Adhesively bonded joints are increasingly being used in joining various structural components. Adequate understanding of the behaviour of adhesively bonded joints is necessary to ensure efficiency, safety and reliability of such joints. While several joint configurations, such as the single- and double-lap joints have received considerable consideration, the single-strap joint configuration has received little attention, partly because earlier studies have shown it to be the least efficient.
One of the objectives of this paper is to demonstrate that strap joints can be as efficient as lap joints, as long as they are properly designed. This will be done through a detailed analytical investigation into influence of the parameters that govern peak stresses in the adhesive. The next objective is to produce simple equations by which the design of strap joint could be facilitated in an effective manner. For this, the developed analytical expressions are simplified and shown to provide accurate results. The derived solutions provide better insight into understanding the parameters that most influence the edge forces. 相似文献
Recently, Jordan has witnessed increased amounts of medical waste generated at different healthcare facilities. This has resulted
in issuance of Medical Waste Regulation that aimed at regulating the management processes of such hazardous waste. To provide
information on medical waste generation rates, composition and statistical characteristics, a comprehensive sampling survey
was initiated after a regulatory definition of the medical waste was established. Hospitals from Public, private and educational
categories were covered by the survey. This paper presents the findings of the survey. The average generation rates ranged
from 0.29 to 1.36 kg/bed/day, while in terms of patient numbers it is from 0.36 to 0.87 kg/patient/day. The total daily amount
of medical waste generated at the Jordanian hospitals was estimated to be 6 tones/day. The daily amounts of medical waste
generated at King Abdullah University Hospital were found to follow a log normal probability distribution. Physical composition
analysis of the medical waste, which conducted based on the categories identified by the Jordanian Regulation, indicated that
the infectious waste category is the highest, followed by sharps category and finally pathological, cytotoxic and pharmaceutical
categories were the lowest. The study concluded that all hospitals covered by the survey are practicing segregation of hazardous
medical waste from general medical waste. However, the segregation process in some hospitals is still inefficient and there
is a potential for improvements toward minimizing the hazardous medical waste generation. 相似文献
Introduction Hyperphosphatemia and cardiovascular mortality are associated particularly with end‐stage renal disease. Available therapeutic strategies (i.e., diet restriction, calcium [or not]‐based phosphate binders, calcimimetics) are associated with extrarenal blood purification. Compartmentalization of phosphate limits its depuration during hemodialysis. Several studies suggest that plasmatic pH is involved in the mobilization of phosphate from intracellular to extracellular compartments. Consequently, the efficiency of modified bicarbonate conductivity to purify blood phosphate was tested. Methods Ten hemodialysis patients with chronic hyperphosphatemia (>2.1 mmol/L) were included in the two three–sessions‐per week periods. Bicarbonate concentration was fixed at 40 mmol/L and 30 mmol/L in the first and second periods, respectively. Phosphate depuration was evaluated by phosphate mobilization clearance (KM). Findings Although bicarbonatemia was lower during the second period (21.0 ± 2.7 vs. 24.4 ± 3.1 mmol/L, P < 0.01), no difference was observed in phosphatemia (2.4 ± 0.5 vs. 2.3 ± 0.4 mmol/L, P = NS). The in‐session variation of phosphate was lower (?1.45 ± 0.42 vs. ?1.58 ± 0.44 mmol/L, P < 0.05) and KM was higher during the second period (82.94 ± 38.00 vs. 69.74 ± 24.48 mL/min, P < 0.05). Discussion The decrease of in‐session phosphate and the increase in KM reflect phosphate refilling during hemodialysis. Thus, modulation of serum bicarbonate may play a role in controlling the phosphate pool. Even though correcting metabolic acidosis during hemodialysis remains important, alkaline excess can impair phosphate mobilization clearance. Clinical trials are needed to test the efficiency and relevance of a strategy where bicarbonatemia is corrected less at the beginning of sessions. 相似文献
A new approach of direct adaptive control of single input single output nonlinear systems in affine form using single-hidden layer neural network (NN) is introduced. In contrast to the algorithms in the literature, the weights adaptation laws are based on the control error and not on the tracking error or its filtered version. Since the control error is being expressed in terms of the NN controller, hence its weights updating laws are obtained via back-propagation concept. A fuzzy inference system (FIS) with heuristically defined rules is introduced to provide an estimate of this error based on the past history of the system behaviour. The stability of the closed loop is studied using Lyapunov theory. A fixed structure is then proposed for the FIS and the design parameters reduce to the parameters of the NN. The method is reproducible and does not require any pre-training of the network weights. 相似文献
In this paper, the equations of motion for a general multi-link inverted pendulum system are derived. Assumptions previously employed to simplify such formulation are removed. The pendulum system is more general and includes nonlinear friction terms to suit various engineering applications. The generalized equations are first developed in the absolute coordinate system using Lagrange's technique, then a simple linear transformation is proposed to obtain the set of nonlinear equations in the DevanitHartenberg coordinate system. The equations of motion for double and triple link inverted pendulum systems are given as examples for such dynamics equations. 相似文献
The corrosion inhibition and adsorption characteristics of three selected imidazole derivatives namely, 2-amino-4,5-imidazoledicarbonitril
(AID), 5-amino-4-imidazolecarboxamide (AIC) and imidazole (IM) on aluminum in 1.0 M HCl was investigated at 25 °C. Measurements
were carried out under various experimental conditions using chemical (weight loss), and electrochemical (Tafel polarization
and impedance) methods. Molecular dynamics (MD) method and density functional theory were also applied here for theoretical
study. Results obtained showed that inhibition efficiency of these compounds increases with increase in their concentrations
due to the formation of a surface film on the aluminum surface. Adsorption energy as well as hydrogen bond length calculations
showed that AID was the best corrosion inhibitor among the tested imidazole derivatives. Polarization measurements reveal
that the selected imidazole derivatives function mainly as cathodic-type inhibitors. Physisorption, followed by chemisorption
was proposed as the mechanism for the inhibition process. Adsorption via H-bond formation was also considered here. Results
obtained from theoretical study were found to confirm experimental findings. 相似文献
The corrosion behaviour of steel at various concentrations of perchloric acid was studied by weight loss method in temperature range from 298 to 323 K. Results obtained show that corrosiveness of acid increases with its concentration and temperature. The logarithm of corrosion rate was plotted against the acid concentration and values of Hammett Ho and Strehlow Ro(H) acidity functions. The activation energies, enthalpies and entropies of the corrosion process of steel were also determined and fitted against Ro(H). 相似文献