- 6 SPECIFICATIONS Maximum User Weight: 150 kg (330 lbs.) Machine Weight without Dumbbells: 48.1 kg (106 lbs.) Weight of Dumbbells (supplied with IC4): 2.7 kg (6 lbs.) Total Surface Area (footprint) of equipment: 6667 cm2 (1033.3 in2.
- 7) A 6.2 kg object is pulled along a horizontal surface by a force of 22.0 N. If 2its acceleration is 1.1 m/s, what is the coefficient of friction between the two surfaces? 8) A 1250 kg car traveling at 60.0 km/h comes to a sudden stop in 35 m.
What does LD50 mean?
An asteroid of mass 7.2×1018 kg is on a collision course with Earth. Our planet will be saved if the asteroid is given an acceleration of merely 1.5×10−5 m/s 2. Find the required force. 2.An airplane is flying at a velocity of 74 m/s eastward relative to the air. Due to a high-pressure region to the north, the velocity of the air.
LD stands for 'Lethal Dose'. LD50 is the amount of a material, given all at once, which causes the death of 50% (one half) of a group of test animals. The LD50 is one way to measure the short-term poisoning potential (acute toxicity) of a material.
Toxicologists can use many kinds of animals but most often testing is done with rats and mice. It is usually expressed as the amount of chemical administered (e.g., milligrams) per 100 grams (for smaller animals) or per kilogram (for bigger test subjects) of the body weight of the test animal. The LD50 can be found for any route of entry or administration but dermal (applied to the skin) and oral (given by mouth) administration methods are the most common.
What does LC50 mean?
LC stands for 'Lethal Concentration'. LC values usually refer to the concentration of a chemical in air but in environmental studies it can also mean the concentration of a chemical in water.
According to the (Organisation for Economic Cooperation and Development) (OECD) Guidelines for the Testing of Chemicals, a traditional experiment involves groups of animals exposed to a concentration (or series of concentrations) for a set period of time (usually 4 hours). The animals are clinically observed for up to 14 days.
The concentrations of the chemical in air that kills 50% of the test animals during the observation period is the LC50 value. Other durations of exposure (versus the traditional 4 hours) may apply depending on specific laws.
Why study LD50's?
Chemicals can have a wide range of effects on our health. Depending on how the chemical will be used, many kinds of toxicity tests may be required.
Since different chemicals cause different toxic effects, comparing the toxicity of one with another is hard. We could measure the amount of a chemical that causes kidney damage, for example, but not all chemicals will damage the kidney. We could say that nerve damage is observed when 10 grams of chemical A is administered, and kidney damage is observed when 10 grams of chemical B is administered. However, this information does not tell us if A or B is more toxic because we do not know which damage is more critical or harmful.
Therefore, to compare the toxic potency or intensity of different chemicals, researchers must measure the same effect. One way is to carry out lethality testing (the LD50 tests) by measuring how much of a chemical is required to cause death. This type of test is also referred to as a 'quantal' test because it is measures an effect that 'occurs' or 'does not occur'.
Who invented the idea of an LD50?
In 1927, J.W. Trevan attempted to find a way to estimate the relative poisoning potency of drugs and medicines used at that time. He developed the LD50 test because the use of death as a 'target' allows for comparisons between chemicals that poison the body in very different ways. Since Trevan's early work, other scientists have developed different approaches for more direct, faster methods of determining the LD50.
What are some other toxicity dose terms that are used?
LD01 Lethal dose for 1% of the animal test population
LD100 Lethal dose for 100% of the animal test population
LDLO The lowest dose causing lethality
Understand 5 1 1018 Kg =
TDLO The lowest dose causing a toxic effect
Why are LD50 and LC50 values a measure of acute toxicity?
Acute toxicity is the ability of a chemical to cause ill effects relatively soon after one oral administration or a 4-hour exposure to a chemical in air. 'Relatively soon' is usually defined as a period of minutes, hours (up to 24) or days (up to about 2 weeks) but rarely longer.
How are LD/LC50 tests done?
In nearly all cases, LD50 tests are performed using a pure form of the chemical. Mixtures are rarely studied.
The chemical may be given to the animals by mouth (oral); by applying on the skin (dermal); by injection at sites such as the blood veins (i.v.- intravenous), muscles (i.m. - intramuscular) or into the abdominal cavity (i.p. - intraperitoneal).
