Aggregate Characteristics in Coagulation and Flocculation

Physical characteristics of mineral aggregates (such as density, size, shape, structure and strength) formed by either electrolytic coagulation or polymeric flocculation, need to be critically controlled by optimum conditioning in mineral processing. The present paper discusses the various experimental techniques used to determine these properties. In addition, physical and chemical factors that determine the rates of floe growth and which subsequently influence the floe morphology are summarised. This review also elucidates the hydrodynamic aspects of creeping flow and summarises the various settling velocity equations pertaining to the calcuation of floe density.     

THE WORLD BANK AND HOUSING POLICY IN MADRAS

ABSTRACT: This article offers an explanation and evaluation of three linked housing policy themes: (1) the learn-by-doing experience of the World Bank after 1972, with Madras as the testing ground for the Bank's theory of affordability, cost recovery, and replicability; (2) the Bank and Tamil Nadu government's achievement of substantial progress in tipping the balance of housing policy toward low income residents, 1977–1988; and (3) the neoliberalist political economy of the World Bank is assessed in terms of its performance and by comparison with alternatives such as neo-Marxism and modern theories in social criticism.     

CHARACTERIZATION OF THE SWINE SEX ODOR (SSO) COMPONENTS IN BOAR FAT VOLATILES

SUMMARY —Investigations were undertaken to characterize the volatiles collected from heated boar fat, particularly those components responsible for swine sex odor (SSO). Boar fat volatiles were collected by heating (to 150°C) the ground carcass fat in an all glass distillation apparatus with a liquid nitrogen trap attached. The condensed moisture and liquid nitrogen trap contents were combined and continuously extracted for 48 hr with diethyl ether. The ether was evaporated on a steam bath and the residue subjected to olfactory-gas chromatographic analysis by using a heated collection vent and a flame ionization detector. Using this analytical technique, a perspiration-like odor was detected resembling the SSO that normally emanates from heated boar fat. Further analysis using a gas chromatograph-mass spectrometer unit gave a molecular ion of 272 for this peak and major fragmentation ions identical to a 5a-androst-16-en-3-one standard. This standard was obtained by chromic acid oxidation of 3a-hydroxy-5a-androst-16-ene. Other types of odors were also noted in the boar fat volatile mixture, including those resembling perfume, wood, onion, musk and "Ivory" soap. This research demonstrated the presence of a unique smelling steroid accounting for the perspiration-like odor of heated boar fat. Furthermore, it has shown that the SSO component can be isolated directly from boar adipose tissue at normal cooking temperatures and atmospheric pressure.     

MEAT QUALITY ATTRIBUTES OF CHILLED VENISON AND BEEF

ABSTRACT

Meat quality attributes of venison and beef “semimembranosus” muscle stored at ?1.5 C for 4 weeks were compared. Chilled venison had lower L*, a*, b*and chroma compared to beef. Percent expressible water (PEW), shear force and cook loss were lower in venison compared to beef. μ‐Calpain activities at pH 7.4 and 5.5 were higher and the activity of μ + m‐calpain at pH 5.5 (and not at pH 7.4) was lower in venison compared to beef. L*, a*, b*and chroma in meat from both species increased with chilled storage time (P < 0.01); the increase was higher in beef compared to venison. μ‐Calpain activities at pH 7.4 and 5.5 in venison increased in the first week of storage and then declined in the second while it decreased with time in beef at pH 7.4 and followed similar trend as venison at pH 5.5. Activities of μ + m‐calpain at pH 7.4 and 5.5 decreased with chilled storage time in both types of meat. Shear force decreased with storage time, raw meat PEW increased in the first week and cook loss increased for the first 2 weeks of storage and then declined thereafter in both meats. Within the parameters of this study, the table‐eating quality of venison improved and its color deteriorated faster in chilled storage compared to beef implying that the processing inputs required to maximize meat quality of beef may not be suitable for venison and vice versa.

PRACTICAL APPLICATIONS

The following are some of the practical applications of this research: (1) process variables for optimal quality of table beef and venison differ, processors should tailor their process specifically for each specie; (2) venison producers who supply distant markets should consider the rapid rate of tenderization of venison to avoid supplying products with poor texture resulting from over tenderization; (3) the practice of packaging meat under high oxygen environment to enhance color may affect the quality of venison more than other red meats because of the rapid rate of oxidation in venison relative to these meats; (4) the rapid deterioration in the color of venison underscored the need to come up with a way of convincing the consumer to accept the browner color of venison as an inherent characteristic of this meat in order to minimize any bias against the meat because of its color; and (5) the use of fluorogenic substrates for determining calpain activities if further validated in other studies can be used for the online prediction of tenderness early postmortem.

     

A Review of:“Product Design with Plastics: a Practical Manual.” By Joseph B. Dym. (Industrial Press, 1983.) [Pp.297.] £22-50.

Correct formulation of the master production schedule is critically important for the optimization of the management of a production planning and control system. Most of the models described in the literature solve the problem in two separate sequential stages: lot sizing and then sequencing. This often produces an MPS which is not optimized or even not feasible. On the other hand, when the problem is tackled with models based on mixed integer linear programming, then dimensional constraints have to be respected which can limit the field of applications of the model itself.

A complete heuristic algorithm is presented in this paper which solves the problem of lot-sizing and sequencing in a single logic stage, together with the results of an extensive series of tests carried out to compare, in different types of production systems, the performances of the proposed heuristic and those of another algorithm taken from literature. The model concerns a single production line situation with relevant setup problems; on this production line component availability constraints are not considered (the model refers to mono-level bill of material products, but it can be applied also to the most critical level in multi-levels production systems).     

Some local results for linear systems and implications for state variable feedback

A result concerning the invariance of the infinite-zero structure of a general transfer function matrix under state feedback is obtained. The approach indicates the need for a localized theory of linear systems and some basic results in this area are derived. A surprising property of the infinite-pole structure is also revealed.     

Regional classification of New Zealand red wines using inductively-coupled plasma-mass spectrometry (ICP-MS)

Red wines in a dataset of 120 single-region wines could be classified into seven of the major New Zealand winegrowing regions with an overall accuracy of 80.8% using leave-one-out linear discrimination with the elements Sr, Rb, Ni, Co, Pb, Mn, Cd, Ga and Cs. A higher classification accuracy of 94.4% was achieved when regions were combined into North Island, Nelson, and other South Island regions. The rare earth elements did not prove useful for regional classification, both because of their low and variable concentrations and because their concentrations can be increased upon bentonite fining. Wines originating in the Gimblett Gravels Winegrowing District could be discriminated from wines grown in the remainder of the Hawke's Bay region with a high degree of accuracy using Ba, Cs, Rb, and Pb. A small difference in elemental composition between Pinot Noir, Cabernet Sauvignon, and Merlot wines originating from the Hawke's Bay region was observed. However, despite this difference greater classification accuracy was obtained with a database containing all the red wines than a subset containing only Pinot Noir wines.     

DIFFERENTIATION OF BREWERY YEAST STRAINS BY DNA FINGERPRINTING

A reliable and reproducible non-radioactive DNA fingerprinting technique has been used to differentiate between twelve production brewery yeast strains. The method comprises total DNA preparation from the yeast strains, enzymatic digestion of the DNA and analysis of the DNA fragments by “probing” with known DNA labelled with the plant steroid digoxigenin. A range of probes and several enzymes have been investigated. A successful combination is the restriction endonuclease Hind III and a probe derived from Ty1 (a yeast transposable element). The main advantages of this method are its unambiguity, reproducibility and suitability for routine brewery QC use.