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In scientific and technical writing the choice of verb tenses is quite limited. The most
commonly used tenses are
ƒ the simple present
ƒ the simple past
ƒ the present perfect.
How is the present tense used?
It is used to state facts that are generally valid from the point of view of the writer. Therefore,
use it in the following situations:

• when writing about your topic or background
  Lasers are devices which amplify light and produce beams of light which are very intense, directional,
  and pure in colour.
  Little is known about HPS systems , which are the subject of the following chapter.


• when explaining your purpose
  Here we investigate the properties of the above mentioned metals.
  The perturbation method we develop here applies to any crack geometry as long as the crack-face
  weight function solutions are known for the corresponding reference crack.


• when presenting results, if the findings are general facts
  In cases when the eigenvalue of interest is well separated from the others, K2 tends to increase the
  natural frequencies of the forward and backward waves but decrease the natural frequency of the
  reflected wave, just opposite to the effect of M2.


• when making general statements, e.g. in conclusions
  This observation indicates an obvious inconsistency that is avoided by the introduction of generalised
  principles.
  The author believes that one particular application, where the results can be useful, is the modelling
  of contact problems involving anisotropic materials.
  There are differences in the way the passive and the active forms are used:


• the present simple passive is used when describing a process or procedure (see
  Section 4.4 on the Passive Voice)


• the present simple active is preferred in physical descriptions, such as describing a
  piece of apparatus or equipment
  The plotter represents another important output device. The plotter makes hard copy of the product
  represented by digital information in the computer. Most CAD systems use a pen plotter.
  How is the past tense used?
  You use this when referring to specific tasks carried out, such as taking measurements,
  conducting experiments, describing methods actually used, or presenting your results and
  conclusions from the particular piece of work.
  62Grammar


• The past simple passive is mainly used when we report a particular procedure related
  to only one particular occasion in the past. (See Section 5.4 on Passive Voice)
  In Fig.4 the uniaxial curve was calculated using Eq. /51/, the deviatoric stress-strain curve was
  calculated using Eq./20/, and the hydrostatic stress-strain curve was calculated using Eq./52/.
  Experimental results were obtained by the use of surface wave transducers, which were placed on
  two perpendicularly intersecting faces of a polished aluminium block.


• The past tense is also used in the introduction to give historical background or
  development in the field of interest:
  Technologists and craftspeople of early civilisations built huge objects. Algebra and trigonometry were
  well understood and applied during those early years. Construction of the pyramids of Egypt and of
  Central and South America required experience and the labour of many people.
  I started my research at the beginning of this term.


• The past tense is commonly used in acknowledgements:
  The work, which led to this paper, was sponsored by the Natural Sciences and Engineering Research
  Council of Canada. This financial support is greatly appreciated.
  How is the present perfect used?


• It is commonly used in the introduction, particularly when you want to recapitulate
  the state of the art and show what work has been done and is still in progress. (See
  also Section 4.4 on the Passive Voice)
  Recent progress in materials science, the development of new sophisticated application-designed
  materials, and especially the unique qualities of composite materials, have given a renewed interest in
  the problems arising when several different material phases interact with each other.
  This chapter has provided you with career information that will help you decide whether or not to
  pursue a technical degree.
  What other tenses are used in scientific and technical writing?
  ƒ Present Continuous


• This can be found in reports on studies or research, mainly in the introduction. You
  use it when you want to stress that something is currently in progress or is only
  temporary.
  I am studying for a Ph.D. at Brno University of Technology.
  I am doing research into the problems of industrial waste.
  ƒ Past Perfect


• This is not commonly used in technical/scientific writing. However, it is the tense you
  would use if you want to indicate that one action preceded another action in the past.
  The epoxy, a modified bisphenol that had been mixed with an amido-amine hardener, was cast
  directly to the glass and cured at room temperature for at least a week.
  ƒ Future tense with will


• This is not so frequently used as the present and past tenses. Use it when explaining
  how you intend to present information, give examples or describe visuals. It also
  indicates future events or parts of your work that come later.
  63Grammar
  The following examples of converting English units will employ a technique known as multiplying by
  the unit ratio.
  We will consider here the operating environment.
  Item number I 'concrete' will be examined to clarify further the spreadsheet results.


