SELECTION CRITERIA TOOL
by:
Susila Krist ianingrum
susila.k@uny.ac.id
Basic compet ency:
Choosing t he right t ool in t he
procurement of equipment
•
How t o choose a good / correct as needed and funds are available?Criteria for a good tool
Aspect s of academic /
pedagogic
physical aspect s
Aspect s of academic /
pedagogic
Can be used for:
1. Inst illing t he concept of an exist ing chemical
2. Reveals a new concept of chemical
3. St imulat e st udent s' t hinking t o const ruct a generalizat ion
4. Accelerat e t he learning process of children
Physical aspect s
•
Usabilit y of t he t ool•
st ruct ure t ool•
reliabilit y t ools•
mat erial t ool•
size of t ool•
shape t ool•
pract icalit y t ools•
value reparat ionsUsabilit y of t he tool
•
The t ool can be used for several t ypes of experiment s, several laborat oriespH M eter (Orion 3 Star) and pH Combination Electrode Calibration
Procedure:
Note: The pH meter and pH combination electrode must be calibrated each day before use.
The ATC probe must be used during calibration of the pH probe and during pH measurement of samples.
1. Bring the temperature of the pH buffers and samples to room temperature before beginning calibration procedure. All solution temperatures should be within ±3 °C of room
temperature.
PROCEDURE
pH M eter (Orion 3 Star) and pH Combination Electrode Calibration
3. Press t he ON/ OFF button to turn the meter on. To set the pH meter parameters press the Setup button. Press the Line Select button and use the dow n arrow key to change the display t o bUF. Press the Line Select key again to accept the selection and move to the next line. The t hird line should display USA. If not, use the up and dow n arrow keys unt il USA is displayed. Press the Line
Select key once more to accept that selection. Press t he M easure key.
4. To calibrat e t he pH met er and elect rode w hile in t he measurement mode, press t he up arrow key unt il t he pH icon is displayed on t he right side of t he display. Then press t he Calibrate key to begin the calibration process. The meter w ill display CAL.1 on bottom
PROCEDURE
pH M eter (Orion 3 Star) and pH Combination Electrode Calibration
5. Begin calibration by removing the pH electrode from the storage solution, removing the plug from hole for the internal filling solution, rinsing the electrodes (pH and ATC) with deionized water and blotting dry with a Kimwipe®.
6. Place the electrodes into the bottle containing the pH4.00 buffer and a stir bar. Stir at a slow speed. When the meter indicates that a stable reading has been
obtained for the pH 4.00 buffer (pH icon stops
blinking), press the Calibrate button on the meter. The meter will display CAL.2 on bottom display line.
PROCEDURE
pH M eter (Orion 3 Star) and pH Combination Electrode Calibration
7. Remove the electrodes from the buffer, rinse with deionized water and blot dry.
8. Repeat steps 6 and 7 for the pH 7.00 and 10.00 buffers. After the pH 10.00 buffer has been used for the
calibration and the “pH icon” stops flashing, press the Measurement key to save and end the
calibration. The meter will display the electrode
slope. This should be recorded in an equipment- or project-specific notebook. The slope should be
The simplicit y of form / st ruct ure
•
Form a simple t ool / not complicat ed•
Facilit at e t he process of dat a collect ion facilit at e t he useReliabilit y
Reliable t ool if:
Can be used by anyone, anyw here, w it h similar result s
Terms: easy t o read scale
Qualit y materials
•
Good t ools are made of qualit y mat erials w hich are not easily damagedexample:
Glass pyrex or Jena
Size of tool
Depending on t he int ended use of t he t ool for: pract icum
Performance / forms
The shape is int erest ing and subt le no rough
Pract icalit y
Easily st ored and t ransport ed so as not t o fast
damaged
Repair
•
Ease of repair, do not cont inue t o wast e disposableSecurit y
•
Aid wearer safet y is assured•
Not easy t o pose a hazardAspect s of special assessment
•
sensit ivit y:Gauge t he influence of somet hing know n fact ors (t emperat ure, humidit y, pressure, w ind) t o change t he appoint ment is t o have
•
high sensit ivit y•
availabilit y of st ock•
ThoroughnessAssessment of an inst rument table
Aspect w eight Sum infor
mati on
1 2 3 4 value value
Akademic 5
Usabilit y of t he t ool 4
The simplicit y of form / st ruct ure
4
Reliabilit y 1
Qualit y mat erials 2
Size of t ool 3
Performance/ forms
1
Pract icalit y 2
Repair 1
Examples of circumst ances gauges
offered
specification Volumetric glass A Volumetric glass B Volumetric glass C
Size 100 ml 100 ml 100 ml
M aterial pyrex nat ron Jena
Scale/ table etched / painted painted etched
Diameter 3 ml 5 ml 5 ml
Dasar alat glass Glass & plast ic glass
Examples of t he tool table A, B,
and C
No Value Value Value weight ∑ ∑ ∑ Infor mation
Aspect A B C Value A B C
Provision
•
Range of values 1-4•
1 : minimum value•
4 : maximum value•
Tot al weight value = 25•
Tot al maximum value = 4 x 25 = 100Determinat ion of purchase
Total value Price
A 85 30.000
B 70 20.000
Terms of t he value of at least 60
•
M eans t hat all eligibleExample Ranking Reasonable
Value Price (Rp) Conversion Price Ranking reasonable
A 85 30.000 85/ 85x30.000 30.000 (3)
B 70 20.000 85/ 70x20.000 24.285 (1)
Tools purchased are B
The reason:
1. Once convert ed it t urns out t he most
reasonable price is wort h 85 B because if t he price is 24 285 (bid of Rp 20,000)
2. So even t hough t he B value is only 70, but
