Efficient recovering of operation tables of black box groups and rings

People have been studying the following problem: Given a finite set S with a hidden (black box) binary operation * on S which might come from a group law, and suppose you have access to an oracle that you can ask for the operation x*y of single pairs (x,y) you choose. What is the minimal number of queries to the oracle until the whole binary operation is recovered, i.e. you know x*y for all x,y in S? This problem can trivially be solved by using |S|^2 queries to the oracle, so the question arises under which circumstances you can succeed with a significantly smaller number of queries. In this presentation we give a lower bound on the number of queries needed for general binary operations. On the other hand, we present algorithms solving this problem by using |S| queries, provided that * is an abelian group operation. We also investigate black box rings and give lower and upper bounds for the number of queries needed to solve product recovering in this case.Comment: 5 page

Fractionation and valorisation of bark extractives from Eucalyptus species.

Masters Degree. University of KwaZulu-Natal, Durban.The notion of zero-waste in industrial production processes of widely used materials has gained momentum, as industries aim to gain revenue from waste materials which were previously considered as waste. Tree bark from wood obtained from sustainably managed plantations used in the production of timber and pulp industries is an underutilised waste that is mainly used for energy production in mills or left on plantations after debarking. Eucalyptus tree species are commonly used as raw-material in the pulp and paper industry throughout the world. In this thesis, the potential beneficiation of bark from South African planted Eucalyptus tree species (Eucalyptus grandis, Eucalyptus dunnii, Eucalyptus smithii and Eucalyptus nitens) as a source of valuable materials is investigated. Secondary metabolites such as phenolic components, terpenes, steroids and alkaloids can extracted from Eucalyptus bark. In this study, accelerated solvent extraction was investigated for extraction of components in the bark and the components were characterised by a variety of analytical techniques. The investigation was undertaken by optimising the extraction process using the following parameters, temperature (80 to 160℃), number of static extraction cycles (1-3 cycles), solvent type (80% v/v of ethanol or 50% acetone v/v), Eucalyptus species, and particle size (850-500 μm, 500-375 μm and <375 μm). The extraction process was optimised and response surface methodology (RSM) was used to model experimental data for statistical analysis of the Box-Beheknen design of the extraction process. A quadratic model was fitted, and optimum extraction parameters were a temperature of 117℃ with greater than 2 number of static extraction cycles, and bark particles greater than 355 μm. The two target objectives were total phenolic content and total extractive content when using ethanol as the extraction solvent. The amount of phenolic components in the bark extracts was determined by the Folin–Ciocalteu method which using gallic acid as a calibration standard and detection on a UV-vis spectrophotometer. Amongst the four Eucalyptus bark species studied, Eucalyptus dunnii contained the highest amount of phenolic components (5.52g/100g GAE) In addition to using the Folin–Ciocalteu method, the chemical compositions of acetone and ethanol extracts of the bark samples were determined using Pyrolysis-Gas Chromography/Mass Spectrometry. The analysis showed that condensed tannins, with a building block of catechol units, were the most abundant phenolic components present in the bark extracts. Other components that were detected in high amounts were terpenes and terpenoids, and smaller amounts of monoterpenes and sesquiterpenes. Steroid components were also detected, with -sitosterol being the most predominant one. The extractive-free bark samples, remaining after removal of solvent extracts, was analysed using high pressure liquid chromatography to determine their chemical content of cellulose, hemicellulose and lignin

