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APPENDIX C
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FIGURE C.2. Hypothetical study of chest injuries based on the viscous criterion.
SOURCE: Lobdell, T.E., C.K. Kroell, D.C. Schneider, W.E. Herring, and A.M. Nahum.
1972. "Impact Response of the Human Thorax," Proceedings of the Human Impact
Response Measurement and Simulation Symposium, General Motors Research Labora-
tories, October 2-3, Plenum Press, New York-London.
seen that there is a possible risk of chest injury from many of the rounds, based
on the predictions of the Lobdell model and the VC. An estimate of the toler-
ance of the heart to ventricular fibrillation was provided by C.K. Kroell et al.3 It
was found that for impacts to the sternum in the range of 12.9 to 30.7 m/s, the
critical value for VC for a 50 percent probability of ventricular fibrillation is
1.46 + 0.31 m/s. The values of VC would go up if the fibrillation was accompa-
nied by heart rupture.
Mechanisms of Injury Derived from Crash Impact Research
To understand how a body region is injured by a blunt impact, we resort to
the accumulated knowledge in the field of impact biomechanics, a branch of
3Kroell, Charles K., Stanley D. Allen, Charles Y. Warner, and Thomas R. Pert. 1986. "Interrela-
tionship of Velocity and Chest Compression in Blunt Thoracic Impact to Swine II," 30th Proceedings
of the Stapp Conference, SAE Paper No. 861881, Society of Automotive Engineers, Warrendale, Pa.
5
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152
s
s
APPENDIX C
science that applies the basic principles of mechanics to biological systems, such
as the human body. One of the branches of impact Biomechanics is the study of
injury mechanisms, that is, how the injury is caused. It is beyond the scope of this
appendix to go into a detailed discussion of injury mechanisms from head to foot.
The reader is referred to the work of Albert I. King4 for what is known about
automotive-related impact injury mechanisms.
Several examples illustrate biomechanical aspects of blunt impact injury.
Ribs can fracture when a non-lethal round impacts the chest or when the torso
impacts a steering wheel. In both cases, the rib is bent and the inside surface of
the rib goes into tension. Since bone is weak in tension, fracture of the rib will
begin on the inside surface when the deflection of the rib reaches about 70 mm.
Similarly, in high-speed blunt impacts to the chest (more than 30 m/s), the
heart can go into ventricular fibrillation (ineffective pumping of blood) if the
impact occurs at or just prior to the T-wave of the electrocardiogram cycle; that
is, after the main signal has been sent to the ventricle to contract and to expel
blood into the aorta, the heart muscle goes into a refractory state for a short time,
the period of the T-wave. If the heart receives an impact at that time, the signal
to the ventricle is blocked for the next cycle and the ventricle goes into fibrilla-
tion. In a study of 24 cases of baseball-related impacts to the chest, mostly
against young children, none of the victims who went into ventricular fibrillation
could be revived, even if immediate cardiopulmonary resuscitation (CPR) was
administered. The probability of this happening with a non-lethal munition is
very low, but not zero. The exact mechanism as to why the conduction of the
signal for the ventricle to contract is interrupted is still being debated. If due to a
direct impact to the heart by the chest wall, then the condition can be prevented
by the use of a chest protector. However, if the mechanism of injury is the
passage of a pressure wave through the organ, the injury can be prevented only by
attenuating the wave before it reaches the heart.
Laceration of the lung can be due to contact of the lung with the broken end
of a rib, while contusion of the lung is more likely due to the same pressure wave
effect described above. However, the relationship between pressure magnitudes
and severity of lung injury is not fully known or understood.
Other examples of injury mechanisms consider brain injury, abdominal in-
jury, and spinal injury. For the brain, a blunt impact to the head causes local
deformation of the skull and movement of the head. This movement can be in the
form of a translational, or linear, acceleration and/or a rotational, or angular,
acceleration of the head. Current knowledge regarding mild traumatic brain
4King, Albert I. 2000. "Fundamentals of Impact Biomechanics: Part I—Biomechanics of Head,
Neck, and Thorax," Annual Review of Biomedical Engineering, Vol. 2, Eds. Martin L. Yarmush,
Kenneth R. Diller, and Mehmet Toner, Annual Reviews, Palo Alto, Calif., pp. 55-81; King, Albert I.