• NOTE: Do not use the future tense in the subordinate clause in time or conditional
  sentences (with When … or If …, etc.)
  The real value of the spreadsheet will be seen when the next survey is conducted.
  After the collected information is entered into the computer, the new minimum and maximum costs
  will be automatically calculated.
  ƒ Conditional


• In technical and scientific writing, the conditional is mainly used in
  acknowledgements:
  The authors would like to acknowledge the support of the National Science Foundation through Grant
  number CDR 589712.
  Both professionally and personally, I should like to thank just some of the many people who have
  influenced this book.
  Points to check in your writing
  ƒ Within one paragraph, it is not usual to shift tenses unless there is a good reason to do so.
  The example below is the final paragraph of the introduction to a scientific paper. This
  paragraph


• summarises the purpose of the paper (in the past tense),


• states the current state of development in the area of interest (present perfect),


• indicates the aim of the paper (future tense), and


• reports the results performed by the authors (past tense).
  The purpose of the work presented here was to examine interfacial crack initiation over a wide range
  of mode mixes. The analysis and development of a suitable specimen and biaxial device have already
  been described. This paper will present the results and analysis of a series of experiments that were
  conducted with various combinations of tensile and positive or negative shear loads.
  ƒ When all verbs describe a sequence of actions or states, their tenses should be the same.
  This is often the case in describing an experiment.
  In the petroleum industry, one of the most widely used methods for enhancing production is the
  hydraulic fracturing process. The method involves packing off a section of a borehole in the “pay
  zone” and hydraulically pressurizing it until the formation fractures. The fracture is then propagated by
  keeping the borehole pressurized, typically by controlling the flow rate at the surface.
  ƒ variation between passive and active constructions is strongly recommended to keep the
  reader interested. (See Section 4.4 on the Passive Voice.)
  ƒ check your use of tenses in if clauses (see above)
  If the relative width of the tube is greater than 20, then the difference is /will be hardly affected by h.
  If the experiments were carried out by introducing edge conditions nearer to true simple supports than
  those imposed within tubes, the buckling loads could be higher than those obtained in tube
  experiments.
  64Grammar
  5.7 Word Order
  English is generally considered to be a language with a relatively fixed word order. In
  practice, this means that the positions of the subject S, the main verb V, and the object O are
  fixed in relation to each other. In normal statements, which form the bulk of technical and
  scientific writing, these items occur regularly in the order S-V-O.
  subject (S) verb (V) object (O)
  Many flexible objects and structures undergo large deformations.
  The problem in technical and scientific writing is that parts of a sentence, particularly the
  subject, can become too long and complex, and therefore the basic structure may not be
  always clear.
  The subject
  ƒ With longer subjects, it is very important to keep together the words that form the subject.
  The formulas for the uniaxial and hydrostatic stress-strain relationship given by Eqs. 49 and 50 are
  based on a model consisting of an infinite number of elastoplastic elements connected in parallel.
  ƒ However, you should avoid overlong subjects. It is difficult for the reader to process a
  long structure without losing the sense of the sentence as a whole. In such cases, it is
  much better to re-formulate the sentence. One way of doing this is to turn the verb into a
  noun, which then forms the subject of the sentence. This new subject is short and the new
  verb, which is often in the passive, is introduced as early as possible and is not left
  dangling at the end of the sentence.
  overlong subject In this article, the results of the studies into the role of different parts of the
  society in applying several types of economic incentives for waste
  management are summarised.
  improved sentence In this article, a summary is given of the results of studies into the role of
  different parts of society in applying various types of economic incentives for
  waste management.
  The verb
  ƒ The verb should be positioned as close to the subject as possible. The mistake of placing
  the verb at the end of the sentence after an over-long subject has been mentioned above.
  No damage was observed in the specimen due to the uniaxial compressive stress.
  ƒ The regular pattern S-V is inverted when you want to signal the existence or presence of
  something new by using there is / are / was / were, etc.
  There has been relatively little examination of the effect of mode on subcritical crack growth.
  ƒ Similarly, the subject - verb word order is changed when you start a sentence with It is /
  was … that … to show emphasis. See Section 3.5 Emphasising.
  The objects in a sentence
  ƒ The direct object comes as close as possible to the verb, and normally before
  prepositional or adverbial phrases.
  We have sent a new type of laser to the research, development, and testing office in Seattle.
  65Grammar
  The position of adverbial phrases
  The most flexible elements in a sentence are the various kinds of adverbs and adverbial
  phrases. They are the most movable as they can occur at the start, in the middle or at the end.
  With the star-shaped flyer plate, cracks are observed to have formed at the middle of each free edge
  of the sample.
  Various numerical methods were recently developed for engineering problems.
  ƒ The first element in the sentence attracts most attention. It is usually the subject but if
  another sentence element is to be emphasised, it comes first. (See Section 3.5
  Emphasising). A comma is often used to separate this structure from the rest of the
  sentence (See Section 4.5 Punctuation).
  In industry, large databases are maintained on manufacturing processes.
  When purchasing a monitor, the number, or density, of pixels is a good guideline.
  ƒ The position of the time reference at the beginning of the sentence does not necessarily
  mean that this structure is emphasized. The time reference can be used as a convenient
  introduction in order to avoid breaking the flow with too many interruptions.
  This year again, our research group will introduce new methods developed within the project CZ

