditions. However, one of the main problems in determining whether COVID-19 is negative or positive in medical imaging is that the classification models are prone to high false detection rates. The article proposes a system that can accurately assign chest X-ray images of COVID-19 to the appropriate COVID-19 and normal classes. The proposed system consists of two parts: 1) module for feature extraction from images; 2) ensemble learning module that performs the classification of images. Comparative analysis of the proposed approach with the existing methods is provided in numerous experiments, and the advantages of the proposed classification model and the feature extraction method from the previous methods are shown. A model as a result of the experiments, distinguished COVID-19 class images from normal images accurately. As ensemble learning strategies the bagging, pasting and AdaBoost techniques are used.

Efficacy of different bagging techniques for the management of litchi fruit borer (Conopomorpha sinensis)

The bagging of fruits is widely used to provide a physical barrier between the fruits and insect pests. Litchi can easily be bagged to keep them safe from oviposition of litchi fruit borer, Conopomorpha sinensis Bradley (Lepidoptera: Gracillariidae). Efficacies of different bagging alone or in combination with insecticides were evaluated against the control trees in a commercial litchi orchard in Bangladesh. The study consisted of five treatments: mosquito net sheets, mosquito net bags, white waxed-paper bags, mosquito net bags combined with Novastar 56 EC (bifenthrin + abamectin) and mosquito net bags combined with neem leaf extracts. Treatments were set at 10, 20 and 30 days after fruit settings (DAFS). Regardless of the bagging method and setting times, all the treatments significantly reduced C. sinensis infestations compared to the control trees. Earlier bagging of fruits (within the 10 days of fruit settings) provided the best protection (100%) from C. sinensis infestations. In the cases of later bagging of fruits (at 20 and 30 DAFS), better defences against C. sinensis were found from the white waxed-paper bagging and mosquito net bags + Novastar 56 EC treatments. Irrespective of the bagging times, higher pest-free fruits (>95%) and benefit-cost ratios (BCR) were achieved from the bagging with white waxed-paper bags (8.25:1) and the mosquito net bags + Novastar 56 EC (5.18:1). Among the treatments, the mosquito net bags, or sheets were less effective. However, mosquito net bags combined with neem leaf extracts provided better outcomes. Therefore, bagging fruits within 10 days of fruit settings can be recommended for better protection. For the delayed bagging, white waxed-paper bags or the mosquito net bags in combination with Novastar 56 EC (preferred) or neem leaf extracts might be suggested.

Rapid synthesis of ZnO nanostructures on woven carbon fiber using microwave treated chemical bath deposition and their characterization

Microwave-assisted chemical bath deposition (MACBD) is a new method for synthesizing metal-oxide layers and nanostructures efficiently. The fast synthesis of ZnO nanostructures (NSs) on woven carbon fiber (WCF) is reported in this study employing the MACBD technique. An aqueous solution of tetra ammonium zinc complex was used to create several morphologies of ZnO NSs on WCF fabric, including nanopetals, twinned nanospheres, nanoflowers, and nanoflakes. Under microwave heating, plain WCF fabric samples were treated with several precursor solutions. When compared to conventional CBD, the development time of ZnO NSs is lowered to roughly 2–4 min. Field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and an X-ray diffractometer were used to evaluate as-developed ZnO NSs morphologies on WCF. The processing of ZnO NSs on the strands of carbon fibers was interpreted using FESEM, and it was discovered that variations in microwave duration and precursor solution are the primary causes of ZnO morphology development. With the formation of nanostructures, the crystalline peak height of the nanostructures increases. For the fabrication of high performance ZnO nanostructured WCF hybrid polymer composites vacuum bagging technique were used along with resin transfer system. Epoxy resin was applied as a matrix material with the five layers of ZnO grown WCF for varied applications.

