The physics of diamond

The accurate measurement of the thermal conductivity of metals still poses considerable experimental difficulty. The reasons for this, and the main ways in which the problem has been approached, are summarized. A detailed examination of the development in technique and methods of measurement shows that while most of the steady-state methods introduced over 50 years ago are still being improved, the emphasis in the last few years has been on the development of methods which give more rapid results, particularly at high temperatures.     

Hydrogen-bonded complexes of 1-chloro-2-methylpropan-2-ol with ketones

The interaction of 1-choro-2-methylpropan-2-ol (CMP) with acetone and methyl ethyl ketone was examined in dilute carbon tetrachloride solution. The strengths of the hydrogen-bonded complexes were compared with those of the corresponding complexes of trimethyl carbinol and 1,1,1-trichloro-2-methyl-propan-2-ol with ketones. The aim was to explain the inductive effect of the chlorine atom on the strength of carbinol-ketone hydrogen-bonded complexes. The monomer IR band of CPM appears in solution as a composite of five sub-bands, signifying that many conformers are present; this was confimed by quantum chemical calculations. Chlorine substitution increases the strength of the hydrogen bond.     

Quantum: Einstein,Bohr and the Great Debate About the Nature of Reality,by Manjit Kumar

The history of absolute measurements of gravity is mentioned and the reasons for making absolute measurements are indicated. The principles and main advantages and difficulties of the main method—reversible pendulum, free fall, symmetrical free motion—are discussed and examples of each method are described. Problems of comparison of different determinations and of estimating systematic errors are considered.     

Influence of microwave irradiation on enzyme kinetics

The in vitro effect of 2.45 GHz microwave irradiation on porcine pepsin activity under controlled temperature and absorbed microwave power via kinetic parameters was evaluated. Kinetic study with respect of time of irradiation demonstrated the existence of an inactivation effect of microwaves at pH 2 on pepsin molecule. Bovine serum albumin (BSA)-bromphenol blue (BPB) complex was used as substrate for the assay of pepsin by kinetic method. Depending on absorbed microwave dose, the degree of caused inactivation varies from 39.11 to 45.91% for 5 and 20 min of pepsin MW irradiation, respectively. The V _maxapp and K _mapp were calculated for low (5 min of MW irradiation) and higher specific absorbed dose (20 min of MW irradiation), as well as for untreated enzyme, from double reciprocal Lineweaver-Burk plot. The effect of microwaves on substrate (BSA-BPB complex) was also investigated. For reaction performed with MW irradiated substrate for 5 min the reaction rate was decreased for 15.15%, while for 20 min of substrate irradiation reaction rate was decreased for 25.52% compared to the control reaction. The article is published in the original.     

Dilution reinitiated oscillations in the Bray-Liebhafsky system

The resumption of oscillatory trains in the non-oscillatory region subsequent to completion of the last oscillation, as a phenomenon interesting for the stability of any reaction which can reach the oscillatory state in principle, is analyzed here for the case of the Bray-Liebhafsky reaction. It is shown that this effect is affected by temperature, acidity, initial concentration of hydrogen peroxide and quantity of added water.

---

- , , , . , , , .