Building Decision Support Systems in Excel for Production and Distribution Planning: A Case Study

We develop a decision support system in Microsoft Excel that integrates production and distribution for a manufacturer of natural fiber-based products in North America. The production and distribution of the company’s products were optimized using a linear programming model, implemented in Excel. The spreadsheet dynamically adjusts the formulation to reflect the user’s current requirements, solves the optimization model in the background, and generates detailed managerial reports. In addition, it allows users to conduct what-if analyses by varying the number of plants and warehouses. It demonstrates the ability of a Linear Programming Model run on an Excel platform to provide the firm with an optimized production plan resulting in significant, cost savings since implementation

Non Polar and Affinity Monolithic Stationary Phases for Hplc of Large and Small Molecules and Their Use in a Multi Column Liquid Phase Separation Platform for the Capturing and Fractionation of Sialoglycoproteins from Human Serum

Monolithic columns are emerging as important chromatographic separation media. In this investigation, a novel monolithic column was fabricated by the in situ co-polymerization of glyceryl methacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) incorporated with multiwalled carbon nanotubes (MWCNTs). The optimized GMM-EDMA-MWCNTs monolith proved useful for the separation of small molecules including alkyl benzenes, benzene derivatives, anilines and phenoxy acid herbicides. Also, chiral separation of pharmaceutically and environmentally important compounds was achieved on the optimized GMM-EDMA-MWCNTs monolith. When compared to the GMM-EDMA-MWCNTs monolith, the blank GMM/EDMA monolith (i.e., without incorporated MWCNTs) did not yield significant retention toward nonpolar solutes, indicating that the separation on the GMM-EDMA-MWCNTs is solely based on solute differential interactions with the incorporated MWCNTs. However, the GMM-EDMA-MWCNTs monolith was not suitable for separating large molecules such as proteins. In this regards, another novel monolith was prepared by the in situ co-polymerization of octadecyl acrylate (ODA) and trimethloylpropane triacrylate (TRIM) with the intention of separating proteins. The optimized ODA-TRIM monolith proved efficient for separating small molecules (e.g., alkyl benzenes) as well as proteins. The retentive properties of the optimized ODA-TRIM monolith toward small solutes and proteins were further improved by incorporating small amounts of MWCNTs into the ODA-TRIM monolith to yield the optimized ODA-TRIM-MWCNTs monolith. This monolithic was used into a multi column liquid phase separation platform for the capturing and fractionation of sialoglycoproteins from disease free and breast cancer sera. The multi column platform assembled affinity monolithic columns for he depletion of high abundance proteins as well as two lectin monolithic columns specific for sialic acids for the capturing of sialoglycoproteins by lectin affinity chromatography. The two immobilized lectins were Sambucus nigra agglutinin (SNA) and Maakia amurensis lectin (MAL). The sialoglycoproteins captured by the two-lectin columns from human serum were subsequently fractionated online on the optimized ODA-TRIM-MWCNTs monolithic column. The LC-MS/MS analysis of the collected fractions allowed the identification of a panel of differentially expressed sialoglycoproteins in breast cancer serum relative to the disease free serum. This panel of differentially expressed sialoglycoproteins can be considered as a panel of candidate biomarkers for breast cancer.Chemistr

COMPETITIVE STORE CLOSING DURING AN ECONOMIC DOWNTURN: A MATHEMATICAL PROGRAMMING APPROACH

A game theoretic mixed integer program model is introduced to determine optimal store closing decisions in a competitive market. The model considers the case of two rival firms seeking to downsize operations in a region. Both firms are looking to reduce operating costs by closing a number of stores while minimizing demand lost to its rival. We assume a competitive game and apply the model is to find the equilibrium store closing decisions. The model is first applied to a competitive environment for a single period and then incorporated into a solution procedure for a multi period game. The model facilitates the analysis of different strategies that can be used by a retail chain to maximize revenue in depressed market conditions. We find that the profitability is not always the most important factor to consider when determining the number and locations of stores to be closed and that an increase in demand variance will increase the likelihood that an unprofitable store will be kept open for an extended period of time. Our results further indicate that, depending on individual store characteristics it may be optimal to close a profitable store. Our results provide guidelines for developing effective strategies to systematically reduce the number of stores so that net revenue is maximized while competitive pressure is exerted on rival stores

Development of the mechanical engineering complex on the basis of the improvement of large and small businesses relations

