Granular Salt Research Articles

Weak shock compaction on granular salt

This study conducted integrated experiments and computational modeling to investigate the speeds of a developing shock within granular salt and analyzed the effect of various impact velocities up to 245 m/s. Experiments were conducted on table salt utilizing a novel setup with a considerable bore length for the sample, enabling visualization of a moving shock wave. Experimental analysis using particle image velocimetry enabled the characterization of shock velocity and particle velocity histories. Mesoscale simulations further enabled advanced analysis of the shock wave’s substructure. In simulations, the shock front’s precursor was shown to have a heterogeneous nature, which is usually modeled as uniform in continuum analyses. The presence of force chains results in a spread out of the shock precursor over a greater ramp distance. With increasing impact velocity, the shock front thickness reduces, and the precursor of the shock front becomes less heterogeneous. Furthermore, mesoscale modeling suggests the formation of force chains behind the shock front, even under the conditions of weak shock. This study presents novel mesoscale simulation results on salt corroborated with data from experiments, thereby characterizing the compaction front speeds in the weak shock regime.

Augmenting Breast Implant Research: Accessible Methods for Fabricating Miniature Smooth and Textured Breast Implants in a Laboratory Setting.

Because of the association of textured breast implants with breast implant-associated anaplastic large cell lymphoma, anatomically shaped breast implants, which rely on a textured surface to maintain rotational stability, have been recalled from the market. The dearth of anatomically shaped implants on the market reflects a need for novel breast implant technology, which has been traditionally developed by commercial breast implant manufacturers due to the complexities of implant manufacturing. To increase the accessibility of preclinical breast implant research, miniature breast implants made from polydimethylsiloxane were designed and fabricated for high throughput and low-cost prototyping and in vivo testing of both smooth and textured implants in a laboratory setting. Two-piece negative molds measuring 2 × 1 cm were constructed in Fusion360 and 3D printed in Polysmooth filament. Textured molds were painted with a mixture of an epoxy and fine sugar or granular salt to create textured surfaces, while molds for smooth implants were smoothed using ethanol spray. Molds were injected with polydimethylsiloxane and cured for 12 hours at 37°C. The surface topography of laboratory-made implants and commercial textured and smooth implant shells was analyzed using scanning electron microscopy and implants were evaluated in vivo in an immunocompetent rodent model. Implants retained the original dome shape of the 3D-printed molds. Qualitative assessment of scanning electron microscopy images demonstrated similar surface topography between laboratory-made and commercial smooth and textured implants. There was no statistical difference in the diameter or density of the surface indentations of the Allergan's textured implant compared with laboratory-made textured implants (P > 0.05). Finally, the surface topography and thickness of laboratory-made implant capsules were similar to previously published data using industry made miniature silicone devices implanted in rats. This study demonstrates a low-cost, highly customizable approach to fabricate miniature smooth and textured breast implant prototypes for in vivo studies. The accessibility of this implant fabrication strategy allows nonindustry investigators to develop novel implant designs more rapidly for preclinical investigation.

