Epitypification of Ceratocystis fimbriata

Ceratocystis accommodates many important pathogens of agricultural crops and woody plants. Ceratocystis fimbriata, the type species of the genus is based on a type that is unsuitable for a precise application and interpretation of the species. This is because no culture or DNA data exist for the type specimen. The aim of this study was to select a reference specimen that can serve to stabilize the name of this important fungus. We selected a strain, CBS 114723, isolated from sweet potato in North Carolina, USA, in 1998 for this purpose. The strain was selected based on the availability of a living culture in a public depository. A draft genome sequence is also available for this strain. Its morphological characteristics were studied and compared with the existing and unsuitable type specimen as well as with the original descriptions of C. fimbriata. The selected strain fits the existing concept of the species fully and we have consequently designated it as an epitype to serve as a reference specimen for C. fimbriata.

Stainless steel imitative crack using X-ray LIGA with suspension electroplating technique

In this research, the Synchrotron X-ray lithography (X-ray LIGA) was implemented to fabricate imitative Stress Corrosion Crack (SCC) for using as a reference specimen of electromagnetic NDT. A pattern of the imitative SCC was created by using X-ray LIGA with controllable shape and size in precise details. The pattern created had a high aspect ratio, which was formed on SU-8 polymer. As a preliminary experiment, the prepared pattern was inserted into a block of pure Nickel formed by an electroplating technique. To develop a reference comparable to stainless steel in terms of electromagnetic response, the technique called “Suspension Electroplating” was implemented to create a block of material from its powder form. A rough magnetic response was then measured by Eddy Current Testing (ECT). The results showed the possibility of creating the desired properties of stainless steel. The SCC pattern will be then inserted to become the reference specimen.

The cyclic response of circular reinforced concrete column to foundation connections strengthened with shape memory alloy bars

This study presents a new method for strengthening the circular reinforced concrete (RC) column to foundation connections with shape memory alloy (SMA) bars and carbon fiber reinforced polymer (CFRP) sheets. In the experimental part of the study, three specimens of RC column-foundation connections were cast and tested. One specimen was used as the reference specimen without strengthening. Two other specimens were strengthened with longitudinal SMA bars and CFRP sheets. These specimens were under a constant axial compressive load and cyclic lateral displacements, simultaneously. Next, initial stiffness, energy dissipation capacity, lateral load capacity, ductility, and residual displacement of the specimens were investigated. Due to the superelastic behavior of SMA bars, the residual displacement of column-foundation connections was considerably less than that of the reference specimen. Compared to the reference specimen, the SMA-strengthened and SMA-CFRP-strengthened connections recovered 71.59% and 76.57% of the residual displacement. Therefore, SMA bars were able to recover residual displacements under cyclic loading. Also, the combination of the SMA bars with CFRP sheet was a promising solution for enhancing the amount of the energy dissipation, lateral load capacity, initial stiffness, and ductility parameters. Compared to the reference specimen, the energy dissipation, lateral load capacity, initial stiffness, and ductility ratio parameters of SMA-CFRP-strengthened connection increased about 43.45%, 76.20%, 81.69%, and 242.45%, respectively. In the numerical part of the study, a subroutine was applied for modeling the SMA materials. For the analysis, this subroutine was linked with ABAQUS software. The numerical results showed a close correlation with the experimental results.

Effect of an acidic environment on a glass fibre reinforced polymer grid

The article deals with the effect of an acidic environment on the mechanical properties of a Glass Fibre Reinforced Polymer (GFRP) grid. GFRP composites are prone to the absorption of surrounding media which are either of a liquid or gaseous state, and this may result in the degradation of their mechanical properties. The effect of an acidic environment is examined on specimens cut from a GFRP grid. The specimens were stored in an acidic bath (pH scale 2 – 2.5) for a period of 0 (reference specimen), 1000, 2000 and 6000 hours. The temperature of the acidic bath was 60°C. The specimens were then tested using three‒point bending and the interlamination shear strength test. During the tests, the load and deformation of the specimens were monitored and flexural strength instead and modulus of elasticity were determined. The characteristics of the specimens exposed to the acidic environment were compared with those of the reference specimen. The experiment demonstrated the effect an acidic environment can have on the properties of GFRP material.

