scholarly journals Toxicity of Metals to a Freshwater Ostracod:Stenocypris major

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Shuhaimi-Othman ◽  
Nadzifah Yakub ◽  
Nur-Amalina Ramle ◽  
Ahmad Abas
Keyword(s):  
Laboratory Conditions ◽  
Freshwater Crustacean ◽  
Mn Concentrations

Adults of freshwater ostracodStenocypris major(Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT50) and concentrations (LC50) were calculated. LT50and LC50increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration inS. majorincreases with exposure to increasing concentrations, and Cd was the most toxic toS. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC50values for metals for this species with those for other freshwater crustacean reveals thatS. majoris equally or more sensitive to metals than most other tested crustacean.

scholarly journals Toxicity of Metals to a Freshwater Snail,Melanoides tuberculata

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
M. Shuhaimi-Othman ◽  
R. Nur-Amalina ◽  
Y. Nadzifah
Keyword(s):  
Concentration Factor ◽  
Soft Tissues ◽  
Toxic Metal ◽  
Freshwater Snail ◽  
Freshwater Snails ◽  
Freshwater Gastropods ◽  
Melanoides Tuberculata ◽  
Laboratory Conditions ◽  
Mn Concentrations

Adult freshwater snailsMelanoides tuberculata(Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50and LC50increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L−1, respectively. Cu was the most toxic metal toM. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration inM. tuberculataincreases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50values for metals for this species with those for other freshwater gastropods reveals thatM. tuberculatais equally sensitive to metals.

Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae)

2011 ◽  
Vol 27 (10) ◽  
pp. 879-886 ◽  
Author(s):  
Mohammad Shuhaimi-Othman ◽  
Nadzifah Yakub ◽  
Nur Shahirul Umirah ◽  
Ahmad Abas
Keyword(s):  
Laboratory Conditions ◽  
Median Lethal Concentrations ◽  
Mn Concentrations

Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC50) were calculated. LC50 increased with the decrease in mean exposure times, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC50 values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.

Human drug taking under controlled laboratory conditions.

1988 ◽  
Author(s):  
Marian W. Fischman ◽  
Richard W. Foltin ◽  
Joseph V. Brady
Keyword(s):  
Laboratory Conditions

Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles— Part I: Multiple recycling of corrugated base paper

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 631-638
Author(s):  
FREDERIC KREPLIN ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL
Keyword(s):  
Compression Test ◽  
Production Capacity ◽  
Strength Properties ◽  
Paper Properties ◽  
Corrugated Board ◽  
Laboratory Conditions ◽  
Base Paper ◽  
Study Results ◽  
Short Span ◽  
Multiple Recycling

Paper for recycling is an important fiber source for the production of corrugated base paper. The change in production capacity toward more and more packaging papers affects the composition of paper for recycling and influences the paper quality. This research project investigated the influence of the multiple recycling of five different corrugated base papers (kraftliner, neutral sulfite semichemical [NSSC] fluting, corrugating medium, testliner 2, and testliner 3) on suspension and strength properties under laboratory conditions. The corrugated board base papers were repulped in a low consistency pulper and processed into Rapid-Köthen laboratory sheets. The sheets were then recycled up to 15 times in the same process. In each cycle, the suspension and the paper properties were recorded. In particular, the focus was on corrugated board-specific parameters, such as short-span compression test, ring crush test, corrugating medium test, and burst. The study results indicate how multiple recycling under laboratory conditions affects fiber and paper properties.

Mechanoactivation Of Rice Husk Ash In Laboratory Conditions

2019 ◽  
pp. 20-26
Keyword(s):  
Mechanical Activation ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Silicon Oxide ◽  
Rice Husk Ash ◽  
Pozzolanic Activity ◽  
Maximum Solubility ◽  
Laboratory Conditions ◽  
Before And After ◽  
Mineral Additive

In many rice producing countries of the world, including in Vietnam, various research aimed at using rice husk ash (RHA) as a finely dispersed active mineral additive in cements, concrete and mortars are being conducted. The effect of the duration of the mechanoactivation of the RHA, produced under laboratory conditions in Vietnam, on its pozzolanic activity were investigated in this study. The composition of ash was investigated by laser granulometry and the values of indicators characterizing the dispersion of its particles before and after mechanical activation were established. The content of soluble amorphous silicon oxide in rice husk ash samples was determined by photocolorimetric analysis. The pizzolanic activity of the RHA, fly ash and the silica fume was also compared according to the method of absorption of the solution of the active mineral additive. It is established that the duration of the mechanical activation of rice husk ash by grinding in a vibratory mill is optimal for increasing its pozzolanic activity, since it simultaneously results in the production of the most dispersed ash particles with the highest specific surface area and maximum solubility of the amorphous silica contained in it. Longer grinding does not lead to further reduction in the size of ash particles, which can be explained by their aggregation, and also reduces the solubility of amorphous silica in an aqueous alkaline medium.