Stability of Iodine in Differently Iodised Salts

Iodine deficiency is a public health problem worldwide. Iodization of salt is a valuable technique to overcome iodine insufficiency. There are, however, problems in uniform iodization of salt. The study was conducted to investigate comparative stability and uniformity of mixing of iodine in iodized salt fortified with aqueous solution of KIO3 (powder grade salt) or the same compound added additionally in dry form (granular grade salt). The research study was conducted in the laboratory of Nutrition, Section of the Food science Division of Nuclear institute for Food and Agriculture (NIFA), Peshawar. Salt samples were prepared in a medium sized salt crushing facility at Lahore. These samples were transported in bulk packing to Nuclear Institute for Food and Agriculture (NIFA), Peshawar. Following 3 types of samples will be prepared; powder grade salt fortified with 50 ppm of iodine as KIO3 solution using drip system, granular grade salt iodized with the same system without additional KIO3 (this grade of iodized salt always lacks complete and homogeneous iodization and needs addition of more iodine to attain the 50 ppm level) and granular grade salt iodized with additional KIO3 to make up the total to 50 ppm. the salt samples were packed in high density polyethylene (HDPE) and low density polyethylene (LDPE) packing separately. Analysis was carried out at the initial stage (0day) and subsequently at monthly interval up to fourth month. By standard iodometric titration all collected salt samples were tested for their iodine levels. Data were statistically analyzed using Statistix version 8.0. ANOVA were worked out by completely randomized design with factorial arrangement. Means were separated using Tucky HSD test. The mean moisture contents of salt packed in LDPE and HDPE varied significantly (P < 0.05), salt packed in LDPE showed higher average moisture contents than the salts packed in HDPE. Effect of iodization type was also significant (P<0.05) on the moisture contents of the salts. Granular salt iodized with drip and additional dry KIO3 had the highest moisture contents followed by granular salt iodized with drip system and the lowest moisture content was exhibited by powdered salt iodized with drip system only. The mean moisture contents of salt during different storage intervals were significantly (P < 0.05) different from each other, except during third and four month, With the salt showing higher average moisture contents during the last month and lowest in the first month. Effect of iodization type was also significant (P<0.05) on the moisture contents of the salt. Granular salt iodized with drip and additional dry KIO3 had the highest moisture contents followed by granular salt iodized with drip system and the lowest moisture content was exhibited by powdered salt iodized with drip system only. The mean moisture contents of salt during different storage periods were significantly (P < 0.05) different from each other, except during third and four month. The salt showed higher average moisture contents during the last month and lowest in the first month. Effect of packing material type was also significant (P<0.05) on the moisture contents of the salt. The mean moisture contents of salt packed in LDPE and HDPE varied significantly (P < 0.05).However, salt packed in LDPE showed higher average moisture contents than that of salts packed in HDPE. The powder salt retained iodine better than the other two salts types used. The iodine retention gradually decreased during storage periods. Among the packaging material used the salt in low density polyethylene showed higher moisture content. During storage intervals the average moisture content increased. The granular salt (grade II) showed maximum moisture content among the three salt types

Analysis of the process of compaction movements of deposits of crushed salt tailings

In the context of chemical industry production, mining waste from saline materials, mostly consisting of granular rock salt, is stored in tailing piles. During this process, several deformational mechanisms are involved. The crushed salt displays a significant visco-plastic response. Several processes such as “dislocation related deformation mechanisms” or “mechanisms related to presence of humidity”, are activated. The granular saline material consolidates and void ratio reduces. Dissolution and recrystallization phenomena is developed because of confining stresses and the presence of water. Consequently, it produces bonding between salt grains increasing the strength of the material and reductions of porosity. This paper describes the compaction process of waste salt materials due to the tailing pile self-weight. Since then, it undergoes a long-term response which may lead to a material with completely different properties.An experimental program was carried out on salt samples obtained from a tailing pile with the aim of studying the mechanical behavior of the material. This experimental research was divided in three stages.First, the geotechnical profile was determined from a comprehensive laboratory characterization. In this research, the behavior of the salt aggregates was studied by means of oedometer compaction creep tests on granular salt samples. The material used was obtained from two different depths. Samples were saturated during two months using a salt solution under isothermal conditions (23 °C). Vertical stresses applied varied from 0.05 to 1.5 MPa. Permeability measurements were obtained from oedometer tests (initial and final measurements). A relationship between permeability and void ratio was established.In a second stage, a constitutive model proposed by Chumbe, 1996 for aggregate saline material has been calibrated by experimental oedometer results. The model predicts strain rate of the salt aggregates subjected to compaction under constant stress, once calibrated. Moreover, the evolution of permeability can also be estimated by the model.Finally, a model, with a relatively simple geometry, is intended to assess porosity reduction in a crushed salt deposit. In this way, the experimental results can benefit of using the viscoelasticity and viscoplasticity constitutive laws for saline materials implemented in CODE_BRIGHT.

