Proportional-integral-plus control applications of state-dependent parameter models

This paper considers proportional-integral-plus (PIP) control of non-linear systems defined by state-dependent parameter models, with particular emphasis on three practical demonstrators: a microclimate test chamber, a 1/5th-scale laboratory representation of an intelligent excavator, and a full-scale (commercial) vibrolance system used for ground improvement on a construction site. In each case, the system is represented using a quasi-linear state-dependent parameter (SDP) model structure, in which the parameters are functionally dependent on other variables in the system. The approach yields novel SDP-PIP control algorithms with improved performance and robustness in comparison with conventional linear PIP control. In particular, the new approach better handles the large disturbances and other non-linearities typical in the application areas considered

WELL DELIVERABILITY PREDICTIONS OF GAS FLOW IN GAS-CONDENSATE RESERVOIRS, MODELLING NEAR-CRITICAL WELLBORE PROBLEM OF TWO PHASE FLOW IN 1 -DIMENSION

Production of gases from gas-condensate reservoirs are known to bear certain challenges largely due to the formation of retrograde condensates that hinder gas flow. The drop out of this liquid creates flow regions that are characterized by the liquid saturation as it affects the mobility of the two phase flow, thereby preventing the effective modeling of well productivity. In this study, a predictive model based on an analytical approach is developed to predict gas flow in gas condensate reservoirs. This study compares the estimated gas flow from the developed model for gas-condensate reservoirs to the flow of an existing model for gas reservoirs. This study observes the effects of liquid drop-out on productivity at low pressures and the condensate unloading pressure, which is comparable to that of commercial softwar

Direct digital control of an efficient silicon+lequid crystal phase shifter

We demonstrate a phase shifter based on a silicon slot waveguide infiltrated with liquid crystal. We achieve a phase shift of 73 pi for a 5V drive voltage, with a voltage-length product of 0.022V.mm around 1V. We can drive the phase shifter directly with a 1V, duobinary pulse-width-modulated signal, allowing direct digital CMOS control of an analog optical phase shifter

Antibiotic resistance profile of staphylococci from clinical sources recovered from infants

Infants, children and the aged are among the groups most vulnerable to microbial infections more so when these microbial agents become resistant to antimicrobials. The antibiotic resistant profile of Staphylococcus aureus and selected coagulase negative staphylococci were determined by standard methods. Of the 178 staphylococcal isolates evaluated, 122 were S. aureus and the rest coagulase negative staphylococci. 68% of S. aureus isolates were resistant to amoxicillin, 69.8% to cloxacillin, 51% to augmentin and 71% to tetracycline. However, only 2.6% of the 116 S aureus isolates tested were resistant to gentamycin making the drug a reliable therapeutic agent in the event of failure of other antimicrobials in treating staphylococcal infections at least in this community. Resistance to the penicillin drugs was mediated by the elaboration of &#946-lactamase by both pathogenic and non-pathogenic staphylococci. The study shows a high rate of cloxacillin resistance and possibly the existence of methicillin resistance among these strains. 80% of the S aureus strains were multi-resistant with 25% of these resistant to three different antibiotics, 21% to 4 and 6.8% to 6 different drugs. Only 1.2% of these S aureus strains were resistant to 7 different antimicrobials underscoring the need to reduce the high incidence of multi-resistance in this community in the event of an epidemic caused by these strains. The study reveals prevalence of multi-resistance among both pathogenic and non-pathogenic staphylococci in the community.Key words: Staphylococci, Staphylococcus aureus, antibiotics, multi-resistance.African Journal of Biotechnology Vol. 4 (8), pp. 810-82

Assisted Self-Assembly to Target Heterometallic Mn-Nd and Mn-Sm SMMs: Synthesis and Magnetic Characterisation of [Mn7_{7}Ln3_{3}(O)4_{4}(OH)4_{4}(mdea)3_{3}(piv)9_{9}(NO3_{3})3_{3}] (Ln=Nd, Sm, Eu, Gd)**

Assisted self-assembly by using a preformed [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] (1) (pivH=pivalic acid) cluster leads to 3 different outcomes of the reaction with Ln(NO$_{3}$)$_{3}$ ⋅ xH$_{2}$O (Ln=Pr−Ho and Y): Mn$_{7}$Ln$_{3}$ and in some cases the inverse butterfly Mn$_{2}$Ln$_{2}$ for Ln=Pr−Eu, Mn$_{5}$Ln$_{4}$ for Ln=Tb-Ho and in the special case of Gd all three possibilities can form. Whilst the magnetic properties for the Mn$_{5}$Ln$_{4}$ systems show the expected known SMM properties, for Mn$_{7}$Ln$_{3}$ two new examples of Nd- and Sm-containing SMMs have been discovered. in an assisted self-assembly approach starting from the [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] cluster a family of Mn−Ln compounds (Ln=Pr−Yb) was synthesised. The reaction of [Mn$_{6}$O$_{2}$(piv)$_{10}$(4-Me-py)$_{2}$(pivH)$_{2}$] (1) with N-methyldiethanolamine (mdeaH$_{2}$) and Ln(NO$_{3}$)$_{3}$ ⋅ 6H$_{2}$O in MeCN generally yields two main structure types: for Ln=Tb−Yb a previously reported Mn$_{5}$Ln$_{4}$ motif is obtained, whereas for Ln=Pr−Eu a series of Mn$_{7}$Ln$_{3}$ clusters is obtained. Within this series the Gd$^{III}$ analogue represents a special case because it shows both structural types as well as a third Mn$_{2}$Ln$_{2}$ inverse butterfly motif. Variation in reaction conditions allows access to different structure types across the whole series. This prompts further studies into the reaction mechanism of this cluster assisted self-assembly approach. For the Mn$_{7}$Ln$_{3}$ analogues reported here variable-temperature magnetic susceptibility measurements suggest that antiferromagnetic interactions between the spin carriers are dominant. Compounds incorporating Ln=Nd$^{III}$(2), Sm$^{III}$(3) and Gd$^{III}$ (5) display SMM behaviour. The slow relaxation of the magnetisation for these compounds was confirmed by ac measurements above 1.8 K