The study of oleander scale (Aspidiotus nerii Bche) and the way of diluting its entomophages in Azerbaijan

2014 ◽  
Vol 25 (3-4) ◽  
pp. 69-76
Author(s):  
G. A. Mustafayeva
Keyword(s):  
Weather Conditions ◽  
Young Female ◽  
Potato Tubers ◽  
Chilocorus Bipustulatus ◽  
Laboratory Conditions ◽  
Specific Composition ◽  
Mediterranean Countries ◽  
White Peach Scale ◽  
Rhyzobius Lophanthae ◽  
The Way

Scales (Hemiptera, Diaspididae) are the dangerous crop and park-ornamental plant pests. They reproduce very quickly and cause great harm to plants, sometimes even lead to their complete destruction. Scales suck juices from plants, cause premature drying, dying and falling off leaves, dry branches, deformation of leaves, fruits and shoots, reducing annual growth of plants. Therefore the fight with these pests is rather topical in the agriculture. In this connection in this work the analysis of bioecological peculiarities of oleander scale on the territory of Azerbaijan, and also the detection of species content of parasites and predators, which regulate their number is conducted. We will mark that oleander scales in the wild there are the entomophages are vermin and predators that reduce their quantity. For realization of biological fight against people we studied the bioenvironmental features of wreckers, and also educed specific composition of vermin and predators that regulate their quantity. In a biological fight against these wreckers, one of basic questions is study of specific composition of these entomophages. The faunistic material on entomophages of this pest was collected from different biocenosis; the researched works were conducted in the laboratory and field conditions in Azerbaijan. The advanced and research studies that we conducted gave an opportunity to educe entomophages oleander scale that inflicts an enormous damage to the agricultural cultures and park-decorative plants. The method of breeding of effective types of entomophages is studied in laboratory terms. Firstly the biology of oleander scale on Apsheron peninsula and in Guba Khachmazskii area was studied. The results of long-term studies showed that oleander scale, having distributed on Apsheron peninsula, on olive trees gives 3 generations. Only adult female animals and maggots of I and II age spend winter. Awakening of the scales on olives takes place in March-April. In II and III decade of April the male animals begin their flight. In Guba Khachmazskii area the biology of this scale, dwelling on oleander bush was studied. On this plant the scale gives 3 generations. Young female animals, and also maggots of I and II age winter. As a result of the works conducted the following entomophages of oleander scale were detected: predator Rhyzobius lophanthae Blaisd, Chilocorus bipustulatus L., Chilocorus renupustulatus L; parasites: Aphytis chilensis Howаrd, Aspidiotiphagus citrinus Graw, Encarsia aurantii (Howard). The habitat of Rhyzobius lophanthae is Australia. At the end of the last century of this predatory beetle left to California, from there left to Italy and in other Mediterranean countries. In 1947 by chance was left to Georgia (Abkhazia). Maybe these useful predators in Azerbaijan were from Georgia. For diluting the entomophages from the local indigenous fauna the potato tubers were used, on which firstly the oleander scales, and then road-beetles Rhyzobius lophanthae, Chilocorus bipustulatus reproduced themselves. In the laboratory conditions the methods of diluting of these Coccinellidae was developed. Thus, firstly the way of diluting parasites of oleander scale was studied and developed – Aphytis chilensis Howard, Aspidiotiphagus citrinus Graw и Encarsia antantii (Howard). It was detected that predatory entomophage-chilocor in the natural conditions is ineffective, as their maggots and chrysalises are affected by other local parasites. In the laboratory conditions this beetle produce itself very well on the potato tubers, infected by oleander scale. However, we should note that among entomophage parasites Aphytis chilensis plays the huge role in destruction of scales. In dependence on the weather conditions this macrophage in the nature can give 3–4 generations. Also it was proved that beetle Rhyzobius lophanthae in the biological fight can be applied against all round scales. This predator is effective entomophage of oleander, olive scale, black pine-leaf scale, white peach scale, European fruit scale and cactus scale. In connection with this, Rhyzobius lophanthae can be applied in the biological fight against oleander scale and presently is irreplaceable and perspective entomophage. 

Direct shear strength test on rocks along discontinuities, under laboratory conditions

2014 ◽  
Vol 9 (3) ◽  
pp. 139-150 ◽  
Author(s):  
Ildikó Buocz ◽  
Nikoletta Rozgonyi-Boissinot ◽  
Ákos Török ◽  
Péter Görög
Keyword(s):  
Shear Strength ◽  
Strength Test ◽  
Direct Shear ◽  
Shear Strength Test ◽  
Laboratory Conditions
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