Influence of Geological and Environmental Factors on the Reconsolidation Behavior of Fine Granular Salt

Understanding the consolidation behavior of granular salt is of great significance for salt cavern repository design and the corresponding long-term safety assessments. To evaluate the influence of environmental and geological factors on the reconsolidation behavior of fine granular salt, a series of orthogonal array design experiments were performed. The experimental results showed that temperature, compressive stress, moisture content and compression time had significant impacts on the compaction properties of granular salt. The compressive stress exerted the greatest impact on porosity of the granular salt, which decreased the porosity. An increase in moisture content (within 3%) in the granular salt sample substantially reduced the porosity of the sample, whereas this effect was limited when moisture exceeded 3%. In the process of granular salt compaction, all of the deformation mechanisms were temperature dependent. The correlation between porosity and permeability of the dried compacted salt samples was independent of the environmental and geological factors during the compaction of the granular salt. The use of granular salt with a smaller particle size in the compacted salt backfill can improve its sealing performance. In the transient loading stage of granular salt compaction, the porosity decreased rapidly under stress to form a denser layer, which was mainly accomplished by particle rearrangement and cataclastic flow. However, in the constant-load creep stage, the additional porosity reduction was dominated by grain boundary processes and crystal plasticity mechanisms, including dislocation creep, pressure-solution creep and recrystallization.

Foodie traffic fixes

A German gherkin experiment When winter comes, streets crunch underfoot with salt and grit, laid down to lower the freezing point of water. But while most road salt is mined especially for that purpose, the German state of Bavaria has found an unusual source for some of its salt: Gurkenwasser, the brine from pickling gherkins. The Bavarian transport ministry is responsible for treating a total of 23,000 km of autobahns and streets. This creates a bit of a pickle—treating the streets in winter uses a lot of salt, which has both an economic and an environmental cost. Excess salt may run off into groundwater and surface water, so the ministry uses blends of brine and granular salt to reduce waste. At warmer temperatures, wet mixes help the salt stick to where it’s needed. This year, a pilot project will source some of that brine from a local company that makes

Experimental investigation of the influence of pore pressure and porosity on the deformation of granular salt

The influence of pore pressure and porosity on the ductile deformation of granular salt was experimentally investigated under a isostatic compression at elevated temperatures. Confining and pore pressures were independently controlled while granular salt samples exhibited rate-dependent deformation that resulted in large decreases of sample volume and porosity. Over the experimental durations, which ranged from one to seven days, volumetric strain rates generally ranged from 10−2 down to 10−10s−1. The sample deformation rates were observed to correspond with both the sample porosity and the pressure difference between the confining and pore pressures. Experimental results show that the volumetric strain rate decreased when either the sample porosity or the pressure difference were decreased. Post-test observations revealed that the reduced porosity was caused by the solid particles deforming in a ductile manner into the pore volume. Insight into the cause of ductile deformation under isostatic compression was gained by considering the local stress distribution within a sample, which was approximated with the use of a representative volume element. Analysis of the local stress distribution showed how the magnitude of localized shear stress depends on both porosity and the pressure difference, which is consistent with the experimental results.

Investigation on thermal characteristics of novel composite sorbent with carbon coated iron as additive

Carbon coated iron and expanded natural graphite are selected as the additives in developing novel consolidated composite strontium chloride, which is attempted to improve heat and mass transfer performance. Due to anisotropic characteristics, both disk and plate samples are investigated which are parallel and perpendicular to compression direction respectively. It is worth noting that thermal conductivity of composite sorbent increases with the increase of density and the decrease of mass ratio whereas permeability shows a reverse trend. Results demonstrate that the highest thermal conductivity of composite strontium chloride with carbon coated iron could reach 2.95 W m−1 K−1, which is improved by 14 times when compared with granular salt. Permeability of composite sorbent ranges from 1.2 × 10−9 m2 to 4.5 × 10−14 m2 when density is in the range between 400 kg m−3 and 600 kg m−3. Sorption characteristic of composite sorbent with carbon coated iron is also investigated and compared with that not adding carbon coated iron. Under the condition of −10 °C evaporation temperature, sorption reaction rate of composite sorbent with carbon coated iron is better than that without carbon coated iron due to the improved mass transfer performance. Sorption rates of composite sorbents are almost the same when evaporation temperature reaches 10 °C.

