Series EN Research Articles

Benefits of a Biofilm System and Low Ammonia Levels to Decrees the Early Mortality Syndrome in Shrimp Larvae (Litopenaeus vannamei) Infected with (Vibrio parahaemolyticus)

The world shrimp aquaculture, has faced several problems, causing severe losses in shrimp hatcheries; between the most critical has been diseases such as early mortality syndrome (EMS) caused by (Vibrio parahaemolyticus). The EMS was initially detected in Asian countries; after, it was disseminated to Mexico and other countries. In Mexico, EMS caused severe economic losses during 2013-2016; and it has not yet been eradicated. Various causes for EMS have been reported; none is entirely accurate, but water quality is essential for successful shrimp aquaculture; therefore, the aim this work was evaluate the ammonia concentration effect on susceptibility to (EMS) on post-larvae (PL-15) shrimp (Litopenaeus vannamei) infected with (V. parahaemolyticus), using a biofilm system (water with, microalgae, dinoflagellates, protozoa and other planktonic microorganisms). So series of 5 flasks each one were arranged as following: Series S; 900 ml of filtered seawater (FSW) and 10 PL-15 shrimp per flask. Series SB; 840 ml of FSW, 60 ml of biofilm and 10 PL-15 shrimp. Series E; 900 ml of FSW, infected with 2 ml (V. parahaemolyticus) 106 CFU/ ml and 10 PL-15 shrimp. Series EN; fifteen flasks with 900 ml of FSW, 10 PL-15 shrimp, added with NH4Cl (0.535 mg/ml), to get 0.5, 1.0, 1.5, 2.0 and 2.5 mg/l final ammonia concentration in 5 sub-series of 3 flasks each one. During experiment, ammonia concentration and PL-15 shrimp mortality were evaluated in all flask. Ammonia concentration was higher in series EN than in series E; the same was observed in Series S respect to SB, but at lower values. At end of experiment, mortality in series EN was 90% Vs 60% in E. Similarly, mortality in series S was 10% Vs 0% in SB. This results confirm that the ammonia increases PL shrimp mortality, and biofilm system reduce ammonia and consequently PL-15 shrimp mortality.

Theoretical development of suitable test scenarios for the determination of the bending tensile strength of thin glass with or without influence of edges and their experimental implementation

ABSTRACTThe use of thin glass in the field of electrical engineering for screens of mobile phones or laptops is well known and the necessary material requirements such the scratch resistance has been sufficiently researched. For applications in the building sector, however, the determination of the bending tensile strength of such thin glass necessary for structural design represents a new research topic. The test scenarios described in the standard series EN 1288 relevant for the determination of the bending tensile strength, such as the ring‐on‐ring test or the four‐point‐bending test, are not applicable for glass with a thickness of less than 3 mm. One reason is e.g. the high flexibility of the glass in case of four‐point‐bending tests. As a consequence, these test scenarios have to be adapted or new test scenarios have to be developed. The double‐ring bending tensile test was adapted in that the loading ring, e.g. was replaced by a pressure pad of soft elastomer. Thus, a constant stress distribution in the area under the pressure pad necessary for the determination of the probability of failure could be achieved. The four‐point‐bending test was replaced by test set‐ups in which the force is introduced in‐plane – parallel to the glass surface – as a membrane force in the glass and the glass is thereby deformed or bent until breakage analogous to a stability test. Another variant is bending with a constant bending radius. In this test set‐up, a circular arc is created by precise adjustment of the distance of the supported smaller straight edges and their rotation. Thus, the length of the edge, at which sets a constant bending moment can be increased. These alternative test scenarios were theoretically developed and analysed or partially experimentally investigated by means of test series. These experimental series serve to validate the theoretical development of suitable experimental scenarios and are intended to provide a first approach for a necessary adaptation of EN 1288.

Dynamic modeling approach for determining buildings technical system energy performance

This paper presents new approach for determining buildings technical system energy performance. This new methodology describes a mathematical model for accurately predicting indoor temperature and heat losses of the space heating and domestic hot water system components. The entire model is described by system of ordinary differential equations which can be solved using standard numerical techniques. The innovative aspect of the method is the integral approach in mathematical modeling of buildings energy needs and technical systems heat loss, taking into account heat accumulation in all considered parts (building envelope+technical system). Such approach allows a detailed insight of the system behavior for chosen working conditions. This model can serve for energy performance calculations in a wide variety of buildings types and their technical systems. The calculation example is given for family house, equipped with conventional space heating and domestic hot water heating system, with the time step of 1min and for characteristic day of each month within a year. The results are compared against those obtain from EN ISO 13790 and standard series EN 15316. The comparison shows significant differences in determination of the annual delivered energy to the heating system (33%), as a consequence of difference in estimation of the energy need for heating (15%) and calculation of the technical systems recoverable heat losses utilization factor, which seems to be underestimated. The delivered energy to the space heating and domestic hot water heating system differs 25%, while the energy delivered to the generation system differs 4%.

Quality Assurance in Testing Laboratories

General criteria for the operation of testing laboratories according to standards series EN 45000 and quality assurance under ISO series 9000 are discussed, and other quality management systems too are presented. The important elements of quality assurance as concerns measurements, tests and investigations are pointed out.