RECOVERING AND UPGRADING KRAFT LIGNIN FOR APPLICATION IN FLEXIBLE POLYURETHANE FOAM

Lignin is the second abundant natural polymer and has been highlighted as a potential substitute for fossil-based raw materials. However, the inherent molecular heterogeneity and the complex recovery processes result in the challenge of controlling the molecular properties and value-added applications of lignin in large scale. To address those issues, a novel acid-liquefaction process was developed in this study to recover Kraft lignin with improved molecular homogeneity directly from black liquor. In the first study, the liquefaction parameters were screened based on yield and molecular weight properties of the recovered lignin. Then, the recovered lignin samples were used to replace 20 wt% of the fossil-based polyols to prepare flexible polyurethane foams. It was found that most of the recovered lignin had improved molecular uniformity (polydispersity (PDI) value \u3c 2) than the traditional acid-precipitated lignin (PDI = 2.2~5.4). Also, the recovered lignin with the Mw value of 1600 Da and the PDI value of 1.8 could maintain the major properties of the flexible PU foams. In the second study, the Box-Behnken response surface methodology (RSM) was employed to investigate the effects of the liquefaction parameters (pH, reaction temperature, and reaction time) on the yield, molecular weights, polydispersity, and quantities of different types of hydroxyl groups of the lignin. Computational models were developed and refined to establish the relationships between the liquefaction parameters and the lignin properties. The yield, molecular weight, and polydispersity of the lignin could be predicted by the optimized models with high R2(pred) values of 87.5-91.5%. An iron-based desulfurization process was developed in third study to remove covalently bonded sulfur in the lignin. The effects of the desulfurization parameters, including reaction temperature, time, and amount of iron, on the sulfur content and desulfurization rate of the lignin were studied. It was found that the highest desulfurization rate was 39.3% at 90 ℃, 16 h, and 0.3 g iron. A life cycle assessment on the lignin production processes and its comparison to the fossil-based polyols were demonstrated in the last study. The lignin produced from the liquefaction process with 140 ℃, pH = 7, and 9 min was more suitable for replacing the fossil-based polyols due to lower CO2 emissions and energy consumptions

The Biosorption of Platinum and Palladium in Chloride Real Leach Solution by Modified Biomass

Modern demands for technological goods have created a global problem of excess electronic wastes (e-wastes). Increasing demands of precious metals to supply factories around the world for these electronic goods may also pose a strain towards current global gold, platinum and palladium reserves. As e-wastes often contain prominent levels of toxic materials along with valuable metals, its recycling must be conducted on an industrial scale to ensure a steady supply of precious metals (PM) for future needs. Current conventional methods of recycling PM including pyrometallurgical and hydrometallurgical processes are often costly, environmentally unfriendly and potentially hazardous. Therefore, researchers have turned towards the study of biomass-based adsorbents, also known as biosorbents, for applications in PM recovery and recycling. In the research presented in the thesis herein, wheat straw, canola meal and wood bark nuggets were used and immobilized with dithiooxamide (DTO), ethylenediamine (EN) and primary amine (PA) to create 12 novel biosorbents. These biosorbents were examined for their effectiveness in recovering platinum (Pt) and palladium (Pd) from real leach solution provided by a PM refining plant in Ontario. From these 12 biosorbents, it was determined that dithiooxamide-immobilized wood bark (DTO-WB) was the most effective. Being able to recover up to 97.4% Pt and 99.8% Pd from diluted leach solution, DTO-WB was selected as the biosorbent of focus for the rest of the research. Characterization analysis including Fourier-Transform Infrared Spectroscopy (FT-IR) and Carbon, Hydrogen, Nitrogen and Sulfur (CHNS) content analysis confirmed that DTO immobilization was successful on the structure of WB. Further experimentation and data analysis revealed that the rate of adsorption of Pt and Pd on DTO-WB progressed via the pseudo-second order rate model. Adsorption isotherm model studies indicate that the adsorption of Pt and Pd by DTO-WB followed the Freundlich and Langmuir adsorption isotherm respectively. Calculated energy levels of activation by Pt and Pd suggests that adsorption progresses due to chemisorption. Thermodynamic studies reveal that DTO-WB adsorption of Pt and Pd is endothermic in nature and that adsorption efficiencies may be improved by increasing operating temperatures. Acknowledging that a variety of dissolved metals exists in real leach solution, performed co-adsorption experiments indicated that DTO-WB was efficient in recovering other PM, namely silver and rhodium. Selenium, a potentially toxic element commonly present in drinking water was also adsorbed in significant numbers by DTO-WB, suggesting that the adsorbent may potentially be used in water-treatment research