Micromechanical processes in consolidated granular salt

Granular salt is likely to be used as backfill material and a seal system component within geologic salt formations serving as a repository for long-term isolation of nuclear waste. Pressure from closure of the surrounding salt formation will promote consolidation of granular salt, eventually resulting in properties comparable to native salt. Understanding dependence of consolidation processes on stress state, moisture availability, temperature, and time is important for demonstrating sealing functions and long-term repository performance. This study characterizes laboratory-consolidated granular salt by means of microstructural observations. Granular salt material from mining operations was obtained from the bedded Salado Formation hosting the Waste Isolation Pilot Plant and the Avery Island salt dome. Laboratory test conditions included hydrostatic consolidation of jacketed granular salt with varying conditions of confining isochoric stress to 38 MPa, temperature to 250 °C, moisture additions of 1% by weight, time duration, and vented and non-vented states. Resultant porosities ranged between 1% and 22%. Optical and scanning electron microscopic techniques were used to ascertain consolidation mechanisms. From these investigations, samples with 1% added moisture or unvented during consolidation, exhibit clear pressure solution processes with tightly cohered grain boundaries and occluded fluid pores. Samples with only natural moisture content consolidated by a combination of brittle, cataclastic, and crystal plastic deformation. Recrystallization at 250 °C irrespective of moisture conditions was also observed. The range and variability of conditions applied in this study, combined with the techniques used to display microstructural features, are unique, and provide insight into an important area of governing deformation mechanism(s) occurring within salt repository applications.

Thermal Properties of Consolidated Granular Salt as a Backfill Material

Granular salt has been proposed as backfill material in drifts and shafts of a nuclear waste disposal facility where it will serve to conduct heat away from the waste to the host rock. Creep closure of excavations in rock salt will consolidate (reduce the porosity of) the granular salt. This study involved measuring the thermal conductivity and specific heat of granular salt as a function of porosity and temperature to aid in understanding how thermal properties will change during granular salt consolidation accomplished at pressures and temperatures consistent with a nuclear waste disposal facility. Thermal properties of samples from laboratory-consolidated granular salt and in situ consolidated granular salt were measured using a transient plane source method at temperatures ranging from 50 to 250 °C. Additional measurements were taken on a single crystal of halite and dilated polycrystalline rock salt. Thermal conductivity of granular salt decreased with increases in temperature and porosity. Specific heat of granular salt at lower temperatures decreased with increasing porosity. At higher temperatures, porosity dependence was not apparent. The thermal conductivity and specific heat data were fit to empirical models and compared with results presented in the literature. At comparable densities, the thermal conductivities of granular salt samples consolidated hydrostatically in this study were greater than those measured previously on samples formed by quasi-static pressing. Petrographic studies of the consolidated salt indicate that the consolidation method influenced the nature of the porosity; these observations are used to explain the variation of measured thermal conductivities between the two consolidation methods. Thermal conductivity of dilated polycrystalline salt was lower than consolidated salt at comparable porosities. The pervasive crack network along grain boundaries in dilated salt impedes heat flow and results in a lower thermal conductivity compared to hydrostatically consolidated salt.

Household and market survey on availability of adequately iodized salt in the Volta region, Ghana

Consumption of adequately iodized salt (AIS) ≥15 ppm is one of the criteria for measuring progress towards universal salt iodization (USI) and sustainable elimination of iodine deficiency disorders. After a series of behavior change interventions aimed at increasing utilization of AIS, this survey was conducted to evaluate extent of achievement of USI. Cross-sectional survey was conducted in 1961 households and 350 markets to estimate the iodine levels of salt consumed or sold. Three degrees of iodization were estimated from fine, coarse and granular texture salt using MBI rapid field test kits. Differences in iodization levels were determined using Bonferroni test in STATA. Determinants for household utilization of AIS were identified using regression analysis and reported as odds ratio (OR). Availability of AIS in households (24.5%) and markets (30.9%) was far below the 90% recommendation. No differences were observed in urban (26.8%) and rural (24.1%) households. Households that used fine-texture salt (OR: 40.13; CI: 30.1–53.4) or stored salt in original packs (OR: 8.02; CI: 6.01–10.70) were more likely to consume AIS. Across districts, highest household availability of AIS was 51.7% while the least was 7.5%. The district with the highest market availability of AIS was 85.7% while the least was 8.3%. Almost 32% of the traders were aware that selling non-iodized salt was unauthorized but out of this, only 12% sold AIS. Health promotion strategies should emphasize appropriate handling and storage of salt throughout the supply chain. To ensure adequate salt fortification with iodine, improved surveillance of factories and mining sites is recommended.