KARAKTERISTIK EDIBLE FILM BERBAHAN WHEY DAN KASEIN YANG MENGGUNAKAN JENIS PLASTICIZER BERBEDA (Characteristics of Edible Film Made from Whey Dangke and Casein that uses different types of Plasticizer)

The combination of materials from dangke whey and casein can form an edible flm. The addition of a plasticizer such as glycerol, sorbitol and polyethylene glycol (PEG), in the manufacture of the edible flm can improve the characteristics of the edible flm becoming elastic, fexible and not easily fragile. The purpose of this research was to study the effect of plasticizer glycerol, sorbitol and polyethylene glycol (PEG) to the edible flm characteristics such as thickness, yield, and color (* L, * a and * b). This study was run according to completely randomized design with plasticizer types as the treatment consisted of glycerol, sorbitol, and polyethylene glycol (PEG) with a concentration of 35%. Each treatment was repeated 5 times. The results obtained indicated that the type of plasticizer did not affect the thickness of the edible flm. The yield of edible flm was 26.45 ± 0.34%, 24.53 ± 0.29%, and 22.56 ± 0.30% for glycerol, PEG, and sorbitol, respectively. The color value (*L) of edible flm was 88.40 ± 0.33 for sorbitol, 87.28 ± 0.25 for PEG, and 88.40 ± 0.33 for glycerol. The color value (*a) was 5.97 ± 0.10, 3.86 ± 0.13, and 0.09 ± 0.02, for glycerol, PEG, and sorbitol, respectively. While the color value (*b) of edible flm was 4.36 ± 0.10 for PEG, 1.32 ± 0.36 for sorbitol, and 1.10 ± 0.13 for glycerol. It was concluded that the use of sorbitol would increase brightness (*L) and the yield of edible flm. The use of glycerol has an efect on the reddish color of the edible flm (*a), while the PEG increase the yellowish color of the edible flm (*b)

Classical Analysis of Phenomenological Potentials for Metallic Clusters

The classical trajectories of single particle motion in a Wodds-Saxon and a modified Nilsson potential are studied for axial quadrupole deformation. Both cases give rise to chaotic behaviour when the deformation in the Woods-Saxon and the l**2 term in the modified Nilsson potential are turned on. Important similarities, in particular with regard to the shortest periodic orbits, have been found.Comment: 9 pages LaTex + 4 figures available via e-mail requests from the authors, to appear in Phys.Rev.Let

Keragaman dan Kebutuhan Teknologi Pakan Peternak Sapi Perah di Kabupaten Enrekang

An appropriate understanding towards preference of small-scale dairy producers can improve technology adoption. The objective of this study was to understand potential, problem and need of small-scale dairy producers including farmer and his wife. The method used was modification of participatory rural appraisal (PRA) like participatory mapping to detect potential, and Preference ranking to understand problem and need priority. PRA applications were six times during April-September 2009 at central area and non-central area in Enrekang regency. Preference of farmer and his wife toward potential and problem were not different. Only feed technology need was different. Forage sources at central area were more diverse than non-central area but concentrate sources at non-central area were more than central area. Lack of knowledge for feed and concentrate formulation and nutritional requirements, less known of feed use, and low feed quality at dry season were the main problems at central area. At non-central area, lack of knowledge for preserving feed, lack of labour, and feed shortage at dry season were main problem faced by farmers. Knowledge improvement for local feed and complete-feed formulation are priority technology at central area. At non-central area, agricultural waste and forage preserving and complete-feed are needed by farmer

Evaluating the Moisture Content Variation on Critical Strain of Geo-materials: A Case Study

The tunnel's stability during construction is a very important matter. Some methods have been proposed for stability evaluation, but the hazard warning levels (HWLs) are more applicable among these methods. Despite monitoring and applying HWLs, several collapses in Shibli twin tunnels in Iran have cast doubts on the accuracy of this criterion in the presence of water. In this study, the critical strains under different water contents were measured through uniaxial compressive strength tests on 11 different shale and marl samples. A comparison of laboratory tests and numerical results shows that the influence of the moisture content on the critical strain is negligible. In addition, the results show that there is no direct relationship between the critical strain and uniaxial compression strength