Lifetime estimation of glass reinforced epoxy pipes in acidic and alkaline environment using accelerated test methodology

Accelerated ageing test methodology is valid and widely accepted procedure for estimating the lifetime of isotropic homogeneous polymeric materials. However for non-isotropic and heterogeneous polymeric compounds such as glass reinforced epoxy (GRE) pipes, accelerated ageing test methodology has not been much investigated. Various standards such as ASTM D 3681, ASTM D 5365 are being used to estimate the lifetime of GRE pipes using regression analysis which is time consuming, and requires large number of test specimens and fixtures specific to pipe dimensions. Accelerated ageing test methodology can be a viable method for estimating the lifetime. The research on accelerated test methodology as a vital tool to determine the lifetime of GRE pipes has been limited. The major concern for using accelerated ageing test methodology is primarily due to the degradation kinetics of the anisotropic composite materials which may not be governed by the Arrhenius principle. The present study on the estimation of lifetime of GRE pipes in extreme acidic and alkaline medium reveals that degradation of the composite pipe follows the Arrhenius principle and the degradation mechanism can be described by first order reaction kinetics. The degradation rate, the temperature dependence of the degradation rate and lifetime of the glass reinforced epoxy pipes in extreme acidic and alkaline medium as found in the current study are presented here, along with the morphological study of aged and un-aged GRE pipes.     

Landraces-potential treasure for sustainable wheat improvement

Genetic Resources and Crop Evolution - Agricultural production is facing serious threat from various biotic and abiotic stresses specifically under climatic challenges. It is becoming increasingly...     

Storage and high conversion frequency of encapsulated protocorm-like bodies of Cymbidium devonianum (orchid)

Summary

A method for the storage and high frequency conversion of Cymbidium devonianum protocorm-like bodies (PLBs) is reported. To study the effect of nutrient level on storage, PLBs were encapsulated in calcium alginate beads supplemented with 1.0×, 0.5×, 0.25×, or 0.125× Murashige and Skoog (MS) basal medium containing 0.3% (w/v) sucrose, without agar in the encapsulating matrix, and stored at room temperature (25º ± 2ºC) in the dark. Beads containing 0.25× MS were also kept at different temperatures (0ºC, 4ºC, 8ºC, or room temperature) in the dark to ascertain the optimal temperature for storage. One set of controls (i.e., non-encapsulated PLBs) was maintained for each treatment. The survival and subsequent percentage conversion values of PLBs were assessed at 30 d storage intervals after culturing on MS regeneration medium. Compared to the controls, all encapsulated PLBs showed improved storage at room temperature. In all treatments, non-encapsulated PLBs did not survive, but turned brown and died. Encapsulated PLBs in 0.25× MS medium could be stored for 90 d at room temperature without any significant loss in viability. However, a significant decrease in the survival percentage was recorded after longer storage times. Encapsulated PLBs containing 0.25× medium could be stored at 4ºC and 8ºC for 120 d and 180 d, respectively, without loss of viability. As storage times increased beyond 180 d, the survival percentage of encapsulated PLBs decreased. The conversion of encapsulated PLBs led to the emergence of regenerated plantlets. Initially, small green globular outgrowths from the PLBs were observed on the surface of the beads. These outgrowths multiplied to form clusters of PLBs which then regenerated into plantlets. In both studies, more prolonged storage of encapsulated PLBs increased the time interval for germination and plantlet regeneration on MS regeneration medium. Similarly, decreases in both basal MS strength in the matrix, and in storage temperature, resulted in an increase in the time required for germination and plantlet regeneration. Plantlets that regenerated from stored, encapsulated PLBs were hardened-off, and a high survival percentage (90%) was obtained in a glasshouse.     

Characterization of the effect of a QTL for drought resistance in rice, qtl12.1, over a range of environments in the Philippines and eastern India

A large-effect QTL for grain yield under drought conditions (qtl12.1) was reported in a rice mapping population derived from Vandana and Way Rarem. Here, we measured the effect of qtl12.1 on grain yield and associated traits in 21 field trials: ten at IRRI in the Philippines and 11 in the target environment of eastern India. The relative effect of the QTL on grain yield increased with increasing intensity of drought stress, from having no effect under well-watered conditions to having an additive effect of more than 40% of the trial mean in the most severe stress treatments. The QTL improved grain yield in nine out of ten direct-seeded upland trials where drought stress was severe or moderate, but no effect was measured under well-watered aerobic conditions or under transplanted lowland conditions. These trials confirm that qtl12.1 has a large and consistent effect on grain yield under upland drought stress conditions, in a wide range of environments.     