Mechanical Response and Microprocesses of Reconsolidating Crushed Salt at Elevated Temperature

Design, analysis and performance assessment of potential salt repositories for heat-generating nuclear waste require knowledge of thermal, mechanical, and fluid transport properties of reconsolidating granular salt. To inform salt repository evaluations, we have undertaken an experimental program to determine Bulk and Young’s moduli and Poisson’s ratio of reconsolidated granular salt as a function of porosity and temperature and to establish the deformational processes by which the salt reconsolidates. Tests were conducted at 100, 175, and 250 °C. In hydrostatic tests, confining pressure is increased to 20 MPa with periodic unload/reload loops to determine K. Volume strain increases with increasing temperature. In shear tests at 2.5 and 5 MPa confining pressure, after confining pressure is applied, the crushed salt is subjected to a differential stress, with periodic unload/reload loops to determine E and ν. At predetermined differential stress levels the stress is held constant and the salt consolidates. Displacement gages mounted on the samples show little lateral deformation until the samples reach a porosity of ~10 %. Interestingly, vapor is vented only for 250 °C tests and condenses at the vent port. It is hypothesized that the brine originates from fluid inclusions, which were made accessible by heating and intragranular deformational processes including decrepitation. Identification and documentation of consolidation processes are inferred from optical and scanning electron microstructural observations. Densification at low porosity is enhanced by water film on grain boundaries that enables solution-precipitation phenomena.

A Model of Damage and Healing Coupling Halite Thermo-mechanical Behavior to Microstructure Evolution

Creep processes in halite (salt rock) include glide, cross-slip, diffusion and dynamic recrystallization. Diffusive mass transfer (DMT) can result in crack rebonding, and mechanical stiffness recovery. Crack rebonding driven by DMT occurs within a few days at room temperature and low pressure. DMT is enhanced at higher temperatures, which could be beneficial for the sustainabilty of geological storage facilities in salt mines. On the one hand, visco-plastic laws relating creep microscopic processes to microstructure changes are empirical. On the other hand, theoretical models of damage and healing disconnect thermodynamic variables from their physical meaning. The proposed model enriches the framework of continuum damage mechanics with fabric descriptors. In order to infer the form of fabric tensors from microstructure observation, creep tests were carried out on granular salt under constant stress and humidity conditions. The evolution of net damage is governed by a diffusion equation, in which the characteristic time scales with the typical size of halite crystals, and the diffusion coefficient is a function of temperature. A stress path comprising a tensile loading, a compressive unloading, a creep–healing stage and a reloading was simulated. Macroscopic and microscopic model predictions highlight the increased efficiency of healing with time and temperature. The model presented in this paper is expected to improve the fundamental understanding of damage and healing in rocks at both macroscopic and microscopic levels, and the long-term assessment of geological storage facilities.

EFFECTS OF DIFFERENT SALTING PROCESS ON THE STORAGE QUALITY OF MEDITERRANEAN MUSSEL (MYTILUS GALLOPROVINCIALIS L. 1819)

