Effects of hemicellulose extraction on the kraft pulp mill operation and energy use: Review and case study with lignin removal

The implementation of wood extraction prior to pulping (pre-hydrolysis), with subsequent recovery of hemicellulose, is expected to affect the operation of a conventional kraft pulp mill. The magnitude of impacts will depend especially on the extraction conditions. In this specific work, the consequences of integrating the auto-hydrolysis process are studied using a detailed mill balance. A softwood pulp mill in Finland was used as a reference. With 14.1% of wood extracted, the wood demand increased by 15.5% and the steam generation in the recovery boiler by 13.5%. The removal of approximately 17% of lignin from black liquor would put the flue gas side of the boiler back to the original required capacity. In turn, this would enable the simultaneous recovery of lignin and hemicellulose. To make this process economically feasible, the extra revenue from the sales of lignin and hemicellulose products would need to compensate for the additional operating costs in the pulp mill.     

Functional fluid jetting performance optimization

The manufacturing method utilizing digital printing technology offers alternatives to create electronic structures to be used even in microelectronic applications. Material deposition based on digital inkjet technology offers advantages over both traditional mask-etch technologies and other printing methods. Inkjet technology works in an additive manner, reducing material consumption and the amount of created waste. Additionally, the digital nature of the process allows flexible production, e.g., rapid design changes, quick prototyping, and small, customized series. This research paper introduces ink jetting performance optimization utilized in a concept where discrete components and bare silicon chips were integrated in a single module with ink jetted interconnections. Jetting optimization of fluids enhances the droplet placement and volume accuracy that is a critical issue when forming interconnections for dense IC circuits. The overall drop placement error in jet printing is a combination of several error sources such as mechanical, dynamical and material related issues. However, the largest error portion is induced by a single printhead. The printhead related errors can be detected by observing the flight behavior after firing from the printhead nozzle. This paper focuses on optimizing the performance of ejected droplets during flight, i.e., drop formation sequence and minimum flight time variance. The average drop velocities of drops fired from separate printhead nozzles can be used to evaluate the difference in placement on substrate, which in worse case may lead to electrical wiring failures. The performance optimization was done by analyzing the initial state, modeling the drop velocity during flight, optimizing the process parameters to satisfy the model, and accepting the model after verification. Two inks, conductive and dielectric, were evaluated and improvement in placement accuracy was achieved through enhanced uniformity in drop average velocities, a dimensionless number, coefficient of variation was enhanced from 0.051 to 0.040,with conductive ink and from 0.111 to 0.049 with dielectric ink, thus decreasing the velocity related drop placement error.     

Compact UWB PCML bandpass filter with L- and C-shaped resonator

A novel ultra-wideband (UWB) bandpass filter with four resonant modes is proposed based on a parallel coupled microstrip line (PCML) with L- and C-shaped resonators. The coupling factor of the PCML structure depends on the impedance of the feeding network. The PCML coupling factor can be enhanced by using a feeding network with smaller characteristic impedance. With an L-shaped feeding network and C-shaped middle microstrip line a non-uniform resonator is constructed with the first two resonant modes falling within the UWB. The other two resonant modes within the UWB can be obtained by adjusting the width of both the L- and C-shaped resonators. Overall the designed filter exhibits good UWB passband behaviour with insertion loss < -0.2 dB and group delay < 0.15 ns.     

Pathways of hydrogen photoproduction by immobilized Chlamydomonas reinhardtii cells deprived of sulfur