Influence of nanoclay filler on mechanical properties of CFRP composites

Nanoclay is an innovative nanofiller with appealing qualities such as strong compatibility with a wide range of polymers and excellent mechanical, thermal, and electrical properties. This work reveals the fabrication of carbon fibre reinforced polymer (CFRP) composites by adding various wt % (0, 1.25, 2.50, 3.75) nanoclay in epoxy using the vacuum bagging technique. Mechanical properties such as flexural strength, interlaminar shear strength (ILSS), and tensile strength tests were performed on neat CFRP and nanoclay embedded CFRP composite to determine the effect of adding nanoclay on the mechanical properties of CFRP. The result obtained from these tests concludes an increase in flexural, ILSS, and tensile strength continuously up to 2.5 wt% of nanoclay after further addition of nanoclay, these properties decrease.

Nutritive value of mixed napier grass (Pennisetum purpureum)- Leucaena (Leucaena leucocephala) silage for ruminants

The objectives of the study were to determine the chemical composition, ruminal degradability, and apparent digestibility of mixed Napier (Pennisetum purpureum) (PP) -Leucaena (Leucaena leucocephala) (LL) silages. Freshly cut Napier and Leucaena were harvested and mixed at 70:30; 50:50; 30:70 ensiled for six weeks. The chemical composition of the fresh forages and the silages were determined using the AOAC (1990) procedures. Dry matter (DM) and crude protein (CP) ruminal degradability were determined by nylon bag technique using three rumen cannulated Bonsmara steers for periods of 0, 6, 12, 24, 48, 72, 96 and 120 hours. DM and CP ruminal degradability kinetics were described by fitting the data on the model P= a+b (1-e−ct) using the neway computer program where a is the rapidly degradable fraction, b is the slowly degradable fraction and c is the outflow rate. Hay supplemented with 25% mixed PP: LL silages was fed to three castrated male Pedi sheep to evaluate apparent digestibility coefficient and N retention. The fresh cut PP had more CP, Fat, and ash, with less OM. Leucaena was richer in most nutrients than Napier. The study indicated the 50:50 silage was the optimal mix to maximize the overall nutritive value. The DM and CP disappearance constants a, b and c were similar for all silages. PP: LL mixing ratio did not affect the DM and CP degradability kinetics of the silages. There was no effect on total dietary intake, apparent digestibility and N retention.

Tensile and Stress Analysis of Hybrid Composite Prosthetic Socket Reinforced with Natural Fibers

Natural fibers and their composites are the evolving movements in material science, and with that, the utmost use of plant-based fibers has become the focus of this research. Sisal and cotton natural fibers were used to construct a prosthetic socket as an attempt to substitute material currently available in the manufacturing of sockets. The vacuum bagging technique was adopted to produce a below-knee socket. The influence of different fiber layering sequences on the volumetric and mechanical characteristics was estimated experimentally and numerically. Mechanical tensile tests were used to assess laminated specimens, such as tensile strength, young modulus, and elongation percentage. The number and type of reinforcing layers had an effect on mechanical properties, and the best composite specimens were three layers of sisal with two layers of carbon fiber, with tensile strength and modulus of elasticity reaching (261–4760) MPa, respectively. The finite element method (ANSYS- 16.1) was used to anatomize by seeing the contours distribution of safety factor, equivalent Von Mises stress, equivalent Von Mises strain, and total deformation. This procedure was executed by building ten models for the socket, which served as three-dimensional structural composite materials. The results of the present study advocate that the arrangement of natural and synthetic reinforcements allow the preparation of bio-composites with enhanced performance. This work revealed the assets of sisal and cotton fiber hybrid reinforced PMMA resin composites (hybridized at diverse volume percentages and lamination layup), which have not been tried up to now.

Biodegradation behaviour of green composite sandwich made of flax and agglomerated cork

Material experts are striving to use natural resources as skin and core in composite sandwiches to achieve light weight, biodegradability, and cost benefits. This paper reports one such newly developed green composite sandwich and its biodegradable behavior. The skin and core of newly developed sandwich are flax fiber and agglomerated cork respectively. This composite sandwich is manufactured by vacuum bagging technique in order to get higher volume fraction of fiber. The biodegradability testing of the composite sandwich has been executed by soil burial test. The verification of the same has been done using Scanning Electron Microscope (SEM) images, Fourier Transform Infrared Spectroscopy (FTIR) analysis and Thermoanalytical test. The test results portray the percentage of weight loss in the specimens and that, it increases with burial time. It also depicts that the newly developed Green Composite Sandwich (GCS) has 82% higher degradation than the Synthetic Composite Sandwich (SCS) taken for the comparison. SEM images show that the green composite sandwiches have lost their fibrous structure and cell wall surface due to the degradation. FTIR and Thermoanalytical tests also confirm the biodegradability of the developed green composite sandwich.