ABSTRACT The effects of brine and dry salting on sensory and quality attributes of mussels stored at 4 ± 1C were investigated in this study. In brine salting method, the mussels were immersed in brine containing 26.4 g NaCl/100 mL water. In the dry salting method, the mussels were salted with a mixture of thin and thick granular salt by using the ratio of mussel to salt as 4:1 by weight. The salted mussels remained in the liquid pickle formed by salt and liquid extracted from the mussels. This solution was not drained during the storage period. Both brine‐salted and dry‐salted mussels were stored at 4 ± 1C. Initial dry matters were 13.94 and 20.75% in raw and boiled mussels, which increased to 32.84 and 39.67%, respectively at the end of the storage time after brine and dry salting. Salt content was 0.87% in raw mussels, and increased to 21.01% in brine‐salted mussels and 25.26% in dry‐salted mussels at the end of the storage period. The total volatile basic nitrogen was 11.83 mg/100 g in raw mussels, which decreased to 2.80 mg/100 g after boiling. The TVB‐N content increased to 7.00 mg/100 g in brine‐salted mussels and 10.50 mg/100 g in dry‐salted mussels at the end of the storage time. Trimethylamine nitrogen values in raw and boiled mussels were 1.13 and 1.01 mg/100 g, respectively, and increased to 3.86 mg/100 g in brine‐salted mussels and 4.10 mg/100 g in dry‐salted mussels at the 120th day of the storage period. The salted mussel was a different taste for consumers. It was concluded that Mediterranean mussels can be consumed for a period of 4 months in refrigerated conditions.PRACTICAL APPLICATIONSSalting is the oldest preservation method for foods. Salting may be dry or wet. The most commonly employed method is a hybrid of the dry and wet methods. The mussels are processed commonly as fried, canned or frozen. This study investigated the suitability of Mediterranean mussels for salting processing. Brine and dry salting processes can be successfully applied to the Mediterranean mussels.

Petrophysical and Capillary Properties of Compacted Salt

This paper reports experimental results that demonstrate petrophysical and capillary characteristics of compacted salt. The measured data include porosity, gas permeability, pore size distribution, specific surface area, and gas-brine breakthrough and capillary pressure. Salt samples employed in the experiments were prepared by compacting sodium chloride granulates at high stresses for several hours. They represent an intermediate consolidation stage of crushed salt under in-situ conditions. The porosity and permeability of compacted salt showed similar trends to those expected in backfilled regions of waste repositories excavated in salt rock. The correlation between the measured porosity and permeability seems to be independent of the compaction parameters for the range examined in this study. The correlation also shows a different behaviour from that of rock salt. The data of all petrophysical properties show that the pore structure of compacted salt can be better characterized by fracture permeability models rather than capillary bundle ones. Simple creep tests, conducted on the fully-brine-saturated compacted salt samples, yielded similar strain rates to those obtained by a steady-state mechanical model developed from the tests on fully brine-saturated granular salt. A modified procedure is proposed for the evaluation of restored-state capillary pressure data influenced by the material creep. The characteristic parameters for the capillary behaviour of compacted salt are determined by matching the Brooks-Corey and van Genuchten models with the measured data. The Leverett functions determined with different methods agree well.

TOXICITY OF SODIUM CHLORIDE TO HOUSE SPARROWS (PASSER DOMESTICUS)

Sodium chloride (NaCl) is widely used as a deicing agent on roadways. There are numerous anecdotal reports of poisoning of passerine birds by road salt in the United States and Canada, but little is known about the toxicity of NaCl to songbirds. The objectives of this study were to determine the lethal dose range for NaCl in a representative passerine species (house sparrow [Passer domesticus]); to determine the clinical, physiologic, and pathologic effects of sublethal and lethal oral NaCl exposure; and to assess the potential for recovery after exposure to granular salt or highly concentrated salt solutions. The up-and-down method was used in a pilot study to estimate the lethal oral dose of granular NaCl in wild caught house sparrows. The toxicity of highly concentrated NaCl solution also was investigated. This was followed by an acute dose response study in which house sparrows were dosed orally with granular NaCl at 0, 500, 1,500, 2,500, or 3,500 mg/kg. Sparrows were deprived of water for 6 hr postexposure (PE) in an attempt to mimic specific winter conditions. Groups of three birds at each dose were euthanized at 1, 3, 6, and 12 hr PE, and samples were collected for histopathology and brain and plasma electrolyte analyses. Results indicated an approximate mean lethal dose (LD50) of 3,000-3,500 mg/kg in water-deprived birds, which is similar to mammalian values. House sparrows dosed with a concentrated solution of NaCl generally died at doses of 8,000 mg/kg. Clinical signs observed at >or=1,500 mg/kg included rapid onset (<30 min) of depression (indicated by reduced activity and reduced response to visual and auditory stimuli), ataxia, inability to fly or perch, and death in as little as 45 min. Birds that survived for 6 hr usually recovered. Plasma Na concentrations >200 mmol/l were consistently associated with clinical signs. Pathologic lesions consisted of edema and distension of the caudoventral thin muscled region of the gizzard and were observed 1 hr PE in most birds dosed with >or=500 mg/kg. Brain Na concentrations in clinically ill sparrows and those that died of NaCl toxicity ranged from 1,297 to 1,615 (mean=1,450; SD=115) ppm wet weight or 5,603 to 6,958 (mean=6,367; SD=454) ppm dry weight, which differed significantly from control birds. No histologic lesions were observed in brain sections of exposed birds, likely reflecting the acute nature of the exposure. However, fluid accumulation beneath the koilin layer of the gizzard was observed in the majority of birds at high dosage levels. These results indicate that passerines ingesting relatively small numbers of road salt granules or small quantities of highly concentrated NaCl solutions are at risk of sodium poisoning.