The LD50 value obtained at the end of the experiment is identified as the LD50 (oral), LD50 (skin), LD50 (i.v.), etc., as appropriate. Researchers can do the test with any animal species but they use rats or mice most often. Other species include dogs, hamsters, cats, guinea-pigs, rabbits, and monkeys. In each case, the LD50 value is expressed as the weight of chemical administered per kilogram body weight of the animal and it states the test animal used and route of exposure or administration; e.g., LD50 (oral, rat) - 5 mg/kg, LD50 (skin, rabbit) - 5 g/kg. So, the example 'LD50 (oral, rat) 5 mg/kg' means that 5 milligrams of that chemical for every 1 kilogram body weight of the rat, when administered in one dose by mouth, causes the death of 50% of the test group.
If the lethal effects from breathing a compound are to be tested, the chemical (usually a gas or vapour) is first mixed in a known concentration in a special air chamber where the test animals will be placed. This concentration is usually quoted as parts per million (ppm) or milligrams per cubic metre (mg/m3). In these experiments, the concentration that kills 50% of the animals is called an LC50 (Lethal Concentration 50) rather than an LD50. When an LC50 value is reported, it should also state the kind of test animal studied and the duration of the exposure, e.g., LC50 (rat) - 1000 ppm/ 4 hr or LC50 (mouse) - 5mg/m3/ 2hr.
The chemical may be given to the animals by mouth (oral); by applying on the skin (dermal); by injection at sites such as the blood veins (i.v.- intravenous), muscles (i.m. - intramuscular) or into the abdominal cavity (i.p. - intraperitoneal).
The LD50 value obtained at the end of the experiment is identified as the LD50 (oral), LD50 (skin), LD50 (i.v.), etc., as appropriate. Researchers can do the test with any animal species but they use rats or mice most often. Other species include dogs, hamsters, cats, guinea-pigs, rabbits, and monkeys. In each case, the LD50 value is expressed as the weight of chemical administered per kilogram body weight of the animal and it states the test animal used and route of exposure or administration; e.g., LD50 (oral, rat) - 5 mg/kg, LD50 (skin, rabbit) - 5 g/kg. So, the example 'LD50 (oral, rat) 5 mg/kg' means that 5 milligrams of that chemical for every 1 kilogram body weight of the rat, when administered in one dose by mouth, causes the death of 50% of the test group.
If the lethal effects from breathing a compound are to be tested, the chemical (usually a gas or vapour) is first mixed in a known concentration in a special air chamber where the test animals will be placed. This concentration is usually quoted as parts per million (ppm) or milligrams per cubic metre (mg/m3). In these experiments, the concentration that kills 50% of the animals is called an LC50 (Lethal Concentration 50) rather than an LD50. When an LC50 value is reported, it should also state the kind of test animal studied and the duration of the exposure, e.g., LC50 (rat) - 1000 ppm/ 4 hr or LC50 (mouse) - 5mg/m3/ 2hr.
Which LD50 information is the most important for occupational health and safety purposes?
Inhalation and skin absorption are the most common routes by which workplace chemicals enter the body. Thus, the most relevant from the occupational exposure viewpoint are the inhalation (LC50) and skin application tests (LD50-skin). Despite this fact, the most frequently performed lethality study is the oral LD50. This difference occurs because giving chemicals to animals by mouth is much easier and less expensive than other techniques. However, the results of oral studies are important for drug studies, food poisonings, and accidental domestic poisonings. Oral occupational poisonings might occur by contamination of food or cigarettes from unwashed hands, and by accidental swallowing.
How do I compare one LD50 value to another and what does it mean to humans?
In general, the smaller the LD50 value, the more toxic the chemical is. The opposite is also true: the larger the LD50 value, the lower the toxicity.
The LD50 gives a measure of the immediate or acute toxicity of a chemical in the strain, sex, and age group of a particular animal species being tested. Changing any of these variables (e.g., type animal or age) could result in finding a different LD50 value. The LD50 test was neither designed nor intended to give information on long-term exposure effects of a chemical.
Once you have an LD50 value, it can be compared to other values by using a toxicity scale. Confusion sometimes occurs because several different toxicity scales are in use. The two most common scales used are the 'Hodge and Sterner Scale' and the 'Gosselin, Smith and Hodge Scale'. These tables differ in both the numerical rating given to each class and the terms used to describe each class. For example, a chemical with an oral LD50 value of 2 mg/kg, would be rated as '1' and 'highly toxic' according to the Hodge and Sterner Scale (see Table 1) but rated as '6' and 'super toxic' according to the Gosselin, Smith and Hodge Scale (see Table 2). It is important to reference the scale you used when classifying a compound.