Vibrational analysis of glass/ramie fiber reinforced hybrid polymer composite

AbstractNatural fiber reinforced hybrid polymer composites have gained extensive applications in recent decades owing to their damping, low density, biodegradability, and low‐cost benefits. This research explores the impact of the surface treatment, and the number of ramie fiber layers on the vibrational and mechanical characteristics of a glass/ramie fiber reinforced hybrid polymer composite. The composite is made of outer layer (glass fiber) and inner layer (ramie fiber) at different concentrations (varying between 2, 3, and 4). The ramie was pre‐treated with sodium hydroxide (NaOH) at different weight percentages (1%, 2%, and 5%). The composites have been fabricated using the vacuum bag technique. The composites have been characterized for chemical, mechanical, morphological, and free vibrational analysis. Fourier transform infrared spectroscopy and scanning electron microscope have been used to study the chemical characteristics and morphological study of the composites respectively. The mechanical properties of the composite were evaluated through tensile and flexural testing. The hybrid composite reinforced with two layers of ramie fiber as the core with 2% pre‐treated shows the maximum tensile strength of 120 MPa and flexural modulus of 12,147 MPa. Overall, the hybridization and NaOH pre‐treatment to certain ratio helps in increase in the hybrid composite's mechanical strength compared to the natural fiber composite.

Studies on cellulases of some cellulose-degrading soil fungi.

In this study, novel cellulolytic fungal strains were isolated, purified, and identified. The ability of these isolates to biodegrade cellulosic materials was examined. The potential of the isolates to produce cellulolytic enzymes and optimize the cellulose degradation process was also investigated. The nylon net bag technique was used to separate cellulose-degrading fungi from soil. A total of 37 species were isolated and tested for their capacity to break down rice straw as a cellulose source. Qualitative assays for cellulase were carried out by Congo red plate assay, while quantitative assays were carried out using the dinitrosalicylic acid (DNS) method at 546nm. Following morphological and molecular identification, the isolates that exhibited the highest cellulase activities were identified as Neurospora intermedia (Assiut University Mycological Center (AUMC) 14359), Fusarium verticillioides (AUMC 14360), and Rhizopus oryzae (AUMC 14361). For N. intermedia, the optimal conditions for maximum activity were a 2% carboxymethylcellulose (CMC) concentration, beef extract and peptone as nitrogen sources, pH 7, 30°C, and an inoculum size of 2.5 (v/v). For F. verticillioides, the optimal conditions were 2.5% CMC concentration, yeast extract as a nitrogen source, pH 6, 30°C, and an inoculum size of 2 (v/v). For R. oryzae, the optimal conditions were 2% CMC concentration, beef extract as a nitrogen source, pH 7, 30°C and an inoculum size of 2.5 (v/v). The identified strains represent new starter strains with high efficiency under optimum conditions for prospective large-scale application in cellulose degradation and nanocellulose production-dependent water purification.