Condition, pace and character of the development of the mechanical engineering complex is in many aspects a crucial factor for the social and economic situation of any country. The development of market relations, changes of the conditions of doing business encourage the enterprises to search new managerial methods and to improve the interaction forms. In this respect the display of the peculiarities of the interaction of large machine engineering enterprises and small business in this sphere and also the assessment of the relationship of their development is an important and crucial issue under modern conditions. The most widely spread forms of the cooperation of large scale mechanical engineering enterprises and small businesses of the industry are: outsourcing, franchising, leasing, subcontracting, venture financing, creation of regional forms of the cooperation of large and small firms. However cooperation processes of large scale and small entrepreneurship in Russia are not properly developed. The authors determine the factors hindering the growth of the machine building industry, suggest the recommendations for the development of the large scale enterprises and small business in the industry, substantiate the role of the government in this process. Besides the mechanism of the state support of the development of small business is described

Poly(N-2-(methacryloyloxy)ethyl pyrrolidone)-poly(benzyl methacrylate) diblock copolymer nano-objects via RAFT alcoholic dispersion polymerisation in ethanol

N-2-(methacryloyloxy)ethyl pyrrolidone (NMEP) is a highly polar monomer that is much more readily copolymerised with methacrylic monomers than its structural analogue, N-vinyl pyrrolidone. The RAFT solution polymerisation of NMEP has been conducted in ethanol at 70 °C while varying the degree of polymerisation (DP) from 70 to 400. Reducing the CTA/initiator molar ratio from 10.0 to 3.0 when targeting PNMEP100 led to a three-fold rate enhancement and increased the final monomer conversion from 72% to 98%. Targeting DPs of 200 or greater led to lower monomer conversions. DMF GPC analysis of a series of PNMEPx homopolymers confirmed a linear increase in molecular weight with conversion and relatively low dispersities (Mw/Mn 90%) were obtained and electron microscopy studies indicated that a range of diblock copolymer morphologies, e.g. spheres, worms and vesicles, were produced by polymerisation-induced self-assembly (PISA). Finally, a PNMEP47-PBzMA243 diblock copolymer was synthesised via a convenient 'one-pot' protocol whereby a PNMEP47 macro-CTA was first prepared at 97% conversion, followed by in situ RAFT dispersion polymerisation of BzMA to produce diblock copolymer nano-objects. TEM analysis of aliquots taken during the diblock copolymer synthesis indicated a gradual evolution in copolymer morphology from spherical micelles after 1 h to a pure vesicle phase after 8 h via intermediate mixed phases (including worms)

A triple carboxylic acid-functionalized RAFT agent platform for the elaboration of well-defined telechelic 3-arm star PDMAc

This communication describes the synthesis of a triple acid-functionalized RAFT agent and its use to prepare well-defined 3-arm star polymers of N,N-dimethylacrylamide (DMAc). A simple esterification reaction allowed the convenient integration of three electron-rich naphthalene recognition units on the RAFT agent platform and subsequently the elaboration of a naphthalene end-decorated telechelic 3-arm star PDMAc. This functionalized star polymer was further exploited to build a hydrogel with a complementary homoditopic host unit featuring tetracationic macrocycle cyclobis(paraquat-p-phenylene) units

Effect of the Z- and Macro-R-Group on the thermal desulfurization of polymers synthesized with acid/base "switchable" dithiocarbamate RAFT agents

Thermolysis is examined as a method for complete desulfurization of reversible addition-fragmentation chain transfer (RAFT)-synthesized polymers prepared with acid/base "switchable" N-methyl-N-pyridyldithiocarbamates [RS2 CZ or RS2 CZH+ ]. Macro-RAFT agents from more activated monomers (MAMs) (i.e., styrene (St), N-isopropylacrylamide (NIPAm), and methyl methacrylate (MMA)) with RS2 CZH+ and less activated monomers (LAMs) (i.e., vinyl acetate (VAc) and N-vinylpyrolidone (NVP)) with RS2 CZ are prepared by RAFT polymerization and analyzed by thermogravimetric analysis. In all cases, a mass loss consistent with loss of the end group (ZCS2 H) is observed at temperatures lower than, and largely discrete from, that required for further degradation of the polymer. The temperatures for end group loss and the new end groups formed are strongly dependent on the identity of the R(P)n and the state of the pyridyl Z group; increasing in the series poly(MMA) < poly(St) ∼ poly(NIPAm) << poly(VAc) ∼ poly(NVP) for S2 CZ and poly(MMA) < poly(St) ∼ poly(NIPAm) for S2 CZH+ . Clean end group removal is possible for poly(St) and poly(NVP). For poly(NIPAm), the thiocarbonyl chain end is removed, but the end group identity is less certain. For poly(MMA) and poly(VAc), some degradation of the polymer accompanies end group loss under the conditions used and further refinement of the process is required