Absolute summability of a series associated with a Fourier series

defines the sequence { tn } of (N, Pn) means of jn an. The series En an is said to be summable N, pnl , iff { t I CB V, i.e., En J tn-tnl1 I< K. The (C)-summability of the series n= Ant) has been discussed in detail by Hardy and Littlewood [3], while a necessary and sufficient condition for its convergence is given by Zygmund [7, p. 61]. Concerning the I Cl -summability of the series En?A *(t), Mohanty and Mohapatra [4, Theorem 3] have proved the following.

On the absolute harmonic summability of a series related to a Fourier series

The series Ean is defined to be summable by harmonic means if the sequence { tn } tends to a limit as n-> oo [4 ]. If the series En I tn-tn-1 I is convergent, we say that the series is absolutely harmonic summable. It is known that the method of summability is absolutely regular and implies absolute Cesaro summability of every positive order [2]. 1.2. Let f(t) be a periodic function, with period 2wx, and integrable (L) over (-7r, ir). We assume without any loss of generality that the Fourier series of f(t) is given by

On absolutely convergent Dirichlet series

satisfying 1 b,j < oo, if and only if f(s) is bounded away from zero in the half-plane o?0. This discovery amounts to a determination of the spectrum of the Banach-algebra element associated with f(s), and it thus makes available for the theory of ordinary Dirichlet series the well-known theorem of Gelfand on analytic functions of Banach-algebra elements (see ?24D of [7]) and its generalization, the Silov-Arens-Calderon theorem (Theorem 3.3 of [i]). This paper is intended to show that the theorem of Hewitt and Williamson, together with a similar theorem for general Dirichlet series En=0O a,e-xn8, can be deduced by an elementary argument from a theorem due to Phillips (stated below, in a weakened form, as Theorem 1). The possibility of such an argument arises from the circumstance that the Banach algebra considered by Hewitt and Williamson (and likewise each of the algebras 2{r introduced below) can be enlarged in a certain way without decreasing the spectra of the original elements. No attempt however will be made to examine the maximal ideal spaces of the algebras which occur (the reader who wishes to pursue the subject is referred to the writings [4; 5] of Hewitt and Zuckerman): the object here is to show what can be done without introducing new machinery.

A Tauberian theorem for 𝛼-convergence of Cesàro means

The object of this note is to generalize certain Tauberian results proved by Gehring [3] for summability (C, k; a). The notation is as in [3], with the following additional definitions: If k> -1, then Ak, B' denote the nth Cesaro sums of order k for the series En=oano En=O bn, where bn=nan. An-l' B -' denote an, bn. Summability (C, -1; a) of >an will be taken to mean summability (C, 0; a) of Ea. together with the condition that sequence { nan } be a-convergent to 0. Gehring's Tauberian theorems are:

Asymptotic inverse series

Under sufficiently stringent conditions on the operators Hi this expansion will be valid; in particular, all elements p will be in the domain of all Ai and EitiAi4 will converge to H(t)-10. In more general situations an element 4 may be in the domain of only the first few A j. In this paper we obtain conditions (on Hi and O) for the finite series EN 0 tjAi4 to be a valid asymptotic expansion of H(t)-10; that is, for limt,0 IIt-N {H(t)-14,f -EotiA4o}II to be zero [Theorems 3.1 and 3.2]. Corresponding results are obtained for the inner product (H(t)'lq5, '1) [Theorems 4.1, 4.2, and 4.3]. The results of this study were obtained in the course of the solution of a problem of perturbation theory but they are of wider interest. Their application to perturbation theory will be given in a separate paper. The motivation of some of the hypotheses may be more evident from the point of view of that theory.

A note on the summability of infinite series by sequence to sequence and series to sequence transformations

An infinite series En=, tn with partial sums T. is said to be summed to T by the sequence to sequence transformation A = (aij) in case limi, Z= 1 aijTj= T. It is said to be summed to T by the series to sequence transformation B = (bij) in case limi,. j= b 1j tj = T. A sequence to sequence or series to sequence transformation is regular if it sums every convergent series to its ordinary sum. It is well known that corresponding to every regular sequence to sequence transformation A = (a,j) it is possible to construct a regular series to sequence transformation B = (b^^) by defining bij= En== ain; moreover a series with bounded partial sums is summed by A to T if and only if it is summed by B to T. The requirement that the series have bounded partial sums is essential, as is shown by the following example:

A Non Homogeneous Ergodic Theorem

Such series are of interest for several reasons. (1) In a paper with the same title as that of this one Izumi(2) has explicitly raised the problem of the convergence of (*) and offered a proof that, under certain rather restrictive conditions on f and T, (*) converges almost everywhere. (2) Very elegant necessary and sufficient conditions for the convergence of series similar to (*) are known in the theory of probability(')-an extension of those results would be of significance in the study of asymptotic properties of a more general class of transformations. (3) Since it is an elementary fact(4) that the convergence of the numerical series En=(1 /n)xn implies that limn_ (1 /n) {=1 Xi = 0, the almost everywhere convergence of (*) would be an analytic strengthening of Birkhoff's ergodic theorem. The principal result of this paper (stated precisely in ?3) is that in general (*) does not converge in the mean (of order two). 2. Izumi's theorem. Izumi assumes that the transformation T is uniformly mixing in the sense that