Optimizing Thermal Process for Canned White Beans in Water Cascading Retorts

Based on thermal degradation kinetics and heat transfer expressed as the Ball formula method, a simplified approach was used to optimize sterilization processes for thermal softening of white beans (Phaseolus vulgaris, subsp. nanus Metz., variety Manteca de Leon) Constant retort profiles in a still and end-over-end rotary water cascading retort (Barriquand Steriflow) were used. Quality attributes of beans processed at the optimum were evaluated by a trained taste panel and by a tenderometer. Both approaches could distinguish (P<0.01) between attributes of products from optimal rotary and still processes. End-over-end rotation resulted in faster heat penetration and better quality retention of beans. Texture of white beans processed at 4° or 8°C from the optimal temperature could be distinguished (P<0.01) by the sensory panel and by the tenderometer.     

Evaluation of Residential PV‐EV System for Supply and Demand Balance of Power System

In recent years, there has been a growing interest in ecofriendly technologies such as residential photovoltaic (PV) systems and electric vehicles (EVs). PV systems and EVs will contribute to reducing CO₂ emissions in the residential sector and the transportation sector, respectively. In spite of that, high penetration of PV systems into the power grid can cause grid voltage and frequency stability problems. Also, the growth of the EV market will create an extra electricity load (for charging the EV fleet), leading to an increase in power utility fuel costs. In this research, we proposed the usage of the PV‐EV system as a method of mitigating the impact the spread of residential PV systems and EV on the power grid. We built an PV‐EV system simulation model and investigated the PV‐EV system contribution to the balance of power supply and demand and to reducing the total cost of the household under different electricity pricing scenarios. We also evaluated the effect of uncertainty in the forecasting of load and PV output on the performance of the PV‐EV system.     

A SEMI-EMPIRICAL APPROACH TO HANDLE BROKEN-LINE HEATING: DETERMINATION OF EMPIRICAL PARAMETERS AND EVALUATION OF PROCESS DEVIATIONS

An existing semi-empirical model for simulating product temperature profiles during thermal processing of conduction or convection heating foods under time varying boundary conditions (variable retort temperatures) was extended for the case of broken-line heating products. The use of the method for determination of the empirical heat penetration parameters for broken-line heating curves as defined by Ball (j_h, f_hl, f_h2, x_bh) was evaluated. Starch solutions, showing broken-line heating behavior, were used as a food simulant.
To investigate the consistency of the determined broken-line heating parameters, and to test the applicability of the method when boundary conditions are time dependent, process deviations consisting of drops on the heating medium temperature during the holding phase of a process were evaluated. The model is a promising approach, if the correct empirical parameters are used.     

Grain Growth of the Lime and Periclase Phases in a Synthetic Doloma

Simultaneous grain growth of the lime (CaO) and periclase (MgO) phases was studied in a synthetic, hydroxide-derived doloma over the temperature range 1400° to 1700°C. The grain growth kinetic exponents were 5 and 6 and the activation energies 333±45 and 437±47 kJ/mol for the CaO and MgO phases, respectively. The large kinetic exponents are attributed to the topological restraints of the two phases on the growth of one another. The parameters suggest that the grain growth of the CaO may be governed by Ca²⁺ diffusion within the CaO phase for it is the continuous phase in the microstructure. In most instances for grain growth of the MgO phase, the Mg²⁺ must diffuse through the lime phase, and this process is believed to be limited by movement of associated defects involving Mg²⁺ within the CaO structure.     

SNePSwD: A newcomer to the SNePS family

Abstract

SNePS 2.1 is a knowledge representation and reasoning system that records the dependencies among propositions that are needed to perform a revision of beliefs when a contradiction is detected. The reasoning of SNePS 2.1 is based on a monotonic logic and the system has no provisos for performing an automatic revision of beliefs. In this paper we present SNePSwD that extends the capabilities of SNePS 2.1 along two dimensions: (1) it is able to represent default rules and to perform default reasoning, i.e. the logic underlying SNePSwD is non-monotonic; (2) it accepts the specification of preferences between hypotheses and uses them to decide which hypotheses to discard to resolve a contradiction. This latter possibility allows a semi-automatic contradiction resolution (in some cases, even completely automatic). We discuss the motivations for the creation of SNePSwD, present the form of default rules it uses, discuss the meaning of each of the three kinds of consequence, and describe how preferences can be specified among propositions and how these preferences are used in the process of belief revision. Finally we present examples that illustrate the aspects discussed in the paper.     

Periodontal research contributions to basic sciences: From cell communication and host-parasite interactions to inflammation and bone biology

The periodontium comprises all structures surrounding the teeth, including gingiva, root cementum, periodontal ligament and alveolar bone. Those tissues aim to protect and support the teeth and are challenged by a residing microbiota that leads to subclinical inflammation even in physiological conditions. Periodontitis, a prevalent multicausal inflammatory and destructive disease, develops as a result from complex host-parasite interactions. This unique physiologic and pathologic scenario enables the development of research methods which allows conclusions beyond the simple understanding of periodontal homeostasis. The aim of this viewpoint was to explore potential contributions of periodontal research to a wide array of basic science specialties, such as cell and molecular biology, microbiology, immunology, endocrinology, rheumatology, among others.     

Inverse Superposition for Calculating Food Product Temperatures during In-container Thermal Processing

A procedure was developed for theoretical calculation of internal product temperatures during in-container sterilization of foods. Experimental product temperatures were determined through traditional heat penetration tests (processing in a retort with come-up time of increasing temperature and holding time at constant temperature). These were used to produce, through a proposed inverse superposition solution, a “standardized,” normalized, dimensionless product temperature curve corresponding to the response of product temperature to a constant retort temperature profile. This “standardized” curve was then used, through Duhamel's superposition theorem, to calculate product temperatures for time-varying retort temperature profiles. Limitations associated with the application of Duhamel's theorem were also transferred to the proposed methodology. Theoretical, for perfect mixing, and experimental, for conduction heating, data were used in example calculations.