Remnants of an ancient metabolism without phosphate

Phosphate is essential for all living systems, serving as a building block of genetic and metabolic machinery. However, it is unclear how phosphate could have assumed these central roles on primordial Earth, given its poor geochemical accessibility. We used systems biology approaches to explore the alternative hypothesis that a protometabolism could have emerged prior to the incorporation of phosphate. Surprisingly, we identified a cryptic phosphate-independent core metabolism producible from simple prebiotic compounds. This network is predicted to support the biosynthesis of a broad category of key biomolecules. Its enrichment for enzymes utilizing iron-sulfur clusters, and the fact that thermodynamic bottlenecks are more readily overcome by thioester rather than phosphate couplings, suggest that this network may constitute a "metabolic fossil" of an early phosphate-free nonenzymatic biochemistry. Our results corroborate and expand previous proposals that a putative thioester-based metabolism could have predated the incorporation of phosphate and an RNA-based genetic system. PAPERCLIP

The Cowl - v.83 - n.10 - Nov 15, 2018

The Cowl - student newspaper of Providence College. Vol 83 - No. 10 - November 15, 2018. 24 pages

Some aspects of the efficient use of multiprocessor control systems

Computer technology, particularly at the circuit level, is fast approaching its physical limitations. As future needs for greater power from computing systems grows, increases in circuit switching speed (and thus instruction speed) will be unable to match these requirements. Greater power can also be obtained by incorporating several processing units into a single system. This ability to increase the performance of a system by the addition of processing units is one of the major advantages of multiprocessor systems. Four major characteristics of multiprocessor systems have been identified (28) which demonstrate their advantage. These are:- Throughput Flexibility Availability Reliability The additional throughput obtained from a multiprocessor has been mentioned above.. This increase in the power of the system can be obtained in a modular fashion with extra processors being added as greater processing needs arise. The addition of extra processors also has (in general) the desirable advantage of giving a smoother cost - performance curve ( 63). Flexibility is obtained from the increased ability to construct a system matching the user 'requirements at a given time without placing restrictions upon future expansion. With multiprocessor systems; the potential also exists of making greater use of the resources within the system. Availability and reliability are inter-related. Increased availability is achieved, in a well designed system, by ensuring that processing capabilities can be provided to the user even if one (or more) of the processing units has failed. The service provided, however, will probably be degraded due to the reduction in processing capacity. Increased reliability is obtained by the ability of the processing units to compensate for the failure of one of their number. This recovery may involve complex software checks and a consequent decrease in available power even when all the units are functioning

Literature review of physical and chemical pretreatment processes for lignocellulosic biomass

Different pretreatment technologies published in public literature are described in terms of the mechanisms involved, advantages and disadvantages, and economic assessment. Pretreatment technologies for lignocellulosic biomass include biological, mechanical, chemical methods and various combinations thereof. The choice of the optimum pretreatment process depends very much on the objective of the biomass pretreatment, its economic assessment and environmental impact. Only a small number of pretreatment methods has been reported as being potentially cost-effective thus far. These include steam explosion, liquid hot water, concentrated acid hydrolysis and dilute acid pretreatments

Consumer Cooperatives: An Alternative Institutional Model for Delivery of Urban Water Supply and Sanitation Services?