The in vivo crude protein digestibility of soybean species cultivated in Hungary

The purpose of the trial was to use the mobile nylon bag technique to determine the crude protein digestibility and calculate the digestible protein yield of soybean varieties cultivated in Hungary. The trial was carried out with 10, double cannulated (duodenal- and PVTC-cannula) hybrid barrows with initial live weights of 40±3.5 kg. The experimental basal diets were formulated on a corn-wheat-barley-soybean basis according to the requierement of growing pigs (Tybirk, 2015). A total of 20 soybean varieties were tested in this experiment. After simulating gastric digestion the nylon bags were inserted into the duodenum of ten barrows through simple duodenal T-cannulae. Ten bags were administered to each pig daily. A total of 200 (10 samples/soybean variety) bags were inserted over a 4-day period. The mean, standard deviation, minimum and maximum values of the crude protein digestibility of soybean samples were calculated. The protein yields per hectare according to the crop yield and the protein content values and also the digestible protein yield values were calculated. To examine the relationship between crop yield and crude protein yield and also between crop yield and digestible crude protein yield regression analysis were used. The overall results of this experiment indicate that the average crude protein digestibility of the tested soybean varieties was 76.0%, with an absolute difference of 17.3% between the best and the least digestible varieties. ES Mentor variety reached the best digestible crude protein yield, with 1305.4 kg/ha. The variety with the lowest digestible crude protein yield was Boglár, with 752.3 kg/ha. The difference in digestible crude protein yield between these two varieties was 173.5%. In the correlation analysis between digestible crude protein content and yield for soybean varieties our results show that there is no correlation between the two factors. However, Aires, Prestopro, and ES Mentor should be highlighted among the varieties with above trend line results, as they have the best yield (4020 kg/ha; 4100 kg/ha, 4510 kg/ha) and digestible crude protein content (31%, 30.3%, and 28.9%). ES Mentor produced the fourth best digestible crude protein content (28.9%) with the best yield (4510 kg/ha).

The Application of Active Biomonitoring with the Use of Mosses to Identify Polycyclic Aromatic Hydrocarbons in an Atmospheric Aerosol.

The use of biological indicators of environmental quality is an alternative method of monitoring ecosystem pollution. Various groups of contaminants, including organic ones, can be measured in environmental samples. Polycyclic aromatic hydrocarbons (PAHs) have not yet been determined by the moss bag technique. This technique uses several moss species simultaneously in urban areas to select the best biomonitoring of these compounds, which are dangerous to humans and the environment. In this research, a gas chromatography coupled with mass spectrometry was used for the determination of selected PAHs in three species of mosses: Pleurozium schreberi, Sphagnum fallax and Dicranum polysetum (active biomonitoring) and for comparison using an air filter reference method for atmospheric aerosol monitoring. The chlorophyll fluorescence of photosystem II (PSII) was also measured to assess changes in moss viability during the study. As a result of the study, the selective accumulation of selected PAHs by mosses was found, with Pleurozium schreberi being the best bioindicator—9 out of 13 PAHs compounds were determined in this species. The photosynthetic yield of photosystem (II) decreased by 81% during the exposure time. The relationship between PAHs concentrations in mosses and the total suspended particles (TSP) on the filter indicated the possibility of using this bioindicator to trace PAHs in urban areas and to apply the moss bag technique as a method supporting classical instrumental air monitoring.

Mobile bag technique for estimation of nutrient digestibility when hay is supplemented with alternative fibrous feedstuffs in horses

