UTILIZATION OF SIDOARJO MUD AS THE RAW MATERIAL OF MAKKING PORTLAND CEMENT

Portland cement is generally made of clay, lime, iron sand, silica sand and alumina sand, In this research, the manufacture of cement by using the material in the form of Sidoarjo mud because it has a clay content that resembles that of 2,34% CaO, 6,52% Al2O3, SiO2 Fe2O3 67,63% and 4,88%, making it possible to make an manufacture of Portland cement with addition of CaO and through the combustion process, Research done by mixing mud in Sidoarjo in chalk in some variation ratio of 40:60; 37,5:62,5; 35:65; 32,5:67,5 and 30:70, After a homogeneous mixture and then baked in the furnace at a temperature variation 1200o C with the time allowed is 60, 90, 120, 150 and 180 minutes, Cement is then the compressive strength test and analyzed levels of the chemical, Retrieved best conditions on a comparison between proportion of Sidoarjo mud and lime 30:70, 3 hours burning time and compressive strength value of 13,00 kg / cm2 for ages 3 days and 15,08 kg / cm2 to age 7 days

Thermal degradation of poly(L-lactide): effect of alkali earth metal oxides for selective L,L-lactide formation

To achieve the feed stock recycling of poly(L-lactide) (PLLA) to L,L-lactide, PLLA composites including alkali earth metal oxides, such as calcium oxide (CaO) and magnesium oxide (MgO), were prepared and the effect of such metal oxides on the thermal degradation was investigated from the viewpoint of selective L,L-lactide formation. Metal oxides both lowered the degradation temperature range of PLLA and completely suppressed the production of oligomers other than lactides. CaO markedly lowered the degradation temperature, but caused some racemization of lactide, especially in a temperature range lower than 250 °C. Interestingly, with MgO racemization was avoided even in the lower temperature range. It is considered that the effect of MgO on the racemization is due to the lower basicity of Mg compared to Ca. At temperatures lower than 270 °C, the pyrolysis of PLLA/MgO (5 wt%) composite occurred smoothly causing unzipping depolymerization, resulting in selective L,L-lactide production. A degradation mechanism was discussed based on the results of kinetic analysis. A practical approach for the selective production of L,L-lactide from PLLA is proposed by using the PLLA/MgO composite

Adaptive integral sliding mode control for active vibration absorber design

A new tuning method for active vibration absorber design is presented in this paper. A robust, adaptive control scheme based on a variable structure with an adaptive discontinuity surface is designed and simulated. Robust synthesis of an adaptive discontinuity surface based on an augmented state-space is discussed. The proposed tuning scheme has three superior features compared with the existing counterparts in that: (i) it is completely insensitive to changes in the stiffness and damping of the absorber, (ii) it is capable of suppressing cyclic vibrations over a wide range of frequencies, (iii) its real-time operation requires only one adjustable gain

Non-unitarity and non-reciprocity in scattering from real potentials in presence of confined non-linearity

Investigations of scattering in presence of non-linearity which have just begun require the confinement of both the potential, $V(x)$, and the non-linearity, $\gamma f(|\psi|)$. There could be two options for the confinement. One is the finite support on $x \in [-L,L]$ and the other one is on $x \in [0,L]$. Here, we consider real Hermitian potentials and report a surprising disparate behaviour of these two types of confinements. We prove that in the first option the symmetric potential enjoys reciprocity of both reflectivity ($R$) and transmitivity ($T$) and their unitarity. More interestingly, the asymmetry in $V(x)$ causes non-unitarity ($R+T\ne 1$) and the non-reciprocity (reciprocity) of $T (R)$. On the other hand, the second option of confinement gives rise to an essential non-unitarity even when $V(x)$ is symmetric about a point in $[0,L]$. In the absence of symmetry there occurs non-reciprocity of both $R$ and $T$.Comment: 8 pages, Five Figures each with three parts a.b.

The Relativistic Rotation

The classical rotation is not self-consistent in the framework of the special theory of relativity. the Relativistic rotation is obtained, which takes the relativistic effect into account. It is demonstrated that the angular frequency of classical rotation is only valid in local approximation. The properties of the relativistic rotation and the relativistic transverse Doppler shift are discussed in this work