2001. "Fundamentals of Impact Biomechanics: Part II Biomechanics of the Abdomen, Pelvis, and
Extremities," Annual Review of Biomedical Engineering, Vol. 3, Ed. Roselyn Lowe-Webb, Annual
Reviews, Palo Alto, Calif., pp. 27-55.
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APPENDIX C
153
injury (MTBI) indicates that the cause is a combination of both forms of accelera-
tion, which can generate shear and pressure in the brain tissue. The precise
mechanism as to how these factors produce MTBI, including concussion and
mental confusion, is still being studied.
Injuries to the solid organs of the abdomen, such as the liver, occur as the
result of compression of the organ by the abdominal wall or rib cage. The
velocity of the abdominal wall is also a factor in causing the organ to rupture. In
contrast, the risk of spinal injury is very low; in fact, it is virtually impossible to
rupture an intervertebral disc in the neck or lumbar spine with any kind of a single
impact to the body unless there is a massive fracture of vertebral bodies immedi-
ately adjacent to the disk.5
Because of the eye's fragile structure and high deformability, any increase in
ocular pressure due to impact by a blunt projectile can cause permanent injury to
several different parts of the eye. In particular, the vitreous humor (a gel-like
material) in the rear of the eye, which is in contact with the retina, can produce
retinal laceration and detachment if deformed. Retinal injuries are frequently
permanent and non-restorable.
From these limited examples, it can be seen that even after 60+ years of
automotive safety research in impact biomechanics, the mechanisms of injury of
many body regions are not fully known or well understood. Non-lethal kinetic-
energy weapons add a new dimension to the problem because the speeds in-
volved are much higher and the masses involved are much lower.
-
.,
it
Recent and Current Human Effects Research on
Kinetic-Energy Munitions Experimental Studies
Research on the human effects of kinetic-energy rounds has been conducted
over the past two decades by many investigators in the United States, the United
Kingdom, and elsewhere (see below, Cooper and Maynard, 1986~.6 Among the
kinetic-energy munitions that have been studied, rubber-coated steel balls and
sponge grenades have been assessed in animal studies. Penetration of the thorax
and abdomen of the pig was investigated using these munitions. Animal studies
on the fracture risk of the mandible and ribs as well as on the potential of injury
to the heart, lungs, and intestines have also been conducted. Cadaveric studies on
the effects of baton rounds on the chest and of kinetic-energy rounds on brain
contusion and skull fracture have either been completed or are ongoing. A
SKing, Albert I. 1993. "Injury to the Thoraco-Lumbar Spine and Pelvis," Accidental Injury:
Biomechanics and Prevention, Eds. Alan Nahum and John W. Melvin, Springer-Verlag, New York.
pp. 441-443.
6Cooper, G.J., and R.L. Maynard. 1986. "An Experimental Investigation of the Biokinetic Prin-
ciples Governing Non-Penetrating Impact to the Chest and the Influence of the Rate of Body Wall
Distortion Upon the Severity of Lung Injury," Proceedings of the IRCOBI European Impact Bio-
mechanics Conference, Zurich, Switzerland.
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154
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APPENDIX C
-
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8
VC max
FIGURE C.3 Logist analysis of lung contusion as a function of VC. SOURCE: Cooper,
G.J., and R.L. Maynard. 1986. "An Experimental Investigation of the Biokinetic Princi-
ples Governing Non-Penetrating Impact to the Chest and the Influence of the Rate of
Body Wall Distortion upon the Severity of Lung Injury," Proceedings of the IRCOB1
European Impact Biomechanics Conference, Zurich, Switzerland.
human-surrogate rib cage, called the three-rib device, has been developed for
testing other types of blunt munitions of equivalent kinetic-energy levels. At the
present time, a study using the three-rib device to assess the response of the rib
cage to a variety of munitions, including the sponge grenade, the beanbag, and
other munitions, is in progress. The impact of sting balls (light plastic balls) on
porcine eyes is also being studied. It is not clear if accurate biomechanical
measurements are being made along with the study of injury potential.
The early work of Cooper and Maynard studied the effect of blunt projectiles
on the lung. A large series of porcupine experiments (43 tests) was conducted to
evaluate lung contusion, which was defined in terms of an increase in lung
weight. A 50 percent increase in weight was considered unacceptable. A Logist
plot in terms of VC is shown in Figure C.3.
