Laboratory Method for Determining the Lethal Exposure Time

2009 ◽  
pp. 240-240-6
Author(s):  
CS Nichols ◽  
AC Crabb
Keyword(s):  
Exposure Time ◽  
Laboratory Method

scholarly journals Kemampuan Biosorpsi Dan Pertumbuhan Rumput Laut Gracilaria sp. Pada Media Mengandung Logam Berat Kadmium (Cd)

2018 ◽  
Vol 21 (2) ◽  
pp. 129 ◽  
Author(s):  
Bambang Yulianto ◽  
Rini Pramesti ◽  
Rozi Hamdani ◽  
Sunaryo Sunaryo ◽  
Adi Santoso
Keyword(s):  
Heavy Metals ◽  
Exposure Time ◽  
Metal Contamination ◽  
Heavy Metal Contamination ◽  
Specific Growth ◽  
Laboratory Method ◽  
Control Treatment ◽  
Potential Toxicity ◽  
Experimental Laboratory ◽  
Lower Biomass

Bioabsorption competence and the growth of the seaweed Gracilaria sp. in seawater containing (Cd) heavy metal  Contamination of coastal and marine waters by heavy metals in significant concentrations will threaten the lives of inhabitant. One of the dangerous heavy metals due to its potential toxicity is cadmium (Cd). The purpose of this study was to determine: 1) bioabsorption competence of Gracilaria sp. against Cd in seawater, 2) the effect of exposure time on Cd content absorbed by Gracilaria sp., and 3) growth of Gracilaria sp. in Cd-contaminated media with different concentrations. This study used an experimental-laboratory method, by exposing Gracilaria sp. to three different concentrations and one control treatment (A: Control; B: 0.1 mg/L; C: 1 mg/L; and D: 10 mg/L) for 4 weeks. Observation of bioabsorption competence and growth of Gracilaria sp. was conducted every week. The result showed that Gracilaria sp. was capable of absorbing Cd dissolved in seawater. The concentrations of Cd absorbed by Gracilaria sp., in treatment B were 1.81 mg/kg (first week), 2.33 mg/kg (second week), 4.51 mg/kg (3rd week), and 1.47 mg/kg (4th week); in treatment C were 8.07 mg/kg (first week), 11.67 mg/kg (second week), 9.86 mg/kg (3rd week), and 8.67 mg/kg (4th week); and in treatment D were 52.59 mg/kg (first week), 56.66 mg/kg (second week), 78.01 mg/kg (3rd week), and 87.67 mg/kg (4th week). It is concluded that Gracilaria sp is capable of absorbing cadmium dissolved in seawater. However, the absolute and specific growth rate of Gracilaria sp. decreased and showing lower biomass due to exposure to Cd-contaminated media, making Gracilaria sp. not an ideal species to be used as a Cd-metal hyperaccumulator. Kontaminasi perairan pesisir dan laut oleh logam berat dalam konsentrasi yang signifikan akan mengancam bagi kehidupan biota yang ada di dalamnya. Salah satu logam berat yang berbahaya karena sifat toksisitasnya adalah Kadmium (Cd). Tujuan dari penelitian ini untuk mengetahui: 1) kemampuan bioabsorpsi  rumput laut Gracilaria sp. terhadap logam berat Cd dalam media air laut dengan konsentrasi yang berbeda, 2) mengetahui pengaruh perbedaan waktu pendedahan (exposure time) terhadap kandungan logam Cd terabsorpsi oleh Gracilaria sp., dan 3) mengetahui pertumbuhan Gracilaria sp. pada media terkontaminasi logam berat Cd dengan konsentrasi yang berbeda. Penelitian menggunakan metode eksperimental laboratoris, dengan melakukan pemaparan rumput laut Gracilaria sp. pada tiga perlakuan konsentrasi yang berbeda dan satu perlakuan kontrol (A: Kontrol; B: 0,1 mg/L; C; 1 mg/L; dan D 10 mg/L) selama 4 minggu masa pemeliharaan. Pengamatan kemampuan bioabsorpsi dan pertumbuhan Gracilaria sp. dilakukan setiap minggu. Hasil penelitian kemampuan bioabsorpsi  menunjukkan bahwa Gracilaria sp. mampu menyerap logam  Cd yang terlarut dalam air laut. Konsentrasi logam berat Cd yang diserap Gracilaria sp. pada perlakuan B = 1,81 mg/kg (minggu ke-1); 2,33 mg/kg (minggu ke-2); 4,51 mg/kg (minggu ke-3); 1,47 mg/kg (minggu ke-4). Perlakuan C = 8,07 mg/kg (minggu ke-1); 11,67 mg/kg (minggu ke-2); 9,86 mg/kg (minggu ke-3); 8,67 mg/kg (minggu ke-4). Perlakuan D = 52,59 mg/kg (minggu ke-1); 56,66 mg/kg (minggu ke-2); 78,01 mg/kg (minggu ke-3); 87,67 mg/kg (minggu ke-4). Pertumbuhan Gracilaria sp. (pertumbuhan mutlak dan laju pertumbuhan spesifik) mengalami penurunan berat biomassa akibat pemaparan pada media mengandung logam Cd, sehingga menjadikan spesies Gracilaria sp. bukan sebagai spesies hiperakumulator logam Cd.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

Productivity of corn hybrids of different fao groups depending on microfertilizers and growth stimulants under irrigation in the south of Ukraine

2016 ◽  
Vol 3 (1) ◽  
pp. 55-60
Author(s):  
Yu. Lavrynenko ◽  
R. Vozhegova ◽  
O. Hozh
Keyword(s):  
Grain Quality ◽  
Laboratory Method ◽  
The South ◽  
Corn Hybrids ◽  
Early Maturity ◽  
Effi Ciency ◽  
Grain Moisture ◽  
Grain Productivity ◽  
The Impact

The purpose of the research is to identify effi cient microfertilizers and growth stimulants considering biologi- cal features of new corn hybrids of different FAO groups under irrigation conditions in the South of Ukraine and trace their impact on grain productivity of the plants. The methods of the research are the fi eld method – to study the interaction of the research object with experimental factors of the natural environment, to register the yield and evaluate the biometrical indices; the laboratory method – to measure soil moisture, grain moisture content and grain quality indices; the statistical method – to evaluate the reliability of the obtained results; the calculation methods – for economic and energetic assessment of the growing techniques used. The results of the research. The paper defi nes the impact of microfertilizers and growth stimulants on the yield and grain quality of the corn hybrids of different maturity groups and on the economic effi ciency of growing them. The conclusions of the research. Under irrigation conditions of the Southern Steppe of Ukraine it is recommended that the following hybrids should be grown in dark-chestnut soils: early maturity DN Pyvykha, medium-early Skadovskyi, medium maturity Kakhovskyi and medium-late Arabat, using the growth stimulants – treating the seeds with Sezam-Nano and fertilizing with Grainactive at the stage of 7–8 leaves.

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