ƒ When the place reference comes first, the use of the passive can be used.
In a Dirichlet-type of problem, T is specified; T M and F M are computed from relative sizes and
positions of the holes.
ƒ It is best to avoid using more than one adverbial phrase at the beginning of a sentence.
With respect to the base parametrization, three model types are included in this study.
How to position also
ƒ Generally, also is placed after the auxiliary verb (if there is one), but before the stem verb
Finite element schemes also exist for determining the weight functions numerically.
Systematic errors may be caused by the environment, the instrument, or the experimenter.
Systematic errors may also be identified and eliminated during the laboratory.
ƒ If also functions as a link word for the sentence as a whole, then it is best to place it
AFTER the subject of the sentence rather than as the first word.
These procedures provide the ability to visualize externally applied forces. They also require the
differentiation of constraint functions, which are not given any geometrical significance.
Points to check in your own writing
ƒ Have I avoided long noun phrases, with verbs left dangling at the end of a long sentence?
Can I rewrite the sentence to make it more readable?
ƒ Have I used a variety of adverbial phrases at the start of sentences, to give the right
emphasis to my ideas?
ƒ Most importantly, have I used the best word order to convey my points clearly to the
reader?
66Words
Chapter 6 WORDS
6.1 Abbreviations
In scientific writing, there are a number of abbreviations in use which originate from Latin or
Greek. In general it is not a good idea to use too many of these within the body of your
writing, but they can be used occasionally when needed, and they are often necessary in your
references and bibliography.
Below is a selection of common abbreviations and their English equivalents.
abbreviation Latin words in full meaning
AD anno Domini since the birth of Christ
a.m. ante meridiem in the morning
BC before Christ
c. or ca. circa approximately, about (for dates)
cf. confer compare
e.g. exempli gratia for example, for instance
et al. et alii / et alia and others
etc. et cetera and so on, and the rest
et seq. et sequens and the following pages
ibid. ibidem in the same place / book
i.e. id est that is, in other words
inter alia among other things
loc.cit. loco citato in the place mentioned
NB nota bene note well (for an important point)
op. cit. opere citato in the work mentioned before
p.a. per annum a year, each year
per capita per head
p.m. post meridiem in the afternoon, evening
passim at various points in the book,
recurrent
q.v. quod vide see in another place in the same
book (for a cross-reference)
v. / vs. versus against
viz. videlicet namely (naming something you
have just referred to
67Words
6.2 Prefixes
A common way of making new words in English is by adding standard combinations of
letters to existing words, either at the beginning (prefixes) or at the end (suffixes). By noting
these carefully, you will find it easy to increase your vocabulary.
A prefix is a syllable, 2 syllables, or sometimes even a word, put at the beginning of a word
to change its meaning or to make another word. Prefixes are often used to give an adjective,
a verb or a noun a negative meaning, but there are also lots of other prefixes with specific
meanings.
Prefixes with the meaning not
The most common prefixes used to give a negative meaning to adjectives, and some verbs
and nouns, are as follows:
prefix use positive negative
un- used with many different words lucky
friendly
employed
unlucky
unfriendly
unemployed
im- used before words beginning with m or p possible
mature
impossible
immature
il- used before some words beginning with l literate
legible
illiterate
illegible
ir- used before some words beginning with r regular
responsible
irregular
irresponsible
in- used before a limited number of words correct
visible
incorrect
invisible
dis- used before some adjectives and a few verbs honest
like
dishonest
dislike
Unfortunately, there is no easy way of knowing which prefix any adjective will use to form
its negative. So when you learn a new adjective, note down whether it has an opposite
formed with a prefix and, if so, what it is.
ƒ The prefix in-. This does not always have a negative meaning – often it gives the idea of
inside or into,e.g. internal, insert, income .
ƒ Verb prefixes: un- and dis-. These prefixes have two meanings. They can have
a negative meaning ( as above), but they can also mean 'the opposite of an action' or 'to
reverse an action'. This meaning is used with certain verbs, e.g. to lock – to unlock, to
pack - to unpack , to appear – to disappear, to get dressed – to get undressed.
Other prefixes with specific meanings
Many other prefixes are used in English. Below is a list of prefixes which are useful in
helping you to understand unfamiliar words. Some of these words are used with a hyphen.
Check in a dictionary if you are not sure.
68Words
Prefix Meaning or Function Examples
a- ( an) not, not having atypical, anhydrous (not containing water)
aero- air aerospace
anti- against anti-toxin
auto- self, by itself autointoxication
bi- two bi-metallic
bio- life biology (science of life)
centi- 100 or 1/100 centimeter,Centigrade
co- together,with co-operation
contra- counter- against,opposite contra-rotating; counteract
de- taken away from dehydrated
deci- a tenth decimeter (tenth of a meter)
deka- ten dekameter (ten meters)
di- two, twice dioxide
hydro- (1) water
(2) hydrogen
hydrology
hydrocarbon
hyper- over, excessive hypertension
hypo- below,less than usual hypotension
infra- below, under infra-red (below the wavelenght of red)
inter- between interconnection
intra- inside intravenous
iso- equal isostatic
kilo- a thousand kilogram (me) (1000 gram (me)s)
macro- large, on a large scale macromolecule
mega (lo)- very large, a million megawatt (a million watts)
meta- change metamorphic
micro- small, on a small scale microorganism
milli- a thousandth milligram (me) (1000th of a gm)
mis- badly, mistakenly miscalculated
mono- one, single monochrome (of only one colour)
multi- many multilateral (with many sides)
neo- new neoclassical
non- not non-conductor
out- (1) more than
(2) beyond,outside
outwear (wear or last longer than)
outlying (beyond the main body)
over- (1) more than, excessive
(2) on top of, above
overproduction
overlie (to lie on top of)
para- similar to, irregular paratyphoid (disease similar to typhus but of different
origin)
pent (a)- five pentagon (5 –sided figure)
phot (o)- light photosynthesis
poly- many polymorphous
pre- before, previously prearranged
proto- first, original prototype
quadri- four quadrivalent (having a valency of 4)
re- (1) again, back
(2) together, mutually
re-combine (to combine again after being separated)
react (to act on each other)
self- by itself self-regulating
semi- half,imperfect semi-conductor
sub- under,below,less than sub-atomic
super- (supra)- above,beyond,more than supersonic
syn- (m)- with, together synthesis
tetra- four tetrad (element having valency of 4)
therm- heat thermodynamics
tri- three triangle
ultra- beyond, more than usual ultraviolet
under- (1) less than, insufficient
(2) below, lower than
underpressure
undersea
uni- one unicellular
69Words
6.3 Suffixes
A suffix is a syllable or syllables put at the end of a word to change its word-class and / or its
meaning. Suffixes can briefly be divided into
noun suffixes complication
adjective suffixes flexible
verb suffixes minimise
Noun suffixes
ƒ Verb + suffix. Many nouns are formed by adding a suffix to a verb. The most common
suffixes of this type are as follows:
Verb Suffix Noun
enlarge -ment enlargement
elect -(t)ion election
inform -ation information
write -ing writing
dance, manage -er dancer, manager
direct -or director