Ventricular fibrillation tests were conducted on swine by Kroell et al.7 In the
41 tests conducted at impact speeds ranging from 9.7 to 30.7 m/s, with impactors
ranging in mass from 4.9 to 21 kg, there were 11 cases of ventricular fibrillation
7Kroell, Charles K, Stanley D. Allen, Charles Y. warner, and Thomas R. Pert. 1986. ``Interrelation-
ship of Velocity and Chest Compression in Blunt Thoracic Impact to Swine II," 30th Proceedings of
the Stapp Conference, SAE Paper No. 861881, society of Automotive Engineers, Warrendale, Pa.
OCR for page 155
APPENDIX C
1 -
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0.7 -
.
~ 06
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P = 1/(1 + exp (22.67 -17.52VCmax))
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VChlax (m/s)
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155
HR: VCmax = 2.69 +/- 0.86 m/s
: VF (with HR): VCmax = 2.13 +/- 0.85 m/s
VF (AIS 1-3): VCmax = 1.46 +/- 0.31 m/s
Sudden Cardiac Attest or Commotio Cordis
FIGURE C.4 Logist analysis of ventricular fibrillation (VF) as a function of VC.
SOURCE: Kroell, Charles K., Stanley D. Allen, Charles Y. Warner, and Thomas R.
Pert. 1986. "Interrelationship of Velocity and Chest Compression in Blunt Thoracic
Impact to Swine II," 30th Proceedings of the Stapp Conference, SAE Paper No. 861881,
Society of Automotive Engineers, Warrendale, Pa.
and 21 cases of heart rupture. In the non-lethal weapons context, ventricular
fibrillation is more relevant. A Logist curve for ventricular fibrillation as a
function of VC is shown in Figure C.4. As mentioned above, the value of VC for
a 50 percent probability of ventricular fibrillation is 1.46 + 0.31 m/s. (Note also
the steepness of the transition from no harm to irreversible effect. This is attrac-
tive for non-lethal weapons design in allowing a fairly crisp threshold for estab-
lishing margins of safety.)
Cadaveric tests on the tolerance of the chest to blunt projectile impact (ba-
tons) weighing 30 and 140 g and traveling at speeds of 20, 40, and 60 m/s were
carried out by Bir.8 A total of 13 cadavers was used and a total of 21 tests was
conducted, with a maximum of 3 tests on any given cadaver. If a rib fracture was
8Bir, Cynthia A. 2000. "The Evaluation of Blunt Ballistic Impacts of the Thorax," Ph.D. disserta-
tion, Wayne State University, Detroit, Mich.
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156
Cal
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APPENDIX C
-
Logistic regression model:
X2 = 11.279
p = 0.0008
R=.82
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
VCmax
FIGURE C.5 Logist analysis of rib fracture tolerance as a function of VC. SOURCE:
Bir, Cynthia A. 2000. "The Evaluation of Blunt Ballistic Impacts of the Thorax," Ph.D.
dissertation, Wayne State University, Detroit, Mich.
i.
detected either by x-ray or by palpation, testing on that cadaver was discontinued.
A Logist curve for rib fracture (less than 3) as a function of VC is shown in
Figure C.5. The tolerance in terms of a 50 percent probability of no more than
two rib fractures is O.8 m/s.
Although there are claims of data on brain contusion, skull fracture, maxilla
fracture, and liver laceration, no tolerance curves were presented to the commit-
tee, and none were found in the open literature. The impact of sting balls on pig
eyes is also being studied. Research on intestinal injury due to a pressure wave
has been conducted by Yu et al.9
Mathematical and Mechanical Models
The only mathematical model used extensively by the military for the predic-
tion of human effects due to kinetic-energy rounds is the Interim Total Body
Model developed by Jaycor for the Army. It is an outdated spring-mass-damper
9Yu, James H., Edward J. Vasel, and James H. Stuhmiller. 1990. "Modeling of the Non-Auditory
Response to Blast Overpressure~astrointestinal Tract Blast Injury Laboratory Test Techniques,"
Annual/Final Report to U.S. Army Medical Research and Development Command, Fort Detrick,
Frederick, Md., Contract No. DAMD17-85-C-5238, by Jaycor, San Diego, Calif. (Accession No. 90
07 2037).
