Effect of Relative Humidity on Mycelial Growth of Cercospora canescens

The relative humidity studies revealed that maximum mycelial of fungus was observed at 90 per cent relative humidity (89.00 mm), which was followed by 100 per cent (86.30 mm). The least mycelia growth was observed at 50 per cent (45.30 mm). A significant decrease in mycelium growth was observed at 80, 70 and 60 per cent (80.40 mm, 70.20 mm and 57.00 mm) humidity level, respectively. Each fungus has its relative humidity range for the growth.

Paper-containing 1-methylcyclopropene treatment suppresses fruit decay of fresh Anxi persimmons by enhancing disease resistance

Objectives The purpose of this work was to evaluate the potential application of papers containing 1-methylcyclopropene (1-MCP) postharvest treatment for suppressing fruit decay of fresh Anxi persimmons and its possible mechanism. Materials and methods Anxi persimmon fruit were treated with papers containing 1-MCP at the dosage of 1.35 μL/L and stored at 25 ± 1 °C and 85 per cent relative humidity for 35 days. During storage, the fruit decay rate and lignin content were evaluated, and the content of total phenolics, the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), chitinase (CHI), and β-1,3-glucanase (GLU) were determined by spectrophotometry. Results The 1-MCP–treated persimmons displayed a lower fruit decay rate, but higher contents of lignin and total phenolics, higher activities of PAL, PPO, POD, CHI, and GLU. Conclusions The treatment with 1-MCP could inhibit the fruit decay of postharvest Anxi persimmons, which might be because 1-MCP enhanced fruit disease resistance by increasing the activities of disease resistance-associated enzymes and retaining higher contents of disease resistance-related substances in postharvest fresh Anxi persimmons. These findings indicate that papers containing 1-MCP at the dosage of 1.35 μL/L have potential application in suppressing fruit decay and extending storage life of postharvest fresh Anxi persimmons.

The Dimensional Stability and Durability of Acrylic Resins for the Injection of Cementitious Systems

The dimensional stability and durability of Acrylamide- and Methacrylate-based acrylic resins have been studied. The dimensional stability was characterized by measuring the volume expansion of samples immersed in water for a period up to 240 days or by exposing the samples to 23oC and 50 per cent, 90 per cent relative humidity and by monitoring the shrinkage. The durability was investigated by exposing the resins to cyclic variations of temperature in air and in water. The resins generally exhibit a significant volume change up to 160 per cent of the initial volume when immersed in water or exposed to a relatively dry atmosphere (23oC and 50 per cent). A general increase in the material stiffness and/or crack formation on the surface of the resin is observed. On a long-term basis, the durability of the resins may significantly vary with occasionally a partial or complete deterioration of the some resins. A general better dimensional stability and durability is observed for the Methacrylate-based resins as compared to the Acrylamide-based resins.

Accelerated Ageing Test in Maize: Pattern of Seed Deterioration

The freshly harvested seeds of maize single cross hybrid TNAU maize hybrid CO 6 were kept under accelerated ageing condition by exposing the seeds to 40°C temperature and 100 per cent relative humidity in order to assess the physical, physiological and biochemical changes taking place during storage. This study revealed that minimum germination of 90 per cent as per the Indian Minimum Seed Certification Standards (IMSCS) was reached on 4th day of accelerated ageing and reached 54 percent on 9th day of accelerated ageing against the initial seed germination of 98 per cent. The moisture content was increased from 10.1 per cent to 15.9 per cent on 9th day of accelerated ageing. The root length, shoot length, dry matter production, vigour index, α-amylase, catalase, peroxidase activity and carbohydrate content were decreased. Whereas electrical conductivity of seed leachate and reducing sugars were increased, while advancing the period of accelerated ageing.

Prediction of storability of organically produced paddy seeds through natural and accelerated ageing techniques

The present study was conducted to know the storage potential of organically produced paddy seeds in the Department of Seed Science and Technology, University of Agricultural Sciences, Raichur. The seed lot were divided into two parts, one part was stored in cloth bag for a period of 12 months under ambient conditions. At thesame time another set of seeds were subjected to accelerated ageing at 42 + 10C temperature and 90 per cent relative humidity (RH) for a period of 0-12 days. Among the ageing methods, artificially aged seeds showed drastic decreases in seed quality as compared to natural ageing. Among the treatments T9 (37.5 % FYM + 37.5 % vermicompost + 25 % neem cake + foliar spray of panchagavya on 30, 60, 90 and 120 DAT) recorded significantly highest seed quality parameters viz., seed germination (97.81 %), seedling length (29.42 cm) and SVI (2878) at initial stage in both the method of aging and at the end of storage period; seed germination (71.23 and 87.33 %), seedling length (19.66 and 27.00 cm) and SVI (1400 and 2358) in accelerated ageing (AA) and natural ageing (NA) respectively, whereas, lowest in control (Inorganic treatment). The seed quality parameters of four days of AA were similar to that of six months of NA. Hence, storability of organically produced paddy seeds were better as compared to inorganic seeds and it can be predicted that four days of AA is equal to six months of NA. The information generated will be useful in retention or disposal of a particular variety or seed lot.

