Cross Direction Research Articles

Customization strategies for the solution of linear programming problems arising from large scale model predictive control of a paper machine

Abstract This paper presents an application of a customized linear programming (LP) based model predictive control strategy to the paper machine cross direction (CD) control problem. The objective of CD control is to maintain flat profiles of variables of interest by minimizing worst case deviations from setpoints (defects). These control problems can have as many as 200 actuators (inputs) and 400 sensor measurements (outputs). This large size coupled with the stringent real-time requirement of computing a control move in a few seconds poses a very challenging control problem. Computational results that demonstrate the effectiveness of this strategy will be presented. For typical disturbances this algorithm can compute provably optimal control moves for a 400 input ×400 output control problem in approximately 5 s versus approximately 90 s for a generic LP algorithm on a HP 9000/770 workstation.

Hybrid necrosis as a barrier to gene transfer in hexaploid winter wheat × triticale crosses

An interspecific wheat × triticale hybridization program was initiated with the scope of widening and improving the winter wheat gene pool. However, progress was hampered by severe necrosis that caused the death of F1 hybrids from crosses between the most winterhardy wheat and triticale cultivars. This paper describes hybrid necrosis as the main barrier to gene transfer between winter wheat cultivars Borden, Augusta and Ruby, and hexaploid winter triticales OAC Wintri and K9-6. Crosses with tester lines revealed that the three winter wheats were carriers of the necrotic Ne2 allele. High temperature (30 °C) treatment until heading stage permitted to only partially circumvent the problem. A study of cross direction effects at the backcross level showed that the conventional method (F1 × wheat) was more efficient for plant recovery, but plants produced by the alternative backcross system (wheat × F1) were more self-fertile. Within the most winterhardy germplasm, hybrid necrosis is a major problem for transferring genes between winter wheat and triticale. The use of non-necrotic winter wheat lines such as MC11N, a local winter wheat selection, may have a special value as a bridge to circumvent the necrosis problem. Key words: Hybrid necrosis, Ne genes, wheat × triticale hybrids, cross direction

Elastic Bending Analysis for Plate of Single-Wall Corrugated Fiberboard (On Supported Edges and Uniform Load).

An elastic analysis of stress and deformation was attempted for anisotropic rectangular plates of the single-wall corrugated fiberboard (SWCF) supported by four edges under uniform loading. Stresses distirbution for square and rectanglar plates are discussed by this analysis. Results obtained are as follows. The deflection increases monotonically from zero at plate edges to maximum at the center. Support forces of edges increase from zero at those corners to maximum at those centers. The normal stress in the cross direction (CD) on surfaces of the kraftliner (KL) increases monotonically from zero at edges to maximum at the center. The normal stress in the machine direction (MD) on KL surfaces is symmetical at two maximum points along the MD center line of the plate. The shear stress of KL surfaces distributes antisymmetically, and becomes maximum at four coners and becomes zero on center lines of CD and MD.

計装 プロファイル制御におけるニューラルネットワークを用いた自動チューニングツール

We have developed an automatic tuning tool that defines all tuning constants in profile control in paper and coater machines. The tuning tool is installed in Windows PCs and those PCs are connected to our measurement and control computer systems by Ethernet communication. This tool executes step response tests of cross direction actuators automatically by using neural network theory and it defines automatically all tuning constants for performing cross direction control by using wavelet analysis and neural network theory.

Closed-Loop Analysis and Tuning of Cross-Direction (CD) Control for Sheet-Forming Processes

Abstract This paper presents the closed-loop performance analysis of a cross-direction (CD) control system and explores the tuning criterion for CD control applications. The paper extends the closed-loop analysis from a linear time-invariant causal (or temporal) control system to a linear non-causal (or spatial) CD control system. Although the CD controllers are different from the temporal controllers, both controllers exhibit similar closed-loop behavior, particularly, their disturbance rejection responses. The disturbance rejection expressed in the spectral domain is key to the performance analysis of a CD closed-loop control system. The spectral amplitude ratio can be used for establishing a tuning criterion for CD control applications. Combining the spectral response of disturbance rejection and the power specuum of process disturbances, the potential reduction of process variations can be estimated.

