Rhyzopertha dominica (lesser grain borer).

Author(s):  
Waqas Wakil

Abstract Females of R. dominica lay between 200 and 500 eggs in their lifetime. The eggs are laid loose in grain. The lowest temperature at which R. dominica can complete development is 20°C; at this temperature, the development from egg to adult takes 90 days. The fastest rate of development occurs at 34°C; at this temperature the egg takes 2 days, the larvae 17 days, and the pupae 3 days to complete development. R. dominica is unable to complete development between 38 and 40°C. Adults live for 4-8 months. Under optimal conditions of 34°C and 14% grain moisture content, there is a 20-fold increase in the population of R. dominica after 4 weeks. It can successfully infest grain at 9% moisture content, but has higher fecundity, a faster rate of development, and lower mortality on grain of a higher moisture content. Adult males produce an aggregation pheromone in the frass that attracts both male and female adults. Adults are good flyers, and can be trapped in pheromone-baited flight traps placed several kilometres from grain stores. Adults can bore into intact kernels. The larvae of R. dominica are mobile.

2005 ◽  
Vol 1 (1) ◽  
pp. 77-93
Author(s):  
Bíborka Gillay ◽  
David B. Funk

The price paid for corn is usually based on 15.0 or 15.5 percent moisture content. However, corn must be dried below 13 percent moisture to ensure safe storage for a year or more. In the U.S., such stored corn cannot be directly remoistened before selling it, but it can be mixed with moist new-crop corn. Accurate moisture measurement of mixtures of dry and moist corn is important to permit adjustment of blending ratios to maximize profitability, but grain moisture meters are less accurate for mixtures of wet and dry grain. This research evaluated the differences between dielectric-type moisture meter results for mixed and equilibrated corn samples at different moisture levels and different measurement frequencies. Equilibrated grain samples tended to give lower moisture results than recently mixed grain samples - especially in the 1 to 10 MHz region. These differences permitted detection of mixtures by using moisture measurements at two frequencies.


Author(s):  
S. Assylbekova ◽  
N. Badryzlova ◽  
L. Kushnikova

The article presents the results of the first research on artificial reproduction in industrial conditions of the endemic, narrow-areal subspecies of Brachymystax lenok Savinovi, which lives in lake Markakol, East Kazakhstan region. The indicators of the heat sum characteristic for each stage of development, the rate of development and growth of the Markakolsky lenok from the moment of pre-breeding to late juveniles are described. To develop technological approaches for artificial fish reproduction, one of the most important points is to determine the optimal conditions for each stage and assess the risks (loss of fish products). At the stage of insemination and transportation of eggs to the place of incubation, the loss was 50 %. The largest losses of fish products were registered during the incubation stage. The most painlessly passed the period of holding and lifting on the float, where the loss was only 3 %. When growing pre-larvae and larvae in the pool, the daily waste did not exceed 1 %. Small-sized animals that were unable to adapt to artificial feeds fell into the waste. Losses during this period amounted to 15 % of the previous stage. In General, the yield of juveniles from the moment of fertilization to the end of the experiment was 16 %. The crucial factor in the development and growth of Lenok Markakolosky is the temperature regime. For the period of embryonic development, the most favorable water temperature is 7–8 °C. From the moment of hatching, the water temperature must be increased to 10–12 °C, and the optimal temperature for the cage growing of fingerlings varies from 12 to 14 °C.


2020 ◽  
pp. 341-350
Author(s):  
Di Wang ◽  
Changbin He ◽  
Haiqing Tian ◽  
Liu Fei ◽  
Zhang Tao ◽  
...  

Low productivity and high electricity consumption are considered problems of the hammer mill, which is widely used in current feed production. In this paper, the mechanical properties of corn grain ground by a hammer mill were analysed, and the key factors affecting the performance of the hammer mill were determined. The single-factor experiment and three-factor, three-level quadratic regression orthogonal experiment were carried out with the spindle speed, corn grain moisture content and number of hammers as experimental factors and the productivity and electricity consumption per ton as evaluation indexes. The results showed that the order of influence on the productivity was spindle speed > corn grain moisture content > number of hammers and that the order of influence on the electricity consumption per ton was corn grain moisture content > spindle speed > number of hammers. The parameters were optimized based on the response surface method with the following results: the spindle speed was 4306 r/min, the corn grain moisture content was 10%, and the number of hammers was 24. The validation experiment was carried out with the optimal parameters’ combination. The productivity and electricity consumption per ton were 988.12 kg/h and 5.37 kW·h/t, respectively, which were consistent with the predicted results of the model.


