The impact of alum coagulation on the character, biodegradability and disinfection by-product formation potential of reservoir natural organic matter (NOM) fractions

Natural Organic Matter (NOM) from Myponga Reservoir, South Australia, was separated into four organic fractions based on their hydrophobic and hydrophilic properties using a sequence of non-ionic and ionic resins. NOM fractions were isolated for the purpose of determining the impact of alum coagulation on removal of these fractions in conventional water treatment, and their potential as precursors in the formation of disinfection by-products (DBP) and in supporting microbial growth. The NOM comprised VHA (very hydrophobic acids), SHA (slightly hydrophobic acids), CHA (charged hydrophilics) and NEU (neutral hydrophilics) fractions. These fractions were then jar tested with alum using low (50 mg/L), operational (100 mg/L) and very high (200 mg/L) doses to assess the removal capacities for these fractions in a conventional treatment plant. High-performance size exclusion chromatography-UV-DOC (HPSEC-UV-DOC) revealed that alum removed more of the hydrophobic and higher molecular weight components of NOM, but less of the NEU fraction and lower molecular weight components of NOM. Determination of biodegradable dissolved organic carbon (BDOC) indicated that the NEU fraction had the highest biodegradability, followed by the CHA, SHA and VHA fractions. The VHA fraction had the highest total-trihalomethane formation potential (t-THMFP), followed by NEU, SHA and CHA. The NOM not removed by alum coagulation had the potential to support microbial growth (NEU fraction), and disinfection by-product (DBP) formation (VHA and NEU fractions). To obtain treated water with lower overall residual NOM, other treatment methods would need to be applied in addition to alum coagulation in order to reduce the concentration of the neutral fraction.     

Strict positive realness of a family of polytopic plants

Some strict positive realness results for a family of polytopic plants are presented. More specifically, it is shown that the strict positive real property of such a family of plants can be ascertained from its vertex plants     

Simplified Iterative MMSE Multiuser Detector Using Polynomial-Expansion Approximation

We propose to simplify the inverse matrix computation of the iterative MMSE multiuser detector by using a low-complexity polynomial-expansion matrix approximation. This approximation is an application of the polynomial-expansion multiuser detector. The number of stages is set to the number of users to obtain a linear complexity. Simulations under AWGN and asynchronous multipath channels show that the approximation performs as well as the exact inverse implementation for iterative MMSE multiuser detector.     

Hardware fault latency: Problem formulation and solution

A fault does not necessarily cause an immediately effective error, thereby leading to a system failure. Many experiments have shown that most hardware faults do not cause immediately detectable errors. In fact, it has been found that a significant proportion of the faults injected during the experiments remained latent, i.e. went undetected. In this paper we call this phenomenon the latency problem. An analytical model is developed in the paper to study the effects of the latency problem on fault-tolerant computer systems. Some of the results of our sensitivity analysis are presented and discussed.     

A general stability theorem for linear discrete-time systems

The strongest sufficient conditions for constraining zeros to be on or within a circular region in thezplane in terms of weighted absolute norms are derived using elementary geometry. It is shown that the weighted L1norm yields the strongest result.     

Identification for systems with bounded noise

In this paper, we present a set-membership identification algorithm for systems with unknown but bounded disturbance. The algorithm contains a weighting factor which is selected according to whether the new observed data contains sufficient information. The proposed approach ensures that the estimation error is bounded and nonincreasing. Furthermore, it is shown that the parameter estimates provided by the algorithm will converge to a region containing the true parameters, and its upper bound is also given     

Reconstruction of moderate sized intra-oral defects using the nasolabial flap

The nasolabial flap was used in 11 patients for reconstruction of moderate sized intra-oral defects. There was minimal morbidity of donor and recipient sites in terms of function and cosmesis. The flap was easily harvested, with a reduction in operating time. The superb vascularity and reliability of the flap was demonstrated by the fact that it was possible to use this flap even after a radical neck dissection had been performed on the same side or after radiotherapy. This article describes the authors' experience with the use of the subcutaneously-pedicled, inferiorly-based, double-staged nasolabial flap for intra-oral reconstruction.     

Improved lower bounds on the reliability of hypercube architectures

The hypercube topology, also known as the Boolean n-cube, has recently been used for multiprocessing systems. The paper considers two structural-reliability models, namely, terminal reliability (TR) and network reliability (NR), for the hypercube. Terminal (network) reliability is defined as the probability that there exists a working path connecting two (all) nodes. There are no known polynomial time algorithms for exact computation of TR or NR for the hypercube. Thus, lower-bound computation is a better alternative, because it is more efficient computationally, and the system will be at least as reliable as the bound. The paper presents algorithms to compute lower bounds on TR and NR for the hypercube considering node and/or link failures. These algorithms provide tighter bounds for both TR and NR than known results and run in time polynomial in the cube dimension n, specifically, within time O(n²)