• Note: sometimes there is a spelling change. The most common is the omission of the
  final e before the suffix - ion or – ation: translate / translation.
  ƒ Noun + suffix. -ist is a common suffix added to existing nouns to describe people and
  their jobs : ecologist, journalist, artist.
  ƒ Adjective + suffix. Nouns are also formed by adding a suffix to an adjective. Two
  suffixes often added to adjectives to form nouns are -ness and -ity.
  adjective suffix noun
  rich -ness richness
  stupid -ity stupidity
  Adjective suffixes
  ƒ Noun or verb + suffix. Adjectives can be formed from nouns or verbs by adding these
  suffixes:
  noun or verb suffix adjective
  fame -ous famous
  industry -al industrial
  sun -y sunny
  create -ive creative
  ƒ Suffixes can change word class, e.g . from verb to noun, or noun to adjective, but they can
  also change meaning. The suffixes - able and –ible quite often have the meaning of can
  be done, e.g. something that is comprehensible can be comprehended.
  ƒ Words ending in –ible often add the prefix in- for their negative forms: incomprehensible
  ƒ The suffix –ful often means 'full of': colourful = full of colours.
  ƒ The suffix – less means 'without': odourless = without odour
  70Words
  Here is a list of common suffixes in alphabetical order, their meaning or function and some
  examples
  Suffix Meaning or Function Example