To evaluate the effect of substituting hay with alternative fibrous feedstuffs, the total collection of faeces was used to measure the apparent total tract digestibility (ATTD). Nutrient disappearance and digestion kinetics were examined with the mobile bag technique (MBT) and marker passage measurements. Four caecally-cannulated horses (body weight (BW) 558 ± 32 kg) were used in a cross-over design experiment with two periods of 14 days adaptation and four days of faecal collection. Horses were fed three times a day with either a hay-only (HAY) diet or a mixture of hay:supplement (MIX) (15.1 and 8.4:6.7 g dry matter (DM)/kg BW/day, respectively). The hay used in both treatments (HAY and MIX) was mainly of Timothy and first cut. The MIX supplement diet consisted of oat hulls, alfalfa-, sugar beet pulp- (SBP), grass- and soya hull pellets, each given in 0.44 g DM/kg BW/meal. On day 15 in each period, 20 bags of either hay or SBP and 6–12 bags (1×2x12 cm; 37 µm pore size; 0.5 g feed) of each feedstuff and ytterbium (Yb, 3 g) were placed in the stomach or caecum, respectively. Bags were harvested from the caecum every hour and faeces were checked for bags every fourth hour, collection time was noted and data from the bags were used to estimate pre-caecal, hindgut and total tract nutrient disappearance. Further, faecal subsamples of 300 g were collected, weighed and stored for Yb analysis and further estimation of feed mean retention time. Rate and extent of feed degradation were estimated from the MBT assuming exponential degradation. The ATTD of DM was similar between the two diets (P > 0.05), but the HAY diet had higher ATTD of crude protein (CP) (P = 0.001), neutral detergent fibre assayed with heat-stable amylase and expressed inclusive of residual ash (aNDF) (P = 0.006), acid detergent fibre (ADF) (P = 0.017), hemicellulose (P = 0.001) and celluloseNDF (P < 0.001). The hindgut mean retention time (MRT) for Yb was longer for the MIX than the HAY diet (P < 0.001). No differences for DM, aNDF or ADF digestibility were measured when comparing the ATTD with nutrient disappearance from bags found in the time interval 20–30 h, indicating the ATTD of these nutrients can be predicted by the MBT. The estimated degradation (Dt), but not effective degradation (ED), is preferred when the MBT is used to predict the ATTD. It can be concluded that hay can be substituted partly by fibrous feedstuffs and that the MBT can predict the ATTD of DM, aNDF and ADF in a mixed ration based on MBT measures on individual feedstuffs.

An Enhanced Ensemble of Long Short-Term Memory and Vector AutoRegression for Energy Consumption Forecasting

Objectives: To design and develop an enhanced ensemble model for residential energy consumption prediction using time series analysis. Methods: The system is consistent of an ensemble made from two time series models, which are later combined to produce a final prediction through the use of bagging techniques. The energy profile is built for this study using the data collected from a single-phase Minion Energy Monitor, installed in residential buildings, which is developed by Minion Labs India Private Limited. Samples are collected for a time of 7 days with a two second interval. This data is then restructured and normalized for it to fit the enhanced ensemble model of Long Short-Term Memory (LSTM) and Vector Autoregression (VAR) using bagging techniques and weighted average to obtain the predictions.Findings: The proposed model has produced an enhanced R2 score of 98.99% when compared to LSTM (74.85%), SVM (62.41%), VAR (82.914%) and ARIMA (93.152%) standalone models. It makes use of an analyzed lag variable to reduce computation complexity and resource utilization. Further, an ensemble technique is used to pick out the strengths of two models. An analysis performed showed that this architecture is 6.08% better than the algorithms for LSTM and VAR individually. Novelty: A data driven solution is proposed in this study through the enhancement of existing models to create an ensemble and thereby creating a stable structure that predicts values using a weighted average. The weighted average ensures that precise outputs are obtained by giving more importance to predictions that are closer to the actual values. The use of a lag variable further increases the efficiency, learning rate, dealing with non-linear features, less error and faster training of the proposed architecture. All these factors also aid in improving the accuracy for a time series data prediction. Keywords: Energy Consumption Forecast; LSTM; VAR; Ensemble; Bagging; Artificial Neural Networks; Support Vector Machine

Comparison of Ruminal Degradability, Indigestible Neutral Detergent Fiber, and Total-Tract Digestibility of Three Main Crop Straws with Alfalfa Hay and Corn Silage.