LP methods in MPC of large‐scale systems: Application to paper‐machine CD control

AbstractAn application of a linear‐programming based model‐predictive control strategy to the paper‐machine cross‐direction (CD) control problem is presented. The objective of CD control is to maintain flat profiles of variables of interest by minimizing worst‐case deviations from setpoints (defects). These control problems can have as many as 200 actuatiors (inputs) and 400 sensor measurements (outputs). This large size coupled with the stringent real‐time requiremnt of computing a control move in a few seconds poses a very challenging control problem. The LP‐based strategy is particularly well suited for solving such classes of control problems. This strategy has demonstrated its ability to solve large‐scale control problems (over 100 inputs and 100 outputs) in real time and exhibits robustness to model uncertainty.

Adaptation of cross-direction basis-weight control in paper machines using fuzzy decision logic

An important quality characteristic in the production of paper webs is the range of fluctuations in the basis weight. This should be kept as small as possible. The basis-weight profile is a measure of these fluctuations. Deviations in the profile that arise during the papermaking process can be rectified by installing slice screws across the web and by suitable control functions. However, due to web shrinkage and displacement in the cross direction, the location on which a slice screw is acting in the profile is not known. This relationship, or mapping, is an essential precondition for cross-direction control. If it cannot be implemented accurately enough, the profile develops unevenness and, in the worst case, becomes unstable. This paper describes a method that identifies this relationship by means of statistical process and a fuzzy decision logic, and that appropriately adapts cross-direction control.

幅方向塗工量制御導入結果と新技術の紹介

Today many of the paper manufactures producing coated grades are interested in cross direction coat weight control. Recenthy, Measurex has introduced new technologies for this control. An infrared coat weight sensor measures the coat weight directly with a light profile filter. ProCoat is the intelligent coat weight profile control actuator with LAN-based communication. These features provide optimized results of the cross direction coat weight control. In addition, drying rate control calculates the “Gelpoint” and optimizes each drying device output to maintain the coat surface quality with minimum energy consumption. In this paper, we introduce the successful results of the ProCoat actuator and the infrared coat weight sensor.

Identification and Control for Web Forming Processes

The paper concerns web forming processes such as paper making, polymer extrusion and related coating processes. Discrete orthogonal polynomials arc used in the identification and constrained optimal control of the cross direction (CD) profile. The paper shows (i) the use of discrete orthonormal Chebyshey polynomials to parameterise the CD behaviour, (ii) a Chebyshey domain estimator for CD profile response and (iii) the use of an iterative method lor the constrained quadratic optimisation in the Chebyshey domain of the CD profile.

Method and system of measuring ultrasonic signals in the plane of a moving web

An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the machine direction, MD, and a cross direction, CD, generally perpendicular to the direction of the traveling web, therefor, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web.

幅方向塗工量に関する新しい計測制御技術について

Cross direction coat weight control on blade coaters has rapidly developed since tentative beginnings in the early 1990's. Total engineered solutions consisting of new actuator systems, backing bar designs, measurment and control techniques have been developed specifically for this purpose.Recent results of CD coat weight control installations will be reviewed with special attention paid to the techniques used to minimize grade recovery time following blade changes.

塗工量プロファイル制御

We have developed cross direction coat weight control for coater machines and just applied it to an actual process recently. The operation under control started February 1995 and has gained much effect for operation and good customers satisfactions.The control algorithm is based on our basis weight profile control algorithm that uses expert fuzzy logic and has been applied to many paper machines. And we have added some special algorithm developed for coater machines to the algorithm.

Synthesis of aminated PVCs using an aprotic solvent: DMSO

Materials shortages, inflated raw material and production costs have required vinyl processors to optimize their product yield per pound of raw materials without sacrificing product quality. In addition, to stay competitive in today's markets, companies have been forced to improve productivity. This paper describes a measurement and control system for a vinyl calender. This system uses the distributed microcomputer architecture. The principle objectives of this digital computer system are: 1. Control weight per unit area at the windup to fixed or optimal targets. 2. Control the cross direction zones to maintain a desired profile. 3. Provide a simple, easy-to-use operator interface to facilitate code or product setup, to provide process status, and to maximize control utilization by the operator. 4. Provide management information in graphic and alphanumeric form. This paper also describes scanner and sensor used for measuring the weight per unit area, total and three-zone weight control, target adaptive control, preset control, operator interface via an interactive video, and management inormation. It also presents actual plant results obtained under manual and computer control.