Carbon and Nitrogen Amendments Lead to Differential Growth of Bacterial and Fungal Communities in a High-pH Soil

Microbial growth in soil is mostly limited by lack of carbon (C). However, adding fresh, C-rich litter can induce nitrogen (N) limitation. We studied the effect of alleviating C and N limitation in high-pH (> 8) soils, soils expected to favor bacterial over fungal growth. Nitrogen limitation was induced by incubating soils amended with C-rich substrate (starch or straw) for 4 weeks. Limiting nutrients and the effects of alleviating limitation were then studied by adding C (as glucose) or N (as NH₄NO₃) and measuring microbial growth and respiration after 4 d. In non-amended, C-limited soils, adding C but not N increased both microbial respiration and bacterial growth. In N-limited, substrate-amended soils, adding C increased respiration, whereas adding N increased both microbial respiration and growth. Inducing N limitation by amending with straw was most easily detected in increased fungal growth after the addition of N, whereas with starch, only bacterial growth responded to alleviating N limitation. Compared to earlier results using a low-pH soil, the effect of substrate used to induce N limitation was more important than pH for inducing bacterial or fungal growth after alleviating N limitation. Furthermore, we found no evidence that alleviating N limitation resulted in decreased respiration concomitant with increased microbial growth in soil, suggesting no drastic changes in C use efficiency.     

Removal of Trinitrotoluene with Nano Zerovalent Iron Impregnated Graphene Oxide

Nano zerovalent iron (nZVI) impregnated reduced graphene oxide (nZVI-rGO) hybrid was prepared via gaseous hydrogen reduction of anhydrous iron(III) chloride (FeCl₃) on the surface of thermally exfoliated reduced graphene oxide (rGO) nanosheets without using any toxic reducing agent, surfactant, or stabilizing agent. Characterization of prepared samples was carried out using various techniques. Morphological study showed that prepared rGO possesses a few-layered wrinkled paper-like structures and nZVI particles of ~?30 nm size were homogeneously dispersed on the surface of rGO nanosheets. Fourier transform infrared (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometry (EDS) analyses indicated that oxygen-containing functional groups decreased in the order of graphite oxide (GO) > rGO > nZVI-rGO. Removal studies of trinitrotoluene (TNT) were carried out using graphite (G), GO, rGO, and nZVI-rGO with the aid of high-performance liquid chromatography (HPLC). Kinetic models were applied to establish the rate and mechanism of adsorption of TNT on different adsorbents, and intraparticle diffusion model based on initial adsorption characteristics was employed to ascertain mechanism of film and intraparticle diffusion in the adsorption process. The removal rate and adsorption capacity was found to be highest for nZVI-rGO, which renders this adsorbent to be a potential futuristic adsorbent for removal of explosives.

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Graphical Abstract ?

     

Evaluation of direct and indirect measures of quarter milk from crossbred buffaloes

Somatic cell count (SCC), bacteriological findings and electrical conductivity (EC) were measured in milk from 216 quarters of 54 Murrah crossbred buffaloes for characterization of buffalo milk. Mean SCC in normal, subclinical and clinical mastitic milk was 171, 799 and 6039 × 10³/mL, respectively. Coagulase negative Staphylococci (CNS) were the major organisms associated with subclinical mastitis, whereas CNS and coliforms were the predominant organisms in clinical mastitis. EC values were found to be significantly higher in buffalo milk with mammary infection. The best trade-off between sensitivity and specificity for diagnosing mastitis in buffaloes by EC score was found at the cut-off value of 3.7 mS/cm. The direct measures such as SCC, EC, bacteriological findings, and appearance of milk were found to be useful for the evaluation of udder health of buffaloes and categorization of milk.     

Definitive Callose Deposition in Tapping Panel Dryness Affected Bark of Hevea brasiliensis

The structural and functional aspects of sieve elements in Tapping Panel Dryness (TPD) affected bark of Hevea brasiliensis, with special reference to definitive callose deposition, have been studied using histochemical methods. The effect of ethephon in definitive callose deposition in TPD affected bark also has been investigated, as the ethylene is reported to have a major role in TPD. The phloem of Hevea is characterized by sieve elements with compound sieve plates. The deposition of definitive callose on the sieve areas following TPD limits the translocation of sap through sieve elements. The amount of functional phloem was narrow and the accumulation of definitive callose was more in the sieve elements of TPD affected bark compared to that of unaffected bark of the same tree and of healthy trees. The affected area showed an increment in deposition of definitive callose in both vertical and horizontal extent of sieve areas; and there was a reduction in length of sieve plate, density of sieve pores, length of inter-sieve area wall, and number of sieve element rows in the inner bark. The lateral walls of non-functional sieve elements became thick and lignified. The anatomical changes in the sieve elements of TPD affected bark suggest that the translocation of phloem sap is regulated by deposition of definitive callose and less differentiation of sieve elements from vascular cambium. The external application of ethephon on bark enhanced the definitive callose deposition on sieve elements. The findings from the study reveal that ethylene plays a major role in the senescence of sieve elements.