Punching Shear Strength Characteristics of Flat Plate Panels Reinforced with Shearhead Collars: Experimental Investigation

This paper presents an experimental investigation on the punching shear strength of reinforced concrete flat plate slabs with shearhead collars. Eight reinforced concrete slab specimens were casted and tested under static load test, the load was applied at the center of slab by 100x100 mm steel column. The effect of the shapes, diameter and number of stiffeners has been discovered for shearheads through studying its effect on the load-deflection behavior, ultimate capacity, cracking load, failure mode, stiffness, ductility and energy absorption of tested specimens. The experimental results indicates that using square shearhead had achieved a slight increase in punching shear strength about 3% over that circular shearhead using the same surface area. Also, utilize 550 mm shearhead diameter will contribute to increase the punching shear strength about 14.5%. The increase in the number of stiffeners in specimen (CS4) had reduced the ultimate punching shear capacity by 20.3% over reference specimen. The first crack was decreased from 12.5kN to 7.5kN, when increases the number of stiffeners from one to two. The cracking load was increased with the increase of the diameter of circular shearhead from 10kN to 15Kn in specimens of 336mm and 550mm respectively. The specimen with 336mm diameter and 30mm height circular shearhead achieved 427 kN.m energy absorption, it is higher than the energy absorption of reference specimen by 2.6%. Also, using two stiffeners improved the energy absorption by 110.2% higher than the specimen with one stiffener.

Description of Cranial Elements and Ontogenetic Change within Tropidolaemus wagleri (Serpentes: Crotalinae)

Tropidolaemus wagleri is a species of Asian pitviper with a geographic range including Thailand, Vietnam, Malaysia, Singapore, Bruniei, parts of Indonesia, and the Philippines. Tropidolaemus is a member of the Crotalinae subfamily, within Viperidae. The genus Tropidolaemus includes five species, and was once included within the genus Trimeresurus. While some osteologic characteristics have been noted a comprehensive description of cranial elements has not been produced for T. wagleri. An in-depth description of the cranial skeleton of Tropidolaemus wagleri lays the foundation for future projects to compare and contrast other taxa within Crotalinae and Viperidae. The chosen reference specimen was compared to the presumed younger specimens to note any variation in ontogeny. The study here provides a comprehensive description of isolated cranial elements as well as a description of ontogenetic change within the specimens observed. This study contributes to the knowledge of osteological characters in T. wagleri and provides a foundation for a long term project to identify isolated elements in the fossil record.

EFFECTIVENESS OF FRCM SYSTEM IN STRENGTHENING RC BEAMS IN SHEAR USING HYBRID NSE/EB TECHNIQUE

This paper presents an experimental study on the efficacy of a recently introduced hybrid “near surface embedded/ externally bonded” NSE/EB fabric reinforced cementitious matrix (FRCM). Seven medium scale RC beams, deficient in shear, were constructed and tested under three-point loading. Six beams were strengthened using hybrid NSE/EB-FRCM technique and one beam was left un-strengthened as a reference. Two main test variables were considered; viz., strengthening configuration: full versus intermittent strengthening configuration and FRCM type: glass FRCM versus polyparaphenylene benzobisoxazole (PBO). The test results revealed that the hybrid NSE/EB-FRCM strengthening technique is effective in enhancing the shear capacity of the strengthened beams. The strengthened specimens showed an average of 67% higher shear capacity relative to the reference specimen. With regard to the FRCM type, G-FRCM strengthened specimens showed an average of 73% enhancement in the shear capacity, which was 12% higher than the value for PBO-FRCM counterpart. Moreover, the strengthened beams showed higher deflection at the ultimate load than that of the reference specimen. Furthermore, the hybrid NSE/EB-FRCM technique has shown to be a promising alternative to the conventionally used externally bonded FRCM system with the potential to reduce the debonding of FRCM from the concrete substrate.