The HLE hybrid dysgenesis syndrome in the midgeChironomus thummi: Differences in the dysgenic potential between strains

After crossing experiments between twoChironomus subspecies the HLE hybrid dysgenesis syndrome occurs non-reciprocally in the F1 hybrids if the males of each of the fourCh. th. thummi strains (HL, So, G, Kr) are crossed to females ofCh. th. piger, strain E. In hybrid egg masses, differences in the strength of the abnormal trait ‘reduced egg hatch’ were found between the differentpiger E ♀ ×thummi ♂ interstrain crosses. From the results it is concluded that eachthummi strain has a specific hybrid dysgenesis potential which determines the severity of the HLE syndrome in the hybrids. The HLE syndrome occurs also in the hybrids of crosses of differentCh. th. thummi strains. In these hybrids the syndrome is only obtained if the male parent descends from a strain which has a higher HLE hybrid dysgenesis potential than that strain from which the female parent is derived. These results demonstrate that the HLE syndrome is not restricted to the hybrids of thethummi × piger subspecies cross. In theCh. th. thummi interstrain crosses the hybrids of that cross direction are normal, which is reciprocal to the cross direction affected by the HLE syndrome. This is in contrast to thethummi × piger subspecies crosses, where the hybrids of one cross direction always show the HLE syndrome and the hybrids of the reciprocal cross direction the Rud syndrome. Thus, the present study also demonstrates that the HLE and Rud hybrid dysgenesis syndrome inChironomus are independent from one another.

Crystal orientation and twinning in cold‐rolled ultrahigh molecular weight polypropylene

AbstractThe mechanisms of plastic deformation in cold‐rolled ultrahigh molecular weight polypropylene (UHMWPP) have been explored by means of wide angle X‐ray (WAXD) pole figures. The melt crystallized UHMWPP slabs were rolled unidirectionally in a two‐roll mill at 408 K as well as in the cross (transverse) direction. In the unidirectional rolling, all reciprocal lattice vectors of (110), (040), and (130) were found to orient preferentially in the film normal (thickness) direction. The cross‐rolling of UHMWPP shows the preferential orientation of the above plane normals in the film thickness direction, but the distribution of poles broadens toward the transverse direction. Such orientation behavior is very different from that of conventional cold‐rolled polypropylene. Various orientation mechanisms involving the orientation of lamellae in the film plane, twinning of the (110) plane and slippage mechanisms have been taken into consideration to account for the observed pole figures. A theoretical simulation has been carried out based on an orientation distribution function approach by introducing a slippage angle along the maximum shear stress in conjunction with intralamellar slip around the transverse direction. This model simulation conforms closely with the experimental WAXD pole figures of the (110), (040), and (130) planes.

A Hybrid Incompatibility Factor in Tribolium castaneum

Hybrid incompatibility and infertility were observed between strains of Tribollum castaneum from India (T-1) and Canada (C). The severity of the syndrome depended on cross direction and temperature. When reared at 32°C, adult hybrids with T-1 fathers produced a high frequency of somatic abnormalities, reduced fertility, and shortened life span. Hybrids with T-1 mothers were normal. At 25°C, abnormalities were more severe and occurred in both reciprocal crosses: hybrids with T-1 fathers died as larvae or pupae, whereas hybrids with T-1 mothers showed a syndrome similar to that produced by T-1 fathers at 32°C. Among a set of strains representing diverse, world-wide geographic origins, eight produced inviable hybrids and nine produced normal hybrids when females were crossed to T-1 males. One of the latter also produced normal hybrids when males were crossed to C females. The syndrome was associated with a dominant factor, H (Hybrid incompatibility factor), which mapped to the ninth linkage group.

