VISUAL DATA

Qualitative Analysis Qualitative Analysis –– What it isWhat it is

Qualitative analysis is the process of interpreting such data collected during the course of (qualitative) research

Types of Qualitative Data

Textual Visual

Document Narrative Observational Field Notes

Photo-graphs

Video

Interview trancript

Diaries, letters,

etc.

Analysis of Visual DataAnalysis of Visual Data –– How ?How ?

Direct observation :

A method to get qualitative information from a happening is by a visual observation. This can be done by making direct observation (observational field notes), photographs, video.

• Less dependent on visual equipment• Heavily rely on observer “(visual) memorizing” capability• More suitable for a “static” to “very slow” happening

Photographs : • Depend on visual equipment and visualization technique• Heavily rely on visual quality of captured image (spatial

resolution)• Suitable for a “static” happening• Set of photographs less dynamic happening

Analysis of Visual DataAnalysis of Visual Data –– How ?How ?Video :

• Depend on visual equipment and visualization technique• Heavily rely on visual quality of captured video image

(spatial and temporal resolution)• Suitable for a dynamic happening

Analysis of Visual DataAnalysis of Visual Data

Less than 0.15 mm/sParticles slippageAbout 400 particles/cm3Number densityLess than 2 mDroplets diameterAtomizer (nebulizer) typeSeeding generator

= 50 mm2/s ; = 0.91265 g/ml ; Tboil = 300 oCPhysical Properties

Dimethyl Silicone Oil (Toshiba, TSF 451-50)Particles typeParticle Seeding System

Varied no more than 3% from peak at center (within assessment region)

Laser sheet intensity

Thickness, t = 0.4 mm Laser sheet

4W- Ar+ laser (Coherent Innova)Light source

Laser Light Sheet (LLS)

280 dpiResolution480 x 640 (.avi format)ImageAV master video captureDigitizing1/2000 s (shutter speed)Exposure1000 frame/sRecording

High speed video cameraCameraVisualization

LLS Technique

Analysis of Visual DataAnalysis of Visual DataLLS Technique

x

y

zMonitorPC + interface

Video player

Mainairflow

Laser source

Lensarrangement

Video camera

Reflector

Exhaust

Seeded nitrogen gas

lf

Settlingchamber nozzle

Contraction

20 mmStep height

1 mmSlot width

c.s = 50x80 mm2

length = 300 mmTest section

Analysis of Visual DataAnalysis of Visual DataAn analysis of visual data generally comprises of two parts (no need to be sequentially stated) :

• Descriptive part• Interpretation part

Key questions for analysis : Descriptive part :

• What is the (spatial, temporal, conditional) setting of the image?

• What is the main subject of the image?• Does it include other elements than main subject?

Interpretation part : • What is the main activity/happening of the (subject of)

image?• Does there seem to be any trend/pattern/theme to a set

of photographs (sequence of video images)?

Analysis of Visual DataAnalysis of Visual Data –– Example 1Example 1

Analysis of Visual DataAnalysis of Visual Data –– Example 1Example 1

Another set of images in Fig. 3.4(b) shows that in the case of injection with I = 0.04 and 0.1, the jet trajectory is highly deflected toward the upstream, and cannot sustain its growth too far. The jet trajectory breaks up soon and the gas distributes rather uniformly in the recirculation zone. This result suggests that the injected gas mixes rapidly with the recirculating airflow and without deep penetration, which might be attributed to the domination of strong turbulence and high reverse velocity of flow near the injection port. Meanwhile, a more extensive growth of the injected gas jet which penetrates through the shear layer can be observed in the case of I = 0.3. Mostly, the trajectory deflects downstream, indicating that it penetrates up to the region where the free stream comes into effect.

Analysis of Visual DataAnalysis of Visual Data –– Example 2Example 2

Analysis of Visual DataAnalysis of Visual Data –– Example 2Example 2

Fig.4.17. show the fractograph under different sintering temperature. The STS 316 nanopowder necking was formed at 800°C, and rapidly growth at 900°C. The lower necking formation and growth of nanopowder is due to higher surface area. Secondary phase was observed under Scanning Electron Microscope (SEM) as globular particle. It was found above 1000°C. This particle will reduce the ductility of sintered part with poor bonding strength with austenite matrix. This particle sizes was increase and was joined each other with sintering temperature. It indicates that secondary particle has higher melting point than STS 316.

Exercise Exercise of Visual Analysisof Visual Analysis

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Suggested AnalysisSuggested Analysis

PhotographerPhotographer’’s response to suggested s response to suggested analysisanalysis