OCR for page 157
APPENDIX C
157
model that was popular some 25 to 30 years ago.~° How the model was devel-
oped or how the data were obtained to populate the model parameters was not
described to the committee. It also appears that no attempt to validate the model
against experimental data has been made. Nevertheless' it is claimed that the
model is capable of predicting injuries to the brain, eyes, face, lungs, heart, liver,
spleen, hollow abdominal organs, and pelvic organs.
Differences in Munitions
. -
The many types of kinetic-energy weapons described above call for a con-
certed research effort to try to understand the human effects of these rounds on
various body regions. It can be seen from the previous sections that only a few
body regions have been studied in detail and that even fewer regions have toler-
ance curves, and then only for a limited number of projectiles. The potential
combinations of the many critical body regions with at least half a dozen different
types of kinetic-energy munitions call for the development of a unifying method
of tackling this problem, such as the formulation of a comprehensive finite ele-
ment model of the human body, capable of simulating impacts by these muni-
tions. During the development of such a model, the needed material parameters
would be identified, and running portions of the model to simulate regional
impact would identify the types of experiments needed to generate the necessary
data for the material constants and for validation of the model. The proposed
approach would not only reduce the number of animal and cadaveric tests needed
to achieve this goal, but also make such tests more useful. At the same time, the
experimental data can be used to obtain Logist curves to define human tolerance
to impacts by these munitions.
Of major concern are head and brain injuries. Grenade and mortar casing
fragment velocities have been measured at approximately 100 m/s; this poses a
risk to both the brain and the chest. ~ ~ It should be pointed out that there is no need
to create a new finite element model of the head and brain. One already exists,
and it can be adapted to kinetic-energy projectiles.l2 Tolerance of the eye to
impact by munitions of different shapes and sizes, traveling at different veloci-
ties, has not been established. Perhaps a VC-type criterion could be developed to
minimize the risk of permanent eye injury. Again, modeling to simulate the
iOMayorga, Col Maria, USA, "Interim Total Body Model," briefing to the committee, June 12,
2001, Walter Reed Army Institute of Research, Department of the Army, Silver Spring, Md.
1 1Bir, Cynthia A. 2001. "Thoracic Injury Assessment of the Modular Crowd Control Munition
(MCCM)," Final Report, Wayne State University, Bioengineering Center, Detroit, Mich., Contract
No. DAAE30-99-M-0222, National Institute of Justice.
12Zhang, L. 2001. "Computational Biomechanics of a Traumatic Brain Injury: An Investigation
of Head Impact Response and American Football Head Injury," Ph.D. dissertation, Wayne State
University, Detroit, Mich.
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158
APPENDIX C
various types of munitions should be attempted. Other areas of concern are the
face (disfigurement), the ear, the thorax, the abdomen, and the genital organs.
One of the difficulties encountered in assessing the injury potential of ki-
netic-energy rounds is the variability of conditions under which they may be
used. For example, a certain round has a design range of 50 m; that is, it can
cause enough temporary pain to effectively dissuade a perpetrator from advanc-
ing toward a defending force at this range. However, if the weapon is fired at a
target only 25 m away or hits an unintended target that is only 25 m away, the
impact may cause not only severe pain but also possibly permanent injury. A
weapon system equipped with a rangefinder and an adjustable firing pressure will
help solve the problem if the tolerance of the body region is known.
In a different example, a long-range kinetic-energy mortar can be made to
explode over a crowd assembling several hundred meters away. The munition
used could be lightweight, high-velocity pellets that are unlikely to cause perma-
nent injury. The canister carrying the munition can cause head injuries, however,
unless it is made into harmless shards itself or lands by means of a parachute as
the munition is released.
Another concern is injury to the eye. When pellets are dispersed indiscrimi-
nately over a crowd, there is again a non-zero probability that one of the pellets
will hit someone's eye. The chances are very small, because the eyes constitute
0.1 percent of the frontal body surface, but policy or field command must decide
if a 0.1 percent probability of a permanent eye injury is worth the risk.
.
