Andreas Tommy Parlaungan Manurung

I've got Bachelor Degree and Master Degree from University of Indonesia Majoring Accounting. Having Bachelor Degree at Bina Nusantara University Majoring Informatics Engineering. I obtain Ak. (Accounting Professional Education Program) dan CA (Chartered Accountant) from University of Indonesia either. I get Law Degree from Universitas Terbuka (Indonesia Open University). Now, as my passion and interest, I am pursuing Bachelor Degree in Mechanical Engineering at STT Immanuel Medan.

Update-Purpose Post of the day: Gypsum Self-Leveling Concrete! Semakin sempurna aka WARNA DOFF (100% tidak memantulkan cahaya)!!

ChatGPT:

🌑 Gypsum Self-Leveling Concrete:

Light Reflectance Explanation

✅ Is it 100% non-reflective?

YES aka NEARLY !!
Gypsum-based self-leveling concrete has a very matte, low-luster finish.
It absorbs most light instead of reflecting it.
Reflectivity is extremely low, though not literally 0% — no material is perfectly black or absorbent unless it's engineered to be (like Vantablack).

📉 Estimated Light Reflectance (LRV)

Typical gypsum self-levelers:
LRV = 10–30, depending on exact formulation and finish.
- Lighter-colored ones reflect more.
- More porous/dusty surfaces reflect less.

For comparison:

Glossy white paint → LRV ~ 85–90

Matte gray concrete → LRV ~ 25–40

Flat black paint → LRV ~ 5–10

Vantablack (ultra black material) → LRV ~ 0.036