2018 ◽  
Vol 44 (12) ◽  
pp. 1747 ◽  
Author(s):  
Lu-Lu LI ◽  
Jun XUE ◽  
Rui-Zhi XIE ◽  
Ke-Ru WANG ◽  
Bo MING ◽  
...  

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Waleed H. Hassoon ◽  
Dariusz Dziki ◽  
Antoni Miś ◽  
Beata Biernacka

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.


2021 ◽  
Vol 204 ◽  
pp. 212-222
Author(s):  
Shang Gao ◽  
Bo Ming ◽  
Lu-lu Li ◽  
Rui-zhi Xie ◽  
Ke-ru Wang ◽  
...  

1960 ◽  
Vol 51 (3) ◽  
pp. 599-630 ◽  
Author(s):  
Michael H. Breese

Indications of the type of paddy grain most commonly infested by Sitophilus sasakii (Tak.) and Rhyzopertha dominica (F.) have been obtained from the examination of infested samples of paddy grown in Trinidad, W.I., and in British Guiana.Small-scale experiments with sound mature paddy have shown that S.sasakii is unable to feed and breed in a grain with an intact husk, even when the moisture content is high. It is also probable that R. dominica finds it extremely difficult to attack and infest such grains.The rapid multiplication of S. sasakii in paddy is dependent on there being a high proportion of grains with badly damaged husks. Infestation can occur in grains with a slight separation of the lemma and palea, or with slightly split husks, but the adult that develops is often unable to emerge from such grains.


2021 ◽  
Vol 2107 (1) ◽  
pp. 012059
Author(s):  
A A Almaleeh ◽  
A Zakaria ◽  
M H F Rahiman ◽  
Y B Abdul Rahim ◽  
L Munirah ◽  
...  

Abstract Grain storage is an important part of the post-harvest quality assurance process. The moisture level of the grains during storage is one of the primary problems. The current method of measuring rice grain moisture content is based on random sampling, which is relatively localised, and there is no real-time moisture content measurement available. The RF signal was used to build a new technique for detecting moisture and its presence in rice in real-time in this paper. The mapping of an RF signal, in particular, can be transformed into volumetric tomographic images that can be used to forecast moisture distribution.


Author(s):  
Kobra Tajaddodi Talab ◽  
Mohd. Nordin Ibrahim ◽  
Sergey Spotar ◽  
Rosnita A. Talib ◽  
Kharidah Muhammad

Abstract Glass transition temperatures (Tg) of MR219 rice variety were measured by differential scanning calorimeter (DSC). State diagram was developed and used to evaluate drying process in this study. Glass transition temperatures range of 9.65- 61.79°C were observed for gains with moisture content of 26.8 – 7.4% (w.b.). For mechanical properties and milling test, statistical analysis was performed by using a two factor experiment in completely randomized design (CRD). Two selected factors were drying temperatures at 5 levels (40, 45, 50, 55, and 60°C) and final moisture content (FMC) at 4 levels (10-10.5, 11-11.5, 12-12.5 and 13-13.5%). Three–point bending test was applied to measure the mechanical properties of rice kernel. Generally, bending strength, apparent modulus of elasticity and fracture energy of brown rice kernel increased with decreasing the grain moisture content. Maximum bending strength was 35.69 and 33.64 MPa for 55, and 60°C, respectively. All samples that were dried at 55 and 60°C experienced to go through the glass transition line after reaching their temperature to the room temperature at the end of drying process. The effect of drying temperature, paddy FMC and their interactions on whole kernel percentage (WKP) and mechanical properties were significant (α = 0.05). An inverse relationship was observed between WKP and the percentage of strong kernels for all treatments.


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