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History Of Reliable Sources To Learn About Nobelium.

Atomic Number: 102
Atomic Symbol: No
Atomic Weight: 259
Electron Configuration: [Rn]7s²5f¹⁴
History
(Alfred Nobel, discoverer of dynamite) Nobelium was unambiguiously discovered and identified in April
1958 at Berkeley by A. Ghiorso, T. Sikkeland, J.R. Walton, and G.T. Seaborg, who used a new
double-recoil technique. A heavy-ion linear accelerator (HILAC) was used to bombard a thin target of
curium (95% 244Cm and 4.5% 246Cm) with 12C ions to produce 102No according to the 246Cm(12C,
4n) reaction.
In 1957 workers in the United States, Britain, and Sweden announced the discovery of an isotope of
element 102 with a 10-minute half-life at 8.5 MeV, as a result of bombarding 244Cm with 13C nuclei.
On the basis of this experiment, the name nobelium was assigned and accepted by the Commission on
Atomic Weights of the International Union of Pure and Applied Chemistry.
The acceptance of the name was premature because both Russian and American efforts now completely
rule out the possibility of any isotope of Element 102 having a half-life of 10 min in the vicinity of 8.5
MeV. Early work in 1957 on the search for this element, in Russia at the Kurchatov Institute, was marred
by the assignment of 8.9 +/- 0.4 MeV alpha radiation with a half-life of 2 to 40 sec, which was too
indefinite to support discovery claims.
Confirmatory experiments at Berkeley in 1966 have shown the existence of 254-102 with a 55-s half-life,
252-102 with a 2.3-s half-life, and 257-102 with a 23-s half-life.
Following tradition giving the right to name an element to the discoverer(s), the Berkeley group in 1967,
suggested that the hastily given name nobelium along with the symbol No , be retained.
Isotopes
Ten isotopes are now recognized, one of which -- 255-102 -- has a half-life of 3 minutes.

25 Things Most People Don't Know About Ready-mix Batching Plant Daily Check List
All the Questions should answer with Yes or No or Explanation

Check Dune Sand Clean/Lot of Deleterious/Rubbish materials seen Have we segregated such material away from stock bins (in the enclosed containe

01 Check aggregate for size and shape (Visual only)
40mm yes/ no
20mm yes/No
10mm Yes/No

02 Check NWS. (Test Result)
5mm yes/no
Dune sand yes/ no

3 Check Dune Sand Clean/Lot of Deleterious/Rubbish materials seen Have we segregated such material away from stock bins (in the enclosed container)
Yes/no

04 Is Coarse aggregate storage bins properly cleaned of dus in the last 24 Hr ?
Yes/ no

05 Is there any cross contamination of raw materials any where? (in storage bins/hoppers)
Yes or no

Are the gratings /screens of plant bins in good condition to avoid entry of over size material entering in?
Yes/ no

06 Any other comments related to aggregates:
Explain

07 Are all the admixtures drums stored in proper place (protected from sun and dust)? (Ensure that the barrels are properly covered wirth lid)
Yes/ no

08

a) Are all the bags of microsilica stored properly? (the bags should not be kept open and exposed directly to sun, should be protected by coverting with tarpaulin sheets) yes or no

b) Is there any wastage of microsilica taking place? (Near Sila / Storage location)
Yes or no

c) Are spillages of microsilica cleaned?
Yes or no

09 Did you find any raw material being at very low stock? Not received yet for new supply to be started?
Yes or no

10 Any complaint frm batchers about any batching errors?
Yes or no

11 Have they cleaned the mixer in last 24 Hrs?
Yes or no

12 Any unusual complaints on production reported by batching plant operator or technician?
Yes or no

13 Are they using the right moisture content & absorption values provided by the laboratory for batching?
Yes or no

14 Did you verify the batching details w.r.t cement type, content, mixing time & temp for the daily concrete schedule?
Yes or no

15 What is the smallest batch cycle they have run in last 24 Hrs?
Explain

M3 errors within the tolerance limits?
Explain

16

a) is there any new batcher who started to do the batching?
Yes or no

b) is there any new shovel operator who started to load the raw material?
Yes or no

c) Is there any new cement bulker off loader started to do work?
Yes or no

17 Is there any complaint from the plant technician/ operator about leakage of truck mixer water valve? Have we informed the plant co-ordinator about the complaint?
Yes or no

18 Are there any problems in supply of concrete at the specified temperature? (Like have we faced any problem of with ice plant in last 24 Hrs? Due to which we are not able to supply concrete at specified temperature?)
Yes or no Explain

Any batching aborted at the plant? Reasons? What was done with the aborted concrete? Furnish details
Yes or no Explain

19 Are there any problems in meeting the specified workability at sie?
Yes or no

20 Arjmme we supplying concrete of low workability/high workability (compared to specified slump)? Is there any mix in which we are finding problems (abnormal) in production? (Like not getting required / over slump for given dosage of admix and moisture) Which site and grade of concrete?
Yes or no

