The Used of the Internet in Procurement: An Empirical Analysis

According to a recent survey, 16% of all Swiss companies use an e-commerce solution to sell their products [15]. On the other hand, most companies in Switzerland are unfamiliar with the use of the Internet for purchasing and procurement processes and especially for online buying. This paper discusses the new requirements for procurement and shows the new concepts and strategies that have recently been developed. The main focus is on the opportunities and benefits of new information and communication technologies, especially the Internet. Included in this study are the results of an empirical survey conducted in Switzerland in October 1999. The aim of the survey was to analyze to what extent the Internet is being used in procurement of Swiss companies with more than 100 employees. The results show that the take-up of the opportunities and benefits of the Internet is currently rather low and that most Swiss companies seem to be satisfied with the efficiency of their procurement processes

Dispersion and Reinforcing Potential of Carboxymethylated Nanofibrillated Cellulose Powders Modified with 1-Hexanol in Extruded Poly(Lactic Acid) (PLA) Composites

Bionanocomposites of poly(lactic acid) (PLA) and chemically modified, nanofibrillated cellulose (NFC) powders were prepared by extrusion, followed by injection molding. The chemically modified NFC powders were prepared by carboxymethylation and mechanical disintegration of refined, bleached beech pulp (c-NFC), and subsequent esterification with 1-hexanol (c-NFC-hex). A solvent mix was then prepared by precipitating a suspension of c-NFC-hex and acetone-dissolved PLA in ice-cold isopropanol (c-NFC-hexsm), extruded with PLA into pellets at different polymer/fiber ratios, and finally injection molded. Dynamic mechanical analysis and tensile tests were performed to study the reinforcing potential of dried and chemically modified NFC powders for PLA composite applications. The results showed a faint increase in modulus of elasticity of 10% for composites with a loading of 7.5% w/w of fibrils, irrespective of the type of chemically modified NFC powder. The increase in stiffness was accompanied by a slight decrease in tensile strength for all samples, as compared with neat PLA. The viscoelastic properties of the composites were essentially identical to neat PLA. The absence of a clear reinforcement of the polymer matrix was attributed to poor interactions with PLA and insufficient dispersion of the chemically modified NFC powders in the composite, as observed from scanning electron microscope images. Further explanation was found in the decrease of the thermal stability and crystallinity of the cellulose upon carboxymethylatio

DMA analysis and wood bonding of PVAc latex reinforced with cellulose nanofibrils

Suspensions of commercial refined beech pulp (RBP) were further processed through mechanical disintegration (MD-RBP), chemical modification (CM-RBP) and through chemical modification followed by mechanical disintegration (CM-MD-RBP). Nanocomposites were prepared by compounding a poly(vinyl acetate) (PVAc) latex adhesive with increasing contents of the different types of nanofibrils, and the resulting nanocomposites were analyzed by dynamic mechanical analysis (DMA). Also, the suitability of using the CM-RBP fibrils to formulate PVAc adhesives for wood bonded assemblies with improved heat resistance was studied. The presence of cellulose nanofibrils had a strong influence on the viscoelastic properties of PVAc latex films. For all nanocomposites, increasing amounts of cellulose nanofibrils (treated or untreated) led to increasing reinforcing effects in the glassy state, but especially in the PVAc and PVOH glass transitions. This reinforcement primarily resulted from interactions between the cellulose fibrils network and the hydrophilic PVOH matrix that led to the complete disappearance of the PVOH glass transition (tan δ peak) for some fibril types and contents. At any given concentration in the PVOH transition, the CM-MD-RBP nanofibrils provided the highest reinforcement, followed by the MD-RBP, CM-RBP and the untreated RBP. Finally, the use of the CM-RBP fibrils to prepare PVAc reinforced adhesives for wood bonding was promising since, even though they generally performed worse in dry and wet conditions, the boards showed superior heat resistance (EN 14257) and passed the test for durability class D

Reinforcing effect of carboxymethylated nanofibrillated cellulose powder on hydroxypropyl cellulose