This paper describes the essential characteristics of consumer cooperatives engaged in the provision of basic services and discusses their applicability as a model for water supply and sanitation service provision in urban areas. A cooperative is an autonomous association of persons united voluntarily to meet their common economic, social, and cultural needs and aspirations through a jointly-owned and democratically-controlled enterprise. The paper focuses on system-wide urban water supply cooperatives and it is thus not concerned with urban or peri-urban cooperatives that depend on either boreholes or bulk purchases of water from a utility for distribution, nor does it refer to rural water supply cooperatives that are generally small. After a general overview of cooperatives and a discussion of the main characteristics of utility cooperatives, the paper reviews the case of SAGUAPAC, a successful urban WSS cooperative in Bolivia, from which it draws some conclusions in the form of a preliminary assessment of cooperatives as a model for delivery of urban water supply and sanitation (WSS) services

Quantum Algorithms For: Quantum Phase Estimation, Approximation Of The Tutte Polynomial And Black-box Structures

In this dissertation, we investigate three different problems in the field of Quantum computation. First, we discuss the quantum complexity of evaluating the Tutte polynomial of a planar graph. Furthermore, we devise a new quantum algorithm for approximating the phase of a unitary matrix. Finally, we provide quantum tools that can be utilized to extract the structure of black-box modules and algebras. While quantum phase estimation (QPE) is at the core of many quantum algorithms known to date, its physical implementation (algorithms based on quantum Fourier transform (QFT) ) is highly constrained by the requirement of high-precision controlled phase shift operators, which remain difficult to realize. In the second part of this dissertation, we introduce an alternative approach to approximately implement QPE with arbitrary constantprecision controlled phase shift operators. The new quantum algorithm bridges the gap between QPE algorithms based on QFT and Kitaev’s original approach. For approximating the eigenphase precise to the nth bit, Kitaev’s original approach does not require any controlled phase shift operator. In contrast, QPE algorithms based on QFT or approximate QFT require controlled phase shift operators with precision of at least Pi/2n. The new approach fills the gap and requires only arbitrary constant-precision controlled phase shift operators. From a physical implementation viewpoint, the new algorithm outperforms Kitaev’s approach. iii The other problem we investigate relates to approximating the Tutte polynomial. We show that the problem of approximately evaluating the Tutte polynomial of triangular graphs at the points (q, 1/q) of the Tutte plane is BQP-complete for (most) roots of unity q. We also consider circular graphs and show that the problem of approximately evaluating the Tutte polynomial of these graphs at the point (e 2πi/5 ,e−2πi/5 ) is DQC1-complete and at points (q k , 1 + 1−q−k (q 1/2−q−1/2) 2 ) for some integer k is in BQP. To show that these problems can be solved by a quantum computer, we rely on the relation of the Tutte polynomial of a planar G graph with the Jones and HOMFLY polynomial of the alternating link D(G) given by the medial graph of G. In the case of our graphs the corresponding links are equal to the plat and trace closures of braids. It is known how to evaluate the Jones and HOMFLY polynomial for closures of braids. To establish the hardness results, we use the property that the images of the generators of the braid group under the irreducible Jones-Wenzl representations of the Hecke algebra have finite order. We show that for each braid b we can efficiently construct a braid ˜b such that the evaluation of the Jones and HOMFLY polynomials of their closures at a fixed root of unity leads to the same value and that the closures of ˜b are alternating links. The final part of the dissertation focuses on finding the structure of a black-box module or algebra. Suppose we are given black-box access to a finite module M or algebra over a finite ring R, and a list of generators for M and R. We show how to find a linear basis and structure constants for M in quantum poly(log |M|) time. This generalizes a recent quantum algorithm of Arvind et al. which finds a basis representation for rings. We then show that iv our algorithm is a useful primitive allowing quantum computers to determine the structure of a finite associative algebra as a direct sum of simple algebras. Moreover, it solves a wide variety of problems regarding finite modules and rings. Although our quantum algorithm is based on Abelian Fourier transforms, it solves problems regarding the multiplicative structure of modules and algebras, which need not be commutative. Examples include finding the intersection and quotient of two modules, finding the additive and multiplicative identities in a module, computing the order of an module, solving linear equations over modules, deciding whether an ideal is maximal, finding annihilators, and testing the injectivity and surjectivity of ring homomorphisms. These problems appear to be exponentially hard classically