21 Are there any complaints about the quality of concrete mix? (Like mix is Harsh/Sandy/High bleeding/More slump loss/ Delayed in setting/Short measure/Ony few trucks had harsh mix) Please furnish the details here below.
Yes or no Explain
22

a) Is plant technician taking all the samples as per required sampling plan?
Yes or no

b) Are the equipments used by the technicians in proper condition/calibrated?(Like Cube moulds are properly Cleaned & Oiled. Concrete dial thermometer / measurement tapes affixed with the calibration certificates)
Yes or no

c) What is the time of demoulding batching plant cubes and shifting to lab?
Explain

d) Any technician, who is new to concrete sampling at batching plant started to work? (Discuss with him and observe his work frequently).
Yes or no

e) Have we deviated with planned sampling Vs actual sampling in last 24 Hrs? If so What is the reason & what corrective action implemented?
Yes or no

23 Any rejected/returned/diverted (regraded) concrete in last 24 Hrs? If so furnish the details below.
Yes or no

24 Is the variation in any 3 days/7 days / 28 days cube alarming for any given concrete? Furnish the details
Yes or no Explain

25 Any untoward incident of safety which happened in production in last 24 Hrs?
Yes or no

The Emerald Ring of Polycrates

According to Herodotus, Amasis thought Polycrates was too successful, and advised him to throw away whatever he valued most in order to escape a reversal of fortune. Polycrates followed the advice and threw a jewel-encrusted ring into the sea; however, a few days later, a fisherman caught a large fish that he wished to share with the tyrant. While Polycrates' cooks were preparing the fish for eating, they discovered the ring inside of it. Polycrates told Amasis of his good fortune, and Amasis immediately broke off their alliance, believing that such a lucky man would eventually come to a disastrous end.[46] Within Herodotus' work, this story serves to advance general themes about the mutability of fortune and how to judge success. Most subsequent references to Polycrates in literature and other media have focused on this story.

Herodotus, Father of History (circa 490 to 420 BC). tells the story of King Polycrates of Samos. The king's luck was legendary, but Amasis, an Egyptian colleague, warned him in a letter, "I am pleased to hear, dear friend, that you are doing well; but your abundance of luck gives me pause for thought, as I fear the jealousy of the gods. So take my advice and protect yourself from luck. Reflect on what you love the most, and whose loss would cause you the greatest pain, and throw it away, so that it will never appear again."

When Polycrates had read the letter and had seen that Amasis' advice was good, he considered which of his royal treasures he cherished most. He discovered that it was the emerald set in the gold ring he wore on his finger and used as a seal. It was the work of Theodoros, son of the Samian Telekles. Polycrates decided to dispose of the ring. He summoned a ship with fifty rowers, boarded and ordered the ship out to sea. When he was far from the island, he took off the ring and with all eyes watching. threw it into the sea. He then returned home and was distraught.

Some days later a fisherman honored him with the gift of a large catch:

The fish was opened by the cook,

Who suddenly, with wondering look,

Runs up, and utters these glad sounds. "Within the fish's maw, behold.

MAKE YOUR CONCRETE MORE DURABLE

Fresh concrete has an inhurent tendency to crack and preventive measures at hthe time of placing and curing remain the best means of minimicing cracking

When concrete is placed under high ambient temperatures / low humidity / windy conditions, cracks appear during the setting/hardening period due to evaporation of water from the concrete surface.

Cracks appear in winter also under windy conditions. Further delay in curing would widen and deepen such cracks thereby causing leakages through slabs.

These cracks are known as PLASTIC SHRINKAGE cracks and are commonly observed in concrete footings and slabs. These cracks are classified as non-structural and do not affect structural stability; however, the cracks have to be sealed to achieve the intended serviceability of the structure,

PREVENTIVE MEASURES TO REDUCE AND CONTROL PLASTIC SHRINKAGE
Concrete surface,PREVENTIVE MEASURES TO REDUCE AND CONTROL PLASTIC SHRINKAGE

CRACKING IN CONCRETE

AFTER PLACING THE CONCRETE DO NOT ALLOW CONCRETE TO DRY. START CURING AS SOON AS POSSIBLE. > Moisten the formwork and reinforcement before placing the concrete to prevent moisture loss from concrete.

Arrange adequate manpower to place, compact, finish and cure the concrete without any delays.

▸ Protect concrete during any appreciable delay between placing and finishing Float properly after placing the concrete.

Cover with plastic sheet immediately after finishing, or, Start sprinkling / misting concrete surfaces (care must be taken not to use high pressure hose pipe to sprinkle. they may damage the surface/ wash away cement particles). The plastic sheet needs to be held down properly, if this option is chosen.
Pouring concrete

After the concrete is sufficiently stiffened, place wet hessian on the concrete surface and cover it with plastic sheet to keep the hessian wet for longer time. Make arrangements to keep the hessian wet all the time for the entire specified curing period.

Alternatively, pond water and cure continuously for the specified period, or for at least 7 days. > Ensure appropriate and adequate curing under all circumstances.

REFERENCES

1. Non-Structural Cracks in Concrete, Technical Report No. 22, Concrete Society, U.K., Third Ed.. 1992.

2. Causes, Evaluation & Repair of Cracks in Concrete Structures, ACI 224.1R, American Concres Institute.