The composition of volatile extractives from the wood of Juniperus excelsa, Juniperus foetidissima and Juniperus oxycedrus

J. excelsa , J. foetidissima and J. oxycedrus. Among the compounds the monoterpenes exist in minor amounts while the sesquiterpenes including their oxygenated members as well as sesquiterpene alcohols consist of the majority of the whole substances. The existence of some compounds of the oils might be attributes of the species and their sap- and heartwood. On the other side though notable differences, the essential oils of Turkish juniper woods resemble the commercial cedar wood oils.

---

Die Zusammensetzung der flüchtigen Extraktstoffe im Holz von Juniperus foetidissima und Juniperus oxycedrus

J. excelsa , J. foetidissima und J. oxycedrus. Monoterpene bilden einen geringen Anteil der Extraktstoffe. Der Hauptteil besteht aus Sesquiterpenen mit deren Oxydationsprodukten. Das Vorkommen einiger der ?le k?nnte charakteristisch sein für die jeweilige Art bzw. deren Splint- und Kernholz Allerdings gleichen diese ?le, trotz geringer Unterschiede, den wesentlichen ?lbestandteilen von Kommerziellen Zedernh?lzern.

---

---

This work was supported by the research found of the Istanbul University. Project nr: 1335/280799.     

Shortest path algorithms: A computational study with the C programming language

The main purpose of this study is to evaluate the computational efficiency of algorithms for calculating shortest paths when they are correctly coded by using the C programming language. The eight algorithms that we selected for this experiment are the most efficient, either measured in terms of worst-case bounds or marked as such from previous computational studies; they include the redistributive heap algorithm. We suggest computer implementations that use the full power of C. In particular, the network representation and the various data structures used to keep the scan eligible list may be managed by using only additions and no multiplications, while it is not possible with FORTRAN. These capabilities, unique to C, yield several interesting conclusions: one may expect to speed up a shortest path algorithm by a factor of 20%; in some cases, this factor may reach 30%. Interestingly, the level of programming difficulty required to achieve these benefits is not greater than that required by implementations using arrays.     

Robustness assessment via stability radii in delay parameters

This paper focuses on the robust stability analysis of a class of linear systems including multiple delays subjected to constant or time‐varying perturbations. The approach considered makes use of appropriate stability radius concepts (dynamic, static) and relies on a feedback interconnection interpretation of the uncertain system. Various computable bounds on stability radii are obtained that exploit the structure of the problem. Systems including perturbations on both system matrices and delays are also dealt with. Copyright © 2008 John Wiley & Sons, Ltd.     

Robust regression for high throughput drug screening

Effective analysis of high throughput screening (HTS) data requires automation of dose-response curve fitting for large numbers of datasets. Datasets with outliers are not handled well by standard non-linear least squares methods, and manual outlier removal after visual inspection is tedious and potentially biased. We propose robust non-linear regression via M-estimation as a statistical technique for automated implementation. The approach of finding M-estimates by Iteratively Reweighted Least Squares (IRLS) and the resulting optimization problem are described. Initial parameter estimates for iterative methods are important, so self-starting methods for our model are presented. We outline the software implementation, done in Matlab and deployed as an Excel application via the Matlab Excel Builder Toolkit. Results of M-estimation are compared with least squares estimates before and after manual editing.     

Lower and upper bounds for the two-echelon capacitated location-routing problem

In this paper, we introduce two algorithms to address the two-echelon capacitated location-routing problem (2E-CLRP). We introduce a branch-and-cut algorithm based on the solution of a new two-index vehicle-flow formulation, which is strengthened with several families of valid inequalities. We also propose an adaptive large-neighbourhood search (ALNS) meta-heuristic with the objective of finding good-quality solutions quickly. The computational results on a large set of instances from the literature show that the ALNS outperforms existing heuristics. Furthermore, the branch-and-cut method provides tight lower bounds and is able to solve small- and medium-size instances to optimality within reasonable computing times.     

Buried ordnance detection: electromagnetic modeling of munition-mounted radio frequency identification tags

In order to improve means for locating unexploded ordnance items (UXO) and significantly discriminating UXO from clutter, it is desired to tag ordnance items before they are delivered. The munition tagging envisioned will make use of current passive radio frequency identification (RFID) tag technology. The tags will provide information on the munition's location and identity when the UXO tag interrogation module is brought nearby. Knowledge of the magnetic field's behavior is essential in understanding the designs required to transmit energy from the above-ground interrogator to the tag and from the tag back to the above-ground receiver. The munition, being a large metal structure in such close proximity to the tags, will affect their operation because of electromagnetic boundary conditions and the tags' specific circuitry. To this end, modeling of the magnetic fields was required. This paper presents the results of this modeling effort and includes experimental findings. The modeling efforts demonstrated that detection depths to 1 m would be achievable, provided the system is magnetically optimized.     

A study on helical surface generated by the primary peripheral surfaces of ring tool

Often in the engineering practice, cutting tools bounded by primary peripheral surfaces of revolution are used because of their effectiveness. Among these, ring and tangential tools can be used for the generation of constant pitch cylindrical helical surfaces. In this paper, we present an algorithm for the profiling of these types of tools. The algorithm is based on the topological representation of the tool’s primary peripheral surface. The main goal is to devise a methodology for the profiling of tools whose surfaces are reciprocally enveloping with cylindrical helical surfaces. We present a numerical example for the numerical determination of the axial section form for this type of tools. The application method for this algorithm was developed in the CATIA graphical design environment within which the procedure is developed as a vertical application. In addition, we present a solution for the shape correction of the tool’s axial cross-section by considering the existence of singular points on the profile of the helical surface to be generated where multiple normals to the surface exist.     

Covalently-Bonded “Onion Type” Double Fullerenic Carbon Cages

Abstract

Three “onion type” double carbon cages (consisting of an inner sp³-hybridized C₆₀ buckminsterfullerene skeleton and an outer larger carbon cage with icosahedral symmetry, with covalent bonds between the carbon atoms of the 5-membered rings) are described and their strain energies are discussed: (i) when the outer cage is a C₁₂₀ cage derived from buckminsterfullerene by replacing each bond between two six-membered rings by an acetylenic group, the strain is smallest.; (ii) when the same derivation concerns each bond between 5- and 6-membered rings leading to a C₁₈₀ outer cage, the strain is largest.; (iii) when the outer cage is C₁₈₀ with benzenoid rings, the strain is intermediate.