Chain transfer kinetics of acid/base switchable n-aryl- n-pyridyl dithiocarbamate RAFT agents in methyl acrylate, n-vinylcarbazole and vinyl acetate polymerization

This is an accepted manuscript of an article published by American Chemistry Society in Macromolecules on 14/05/2012, available online: https://doi.org/10.1021/ma300616g ©American Chemical Society. The accepted version of the publication may differ from the final published version.The structures of the "Z" and "R" substituents of a RAFT agent (Z-C(S)S-R) determine a RAFT agent's ability to control radical polymerization. In this paper we report new acid/base switchable N-aryl-N-pyridyl dithiocarbamates (R = -CH 2CN, Z = -N(Py)(Ar)) which vary in substituent at the 4-position of the aryl ring and the use of these to control molecular weight and dispersity. In their protonated form, the new RAFT agents are more effective in controlling polymerization of the more activated monomer, methyl acrylate (MA), whereas in their neutral form they provide more effective control of the polymerization of less activated monomers, N-vinyl carbazole (NVC) and vinyl acetate (VAc). For each polymerization, the apparent chain transfer coefficient (C trapp) shows a good correlation with Hammett parameters. Dithiocarbamates with more electron-withdrawing aryl ring substituents have the higher C trapp. This demonstrates the influence of polar effects on C trapp and supports the hypothesis that the activity of these RAFT agents is determined by the availability of the lone pair of the dithiocarbamate nitrogen.The authors gratefully acknowledge the Capability Development Fund of CSIRO Materials Science and Engineering for financial support.Published versio

Functionalisation of MWCNTs with poly(lauryl acrylate) polymerised by Cu(0)-mediated and RAFT methods

Poly(lauryl acrylate) P[LA] of various molar masses were prepared via reversible addition–fragmentation chain transfer (RAFT) polymerisation and Cu(0)-mediated radical polymerisation, for the purpose of improving the dispersion and interfacial adhesion of MWCNTs with polymers such as isotactic poly(propylene) (iPP). Lauryl acrylate (LA) was polymerised via RAFT to high conversion (95%), furnished polymers in good agreement with theoretical Mn with dispersity increasing with increasing Mn. LA polymerised via the Cu(0)-mediated method to full conversion (>98%), gave polymers in good agreement with theoretical Mn and low dispersity (Đ ≈ 1.2) for lower molar mass polymers. Low molar mass tailing was also observed for P[LA] via Cu(0)-mediated polymerisation for higher molar mass polymers. Thermogravimetric analysis (TGA) of P[LA] via RAFT showed an onset of degradation occurred at ≈340–350 °C, however, this decreased to ≈250–260 °C for lower molar mass polymers. TGA of the RAFT agent revealed an onset of degradation of ≈200–250 °C. Free radicals generated from thermal degradation of end groups did not influence the thermal stability of the P[LA] backbone and ‘unzipping’ commonly seen with methacrylates was not observed. TGA analysis of P[LA] via the Cu(0)-mediated method revealed a similar degradation profile to that of P[LA] via RAFT. The thermal stability of P[LA] is sufficient to allow for melt processing with iPP. P[LA] via RAFT mixed with MWCNTs showed an adsorption of ≈10–25 wt% P[LA] on to the MWCNTs. The onset of thermal degradation of the P[LA] remained unchanged after adsorption on to the MWCNTs. P[LA] via the Cu(0)-mediated method adsorbed up to 85 wt% and an increase in thermal stability of ≈50 °C was recorded. Increasing P[LA] and MWCNT concentration independently also resulted in an increase in the level of adsorption, possibility due to increased CH–π interaction. The difference in thermal stability could possibly be due to heat transfer from the P[LA] to the MWCNTs, resulting in delayed pyrolysis of P[LA]. Size exclusion chromatography (SEC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) of P[LA] after heating to 200 °C for 30 min in air showed loss of end groups but, the P[LA] backbone remained preserved for both polymer types. Evidence from transmission electron micrographs (TEM) shows the P[LA] adsorbing onto the MWCNT surface. Melt processing composites of P[LA] via Cu(0)-mediated with MWCNTs and iPP was possible as the P[LA] was thermally stable during the both extrusion and in the TGA when studied post melt mixing