Bionanocomposites of hydroxypropyl cellulose (HPC) and nanofibrillated cellulose (NFC) were prepared by solution casting. The various NFC were in form of powders and were prepared from refined, bleached beech pulp (RBP) by mechanical disintegration, optionally combined with a pre- or post mechanical carboxymethylation. Dynamic mechanical analysis (DMA) and tensile tests were performed to compare the reinforcing effects of the NFC powders to those of their never-dried analogues. For unmodified NFC powders an inferior reinforcing potential in HPC was observed that was ascribed to severe hornification and reagglomeration of NFC. In contrast, the composites with carboxymethylated NFC showed similar behaviors, regardless of the NFC suspensions being dried or not prior to composite preparation. SEM characterization confirmed a homogeneous dispersion of dried, carboxymethylated NFC within the HPC matrix. These results clearly demonstrate that drying of carboxymethylated NFC to a powder does not decrease its reinforcing potential in (bio)nanocomposite

Preparation and characterization of water-redispersible nanofibrillated cellulose in powder form

Water-redispersible, nanofibrillated cellulose (NFC) in powder form was prepared from refined, bleached beech pulp (RBP) by carboxymethylation (c) and mechanical disintegration (m). Two routes were examined by altering the sequence of the chemical and mechanical treatment, leading to four different products: RBP-m and RBP-mc (route 1), and RBP-c and RBP-cm (route 2). The occurrence of the carboxymethylation reaction was confirmed by FT-IR spectrometry and 13C solid state NMR (13C CP-MAS) spectroscopy with the appearance of characteristic signals for the carboxylate group at 1,595cm−1 and 180ppm, respectively. The chemical modification reduced the crystallinity of the products, especially for those of route 2, as shown by XRD experiments. Also, TGA showed a decrease in the thermal stability of the carboxymethylated products. However, sedimentation tests revealed that carboxymethylation was critical to obtain water-redispersible powders: the products of route 2 were easier to redisperse in water and their aqueous suspensions were more stable and transparent than those from route 1. SEM images of freeze-dried suspensions from redispersed RBP powders confirmed that carboxymethylation prevented irreversible agglomeration of cellulose fibrils during drying. These results suggest that carboxymethylated and mechanically disintegrated RBP in dry form is a very attractive alternative to conventional NFC aqueous suspensions as starting material for derivatization and compounding with (bio)polymer

Heterogeneity within AML with CEBPA mutations; only CEBPA double mutations, but not single CEBPA mutations are associated with favourable prognosis

CCAAT/enhancer binding protein alpha (CEBPA) mutations in AML are associated with favourable prognosis and are divided into N- and C-terminal mutations. The majority of AML patients have both types of mutations. We assessed the prognostic significance of single (n=7) and double (n=12) CEBPA mutations among 224 AML patients. Double CEBPA mutations conferred a decisively favourable overall (P=0.006) and disease-free survival (P=0.013). However, clinical outcome of patients with single CEBPA mutations was not different from CEBPA wild-type patients. In a multivariable analysis, only double – but not single – CEBPA mutations were identified as independent prognostic factors. These findings indicate heterogeneity within AML patients with CEBPA mutations

Surface hydrophobization of bacterial and vegetable cellulose fibers using ionic liquids as solvent media and catalysts

The surface hydrophobization through heterogeneous chemical modification of bacterial (and vegetable) cellulose fibers with several anhydrides (acetic, butyric, hexanoic and alkenyl succinic anhydrides) and hexanoyl chloride suspended in an ionic liquid, tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl) imide, [TDTHP][NTf(2)], was studied. Furthermore, in the reaction with hexanoyl chloride, another ionic liquid, N-hexyl-4-(dimethylamino)pyridinium bis(trifluoromethylsulfonyl) imide, [C(6)N(CH(3))(2)py][NTf(2)], was used instead of common organic bases as catalyst and to trap the released HCl. The analysis of the ensuing modified fibers by FTIR, XRD and SEM clearly showed that the esterification reactions occurred essentially at the fibers' outmost layers, not affecting their ultrastructure. The degree of substitution (DS) of the ensuing esterified fibers ranged from less than 0.002 to 0.41; and in all instances, the fibers' surface acquired a high hydrophobicity. This novel approach constitutes an important strategy in the preparation of modified fibers under greener conditions relaying in the use of non-volatile solvents.FCT - SFRH/BD/72830/2010SFRH/BPD/41781/2007PTDC/QUI/68472/2006PTDC/QUI/72903/200