The green algae Сhlamydomonas reinhardtii entrapped in a thin alginate film have been shown to sustain elevated rates of hydrogen photoproduction under anaerobic incubation in sulfur/phosphorus depleted tris-acetate medium. In the present work we studied mechanisms, underlying hydrogen photoproduction by the immobilized culture, particularly, the roles of PSII and starch accumulation/breakdown. DCMU, a specific inhibitor of electron transport in PSII, is known to suppress hydrogen evolution by circa 80% in suspension cultures of S-deprived C. reinhardtii. In immobilized cells DCMU caused successive stimulatory and inhibitory effects on hydrogen photoproduction, both depending on the deprivation status of the algal cell. The inhibitory effect of DCMU was 25% at 70 h of S deficiency when maximal rates of hydrogen photoproduction were observed. Measurements of the light-induced prompt and delayed chlorophyll fluorescence transients and reflectance at 820 nm (P₇₀₀ redox transitions) revealed very rapid decline of PSII activity in the entrapped S-deprived cells as compared with the suspension culture, whereas PSI suffered less. The immobilized culture showed a high capacity to accumulate starch during early stages of S deprivation and relatively high rates of anaerobic starch degradation during the following hydrogen evolution period. DCMU partly inhibited starch breakdown. Results of the present work brought us to the conclusion that PSII-independent pathway of hydrogen evolution is elevated in the immobilized S-deprived cells rather due to the rapid inactivation of PSII, efficient starch catabolism and non-photochemical PQ reduction.     

LTE/Wi-Fi Coexistence in 5 GHz ISM Spectrum: Issues,Solutions and Perspectives

Wireless Personal Communications - The introduction of a high number of small cells in cellular networks and the complementary adoption of WLAN technologies in unlicensed spectrum are interesting...     

Histopathological examination of transurethral electrovaporization of the prostate

Transurethral electrovaporization of the prostate (TVP) has been devised to eliminate prostatic tissue by electric vaporization and to create a dry coagulation layer beneath to minimize bleeding from the site of TVP. However, vaporization induces degeneration due to thermal coagulation deep in the tissue beneath the vaporized layer, and local tissue damage is thus greater than that caused by the standard transurethral resection of prostate (TURP) loop. Since this results in difficulty with histopathological examination, the percentages of tissue-diagnosable area were determined in sections resected using various vaporization electrodes (Roller Loop, Band & Wedge Loop). The percentage of tissue-diagnosable area was 92.0 +/- 3.3% with the standard TUR loop, 2.4 +/- 0.9% with the Roller Loop, 42.7 +/- 21.1% with the Band Loop, and 39.7 +/- 24.4% with the Wedge Loop. Concerning speed of resection, the best vaporization effect was obtained when the speed of operation was 1/2 or 1/3 that with the standard TUR loop. Since the region in which tissue diagnosis was smaller with the vaporization electrode than with standard TURP, more careful examination was required for diagnosis of incidental cancers. Therefore, postoperative observation by PSA measurement appeared to be important.     

A new convexity measure based on a probabilistic interpretation of images

In this paper, we present a novel convexity measure for object shape analysis. The proposed method is based on the idea of generating pairs of points from a set and measuring the probability that a point dividing the corresponding line segments belongs to the same set. The measure is directly applicable to image functions representing shapes and also to gray-scale images which approximate image binarizations. The approach introduced gives rise to a variety of convexity measures which make it possible to obtain more information about the object shape. The proposed measure turns out to be easy to implement using the fast Fourier transform and we would consider this in detail. Finally, we illustrate the behavior of our measure in different situations and compare it to other similar ones.     

Optimizing modulation transfer spectroscopy signals for frequency locking in the presence of depleted saturating fields

A theoretical model of modulation transfer spectroscopy (MTS) that includes pump beam depletion is presented and experimentally verified with data covering visible iodine transitions at 532, 543, and 612 nm. This model is used to determine the values for pressure, interaction length, and saturation intensity that yield maximum MTS signals for frequency locking to iodine transitions. The approach is demonstrated for iodine transitions at 532, 633, and 778 nm, with the results showing that theoretically the frequency instability scales inversely to the absorption coefficient.     

Asymmetric Heterogeneous Catalysis: Science and Engineering

Asymmetric heterogeneous catalysis is a vivid branch of catalysis, remaining, however, largely a domain of organic chemists. The view towards asymmetric heterogeneous catalysis adopted in this review is mainly from catalytic science and engineering. Not only reaction mechanisms, but also catalytic properties, kinetic regularities, as well as chemical engineering aspects, are covered with the main focus on recent developments.