Experimental investigation on the friction characteristics of hazelnut powder reinforced brake pad

After the realization that asbestos fiber is harmful to human health, efforts to produce organic and environmentally friendly brake pads have increased. In this study, an environmentally friendly brake pad (NUS sample) was produced with the addition of 3.5% hazelnut shell powder. Hardness and density measurements of the brake pad sample were made. Chase type device was used for the wear and friction tests. The experiments were done according to the SAE J661 standard. The average friction coefficient value obtained as a result of the experiments was found to be 0.435 µ. Bu değer standartlara uygundur ve “FF” sınıfı aralığındadır. This value complies with the standards and is in the "FF" class range.

Low-frequency Flux Density Measurements and Pulsars with GHz-peaked Spectra

We have estimated flux densities of several pulsars from radio interferometric observations mainly at 325 MHz using the Giant Metrewave Radio Telescope. The new observations allowed us to update the spectral nature of the observed pulsars, and in six sources we identified relatively high frequency turnovers, which can be classified as new GHz-peaked spectrum (GPS) pulsars. For such objects the turnover in the spectrum is most likely caused by absorption in the immediate vicinity of the pulsar (or in the interstellar medium). We modeled the turnover spectra using the thermal free–free absorption model and the physical parameters obtained from the fits enabled us to identify the environments that could potentially be responsible for the observed absorption, such as pulsar wind nebulae, supernova remnant nebulae or H ii regions. The discovery of 6 new GPS pulsars brings the total number of such objects to 33 and we discuss the properties of the entire sample.