Simple SummaryCorn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS) are the three main crop straws worldwide. Few studies on indigestible neutral detergent fiber (iNDF) and total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of these crop straws are available, which limits their utilization in dairy diets. Here, we compared the ruminal degradability, iNDF288 content, intestinal digestibility, and TTD for the CP, NDF, and ADF of these three crop straws with alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil). The results showed that CS, RS, and WS had higher ruminal potential NDF degradation, intestinal digestible CP, and lower iNDF288 content compared to AH. Greater accuracies for regression equations capable of predicting the iNDF288 content and TTD were also generated based on chemical composition and ruminal degradation kinetics. Incorporating this information into rations could improve our ability to optimize the utilization of main crop straws in balanced dairy diets.Three main crop straws including corn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS), and two forages including alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil) were analyzed in order to compare their ruminal degradability, indigestible neutral detergent fiber (iNDF), intestinal digestibility (ID), and their total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) using both an in situ nylon bag technique and a mobile nylon bag technique. The forage samples were incubated in the rumen for 6, 12, 16, 24, 36, 48, 72, and 288 h, respectively, to determine their ruminal degradability. Prior to intestinal incubation, forage samples were incubated in the rumen for 12 h and 24 h to determine the ruminal degradable content of CP, NDF, and ADF, respectively, and for 288 h to determine their iNDF288 content. Residues from the ruminal undegradable fractions (12 h for CP, 24 h for NDF and ADF) were subsequently inserted into the duodenum through a cannula to determine their intestinal digestible content. Here, the TTD of CP, NDF, and ADF were determined as the ruminal degradable content + intestinal digestible content. The results showed that AH had the highest iNDF2.4 (calculated as acid detergent lignin content × 2.4) and iNDF288 values (379.42 and 473.40 g/kg of NDF), while CS and CSil had the lowest iNDF2.4 values (177.44 and 179.43 g/kg of NDF). The ruminal degradability of CP, NDF, and ADF for CS, RS, and WS were lower than those of AH and Csil during the first 48 h of incubation. The potential degradation fraction of CP, NDF, and ADF for CSil was the highest; CS, RS, and WS were intermediate; and AH was the lowest (p < 0.05). CS, RS, and WS had a lower intestinal digestibility with respect to their rumen undegradable content of NDF (p < 0.05), and lower TTD of CP, NDF, and ADF (p < 0.05) compared to AH and CSil. General regression equations with satisfactory accuracy (R2 ≥ 0.828) were derived to predict iNDF288 and TTD based on their chemical compositions and the ruminal degradation kinetics of different forages. Incorporating this information into rations could improve our ability to optimize main crop straws utilization and milk production.

Effect of Fibre Surface Treatment and Nanofiller Addition on the Mechanical Properties of Flax/PLA Fibre Reinforced Epoxy Hybrid Nanocomposite.

Natural fibre-based materials are gaining popularity in the composites industry, particularly for automotive structural and semi-structural applications, considering the growing interest and awareness towards sustainable product design. Surface treatment and nanofiller addition have become one of the most important aspects of improving natural fibre reinforced polymer composite performance. The novelty of this work is to examine the combined effect of fibre surface treatment with Alumina (Al2O3) and Magnesia (MgO) nanofillers on the mechanical (tensile, flexural, and impact) behaviour of biotex flax/PLA fibre reinforced epoxy hybrid nanocomposites. Al2O3 and MgO with a particle size of 50 nm were added in various weight proportions to the epoxy and flax/PLA fibre, and the composite laminates were formed using the vacuum bagging technique. The surface treatment of one set of fibres with a 5% NaOH solution was investigated for its effect on mechanical performance. The results indicate that the surface-treated reinforcement showed superior tensile, flexural, and impact properties compared to the untreated reinforcement. The addition of 3 wt. % nanofiller resulted in the best mechanical properties. SEM morphological images demonstrate various defects, including interfacial behaviour, fibre breakage, fibre pullout, voids, cracks, and agglomeration.

Mixing effects of three Eurasian plants on root decomposition in the existence of living plant community in a meadow steppe

In grasslands, roots of different plant species decay in combination in the presence of living plants, besides, most root decomposition studies are conducted on how roots of plants decomposed alone or in artificial compositions in the absence of living plants. Therefore, we evaluated how roots of different perennial plants induced effects on decomposition process under living plants and their associated mechanisms. By using litter bag technique, we determined the root decomposition process of three perennial plants, Leymus chinensis, Phragmites australis, and Kalimeris integrifolia grown in monocultures, bi- and tri-species mixtures, after 12 months of incubation under living plants and bare soil communities. We found both additive and non-additive effects on decomposition dynamics indicating that root mass losses of compositions cannot be calculated from decaying rates of individual species. The rich-nutrient roots of K. integrifolia in monocultures and in mixtures with other plant species decayed faster. Compared with bare soil, microbial activities were enhanced under living plant communities and hence stimulated decomposition rates. Our results indicated that microbial activities are important but secondary factors to root physico-chemical properties impacting root decomposition rates. In conclusion, the empirical relationships developed here are helpful to better understand the effects of root properties and microbial activities on decay rates.

