CHAPTER IX CALCULATIONS AND FORMULAE
S. I. UNITS
The International System of Units is intended as a basis for worldwide standardiza- tion of measurement units. The system consists of base units, supplementary units and derived units. There are seven well-defined base units which by convention are dimension- ally independent. They are related to the variables of length, mass, time, temperature, electric current, luminous intensity and amount of substance. We shall be dealing here with the four former units.
Magnitude of Units
Different magnitudes of the S.I. Units are obtained by using decimal multiples or submultiples of base units. These are named by prefixes identifying the powers of ten to which the units are raised. Some of the more common ones are as follows:-
Thus, 12 millimeters - 12 mm
The prefixes are used to avoid large numbers, and non-significant digits and powers of ten notation. For example,
15,600 mm = 15.6 m 18.5 x 103 gm = 18.5 kg 0.000 m = 6 m m
Some of the prefixes are not in very common use e.g. hecto, deka, deci and centi (except cm) and should be avoided.
APPLICATION Rules for Writing
The writing of unit symbols and names is governed by international agreement and come under the following rules:-
1. Unit symbols should always be printed in Roman (upright) type;
2. Unit symbols are unaltered in the plural;
3. Unit symbols are not followed by a period except when used at the end of a
CONVERSION FACTORS
Conversion factors hesre are multiplying factors for converting measurements in one system to a corresponding measurement in the other system. In converting from one system to the next, accuracy should be preserved. Consequently, rules should be followed in applying them. However, the usual practice in the sugar industry is to do all multi- plications and divisions to at least three decimal places and then to round off to two places.
This is not accurate introducing apparently significant digits and greater accuracy than can be achieved and does not take into account the precision of the measuring devices.
This is acceptable within the industry. But there are definite rules of conversion as set out by the Bureau of Standards, which should be universally applied.
The following rules of conversion should be practised within the industry:
1. Conversions should first be ma de and then rounding off is done.
Neither the measured quantity nor the conversion factor should be rounded;
e.g. 23.6 ft. converted to metres = 23.6 ft. x 0.3048 m
= 7.193 28 m
= 7.19 m (rounded)
2. When the first digit to be discarded in rounding is less than 5, the last digit in the final number should not be changed;
e.g. 36.9348 rounded to 2 decimal places is 36.93 .
3. When the first digit to be discarded is greater than 5, or if it is a 5 followed by a number greater than 0, the last remaining digit should be increased by 1.
Thus 496.3251 = 496.33 (correct to 2 decimal places)
4. When the first digit discarded is exactly five followed by a zero, the last digit retained should be increased by 1 if it is an odd number, but remain unadjusted if it is an even number.
e.g. 53.9350 = 53.94 (Correct to 2 decimal places) 53.9250 = 53.92 (Correct to 2 decimal plgces).
SUGAR FACTORY OPERATIONS
The cost of conversion to the metric system would vary with different factories.
There are some equipment which may have to be replaced with ones made in metric dimensions. Scale heads may be replaced or recalibrated. In some cases measurements may have to be made in the British System and converted to the metric system. In any case metric units will be standard for all factories.
The following table lists the common variables in a sugar factory and field opera- tions with the usual British units, the conversion factors with the corresponding S.I.
unit.
CHAPTER XII
LABORATORY MANAGEMENT AND FIRST AID Care of Samplers & Containers
All sugar products are susceptible to rapid deterioration due to bacterial activity. All sample containers should therefore be thoroughly cleaned and frequently sterilised.
Sample jars should be washed with hot water after use and thoroughly dried. Metal containers should also be washed and steamed frequently.
Care of Optical Instruments
Optical instruments (polarimeters, refractometers, microscopes) are delicate and expensive. If treated properly they will last for a very long time; if not, they will deterior- ate very rapidly giving erroneous results.
These instruments should be set up in a position free from dampness and corrosive fumes, jarring and vibration. Where it is not practicable to set up an instrument away from the mill vibration it should be mounted on a suitable anti-vibration table.