Thermodynamic analysis of the apple drying process

This paper is concerned with thermodynamic analysis of the process of single-layer drying of apple slices by means of a cyclone-type dryer. Using the first law of thermodynamics, energy analysis was performed to estimate the ratios of energy utilization throughout the drying process. Exergy analysis was carried out to determine exergy losses during the drying process by applying the second law of thermodynamics. It was concluded that the exergy losses increased with increasing energy utilization in both trays and the drying chamber. Values of the energy utilization ratio (EUR) of the drying chamber varied in the range 0−41.64 per cent depending on the drying conditions. The most exergy losses took place on the first tray (EUR = 0−21.06 per cent) during the drying of apple slices. It is emphasized that apple slices are sufficiently dried in the range 60−80°C with 20−10 per cent relative humidity and a drying air velocity of 1.5 m/s over a 3.33−5.33 h period in spite of exergy losses of 0−1.243 kj/s (EUR = 0−34.72 per cent).

Measuring the tensile strength of caked sugar produced from humidity cycling

The aim of this study was to develop moisture migration modelling in stored sugar due to the temperature cycling of the storage environment. This was done by forming cake of sugar in a gas-bearing tensile tester. The sugar and tester were enclosed in a controlled humidity system and the relative humidity was cycled between four hours at 70 per cent relative humidity and four hours at 20 per cent relative humidity. Liquid bridges formed between the sugar particles at high relative humidity, with the bridges hardening subsequently when the humidity was reduced. It was found that the relationship between the tensile strength and number of cycles could be approximated by the relationship σT = K √ N and the agglomerate tensile strength was in the order of 150Pa after 32 cycles. This suggests a soft cake rather than hard cakes with a tensile strength of twice this order of magnitude, which are formed, for example, in salt. A value of 1300kPa was obtained for the parameter representing the average strength of the bridge material in a simplified model of monosized spheres linked by pendular bridges in a system of uniform packing.

A study of the influence of humidity on the friction and squeal generation of automotive brake pads

In order to clarify the influence of humidity on the coefficient of friction and brake squeal generation, a series of brake rig tests has been performed. The influence of both air humidity and pad humidity was evaluated. The results show that, between 20 and 80 per cent relative humidity, air humidity has a limited influence on the coefficient of friction. Nevertheless, in a humid atmosphere the friction coefficient was considerably lower than in a wet environment for two of the pads and higher for one pad. This is believed to be an effect of different mechanisms of tribofilm formation on the pad surfaces. The tribofilm observed on the pads mainly consists of iron oxide originating from the disc. The film is more easily formed in dry environments and preferentially by the pads with low metal content. The friction increase often seen during each individual stop is slightly lower at high air humidity. This effect is more pronounced for the pads with high metal content. Generally, the pads with smooth surfaces were less sensitive to changes in humidity. Only a limited correlation was found between relative humidity and brake squeal generation. One of the pads generated considerably more squeal in low humidity. None of the pads showed the opposite behaviour.

Effect of inoculation method on rhizobium survival and plant nodulation under adverse conditions

In a series of experiments, different inoculation methods applied to seeds of Glycine wightii were compared for their effect on survival of rhizobia (Rhizobium sp.) under various conditions: high temperature with and without high relative humidity, exposure to sunlight, and contact with superphosphate. Seeds were inoculated with peat inoculum in gum arabic (gum treatment), in gum arabic plus a coating of lime or rock phosphate, or with peat inoculum in water (slurry). When subjected to 50�C for eight hours a day, survival of the cowpea-type Rhizobium strain CB756 was poorer at 75 per cent relative humidity than at 40 per cent. CB756 survived better than the clover strain TA1 under high temperature and high relative humidity, and neither lime nor phosphate pelleting increased survival of the two strains over the gum treatment. Poorest survival was with phosphate for TA1 and lime for CB756. When exposed to sunlight, numbers of CB756 fell most rapidly in the gum treatment but, after a longer period in a glasshouse at about 30�C, survival was poorest in the slurry treatment. When mixed with superphosphate, lime pelleting resulted in best survival of both strains. In pot experiments, lime pelleting resulted in a higher percentage of nodulated plants and higher plant weights of Trifolium subterraneum and Glycine wightii, the advantage being greatest when low numbers of rhizobia were on the seed at sowing.

Bionomics of Agrilus acutus (Thnb.) (Col., Buprestidae) on mesta (Hibiscus cannabinus) in India

An account is given of the life-history of Agrilus acutus (Thnb.) (Buprestidae), a pest of ‘mesta’ (Hibiscus cannabinus) in india. The eggs are ovate and scale like, and are laid singly on the stem, usually near a leaf scar, and when kept at 31°C. and 73 per cent. relative humidity hatched on average in 12.4 days. The larva bores through the lower surface of the egg directly into the stem and feeds under the bark forming a sprial tunnel. A raised weal develops on the surface of the stem overlying the tunnel. Before each moult, the larva bores into the wood and makes a vertical chamber in which moulting occurs. There are normally three moults in the active feeding stages, but exceptionally four, and a prepupal moult. The rate of tunnelling is at first about 56 mm. per day and later eaches about 107 mm. The larval stage lests 26 days. The fully grown larva is 21 mm. long and bores into the wood to pupate, making a pupal chamber 11 mm. long into which it fits itself by adopting an asymmetrical U-shaped posture. After a prepupal stage of 2.5 days it pupates. The pupal period occupies about 11.7 days and a further seven days are spent by the adult in the pupal chamber. The adult female mates within a day of emergence from the stem. but does not oviposit until at least seven days have elapsed.