6
Deficiencies in the Current Program
It appears that the development of kinetic NLWs is well ahead of the re-
search on human effects. Only a few of these munitions have been tested on live
animals and human cadavers, and there is no overall understanding regarding
human tolerance as a function of the mass and velocity of a round. In fact, the
scaling of tolerance data from the animal to the human has not been very success-
ful in low-velocity blunt impacts simulating automotive collisions; cadaveric
data were found to be much more reliable in defining human tolerance. Patho-
physiological responses cannot be obtained from cadavers, yet reliable numbers
on tolerance cannot be deduced from animal data. Research has been concen-
trated on the torso (chest and abdomen), where most of the rounds are expected to
strike, but these munitions can also cause permanent and critical injuries when
they strike the head, face, or eyes. A coordinated effort to study the injury
potential of non-lethal kinetic-energy munitions using both animals and cadavers
is needed to ensure that one truly has NLWs that fit the requirements of DOD
Directive 3000.1. The present structure does not allow for any control over the
development of these weapons inasmuch as human effects are not a primary
consideration when a weapon is designed and developed.
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APPENDIX C
in
159
Another method of assessing the mechanical effects of a kinetic munition on
the human body is to use computer models to simulate the impact. The interim
total body model currently in use by Army personnel, who are the leading Service
expertise in this area, is outdated. In the face of a large multitude of munitions of
varying mass and velocity, it is necessary for the non-lethal weapons community
to develop a more sophisticated computer model that could simulate a wide range
of blunt impacts. One promising approach is to take an existing finite element
model of the human body used in automotive safety research and adapt it to
simulate the impact of kinetic-energy munitions. Examples of these models can
be found in the impact biomechanics literature (Stapp Car Crash Journal and the
Proceedings of the Stapp Car Crash Conference). Finite element models can
simulate a variety of impacts by different munitions at varying velocities. How-
ever, all models need to be validated against experimental data. New data using
cadaveric subjects should be acquired. Alternately, animal data can be used, but
finite element models of the animals would have to be developed for validation
purposes. Moreover, the models need to be validated over a range of munitions
fired at varying speeds.
It is concluded that although kinetic-energy munitions are not as sophisti-
cated and versatile as some of the newer types of NLWs under development, they
still have several advantages. The principal advantages are the relatively low cost
of the munitions and the adaptability to existing guns and mortars. A need for
weapons that can be deployed rapidly at close range to defuse a suddenly devel-
oping situation is also still important. After the tolerance of the human to impacts
of kinetic-energy munitions has been determined, improvements to the weapon
systems can be made. These include new projectiles and rangefinders on weap-
ons that can control the speed of the projectile so that the target is impacted at a
relatively safe speed even if it is right at the muzzle.
C.3 CHEMICAL NON-LETHAL WEAPONS HEALTH EFFECTS
Chemical antipersonnel NLWs are intended to dissuade, temporarily inhibit,
incapacitate, or otherwise impede individuals and crowds from taking certain
actions while causing them no lasting serious side effects. Pepper spray (OC) and
tear gas (CS) are common chemical riot control agents; malodorants and calm-
atives are also potentially useful within the non-lethal weapons arsenal. These
two riot control agents and malodorants act by being so unpleasant, either by
irritation/inflammation or stench, that people leave an area.
The mechanism of actions for the riot control agents are fairly well studied.
Calmatives operate by depressing the central nervous system, but while they
offer some opportunity for crowd control, additional research will be required to
develop substances that provide reliable human response so as to achieve coop-
erative behavior changes versus physiological depression. Increasing concentra-
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160
APPENDIX C
lions of calmatives in the body can lead to a loss of consciousness and, ultimately,
death. Ideally, the level of exposure between an "effective dose" and death
would be a factor as high as 103 to 104. Major R&D issues involving the use of
calmatives will be (1) characterizing and quantifying the safety of the chemicals,
and (2) obtaining the method of delivery that will Provide the croner dose.
~ rear
C.4 DIRECTED ENERGY
This section addresses directed-energy NLWs based on radio-frequency elec-
tromagnetic fields or photons either as laser light or as non-coherent light.
Radio Frequency
. ~
. -
6
Radio-frequency energy, spanning direct current to gigahertz, interacts with
biological tissues primarily in conversion of the energy to heat. This thermal
bioresponse produces the desired effect in the current and near-term RF non-lethal
weapons systems. For example, in VMADS, the first NLW that uses millimeter
waves, energy is deposited within a fraction of a millimeter into the skin. This top
layer is heated within a few seconds, stimulating the pain receptors but not inducing
permanent damage. At present, the JWNLD program is evaluating human responses
to VMADS as a function of distance. Technical reports have been published on skin
heating and corneal damage in a laboratory setting. Because the millimeter wave-
length that VMADS uses is not associated with an existing radar system, little prior
information was developed on the safety aspects of the particular weapon concept.