The instrument should be examined and cleaned regularly, especially troughs and splash glasses of polarimeters and prisms of refractometers. Never use a sharp instrument to place material on prisms and always wipe with soft material.
Balances should be kept clean and handled with care. Weights should never be held with the fingers. Objects should never be weighed hot; but allowed to cool preferably in a desiccator. Instruments should be kept under a cover when not in continuous use.
Use and Care of pH Metre and Electrodes
All glass electrodes should be immersed in distilled water for at least twenty-four hours prior to use. When not in use, it should be stored in distilled water of buffer solu- tion, as repeated wetting and drying impairs the action of the glass membrane.
Check the electrodes at least once a day with standard buffer solution. The instrument should be protected from splashes of sample or water and kept dry.
Safety and First Aid
Accidents are caused - they do not happen. Persons are always directly or indirectly responsible for accidents.
The chemical laboratory is potentially a hazardous place, but if the necessary safety precautions are followed it can be as safe as any other place. The three areas of greatest danger are from:
a) Chemicals b) Fires and Explosion c) Glassware
REMEMBER ACCIDENTS ARE PAINFUL, EXPENSIVE AND CAN BE LETHAL.
AVOID THEM !!!
Spillage and Residuals
Mop up chemicals or water which may be spilled on the floor AT ONCE. A slip or stumble may be more serious in a chemical laboratory than elsewhere, as the person may not only be carrying a chemical but also a glass container.
Use of Pipette
When using a pipette be careful that no liquid is drawn into the mouth. Do not use a pipette to withdraw corrosive or poisonous liquids. Use an aspirator bulb, a burette or for less accurate work — a measuring cylinder.
Bottles and Other Containers
All containers should be clearly and correctly labelled. After consulting your supervi- sor, discard chemicals in containers which are unlabelled. This is a safety precaution:
NEVER INSERT ANYTHING INTO A REAGENT STOCK BOTTLE, POUR MATERIAL BACK INTO A STOCK BOTTLE OR EXCHANGE STOPPERS ON BOTTLES, OTHER- WISE CONTAMINATION MAY RESULT.
Always use a funnel to pour liquids from a larger mouthed container into a smaller one. Always replace the stopper immediately after pouring to avoid mix up and possible contamination. When pouring always hold the bottle in such a way that the label is upwards. This prevents damage to the label by the dripping back of liquid.
Solutions and Acids
Never add water to a concentrated acid, rather cautiously add acid to the water with constant stirring in small amounts at a time.
FIRST AID
First Aid is an immediate and temporary action given to a victim of an accident or sudden illness to prevent or reduce suffering and possible loss of life until proper medical aid is available.
General Hints
1. Always know what to look for; what to do and how to do it.
2. Prevent and/or reduce bleeding or further injury.
3. Check and maintain breathing and apply artificial respiration if necessary.
4. Avoid panic.
5. Develop confidence.
6. Summon help.
Burns and Scalds
Burns are the result of dry heat. Scalds are produced by a hot liquid or steam. Action of chemicals is referred to as a 'Chemical burn'.
Heat Burns and Scalds (Minor)
When the burn is confined to a part of the limb such as one hand, some lessening of pain may be achieved by immersing the injured area in cold water. Cover with dry sterile gauze or cloth.
(Serious) - If clothing is on fire, smother flames with a blanket or lab coat. Remove or cut away clothing over burned area, but do not attempt to pull away clothing which is stuck. Cover burned area with sterile or clean dressing and bandage or fasten securely.
In case of burns covering a large area of the body, it is sufficient to cover with a clean sheet or towel. If the patient is thirsty, he may be allowed to drink small amounts of clear fluid such as water. Seek medical aid promptly. Never treat large burns with tannic acid, oil or antiseptic ointment. These remedies greatly complicate the surgical treatment of the burned area and have only slight value in reducing pain.
Chemical Burns
Acid Burns — Wash copiously with quantities of tap water, then 1% sodium bicarbonate solution and again with water.
