A simple laboratory method using the universal testing machine, to compare the rolling resistance values of tyres of different design has been developed using the concept of single loop hysteretic energy loss e(h). The e(h) value is calculated from the loop area enclosed between the loading/unloading curves as the tyre footprint goes through one compression / relaxation cycle. The e(h) values for a number of P195/75R14 and P225/60R16 size tyres of different design from two manufacturers were obtained. Individual e(h) values as well as e(h) ratio of tyre pairs of different design showed one to one correspondence with the respective R and R ratio values. These results indicated that the e(h) could be considered a measure of R. The directional change in e(h) with design variation agreed with the directional change in R. This simple test method, rather than the conventional one using heavy duty test machine, is helpful for preliminary comparison of rolling loss values of tyres of different designs. 

Nanosilica prepared by acid hydrolysis of sodium silicate under controlled conditions was used as additional filler and as a component of the HRH dry bonding system in short nylon 6 fibre-elastomer composites based on natural rubber (NR), acrylonitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR). Their thermal degradation was studied by thermogravimetric analysis (TGA). The kinetics of the degradation was analysed using Freeman-­Caroll equation. The short nylon fibre improved the thermal properties of the composites based on NR, SBR, and NBR. The introduction of nanosilica improved the thermal stability of the composites better than commercial silica. The onset temperature (Ti) of degradation of NBR and SBR based composites was almost in the same range. NR composites showed a lower Ti value. Among the three types of elastomeric composites NR based composites showed the lowest peak degradation temperature (Tmax). All the composites showed two-step degradation process. In the case of NR composites the first degradation peak corresponds to the degradation of natural rubber and the second to the degradation of the nylon fibre. Studies showed that the degradation of all the three elastomeric composites followed the first-order kinetics. 

Pruning of above-ground biomass could result in cessation of root growth or partial death of the root system. This study determines the impact of stock shoot cut-back on root and shoot growth of rubber plants (Hevea brasiliensis Muell. Arg.) raised in polybags. Low and high vigor plants were either cut-back or not after successful grafting. Seedling or scion diameter and root lengths were measured at 2-week intervals thereafter. Shoot and root growth were significantly higher in high vigor plants than those in low vigor plants. There was a decrease in feeder and lateral root lengths of plants by 4-6 weeks after cut-back (by 60% and 40%, respectively), which could be attributed to the lack of carbohydrate supply. These increased thereafter with the supply of carbohydrates from the new scion. The root system of non cut-back plants grew uninterruptedly. These effects were not dependant on plant vigor. Feeder roor growth was more compared to lateral root growth during 6-12 weeks after cut-back. As the six weeks following cut-back appears to be a critical period for rubber plants raised in polybags due to very low root activity adequate care should be taken to protect the plants at that stage from adverse environmental conditions. 

The study focused on the credit demand among rubber small-holders in Edo state, Nigeria using a probit model. The data was obtained from a sample survey of 100 rubber small-holders in the study area using a multi-stage random sampling method. Both descriptive statistics and probit model were used to analyze the data. The study indicated that 57 per cent of the selected farmers source credit from non-formal financial institutions such as money lenders, friends and relatives. The probir model was used to determine the factors influencing the probability that a farmer would demand for credit in the study area. The model revealed that the influence of factors such as farmers' experience, level of education and amount spent on farming inputs were highly significant. 

Degradation behaviour of natural rubber (NR) and its 50/50 blends with four synthetic rubbers viz., hydrogenated nitrile rubber (HNBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR) and acrylonitrile butadiene rubber (NBR) were evaluated with respect to heat, oil, ozone and radiation as NR degrades very easily under these conditions. All the blends exhibited better ageing resistance than pure NR. Among the blends, NR/HNBR showed remarkable degradation resistance under all the conditions. Though NR/EPDM exhibited better heat and ozone resistance, its oil ageing resistance was very poor and had only very low initial tensile properties. NR/NBR showed excellent oil, ageing and radiation resistance, but its heat and ozone resistance were very poor. NR/CR showed lower degradation resistance than pure NR. 

A detailed investigation on various structural traits of bark and their influence on the inclination and orientation of laticifers in Hevea brasiliensis was attempted in ten clones, viz., Tjir 1, Gl 1, GT 1, PB 86, PB 28/59, PB 235, RRIM 600, RRIM 703, RRII 105 and RRII 300 at the age of 17-21 years. The inclination of laticifers in seedling progenies of two Wickham x Amazon cross combinations (RRII 105 x MT 1005 and RRIM 600 x AC 495) and bud grafted plants of RRII 105 and RRIM 600 was also studied at the age of 4 years to understand the pattern of inclination during the immature growth phase.
The present investigation revealed significant clonal variation in the angle of inclination of laticifers and phloic rays. The clones RRIM 703, Gl 1, RRII 300, Tjir 1, PB 235 and GT 1 showed laticifers inclined towards the right and the clone PB 86 towards the left direction. Three clones, PB 28/59, RRIM 600 and RRII 105, showed the laticifer inclination towards both left and right directions. The young budded plants of RRII 105 showed rightward inclination whereas the laticifers of the clone RRIM 600 showed both rightward and leftward inclination. The seedling progenies of both cross combinations showed rightward inclination. Correlation and regression analyses conclusively proved that various anatomical characters showed positive or negative associations with laticifer inclination. The inclination of phloic rays was identified as the most important factor which shows positive influence on inclination of laticifers. The inclination of laticifers in H brasiliensis can be considered as a clone - specific character and has great significance on the direction and angle of tapping cut to be adopted for optimisation of potential yield of different clones.