Milkline vacuum stability in milking machine installations

Transient vacuum drops in the milkline during one ordinary milking were recorded as a measure of vacuum stability in milking installations on 184 Norwegian dairy farms in the summer of 1997. An association between the frequency of vacuum drops and technical data including milkline diameter, length and slope, number of milking units and effective reserve was demonstrated. The direct connection between the transient vacuum drop and its cause could be established for most drops during milking observations. A high frequency of transient vacuum drops in the milkline was associated with a high level of mastitis and a high new infection rate as inferred from changes in somatic cell counts for individual cows. The frequency of vacuum drops during one milking is only a rough indication of the long-term vacuum stability in a specific installation, and must be interpreted with care. The dimensions and slope of the milkline and the effective reserve probably give as good information about the installation's ability to maintain a stable vacuum.     

A high-order harmonic polynomial method for solving the Laplace equation with complex boundaries and its application to free-surface flows. Part I: Two-dimensional cases

A high-order harmonic polynomial method (HPM) is developed for solving the Laplace equation with complex boundaries. The “irregular cell” is proposed for the accurate discretization of the Laplace equation, where it is difficult to construct a high-quality stencil. An advanced discretization scheme is also developed for the accurate evaluation of the normal derivative of potential functions on complex boundaries. Thanks to the irregular cell and the discretization scheme for the normal derivative of the potential functions, the present method can avoid the drawback of distorted stencils, that is, the possible numerical inaccuracy/instability. Furthermore, it can involve stationary or moving bodies on the Cartesian grid in an accurate and simple way. With the proper free-surface tracking methods, the HPM has been successfully applied to the accurate and stable modeling of highly nonlinear free-surface potential flows with and without moving bodies, that is, sloshing, water entry, and plunging breaker.     

On the description of ductile fracture in metals by the strain localization theory

Numerical simulations based on the bifurcation and imperfection versions of the strain localization theory are used in this paper to predict the failure loci of metals and applied to an advanced high strength steel subjected to proportional loading paths. The results are evaluated against the 3D unit cell analyses of Dunand and Mohr (J Mech Phys Solids 66(1):133–153, 2014. doi: 10.1016/j.jmps.2014.01.008) available in the literature. The Gurson porous plasticity model (Gurson in J Eng Mater Technol 99(1):2–15, 1977. doi: 10.1115/1.344340) is used to induce strain softening and drive the localization process. The effects of the void growth, void nucleation and void softening in shear are investigated over a large range of stress triaxialities and Lode parameters. A correlation between the imperfection and bifurcation results is established.     

Computation of Random Errors in Digital Terrain Models

Geostatistical methods make it possible to estimate the random errors in digital terrain models (DTMs) from one single set of measurements. After average interpolating trend removal, the error is derived from the variogram of the residual data set. This method is compared with a procedure that uses triangulation and resampling of two overlapping DTMs for extracting the error component. Eighteen small areas measured with a multibeam echo sounder are selected for the comparison. In the experiment the two methods come out with similar values for the random error. A by-product of the experiment is the development of a model for the average noise reduction caused by resampling of triangle models (TINs). The method we apply for the trend computation has time complexity O(n). Since the noise computation only requires the part of the variogram close to the origin, it is possible to formulate the computation of the random error in DTMs in O(n) time.

Control situations in high-speed craft operation

The control situation framework presented by Petersen (Cogn Technol Work 6(4):266–274, 2004) is elaborated upon in the context of military high-speed craft navigation. An observational study was done on a military navigational exercise in Indre Folda, a stretch of particularly demanding confined waters in Norway. The concept of control strategies is presented as a term related to how navigators choose to take out the control possibilities present in the system. Control actions are viewed as actions that fix the control demands and control possibilities over longer time-scales. Control strategies are different from control actions in that they continuously alter the control demands and control possibilities through its execution.     

Factors affecting mouthpiece chamber vacuum in machine milking

The vacuum in the mouthpiece chamber (MPC) was measured in a factorial trial with two liners (DeLaval 964008-01 and DeLaval 999007-03), two pulsator ratios (60 and 70%) and morning and evening milking over eight milkings of ten cows. Teat length and diameter were measured before and after milking, and maximum milk flow rate and depth of penetration of the teat into the teatcup were also recorded. The MPC vacuum at peak flow rate was classified as stable, at various levels, in 79% of the recordings. In the rest of the milkings the vacuum declined gradually, and this decline was associated with gradually deeper penetration of the teat into the teatcup. The DeLaval 964008-01 liner with the narrower bore and larger mouthpiece opening gave lower MPC vacuum at peak flow rate than did the wider bore DeLaval 999007-03 with the smaller mouthpiece opening. Morning milking gave higher MPC vacuum than evening milking. Increased maximum milk flow rate and increased length and diameter of the teat gave decreased MPC vacuum. The teats were longer before milking in the morning than in the evening. However, during peak flow rate, the teats had penetrated deeper into the teatcup in the evening than in the morning. A marked change in MPC vacuum in the transition to the period of flow rate can be used to identify the start of over-milking of an individual teat. A general model explaining the MPC vacuum as the outcome of the balance between air leakage past the mouthpiece lip and the leakage past the teat in the liner barrel is suggested.     

Bartonella henselae infection in immunocompetent patients: cat scratch disease

BACKGROUND: Cat scratch disease, whose etiologic agent is Bartonella henselae, is a benign disease in immunocompetent subjects, characterized by lymphadenopathy of prolonged course and occasional involvement of other organs such as liver, spleen, central nervous system, eye and lung. In immunocompromised patients, the infection is bacteremic and disseminated. AIM: To report Chilean cases of cat scratch disease. PATIENTS AND METHODS: Ten children (seven male, aged between 6 and 13 years old) with histologically or serologically confirmed cat scratch disease are reported. RESULTS: Lymphadenopathy location was pre auricular in four cases, axillary in two, inguinal in two and epitrochlear in two. Three children had fever over 39 degrees C and two had a parinaud syndrome. Nine children had a history of cat scratch and one of a cat byte. Six had an erythrocyte sedimentation rate over 40. Lymph node ultrasound examination was a useful diagnostic tool. Two patients had splenic granulomas. Lymph node biopsies were obtained in four cases, showing a suppurative granulomatous lymphadenitis in all and a positive Warthin-Starry stain in two. Serology, done in patients without histological confirmation was positive with titles ranging from 1:64 to 1:8192. All patients had a satisfactory outcome with regression of lymphadenopathy. CONCLUSIONS: Infections by Bartonella hemselae occur in the Chilean population and must be considered in the differential diagnosis of regional lymph node enlargement.     

APPLICATION OF MIMO ADAPTIVE CONTROL TO A BINARY DISTILLATION PROCESS

An adaptive controller developed from a generalized cost function is studied in this work. Theoretical derivation is considered first. Application of such controller to a multiple-input multiple-output (MIMO) system—a binary distillation column is examined. Practical issues in the implementation of adaptive regulators to control chemical engineering processes are discussed in detail.