Alkali burns — Wash with copious quantities of tap water and then 1% acetic acid and more tap water.
Chemical in the Eye
To save sight first aid is vital. Flush eyes with large quantities of water. Seek medical aid.
Foreign Bodies in the Eye
NEVER rub the eye, blow the nose and tears will flow to help flush out particles. If this fails use eye bath or tap water to flush out particles. Glass in the eye is very serious and no first aid beyond covering the eye with sterile lint and bandaging firmly to prevent movement should be done. Seek medical aid immediately.
Wounds
Minor cuts - Remove dirt or glass, and wash under tap. Apply clean sterile dressing.
Severe Bleeding is stopped in the following manner:
a) If on the arm, leg, hand or foot and blood is scarlet and flowing intermittently, a torniquet is applied 4 ins. below the armpit, or 4 ins below the groin.
b) If the blood is dark and purplish, the tomiquet is applied below the wound. A piece of rubber tubing will make a good tomiquet.
CAUTION: Under no circumstances should the torniquet be held tight for longer than 15 minutes at a time. It is loosened and the blood allowed to flow for a few seconds, then re-tightened. The tomiquet is loosened but not removed as soon as the blood clots.
If bleeding is copious and the wound is in a position where a torniquet cannot be used a pad of sterile gauze soaked in acriflavine is placed in the wound and a bandage applied.
If the cut is slight and bleeding is copious, all foreign matter is removed and the cut is cleaned with acriflavine solution (1 in 1,000) and a dressing of this material applied.
POISONING (a) Strong Acids
Mouth or lips may be stained. Vomiting is not induced. Magnesium oxide, milk of magnesia or lime water is given immediately and is repeated at short intervals and the
mouth is washed with one of the above-mentioned materials. Carbonates are not to be given, but milk or white of egg. The patient is placed in a reclining position to combat collapse, and blankets etc. are applied.
(b) Alkalis
Mouth or lips may be stained. Vomiting is NOT induced. A 5% solution of acetic acid or vinegar is given until alkali appears to be neutralized. Milk or white of egg is given and the above efforts made to combat collapse.
(c) Copper Salts
If a fairly large amount is swallowed, give an emetic and after vomiting give white of egg or a suspension of charcoal in water. Avoid milk or oils.
(d) Lead Compounds
Vomiting is induced by stirring one teaspoonful of powdered mustard in suf- ficient water to make a creamy paste or warm salt water may be used, 4 gm. Sodium Thiosulphate in 450 ml water or 10% Magnesium Sulphate is administered. Combat collapse.
(e) Mercuric Chloride
One teaspoonful Sodium Thiosulphate in 500 ml water is given by mouth or a glass of milk with four tablespoonsful charcoal. Vomiting is induced and the treatment is repeated. Soothing drinks of milk and raw eggs are given.
(0 Silver Nitrate
Two tablespoonsful of table salt (Sodium Chloride) in 50 mls of water is given.
Vomiting is induced.
GAS POISONING (a) Corrosive gases
The patient is carried into fresh air, artificial respiration is applied, if necessary.
The patient, if conscious, is allowed to inhale an antidote (dilute acetic acid for ammonia, dilute ammonia for bromine, chlorine, hydrochloric acid or nitric acid fumes). Combat collapse.
(b) Carbon Monoxide, Hydrogen Sulphide and Nitrous fumes
The patient is removed to the fresh air, artificial respiration is applied and oxygen given. Combat collapse. After apparent recovery and restoration of breathing the patient is not allowed under any circumstances to walk or sit up until seen by a doctor.
SHOCK
Any injury may produce shock and may be serious enough to prove fatal. The symp- toms are paleness, moist skin and trembling. In case of minor injury, the patient must lie down and rest, a warm glucose drink may be given. Keep the patient lying down as long as possible. If vomiting develops keep the patient on his side and incline his head. Keep head lower than the rest of the body.