Review of Food and Medicinal Uses of Capparis L. Subgenus Capparis (Capparidaceae)

Capers of commerce are immature flower buds which have been pickled either in vinegar or preserved in granular salt. Semi-mature fruits and young shoots with small leaves may also be pickled for use as a condiment. The use of capers can be traced to the prehistory. Although Capparis spinosa from the western Mediterranean is the most widely used species, the subgenus comprises 23 species and subspecies occupying large territories from the Atlantic coasts to the Pacific in the Old World. We have recorded medicinal and food uses for 19 species.

Wave‐Based Monitoring Processes in Granular Salt

The goal of this paper is to evaluate the use of electromagnetic and mechanical waves to monitor the evolution of high‐porosity granular salt during constrained loading, thermal changes, and moisture changes. Experimental results show that P and S wave velocities are better correlated with cumulative strain than with stress; the opposite is true for amplitude. This behavior can be explained at the micro‐level using Hertzian and frictional contact laws. The complex dielectric permittivity is primarily sensitive to changes in moisture content; load and compaction‐creep do not alter the prevailing polarization mechanisms. Other observations relate to creep rates, residual effects of temperature cycles and transient changes in wave velocity immediately after flooding. The magnitude of changes in the measured parameters support the monitoring of granular salt backfill with wave‐based techniques.

Ultrasonic wave velocities, gas permeability and porosity in natural and granular rock salt

Gas-permeability and P- and S-wave velocities were measured simultaneously as a function of pressure in core samples of rock salt from the Gorleben borehole Go 1002. In addition, compaction experiments were carried out on granular salt in order to establish velocity-porosity systematics. The initial permeabilities of the Gorleben rock salt vary between 10 −16 and 2∗10 −20 m 2 and are found to be controlled by the grain size of the halite matrix minerals and the amount and distribution of “impurities” (anhydrite, polyhalite) on grain boundaries. Increase of effective pressure to 30 MPa gives rise to a marked decrease of permeability and a significant increase of P- and S-wave velocities due to the closure of grain boundary cracks. Our results are in agreement with literature data reported for in situ permeability and acoustic properties of single crystals, respectively. Compaction of granular rock salt gives rise to a reduction of porosity from about 40% to 2% exhibiting linear relationships between porosity and P- and S-wave velocities for porosities <25%. The combined measurements of gas permeability and ultrasonic wave velocities are found to provide powerful tools for the investigation of dilatancy in rock salt.

The effect of solid lubricants on powder attrition and breakage

Attrition of granular salt (NaCl) in a powder blender has been found to be strongly influenced by varying the air humidity. Systematic studies revealed a significant reduction in attrition, up to an order of magnitude, for the material which was covered with a thin lubricating layer of moisture compared with dry material. Introduction of artificial lubrication by covering the surface of dry particles with a solid lubricant (MoS 2 or talcum powder) confirmed the lubricating effect and its order of magnitude, both in a powder blender and in an annular attrition cell. The effects are quantified in terms of coefficients of the Gwyn formulation of attrition rates. The reduction in attrition attributed to the increased inter-particle lubrication is corroborated by an independent test in which a rod penetrates a bed of particles.