• able (1) forms adjective from verb
  (2) with verb means “can be done”
  reliable
  drinkable, countable


• age (1) forms noun from verb
  (2) forms abstract noun with idea of aggregat
  storage
  tonnage (total number of tons)


• al (1) forms adjective from noun
  (2) forms noun of action from verb
  physical, legal
  trial (action of trying or testing),
  arrival


• an (see –ian)


• ant (-ent) forms noun and adjective from verb resistant, determinant


• ate (1) in the shape of, like
  (2) possessing
  dentate (in the shape of a tooth)
  nucleate (having a nucleus)


• ation forms noun from verb information, organisation


• cy forms noun from adjective accuracy


• ent (see - ant)


• er forms noun from verb
  (1) person who does an activity
  (2) used for things which do a particular job
  computer
  writer
  bottle-opener


• ful forms adjective from verb forgetful, hopeful


• hood forms abstract nouns especially family
  terms
  childhood, motherhood


• ian (1) forms personal noun from sciences
  (2) forms personal noun from countries
  mathematician
  Australian


• ible see – able


• ify forms verb from noun or adjective intensify


• ine forms adjective from noun saline (having the property of salt)


• ing forms noun from verb jogging, spelling


• ion (see –tion)


• ise (GB) / ize (US) forms verb from adjective modernise, synthesize


• ish a bit, resembling yellowish (a bit yellow)


• ism activity or ideology journalism, Buddhism,


• ist forms personal noun from sciences geologist


• ity forms abstract noun from adjective uniformity


• ive forms adjective from verb selective


• less forms adjective from noun colourless (without colour)


• logy study, science biology (life science)


• ly forms adverb from adjective quickly (in a quick manner)


• ment forms noun from verb excitement, replacement


• meter instrument which measures manometer


• ness forms abstract noun from adjective completeness (quality of being
  complete)


• oid like, tending towards anthropoid (like a man)


• or see –er


• ous forms adjectives delicious


• scope instrument for seeing telescope


• sion (see - tion)


• ship forms abstract nouns, especially status friendship, membership


• sis process, state (in medicine a diseased
  state)
  symbiosis


• tion ( - sion) forms noun from verb combinationTo summarize this book


• ty (see - ity)
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