Solid-State NMR Spectroscopy:Towards Structural Insights into Starch-Based Materials in the Food Industry

Solid-state NMR is a nondestructive and noninvasive technique used to study the chemical structure and dynamics of starch-based materials and to bridge the gap between structure–function relationships and industrial applications. The study of crystallinity, chemical modification, product blending, molecular packing, amylose–amylopectin ratio, end chain motion, and solvent–matrix interactions is essential for tailoring starch product properties to various applications. This article aims to provide a comprehensive and critical review of research characterizing starch-based materials using solid-state NMR, and to briefly introduce the most advanced and promising NMR strategies and hardware designs used to overcome the sensitivity and resolution issues involved in structure–function relationships

Computations of shallow foundation settlements using a modular algorithm for data settings and profile sublayering

Department of Civil Engineering, King Saud University, Riyadh, Saudi ArabiaThe need to solve increasingly sensitive structures has placed demands on engineering practitioners to use better tools for settlement computations. The use of computers makes it possible to use rigorous methodologies requiring complex algorithms but result in improved accuracy and economy in settlement calculations. Nonetheless, settlement computation programs are neither developed nor extensive as the many general and widely available suites of computer programs that exist for structural engineering analysis and design. Efficiency in the estimation of settlements is necessary to conduct economical parametric studies that provide insight into real structural behavior. Major and costly decisions are frequently taken on the design of the foundations purely on the basis of burdensome computations. This paper presents an algorithm of a general and highly modular microcomputer-based program for the computation of settlements under shallow foundations. The algorithm is self-complete and could also be conveniently coupled with any general two- or three-dimensional structural analysis programs for study of soil-structure problems. The paper primarily introduces three salient features that have been implemented in the developed program concerning; efficient setting of soil and footing data, a more refined handling of interference of footings, and an innovative sublayering scheme for dividing layers in the soil profiles

Predicting Soil-Water Characteristic Curves of Clayey Sand Soils Using Area Computation

The soil-water characteristic curves (SWCCs) for soils are important for geotechnical engineers in the prediction of clay behavior in case of partially saturated conditions. In the wastewater and waste containment industry, variable clay content is considered. It is not practical to run a time-consuming test several times to obtain the soil-water characteristic curves for every proportion. This study is aimed at introducing a practical procedure to predict the response of clay of known mineralogy and geological setting when clay content within a liner is variable. Fitting curves were performed using Fredlund and Xing’s (1994) equations. The general trends were established for selected clay of known high content of smectite minerals. Obtained curves were examined, and areas under the suction curve were integrated from the starting point to the inflection point for clay-sand material with 5%, 10%, 15%, 30%, 60%, and 100% clay content. This area can be used to estimate the profile of the SWCC for higher or lower clay content based on an area factor determined for a specific clay type or clay of known mineralogy. Other clay of similar nature, but not typical mineralogy, were compared in order to observe and validate the use of the area method in predicting the SWCC for similar soils

Effect of Fiber Reinforcement on the Hydraulic Conductivity Behavior of Lime-Treated Expansive Soil—Reliability-Based Optimization Perspective

Expansive soils which create heave and shrinkage related distresses are considered to be extremely problematic globally. When these soils are used alone or in conjunction with fiber-reinforcement as hydraulic barriers in waste containment systems, their prime purpose is to impede flow. Polypropylene fiber materials are durable and sustain improvement in soil properties in the long run. In order to have intact bonding between the randomly mixed fiber and clay, an additive in the form of lime is considered. In this study, the combined effect of lime and randomly oriented polypropylene fiber inclusion on the hydraulic conductivity behavior of an expansive soil is evaluated. The dosage of lime was fixed at 6% resorting to soil–pH response. The effect of fiber type (fibercast and fibermesh), fiber dosage (0.2, 0.4, and 0.6% by weight of soil) and fiber length (6 mm and 12 mm) on the hydraulic conductivity behavior was studied. Statistical analysis was performed to correlate the hydraulic conductivity of treated expansive soil with dosage and length of randomly oriented polypropylene fibers. Two exponential best fit equations are proposed for estimating the hydraulic conductivity of treated expansive soils in terms of dosage and length of two types of polypropylene fibers. Further, reliability analysis was performed to examine the suitability of treated expansive soils for waste containment in municipal solid waste (MSW) landfills