Remedial measures for the spring-in effect in L-angled FRP composites

Thermoset based fibre-reinforced composite materials expedite their spreading in various industrial applications for their excellent mechanical properties and chemical inertness. However, one of the major drawbacks of these materials is the difficulty in maintaining the dimensional accuracy of the produced parts. These structural problems are related to the residual stresses generated during the thermal curing process. One of the structural problems manifested is the reduction of enclosed angles of angled sections called spring-in. The present study used the vacuum bagging technique followed by thermal curing to fabricate L-angled glass/epoxy laminates. The direct measurements of spring-in angles were taken using a Coordinate Measuring Machine (CMM). Besides, a Finite Element (FE) model was developed in Abaqus to mimic the curing process. The validity of the developed model has been verified with the experimentally measured spring-in angles. Further, this stabilized model is used to assess the contributions of some influencing factors on spring-in. Based on the findings, a few remedial measures are proposed and verified in this paper. The methods such as mould compensation, optimum stacking sequences, and proper tool selection are effective against spring-in.

Fabrication and characterization of graphene-based de-icing heater

In this study, graphene based paper was utilized as a potential deicing material. Vacuum bagging technique was used to fabricate the composite panel which consisted of graphene based paper and epoxy/glass fiber. The techniques used to fabricate graphene based paper were chemical vapor deposition (CVD) and hot pressing techniques. Scanning electron microscopy (SEM), optical microscopy, X-ray diffraction and Raman spectroscopy were used to characterize graphene based paper and composite panels. The thermal conductivity and electrical conductivity were measured for graphene based paper. The temperature distribution in the composite panel during deicing tests was studied using infrared thermal imaging. The deicing test based on the joule heating of the composite panel by applying electrical potential. Various electrical potential applied to the composite panel to investigate the role of potential applied on the deicing process. Based on the results, the optimum potential applied 5 V was sufficient to remove ice from panel’s surface with low power consumption. The temperature profile of composite panels showed higher temperature for composite panel of CVD graphene-based paper compared by hot pressing sample because of higher in-plane thermal conductivity for CVD graphene-based paper.

Plant‐available soil nitrogen fluxes and turfgrass quality of Kentucky bluegrass fertilized with humic substances

AbstractHigh quality turfgrass requires adequate amounts of nitrogen (N) fertilizer. However, excess N application can increase N losses via leaching and gaseous emissions. Enhanced efficiency fertilizers (EEF) and humic substances have been used to decrease N losses to the environment. A two‐year field experiment was conducted on a native soil with Kentucky bluegrass (Poa pratensis L.) to investigate if the addition of humic substances to fertilizers could be classified as an enhanced efficiency fertilizer. To determine this, the objectives were: a) to determine if incorporating humic substances will increase the plant‐available N collected on ion exchange membranes (IEM) over a growing season and b) to determine the N release (NR) curves of the fertilizer treatments using the mesh bag technique. Fertilizer treatments included humic‐coated urea (HCU), poly‐coated humic‐coated urea (PCHCU), urea + humic dispersing granules (HDG), poly‐coated sulfur‐coated urea (PCSCU), stabilized N, urea, and a nontreated control. Overall, the addition of humic substance to fertilizers did not improve turfgrass quality compared with fertilizers alone. Additionally, all fertilizer treatments had improved turfgrass quality relative to the nontreated control and provided acceptable turfgrass quality for almost all of the growing season. Over the growing season, PCHCU had 25% greater inorganic N captured on IEM compared with all other treatments. Both PCHCU and PCSCU show extended NR curves with PCHCU having a greater release period. In conclusion, PCHCU increased plant‐available N concentrations, released it slowly, and should be classified as an EEF.