The fraction of energy absorbed from the beam depends on the frequency of the
energy, the size and shape of the target, and the dielectric characteristics of the
target, which varies significantly from tissue to tissue. For humans, these relation-
ships and time-averaged power absorption form the basis for establishing the limits
of exposure to continuous RF to avoid burning.
Recent developments in broadening the bandwidth of RF generators and the
development of systems capable of producing very short pulses and very high
peak power provide a glimpse into the vast, unexplored region of biological
effects or human susceptibilities and potential avenues for NLWs. With such
new technologies, the body would be exposed to both low- and high-frequency
energy as well as to very high peak powers at some frequencies. The conven-
tional measure, the time-averaged absorbed power, would not be a good predictor
of relative safety with these systems, and it is not clear just which independent
parameters should be associated with safety regulations.
Pulsed RF fields are observed to produce a variety of effects that are not
understood. Moreover, leap-ahead technologies will require a much more thor-
ough knowledge of RF interactions with the human body than currently exists.
Such progress will require a prolonged effort by a multidisciplinary team of
researchers skilled in a wide range of disciplines.
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APPENDIX C
161
Lasers
Lasers are used in the non-lethal sense to function as both physiological and
psychological weapons. In the former, the goal is to obscure vision, either di-
rectly by interfering with eyesight or indirectly by light scatter. In the latter, the
laser is used as an illuminator to let adversaries know that they are targeted. (The
latter function was used successfully in tactical situations in Somalia.) Laser
weapons may be continuous or pulsed.
The method for obscuring vision can be by dazzling or by producing a form
of flash blindness by photoreceptor cell saturation. This results in "afterimaging,"
which gradually fades with time. Only wavelengths in the visible spectrum (400
to 780 nm) produce glare and flash blindness. The eye can also be obscured by
using a high-frequency laser that excites the lens to cause fluorescence within the
lens. Safety issues have been and continue to be a strong focus of research
because of the increasing utility of lasers in commerce, professional use, and
within military circles. The potential for a specific laser to produce ocular dam-
age depends on the type of laser, the distance from the laser to the target, the
energy of the laser, and total exposure time.
Laser wavelength is one of the most important characteristics for under-
standing effects. Wavelengths from 400 to 1,400 nm, known as the retinal hazard
region, are transmitted through the cornea and are focused on the retina. The
visible spectrum includes wavelengths from 400 to 780 nm and the near-infrared
includes wavelengths from 780 to 1,400 nm. The cornea and lens are capable of
concentrating laser energy 100,000 times before it reaches the retina. Lasers
operating in the visible or near-infrared spectra are therefore capable of produc-
ing severe photochemical and thermal choroidal or retinal damage. Lasers oper-
ating in the ultraviolet spectrum (200 to 400 nm) are also capable of producing
eye damage, but the retina is usually spared because of the high absorption of
ultraviolet in the outer part of the eye. Other lasers operate in the far-infrared
with wavelengths above 1,400 rim and are also absorbed by the cornea and lens.
These lasers may produce corneal burns or cataracts, but no energy is transmitted
to the retina. Sufficient data are available for the American National Standard for
safe use of lasers to be promulgated for continuous and pulsed (down to the
nanosecond time frame) systems that operate at wavelengths between 180 rim
and 1 mm.
To exploit lasers for use as NLWs to their maximum potential, specific
programs will be required to evaluate the susceptibilities of humans to a wide
range of modalities at eye-safe light intensities. This type of work follows devel-
opment of guidelines on eye safety for well-studied systems but may require
additional study for unexplored modalities. While the phase space requiring
exploration for lasers may not be as great as that for RF systems, there is still a
significant region of unknowns. It will be necessary to understand the potential
for visual disruption as a function of the photon wavelength, use of multiple
wavelengths, pulse shapes, interexposure intervals, and the effects of cofactors.
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62
APPENDIX C
The use of cofactors might be considered in the search for synergistic effects
of directed-energy systems. Confusion, the influence on temporary memory, and
additional stages of neural disruption might be assisted by the application of
multiple stimuli, properly timed. The demonstrated psychological effects related
to illuminating human targets in Somalia illustrate the desirability of an accompa-
nying psychological line of study.
