Journal of Natural Fibers,
Год журнала:
2024,
Номер
22(1)
Опубликована: Дек. 28, 2024
This
study
focuses
on
optimizing
drilling
parameters
to
minimize
delamination,
circularity
error,
and
cylindricity
in
natural
fiber
composites
through
a
comprehensive
full
factorial
Design
of
Experiments
(DoE)
combined
with
Grey
Relational
Analysis
(GRA).
The
novelty
this
work
lies
its
systematic
integration
these
methods
evaluate
the
effects
spindle
speed,
feed
rate,
drill
type
(HSS,
HSS-Co,
Solid
Carbide)
hole
quality,
providing
robust
framework
for
multi-response
optimization.
Results
reveal
that
rate
is
most
significant
factor,
optimal
conditions
–
lower
rates
(0.04
mm/rev)
moderate
speeds
(1592
rpm)
delivering
reduced
delamination
improved
quality.
Among
tested
drills,
Carbide
demonstrated
superior
performance
lowest
errors.
highlights
potential
parameter
optimization
advance
eco-friendly
composite
manufacturing
enhance
precision.
Journal of Engineering Research,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 1, 2024
Pre-damage
and
undetected
micro-defects
in
fiber-reinforced
polymer
(FRP)
composites
are
significant
challenges
compromising
the
integrity
mechanical
performance
of
composite
structures
aerospace
applications.
To
address
this
challenge,
experimental
study
investigated
low
velocity
impact
(LVI)
compression
after
(CAI)
behaviors
carbon
fiber/epoxy
(CF/E)
reinforced
with
0.0
(control
sample),
0.2,
0.4
wt%
helical
multiwalled
nanotubes
(HMWCNTs).
The
LVI
test
results
showed
that
control
samples,
epoxy
as
predominant
phase,
registered
lowest
peak
force
compared
to
0.2
wt
HMWCNT/epoxy
laminates.
CAI
a
decrease
strength
increased
energy
an
increase
weight
percent
HMWCNTs.
Consequently,
HMWCNT
ladened
could
withstand
higher
load
without
undergoing
deformations,
exhibiting
highest
resistances
due
presence
CNTs,
which
function
load-bearing
material.
interleaved
CF/E
laminate
samples
subjected
25
J
achieved
maximum
9870.25
N
8527.26
for
damaged
at
same
level
energies.
This
fact
indicates
not
sufficiently
high
forces
local
instability
arising
from
existing
damages.
strongly
suggest
potential
HMWCNTs
CF/epoxy
making
structural
substructural
components
aircraft
automobiles
their
proven
superior
properties.
Abstract
This
study
developed
a
zeolite-modified
ecological
concrete
and
investigated
the
effects
of
zeolite
content
particle
size
on
its
physical
mechanical
properties,
as
well
degradation
performance.
Experimental
results
demonstrated
that
for
given
zeolite,
an
increase
in
led
to
higher
compressive
strength.
Conversely,
with
constant
content,
strength
blocks
increased
larger
sizes.
In
water
purification
tests,
reduction
enhanced
melanin
removal
rate.
Specifically,
when
was
0.5–1
mm
20%,
rate
reached
62.4%.
At
this
composition,
efficacy
optimal,
their
properties
met
necessary
application
standards.
This
study
investigated
elite
athletes’
aerobic
exercise
recovery
period
based
on
ECG
and
near-infrared
spectroscopy.
explores
the
integration
of
electrocardiogram
(ECG)
signals
cerebral
oxygenation
levels
to
classify
recovery.
Skiers
perform
20
min
roller
skis.
The
ensemble
empirical
mode
decomposition
is
employed
decompose
signal
into
intrinsic
functions.
non-linear
indices
spectroscopy
were
calculated
during
after
exercise.
t-distributed
stochastic
neighbor
embedding
(t-SNE)
applied
visualize
combined
feature
space
oxygenation.
results
show
that
there
a
decrease
in
sample
entropy,
approximate
Shannon
closely
related
an
increase
concentration
oxygenated
hemoglobin
deoxygenated
Classification
accuracies
96.2%,
85.6%,
91.3%
are
achieved
using
features
2D
t-SNE
99.5%,
97.9%,
96.1%
3D
K-Nearest
Neighbors,
Support
Vector
Machine,
Tree
classifiers,
respectively.
These
findings
underscore
potential
integrating
for
classification.
