Seismic Resistance of Timber Frames with Mud and Stone Infill Walls in a Chinese Traditional Village Dwelling

Traditional Chinese wood residences consist of timber frames with masonry infill walls or other types of infill, representing valuable heritage. A field investigation of traditional village dwellings in northern China consisting of timber frames with mud and stone infill walls was conducted. Their construction characteristics are reported, and static cyclic tests were performed on two full-size wood-stone hybrid walls with different configurations (exterior transverse wall and internal transverse wall) and no openings (doors or windows). Their failure mechanics and seismic capacity, i.e., the strength, stiffness, ductility, and energy dissipation, were investigated. The results are compared with a previous experimental study of two full-size timber frames with the same traditional structure but no infill to determine the effect of the mud and stone infill on the lateral resistance. The experimental results indicate that the stone infill has a critical influence on the lateral performance of traditional village buildings, resulting in a high lateral stiffness, high strength (>20 kN), and a high ductility ratio (>10). An increase in the vertical load leads to an increase in the lateral resistance of the timber frame with infill walls, larger for the internal transverse wall than the external gable wall. The incompatibility of the deformation between the timber frame and stone infill is the main failure reason, resulting in falling stones and collapse with undamaged timber frames. Suggestions are provided for the protection and repair of traditional wood residences in northern China.

Geogrid Reinforced Brick Buildings for Earthquake Disaster Mitigations

In the event of a severe earthquake, the walls of brick buildings experience in-plane shear and out-of-plane bending, leading to diagonal crack and corner failure respectively. In this study, an experimental investigation was carried to observe the above damages on brick masonry buildings reinforced with geogrid embedded in bed joint mortar of the walls. It was observed that the geogrid reinforced brick panels showed better shear strength, lateral strength, ductility, etc. A qualitative comparison was made using a sinusoidal shake table test on a one-fourth single-room building model consisting of two sets of corner walls with and without geogrid reinforcement. It was observed that the corner wall without reinforcement showed crack initiation at 0.45g and complete collapse with over toppling of the transverse wall at 0.90g, while no sign of damages for the corner walls strengthened with geogrid reinforcement for any level of shaking.

Wood micro-morphological characteristics of the Tribe Dalbergieae in Nigeria

The present study examined the wood micro-characters of 18 species of the tribe Dalbergieae across 4 genera in Nigeria, following previously described methods by other authors. The species are distributed across all geo-ecological zones of the country but more abundant in the southern area which is characterized by higher precipitation. Findings clearly showed that members of the tribe Dalbergieae have more generic/tribal characteristics than delimiting characters. The species have certain unifying characters such as diffuse pore porosity, simple perforation plates, oblique to orthogonal vessel transverse wall inclination, prismatic/styloid crystals, and non-septate fibres. Vessels were longest and widest in D. saxatilis, about 197.89x104.23µm. On the contrary, the shortest was observed in D. hostilis - 67.62 µm while the narrowest was in D. oligophylla (28.4 µm). While fibre length was highest in P. mildbraedii (331.22 µm±7.5) and smallest in D. saxatilis (0.69 µm±0.0), the ray cells were longest in D. saxatilis (185µm) and shortest in P. santalinoides (41.82µm) respectively. We confirm here that anatomical studies should not be neglected in plant systematics, even though molecular approaches have been the focus in recent times.

Thermohydrodynamic Performance Evaluation of Recharging, Interrupted and Simple Microchannels: A Comparative Study

In this study, a three-dimensional numerical investigation on the thermohydrodynamic performance of a recently proposed recharging microchannel (RMC) is carried out. In this design, a straight microchannel is split into more than one smaller length channels (having individual inlet and outlet) placed end to end. This design enhances overall heat transfer and maintains temperature uniformity across the substrate length. The comparison of fluid flow and heat transfer performance of RMC, interrupted microchannel (IMC) and straight microchannel (SMC) with the same hydraulic diameter and substrate length are presented to explore the effect of geometrical configuration on heat transfer enhancement. The parametric variations include the number of channels (n), transverse wall length (Ltw), channel aspect ratio (α), and flow Reynolds number. The results reveal that recharging microchannel shows better thermal performance compared to simple and interrupted microchannel with a maximum performance factor of 1.80. The results also indicate that the performance factor of RMC increases with an increase in the number of small channels, transverse wall length, and channel aspect ratio. The outcome of this study indicates the possible use of recharging microchannel heat sinks for high heat flux removal applications such as electronic cooling.

The Investigation of Pipe Ends Formation under Reduction Mill Rolling

The paper presents the results of the experimental study of the longitudinal and transverse wall thickness variation at the ends of a oil-well tubing during reduction procedure. It is established that the greatest "contribution" to wall thickness data spread is made by the pipe facets, which is caused by the influence of the reduction regimes and the rolls calibration due to the metal flow into the tapers of groove. In the course of work, recommendations were also made that, in order to reduce the wall thickness variation of pipes, it is necessary to develop the calibration ensuring the decreasing of the intensity of metal flow into the tapers of groove, as well as decrease the reduction at the mill stands, and increase the coefficient of kinematic tension between the stands of the stretch-reducing mill.

Transient Rotational Flow of Radiative Nanofluids over an Impermeable Riga Plate with Variable Properties

The present investigation imparts an analysis on the effect of time-varying rotation and thermal radiation on diversified nanofluids possessing water as base fluid and Magnetite , Cupper Oxide (CuO), and Titania (TiO) as nanoparticles. Variable fluid properties such as variable viscosity and variable thermal conductivity are taken into consideration. Ensuring implementation, Successive Relaxation method is the instrumental in obtaining the most appropriate numerical solution of the transformed differential equations. One of the marvel outcomes of the current study is that moderate rotation reduces the axial and transverse wall shear stresses and augments the heat transfer rate while higher rotation exhibits the reverse trend for Water-Magnetite, Water-Cupper Oxide, Water-Titania nanofluids.

Pinning Effect on Current-Induced Domain Wall Motion in Nanostrip

Pinning effect on current-induced magnetic transverse domain wall dynamics in nanostrip is studied for its potential application to new magnetic memory devices. In this study, we carry out a series of calculations by solving generalized Landau-Lifshitz equation involving a current spin transfer torque in one and two dimensional models. The critical current for the transverse wall depinning in nanostrip depends on the size of artificial rectangular defects on the edges of nanostrip. We show that there is intrinsic pinning potential for a defect such that the transverse wall oscillates damply around the pinning site with an intrinsic frequency if the applied current is below critical value. The amplification of the transverse wall oscillation for both displacement and maximum value of m3 is significant by applying AC current and current pulses with appropriate frequency. We show that for given pinning potential, the oscillation amplitude as a function of the frequency of the AC current behaves like a Gaussian distribution in our numerical study, which is helpful to reduce strength of current to drive the transverse wall motion.