C.5 ACOUSTIC NON-LETHAL WEAPONS
-
Non-lethal acoustic weapons have been discussed at great length in the
literature as having the potential for being able to change behavior. The
gross effects often described as effecters are pain, presence of irritating/
aggravating noise, or the production of uncomfortable internal organ condi-
tions. Several acoustic technologies fit under the label of non-lethal, but
might be more appropriately considered in the realm of psychological tools
or communication technologies, depending on the use to which they are put.
Although repeated attempts have been made to develop high-intensity sound
generators capable of eliciting desired results, a consistent set of reliable
data, demonstrating aversive effects while not producing deafness, has not
been forthcoming.
A technology of this type, useful for the same kind of applications, is that
derived by sending two separate ultrasonic signals that are above the human
hearing range of about 20 kilohertz (kHz). These two signals can be aimed at an
individual or reflecting surface to constructively mix and produce normal audible
signals, such as voice and music. Two commercial companies offer systems that
could be evaluated for operational effectiveness.
Combined use of these two acoustic signal technologies offers the potential
for synergy, principally in the psychological arena.
C.6 ELECTRICAL NON-LETHAL WEAPONS
The class of weapons known as lasers (aka stun guns) are NLWs acting by
injection of electrical current into the human. Tasers operate either by direct
contact from the weapon or by means of darts with wires attaching to the weapon.
Once the dart contacts the human, high-voltage but low-amperage electrical cur-
rent is discharged. The actual mechanism of action is not well studied, but the
commercial devices are effective.
Proposals to develop wireless lasers are intriguing because of the potential
for significant standoff.~3 Mechanisms of action must be understood and safety
13A reviewer of this report suggested a laser that includes a substantial round with a soft front end
and a couple of darts to shoot into the clothing and convey an elecrical shock. The round could
contain a capacitor charged before the round is fired.
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APPENDIX C
163
tolerances must be developed because such a weapon, if developed, could be
applied at distances that would make it difficult to identify some potential recipi-
ents. Such tolerances must be known in order to develop rules of engagement for
this type of weapon, since there may be a range of tolerances depending on the
age, size, gender, and other physical conditions.
C.7 BARRIERS AND ENTANGLEMENTS
Effect of Barriers and Entanglements
Most barriers and entanglement systems are designed for area denial to
personnel and/or vehicles, including ships and boats. Barriers that present con-
cerns regarding human effects include caltrops, concertina wires, webshots and
entanglement grenades, tire spikes, and portable vehicle arresting barriers (PVABs).
Caltrops and concertina wires are designed to deny pedestrian entry into an area
by the obvious injury that will be incurred if entry is attempted. Webshots and
entanglement grenades are designed to stop fleeing individuals by firing a net
over them and entrapping them long enough for the pursuer to reach them. Tire
spikes and PVABs are designed to stop fleeing vehicles, and injury may result if
there is a crash or if the PVAB fails.
Mechanisms of Injury
Caltrops and concertina wires can cause lacerations and punctures, particu-
larly to the extremities. The injuries are rarely unintended, unless an innocent
civilian wanders into the restricted area at night and fails to notice the presence of
the barriers. The injuries are not expected to be permanent, however, unless the
individual is determined to break through the barrier. Webshots and entangle-
ment grenades are not expected to cause major or permanent injuries unless the
fugitive happens to hit his or her head on a hard surface during a fall. The
probability of that happening is expected to be low. Other injuries can include
twisted ankles and wrists and bruises and contusions, none of which is perma-
nent. As for tire spikes, the only risk is the loss of control of the vehicle after the
tires are blown, particularly if only one is blown. The vehicle may crash into
some other barrier, injure nearby pedestrians, cyclists, or vehicular occupants, or
roll over. It may also crash into a building, injuring its occupants. Thus, the site
of deployment needs to be carefully selected. The risk of serious or fatal injury to
the occupants of the fleeing vehicle also needs to be considered, especially since
fugitives are not likely to use belted restraints. Fatalities can occur when unbelted
occupants are ejected in a rollover. PVABs have been tested at 45 mph. A risk
exists for head and neck injuries to unbelted occupants at that speed. The system
has not been tested at higher speeds, and the resulting injuries are unknown but
are expected to be more severe than at 45 mph. If there is failure of the PVAB
system before arresting the vehicle, a crash may occur.