In cases of more serious injury, allow the patient to lie on his side. Try to get him cooler by loosening clothing.
If the patient is unconscious, do not give him fluids. As a general rule do not give the patient alcohol especially if abdominal injury is suspected.
Electric Shock
Firstly, switch off the current if possible or remove patient from the electrical contact by using a hooked dry stick or insulated material, e.g. dry towel or rubber tire or other rubber article.
Artificial respiration should then be given. The patient is kept warm.
FAINTING
When a person feels faint get his head down quickly. If the patient is sitting, lower his head between his knees or lay him down with his head lower than the feet. If unconscious, place in the prone or semiprone position. Loosen clothing at neck, chest and waist. See that there is plenty of fresh air. On recovery, which is usually rapid, gradually raise the patient and give sips of water or other beverage. If unconsciousness continues for a longer time, suspect some cause more serious than fainting and summon medical help.
ARTIFICIAL RESPIRATION
It has been shown conclusively that this is the only really efficient method.
When a casualty has stopped breathing it is more important to get oxygen (air) into the lungs than to try to discover exactly why he has stopped breathing, although the cause is often obvious from the surroundings, etc. e.g. electrocution, coal-gas poisoning. One indication that breathing has stopped is discoloration of the lips, nails, ears and cheeks.
The air breathed out contains more than enough oxygen to supply the need of the casualty.
(1) If possible, lie casualty on back with head a little higher than feet.
(2) Tilt the casualty's head back and lift the jaw. This should move the tongue away from the back of the throat, the most common cause of respiratory obstruction.
One of three things may now happen:
(i) Normal breathing may begin at once and consciousness may quickly return.
The casualty's colour becomes pink again. He should be watched carefully in case he stops breathing again.
(ii) Normal breathing may begin but consciousness not return. Place in the coma position and keep the airway clear (see Aftercare, page 69). The victim may have bumped his head.
(iii) Breathing may return but be noisy which means that the airway is not fully clear. All noisy breathing is obstructed breathing (but there is no noise when the airway is completely blocked). Try to clear the airway fully; there may be some fluid in the throat.
(3) If breathing does not restart clean the mouth and throat of any obvious block- age by fluid, vomit, weed or other obstruction.
(4) If after clearing the throat there is still no sign of breathing:
(ii) Take a deep breath;
(i) Check that the head is still tilted back;
(iii) Close his mouth and blow firmly but gently into his nose OR Pinch his nose and blow firmly but gendy into his mouth. As you do this the chest will rise.
(iv) Give four quick breaths and then continue with one breath every five seconds
— 12 times a minute.
(vi) If the chest does not rise and fall you are not making a proper seal over his nose or mouth, or the airway is still obstructed and needs to be cleared again.
(vii) If the casualty is a baby make a seal with your mouth over his mouth and nose and breathe into him gently with a puff of the cheeks. Repeat this about 20-25 times a minute. Do not blow violently into a baby's lungs.
(viii) If the airway is clear it will not be long before the "pink" colour replaces the
"blue" look. As consciousness returns the victim will start to breathe on his own; this is the time to stop resuscitation. Continue to hold his chin up and so keep his airway clear.
THE FIRST AID CABINET
The contents of a typical First Aid cabinet should be kept as simply as possible and grouped in a logical sequence. The labels should be clear and all ambiguity should be avoided.
The First Aid Cabinet Internal Medicines Aspirin Antacid ii) Dressings
Band Aid Sterile Gauze Bandages (gauze) Lint Strapping Cotton Wool
iii) Equipment Medicine droppers Scissors Tweezers Eye cup Forceps Torniquet
Cotton wool and cotton buds Thermometer (clinical) Safety pins Teaspoon and glass First Aid Manual iv) External Medicines
Mercurochrome Disinfectant Hydrogen Peroxide - 3%
Petroleum jelly Sodium bicarbonate — 5%
Alcohol - 95%
Eye lotion Olive oil Smelling salts Acriflavine
APPENDIX I