Investigation of processing‐structure‐properties relationships in polyethylene blown films

AbstractMolecular orientation imparted during film fabrication is known to have a major effect on mechanical and thermal properties of both glassy and semicrystalline polymers. A three‐variable Box‐Behnken designed experiment was used to study the effects of die gap, die land length, and blowup ratio (BUR) on key linear low density polyethylene (LLDPE) blown film properties at constant final film thickness. In addition, differences in molecular orientation in the films were studied using optical birefringence and shrinkage methods. Measured key film properties were correlated to processing conditions and to measured molecular orientation. Die land length had no significant effect on film structure and properties. All LLDPE films exhibited about 70 to 80% shrinkage in the machine direction (MD) but expanded in the cross direction (CD). Most films exhibited negative in‐plane birefringence. MD Elmendorf tear was found to be inversely related to drawdown ratio and MD shrinkage, suggesting that MD tear is dependent primarily on amorphous chain extension and hence, amorphous segments orientation for LLDPE blown films. Dart impact strength of the films was shown to be related to MD shrinkage and to the induced surface roughness due to varying die gap. In a separate study, blown films of three high pressure LDPEs were fabricated under nearly identical conditions. No correlation was found between birefringence and shrinkage data on the LDPE blown films.

QUANTITATIVE GENETICS OF SEQUENTIAL LIFE‐HISTORY AND JUVENILE TRAITS IN THE PARTIALLY SELFING PERENNIAL, AQUILEGIA CAERULEA

We determined the genetic basis of several traits related to overall fitness of Aquilegia caerulea, a perennial herb of the Rocky Mountains in western North America. To obtain measures of heritability relevant to the evolutionary potential of wild populations, we performed full and partial diallel crosses and studied progeny performance in the field. Based on a joint analysis of two designs with a total of 18 parents and 102 crosses, we detected significant maternal variance for seed mass and emergence time, but this component was negligible for later-expressed traits. Low heritability and evidence that maternal effects on seed mass are largely environmental suggest that in this population there is little evolutionary potential for change in seed mass under conditions experienced during the study. Seed mass varied depending on particular combinations of parents and cross direction. Such an interaction can have several different biological interpretations, including that particular maternal parents selectively provision embryos sired by particular pollen genotypes. Width of the first true leaf after 4 wk of growth and leaf size of juvenile plants at years one and two were significantly heritable and positively genetically correlated. Juvenile survival exhibited significant dominance variance, as expected from evidence of inbreeding depression in this trait. In contrast, for other traits that exhibit inbreeding depression in this population (seed mass and third-year leaf size), dominance variance was negligible.

Structure and Thermo-Elastic Properties of SMC

A calculation process was developed to determine the whole set (in-plane as well as in the cross direction) of thermo-elastic properties of SMC materials on the basis of known properties of components. A typical feature of SMC structure (that the ma jority of reinforcing fibres remain collected in bundles acting as a sieve during the wetting process) is discussed. SMC-composite is held for a transverse isotropic material and is modeled by a symmetric three-layer composite with the centre layer consisting of plane isotropically reinforced fibre composite and the border layers represented by the isotropic particulate composite. The classical laminate theory is used to find the effective deforma tion characteristics of SMC. The properties of the centre layer are expressed in terms of a UD composite. The Kerner-Hashin theory has been proven satisfactory for prediction of particle composite properties in the case when the particle form doesn't differ too much from the spherical one (e.g., the case of a CaCO3 filler). The application of the Lewis-Nielsen theory allows a good agreement between theoretical and experimental values when platelet particle form must be considered (the case of a kaolin filler). An application of a low-profile additive reduces the stiffness of the resin and enhances its thermal expansion. This effect was found especially significant at higher temperatures and could not be described by means of a mechanical model only.

Application of natural geotextiles and related products

This paper presents a review of the development of natural geotextiles and related materials such as wood and bamboo for a wide range of applications. The first category of application consists of structures for water conservation, recharge and storage. The geotextile is used in conjunction with reinforced soil constructions, where small-dimensioned timber and bamboo are used as reinforcement in the form of cribs. Design methods have been developed for earth retaining crib walls and check dams. The second category of application of natural nonwoven geotextiles is for the bases of roads. The geotextile is used in conjunction with bamboo strip reinforcement. Alternatively, the reinforcement system for the road bases consists of bamboo strips used with synthetic or natural ropes in the cross direction to form a grid. The third category of application includes linings for ponds and channels, underdrainage for seepage control and drains for soil consolidation. In the fourth category of application, cement coated natural nonwoven geotextile is used to create a protective layer for the faces of reinforced walls, membranes laid on slopes of storage ponds/reservoirs. This paper briefly mentions some of these applications, which are essentially an extension of the conventional practices replacing synthetic geotextiles with natural geotextiles. Finally, the paper describes the manufacturing developments of natural geotextiles in India.