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164
Recent and Current Studies
APPENDIX C
The injuries that can be caused by caltrops and concertina wires have not
been studied. The obviousness of their injury potential does not justify any re-
search. While webshots and entanglement grenades appear to present a very low
probability of permanent injury, prevention of a severe head injury is neverthe-
less difficult in this situation and the state of the art in computer modeling of this
event is currently unable to simulate human muscular response, particularly since
it is totally unpredictable. The injury mechanisms involved in the use of tire
spikes and PVABs are the same as those observed in automotive crashes. Un-
belted occupants are more at risk than belted ones, regardless of whether the
vehicle is equipped with airbags or not. The severity of the injury depends on the
crash velocity and increases with older and smaller vehicles.
C.8 PSYCHOLOGICAL EFFECTS
The main purpose of NLWs is to change the behavior of opponents while
minimizing collateral damage. For this reason, psychological and behavioral
studies are an important adjunct to the development of NLWs. Studies should
seek to understand the behavioral responses to NLWs and the psychological
effects and effectiveness of these weapons.
An example of the kind of behavioral effects that are important to understand
might be the response of a crowd to the use of VMADS. What might be the
response of subjects caught in the VMADS beam with others close by? Given
this information, techniques that it would be possible to develop would most
likely cause people to move away from the target area as opposed to panicking.
Similarly, it would be useful to have more understanding of the response of
people from different cultures to specific malodorants and when exhibiting dif-
ferent levels of aggression.
Because NLWs are applied with the intent of clearing, dissuading, blocking,
or otherwise causing peaceful changes in behavior, it is important to thoroughly
understand people's responses to them and behaviors as individuals or in the
context of the crowds and confined spaces likely to be encountered in missions.
Recent developments in broadening the bandwidth of RF generators and the
development of systems capable of producing very short pulses and very high
peak power provide a glimpse into the vast unexplored region of biological
effects or human susceptibilities and potential avenues for NLWs. Single pulses
of RF energy have been associated with stun and seizure, decreased spontaneous
animal activity, microwave-induced whole body movements, thermal sensations,
and startle modification. Some of these effects may be associated with the
activation of specialized nerve endings and/or may be only partially mediated by
heating. Little evidence has been identified to suggest that a bioelectromagnetics
program exists to explore the vast domain of RF energy for application to NLWs.
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165
The present VMADS system and those under development are based on knowl-
edge initially gained decades ago. Leap-ahead non-lethal weapons technologies
will require a much more thorough knowledge of RF interactions with the human
body than is in existence or can be envisioned within the current programmatic
plans of the JNLWD. Such an effort would require a prolonged effort by a
multidisciplinary team of researchers skilled in a wide range of disciplines.
Likewise, to exploit lasers for use as NLWs to their maximum potential,
specific programs would be required to evaluate the susceptibilities of humans to
eye-safe light intensities. It will be necessary to understand the potential for
visual disruption as a function of the photon wavelength, use of multiple wave-
lengths, pulse shapes, interexposure intervals, and the effects of cofactors.
The use of cofactors might be considered in the search for synergistic effects
of directed-energy systems. Confusion, temporary memory, and additional stages
of neural disruption might be assisted by the application of multiple stimuli,
properly timed. The demonstrated psychological effects related to illuminating
human targets in Somalia demonstrate the need for an accompanying psychologi-
cal line of study.
The main purpose of any weapon is to change the behavior of an opponent.
Given the non-lethal weapons goal of changing behavior while minimizing col-
lateral damage, opportunities must be sought to understand how to optimize
psychological effects toward change of behavior within the context of available
and desired NLWs. Only cursory consideration is now given to the use of
existing weapons systems for psychological advantage, but it seems within the
realm of possibility that systems might be developed with that in mind.
Examples of psychological effects were identified in the preceding sections
on specific health effects. Much opportunity seems possible using systems that
are explicitly designed to enhance communication, since information exchange is
a principal medium of psychological effects. Notable among these were the
acoustic technologies that provide communication through vastly different means.
In addition to the intended targeting of psychological effects are the effects that
might be associated with kinetic-energy, directed energy, or chemical systems. Of-
ten these are applied with the intent of clearing, dissuading, blocking, and so on.
Unless these weapons systems are thoroughly studied in the context of crowds as
well as of individuals in both open and confined spaces, there could easily be
unintended consequences as a result of undesirable psychological responses.
it
/
Representative terms from entire chapter:
human effects
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