It is also important to know that the actual LD50 value may be different for a given chemical depending on the route of exposure (e.g., oral, dermal, inhalation). For example, some LD50s for dichlorvos, an insecticide commonly used in household pesticide strips, are listed below:
- Oral LD50 (rat): 56 mg/kg
- Dermal LD50 (rat): 75 mg/kg
- Intraperitoneal LD50: (rat) 15 mg/kg
- Inhalation LC50 (rat): 1.7 ppm (15 mg/m3); 4-hour exposure
- Oral LD50 (rabbit) 10 mg/kg
- Oral LD50 (pigeon:): 23.7 mg/kg
- Oral LD50 (rat): 56 mg/kg
- Oral (mouse): 61 mg/kg
- Oral (dog): 100 mg/kg
- Oral (pig): 157 mg/kg
Differences in the LD50 toxicity ratings reflect the different routes of exposure. The toxicity rating can be different for different animals. The data above show that dichlorvos is much less toxic by ingestion in pigs or dogs than in rats. Using Table 1, dichlorvos is moderately toxic when swallowed (oral LD50) and extremely toxic when breathed (inhalation LC50) in the rat. Using Table 2, dichlorvos is considered very toxic when swallowed (oral LD50) by a rat.
| Table 1: Toxicity Classes: Hodge and Sterner Scale | |||||
|---|---|---|---|---|---|
| Routes of Administration | |||||
| Oral LD50 | Inhalation LC50 | Dermal LD50 | |||
| Toxicity Rating | Commonly Used Term | (single dose to rats) mg/kg | (exposure of rats for 4 hours) ppm | (single application to skin of rabbits) mg/kg | Probable Lethal Dose for Man |
| 1 | Extremely Toxic | 1 or less | 10 or less | 5 or less | 1 grain (a taste, a drop) |
| 2 | Highly Toxic | 1-50 | 10-100 | 5-43 | 4 ml (1 tsp) |
| 3 | Moderately Toxic | 50-500 | 100-1000 | 44-340 | 30 ml (1 fl. oz.) |
| 4 | Slightly Toxic | 500-5000 | 1000-10,000 | 350-2810 | 600 ml (1 pint) |
| 5 | Practically Non-toxic | 5000-15,000 | 10,000-100,000 | 2820-22,590 | 1 litre (or 1 quart) |
| 6 | Relatively Harmless | 15,000 or more | 100,000 | 22,600 or more | 1 litre (or 1 quart) |
| Table 2: Toxicity Classes: Gosselin, Smith and Hodge | ||
|---|---|---|
| Probable Oral Lethal Dose (Human) | ||
| Toxicity Rating or Class | Dose | For 70-kg Person (150 lbs) |
| 6 Super Toxic | Less than 5 mg/kg | 1 grain (a taste – less than 7 drops) |
| 5 Extremely Toxic | 5-50 mg/kg | 4 ml (between 7 drops and 1 tsp) |
| 4 Very Toxic | 50-500 mg/kg | 30 ml (between 1 tsp and 1 fl ounce) |
| 3 Moderately Toxic | 0.5-5 g/kg | 30-600 ml (between 1 fl oz and 1 pint) |
| 2 Slightly Toxic | 5-15 g/kg | 600-1200 ml (between 1 pint to 1 quart) |
| 1 Practically Non-Toxic | Above 15 g/kg | More than 1200 ml (more than 1 quart) |
Can animal LD50 data be applied to humans?
In general, if the immediate toxicity is similar in all of the different animals tested, the degree of immediate toxicity will probably be similar for humans. When the LD50 values are different for various animal species, one has to make approximations and assumptions when estimating the probable lethal dose for man. Tables 1 and 2 have a column for estimated lethal doses in man. Special calculations are used when translating animal LD50 values to possible lethal dose values for humans. Safety factors of 10,000 or 1000 are usually included in such calculations to allow for the variability between individuals and how they react to a chemical, and for the uncertainties of experiment test results.
Understand 5 1 1018 Kg Pounds
How should an LD50 value be used?
The LD50 can be used:
- As an aid in developing emergency procedures in case of a major spill or accident.
- To help develop guidelines for the use of appropriate safety clothing and equipment. For example, if the dermal LD50 value for a chemical is rated as extremely toxic, it is important to protect the skin with clothing, gloves (etc.) made of the right chemical-resistant material before handling. Alternatively, if a chemical has an inhalation LC50 value which indicates that it is relatively harmless, respiratory protective equipment may not be necessary (as long as the oxygen concentration in the air is in the normal range – around 18%).
- For the development of transportation regulations.
- As an aid in establishing occupational exposure limits.
- As a part of the information in Safety Data Sheets. Remember, the LD50 is only a ball park figure so that lethal toxicity can be compared. It says nothing about levels at which other acute toxic, but non-lethal, effects might occur.
The LD50 is only one source of toxicity information. For a more thorough picture of the immediate or acute toxicity of a chemical, additional information should be considered such as the lowest dose that causes a toxic effect (TDLO), the rate of recovery from a toxic effect, and the possibility that exposure to some mixtures may result in increasing the toxic effect of an individual chemical.
Where can I find LD50 and LC50 values?
The largest, single collection of LD50 and LC50 values is in the database Registry of Toxic Effects of Chemical Substances (RTECS) that is available by subscription on the Internet. Two other databases available from CCOHS, CHEMINFO and the Hazardous Substances Data Bank (HSDB), are in the CHEMpendium collection.
The Cub Cadet LT1018 is a 2WD lawn tractor from the LT1000 series. This tractor was manufactured by the Cub Cadet (a part of MTD) since 2004. The Cub Cadet LT 1018 is equipped with a 0.5 L single-cylinder gasoline engine and belt-driven hydrostatic transmission with infinite forward and reverse gears.
The Cub Cadet LT1018 lawn tractor used the Briggs & Stratton 31Q777 engine. It is a 0.5 L, 501 cm2, (30.6 cu·in) single-cylinder natural aspirated gasoline engine with 90.0 mm (3.54 in) of the cylinder bore and 78.0 mm (3.07 in) of the piston stroke. The compression ratio rating is 8.5:1. This engine produced 18.8 PS (13.8 kW; 18.5 HP) at 3,600 rpm of maximum output power and 35.0 N·m (3.6 kg·m, 25.8 ft·lb) at 2,400 rpm of peak torque.
The Cub Cadet LT1018 is equipped with manual steering, dry disc brakes, open operator station, and 11.4 liters (3 US gal.; 2.5 Imp. gal) fuel tank.
Following attachments are available for Cub Cadet LT 1018 lawn tractor:
- Mid-mount Cub Cadet mower deck with 2-blades
- Front-mount Cub Cadet 190-674 – 46 in (1,160 mm) blade
- Front-mount Cub Cadet 190-673 – 42 in (1,060 mm) two-stage snowblower
Cub Cadet LT1018 Specifications
| General Specifications | |
| Model | Cub Cadet LT1018 |
| Length | 1,720 mm (67.7 in) |
| Width | 1,140 mm (44.9 in) |
| Height | 1,090 mm (42.9 in) |
| Wheel base | 1,190 mm (46.9 in) |
| Weight | 227 kg (500 lbs) |
| Fuel tank capacity | 11.4 liters (3 US gal.; 2.5 Imp. gal) |
| Battery | 12V, CCA: 190A |
| Cabin type | Open operator station |
| Engine | |
| Engine model | Briggs & Stratton 31Q777 |
| Engine type | Four-stroke, air-cooled, inline |
| Cylinders | 1 |
| Fuel type | Gasoline |
| Displacement | 0.5 L, 501 cm2, (30.6 cu·in) |
| Bore and stroke | 90.0 mm X 78.0 mm (3.54 in X 3.07 in) |
| Compression ratio | 8.5:1 |
| Horsepower | 18.8 PS (13.8 kW; 18.5 HP) at 3,600 rpm |
| Torque | 35.0 N·m (3.6 kg·m, 25.8 ft·lb) at 2,400 rpm |
| Starter | Electric |
| Oil type | SAE 10W-30 |
| Oil capacity: | 1.4 L (1.48 US. qt, 1.23 Imp. qt.) |
| Spark plug | Champion RC12YC |
| Spark plug gap | 0.76 mm (0.030 in) |
| Transmission and chassis | |
| Chassis | 4×2 2WD |
| Steering type | Manual |
| Brakes | Dry disc |
| Transmission model | Hydro-Gear 311-0510 |
| Transmission type | Belt-driven hydrostatic |
| Gears | Infinite forward and reverse |
| Speed | Forward: 8.4 kmh (5.2 mph) Reverse: 3.7 (2.3 mph) |
| Tires | |
| Front tires | Lawn/turf: 15x6x6 |
| Rear tires | Lawn/turf: 20x9x8 |
| PTO (Power take-off shaft) | |
| Front PTO type | Independent with electric clutch |
| Front PTO spped | – rpm |
